Proii Workbook

PRO/II WorkbookGETTING STARTED

PRO/II Getting Started Workbook The software described in this document is furnished under a License agreement and may be used only in accordance with the terms of that agreement. Information in this document is subject to change without notice. SIMSCI-ESSCOR assumes no liability for any damage to any hardware or software component or any loss of data that may occur as a result of the use of the informa-tion contained in this document.

Copyright Notice Copyright © 2004 SIMSCI-ESSCOR All Rights Reserved. No part of this publication may be copied and/or distributed without the express written permission of SIMSCI-ESSCOR, Rancho Parkway South, Lake Forest, CA 92630.

Trademarks PRO/II SIMSCI, and SIMSCI-ESSCOR are registered marks of SIMSCI-ESSCOR.

Windows, Windows 95, Windows NT, Windows 2000, Windowns XP, and MS-DOS are registered marks and/or trademarks of Microsoft Corporation.

All other products are trademarks or registered trademarks of their respective companies.

Printed in the United States of America, April 2004.

Contents

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Launching PRO/II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Exploring the PRO/II Desktop . . . . . . . . . . . . . . . . . . . . . . 7

Simulation Made Easy . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Building the Process Flow Diagram (PFD) . . . . . . . . . . . 16

Setting the Input Units of Measure . . . . . . . . . . . . . . . . . . 18

Defining the Components . . . . . . . . . . . . . . . . . . . . . . . . . 21

Selecting the Thermodynamic Method. . . . . . . . . . . . . . . 34

Supplying Process Stream Data . . . . . . . . . . . . . . . . . . . . 43

Supplying Process Unit Operations Data . . . . . . . . . . . . . 65

Using Specification and Define Features . . . . . . . . . . . . . 77

Distillation Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Setting up a Case Study . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Working with Keyword Input Files. . . . . . . . . . . . . . . . . 102

Running the Simulation . . . . . . . . . . . . . . . . . . . . . . . . . 103

Generating Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Customizing the Flowsheet. . . . . . . . . . . . . . . . . . . . . . . 113

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

Getting Started Workbook i

Introduction

PRO/II® is SIMSCI's steady-state flowsheet simulator, a product of four generations of development. Like its predecessors, PRO/II is a steady-state heat and material balance simulator - only better. PRO/II delivers rigorous and comprehensive engineering power in an intuitive user envi-ronment. The super-responsive graphical user interface gives PRO/II the flexibility of a true Windows™ environment. PRO/II helps you solve the widest range of industry applications with the greatest ease.

History of PRO/II

SIMSCI designed its first flowsheet process simulator, SSI/100, after the distillation program SP05. Marketed in 1974, SSI/100 had break-through capabilities for its time.

A few years later, SIMSCI created the PROCESS simulation program. PROCESS expanded the component and thermodynamic databases. It added more unit operation calculations as well as flowsheet tools, like an optimizer and a calculator, which has in-line FORTRAN capabilities. This program made flowsheet simulators accessible, since it ran on nearly every mainframe and personal computer. Engineer-friendly terms became the standard for keywords and free formatting made data input easier.

Nevertheless, PROCESS eventually bowed to progress. Over time, the program's limitations became clear: it had a rigid architecture; it ran in batch mode; it was not interactive.

PRO/II - The Calculation

Engine

That is when SIMSCI created PRO/II - the calculation engine of the future. It is easy to install on almost any computer. With a flexible archi-tecture, PRO/II will adapt to future needs, since there is no limit to the number of components, streams, units and recycle loops it can handle.

With larger component databanks and enhanced thermodynamic data methods for chemical, refinery and gas processing systems, PRO/II gives you many powerful options for simulating your systems.

PRO/II technology includes:

■ A state-of-the-art chemical distillation algorithm with reactive and electrolyte distillation capabilities

■ Flexible and powerful refinery capabilities, including a flash-zone model, two types of thermosiphon reboilers and multiple assay blending options

Getting Started Workbook 1

■ Regression and data management tools

■ Solids handling

■ Modeling ability for electrolyte-hydrocarbon systems

■ Flexible modeling capabilities for reaction kinetics

■ Advanced flowsheet sequencing capabilities

■ And much more.

PRO/II - The Graphical

User Interface

The graphical user interface opens PRO/II's architecture to a true Win-dows environment. This “PROVISION” interface displays your process flowsheet diagram with unprecedented clarity and flexibility.

PRO/II features include:

■ Short learning curve because of its easy-to-remember color scheme

■ A true 32-bit Windows-based application

■ Multiple view windows on your flowsheet

■ Graphical output: phase envelopes, assay curves, column profiles, etc.

■ Interactive execution

■ On-line help with hypertext jumps into the reference manual

■ Flash hotkey quickly determines feed stream phase compositions

■ Generate graphs, tables, and charts, and export your results to Excel™, AutoCAD™ and the Windows Clipboard

■ Flowsheet printing on multiple pages

■ OLE/DDE Functionality

■ And many more.

This comprehensive range of features enables your company to use one simulator for all phases of business.

2 Introduction

Where to Find Additional Help

Documents User manuals are shipped with your copy of PRO/II. A complete set of documents is provided on the CD in the form of .PDF files that are most conveniently viewed using Adobe Acrobat Reader, supplied on the installation CD. If you required additional manuals, contact your sales representative.

Online Help PRO/II comes with online Help, a comprehensive online reference tool that accesses information quickly. In Help, commands, features, and data fields are explained in easy steps. Answers are available instantly, online, while you work. You can access the electronic contents for Help by selecting Help/Contents from the menu bar. Context-sensitive help is accessed using the <F1> key or the What's This? button by placing the cursor in the area in question.

Technical Support

PRO/II is backed by the full resources of Simulation Sciences Inc. (SIM-SCI), a leader in the process simulation business since 1966. SIMSCI provides the most thorough service capabilities and advanced process modeling technologies available to the process industries. SIMSCI's comprehensive support around the world, allied with its training semi-nars for every user level, is aimed solely at making your use of PRO/II the most efficient and effective that it can be.

SIMSCI offers technical support for PRO/II for all questions sent by fax, E-mail or regular mail. In North America, call our hotline support at 1-800-SIMSCI1. When contacting Technical Support, please include the following in your correspondence:

■ Name and company, phone and fax numbers

■ Product version number

■ Problem description, including any error messages that you received and the steps necessary to duplicate the problem

■ If you are e-mailing your problem, please include an electronic copy of the .INP or .PRZ file.

■ When calling in a request, please have this workbook available and be near your computer to be able to walk through any difficulties.


About This Workbook

This workbook complements SIMSCI's Introduction to PRO/II training course. Since much of the course time is dedicated to hands-on exam-ples, you will not necessarily go through the document page by page. The workbook does, however, follow the course sequence and you may want to jot notes in the margin. We strongly recommend that you read this workbook from cover to cover once and then use it to refresh your memory later on.

Conventions Before you begin this workbook, you should be aware of several conven-tions. These include:

■ Text written in the SMALLCAPS style is used to denote unit operation names. These items appear on the PFD palette. For example, FLASH, OPTIMIZER, COMPRESSOR and STREAM PROPERTY TABLE.

■ Italicized text denotes menu items, dialog box names and fields, and lists. For example, File, Save As..., the Source Data dialog box, and Composition Defined.

■ Buttons within dialog boxes are represented as gray-filled boxes with white overlaid text, such as , , and .

■ Text in < > brackets indicates keyboard strokes.

■ The icon indicates a cautionary note or a useful tip.

SIMSCI has made great efforts to ensure that PRO/II is compliant with Microsoft Windows. As a result, much of what follows will be familiar to experienced Windows users.

■ Click, Highlight or Select: Place the pointer on the item and press the left mouse button.

■ Double-click: Same as click except you press the left mouse button twice with only a very short pause between clicks.

■ Open: To open a dialog box or object, place the pointer on the object and click or double-click the mouse.

■ Drag: Move the mouse while holding the left button down

Specific PRO/II features include:

■ "..." Ellipses indicate items that, when selected, bring up a window or dialog box, for example, and .

OK Status Add ->

Modify... Enter Data...

4 About This Workbook

■ Underlined words that appear within non-Help windows denote "linked text". Clicking on an underlined word will open a new win-dow or dialog box. A good example of linked text appears in the Flash Drum dialog box when you select Product Specification:

Parameter = value within the default tolerance

If you click on the word, value, for example, a dialog box will open that allows you to enter a number.

■ Underlined words that appear in one of PRO/II's Help screens are "jump text". If you click on the underlined text, you will jump to that section of the Help documentation.

■ Dotted, underlined words that appear in PRO/II's Help screens pop-up a short definition window when pressed. They differ from jump text in that they do not change the current Help window, they simply add an additional window to the screen.

Note: Save your work often! PRO/II does have an autosave feature but you should still save regularly to the simulation database.


Launching PRO/II

To initiate a PRO/II session:

➤ Click Start on the taskbar, select Programs and then SIMSCI.

➤ Click on PRO/II.

A Welcome to PROVISION dialog box appears describing how colors indicate data entry status.

Figure 1: Welcome to PROVISION Dialog Box

➤ Click , then choose File from the menu bar.

The File menu is described below.

Table 1: File Menu OptionsOption Function

New Initialize a new simulation

Open Open an existing simulation

Close Close the active simulation

Save/Save As Save the active simulation to a file with the same name, or to a new file

Delete Delete an existing simulation

Copy Create a new simulation as a copy of an existing one

Import Load a keyword input file into PRO/II

Export Export the active simulation to a keyword input file, or the flowsheet drawing to the Clipboard, Autocad DXF, or Postscript file

Run Batch Run an existing keyword input file without loading it into PRO/II

Print/Print Setup Print the flowsheet drawing or output report

Exit Close the active simulation and exit the program

OK

6 Launching PRO/II

Exploring the PRO/II Desktop

The visual engineering of PRO/II makes building a simulation easy. Functional colors, menu-graphics and picture icons guide you every step of the way. On-line references refresh your memory on equations and guidelines. And if you encounter trouble, Help is available when you need it.

Main Window

The PRO/II main window, shown in Figure 2, is your primary work-space. This window forms the interface between you and the PRO/II pro-gram. This is where you will build and run all your simulations, as well as open files, save the current data, or exit the program.

You will use all the familiar Windows features such as multiple views, toolbar buttons, menus, dialog boxes, drop-down lists and hotkeys.

Figure 2: PRO/II Main Window


Menu Bar Directly below the title bar of the main PRO/II window you will find the main menu bar. It gives you easy access to the command menus.

Many of same commands are available through the buttons on the tool-bar.

Table 2: PRO/II Main Window ComponentsComponent Description

Title Bar The window title contains the name of the current simulation and view.

Menu Bar All functionality can be accessed through the menus.

Toolbar Shortcut buttons for many commonly used PRO/II operations are provided. These include data entry window buttons, pan and go-to buttons, run function buttons and PFD tool and drawing buttons.

Primary Workspace This is where you draw your flowsheet. You can have multiple views of the flowsheet open at the same time.

Scroll Bars The vertical and horizontal scroll bars enable you to move vertically and horizontally through a window.

Status Bar The bar at the bottom of the window gives quick help on the highlighted button or window.

PFD Palette Also known as the Unit Operations Palette, you use this to add unit operations and streams to your flowsheet. You can show or hide this palette and change its position on the screen.

Run Palette Use this palette to run your simulation interactively. You can show or hide this palette and change its position on the screen. Usually, the shortcut buttons on the toolbar are used instead.

Control-menu Box The standard Windows control-menu in the top left corner can be used to move, resize or close the application window.

Table 3: PRO/II Menu BarMenu Main Functions

File File operations: open, close save, import, etc.

Edit Manipulate objects on the main window

Input Add input data - all data can be entered from this menu

Output Define, create and view simulation output

Tools Flash streams, binary VLE curves, output to spreadsheet

Draw Add text, lines or objects to the drawing

View Specify what appears on the main window

Options Customize the working environment

Window Create and manage views on the flowsheet diagram

Help Access the on-line help functions

8 Exploring the PRO/II Desktop

Toolbar The toolbar appears just below the menu bar on the main PRO/II win-dow. Using the mouse, you can initiate many actions by clicking the but-tons on the toolbar.

If you have a low resolution screen, such as 640x480 VGA, you can change this standard toolbar to the compact toolbar (which contains fewer buttons) by selecting the Toolbar option on the View menu.

Table 4: PRO/II Toolbar ButtonsButton Description Button Description

Open a new flowsheet view

Search for a unit in the current flowsheet

Hide or display the PFD palette

Search for a stream in the current flowsheet

Provide a description for the simulation

Flash the selected feed stream

Select units of measurement

Create a binary VLE plot

Select components

Run the simulation

Specify component data

Stop the simulation

Select thermodynamic methods

View the results for a selected unit or stream

Specify assay cut point data and characterization methods

Generate an output report

Define reaction data

Delete the currently selected flowsheet object

Enter kinetic reaction procedures

Zoom in or out

Define a case study

Display the entire flowsheet in the main window

Select calculation sequence

Zoom in on a region of the flowsheet

Specify recycle convergence options

Clear extraneous lines and dots from your PFD

Display the pan view window

Display help for the selected object (main window only)


Data Entry Windows

PRO/II provides dialog boxes that allow you to enter data in a logical manner. Throughout this workbook, you will see examples of data entry windows. Within these dialog boxes, there are many different types of data entry devices including check boxes, radio buttons and drop-down lists.

Grayed buttons indicate that the feature is not currently available.

Color Cues PRO/II uses color cues to inform you of the status of your simulation. Colors are used to indicate:

■ Completeness of data supplied for units, streams and overall simula-tion parameters

■ Real-time execution status of each of the unit operations.

The significance of the colors you will encounter while working with PRO/II are summarized below.

Table 5: Data Entry Window ButtonsButton Description

All data are saved and the dialog box is closed.

All data entered or modified are lost when the dialog box closes.

Displays context sensitive help for the active data entry field, or for the dialog box itself (if there is no active field).

Displays the main help dialog box for the data entry window.

Displays the results of the data consistency checks performed for the main dialog box.

Selects a units of measure set for the selected data entry field.

References one stream or unit parameter value to another stream or unit parameter.

Displays the valid range of values for the active data entry field.

OK Cancel Help

Overview Status

UOM Define

Range

Table 6: Color Significance During Data EntryColor Significance

Red Required data

Green Default data

Blue Data you have supplied or modified

Yellow Questionable data: supplied data value is outside the normal range

Gray Data field is not available to you

Black Data entry is optional


Palettes PRO/II provides two palettes: a PFD palette and a Run palette. Both are displayed in Figure 2.

PFD PaletteYou add unit operations and streams to the flowsheet with the icons on the PFD palette. You can show or hide the PFD palette using the PFD Palette button on the standard toolbar.

Run PaletteFor most simulation calculations, the Run and Stop buttons on the tool-bar, which start and stop the calculations, are all you will need. The Run palette allows you to take more control of the calculations by calculating units one at a time or introducing breakpoints.

Viewing the Flowsheet

PRO/II allows you to pan over the flowsheet, search for a specific unit or stream, and view multiple views of the same flowsheet.

PanningYou can pan the contents of the flowsheet using the Pan View window, which is opened by clicking the Pan View button or by selecting View/Pan View from the menu bar. This window gives a panoramic view of the entire flowsheet. A bounding box identifies the area of the flowsheet vis-ible in the active view. You can move the bounding box to view a differ-ent region of the flowsheet, or you can change its size to adjust how much of the flowsheet is visible in the active view.

Table 7: Color Significance During ExecutionColor Significance

Pale Green Unit operation has not been calculate

Green Unit operation is in the process of being calculated

Blue Unit operation has been solved

Red Unit operation has failed to solve

Magenta Unit operation is at a breakpoint

Dark Blue Unit operation was solved in a previous run


Figure 3: PFD with Pan View

Window

Searching for a Unit or StreamPRO/II builds two lists to identify and locate flowsheet units and streams. The Unit List stores unit operation names, while the Stream List stores stream names. To search for a unit or stream, click on the appro-priate Search for button on the toolbar, or select View/Unit List from the menu bar. Highlight the unit or stream of interest. This centers the object in the active view.

Multiple View CapabilitiesIf you have a large flowsheet, you may want to take advantage of PRO/II's multiple view capabilities. With these capabilities, you can view different portions of your flowsheet at the same time. To get an additional view of your flowsheet, click the Multiple Viewport button on the toolbar, or choose Window/New View from the menu bar. You can change the region of the flowsheet, as well as the magnification level without affecting the original flowsheet view.

The Window menu also contains options for cascading and tiling your flowsheet views. Simply choose Cascade, Tile Horizontally, or Tile Ver-tically from the Window menu. To change the active view, click on the title bar of the desired view, or highlight the name of the view from the Window menu.


Editing the Flowsheet

You can use the options on the Edit menu to modify your flowsheet dia-gram. Most of these commands are accessible upon selecting (highlight-ing) one or more appropriate flowsheet objects. Table 8 describes these Edit options in more detail.

Table 8: Edit Menu OptionsOption Function

Undo Allows you to undo or redo the last action, if possible.

Cut Removes a single selected feed stream from the flowsheet. The cut stream and its data are stored in the Clipboard.

Copy Copies selected stream data or stream property table data to the Clipboard.

Paste Pastes feed stream data from the Clipboard into a flowsheet stream.

Paste Special Pastes feed or product stream data into a flowsheet stream.

Select All Selects (highlights) the entire flowsheet.

Select None Deselects all flowsheet objects.

Insert Object Inserts pictures or other objects onto the flowsheet.

Delete Deletes any highlighted object(s).

Rotate Rotates the selected object(s).

Flip Flips the selected object(s) either horizontally or vertically.

Restore Icon Size Restores the size of the selected icon(s) to their default size for the current magnification level.

Align Text Left, right, or center justifies the selected text items.

Display Style Changes the style of a highlighted unit operation icon.

Reroute Redraws an unobstructed path for the selected flowsheet stream(s).

Collapse Collapses the selected units into one unit, as a block diagram (sub-flowsheet).

Expand Expands a block diagram (sub-flowsheet), converting a single unit into its components.

Rename Renames a block diagram (sub-flowsheet).

Move Up With an external feed or product stream selected in a sub-flowsheet, the free end of this stream is moved up to the next flowsheet above the current sub-flowsheet.

Move Down With an external feed into a sub-flowsheet or an external product stream from a sub-flowsheet, the free end of the stream is moved down to the sub-flowsheet. The stream no longer appears on the main flowsheet, only in the sub-flowsheet.


Simulation Made Easy

Now you will learn how to set up simulations, run them, and analyze the results with PRO/II. When setting up a simulation, you can supply data in a number of ways. The color codes in PRO/II alert you when data are required, marking the pathway towards a completed simulation.

A Systematic Approach

Because some options depend on others, you should establish a routine, logical approach for entering the data. For instance, you cannot enter the stream composition or composition-based process specifications before declaring the components in the process. You may want to change the input set of units of measure before entering user-defined components and streams. All calculations hinge on your choice of thermodynamic methods.

When using PRO/II to develop a simulation, we recommend that you follow these steps:

Build the FlowsheetDraw your process flow diagram (PFD) by selecting and positioning the unit operations. Next, draw the feed and product streams for each unit. Often a product stream from one unit is the feed stream to another unit. Entering such streams connects the flowsheet together and establishes the transfer of information within the simulation.

Check the Input Units of Measure Almost every quantity has a unit of measure. Initially the global default for units of measure set is English. You can change this set for this simu-lation only, or change the global default for all simulations. You can also locally override individual dimensional units in data entry windows.

Buildthe PFD

1

Check theUnits ofMeasure

2

Definethe

Components

3

Selectthe

Thermo

4

SupplyStream

Data

5

ProvideProcess

Conditions

6

RunSimulation &View Results

7

1

2

14 Simulation Made Easy

Define the ComponentsYou can directly define your components by typing their library compo-nent names, by selecting from lists of components, or by entering user-defined components, pseudocomponents, solids with associated particle size distributions, and polymer components.

Select the Thermodynamic MethodSelecting the proper thermodynamic methods is a critically important step in the solution of a simulation. For most simulations, a predefined set of thermodynamic methods for calculating K-values, enthalpies, entropies, and densities can be used. PRO/II offers numerous categories of method sets. Normally you will want to use one of the thermodynamic systems in the list of Most Commonly Used methods.

Supply Process Stream DataFor feed streams, you must supply thermal conditions, flowrates, and compositions for all external feed streams to the flowsheet. For assay streams, you must input the thermal conditions, flowrates, distillation curve data and average API or specific gravity. It is usually desirable, although not necessary, to provide estimated data for recycle streams to speed convergence of recycle calculations.

Supply Process Unit DataSupply process data for each unit in your flowsheet. Unit operation iden-tifiers for which data entries are needed are marked with red borders. To enter information for a unit operation, double-click its icon to open the Unit data entry window.

Run the Simulation and View the ResultsBefore you try to execute the simulation, check that there are no red-bor-dered fields or red linked text. If all the borders are blue, green, or black on the toolbar buttons, unit operation labels, and stream labels then you have supplied enough information to run the flowsheet.

Output is written to the output (*.OUT) file. You can view your results in a variety of ways ranging from plots and tables to pop-up windows with values for each stream and unit.

The remaining chapters will explain each of these steps in extensive detail.

3

4

5

6

7


Building the Process Flow Diagram (PFD)

The first step in any simulation, no matter how small or large, is to draw the process flow diagram. While there is a close correspondence between an actual flowsheet and its simulation flowsheet, there are some notable differences. These are:

■ Time dependencies

■ Combined units

Time Dependencies

Because PRO/II is a steady-state simulator, process equipment that con-trol time-dependent phenomena are not directly relevant to your simula-tion. The depressuring unit is the only exception. Omit units such as control valves and instrumentation. However, consider the instrument settings when you are deciding on the specifications to make in your flowsheet.

Thus

simplifies to

All the control valves, pressure and temperature indicators have been eliminated. You can also eliminate utility systems such as cooling water (as here), steam and refrigerants from the simulation if you are only interested in the duties they provide.

TI TIPI PI

LC LC LC

16 Building the Process Flow Diagram (PFD)

Combined Units

Certain unit operations can be combined to simplify your PFD. For instance, the COMPRESSOR unit in PRO/II includes an aftercooler and most unit operations include a downstream separator.

Thus

becomes

The second compressor's aftercooler and separator have been eliminated because they are incorporated in the COMPRESSOR model. The first com-pressor's aftercooler has been eliminated but we cannot eliminate the first separator because of the recycle from the second compressor.

Flowsheet Defaults

Figure 4 shows the default stream designations for the simple heat exchanger, the flash drum, and the column unit in PRO/II.

Figure 4: PRO/II Unit Defaults


Setting the Input Units of Measure

Almost every item of data you will enter in PRO/II will have Units of Measure. For simplicity, units of measure in PRO/II have been arranged into three standard pre-defined sets: English, Metric and SI. You select the set that nearest matches the needs of your simulation and then over-ride the pre-defined units for individual quantities. For example, you can select the Metric Set and override the Celsius temperature unit with Kelvin.

You can set the units of measure on a global, simulation, and/or field level.

Simulation Defaults

The easiest and most efficient way to enter data involves setting the input units of measure for the active single simulation, and then proceed to change the units of measure for a specific field of a unit dialog box, if necessary.

To change the default units of measure set for a simulation, click the Units of Measure button on the toolbar to open the Default Units of Mea-sure dialog box.

Figure 5: Default UOM for

Problem Data Input Dialog Box

➤ To change the default set, click , select a set, and click .

➤ Make any changes to individual units, as desired.

Initialize from UOM Library OK

18 Setting the Input Units of Measure

You can also use this dialog box to override the true vapor pressure tem-perature basis, the Reid vapor pressure calculation method, and standard vapor conditions.

UOM Library You can define and save your own customized sets by selecting Units of Measure Lists from the Options menu.

GlobalDefaults

By default, the standard English set is the global default used to start each simulation. You can change this global default with your own mod-ified set so that every subsequent simulation starts with that set.

➤ Select Simulation Defaults/Units of Measure from the Options menu and select your set from the list.

Figure 6: Default Sets of Units

of Measure

Output Units of Measure

Normally, the output report is in the same units as the input set. How-ever, you can define a different set of units for the output.

➤ Select Simulation Defaults/Units of Measure from the Options menu and select from the lists.

If you do want output in a different set of units it is good practice to get it in the input unit set as well, so that you can check the correctness of your input data.

➤ Select Same as Input for the First Output and your required output set for the Second Output.

Changingthe UOM for

a Single Field

When entering data in a data entry window, you can still enter individual data items in any appropriate unit.

➤ Place the cursor in the field for the item whose units you want to change.

➤ Click at the top of the dialog box to open the Convert Units of Measure dialog box.

UOM


Here you can choose to change the units and retain the value you entered in the field, or to convert the value to the new units.

Figure 7: Convert Units of

Measure Dialog Box

Notice, however, that the next time you open the data entry window the value will have been converted to the defined global unit of measure.

Standard Sets

The units of measure in the standard sets are shown below.

Table 9: Standard Units of MeasureEnglish Metric SI

Temperature °F °C K

Pressure psia kg/cm2 kPa

Weight lb kg kg

Time hr hr hr

Length ft m m

Fine Length in mm mm

Velocity ft/sec m/sec m/sec

Energy Btu kcal kJ

Work hp kW kW

Duty 106 Btu/hr 106 kcal/hr 106 kJ/hr

Heat Transfer Coefficient Btu/hr-ft2-°F kcal/hr-m2-°C kW/m2-K

Thermal Conductivity Btu/hr-ft-°F kcal/hr-m-°C W/m-K

Viscosity cp cp Pa-sec

Kinematic Viscosity centistoke centistoke centistoke

Surface Tension dyne/cm dyne/cm N/m

Liquid Volume ft3 m3 m3

Vapor Volume ft3 m3 m3

Petroleum Density API gravity kg/m3 kg/m3

20 Setting the Input Units of Measure

Defining the Components

Types of Components

In PRO/II, you can enter the chemical species, or components, that exist in the flowsheet in six ways:

■ As library components

■ As petroleum components (or an assay curve)

■ As user-defined components

■ As solid components

■ As polymer components

■ As ionic components

Library Components

The PRO/II component libraries provide easy automatic access to prop-erty data for nearly 2000 pure components. When running a simulation, you can retrieve the thermophysical properties for a library component from the PRO/II database simply by using an access name or alias. Many components have more than one alias. For example, you can retrieve information on methane, using any of the following:

■ C1

■ CH4

■ METH

■ METHANE.

PRO/II contains extensive component databanks as well as comprehen-sive methods for component property prediction. In general when PRO/II retrieves component data from one of its libraries, it also retrieves the necessary component properties to successfully complete your simulation. If PRO/II has incomplete property information for a particular component, you can either "fill in the gaps" with established property prediction methods that are based on structural data or input your own component property data.

Note: As a general rule, if you have water in your system, it is wise to add it as the first component.


➤ Click the Component Selection button on the toolbar or select Input/Component Selection from the menu bar and select your components using the Component Selection dialog box.

Figure 8: Component Selection

Dialog Box

If you don't know the exact name or alias of a desired component, you can click and search through the available lists.


- List/Search Dialog Box

Components are listed alphabetically, and then by case. For example, the component ammonia (NH3) would be listed as H3N. Calcium would be listed as Ca, not CA.

Select from Lists...

22 Defining the Components

DatabanksThe PRO/II component library is actually a composite of several estab-lished databanks.

By default, PRO/II searches the PROCESS databank first and the SIMSCI databank second. All the components in the PROCESS data-bank are in the SIMSCI databank. To change the order in which PRO/II searches for your components, click in the Com-ponent Selection dialog box.

Petroleum Components

A component breakdown for petroleum-based streams, such as crude oil, is difficult to obtain, because they contain thousands of distinct com-pounds. Usually these hydrocarbon streams are characterized in terms of laboratory test data (known as assay data). This typically includes distil-lation data, gravity data, and an analysis of the low-boiling pure compo-nents (the lightends). PRO/II derives a set of petroleum components from this assay data by using industry standard characterization tech-niques. These derived components are used to model the streams given by assay data. This technique is discussed in the Process Stream chapter.

PRO/II allows you to enter individual petroleum components, which are represented as cuts or sections of a hydrocarbon stream with defined average boiling points, specific gravities, and other thermophysical prop-erties. You can define individual components as petroleum components by specifying at least two of the following three properties for each com-ponent:

■ Normal boiling point

■ Gravity

■ Molecular weight.

➤ Click in the Component Selection dialog box and enter the data.

➤ You can provide names for the individual cuts, or have PRO/II define names based on the cuts' NBPs.

Table 10: Pure Component DatabanksBank Description

PROCESS The PROCESS pure component databank.

SIMSCI The SIMSCI pure component databank.

DIPPR The AIChE DIPPR databank, available as an optional PRO/II add-on.

OLI The OLI databank, available as an optional PRO/II add-on.

bankid User databank, created and maintained using the Property Library Manager.

Databank Hierarchy...

Petroleum...


Typically, normal boiling point and gravity data are available to define petroleum components and assays. If you do not supply the molecular weight for a petroleum component, PRO/II uses a method developed by SIMSCI to estimate molecular weight. This method is most effective for components within the 300°F to 800°F boiling temperature range and is based on the Watson K-factor. In order to ensure accurate characteriza-tion, you should supply the molecular weight, especially if the PRO/II correlation range is not valid for your data.

PRO/II generates all other properties using methods in the API technical databook. You can select these methods or have PRO/II use default methods for all component properties required for the simulation. If you want to change the methods used, click the Assay Characterization but-ton on the toolbar or select Input/Assay Characterization from the menu bar, then click .

Petroleum components are useful in PRO/II simulations. Here are a few examples:

■ You should save petroleum components that have been characterized from assay data in a previous run, if you intend to run the simulation often, since this will reduce run time.

■ If you lack adequate assay data for environmental applications, you can choose to model heavy hydrocarbon contaminants as petroleum components.

■ Some companies process their own assay streams because they have proprietary procedures for calculating properties such as molecular weight. In this case, instead of entering assay data you can directly enter the petroleum components and any other proprietary thermo-physical properties (e.g., critical properties).

■ When simulating a process with primarily light hydrocarbons, you may want to use a petroleum component to represent all of the hydrocarbon components that are heavier than a certain defined component. This is often the case in gas processing applications where the majority of components are typically C5 or lighter.

Characterization Options...

Note: If you lump the heavy components of a mixture into a single petroleum component, you will most likely lose accuracy. Since the dew point is very sensitive to the heavy components in a mixture, the lumping together of heavy components should be minimized in simulations where the dew point is important.


User-defined Components

For the vast majority of PRO/II simulations, you will select components from the pure component library or define them as petroleum fractions. Occasionally you may want to use a component not in the PRO/II library. In this case you must supply all the properties that the simulation requires. These will depend on the needs of the thermodynamic system you select and the unit operations you use. For example, if you have a rigorous heat exchanger in the flowsheet you will need to supply trans-port property data.

➤ Click in the Component Selection dialog box and name your component.

➤ Click the Component Properties button on the toolbar and from the Component Properties dialog box open the Fixed Properties and Temperature Dependent Properties dialog boxes to enter the proper-ties (or to replace data for individual properties of a library compo-nent).

Figure 10: Component

Properties Dialog Box

Property PredictionWhether you are supplying a user-defined component or supplementing property data for an existing component, the quality of the results is sig-nificantly enhanced if you use reliable experimental data. If such data are insufficient or unavailable, you can access the property prediction capa-bilities of PRO/II. These estimation methods are valid for organic com-ponents that have molecular weights below 400 and fewer than 20 unique structural groups. Click in the Component Properties dialog box to select the component(s) you want filled then click to define the UNIFAC groups.

User-defined...

Fill from Structure...

UNIFAC Structures...


Solid Components

If some of your components exist in the solid phase you must identify them as solid, liquid-solid or vapor-liquid-solid.

➤ Click in the Component Selection dialog box.

By default, all non-library components are vapor-liquid. Solid library components default to the correct phase. All properties are entered in the same dialog boxes as for user-defined components.

If a component is molecular, you must enter its molecular weight. If it is a non-molecular component, it can exist in only the solid phase.

Particle size distribution is a property of a stream and is explained in the Process Stream chapter. However, you must first specify size intervals. Click on the Component Properties dialog box and enter distribution ranges.

Polymers Polymers are very high molecular weight, long-chain components made up of various combinations of monomer units with a recurring chemical structure. Using the optional Polymer add-on module, you can define the structure of polymer segments and specify how polymer components are constructed from these segments. The van Krevelen group contribution method is used to predict the thermophysical properties of polymers on the basis of the individual structural groups.

➤ In the Component Selection dialog box, click to define polymer components and polymer segments.

➤ Enter particle size distribution data for polymer components in the same way as for solid components. In the Component Properties dia-log box, click .

Table 11: Component Property Data Required for Solid Components

Property Solid Liquid/Solid Vapor/Liquid/Solid

Solid Specific Heat or Solid Enthalpy Required Required Required

Solid Density Required Required Required

Molecular Weight Conditional Required Required

Normal Melting Point Conditional Conditional

Heat of Formation (L or S) Conditional Conditional

Specific Gravity Required Required

Liquid Enthalpy Required Required

Liquid Density Required Required

Heat of Fusion Conditional Conditional

“Conditional” means that it may be required by some unit operations.

Component Phases...

Particle Size Distribution...

Polymer...

Distribution Functions...


Ionic Components

Electrolyte models are available in an optional add-on module to simu-late aqueous systems in a wide range of industrial applications. The models apply to fixed component lists with a pre-defined set of thermo-dynamic methods for K-values, enthalpies and densities.

Component Properties

Components in a PRO/II databank have a full range of properties. Com-ponent properties fall into six categories:

■ Fixed properties

■ Temperature-dependent properties

■ User Defined and Refinery Inspection properties

■ Solid properties

■ Polymer properties

■ Structure data

The pure component properties that you need to run a simulation may depend upon the selected thermodynamic method. The required proper-ties are listed for each method in the Thermodynamic Methods section of the PRO/II Reference Manual.

Following are a few of the most important data requirements:

■ With the exception of components declared to exist only as solids, all components must have a molecular weight and a specific gravity (which can be alternatively supplied as an API gravity or standard liquid density).

■ For calculations with an equation of state method (such as Soave-Redlich-Kwong or Peng-Robinson), PRO/II requires the critical temperatures and critical pressures of the components. Each compo-nent also requires either an acentric factor or a correlation for the equation's alpha parameter.

■ K-value calculations with liquid activity coefficient methods (such as NRTL and UNIQUAC) require pure component vapor pressures. Several of these methods also require other properties such as liquid molar volumes, solubility parameters, or van der Waals area and vol-ume parameters.

■ All enthalpy and entropy methods require ideal gas enthalpies for each component, with the exception of the Ideal and Johnson-Gray-son methods.


■ The Ideal method for liquid enthalpy requires the enthalpy of the sat-urated liquid. Use of this method for vapor enthalpies requires satu-rated liquid enthalpies, plus the latent heat of vaporization for each component. Ideal liquid densities require saturated liquid densities.

Again, in most cases, you do not need to worry about such requirements because the components retrieved from PRO/II's databanks will have sufficient data for any thermodynamic method.

Fixed Properties

To display the fixed properties of the selected components in your simu-lation, click in the Component Properties dialog box. Here, you can enter user-defined component properties or replace data for library components. Table 12 displays the sub-dialog box in which each property is located.

Table 12: Location of Fixed PropertiesProperty Dialog Box / Sub-Dialog Box

Acentric Factor Fixed Properties / Miscellaneous Properties

Carbon Number Fixed Properties / Miscellaneous Properties

Critical Compressibility Factor Fixed Properties / Critical Properties

Critical Pressure Fixed Properties / Critical Properties

Critical Temperature Fixed Properties / Critical Properties

Critical Volume Fixed Properties / Critical Properties

Dipole Moment Fixed Properties / Molecular Constants

Enthalpy of Combustion Fixed Properties / Miscellaneous Properties

Enthalpy of Fusion Fixed Properties / Miscellaneous Properties

Gibbs Energy of Formation Fixed Properties / Heats of Formation

Freezing Point (Normal Melting Point) Fixed Properties / Miscellaneous Properties

Gross Heating Value Fixed Properties / Miscellaneous Properties

Heat of Formation Fixed Properties / Heats of Formation

Heat of Vaporization Fixed Properties / Miscellaneous Properties

Hydrogen Deficiency Number Fixed Properties / Miscellaneous Properties

Liquid Molar Volume Fixed Properties / Miscellaneous Properties

Lower Heating Value Fixed Properties / Miscellaneous Properties

Molecular Weight Fixed Properties

Normal Boiling Point Fixed Properties

Rackett Parameter Fixed Properties / Miscellaneous Properties

Radius of Gyration Fixed Properties / Molecular Constants

Solubility Parameter Fixed Properties / Miscellaneous Properties

Specific Gravity Fixed Properties

Triple Point Pressure Fixed Properties / Miscellaneous Properties

Triple Point Temperature Fixed Properties / Miscellaneous Properties

van der Waals Area and Volume Fixed Properties / Molecular Constants

Fixed...


Temperature-Dependent Properties

You can enter the temperature-dependent properties given in Table 13below in either tabular or equation form. Extrapolation of temperature-dependent properties outside the user-defined temperature limits is per-formed linearly, except for vapor pressure and viscosity, which are extrapolated as ln(property) versus the reciprocal of the absolute temper-ature. These methods are also used for interpolation and extrapolation of tabular property data and for extrapolation of the temperature-dependent property correlations retrieved from PRO/II's databanks.

➤ Click in the Component Properties dialog box.

➤ Click the appropriate button to enter user-defined component proper-ties or to replace data for library components.

You can also view correlation coefficients and generate graphical plots of temperature dependent property data. These plots are displayed in the Plot Viewer. Each plot generated is shown in a new window, allowing multiple plots to be displayed simultaneously. PRO/II plots can be exported to other external applications (for example, Microsoft Excel).

➤ Select the Phase by clicking the appropriate button.

➤ Select Correlation Coefficients (default) and click to display the coefficients.

Table 13: Location of Temperature Dependent PropertiesProperty Button

Enthalpy of Vaporization

Ideal Vapor Enthalpy

Liquid Density

Liquid Thermal Conductivity

Liquid Viscosity

Saturated Liquid Enthalpy

Solid Density

Solid Heat Capacity

Solid Vapor Pressure

Surface Tension

Vapor Pressure

Vapor Thermal Conductivity

Vapor Viscosity

Temperature Dependent...

Enter Data...


Figure 11: Correlation Selection

Dialog Box

➤ To view a plot, click and select the type of plot you want. For example, Figure 12 shows a plot of the vapor pressure of butane.

Figure 12: Vapor Pressure of

Butane Plot

You can view the plot in any desired unit of measure.

View Curve...


Refinery Inspection Properties

You can enter global data for Refinery Inspection Properties by clicking in the Component Properties dialog

box. These global data will be used for all thermodynamic systems but can be overridden in each thermodynamic system.

A refinery inspection property will not be calculated unless a method is selected for it during thermodynamic data entry.

User-Defined Properties

You can enter global data for user-defined properties by clicking in the Component Properties dialog

box. These global data will be used for all thermodynamic systems but can be overridden in each thermodynamic system.

Solid Properties

All solid properties, fixed and temperature-dependent, are entered in the same dialog boxes as for user-defined components.

Polymer Properties

Click on the Component Selection dialog box to define polymer components and polymer segments. Enter particle size distribu-tion data for polymer components in the same way as for solid compo-nents. Click in the Component Propertiesdialog box to enter distribution function data for polymer components.

Structure Data Click in the Component Properties dialog box to define UNIFAC structures for selected components.

Accessing Property

Data with DATAPREP

Within PRO/II you are limited to examining either the fixed component properties given in the printout, or those which can be viewed through the Component Properties dialog boxes. However, DATAPREP provides you quick and total access to the PRO/II component database without having to set up and run a simulation. Using the menu-driven interface of DATAPREP, you can view fixed and descriptive properties as well as temperature-dependent properties in tabular and graphical forms for all the components in the PRO/II databanks. DATAPREP also contains the following pure component fixed properties:

■ Lower flammability limit

■ Upper flammability limit

■ Auto-ignition temperature

■ Flash point.

Refinery Inspection Properties...

User-defined Special Properties...

Polymer...




Furthermore, unlike PRO/II, DATAPREP gives information regarding the accuracy and source of the component data, as well as the tempera-ture limits for the temperature-dependent correlations.

DATAPREP also gives you the option of viewing properties for familiesof components. You can view this data as either tables or graphs. Figure 13 shows a plot of vapor pressure versus temperature for a family of alcohols. The axes have been set to plot vapor pressure (on a logarithmic scale) versus inverse temperature. The top curve corresponds to metha-nol, followed by ethanol, and then the remaining alcohols by increasing carbon number.

Figure 13: Vapor Pressure for

Family of Alcohols

Figure 14 further illustrates the type of graphical information that DATAPREP provides for pure library components. This graph com-pletely describes the range in enthalpy of water from the solid to ideal gas phase, and includes several distinct stages, which are described below:

1. The diagram starts at the bottom, far left, with the solid enthalpy curve.

2. The first vertical line (at the melting temperature) equals the heat of fusion and marks the transition from the solid to the liquid phase.

3. The liquid line then continues to the right until it reaches the critical temperature.

4. At the critical temperature the liquid enthalpy curve makes a contin-uous transition back to the left along the vapor line.

5. The vertical line connecting the liquid and vapor curves represents the heat of vaporization at the normal boiling point.

15 20 25 30 35 400.0001

0.001

0.01

0.1

1

10

100

1000

10000

(10E- 4)

(10E+ 3)

1/T (1/K)

VAPO

R PR

ESS

URE

(N/m

^2)

0 :METHANOL 1 :ETHANOL 2 :n-PROPANOL 3 :n-BUTANOL 4 :1-PENTANOL5 :1-HEXANOL 6 :1-HEPTANOL 7 :1-OCTANOL 8 :1-NONANOL 9 :1-DECANOL

54321

0

6

789


Figure 14: Enthalpy Curve for

Water

Component Data

Printout

In the Component Data section of the output file (.OUT), each compo-nent defined in the simulation is listed, along with its component and phase type, and nine associated fixed properties. These include: molecu-lar weight, API, NBP, critical temperature, critical pressure, critical vol-ume, acentric factor, heat of formation, and Gibbs free energy of formation.

-500 -250 0 250 500 750-80

0

80

160

240

320(10E+ 2)

Temperature F

ENTH

ALP

Y BT

U/lb

mol Heat of Vaporization

at NBP

Saturated Vapor Curve

Ideal Gas Curve

Critical Point

Saturated Liquid Curve

Solid CurveHeat of Fusion

at NMP

Enth

alpy

(Btu

/lb-m

ol)

(ºF)


Selecting the Thermodynamic Method

Selecting the appropriate thermodynamic method for your flowsheet is a critically important decision. Obviously, if you choose a thermodynamic system that cannot accurately model the phase behavior of the process, the simulation results will be invalid.

Inappropriate choice of thermodynamic model is the largest single source of error in process simulation and it is always a good idea to ver-ify your selection of a thermodynamic system by comparing simulation results with actual plant operating data. Since it is not possible to develop a single thermodynamic method to model all chemicals under all conditions, PRO/II uses several different models. Each works well in some situations and poorly in others. It is up to you to select the most appropriate methods for your particular flowsheet. Polar components at high pressure should not be simulated with a thermodynamic method that was designed to model low pressure hydrocarbons. Just because a computer reports convergence to great precision does not mean you should believe that the answers accurately model your actual process. Use your experience and engineering judgment to check that results are reasonable.

Properties and Systems

PRO/II offers numerous methods for calculating thermodynamic proper-ties. Generally you must select methods for calculating these thermody-namic properties:

■ Equilibrium K-values

■ Enthalpies

■ Entropies

■ Densities.

In PRO/II, thermodynamic methods are arranged into systems. When you choose a thermodynamic system, PRO/II will provide default meth-ods for each of these thermodynamic properties. You can override these defaults. For example, if the Soave-Redlich-Kwong thermodynamic sys-tem is selected, the default liquid density method is API. You can replace this with another method, for example, Lee-Kesler, should you feel Lee-Kesler will predict the liquid densities more accurately for your simula-tion.

➤ Click the Thermodynamic Data button on the toolbar or select Input/Thermodynamic Data... from the menu bar.

34 Selecting the Thermodynamic Method

➤ Click on a Category and choose a Primary Method from the selec-tion shown.

➤ Transfer your choice by clicking .

Figure 15: Thermodynamic Data Dialog Box

➤ To change a default, click in the Thermodynamic Datadialog box and make the desired changes.

Figure 16: Modification

Dialog Box

The thermodynamic methods available in PRO/II can be classified into seven categories:

■ Ideal methods

■ Generalized correlations

■ Equations of state

■ Liquid activity methods

Add ->

Modify...


■ Special packages

■ Electrolytes

■ Polymers.

Ideal MethodsIdeal methods calculate the mixture properties as weighted sums of the pure component properties. Each component's contribution is propor-tional to its quantity in the mixture. While ideal methods often provide good approximations for enthalpies and densities, more sophisticated methods are almost always required for K-values.

Generalized CorrelationsGeneralized correlations are empirical or semi-empirical methods, mostly based on the principle of corresponding states. They generally do not contain any adjustable binary parameters and are primarily useful for nonpolar hydrocarbon mixtures. Examples of generalized correlations include the Braun K-10 (BK-10) and Grayson-Streed (GS) methods.

Equations of State (EOS)Equations of state are mathematical expressions relating the density, temperature, pressure, and composition of a fluid. From an equation of state, you can calculate component K-values as well as the departures of enthalpy and entropy from their ideal gas values. Well-known examples of equations of state are the ideal gas law and the Van der Waals equa-tion. More modern equations of state include the Soave-Redlich-Kwong (SRK) and Peng-Robinson (PR) equations. These equations often involve the use of binary interaction parameters (usually denoted by kij) to account for interactions between different components. These param-eters can be:

■ Obtained from PRO/II's databanks or internal estimation techniques

■ Supplied by the user

■ Fit to experimental data.

The basic SRK and PR equations are useful for systems of nonpolar hydrocarbons; more sophisticated modifications are available to better represent systems containing polar components and to calculate rigorous vapor-liquid-liquid equilibrium.

Liquid Activity Coefficient Theory (LACT) MethodsLACT methods calculate K-values by starting with an ideal solution and correcting the result with activity coefficients. The activity coefficients are calculated from a model for the excess Gibbs energy of the liquid


mixture. The most commonly used methods are NRTL and UNIQUAC. Binary interaction parameters are usually necessary. They can be:

■ Obtained from PRO/II's databanks

■ Estimated using the UNIFAC method

■ Supplied by the user

■ Fit to experimental data.

Dissolved gases can be modeled with Henry's Law, and a heat of mixing option can be used to correct for nonideality in the liquid enthalpy. If the necessary parameters are available, LACT methods can successfully describe a wide variety of nonideal mixtures (particularly mixtures of components having similar volatility) including mixtures exhibiting two liquid phases.

Special PackagesPRO/II contains several special packages designed for thermodynamic calculations on specific systems. These include:

■ The Glycol package uses the SRKM method to calculate phase equi-libria for glycol dehydration applications.

■ The Sour package and the GPA Sour Water package were developed for sour water applications.

■ The Amine package can be used to model the removal of H2S and CO2 from natural gas streams using aqueous amine systems.

■ The Alcohol package uses the NRTL liquid activity method to calcu-late phase equilibria for systems containing polar compounds, such as alcohols and water.

ElectrolytesA special add-on of PRO/II is available for systems in which aqueous electrolyte chemistry is important. Consult your SIMSCI representative for further details.

PolymersThe polymers add-on provides special thermodynamic packages which are calculated by a variety of empirical methods including three activity coefficient K-value models using ideal enthalpy and density and two equations of state which predict all the required thermodynamic proper-ties.


Transport Property Methods

All simulations require selection of a thermodynamic method. Some also require transport properties, which are accessed through the Modifica-tion dialog box by clicking .

The unit operations that need transport properties are:

■ Column (hydraulics)

■ Pipe

■ Rigorous heat exchanger

■ Dissolver

■ Depressuring unit

■ Output tables.

Transport properties include:

■ Viscosity

■ Thermal conductivity

■ Liquid diffusivity

■ Surface tension.

Four calculation methods are available for computing transport proper-ties:

■ Pure

■ Petroleum

■ Trapp

■ User-defined.

The Pure option applies simple mixing rules to the temperature-depen-dent pure component values available in the selected databanks to calcu-late mixture transport properties. Saturation values are not pressure corrected. The Petroleum method uses predictive correlations, including pressure corrections, that apply to bulk hydrocarbon mixtures. The Trapp option uses a one fluid conformal model to calculate vapor and liquid viscosities and thermal conductivities for hydrocarbons; it uses the Petroleum method to calculate surface tension. The User-defined option allows you to provide up to five subroutines to compute transport proper-ties.

Transport Properties...


PRO/II provides a default method for each transport property when you select a transport method (except User-defined). You can choose to over-ride these methods if necessary. For example, you can select the API Technical Data Book liquid viscosity method to replace the default Pure liquid viscosity method. Refer to the PRO/II Reference Manual and thePRO/II Application Briefs Manual for selection of the proper transport property method.

Water Handling in

Hydrocarbon Systems

PRO/II can perform three-phase flash calculations for hydrocarbon-water mixtures. These calculations can be conducted either rigorously using VLLE thermodynamics or semi-rigorously using VLE thermody-namics with the water decant option.

Water Decant OptionThe free water option is a convenient, efficient method to simulate the three phase behavior of hydrocarbon-water systems. This option should be used when the solubility of hydrocarbons in the liquid water phase is small and not important for the simulation. There are two product streams: the first is a liquid hydrocarbon phase with dissolved water, the second is a free water phase. The free water phase contains no dissolved hydrocarbons or light gases. If the amount of dissolved hydrocarbons in the water phase is important (for example, an environmental compliance application), use a rigorous three-phase calculation, such as SRKM or SRKKD.

Using the free water option will result in a semi-rigorous three phase cal-culation. The vapor phase is saturated with water at a fixed pressure, and water is dissolved in the hydrocarbon liquid up to its solubility limit. Any remaining water is decanted as a pure water phase. PRO/II com-putes the solubility of water in the hydrocarbon-rich liquid phase using one of its three water solubility correlations:

■ SIMSCI (based on SIMSCI proprietary methods)

■ KEROSENE (based on the data for the solubility of water in kero-sene from API Technical Data Book Figure 9A1.4)

■ EOS (based on computing the water K-value with the equation of state as the VLE K-value method).

A pure water liquid phase is formed when the partial pressure of water reaches its saturation pressure at the flash temperature. Details of the cal-culation are given in the PRO/II Reference Manual.

➤ Click in the Modification dialog box to switch on water decanting and to select the solubility calculation method.

Water Options...


Rigorous Vapor-Liquid-Liquid Equilibrium (VLLE) CalculationsSome thermodynamic systems have the ability to model VLLE as well as VLE systems. PRO/II can perform rigorous three-phase equilibrium calculations using the FLASH unit if you select the VLLE option for such a thermodynamic system. Rigorous thermodynamic calculations can predict the existence and compositions of two immiscible liquid phases. In this case, the second product stream is designated as the second liquid phase.

For a hydrocarbon-water system, the water product stream is no longer pure, it does contain some dissolved hydrocarbon. This liquid water phase is considered as the denser of the two liquid phases.

A discussion on selection of the appropriate thermodynamic set for three-phase systems is given in the PRO/II Reference Manual.

Solid-Liquid Equilibrium

Solid-liquid equilibria can be used with all thermodynamic systems. The van't Hoff solubility method calculates solid-liquid equilibrium K-values for nearly ideal non-electrolyte systems. The solute and solvent should be of a similar chemical nature. Select this method from the K-value (SLE) list on the Modification dialog box.

Alternatively, you can enter solubility data correlated as a function of temperature. Select User-supplied Data from the K-value (SLE) list on the Modification dialog box, and click .

Precipitation of solid salts and minerals from aqueous solutions can be calculated rigorously using the PRO/II Electrolytes add-on module.

Application Examples

Table 14 shows some applications for the most common forms of ther-modynamic methods.

Enter Data...

Table 14: Thermodynamic Methods and Application ExamplesForm Application Examples of

Thermodynamic Method

Generalized Correlation

Low pressure crude systems involving heavy hydrocarbons: vacuum and atmospheric crude towers

BK-10, GS, IGS

Equation of State Light hydrocarbon systems, hydrogen-rich systems: reformers and hydrotreaters

SRK, PR

Liquid Activity Coefficient Method

Non-ideal chemical systems: aromatic/non-aromatic extraction, chemical systems with small amounts of supercritical gases

NRTL, UNIQUAC, NRTL with Henry's law


Because the accuracy of the simulation hinges largely on the selection of the correct thermodynamic method, you should exercise great care in choosing a method. Though these guidelines give advice on which ther-modynamic sets best suit which process systems, it is always advisable to check that the results of your specific simulation are reasonable.

Application guidelines are available in the PRO/II on-line Reference Manual, supplied on the distribution CD, or are accessible through the Help system. Alternately, in the Thermodynamics Data main dialog box, click on the toolbar to access the Help topic for that dialog box. Click on Application Guidelines on the first Help screen.

Multiple Methods

For some complex processes, you may need to use different thermody-namic systems for different sections of the flowsheet. PRO/II allows you to define multiple thermodynamic systems for use in a single simulation.

➤ Click the Thermodynamic Data button, which is now blue to show that you have already made a selection.

➤ Click on a Category, choose a second Primary Method from the selection shown, and click . Any method from any category is satisfactory.

➤ Do this for as many different methods as you wish.

You can then select any of these Defined Systems for use within any unit operation. If you do not make an explicit selection in a unit operation, the unit will use whichever system you designate as the default. Desig-nate the default by selecting from the drop-down Default System list on the Thermodynamic Data dialog box.

Using Multiple Methods

Using multiple thermodynamic systems within a single simulation pre-sents no complications when the materials flowing through the process are not mixed. For example, you might use different methods for the hot and cold sides of a HEAT EXCHANGER. On the other hand, if you are feed-ing a product stream from a unit operation that uses one thermodynamic system into a unit that uses a different system, you must be careful not to introduce discontinuities in the flowsheet.

For example, a stream at a known pressure whose temperature has been calculated from its enthalpy by the Soave-Redlich-Kwong equation of state is fed to a constant pressure adiabatic flash unit which uses Peng-Robinson as its thermodynamic set. If nothing is done, the adiabatic flash will calculate a different temperature from the enthalpy of the stream.

Overview

Add ->


To avoid this inconsistency and maintain the same stream temperature, insert a dummy isothermal "reset" unit which maintains the temperature and pressure but re-calculates the enthalpy using Peng-Robinson.

The adiabatic flash now receives a feed at a temperature, pressure and enthalpy consistent with the method it is using and there will be no dis-continuity. The difference between the two methods is represented by the duty of the “dummy” flash unit.

In this example it is appropriate to use a fixed temperature and pressure FLASH to reset the enthalpy. In other situations, you might need to spec-ify the reset FLASH to produce a bubble or dew point or a fixed liquid fraction. It is your responsibility to decide what stream characteristics need to be preserved in order to avoid errors in the downstream unit and to set up the reset FLASH accordingly.

L H*L

Set=PR

V H*V

F HF

Q = (V H*V + L H*L) - F H*F

Set=PR

Set=SRK

H*F

F

HF H*F≠

Insert “reset”flash unit


Supplying Process Stream Data

Streams and unit operations are the building blocks of a flowsheet. For each unit operation you must define at least one feed stream and at least one product stream. By defining the product from one unit operation as the feed to another, you establish the connections between the various units in the flowsheet.

Types of Streams

Even simple flowsheets can contain several different types of streams.

External Feed StreamsExternal feed streams originate outside the flowsheet. You must provide their thermal condition (e.g., temperature and pressure), their composi-tion, and their flowrate. The components in your feed streams can come from PRO/II's component library, from assay data, or from user-defined or petroleum components.

You do not have to worry about resetting external feed streams. PRO/II automatically flashes these streams prior to flowsheet execution. Each stream is flashed using the thermodynamic system associated with the unit it feeds. Other user-supplied streams, such as initial estimates for recycle streams, are also flashed to be consistent with the units they feed.

Internal Feed StreamsInternal feed streams are the product of one unit operation and the feed to another. Their properties are calculated by PRO/II and although you can provide data for their attributes these data will be overwritten by PRO/II as soon as the unit operation has solved.

Product StreamsProduct streams exit the unit. No data entry is necessary, for any attribute you provide will be overwritten by the calculated values.

InternalFeed

ExternalFeed

Product

Recycle

Product


Recycle StreamsRecycle streams are special internal feed streams that connect down-stream units to upstream units. PRO/II automatically recognizes recycle loops and adjusts its calculations appropriately. You can provide esti-mates for recycle stream properties to help accelerate the solution but it is not usually necessary and a poor estimate is usually worse than no estimate at all.

Recycle Convergence

PRO/II accomplishes recycle convergence by solving the flowsheet sequentially using iterative techniques. PRO/II's default iterative method is direct substitution. In this technique, the units are calculated sequen-tially many times. For example, if a recycle loop contains units A, B, and C, then the calculational sequence would be: A,B,C, A,B,C, A,B,C, ... Each pass through the loop constitutes an iteration. In the first iteration, the recycle stream has a flowrate of zero, unless you explicitly provide an estimate. At all other iterations, the recycle stream has the values that were calculated at the end of the previous iteration. The recycle loop has converged when the recycle stream changes are sufficiently small between two iterations. The magnitude of sufficiently small is deter-mined by the various recycle convergence tolerance parameters that PRO/II uses (you are free to provide these values).

You must be aware that iterative methods are usually not guaranteed to converge. Direct substitution, however, is fast and reliable for many problems, although it sometimes needs your help. If you can provide a good initial guess for a recycle stream, the loop is likely converge faster and more reliably.

Because of the greatly increased number of computations, converging recycle loops can require large amounts of time. For this reason, PRO/II provides two methods to accelerate convergence. These are the Wegstein and Broyden methods. As is typical with many iterative techniques, they work well for some problems and might not work at all for others. Both of these methods seek to accelerate the direct substitution method by providing better estimates of the recycle stream at each iteration. Accel-eration methods can often help with problems which tend to oscillate when using direct substitution alone or with problems which approach convergence asymptotically. These methods are described in more detail in the PRO/II Workbook, Flowsheet Control and Optimization.

Sequencing

Another way you can control recycle loop convergence is by specifying the calculation sequence. PRO/II provides three sequencing options:

■ The default method, Minimum Tear Streams, orders the calculations to minimize the number of tear streams. You can think of a tear

44 Supplying Process Stream Data

stream as a stream whose estimate you (or PRO/II) provide to break a recycle loop.

■ The Alternate method sequences the calculations roughly in the order that the units were entered. This was the default method in ver-sions earlier than PRO/II 3.30.

■ The Explicitly Defined by User method allows you to choose the ordering of the calculations.

Stream Properties

Before you enter data for a stream, you should have placed the unit oper-ations on your flowsheet and connected them together with feed, prod-uct, and recycle streams. You should also have declared the components that will be present in your simulation and specified the thermodynamic methods you want to be used.

To define a stream completely you must specify its:

■ Thermal condition

■ Composition

■ Flowrate

➤ To open the Stream Data dialog box, double-click on the stream, or right-click on the stream and select Data Entry from the menu.

Figure 17: Stream Data Dialog

Box


Thermal Condition

PRO/II requires that you provide the thermal condition for all external feed streams. You must also supply the stream thermal condition if you choose to enter a recycle estimate. To define the thermal condition, you must specify two of the following three properties:

■ Pressure

■ Temperature

■ Phase

Temperature and/or PressureFrom the First Specification drop-down list select either Temperature or Pressure. If you want to supply both, select Temperature here and Pres-sure as the Second Specification. Enter values in the fields supplied.

PhasePhase data are supplied as the Second Specification after you have sup-plied temperature or pressure. When defining the phase, you can specify the stream as one of:

■ a saturated liquid at its bubble point

■ a saturated vapor at its dew point

■ a mixed phase stream at a liquid fraction between 0.0 and 1.0, on a molar, weight or volume basis. Enter the value in the field provided.

For example:

If you do not define the phase, PRO/II will determine it with a phase equilibrium calculation at the specified temperature and pressure.


Composition and Flowrate

PRO/II requires you to specify the composition and flowrate of all exter-nal feeds and estimated recycle streams. You can enter the composition of a stream in one of four ways:

■ Using defined components

■ Using assay or distillation data

■ By referencing to another defined stream

■ By defining a stream as containing only solids

➤ Select the stream type in the Stream Type group box. You define the flowrate after choosing the stream type.

Compositional Stream

Compositional streams are made up of pure components: library, user-defined or petroleum. You must always provide the composition.

➤ Click to open the dialog box.

Figure 18: Flowrate and

Composition Dialog Box

If you select Individual Component Flowrates, PRO/II adds the individ-ual component flowrates to get the total rate.

If you provide a total stream flowrate, the sum of individual composi-tions entered should be 1.0 (fractions), 100 (percentages), or the flowrate that you supply. If not, check the Normalize Component Flowrates Based on Specified Fluid Flowrate box and PRO/II will adjust them for you.

If a component does not exist in a particular stream, enter a zero value for that component, or leave blank.

Flowrate and Composition...


Both composition and flowrate can be given on a molar, weight, standard liquid volume or standard gas volume basis. You can mix bases. For example, you can enter the total flowrate on a molar basis and enter the component rates on a weight basis.

To change the basis, click in the relevant field and click at the top of the dialog box.

Standard ConditionsIf you enter data on standard liquid or standard vapor volumetric bases, PRO/II will use the density of the phase you specify, regardless of the actual physical state of the stream at the specified thermal condition.

For liquid volume, PRO/II determines the molar flowrate using the liquid densities of the components at standard conditions (60°F and 1 atm). In cases where a component is a vapor at standard conditions, the estimated density value comes from the GPSA handbook. If the GPSA value is unavailable, PRO/II extrapolates from the density of the saturated liquid at atmospheric pressure.

For vapor volume, PRO/II uses the defined standard vapor conditions to determine the molar flowrate. The actual values of the standard tempera-ture and pressure (and therefore the computed flowrate) depend on the default units of measure that you are using. For the metric and SI sys-tems, STP defaults to 0°C and 1 atm of pressure. For English units, the STP default is 60°F and 1 atm of pressure. You can change the standard vapor conditions for your simulation using in the Default Units of Measure for Problem Data Input dialog box.

After determining the molar flowrate, PRO/II performs an internal flash to bring the stream from STP to the thermal condition that you have specified.

Petroleum Assay Stream

Assay streams differ from compositional streams by the way in which their compositions are entered and referenced. When you input an assay stream, instead of explicitly stating how much of each species is present, you provide simple experimental data. PRO/II uses that data to charac-terize the stream's composition in terms of petroleum components.

Typically, a laboratory-scale batch distillation analysis, such as the ASTM D86 procedure, is performed to characterize a crude stream.

UOM

Standard Vapor Conditions...


Generating Assay CurvesThe beaker is charged with the crude sample and heated. The tempera-ture increases as the lighter fractions boil out of the mixture. While the liquid is boiling, the temperature (T) and the total condensed volume (V) are periodically recorded, as are quantities such as gravity. Gravity data are commonly reported.

The quantities measured in this batch distillation experiment constitute the assay data for the sample. PRO/II then uses correlations to translate the assay data into TBP data from which all physical and thermody-namic properties are calculated.

The assay is represented as a plot of the temperature versus the cumula-tive percent distilled. PRO/II uses this distillation curve, along with an analysis of both the light pure components (e.g., propane, butanes, and pentanes) and the gravity data, to develop a set of petroleum components for the stream. These derived components are then used within the flow-sheet simulation to model streams that are characterized by assay data. PRO/II uses petroleum components in its internal calculations and can translate the simulation results back to assay data for output.

Thermometer

Condenser

Burner V

TTe

mpe

ratu

re

% Distilled


Assay Data Entry

➤ In the Stream Data dialog box, Select Petroleum Assay in the Stream Type group box. Click to open the dialog box.

In addition to the thermal conditions, you must provide:

■ Flowrate

■ Distillation Data

■ Gravity Data

Flowrate

➤ Enter a value in the field.

Figure 19: Flowrate

and Assay Dialog Box

Distillation Data

➤ Click to open the Assay Definition dialog box.

➤ Select a distillation type from the list:

● True Boiling Point (TBP)

● ASTM D86

● ASTM D1160

● ASTM D2887

Note that the D86 and D1160 data are almost always reported on a liquid volume basis while the D2887 data are always reported on a weight basis. Your flowsheet can include different types of assay streams (e.g., one stream on a D86 basis and another on a TBP basis).

If your distillations data has been collected at a pressure other than atmo-spheric (760 mm Hg), you must supply that pressure.

➤ Enter the data in the Percent Distilled vs. Temperature table.

Flowrate and Assay...

Define/Edit Assay...


Gravity Data

You must supply at least the average gravity for an assay stream, expressed as API gravity, Specific Gravity or Watson K-factor. If, in addition, you have a gravity versus percent distilled data curve, you should enter it for greater accuracy. Click to enter the data.

Figure 20: Assay Definition

Dialog Box

Optional Data

The following data are optional:

■ Light Ends Analysis

■ Molecular Weight Data

■ Refinery Inspection Properties and User-defined Properties

Light Ends Analysis

Often you can identify and accurately measure the quantity of a few of the lighter components that are present in the petroleum stream. You can supply their rate and composition in terms of library components. Such precisely measured data naturally improves the accuracy of the charac-terization. If the light ends are included in the average gravity of the stream, enter them here by clicking and entering the data. If the light ends are not included in the average gravity of the stream, enter them as a separate compositional stream and mix with the assay stream.

Gravity Curve...

Lightends...


Molecular Weight Data

If possible, you should provide measured molecular weight data because the molecular weight correlations are traditionally the least accurate of those used in hydrocarbon characterization. You can supply a molecular weight curve without supplying an average value by clicking

.

Refinery Inspection Properties and User-defined Properties

If available, you can include refinery inspection properties, such as cloud point, pour point, sulfur content, and kinematic viscosity, in assay form by clicking . To include custom-defined special properties, click .

Assay Processing MethodologyIn order for assay data to be useful in a flowsheet simulation, they must be converted to a discrete set of petroleum components. The flowchart in Figure 21 describes the procedure that PRO/II uses to interpret and trans-form the assay stream data into useful compositional information.

Figure 21: Assay Processing

Flowchart

This section explains the processing required to convert the assay data to its corresponding set of petroleum components.

Molecular Weight...

Refinery Inspection Properties... User-defined Special Properties...

Characterize OtherThermophysical Properties for

Pseudocomponents

Determine Average NBP, SPGRand MW for Pseudocomponents

Process Light Ends

Determine Moles, Mass andVolume for Each Cut

Distribute Assay Curveinto Cuts

Convert Data to Equivalent TBPCurve @ 760mm Hg

Distillation Data

Light Endsin Stream

Set ofPetroleum Components

Ass

ay P

roce

ssin

g St

eps


Convert Data to Equivalent TBP CurveAlthough ASTM assay data are much easier to obtain than TBP data, they are less valuable and must first be converted to 760 mm Hg true boiling point (TBP) curves. The next step is to fit the TBP data to a con-tinuous curve. This step is necessary because the supplied data points will not necessarily correspond to the desired cutpoints.

PRO/II offers three methods for interpolating distillation curves:

■ The default is the cubic spline method (known as the SPLINEoption). Cubic spline interpolation usually provides an excellent fit, however, instabilities can arise if the input data contain a large jump. Such jumps are usually the result of an error in your distillation data.

■ In the rare cases where a spline fit is unstable, PRO/II can interpolate the data using piecewise quadratic approximations (known as the QUADRATIC option).

■ The Probability Density Function (PDF) method is recommended when you suspect significant errors or random noise in your assay data. It differs from the SPLINE and QUADRATIC methods in that the curve is not required to pass through all of the supplied points. You can force the curve to pass through the initial and/or end points by using the Include in PDF option. This option has a strong effect on how incomplete distillations are extrapolated, and you are encour-aged to refer to the PRO/II Reference Manual before using it.

For incomplete distillations (i.e., distillations that do not range from 0 to 100% distilled), PRO/II uses the first two data points to extrapolate the TBP curve back to 0.01% volume and will similarly use the last two data points to extrapolate the TBP curve out to 99.99%. The extrapolation feature is particularly valuable for heavy ends distillations, which can terminate with over 50 volume percent of the initial charge not distilled.

Distribute Assay Curve into Cuts

As an option, you can define how to partition the TBP curve into discrete pseudocomponents, or cuts, by setting the desired number of compo-nents within a given temperature range. Table 15 lists the default cut-points used by PRO/II, when user-supplied cutpoints are not provided.

Table 15: Defining CutpointsTemperature Range Number of Components

100-800°F (38-427°C) 28

800-1200°F (427-649°C) 8

1200-1600°F ( 649-871°C) 4


Here, 28 pseudocomponents should exist in the temperature range 100-800°F; thus, these components each have a boiling range of 25°F. Note that the defaults in Table 15 were originally designed for partitioning crude oils. Material that boils below the first cut is combined with the first cut and material that boils above the last cut is combined with the last cut.

Determine Moles, Mass, and Volume for each CutBased on the sample's average gravity (or gravity curve, if you provided it), PRO/II calculates the number of moles, the mass, and the volume contained in each cut.

Process Light EndsHydrocarbon streams often contain significant amounts of light hydro-carbons. While there is no universal definition of light, hexane is a com-mon upper limit. Simulation of such systems is more accurate if these components are considered individually rather than lumped into pseudocomponents. PRO/II offers several techniques for processing your light ends:

■ Match to TBP Curve: By default, PRO/II will “match” your light ends data to the TBP curve. The rates for the light end components are adjusted up or down, all in the same proportion, until the NBP of the highest-boiling light end component intersects the TBP curve. PRO/II then discards all of the cuts from the TBP curve that fall into the region covered by the light ends data and uses the light end com-ponents in subsequent calculations.

■ Fraction of Assay: This method allows you to specify that the total light ends flowrate be a prescribed fraction (or percent) of the overall stream flowrate.

■ Use Compositions as Actual Rates: Here the compositional entries are used as the actual component flowrates. The total light ends flowrate is the sum of the individual components. The flowrates are not scaled to match the TBP curve.

■ Light Ends Rate: Here you provide the total light ends flowrate and the individual light ends components are given as fractions or per-cents. If your individual component values do not sum to 1 or 100, you can use the normalize component flowrates option.

Figure 22 shows graphically how the petroleum components are gener-ated and how the light ends data are matched to the assay curve.


Figure 22: Light Ends Matching

Determine Average NBP, SPGR, and MW for each PseudocomponentOnce PRO/II has defined the cuts in terms of moles, mass, and volume, and incorporated the light ends, it determines the normal boiling point (NBP), specific gravity (SPGR), and molecular weight (MW) for each cut.

Computing the Normal Boiling Point

PRO/II determines the NBP for each pseudocomponent as a volume or weight fraction average by integrating across the cut range:

(1)

x represents the percent liquid volume or weight distilled in cut j. PRO/II uses these average boiling points as correlating parameters when calcu-lating other thermophysical properties for each pseudocomponent.

Computing Average Gravity

If, in addition to the required stream average gravity value, you have entered a gravity curve, PRO/II will calculate the average gravity for each cut. If you supply only the average gravity for the stream, then PRO/II uses the Watson-K factor to calculate the average gravity for each cut. As you may recall, the Watson-K factor is a function of NBP and specific gravity:

(2)

NBPj

T x( ) xdxmin

xmax

∫xmax xmin–----------------------------=

K NBP1 3⁄

spgr-------------------=


Using the average NBP and average gravity for the stream, PRO/II com-putes a Watson-K factor for the entire stream. The Watson-K factor is a measure of the paraffinicity of a stock. The factor is relatively constant through the entire boiling range of crude oils, so computing one factor for the entire stream is a valid assumption. PRO/II then uses the Watson-K factor and the NBP for each cut to back-calculate each cut's average gravity as illustrated in Figure 23, where:

(3)

Computing Molecular Weights

As the next step in characterizing the pseudocomponents, PRO/II deter-mines the molecular weight using a correlation that relates it to NBP and gravity. Keep in mind that PRO/II's molecular weight correlations tend to be biased toward crude oils. Whenever possible, you should supply molecular weights to obtain a more accurate set of components. You can supply a molecular weight curve and, if available, an average value. If you supply both a curve and an average value, the average takes priority and the curve will be adjusted and extrapolated to match the average.

Figure 23: Computing the

Component NBP's and Gravities

spgrj

NBPj1 3⁄

K---------------------=

First, Integrateto Get NBP’s . . . .

Volume % Distilled

Tem

pera

ture

API

Gra

vity

Ligh

t En

ds

1st

Cut

2nd

Cut

3rd

Cut

. . . .Then Use Watson K Factor to Compute Midpoint Gravity for Each Cut.

Percent Distilled


Characterize Other Thermophysical Properties for the Pseudocomponents

All other physical and thermodynamic properties (e.g., critical properties and enthalpy curves) required by PRO/II can be calculated from the molecular weight, the NBP, and the gravity data by using correlations. To change methods for property estimation, curve fitting and intercon-versions, click and make the appropriate selections in this dialog box (Figure 24).

If the default correlations do not adequately match your specific assay data, you can try other calculation options to improve the fit. For more information on characterization options, refer to the PRO/II Keyword Manual and the PRO/II Reference Manual.

Figure 24: Assay

Characterization Options

Set of Petroleum ComponentsYou now have a set of petroleum components, which define the assay stream's composition and can be used in the simulation. You may be wondering if there is any relationship between the petroleum compo-nents discussed earlier in this chapter and the petroleum components generated from an assay. The answer is a definite Yes. A petroleum com-ponent, whether defined as part of a compositional stream, or generated by PRO/II's assay processing machinery, is treated the same by PRO/II.

In this discussion we have only considered deriving a set of petroleum components from one assay stream. In reality, multiple streams are often used to generate a component set. The blend option allows you to gener-ate more than one set of petroleum components from multiple streams within a given run. This is a powerful feature for modeling a process that has different feedstocks, particularly one that uses both virgin and cracked feedstocks.



Controlling Assay ProcessingYou can control how PRO/II processes your assay data by clicking the Assay Data button on the toolbar. In this dialog box (Figure 25), you can:

■ Modify the primary cutpoint set.

■ Add, modify and delete a secondary cutpoint set.

■ Nominate a cutpoint set to be used as the default for stream assay processing. To do this you must have defined at least one secondary cutpoint set.

Figure 25: Assay Cutpoints and

Characterization Dialog Box

Then, in the Flowrate and Assay dialog box, entered from the Stream Data dialog box, you can select the cutpoint set to use with this stream. Click on the default set of TBP cutpoints in the linked text and select the Secondary Cutpoint Set of your choice.

Reference Stream

A reference stream is a feed stream whose attributes are defined in terms of another stream (the referenced stream). The two streams have the same composition and can have the same rate (molar), temperature, and/or pressure.

➤ Select Referenced to Stream in the Stream Type group box and click the to open the dialog box.

Figure 26: Reference Stream

Dialog Box

Flowrate and Stream...


Typically, when using this option, you transfer the composition of one stream (the source) to another (the target) while overriding the molar rate, temperature, and/or pressure. You may find the reference stream feature most useful when the stream rate, temperature, and/or pressure change, but the composition remains the same. Such is the case in a ther-mal recycle. Figures 27 and 28 illustrate how a reference stream is used to break a thermal recycle, which occurs in natural gas processing plants where the cold separator gas is back exchanged with the warm feed to the chiller.

Figure 27: Thermal Recycle

Occurring in Natural Gas Processing

PRO/II will attempt to sequentially solve the flowsheet in Figure 27. Since the recycle stream (stream 5) has no calculated value, PRO/II will set the rate of the recycle stream entering HX-1 to zero and perform a one-sided heat exchanger calculation before advancing to HX-2. Taking this approach, PRO/II must complete three iterations or recycle passes to solve the flowsheet.

For a more efficient approach, you can rearrange the flowsheet by refer-encing stream 4X to stream 2. This will result in the resequencing of the PRO/II execution, and a new problem setup emerges as depicted in Fig-ure 28. Because stream 4X is now an external feed, its thermal condition must be provided. In this case, you can deduce temperature and pressure from other flowsheet parameters. The temperature of stream 4X is the same as the outlet temperature of HX-2, and the pressure is the pressure of stream 2 less the cumulative pressure drop across the two heat exchangers.

PRO/II can now solve the broken-recycle flowsheet, shown in Figure 28, in a single pass.


Figure 28: Breaking the Thermal

Recycle Using a Reference Stream

Clearly you can only apply the reference stream concept when the com-position of the source stream being referenced is available in the flow-sheet. In the example given above, the composition of stream 2 is known prior to the calculation of FLASH DRUM D-1 with a reference stream.

Another common usage of reference streams in a thermal recycle is shown in Figure 29. The feed to the distillation column is preheated by the column's bottom product. Most preheat systems have controllers, known as trim heaters, that maintain a desired column feed temperature; thus, this loop can be broken without corrupting the flowsheet solution. In Figure 27, HX-2 is a trim heater.

You can use a reference stream to set up the column feed at the desired temperature. This serves to decouple the column from the preheater and allows PRO/II to solve the column and preheater sequentially. The required flowrate of stream 5 is calculated after the column is solved. All recycle calculations have been eliminated.

Note: You can use a reference stream to break any thermal recycle where a trim heater or cooler is used to set a desired thermal condition in a flowsheet.

Note: Each time a source stream is updated, the target stream is also updated. For this reason, you should generally not use refer-ence streams to provide recycle estimates. If the source and tar-get streams are part of the same or nested recycle loops, PRO/II will reset the target stream on each pass through the loop. Nonconvergence of the flowsheet is likely to occur. How-ever, if the source stream is fixed (i.e., an external feed) using a reference stream as a recycle estimate will not cause conver-gence problems.


Figure 29: A) Distillation Column with Thermal Recycle

for Preheating Feed and B) Breaking the

Thermal Recycle Using a Reference

Stream

At times you may want to use one set of stream properties in several places. Though PRO/II does not allow you to use the same stream name to feed multiple units, it does offer these time-saving techniques:

■ Input the feed stream once and then reference the other feed streams to the original.

■ Input the feed stream once and then use the stream copy feature to define all others feed streams.

There is an important distinction to be made between a reference stream and a stream that has been defined using the copy feature. If you change the original feed stream, every stream that references it will also change. This is not true for a stream that has been copied. The original stream and its copy are totally disconnected after the copy has been made.

Solids Stream All streams can contain solids but there are some streams which contain only solids. These are handled differently in PRO/II. Solids-only streams contain only components which have been defined as solid components on the Component Phase Selection dialog box, accessed from the Com-ponent Selection dialog box.

➤ In the Stream Data dialog box, select Solids Only Stream in the Stream Type group box. Click . The Stream Data - Solid Components dialog box appears (Figure 30).

➤ Click the appropriate to enter molar- or weight-based solids flowrate and composition. Solid components which do not have molecular weight defined can be entered only on a weight basis.

(A) (B)

Stream Solids Data...

Enter Data...


Figure 30: Solid Components

Dialog Box

Polymer Stream

With the exception of reference streams, you can describe attributes of polymer components in any stream. You must first define at least one polymer component in the Definition of Polymer Components dialog box, accessed by clicking in the Component Selection dialog box. You must also supply distribution data for that component by click-ing in the Component Properties dialog box.

Then, in the Stream Data dialog box, click and enter Molecular weight/Moment distributions, particle size distribution and general attributes as appropriate.

Stream Utilities

PRO/II provides several utilities for obtaining stream properties and for creating and copying streams. In this section you will learn why these features are useful and how to use them. These include:

■ Flash and BVLE hotkeys

■ Copying streams within the same flowsheet and between different flowsheets

Hotkeys The PRO/II toolbar contains two buttons that allow you to calculate stream and thermodynamic properties at any time. These options are also accessible through the Tools menu.

The flash hotkey flashes the selected feed stream (or recycle estimate) at its specified conditions. Simply select the stream and click the flash hot-key button. A window displaying the temperature, pressure, composi-tion, and molar flowrate of each phase will appear. The flash hotkey also reports the stream's molecular weight and heat capacity. The flash hot-key is useful in the following circumstances:

■ To find the component molar flowrates of a stream that was entered on a volumetric or weight rate basis.

Polymer...


Stream Polymer Data...


pres-

own

airseffi-era-LE

r pres-

.

/or

eedtream

2 and

ste it

-se.

■ To determine the phase(s) of a stream with known temperature, sure, and bulk composition

■ To determine the temperature, or pressure, of a stream with knpressure, or temperature, and liquid fraction.

The BVLE hotkey graphically presents phase equilibrium data for pof components. Figure 31 shows a sample. It also plots activity cocients, fugacity coefficients, K-values, and compositions versus tempture, pressure, and composition. To view the graphs, click on the BVhotkey and enter the desired component pair and the temperature osure. As with any other graphic in PRO/II, you can copy the resultingplots to the clipboard and paste them into reports, spreadsheets, etc

Figure 31:Sample BVLE Plot

CopyingStreams

PRO/II allows you to copy streams within the same flowsheet andbetween different flowsheets.

Copying Streams Within the Same FlowsheetSuppose you want to copy the properties of feed stream S1 into fstream S2, a stream in the same flowsheet. To do so, simply select sS1 and press <CTRL+C> to copy the stream. Then select stream Spress <CTRL+V> to paste. All of S1's properties will be copied tostream S2. These functions also exist on the Edit menu.

To copy the properties of a product stream, copy it as before, but pausing the Paste Special command on the Edit menu.

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, Note: PRO/II cannot copy petroleum components that were generated from assay data (as opposed to petrocomponents whoproperties you explicitly enter) from product into feed streams


Copying Streams Between Different FlowsheetsPRO/II's Stream Data Link feature lets you transfer stream data betweensimulations. It establishes a link between a stream in the active simula-tion and a stream in another simulation database, allowing you to copydata from the other database to your open simulation. Unlike the refer-ence stream feature, this link is not dynamic, i.e., the target stream is notupdated automatically every time the source stream changes. The dataare copied only when you select the Update Stream Data Links com-mand from the Input menu, or when you activate the Update Now box inthe Define Stream Data Link dialog box.

Assume that flowsheet APP1.PRZ contains a stream, S1, that you want tocopy into another simulation. Run and save APP1 so that the properties(calculated or entered) of S1 are stored in the APP1 database files.

To copy stream S1 from APP1.PRZ into stream S2 in flowsheetAPP2.PRZ:

➤ Open or create APP2.

➤ Select stream S2 and choose Input/Define Stream Data Link from themenu bar.

➤ Check the Define Link box and enter the name of the database filethat contains the desired stream, APP1 in this example. Or, click

to search for the simulation.

➤ Enter the name of the stream that you would like to copy, S1 in thisexample. Or, use to search the stream names.

➤ If you want to copy S1 into S2 now (update the data link), check theUpdate Now box, and click . If you want to wait before transfer-ring the data, simply click .

PRO/II copies only those components that are common to both flow-sheets. Assume, for example, that S1 contains 10 mol/hr of methane, 5mol/hr of ethane, and 20 mol/hr CO2. If flowsheet APP2 does not haveCO2 in its list of defined components, then a data link between S1 andS2 will result in S2 containing 10 mol/hr of methane and 5 mol/hr ofethane. The CO2 is not copied. PRO/II will warn you of this situation.

Browse...

Browse...

OK OK

Note: The stream data link does not allow you to copy assay data andpetroleum components that were generated from assay data.


Supplying Process Unit Operations Data

PRO/II is a sequential modular simulator. Each unit is calculated sepa-rately with the calculations proceeding in a stepwise fashion from one unit to another.

PRO/II uses the unit operations concept to construct the flowsheet. You must define the unit operating conditions, e.g., the outlet temperature of a heat exchanger or the reflux ratio for a column.

Categories PRO/II offers a complete suite of unit operation calculations as shown Table 16 below.

Table 16: PRO/II Unit OperationsUnit Operation Description

Phase Change

Flash Calculates the thermodynamic state of any stream by performing phase equilibrium calculations when two variables are given.

Flash with Solids This is identical to the standard flash except that solid components are allowed in the calculation.

Stream Manipulation

Mixer Combines two or more streams into a single stream.

Splitter Splits a single feed or a mixture of feeds into two or more streams of identical composition and phase.

Stream Calculator Blends any number of feed streams and produces products with defined composition and thermal condition. New streams can also be created.

Columns

Distillation Column Splits feed stream(s) into streams of different composition based on temperature and pressure.

Side Column Includes both sidestrippers and siderectifiers.

Batch Distillation Simulates a batch rectifier comprising a stillpot, column, condenser and accumulator.

Pressure Change

Compressor Compresses the feed stream according to given specifications.

Expander Expands a stream isentropically to the specified conditions and outputs work during the process.

Pump Increases the pressure of a process stream to the required value.

Pipe Calculates single or mixed phase pressure drops through piping between unit operations. It can also determine the line size required for a given maximum pressure drop or minimum outlet pressure.

Depressuring Unit Simulates the time-pressure-temperature relationship when depressuring a vessel through a relief or control valve.

Valve Simulates the pressure drop across a valve.


Unit Operation Description

Heat Exchangers

Heat Exchanger Heats or cools a single process stream, exchanges heat between two process streams or between a process and a utility stream.

Rigorous Heat Exchanger

Calculates the temperature change, pressure drop, and heat transfer coefficients on both the Shell and Tube side of a rigorously defined Heat Exchanger, based upon the user-supplied exchanger geometric details.

LNG Heat Exchanger

Simulates the exchange of heat between any number of hot and cold streams. It is used for cryogenic cooling in the natural gas and air separation industries and can achieve close temperature approaches.

Reactors

Conversion Reactor Simulates a chemical reactor by solving the heat and material balances based on supplied reaction stoichiometry and fractional conversion.

Equilibrium Reactor Simulates a chemical reactor by solving the heat and material balances based on supplied reaction stoichiometry and reaction equilibrium data.

Plug Flow Reactor Simulates a tubular chemical reactor by solving the heat and material balances based on supplied reaction stoichiometry and kinetic data.

CST Reactor Simulates a chemical reactor by solving the heat and material balances based on supplied reaction stoichiometry and kinetic data. The Boiling Pot reactor is a continuous stirred tank reactor where all reactions take place in the liquid phase and only a single vapor product is allowed.

Gibbs Reactor Simulates a chemical reactor by solving the heat and material balances based on minimizing the free energy of the components in the reaction. Stoichiometry is not required.

Polymer Reactors Models either a continuous stirred tank reactor or a plug flow reactor for polymer systems with several different kinetic models.

Batch Reactor Simulates the operation of a batch or semi-batch reactor as a non-steady state operation.

Utilities

Phase Envelope Generates phase envelopes for multi-component streams using the Peng-Robinson or Soave-Redlich-Kwong equations of state.

Heating Curves Generates heating or cooling curves which represent a composite of equilibrium flash calculations, for any process stream or an unit operation internal stream.

Block Diagram Allows you to organize flowsheets into a hierarchical structure. One or more unit operations on a flowsheet can be grouped into a single icon, simplifying the main flowsheet.

Stream Properties Creates a stream property table which lists various properties for the selected streams.

Solids Handling

Solid Separator Separates the solid phase material from a mixture of feed streams.

Crystallizer Models the transformation of a supersaturated solution into a solid/liquid mixture phase.

Dissolver Models the dissolution of crystals into the liquid solvent phase from a mixture of feed streams.

Wiped Film Evaporator

Separates solvents and/or monomers from a polymer melt. A wiped film evaporator should be used when the removal of volatiles from a viscous polymer melt is diffusion limited.

Gas/Solid Cyclone Provides the capability to separate solid phase material with a specified particle size distribution from vapor streams.

Table 16: PRO/II Unit Operations

66 Supplying Process Unit Operations Data

Common Features of

all Unit Operations

All unit operations have some common features:

■ Unit identifier and a description. The unit identifier identifies the unit within the PRO/II calculations and is used in sequencing and specifications. PRO/II supplies identifiers for you automatically. However, you can override them, or have PRO/II prompt you for a name when adding the unit to the flowsheet.

■ Multiple feeds

■ Thermodynamic options

■ Product phases

Multiple Feeds

You can supply any number of feeds to a unit. Exceptions to this rule are highlighted when the unit operation is described.

When you do not provide a unit's pressure, PRO/II sets it to the lowest feed pressure and PRO/II mixes all feeds adiabatically at this pressure.

Thermo Options

If you have defined more than one thermodynamic system for your sim-ulation, you can specify which of the defined thermodynamic systems is to be used for the calculations of a specific unit operation. Select the thermodynamic system from the list of available choices within the unit operation.

Unit Operation Description

Flowsheet Manipulation

Controller Adjusts an upstream parameter in the flowsheet to reach a specified objective on a process stream, unit or thermodynamic parameter operation.

Multi-variable Controller

Adjusts a group of at least two or more upstream parameters in the flowsheet to reach a specified set of two or more objectives on process streams, units or thermodynamic parameter operations. There must be an equal number of specifications and variables.

Flowsheet Optimizer Either minimizes or maximizes an objective function by varying a number of flowsheet variables subject to a number of constraints while at the same time meeting a number of specifications.

Calculator Computes a result or an array of results for printout, allows you to assign results to a stream vector or for use by other unit operations.

User-Added Unit Allows access to your own FORTRAN calculational routines if you have obtained the PRO/II User-added Unit Operation supplement for PRO/II.

SIMSCI Add-Ons Allows access to SIMSCI Add-On calculational routines that are available within the standard version of PRO/II. This unit also allows access to optional calculational routines provided by SIMSCI if you have requested and installed the proper PRO/II upgrade package.

Table 16: PRO/II Unit Operations


The default system used for the thermodynamic calculations within indi-vidual unit operations is that selected as Default System in the Thermo-dynamic Data dialog box.

If the default system is changed, unit operations that have the default choice selected for their thermodynamic method calculations will auto-matically use the new default system

For unit operations that have an alternative thermodynamic system selected, changing the default system in the Thermodynamic Data dialog box will not change the thermodynamic method used within that unit operation.

Product Phases

Most unit operations allow you to split the product into one or more streams. You can assign the following phases to product streams:

■ Vapor

■ Liquid

■ Solid

■ Decanted Water

■ Second (heavy) Liquid

■ Vapor + Liquid (Mixture)

Exceptions to this rule are:

■ Simple heat exchanger—the rule applies to both sides of a simple HX.

■ Rigorous heat exchanger—the rule applies to both sides of a rigor-ous HX

■ LNG exchanger—the rule applies to all cells of an LNG exchanger

■ Plug flow reactor—the rule applies to both the reaction side and the heat exchange side

■ Flash—has to be the flash with solids to have a solid phase

■ Pump—only one product allowed

■ Depressuring—as many products as there are time intervals

■ Wiped film evaporator—bottoms has polymer melt (with less vola-tiles than the feed). Overhead is vapor stream containing volatiles that were removed.


■ Solid units—one solid and one liquid (with or without solids); or one solid and one gas (with or without solids)

■ Batch units—as many products as required by the process

Flash Calculations

When you perform design calculations or troubleshoot a process, you may need to know a mixture's phase behavior at certain process condi-tions, or you may need to know what conditions are necessary to recover a certain amount of a component from a mixture. Usually you must rely on a process simulator to get this type of information.

Flash Unit Operation

Figure 32 shows a general schematic of the PRO/II FLASH unit for a vapor-liquid system. PRO/II allows up to three products for this unit and an unlimited number of feeds.

Figure 32: Three-Phase

Equilibrium Flash Unit Operation

Note that Fj denotes the feed streams, V denotes the vapor product, L denotes the liquid product, W denotes either the decanted water or the second liquid product, and zji, yi, x1i, and x2i denote the component mole fractions for the respective streams. Q denotes the duty added or removed from the flash unit operation.

Solution ApproachFor simplicity, consider a common special case of the above configura-tion: a flash with a vapor product and a single liquid product. PRO/II uses an iterative approach to solve the mass and energy balances and equilibrium relationships for a given system. For a general two-phase flash, these equations are:

Total Mass Balance

F = V + L (4)

Component Mass Balances

Fzi = Vyi + Lxi i = 1,...,N (5)

F1, z1i

FM, zMi

V, yi

L, x1i

W, x2i

Q


Equilibrium Relationships

yi = Ki (T, P, yj, xj) xi i, j = 1,...,N (6)

Summation

i = 1,...,N (7)

Heat Balance

FHf + Q = VHv + LHl (8)

In equations (5) - (7), N is the number of components. Note, there are 3N+6 unknowns in this set of equations (F, V, L, zi, xi, yi, Q, T, and P). However, there are only 2N+3 equations, leaving N+3 variables that must be set. We will discuss how these variables are set in the next sec-tion.

For a bubble point flash, the liquid phase component mole fractions (xi) equal the component feed mole fractions (zi). Additionally, the amount of vapor (V) is equal to zero. Thus, the equilibrium relationship to be solved is:

i = 1,...,N (9)

Similarly, for a dew point flash, the amount of liquid (L) is equal to zero and the vapor phase component mole fractions (yi) equal the component feed mole fractions (zi). Thus, in this case the equilibrium relationship to be solved is:

i = 1,...,N (10)

The PRO/II Reference Manual provides details about the solution algo-rithm. PRO/II allows you to provide estimates of temperature or pressure in order to enhance convergence of the flash algorithm for all types of flashes except isothermal flashes.

Defining the Flash CalculationFrom the set of equations given above, you can see that Eq. (6) sets the phase equilibrium behavior for the system. In Eq. (6) the phase equilib-rium ratios or Ki's (also referred to as K-values) are typically functions of temperature, pressure, and composition, making the problem fairly complex. Your selection of a thermodynamic system for the process will greatly affect the solution.

As previously discussed, there are N+3 variables to be specified for each calculation. The feed stream composition and rate comprise N+1 of these variables. This leaves two degrees of freedom to be set in the flash algorithm. You must specify either the flash temperature or pressure.

yi xi

i∑–

i∑ 0=

Kizii∑ yi

i∑ 1.0= =

zi Ki⁄i∑ xi

i∑ 1.0= =


Valve, Mixer, and Splitter

Unit Operations

The VALVE, MIXER, and SPLITTER units also perform phase equilibrium calculations. They are each equivalent to an adiabatic flash with zero enthalpy change (duty=0). The temperature is always computed rather than specified, and PRO/II allows an unlimited number of feeds to these units. You can set the pressure or pressure drop; otherwise PRO/II assumes a pressure drop of zero and uses the lowest feed pressure for the product streams. Figures 33-35 depict the schematics for these unit oper-ations.

Figure 33: Valve Unit Operation

The VALVE unit can have up to three products. Designation and handling of the products for the VALVE unit is as flexible as for the FLASH unit. MIXER units can only have one product; however, PRO/II always deter-mines the product phase, regardless of which phase (V, L, W, or M) you designate.

Figure 34: Mixer

Unit Operation

Figure 35: Splitter Unit

Operation

The SPLITTER unit combines any number of feed streams and splits the combined feed into products of identical composition and thermal condi-tion. The same phase designation must be used for all products (i.e., liq-uid, vapor, etc.). If you select an incorrect phase designation, PRO/II will reset it to the correct phase, as with the other equilibrium calculation units.

In addition, you must define the stream rates using generalized stream specifications for all but one of the desired products. The SPLITTER unit allows only rate dependent stream specifications. For example, the rate of a component or group of components in a product is a rate dependent specification. The recovery of a fraction of the total feed to the splitter is also a rate dependent specification.

F1, z1i

Fn, zni

V, yi

L, x1i

L2, x2i

F1, z1i

Fn, zni

Fo, zoi

F 1, z 1i

F n, zn i

F o1, zo1i

F o2, zo2 i

F om , zom i


Flash Types This section describes the different flash types modeled in PRO/II.

Dew and Bubble Point FlashesFor dew point and bubble point flash calculations, you can designate a pseudo-stream product. This pseudo-stream is in equilibrium with the actual product stream, but does not actually exist. The default rate of the equilibrium pseudo-stream is zero, but you can arbitrarily set its rate using the Define feature within the FLASH unit, or enter a rate directly.

For a bubble point FLASH, the product is a saturated liquid, defined as the liquid product and the pseudo-stream is a saturated vapor, defined by the vapor product.

For a dew point FLASH, the product is a saturated vapor, defined as the vapor product and the pseudo-stream is a saturated liquid, defined by the liquid product.

Defining pseudo-streams can help solve flowsheets in many ways. For instance, suppose that you are given the composition and flowrate for the liquid distillate and reflux of a column; but, you only have the flowrate of the off-gas and not its composition. You can create the off-gas stream by feeding the liquid distillate to a bubble point FLASH and setting up a vapor pseudo-stream with a defined rate that is equal to the known off-gas rate.

Another useful calculation that you can perform with the dew point and bubble point FLASH units is the determination of the "latent heat" of a mixture. To find this quantity, the mixture must be transformed from a saturated liquid to a saturated vapor. The heat required for this phase change is the "latent heat," which is calculated as the difference between the mixture enthalpies at the bubble point and at the dew point at con-stant temperature. Keeping the temperature constant will eliminate sen-sible heat effects in the calculation.

Water and Hydrocarbon Dew Point FlashesThe water dew point of a water-hydrocarbon mixture is the operating condition at which the first drop of free water is formed as the mixture cools (or as the mixture's pressure is raised). Likewise, the hydrocarbon dew point is the operating condition at which the first drop of liquid hydrocarbon is formed.

In PRO/II, the standard dew point calculation finds the first dew point for a mixture. For water-hydrocarbon mixtures with hydrocarbons more vol-atile than water, this is also the water dew point. For water-hydrocarbon mixtures with hydrocarbons less volatile than water, this is also the hydrocarbon dew point. These dew point calculation options are avail-able in PRO/II for water-hydrocarbon systems that are modeled using the


water decant option. For the standard dew point calculation, PRO/II allows only a vapor product (V) and a liquid phase pseudo-stream (L). However, the hydrocarbon dew point option allows for a free water prod-uct (W), since the water may condense before the hydrocarbon, while the water dew point option allows for a liquid hydrocarbon product (L), since the hydrocarbon may condense before the water. PRO/II does not generate pseudo-streams for these optional dew point calculations.

Entrainment PRO/II can model the entrainment of one product phase in any other product phase. PRO/II performs the entrainment calculations after the FLASH unit converges. This makes the final product streams different than the flash specifications and not in equilibrium with each other.

Defining Reaction

Data

Reactor unit operations in PRO/II use the reaction data capability. Click the Reaction Data button on the toolbar to define the reaction data prop-erties. You assign names to individual reactions and store groups of reac-tions in reaction sets for easy organization and retrieval. PRO/II comes with two predefined reaction sets, which contain data for the important Shift and Methanation reactions.

The Reaction Definitions dialog box in Figure 36 shows the contents of the user-defined reaction set, FURNACE_RXNS. The currently defined reactions are named H2BURN and METHBURN. Most reaction properties are entered through this dialog box. The , , and buttons allow you to input heats of reaction, equilibrium data, and kinetic data.

Figure 36: Reaction Definitions

Dialog Box

H... E... K...


PRO/II provides six types of reactor units that use reaction data supplied through the Reaction Data dialog box. Each requires a different subset of the reaction data and you only need to enter the required data for the specific reactor. Table 17 indicates which reaction data are required, R, and which are optional, O, for the six reactor types.

Reaction Stoichiometry

You can enter reaction stoichiometry by clicking on the Definition linked text. A table will appear that allows you to define your reaction by sim-ply filling in the blanks. PRO/II will even check your stoichiometry for errors. In Figure 36, the stoichiometry has already been defined for both reactions.

You should be aware that PRO/II selects the default reaction rate expres-sions based on the stoichiometric coefficients. For example, if you input a reaction as:

2A + B = 2C

PRO/II will generate the following rate expression:

rate1 = K [A]2 [B]

If, however, you enter the same reaction using the stoichiometrically-equivalent form:

A + 0.5 B = C

PRO/II will generate the following rate expression:

rate2 = K [A] [B]1/2

Clearly, a given reaction can have only one rate expression. The expres-sion is determined by the physics of the problem and should be indepen-dent of the way the reaction is written. PRO/II uses power law kinetics with the stoichiometric coefficients as the exponents. It is thus important that you enter your stoichiometry to reflect the actual reaction mecha-nism. If, for example, you know that this reaction exhibits tri-molecular

Table 17: Reactor DataReactor Type Data Type

Stoichiometry H E K

Gibbs O

Conversion R O

Equilibrium R O R*

CSTR or Boiling Pot R O R*

PFR R O R*

Batch R O R*

* These data can be entered through the reactor unit dialog box.


kinetics, then you should enter it as 2A + B = 2C and PRO/II will select the correct rate expression. If you choose not to do this, you are always free to manually override the expression PRO/II has selected for you.

Heat of Reaction DataYou can specify heat of reaction data by clicking that appears to the right of each reaction. In addition to the heat of reaction, you can also input the phase and temperature at which the measurement was taken. If you do not provide values, PRO/II will calculate the heat of reaction from heats of formation contained in its libraries.

Reaction Equilibrium Data Clicking activates a dialog box that allows you to input reaction equilibrium data. The reaction equilibrium constant is:

(11)

where the ν's are the coefficients in the stoichiometric expression. By convention, the exponents are positive for products and negative for reactants. PRO/II expresses liquid activity in terms of mole fractions and vapor activity in terms of partial pressure. You can provide temperature dependent K-values by supplying coefficients (A,B,C,...) for the series:

ln(K) = A + B/T + Cln(T) +DT + ET2 + FT3 + GT4 + HT5 (12)

Reaction Kinetic DataClicking allows you to define the rate expression for the selected reaction. The rate expression has the form:

(13)

The temperature dependence is a corrected Arrhenius model, where:

■ A is the pre-exponential factor.

■ E is the activation energy.

■ n is the temperature correction exponent.

By selecting n=0, the standard Arrhenius form is recovered. Power law kinetics are used, and order is the reaction order for each component. Click to enter the reaction order. As you have just learned, if you do not provide component orders, PRO/II will use the stoichiometric coefficients from the reaction definition you provided.

H...

E...

K activityivi

i∏=

K...

Rate = Aexp[-E/RT]Tnactivityi

orderi

i∏

Reaction Order & Activity Phase...


Kinetic Procedure

Data

The Procedure Data function in PRO/II enables you to supply FOR-TRAN code for kinetic reaction rate calculations without the need for compilation and linking. Procedure blocks can be accessed in much the same way as FORTRAN programs call calculation subroutines.

The Procedure block has two main sections—declaration and code. The declaration section declares variable names, which are used in the code section but defined in the unit operation.

The code section contains FORTRAN-based statements which calculate the reaction rates. Specific unit operation data for the reactor or reactive distillation unit and reaction data can be accessed through number of predefined variables. Special intrinsic functions can be used in the code statements for direct retrieval of component properties

Accessing Reaction Data

After you enter your reaction data, you can select the appropriate reac-tion set from within each reactor unit dialog box. The two reactions, H2BURN and METHBURN, will be listed in the Extent of Reaction dialog box, where you can define the order in which the reactions occur and to what extent.

Figure 37: Conversion Reactor

Dialog Box


Using Specification and Define Features

The Specification and Define features of PRO/II allow you to control your simulation to meet your modeling requirements. Using Specifica-tion and Define you enter target values for flowsheet parameters. PRO/II meets these targets either directly or by adjusting the values of other parameters.

Specification Using Specification you set a target value of a calculated unit operating condition or stream property. PRO/II meets it by varying other parame-ters either within the unit operation or elsewhere in the flowsheet. You can express Specifications either as actual values or as functions of other parameters. For example, you can specify a product stream flowrate as 1000 and a flash drum temperature as its feed temperature plus 10°F.

DefineUsing Define you link the value of a variable to that of an upstream vari-able that has already been calculated. For example, you can Define a FLASH DRUM pressure as equal to the pressure of an upstream valve minus 0.1 bar.

Controller and Optimizer UnitsIf you want to make a specification on a unit or stream and achieve it by varying a parameter of another unit or stream, use a CONTROLLER.

If you want to meet more than one specification by varying the same number of parameters simultaneously, use a MULTIVARIABLE CONTROL-LER.

If you want to maximize or minimize a parameter by varying other parameters, use an OPTIMIZER.

Specification You can make specifications on parameters within a unit operation or parameters of product streams from the unit operation. The number of specifications you can make in a unit operation depends on the degrees of freedom that are available to the equations that solve the unit. For example, in a SPLITTER you can make N-1 specifications where N is the number of products. The Nth product is calculated from the equation matrix.

Table 18 shows a summary of the number of specifications allowed for the available unit operations.


Specification Example

In a FLASH DRUM you can make two specifications. The first specifica-tion can be pressure, pressure drop or temperature. The second specifica-tion can be either a unit specification or a stream specification.

➤ Select a unit specification from a drop-down list,

or, formulate a stream specification using linked text.

➤ Click on Parameter to display the Parameter dialog box where you select a product stream.

➤ Having selected a stream, click on Parameter to select a parameter from the list displayed in the Parameter Selection dialog box. The list and the options vary depending on the unit type.

Table 18: Number of Specifications AllowedUnit Number of Specifications Allowed

Flash 2 (only 1 stream specification)

Stream splitter P-1

Columns1, Sidecolumns1, Liquid-liquid extractors1 Unlimited

Shortcut column 2(P-1)

Controller1 1

Multivariable controller (MVC)1 Unlimited

Optimizer2 Unlimited

1 Number of Specifications = Number of Variables2 Number of Specifications = Number of Variables - Number of ConstraintsP = Number of Product Streams

78 Using Specification and Define Features

Absolute Specification Suppose you want to specify that the selected stream should contain 100 kg moles/hr of butane.

➤ In the Parameter Selection dialog box, select Flowrate then SelectedComponents, then NC4 as Starting Component.

➤ Return to the Flash Drum dialog box, click on value and enter 100. Your absolute stream specification has been set:

Relative SpecificationSuppose you want to formulate your specification as a function of another parameter in the flowsheet. Specify that 95% of the butane in the feed is recovered in the selected product stream.

➤ Click on = in the linked text on the Flash Drum dialog box and click on / parameter.

The linked text changes to

➤ Select the first parameter as described above.

➤ For the second parameter, select Total Unit Feed from the Constant/Stream/Unit list on the Parameter dialog box, then select the param-eter as before.

➤ Return to the Flash Drum dialog box, click on value and enter 0.95.

Your relative specification is now complete.

If you want to make more complex specifications involving more than two flowsheet parameters, use a CALCULATOR.

Note: Infeasible specifications are the leading cause of non-conver-gence of flowsheets. The specifications you provide must be realistic. For example, if a unit's feed streams contain 100 kg/sec of hexane, it would be infeasible to specify a product recovery rate of 120 kg/sec of hexane.


Define The Define feature allows you to dynamically link the value of a variable to that of an upstream variable that has already been calculated. When-ever the upstream variable changes, perhaps as a result of being in a recycle loop, the value of the Defined variable also changes according to the Definition you have made. You can define almost any input parame-ter. Some examples are shown in Table 19.

You know if a parameter is definable by the state of at the top of the dialog box. Click in the field you want to define. If is enabled, you can define the parameter.

Define Example

A COMPRESSOR is linked to an expander elsewhere in the flowsheet, so you want to define Work in terms of the work produced in that EXPANDER.

➤ In the Compressor dialog box, select Work from the drop-down list.

➤ Click in the data entry field, outlined in red.

➤ Click .

➤ In the Definition dialog box, check the Set up Definition for Com-pressor Work box.

➤ Click on Parameter to display the Parameter dialog box.

➤ Select Expander from the Constant/Stream/Unit list and select the correct expander from the Unit Name list.

Absolute and Relative DefinitionsLike a specification, a definition can be set as an absolute or a relative definition.

An absolute definition could be:

Whereas a relative definition may be:

Table 19: Examples of DefineDefine this parameter... ...in terms of this parameter...

column product rate estimate component flows in total column feed

compressor work expander work

flash drum temperature flash drum feed temperature

column top tray pressure expander outlet pressure

Define Define

Define

80 Using Specification and Define Features

Distillation Basics

In this chapter, we will take a closer look at the PRO/II column model. Stage efficiency, simple principles, specifications and variables, as well as non-linear equations and iterative methods, will be addressed.

Stage Efficiency

Theoretical, or ideal, stages have the wonderful property that their prod-uct streams are in equilibrium with each other. Of course in reality, ideal stages, like ideal-anything, are seldom encountered.

When a liquid and vapor are brought into contact, mass moves across the phase boundary until an equilibrium is reached and the net mass transfer of each component ceases. The time required to reach equilibrium is dependent on the rate of mass transfer, the contact time, and also how the phases are brought into contact. Consider the stages shown in Figure 38. For the reasons indicated in the figure, the small bubble contactor is closer to an equilibrium stage than the large-bubble contactor.

Figure 38: Effect of Bubble Size

on Stage Efficiency

PRO/II performs calculations in terms of theoretical stages, which means that you will have to translate actual trays into theoretical stages. You can use efficiency factors to describe how close a given stage is to theo-retical. Efficiencies depend both on the design and operating conditions of the tray. Under low flow conditions, for example, a bubble cap tray may be more efficient than a sieve tray, and a bubble cap tray near the top of a column may be more efficient than the same tray close to the bottom of the column.

PRO/II has three tray efficiency models: Murphree, vaporization, and equilibrium.

■ The Murphree model, illustrated in Figure 39, has a simple interpre-tation on McCabe-Thiele diagrams. Instead of stepping all the way to the equilibrium line, you only step part way. Unfortunately, Mur-phree values are not widely available.


Figure 39: Murphree Stage

Efficiency on a McCabe Thiele

Diagram

(14)

■ The vaporization model is the simplest of the three models, and con-sists of a multiplier, c, applied to the equilibrium K values for a com-ponent.

(15)

That is, the vaporization for that component is artificially adjusted versus the vaporization predicted by equilibrium. This model has the advantage that it can be extended to multicomponent distillation by defining different multipliers for different components or groups of components. PRO/II even allows you to provide a different set of multipliers on each tray.

■ The equilibrium model replaces K values with numbers that are closer to 1.0, resulting in less-than-theoretical splits.

(16)

Typically the equilibrium efficiency, Eeq, is between 0 and 1. In terms of x and y this equation is:

(17)

As with the vaporization model, you can enter different efficiencies for any component on any tray.

All of these tray efficiency models result in vapor leaving a tray that is not at its dew point. This violates the basic assumption of equilibrium used to derive the distillation column model. Therefore these tray effi-ciency models should be used sparingly. Apply them only to a few trays as needed to “tune” a model. Advanced users can use PRO/II's CON-TROLLER to automatically determine the efficiencies that allow the col-umn to meet survey values.

yA

xA

75% efficient:step 3/4 to

equilibrium curve

yA

xA

100% efficient:step to

equilibrium curve

Ei n,M

yi n, yi n 1+,–

yi n,* yi n 1+,–

------------------------------=

yi ciKixi=

Keffective K 1–( )Eeq 1+=

yi Ki 1–( )Eeq 1+[ ]xi=

82 Distillation Basics

The recommended method for determining tray efficiencies is the appli-cation of overall efficiencies. The overall efficiency is defined as the ratio of the number of theoretical stages to the number of actual stages required to carry out a given separation. Of course the number of actual trays must be greater than the number of theoretical trays. These factors are well known for many applications, and satisfactory models may be attained by using typical values.

A good practice is to divide the column into zones, and adjust the effi-ciencies within the zones until the desired fractionation is achieved at the measured temperatures and reflux quantities. The inherent advantage of this approach over the supplied tray efficiency models is that the vapors leaving the trays are always at their dew points. Table 20 gives some typ-ical values for overall tray efficiencies.

Treat all condensers and kettle reboilers as true equilibrium stages (100% efficient). Although subcooled condensers do not actually behave as equilibrium stages, you should count them as 100% efficient when you translate your column to a PRO/II model. PRO/II will make internal

Note: The above efficiency models have serious implications for the column top tray in particular, since the condenser duty is defined as the duty to condense the overhead vapor from its dew point to the desired condensing temperature. Using a tray efficiency on the condenser can result in a mixed phase leaving the condenser. For this reason, PRO/II does not allow you to apply efficiency factors to condensers. For similar reasons, you cannot apply efficiency factors to reboilers.

Table 20: Typical Overall Tray EfficienciesUnit Efficiency (%)

Simple Absorbers/Strippers 20-30

Reboiled Absorbers/Strippers 40-50

Deethanizers 60-65

Depropanizers 65-75

Debutanizers 80-90

Deisobutanizers (Refluxed) 85-95

SplittersC2, C2- 85-95

C3, C3- 95-100

C4's or C5's 90-100

Notes:1) Assume 65-75% for most columns with reboilers and condensers.2) At low reflux, split insensitive to number of trays in the model.3) Pumparounds usually modeled as 2 stages.


adjustments to ensure that subcooled condensers are simulated appropri-ately.

You can reasonably expect a tray efficiency in the range of 65 to 75 per-cent for any column with several distributed components and both reboiling and condensing systems. The overall tray efficiencies increase as the reflux ratio increases and the number of components in the system decreases.

Pumparound circuits produce a zone of nearly constant liquid composi-tion in a column. This reduces the fractionation in the zone and two stages are adequate to represent the zone. The bottom stage is the draw-off (usually also a product draw stage) and the top stage is the return stage.

Equations and

Unknowns

EquationsIt is relatively simple to write the equations that describe a distillation column. The same simple principles apply to all columns at steady state:

■ Mass and energy must be conserved.

■ The vapor and liquid leaving a theoretical stage must be in equilib-rium.

■ The liquid and vapor mole fractions must sum to 1.

Some people like to remember this using the mnemonic, MESH, which stands for: Mass, Equilibrium, Summation, enthalpy (H). Figure 40shows the model for an equilibrium stage.

Figure 40: General Equilibrium

StageLj , Vj

Fj

Qj

xj , yj

XF

hj , Hj

Tj , Pj

LDj

VDj

Liquid, vapor flowrate

Feed flowrate

Heater/cooler duty

Liquid, vapor mole frac

Feed mole fractions

Liquid, vapor enthalpies

Temperature, pressure

Liquid Draw rate

Vapor Draw rate

_

Subscript denotestray number

Tj Pj

Qj

LDj

VDj

Vj yj_

Lj-1 xj-1_

Lj xj_

Vj+1 yj+1_

Fj XF

_

Overbar denotes componentvectors: e.g., x = (x1, x2, ...xNC)

_

__


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■ Steady-state mass balances for each component on stage numyield NC equations:

(18)

■ The statement of equilibrium also yields NC equations per stageis usually expressed in terms of K-values. The superscripts here cate component i:

(19)

■ The summation equations contribute two equations per stage:

(20)

(21)

■ An enthalpy balance around the stage gives one more equatiostage:

(22)

The simple form of the enthalpy balance and equilibrium equations hthe fact that the K-values and the liquid and vapor enthalpies (h andare usually complicated, nonlinear functions of temperature, comption, and pressure.

Let NT and NC be the number of trays and components respectivelytotal number of equations for this simple column is:

Number of equations = NT (2NC + 3)

UnknownsIf you assume that the column pressure and all feeds are given, thetotal number of unknowns for a simple column with a reboiler and a bble-point condenser is:

Number of unknowns = NT (2NC + 3) + 2

Then, counting unknowns is easy:

■ Each of the NT-2 trays has a liquid and vapor composition (2NCtemperature, and net liquid and vapor flowrates (+3) for a total(NT-2) (2NC+3) variables.

■ The condenser (stage 1) has a liquid and vapor composition, a perature, a liquid return to the column (L1), a liquid side draw (theoverhead product), and a duty (Q1). The total is (2NC + 3)+1.

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yji

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xji

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∑ 1=

yji

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■ The reboiler (stage NT) has a liquid and vapor composition, a tperature, a vapor flow (VNT), a liquid side draw (the bottom product), and a duty (QNT). The total is (2NC + 3)+1.

Notice that there are two more unknowns than equations. Generaunique solution exists only when the number of equations and unknownsmatch. This distillation system needs two more equations (or two feunknowns) to be solvable. Providing this information is your job!

Specificationsand Variables

You can balance the number of equations and unknowns in two way

■ Eliminate two unknowns by providing their values

■ Add two equations by providing operating specifications.

In PRO/II, you can use both approaches. For example, when you pra value for a column duty, PRO/II assumes that it is the value you din your simulation. PRO/II eliminates that unknown by setting its vato the number you provided. PRO/II assumes that certain quantities, suchas overhead and bottom product rates, are estimates while others, sduties and side draw rates, are the values that you desire. In doingPRO/II always matches the number of equations and unknowns.

Specifications and variables are PRO/II's terminology for equations anunknowns. A direct consequence of the always-balanced design featureis that you must declare a new variable for every specification you wantthe column to meet. By declaring a quantity as a variable, you are tePRO/II that its value is unknown and that PRO/II should adjust (or varyit to meet the specification. The choices for specifications are almlimitless; variables, however, must come from the following categorie

■ Duties

■ Feed rates

■ Side draw rates.

In the two product column described above, you might specify valuethe overhead temperature and reflux ratio and declare the condensereboiler duties as variables. Any values that you provided for theduties will now be treated as initial estimates. These specification-vari-able pairs will cause PRO/II to adjust the values of the duties, as wethe column traffic, tray temperatures, and compositions to meet required overhead temperature and reflux ratio specifications. Younot have to declare tray temperatures, etc. as variables because PRO/IIalready considers them as such.


Table 21 lists the default status of all column attributes. PRO/II adjuststhe Calculated quantities from iteration to iteration until all equations aresatisfied; they are unknowns (variables) whose values you seek. If youprovide a value for a calculated quantity, PRO/II treats it as an initialestimate. Fixed quantities, in contrast, remain at their current values forall iterations. Think of them as variables whose values you provide. Ifyou want PRO/II to calculate the value of a quantity, that by default isfixed, declare it to be a variable and provide a specification. PRO/II nowtreats its current value as an initial estimate.

Overhead and Bottoms ProductsThe product streams designated as overhead and bottoms have a specialsignificance and are required input. As indicated in Table 21, thesestreams are normally calculated, so PRO/II considers the rates you enterto be estimates. In contrast, PRO/II considers the values you enter forside draw rates to be fixed. With multiphase condensers, the identity ofthe overhead stream is ambiguous, and you are always free to designatewhich of the condenser product streams is the overhead. If you do notexplicitly designate an overhead, PRO/II assumes the vapor stream is theoverhead. If there is no vapor, then the liquid stream is the overhead. ForCHEMDIST VLL E columns that produce two liquid phases (no vapor) atthe condenser, you must specify one of the phases as the overhead.

To impose specifications on a column, you enter them in the dialog boxshown in Figure 41. You can enter your list of variables in any orderbecause PRO/II does not associate individual variables with individual

Table 21: Default Status of Columns with No SpecificationsQuantity Status

Overhead and Bottoms Rates Calculated

Side Draw Rates Fixed

Duties Fixed

Feed Rates Fixed

Tray Temperatures Calculated

Tray Pressures Fixed

Vapor and Liquid Rates Calculated

Product Properties (e.g. Viscosity) Calculated

Tray Vapor or Liquid Properties Calculated

, Note: If you do not enter any specifications for a column, PRO/II willfix the duties at the values you provided via the and buttons. If you have not provided these val-ues, PRO/II wil l fix them at their default values, zero, and yourcolumn will almost certainly fail to converge.

Condenser... Reboiler...


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specifications. PRO/II adjusts all variables simultaneously to meespecifications.

Figure 41:Specification and

Variables

In general, specifications and variables are local to a particular unit,is, you usually adjust a column variable to meet a specification on same column. Using PRO/II's powerful CONTROLLER unit, you can mixspecifications and variables from widely separated units. This unit iscussed in the PRO/II Workbook, Flowsheet Control and Optimization.

NonlinearEquations

and IterativeMethods

In the previous section, you learned that, given proper specificatioPRO/II can solve the distillation column equations to determine the ues of the dependent variables. In practice, actually solving the colequations is an inherently difficult task because they are nonlinear. Sall of PRO/II's distillation column solving algorithms are iterative meods, a quick review of iterative methods is in order.

Iterative methods seek to solve equations of the general form:

f(x) = 0

The goal is to find a value of x (a root) that satisfies the above equaWe will call this value x*. All iterative methods start with an initialguess, x0, of the solution and generate a sequence of guesses: {x1,x2,...,xn,...} that hopefully approach x*.

Newton's MethodTo illustrate a typical iterative technique, consider how the Newtomethod solves the nonlinear equation, f(x) = 0. Figure 42 illustrates thebasic steps.


2.

lin-

ions.ttede them of

Figure 42:Newton's Method

1. Linearize the function about the current guess, xn. The linearizationabout the guesses x0 and x1 are the tangent lines shown in Figure 4

2. Solve for the root of the linearized equation and call it xn+1. Sincethe linearized equation approximates f(x), we hope that xn+1, theroot of the linearized equation, approximates the root of the nonear equation.

3. Test for convergence. For example:

If , then xn ¬ xn+1, go to step (1).

4. Done: , so xn+1 is accepted as a root of f(x).

Nonlinear PitfallsThere are few guarantees when it comes to solving nonlinear equatIf you asked an equation solver to find the roots of the functions ploin Figure 43, it would fail for cases (a) and (c). Case (a) fails becausfunction simply has no roots. Case (c) fails because of the continuuroots. Case (b) would solve; however the root it finds will depend onyour initial guess and might not be the one you desire.

Figure 43:Function Types: NoRoots (a), Multiple

Roots (b), and InfiniteRoots (c)

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Fortunately, mathematical models of physical processes will usuhave a steady-state solution if the process has a steady-state; this least you would expect from a model. In steady-state distillation, muple solutions are uncommon except in problems involving chemreaction or the formation of heterogeneous azeotropes.

The reason you should be concerned with these solvability issues isyou provide some of the equations (in the form of performance specations and choice of thermodynamic methods) that PRO/II must soIf your specifications cause the distillation equations to have no sotions, or infinitely many solutions, PRO/II will not be able to solve yourflowsheet. Such specifications usually constitute physically invalid opating conditions. For example, if you request an overhead product rate of200 lb/hr from a column whose total feed rate is only 100 lb/hr, the mbalance equations will have no solutions. Although the defect in thisticular example is obvious, there are many examples where seemvalid specifications result in a column that has no solutions.

Even when your equations are well posed and do have a solution, thno guarantee that the iterative method will be able to locate the soluThe success is somewhat dependent on the initial guess that you prFigure 44 illustrates some interesting behavior of Newton's method.

Figure 44:Initial Guesses forNewton's Method

■ Close to x*, the function looks very similar to the one in Figure 4and an initial guess that is sufficiently close to x* will lead to convgence.

■ If, however, your initial guess is close to a local extremum, the vaat the next iteration will be either very large or very small, dependon which side of the extremum your initial guess lies. An initguess at point A, for example, will yield a very large value of x the next guess. The algorithm will probably not be able to recoverfrom this.

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■ If you were lucky enough to guess point B, the next guess wouldvery close to the solution as indicated in Figure 44. Points A anillustrate a paradox in iterative methods. Although point A is cloto the correct solution (x*) than point B, an initial guess at pointwill not converge but an initial guess at point B will.

■ Certain guesses close to the local minimum will lead to boundeoscillations that will never settle down on a steady state. In Fig44, guess C leads to guess D, and guess D leads to guess C.CDCD... sequence will repeat forever

The set of initial guesses that can be iterated to the solution is callebasin of attraction for that solution. A large basin is desirable; it meathat the algorithm is forgiving of poor initial guesses. One of the grestrengths of PRO/II's I/O distillation and Enhanced I/O algorithms is they tend to have a large basin of attraction, and properly posed plems usually converge. The Chemdist and Sure algorithms, on the hand, tend to have smaller basins of attraction, therefore the qualithe initial guess can make the difference between convergence and diver-gence for these methods. The basin of attraction is also affected bshape of the function you are trying to solve. Figure 45 shows two func-tions, f(x) and g(x), that have the same root but very different basinattraction for Newton's method. As indicated in the graph, f(x) can converged from a larger range of initial guesses.

Figure 45:Basins of Attraction

for Newton's Method

By now you should be convinced that it is important to provide goodtial guesses for the column algorithms. To assist you in generating tinitial guesses, PRO/II provides several tools, called initial estimate erators, which will be discussed shortly.

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ChoosingFeasible

Specifications

It is very easy to make mistakes in providing specifications, in fact, mcolumn simulation errors are caused by improper specifications. Cumns with physically infeasible specifications will fail to converge. Ymust provide the simulator with meaningful specifications that uniqudefine the problem.

As you gain experience simulating distillation columns, you will findthat certain types of specifications are more likely to converge than ers. Consider the difference between imposing a purity and a recospecification on a column.

Generally speaking, purity specifications are more likely to be infeasthan recovery specifications. For example, thermodynamics dictatesyou will never be able to obtain 80 mole percent ethanol in a two stcolumn. This separation simply requires more than two stages, andsimulation will reflect this infeasibility by failing to converge. You havasked PRO/II to solve a system of equations that has no solution.

Recovery specifications, on the other hand, are almost always feaand hence are safer constraints to impose on columns. Your colucould recover 80% of the ethanol fed to it by simply maintaining a hoverhead flowrate.

A flowrate specification is an example of a potentially dangerous specation in hydrocarbon systems that contain hydrogen and other nondensable gases. Since only part of the overhead product can condensed, an overhead liquid flowrate specification can easily be insible.

Key ComponentsUnderstanding the concept of light and heavy keys will help you choappropriate specifications for your distillation problems. Distributedcomponents are the components that appear, in significant quantitieboth the bottom and overhead products. The light key is the lightesthe distributed components and the heavy key is the heaviest. Theand heavy keys appear in small nonzero quantities in the bottom overhead streams respectively. You can identify the key componendetermining the percent recovery of each component in the overheamaking a table such as the one in Table 22.


the

ou

Components should be listed in volatility order for this analysis. For theexample in Table 22, note that components A and B do not appear inbottom product and components H, I, and J do not appear in the over-head product. In other words, these components are non-distributed. Yshould be careful in formulating specifications based on non-distributedcomponents. Such specifications are usually meaningless because thetendency of the non-distributed components to exit from the top or bot-tom of the column is so strong that operating adjustments will not affecttheir split. It is almost impossible to operate a crude column to recover2% of the methane in the bottom product; methane is simply so volatileat the operating conditions of a crude column, that all of it will exit in theoverhead stream. This is an example of a specification that leads to a dis-tillation operation with no solutions, like the function in Figure 43(a).

At the opposite extreme, if you specify that 100% of the methane exits inthe overhead stream, your crude column would have an infinite numberof solutions, like the function in Figure 43(c). Although this specifica-tion is feasible, it is not a meaningful constraint on the column's opera-tion because 100% of the methane would have exited in the overheadwhether you asked for it or not. Although this specification may be met,it wil l not affect the operations of the crude column. It is vital that yourspecifications contain quantities that the column variables have somecontrol over. This is why it is safe to formulate distillation specificationsaround key component recovery.

Table 22: Separation KeysCOMP NBP %OVHD

Most Volatile A 50 100

B 65 100

Light Key C 79 98

Distributed Components

D 102 50

E 120 12

F 125 15

Heavy Key G 135 2

H 150 0

I 270 0

Least Volatile J 290 0

, Tip: For modeling purposes, non-distributed components can becombined to simplify the modeling effort. This will help tospeed up the simulation.


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The separation key table is also useful for determining the ideality oseparation. In Table 22, components E and F do not distribute as would expect from their normal boiling points. You would expect thproportionally more of component E would appear in the column ovhead product than component F. Therefore, there is some non-behavior with one or both of these components. Hydrocarbon systusually distribute according to their volatilities, making simplified anases possible. Unfortunately, systems with strong chemical interactare not as easy to analyze. For these systems, the presence of onecal could radically alter the behavior for another. In fact, this is the pciple used in extractive and azeotropic distillation.

InitialEstimate

Generation

You have already seen that the quality of the initial guess can makedifference between convergence and nonconvergence. For a distillcolumn, PRO/II requires initial estimates for all tray compositions, teperatures, flowrates, etc., which you are free to input manually, or cfrom a previous run. In most cases, however, you will probably findeasiest to use PRO/II's Initial Estimate Generator (IEG). The IEG syou the effort of inputting hundreds of guesses by automatically gening a complete set of initial guesses from a few key values that you vide. For particularly stubborn columns you can help the IEG to devea better starting profile by furnishing the reflux ratio and some key teperatures if they are available.

Figure 46 illustrates the role the IEG plays in the simulation. PROrequires you to provide a single value for column pressure; usuallyalso provide the condenser, top tray, and reboiler pressures, P1, P2, andPN respectively. In addition, you must supply values for all but one ofproduct stream flowrates. For a two product column, it suffices to pvide a guess for either the bottoms flowrate, LN, or the overhead flow-rate. The IEG then examines these values, along with the coluoperating specifications to generate initial estimates (denoted by thesuperscript) for all of the column variables, including duties. The sothen takes these initial guesses and iterates to the correct solutions

, Tip: Before you go to the trouble of providing extra informationsuch as temperature or composition profiles, try to run the coumn. If it converges, you have saved yourself some work. If itdoesn't converge, then start providing that additional information.


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Figure 46:Initial Estimate

Generator

PRO/II provides four different methods to generate initial guesses. your job to select the IEG model that is most appropriate for your prlem. The choices are: Simple, Conventional, Refinery, and Chemica

Simple The Simple model is PRO/II's default. It determines column profiles bsimple material balances and temperatures from estimates of the prcompositions. When you provide estimates on a few trays, PRO/II use linear interpolation to fill in the values on the remaining traysworks well with strippers and absorbers and is currently the only mothat will initialize liquid-liquid extractors.

Conventional The Conventional model works for the broadest category of probleand should be tried first for most applications. It uses classic Feshortcut distillation techniques to estimate product rates and comptions, which are then used to estimate temperature. Internal tray fare set up with material balances over each tray, using any specproduct rates and the column reflux estimate. For multi-draw columthe Conventional IEG uses a shortcut method developed by SIMSCI.User-supplied performance specifications and estimates are incorpowhenever possible. When performance specifications are unsuitableshortcut calculations, e.g., internal column flows or tray temperaturthe Conventional IEG must find other specifications. The first alternspecification is always the estimated rate for the column overhead otoms product. The quality of the column initial estimate is therefore pticularly sensitive to the overhead or bottom flowrate that you providso estimate this value carefully.

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PN L N x* y* T*

P V* L *

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ColumnSpec’s

, Note: You must also supply the rates for all side draws. As indicatein Table 21, these are handled differently from the overheaand bottom draws. PRO/II treats the furnished side draw ratesas fixed quantities rather than as estimates.


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Refinery The Refinery model was developed specifically for the multi-draw, sidestripped columns that are common in petroleum refineries. It also special functionality to accommodate pumparound circuits and you typically use this method for atmospheric and vacuum crude columFCC main fractionators, and coker columns. It applies the conventiomodel to the main and side columns repeatedly until the estimatesconsistent with each other. For less complex columns, the RefineryConventional models produce the same results.

Chemical The Chemical model is very time consuming and you should seleconly when the other models fail. It involves the calculation of a serieadiabatic flashes up and down the column trays several times (if nesary) to generate a good initial composition profile. Although it can used with any column solution algorithm, you will usually select thChemical IEG model only when you have highly non-ideal problems,which require you to use the Chemdist column solving algorithm. Thproblems are typically azeotropic, extractive, or reactive distillation.

SubsequentRuns

Keyword users can instruct PRO/II to initialize the column calculatiothrough either the IEG or user-supplied profiles. Once a solution to a distillation problem has been attained, subsequent runs will execute fasyou bypass the IEG procedure and supply the converged temperatuvapor flow profiles directly to the column. This is strictly optional andcan be accessed only through keyword input files. See the User SuppliedProfile Estimates section in the PRO/II Keyword Manual.

PROVISION users need to be aware of how subsequent runs are inized. Assume that you have successfully converged your column andwish to investigate the effect of slightly changing your specifications.You would expect the new solution to be close to the previous solutionWith this in mind, PRO/II initializes the next run using the most recencalculated product flowrates, rather than using the values you initestimated (recall that the IEG relies heavily on product rate estimaThis strategy works well in the vast majority of cases because the pously converged results are usually better product rate estimates thathe values you provide.

, Note: A serious problem can arise when you attempt to correct anrerun a failed column simulation. Often the final set of guessethat the solver generates before it fails are very bad; see initguess A in Figure 44 for example. In this case, subsequent ruwill be initialized with the bad product flowrates and the IEGwill produce initial estimates that are so far from the solutionthat they will never converge.


To remedy this problem, you can force PRO/II to use the initial rate esti-mates that you provided. Simply uncheck the Use Previous Solution forInitial Estimate box in the Column - Initial Estimates dialog box.

When a column appears in a recycle loop, the IEG is totally bypassedafter the first recycle iteration. Instead, PRO/II uses the previously calcu-lated solution as the initial guess at the current recycle iteration.

AlgorithmSelection

Choosing the column algorithm is a relatively simple, but important task.Table 23 summarizes some key features of the five column algorithms.

Your selection will be based on the following two factors:

■ The thermodynamic complexity of the chemical species

■ The mechanical complexity of the column.

Table 23: Distillation Column Algorithm FeaturesFeature I/O Sure Chemdist Liquid-

LiquidEnhanced I/O

Very Fast ✔ ✔

Forgiving of Poor Initial Estimates ✔ ✔

Side Strippers and Column Solved Simultaneously

✔ ✔

Built-in Thermosiphon Reboiler Models

✔ ✔

Built in Flash Zone Model ✔ ✔

Pumparounds ✔ ✔ ✔

Total Pumparounds ✔ ✔

Packed Column ✔ ✔ ✔ ✔

Tray Rating/Sizing ✔ ✔ ✔ ✔

Tray Efficiency ✔ ✔ 1 ✔

Water Decant on any Stage ✔ ✔

VLWE on any Stage ✔ ✔

Total Vapor and Liquid Side Draws ✔

Rigorous VLLE on any Stage ✔ ✔

Highly Non-Ideal Thermodynamics ✔

Reactive Distillation ✔ ✔

Two Liquids on any Stage ✔ ✔ ✔

(1) Only vaporization efficiencies available.


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Case 1 Thermodynamically simple but mechanically complex systems favorInside/Out or Enhanced I/O algorithms. These are PRO/II's fastest, mostrobust column algorithms and should be your first choice for most reery columns and for non-hydrocarbon systems that exhibit relativideal thermodynamics. Robustness is one of their strongest featureability to converge from poor initial estimates means that you do nhave to provide precise guesses for product flows and tray temperaVery rough guesses often suffice.

The Enhanced I/O algorithm is superior to the I/O algorithm for columwith total draws, or water decants off of column trays, since the alrithm is designed to converge even when zero flowrates on trayspresent. The only drawback to using the Enhanced I/O algorithm othe I/O algorithm is that the IEG does not work for all cases.

Case 2 Thermodynamically complex but mechanically simple systems are solved using the Chemdist algorithm. This algorithm is significanslower than I/O, but it rigorously handles three phase equilibrium can solve difficult problems such as reactive and azeotropic distillati

Case 3 The Sure algorithm falls somewhere between the I/O and Chemdist rithms. Although it is slow and rather sensitive to initial estimates, it handle columns which are mechanically more complex than Chemand thermodynamically more complex than I/O. It is a good choice refinery columns that have a liquid water phase on stages below thedenser.

Case 4 Multi-component liquid-liquid extraction columns are modeled as coumns made up of theoretical trays by use of the Liquid-Liquid methTwo insoluble liquid phases are contacted on the trays with the comnents to be extracted being selectively transferred from the heavy lphase to the light phase. The thermodynamic system selected for thuid-liquid extraction column must be a liquid activity method whichcapable of predicting liquid/liquid equilibrium.


Setting up a Case Study

The PRO/II Case Study is an executive level feature that allows you to perform parametric studies on a base case solution by altering data selec-tively and re-running. A Case Study allows you to make changes to input data and examine the effect of those changes on the values of calculated data or functions of calculated data.

A case study allows you to change the value of a specification but not the type of specification. A case study does not allow you to change the flowsheet by adding or replacing unit operations or streams.

Terminology To understand the case study function properly, you must be familiar with the terminology.

You can have only one Case Study in a PRO/II flowsheet.

A Case Study consists of a number of Cycles.

Each Cycle represents a flowsheet solution.

You select the input Parameters you want to change. For each cycle, you enter the changes you want to make to the parameters.

You select the output Results you want saved for later examination. A result can be the value of one flowsheet parameter or a function of two flowsheet parameters.

You can change as many parameters and save as many results as you need.

Entering Case Study

Data

You can enter case study data before you run the base case. When the program runs, the base case will be executed first and the case studies will be executed afterwards. Alternatively, you can run the base case first, then enter case study data and execute the case studies. You can open an already solved flowsheet, add case study data to it and then exe-cute the case studies.

Defining Parameters

You must specify which parameters are to be changed. For each parame-ter you must supply the:

■ Starting value—you can supply a fixed value or an offset relative to the base case value.


■ Start cycle—the cycle at which the starting value is used and after which the incremental changes are implemented. Cycles before the start cycle use the value in the base case.

■ Incremental change per cycle that is to be applied to the starting value.

■ End cycle—the cycle at which the changing is to end. Cycles after the end cycle use the value in the end cycle. If you define the end cycle to be the same as the start cycle, the parameter will adopt its starting value at that cycle and keep the value constant for subsequent cycles.

➤ Click the Case Study button on the toolbar. In the Case Study Param-eters and Results dialog box, check the Define Case Study box.

Figure 47: Case Study

Parameters and Results Dialog Box

➤ In the linked text for the first parameter in the grid, click on Parameter and select a parameter.

➤ The default for both start and end cycle is 1; change them as required.

➤ The starting value defaults to the value in the base case. To change it, click on base case value and enter one of:

● an actual value

● a value equal to the base case value plus or minus an offset

● a value equal to a percentage (or fraction) of the base case value

➤ The incremental change per cycle defaults to zero. Click on it and define the incremental change as an absolute value or a value relative to the base case value.

100 Setting up a Case Study

An example of a completed entry is shown below.

To change another parameter, add a row to the grid and repeat the pro-cess. All parameters are varied concurrently.

Defining Results

Each case study cycle represents a flowsheet solution. Because of disk space considerations, the full results of each cycle are not stored on the data base. So, before you execute the run, you must define those Results that you want to be retained for later examination.

You define a result as:

■ a calculated flowsheet parameter

■ a function of a calculated flowsheet parameter and another flowsheet parameter (calculated or input) or a constant.

In the linked text for the first Result in the grid, click on Parameter and select a parameter. Add a row to the Results grid and repeat the proce-dure for the second result you want to save. If you want to define a result as a function, click on = and select an operator.

Executing the Case

Study

Click the Run button to execute the simulation. By default, the Base Case and all case study cycles will be executed. You can restrict this using the Execution Options list option in Case Study Parameters and Results dialog box.

When the base case and the case studies have solved, all input parame-ters and output results are available for you to examine in tables and as plots by selecting Output/Case Study from the menu bar.

■ You can define any number of Tables. In each table you can choose to present any or all of the parameters and results.

■ You can define any number of Plots. You can choose one parameter or result or the cycle number to be the x-axis. All other data are plot-ted on the y-axis.


102 Working with Keyword Input Files

Working with Keyword Input Files

Keyword input files (.INP) are free format ASCII text files that define a PRO/II simulation using specific commands known as keywords. You can import, export, and run keyword files within the PROVISION. Key-word files play many important roles in PRO/II:

■ They provide an alternate interface with the PRO/II calculational module.

■ They allow you to maintain compatibility with simulations that were run with earlier versions of PRO/II.

■ If you need help with a simulation, you can send your keyword file to SIMSCI for technical support.

■ They provide a compact means of storing simulation input.

■ If you have several similar flowsheets to run, you can create the first simulation within the GUI and then modify its keyword file and run the rest using the Run Batch option and/or the Case Study option.

You can import existing keyword files into the GUI using the Import...option from the File menu. This produces a .PRZ file within PROVI-SION if all the features are supported.

To generate a keyword file from your existing simulation file, choose the Export... option from the File menu and select Simulation Data to Key-word File. Enter the path and file name and click . By default, key-word files have the extension .INP.

Keyword files are easy to read and understand and data are entered in the following order:

GENERAL DATA

COMPONENT DATA

THERMODYNAMIC DATA

STREAM DATA

REACTION DATA

PROCEDURE DATA

UNIT OPERATIONS DATA

CASE STUDY DATA

You can run keyword files directly using the Run Batch option from the File menu, which is discussed in the next chapter.

OK

Running the Simulation

You can run a PRO/II simulation in several ways:

■ Interactively—available when your PRO/II simulation contains only fully supported GUI features.

■ Run Batch mode—available when executing either keyword input files or simulation files batchwise and not through the PFD window.

■ Run-Only mode—available for executing imported keyword input files with features that are not supported in the GUI.

Interactive Run

Capabilities

To run your PRO/II simulation interactively, you have two options: the Run button on the toolbar and the buttons on the Run palette.

The easiest way to run your simulation interactively is to click the Run button on the toolbar. This button will be bordered in red until you have entered the required input data. If you don't need to add breakpoints or otherwise step through your simulation, this is the quickest method.

You can stop an ongoing simulation using the Stop button and restart it with the Run button, if desired.

The Run Palette

For more control over your interactive simulation, use the buttons on the Run palette. Through the Run palette you can perform any of the follow-ing tasks:

■ Check the consistency of your input data.

■ Set breakpoints and step through a simulation.

■ View the flowsheet convergence and simulation results.

To view the Run palette, choose View/Palettes from the menu bar and highlight Run. PRO/II disables the buttons on this palette until you have supplied all required input data (i.e., there are no red-bordered buttons, unit identifiers, or stream identifiers). Table 24 describes the Run palette buttons and their functions.


Unit Color Cues

As your simulation progresses, individual unit operations change color (unless you disable the Show Run Colors option from the View menu). Table 25 details the relationship between the unit status and its color.

Table 24: Run Palette ButtonsButton Function

Enables you to view global status messages for the current simulation.

Checks the input data for inconsistencies.

Executes the simulation, either from the beginning or from a breakpoint. Before execution, the input data is checked for inconsistencies.

Enables you to step through the execution of the simulation by stopping at each unit operation in the calculation sequence.

Stops the simulation during execution. PRO/II completes its current calculation before stopping.

Enables you to select the units you want to assign as breakpoints. When the simulation is executed, it stops at these breakpoints.

Enables you to start the execution from any specified unit. You select a unit by highlighting it and then clicking this button.

Enables you to view the calculation history and any error messages that arise.

Enables you to view detailed output results of a highlighted unit operation or stream in the flowsheet of a simulation.

Enables you to see which units are assigned as breakpoints, by displaying these unit icons in magenta. Clicking the button a second time causes the flowsheet to revert to normal display.

Status

Check Data

Run

Step

Stop

Set Breakpoints

Goto

Messages

View Results

Show Breakpoints

Table 25: Unit Color CodingColor Significance During Simulation Execution

Pale Green Unit operation has not been calculated.

Red Unit operation has failed to solve.

Green Unit operation is in the process of being calculated.

Blue Unit operation has been solved.

Magenta Unit operation is at a breakpoint.

Dark Blue Unit operation was solved in a previous run.

104 Running the Simulation

Using Breakpoints

You can place breakpoints before and/or after any unit operation or loop by clicking .

Figure 48: Breakpoints Dialog Box

To set breakpoints using the Breakpoints dialog box, select the desired breakpoint type(s) using the appropriate check box. Select one or more units from the list and close the dialog box. You will remain in Break-point mode and the pointer will have a B attached to it. When you run the simulation, it will stop executing when it reaches a breakpoint.

To set breakpoints using the PFD, click to display the units with breakpoints. With the Breakpoints dialog box open, activate the check box to place the breakpoint before the unit, the check box to place it afterwards, or both. Click on the unit for which you want to set a breakpoint. The unit will turn magenta.

Run Batch Mode

You can execute keyword input (.INP) files and/or existing flowsheet simulation (.PRZ) files in Run Batch mode from within PRO/II. Running files in batch mode generates the standard PRO/II output file for each simulation. While executing batch simulations, you can continue to use other Windows-based applications.

To run a batch simulation:

➤ Close any open simulation.

➤ Select File/Run Batch from the menu bar and load a previously saved list of files using or, select the files you want to simu-late using .

➤ Click twice to run simulation in batch mode.

You can terminate the currently executing simulation by clicking or the entire batch execution by

clicking .

Set Breakpoints

Show Breakpoints

Load List... Add Files...

OK

Terminate Currently Executing Problem Terminate Batch Run Execution


Run-Only Mode

Certain keyword features in PRO/II are unsupported in the GUI. If PRO/II detects any of these unsupported features (i.e., solids unit opera-tions), you are only allowed to import the keyword input file in Run-Only mode.

In Run-Only mode, you can:

■ Review and modify the appearance of the PFD. You can move unit operation icons and streams to improve the appearance of your PFD.

■ Add drawing elements, STREAM PROPERTY TABLEs, and OLE objects to the PFD.

■ Perform all Run functions.

■ Export the flowsheet diagram and STREAM PROPERTY TABLE infor-mation to other Windows applications.

■ Edit the keyword input file, reimport it, and rerun it without having to leave PRO/II.

■ Use the flash and BVLE hotkeys.

In Run-Only mode you cannot:

■ View simulation data within the data entry windows (this includes component and thermodynamic data).

■ Perform any input function such as changing the calculation sequence. All buttons and menu options that access input simulation data are disabled.

■ Add/delete units or streams, or disconnect/reconnect streams.

■ Export the PRO/II keyword input file.

106 Running the Simulation

Generating Output

PRO/II helps you generate accurate, professional reports. The standard output report format gives you comprehensive information on all unit operations and stream properties. Or, you can enhance your own reports by including plots, tables, and flowsheet diagrams from PRO/II. You have a wide variety of options at your fingertips for tailoring your simu-lation results to meet your specific needs including: customizing the out-put report format, exporting data to spreadsheet programs, creating plots and tables, and annotating your flowsheet.

Interactive Output

You can interactively view summary results for units and streams. For individual units, right-click on the unit and select View Results from the menu. For individual streams, right-click on the stream and select ViewResults from the menu.

You can change the default viewer used for displaying individual stream or unit output results by selecting Options/Viewer from the menu bar. Your options are Editor, (HTML) Viewer, and Default Browser (such as Netscape Navigator or Microsoft Internet Explorer).

You can present stream data on the Process Flow Diagram in the form of stream labels. A Stream Property Table is also very effective.

By default, the stream label shows the stream identifier. You can present more information on the stream label. Right-click on a stream and select Display from the menu. In the Stream Style dialog box, set desired style.

-200.0 -150.0 -100.0 -50.0 0 50.0 1000

400.0

800.0

1200.0

1600.0

2000.0

SaturatedVapor

Critical Point

SaturatedLiquid

15% Liq. SaturatedVapor

10% Liq. 5% Liq.

ProjectABC:Final

Results

Stream Property Table

Microsoft Excel

Plots

Output Report

1

7

2

3

4

5

6

C1

1

14

2

3

4

5

6

7

8

9

10

11

12

13

C2

1

22

2

3

4

5

67

8

9

10

11

12

13

14

15

16

17

18

19

20

21

C3

F100

2

3

4

5

6

7

PROJECT ABC

Flowsheet Diagram

14 CUT14 929.9999 929.9999 859.9471 70.0528

18 CUT18 280.0000 280.0000 279.9494 0.0506

MOLE FRAC H/C LIQUID 0.0000 0.0000 1.0000 0.0000

TOTAL RATE, LB-MOL/HR 8793.9990 8793.9990 3803.1150 4990.8843

PROJECT TRAINING PRO/II OUTPUTPROBLEM DEW PT CALCS STREAM MOLAR COMPONENT RATES========================================================================= STREAM ID 1V 2V 3L 3V NAME DEW_VAPOR DEWHC_VAPOR DEWWTR_HCLIQ DEWWTR_VAPOR PHASE WET VAPOR WET VAPOR WET LIQUID WET VAPOR

FLUID RATES, LB-MOL/HR 1 WATER 2999.9998 2999.9998 378.4306 2621.5688 2 CO2 35.0000 35.0000 2.4576 32.5424 3 N2 30.0000 30.0000 0.8023 29.1977 4 C1 889.9999 889.9999 46.8987 843.1011 5 C2 300.0000 300.0000 32.8930 267.1070 6 C3 520.0000 520.0000 93.9485 426.0515 7 IC4 105.0000 105.0000 26.5595 78.4405 8 NC4 283.0000 283.0000 80.1884 202.8116 9 IC5 100.0000 100.0000 38.0399 61.9601 10 NC5 133.0000 133.0000 54.0894 78.9106 11 CUT11 165.0000 165.0000 99.2135 65.7865 12 CUT12 303.0000 303.0000 202.6387 100.3614 13 CUT13 559.9999 559.9999 452.9087 107.0913

15 CUT15 300.0000 300.0000 295.4998 4.5002 16 CUT16 300.0000 300.0000 298.8902 1.1098 17 CUT17 300.0000 300.0000 299.7665 0.2335

19 CUT19 260.0000 260.0000 259.9930 6.9762E-03

TEMPERATURE, F 817.6355 817.6362 362.7227 362.7227 PRESSURE, PSIA 300.0000 300.0000 300.0000 300.0000 ENTHALPY, MM BTU/HR 498.0910 498.0914 99.0669 87.3452 MOLECULAR WEIGHT 94.3977 94.3977 177.0008 31.4532 MOLE FRAC VAPOR 1.0000 1.0000 0.0000 1.0000 MOLE FRAC TOTAL LIQUID 0.0000 0.0000 1.0000 0.0000

MOLE FRAC FREE WATER 0.0000 0.0000 0.0000 0.0000


Figure 49: Stream Style Dialog

Box

If you make the selections shown above, the label display appears as:

You can move the labels by clicking and dragging them above, on, or below the stream line.

Stream Property

Tables

PRO/II's STREAM PROPERTY TABLE feature displays and prints data for flowsheet streams.

To create a STREAM PROPERTY TABLE:

➤ Click the STREAM PROPERTY TABLE button on the PFD palette, or select Output/Stream Property Table from the menu bar. A green outline appears attached to the cursor.

➤ Anchor the table to the PFD by clicking the left mouse button at the desired location.

➤ Double-click on the table to open the Stream Property Table dialog box.

108 Generating Output

Figure 50: Stream Property Table Dialog Box

➤ Select a table type from the Property List to be Used list. Change the table's appearance using entries in the Table Appearance box. Select the streams you want displayed.

The simplest property table is the Short Property List which shows the stream attributes below.

Output Report

You can examine most of your simulation results through the output report (.OUT file).

Report Options

PRO/II contains a wide variety of report options for customizing your output format. To set these options, select Report Format from the Out-put menu. From the sub-menu select:

■ Units of Measure

■ Miscellaneous Data

■ Stream Properties

■ Unit Operations

Note: If you want to define your own table, refer to the Customizing the Flowsheet chapter that follows.


Units of MeasureOn the Default Units of Measure for Problem Output Report dialog box, you can choose the units to be used for your output report. By default, the output units of measure set is identical to the input set. If you choose to use a different set for the output, you can use either a library set or the input set as a basis and you can modify the units used for individual properties as desired.

You can also choose to print out two output reports, one in input mea-surements and a second in the units of your choice. A single output file will contain both reports.

Miscellaneous DataIn the Miscellaneous Report Options dialog box, you can choose, amongst other things, which portions of the input data you would like reported (such as, the binary interaction parameters of defined library components) and whether to include the flowsheet mass balance in your output report.

Stream PropertiesYou can choose the way in which your stream data are reported (i.e., in terms of moles, weight, liquid volume, or gas volume) by selecting Stream Properties from the Report Format menu. You can also select if you want TBP Distillation reports to be printed.

Unit OperationsYou can set print options for individual FLASH DRUMs, COLUMNs, and REACTORs by selecting Unit Operations from the Report Format menu. Highlight the unit of interest and click . The Print Options dialog box for the highlighted unit appears and you can choose which items you want included in your output report.

Alternatively, you can double-click on the individual unit operation on the PFD and click to get the Print Options dialog box.

Generating a Report

To generate an output report for your simulation, click the Generate Report button on the toolbar or select Output/Generate Report from the menu bar. The default editor appears displaying the contents of your out-put report. PRO/II appends the .OUT extension to your file name and saves the output file in the same directory that you saved your simulation files. The default directory is C:\SIMSCI\PROII\USER.

Once you have created your output report, you can view it at any time by selecting Output/View Report from the menu bar. Your default text editor displays the output report.

Print Options...

Print Options...


Plots You can generate and display a variety of graphical plots for your output data. PRO/II plots output results for:

■ COLUMN internal flowrates, temperature, and composition

■ COLUMN separation factor, used for the analysis of column feed point and tray performance

■ HEAT EXCHANGER zone analysis

■ PHASE ENVELOPE

■ HEATING/COOLING CURVE

■ Case Study results

■ Physical Properties

■ Feed stream assay curves

Plot Drivers PRO/II can display plots using the SIMSCI driver or the following third party packages, such as Microsoft Excel and GNUPLOT (Microsoft Windows version). With Microsoft Excel, you can change plot colors, axis titles and other attributes to create a presentation quality graph.

➤ To change your plot driver, choose Options/Plot Setup from the menu bar.

Generating a Plot

To generate a plot in PRO/II:

➤ Select Output/Generate Plot from the menu bar.

➤ Select a unit and an Available Plot, and click .

You can:

■ Copy your plot to the Clipboard.

■ Export the plot data to a file as either tab-delimited text or comma-delimited text.

■ Print your plot.

■ Save your plot for future reference.

■ Open previously saved plots.

Figure 51 shows the flowrate and temperature profiles for a demetha-nizer column, generated by PRO/II using the default SIMSCI plotter.

Plot...


Figure 51: Column Flowrate and

Temperature Profiles

Exporting Data

You can save the keyword input file, flowsheet diagram, and the Stream Property Table using the Export option on the File menu. Saving plots, properties, and case study results generated in PRO/II are also addressed below.

■ Keyword Input File—The default export option in Export dialog box, it generates the keyword input file (.INP) for the active simulation.

■ Flowsheet—After exporting the flowsheet diagram, you can import it into other Windows applications using the Clipboard.

■ Stream Property Table—The table can be saved as either tab-delimited text or comma-delimited text. Once you've saved your STREAM PROPERTY TABLE as a text file, you can import it into Microsoft Excel (or any other spreadsheet program) and then use its data pro-cessing capabilities to manipulate and process your data.

■ Plots or Plot Data—You can export data to Microsoft Excel by select-ing Tools/Spreadsheet from the menu bar. You can also export plots, column reports, stream properties, and component rates. You can copy Case Study tables and plots to the Clipboard by selecting Out-put/Case Study from the menu bar. To do so, open an existing table or plot and select File/Export from the graph window to save the data.


Customizing the Flowsheet

The Options Menu

PRO/II allows you to custom-build your process environment, define your own stream property and units of measure lists, or choose your favorite editor or viewer. It's all under the Options menu, described in this section.

Stream Property Lists

Select Stream Property Lists from the Options menu to create and main-tain property lists for STREAM PROPERTY TABLES. Within the Define Property List dialog box, you can create, modify, delete, and save prop-erty lists. You can also:

■ Reorder the property entries in a selected list.

■ Change the format of the displayed data values.

■ Change the overall appearance of the table by adding blank lines or text, altering the line, border, and/or cell character widths.

The data formats originate from the C programming language. Table 26shows more details. Since PRO/II stores new property lists unless you explicitly delete them, you can use the same property list in more than one simulation.

Your custom table will appear in the Property List to be Used list when you add and open a STREAM PROPERTY TABLE on the flowsheet.

Units of Measure Lists

The Units of Measure (UOM) library contains three default sets: English, Metric, and SI. You can create, copy, edit, rename, or delete UOM sets for the Units of Measure library. Clicking allows you to choose English, Metric, or SI as a basis and modify the set to fit your requirements. PRO/II stores user-defined UOM sets in the library.

You can specify any set as a global default or as a simulation default for either input data or output reports. The global default set remains in effect for future PRO/II sessions, whereas a simulation default only

Table 26: Data FormatsFormat Print Type

%d integer

%f floating point number

%.nf floating point number with n decimal places

%s character string

Create...


affects the current simulation and is selected by clicking the UOM tool-bar button.

Drawing Defaults

You can set three types of drawing defaults:

■ General

■ Unit Display

■ Stream Display.

General Drawing Defaults include zoom increments, pan increments, paper size, the unit icon palette, and other miscellaneous features, including a check box to prompt for unit and stream names as they are created. Figure 52 shows the General Drawing Defaults dialog box.

Figure 52: General Drawing

Defaults Dialog Box

Choosing Unit Display from the Drawing Defaults menu gives you the Unit Display dialog box. In this dialog box, you can select the type of unit operation you want to change and enter any changes for the label format and starting number. For certain operations, you have a choice of icon symbol. These changes affect any unit operation that you subse-quently place on the PFD. However, they will not change existing units. Figure 53 shows the Unit Display dialog box with the SIMPLE HEAT EXCHANGER icon selected. For this unit operation, you have a choice of five icons.

To change the style of an individual unit on the PFD, right-click on the unit to access the unit menu, and choose Display. A similar dialog box will appear.

114 Customizing the Flowsheet

Figure 53: Unit Display Dialog

Box

Choosing Stream Display from the Drawing Defaults menu brings up the Stream Style dialog box shown in Figure 54. This dialog box allows you to change various aspects of the stream style.

Alternatively, you can change the number or label of an individual stream in a Stream Data dialog box without altering the ongoing num-bering sequence.

Figure 54: Stream Style Dialog

Box


Simulation Defaults

You can set five types of Simulation Defaults:

■ Problem Description

■ Units of Measure

■ Thermodynamic System

■ Assay Characterization

■ Autosave

Select Problem Description to enter a user name, project identifier, site, site, date, and problem description that will be included each time you open a new simulation. This feature is useful for defining problem description items that don't change frequently.

As previously mentioned, the Units of Measure option allows you to set the default units of measure for data input and the default set for output. This feature allows you to match your company's measurement stan-dards. Note that English units are the startup default.

PRO/II does not have a default thermodynamic system. However, you can select a default method by selecting the Thermodynamic Systemoption.

Select Assay Characterization allows you to set defaults for characteriz-ing your assay data. Again, you can match standard company procedures with this feature. Clicking will reset PRO/II to its orig-inal internal defaults.

Select Autosave to specify how frequent you want PRO/II to save your current work. This option is not active by default.

Other Options The Options menu also contains a series of miscellaneous tasks. Select the appropriate option to carry out the associated function:

■ Colors—change the default PRO/II colors, such as icon fill color, the flowsheet color, and the border colors for the different data types, as well as the border style and line width.

■ Editor—change the editor (such as Brief, Edit, or Notepad) that is used to display and print keyword input files and output reports. The default editor is the Programmer’s File Editor (PFE).

Note: This can be a dangerous option to set, as choosing an inappro-priate thermodynamic system will cause erroneous results.

Restore Defaults


■ Viewer—change the default viewer used for displaying individual stream or unit output results; options are Editor, (HTML) Viewer, and Default Browser (such as Netscape Navigator or Microsoft Internet Explorer).

■ Font—change the font, font style (bold, italic, etc.), and font size used for the palettes and the dialog box displays.

■ Plot Setup—add a new plot driver or to change the default plot driver.

■ New File on Startup—use this toggle option (✓) to automatically cre-ate a new file upon startup of PRO/II.

■ Welcome to PROVISION Window—use this toggle option (✓) to bypass or restore the welcome message for future PRO/II sessions.

■ Suppress Run Warnings—use this toggle (✓) to suppress the appear-ance of the Status dialog box so that the run continues without inter-ruption.

■ Maximize on New File—use this toggle (✓) to maximize a new file when created.

Adding Objects to

the PFD

Drawing ObjectsPRO/II provides six objects that you can place on the flow diagram to customize the look and increase understanding of the flow diagram with-out interfering with simulation data. From the Draw menu, you can add the following objects: text, line, polygon, rectangle, ellipse, and page.

Select Ellipse, Line, Polygon, or Rectangle to add the desired shape to the diagram. Use the <Ctrl> key to draw orthogonally-connected lines, polygons, squares and circles. For lines and polygons, press <Space> to set each anchor point for drawing in a new direction.

Select Text to include notes on your drawing. Once you choose text mode, you remain in text mode as long as you continue to click on the Draw Text dialog box; choosing exits text mode.

Select Page to mark off a section of your flowsheet diagram. You can then use the Export option from the File menu to export only this selected portion of the flowsheet to the Clipboard. Select File/Print... to print the selected page.

OK Cancel


OLE ObjectsYou can place OLE objects into PRO/II allowing communication in transferring documents between two Windows applications. Any OLE object that has been properly registered within the Windows operating system can be inserted into the PRO/II simulation by selecting Edit/Insert Object from the menu bar.

Use the Create New and Create from File radio buttons to select the method in which the object is to be created. Selecting Display As Icontells PRO/II not to display the embedded document and show only the application icon.

To embed the application document within PRO/II, select Create Newand the object type from the list of Windows registered objects.

To create an object from an existing document file, such as a Microsoft Excel spreadsheet for example, select the Create from File radio button in the Insert Object dialog box. Enter the name of the document file or click to locate the file. Browse...


Index

A

Alcohol package 37

Algorithms 97

Assaycharacterization options 57, 116data entry 50distillation data 50generating curves 49

Assay processingcontrolling 58defining cuts 53interpolating distillation curves 53process light ends 54steps 52

Autosave 116

Average gravity, calculating 55

B

Basic steps for building a simulation 14

Batch mode, running files in 105

Binary interaction parameters 110

Bottoms stream 87

Breakpoints 105

Buttonsdialog box 10toolbar 9

BVLE hotkey 63

C

Calculation engine 1

Case studyparameters 99results 101running 101terminology 99

Characterization options, assay 57

Chemdist algorithm 98

Chemical IOG method 96

Color cueschange defaults 116during data entry 10

during execution 11Welcome dialog box 6

Columnplot 111stage efficiency 81types 65

Component propertiescategories 27correlation coefficient plots 29DATAPREP 31fixed 28polymer 31refinery inspection 31solid 31temperature-dependent 29UNIFAC structure data 31user-defined 31

Componentsdatabanks 23defining 15, 21fill from structure 25ionic 27library 21petroleum 23polymers 26property prediction 25selecting 21solid 26types 21user-defined 25

Components, key 92

Composition, streamcompositional 47entering 47petroleum assay 48polymer 62reference 58solids 61standard conditions 48

Control-menu box 8

Conventional IOG method 95

Conventions, workbook 4

Convergence, recycle 44

Copyingsimulation 6streams 63

Creating a new simulation 6

Cutpoint setadding a secondary 58modifying the primary 58

Cuts, defining 53

D

Data entry windows 10

Data export options 112

Databanks 23

DATAPREP 31

Decant option, water 39

Declaration, procedure 76

Defaultsdrawing 114flowsheet 17global units of measure 19simulation units of measure 18

Define 80

Deleting a simulation 6

Desktop 7

Display, stream 115

Display, unit 114

Distillation curves, interpolating 53

Documents 3

Draw menu 117

Drawing defaultsgeneral 114stream display 115unit display 114

E

Edit menu 13

Editor 116

Efficiency, stage 81

Electrolytescomponent models 27thermodynamic methods 37

Ellipse 117

English units of measure 20

Enhanced I/O algorithm 98

Enthalpy balance 85


Entrainment 73

Equations 84nonlinear 88

Equations of state (EOS) 36

Equilibrium model 82, 84

Equilibrium statement 85

Examplesassay stream 50case study 101column profile 111component property plots 29define 80label display 108specification 78stream property table 109stream thermal conditions 46thermo applications 40

Exporting data options 112

F

Feed streams 43

File menu 6

Fixed properties 28

Flash calculationdefining 70dew and bubble point models 72entrainment 73mixer 71overview 69PRO/II unit operation 69solution approach 69splitter 71valve 71water and hydrocarbon models 72

Flash hotkey 62

Flowsheetadding OLE objects to 118adding shapes to 117building 14copying streams 64defaults 17exporting 112panning over the 11

Flowsheet manipulation unit ops 67

Font 117

FORTRAN-based statements 76

G

Generalized correlations 36

Global units of measure 19

Glycol package 37

Graphical user interface (GUI) 2

Gravitycalculating the average 55data 24, 51

H

Heat exchangers 66

Heat of reaction data 75

Help 3

Help menu 3

Hydrocarbon-water mixtures 39

I

Ideal methods 36

Importing keyword input files 6, 102

Initial estimate generationchemical 96conventional 95overview 94refinery 96simple 95

Input files 102

Input menu 8

Input units of measureSee Units of measure

Inside/Out (I/O) algorithm 98

Interaction parameters, binary 110

Intrinsic functions 76

Ionic components 27

Iterative methods 88

K

Key components 92

Keyword input fileexporting 102, 112importing 6, 102running in batch mode 6

Kinetic data 75

Kinetic procedure data 76

L

Launching PRO/II 6

Library

component 21component databanks 23DATAPREP 32units of measure 19

Light endsanalysis 51process 54

Line 117

Linked text 5

Liquid activity (LACT) methods 36

Liquid-liquid algorithm 98

M

Main windowcomponents 8figure 7

Maximize on new file option 117

Menudraw 117edit 13file 6help 3input 8options 113output 101, 108summary of functions 8tools 62view 11window 12

Menu bar 8

Methods, iterative 88

Metric units of measure 20

Mixer 71

Molecular weights,calculating 56

Multiple feeds 67

Multiple thermodynamic methods 41

Multiple view capabilities 12

Murphree model 81

N

New file on startup option 117

Newton’s method 88

Nonlinear equations 88

Normal boiling pointcalculate 55data 24

Normalize option 47

Number of unknowns 85

120 Index

O

Objectsdrawing 117OLE 118

Online help 3

Opening a simulation 6

Options menudrawing defaults 114miscellaneous tasks 116simulation defaults 116stream property lists 113units of measure lists 113

Outputinteractive 107stream property table 108stream style 107tables 107units of measure 19view results 107

Output menu 101, 108

Output reportgenerating 110options 109print options 110

Overhead stream 87

P

Pages 117

PalettesPFD 11Run 11

Panning the flowsheet 11

Parameters, case study 99

Particle size distributionpolymers 26solid components 26

Performance specifications 86

Petroleum assay streamassay data entry 50assay processing 52defining 48distillation data 50generating assay curves 49gravity data 51lightends analysis 51

Petroleum componentsapplications 24defining 23gravity data 24

normal boiling point data 24set of 57

PFD palette 8, 11

Phase change unit operations 65

Phasesproduct 68stream 46

Plotdrivers 111exporting 112generating 111options 111setup 117

Polygon 117

Polymersdefining 26particle size distribution 26properties 31stream 62thermodynamic methods 37

Pressure change unit operations 65

Primary cutpoint set 58

Primary workspace 8

Print options 110

PRO/IIcomponents 8exiting 6importing keyword files 102launching 6main window 7overview of functionality 1

Problem description 116

ProblemsSee Exercises

Procedure data 76

PROCESS 1

Process streamSee Stream

Process unitSee Unit operations

Product phases 68

Product streams 43

Pseudocomponent 55

R

Reaction datadefining 73equilibrium data 75heat of reaction 75kinetic data 75

selecting in unit dialog boxes 76stoichiometry 74

Reactors 66, 74

Rectangle 117

Recycle streams 44

Reference stream 58

Refinery inspection properties 31

Refinery IOG method 96

Resultscase study 101viewing 15, 107

Rigorous VLLE calculations 40

Run batch mode 105

Run capabilitiescolor cues 104interactive 103run batch 105run-only mode 106suppress warnings 117using breakpoints 105using the Run palette 103

Run palette 8, 11

Run simulation 15, 103

Run-only mode 106

S

Scroll bars 8

Searching for a unit or stream 12

Secondary cutpoint set 58

Sequencing 44

Shapes 117

SI units of measure 20

Simple IOG method 95

SIMSCI add-ons 67

Simulationcopying 6creating a new 6default UOM 18deleting 6importing a keyword input file 6opening 6running 15, 103steps for building 14

Simulation defaultsassay characterization 116autosave 116problem description 116thermodynamic system 116units of measure 116


Solid componentsdefining 26particle size distribution 26properties 31property data 26

Solid-liquid equilibrium 40

Solids handling unit operations 66

Solids stream 61

Sour package 37

Specificationabsolute 79column 86establishing 77example 78relative 79

Splitter 71

Stage efficiencydefinition 81equilibrium model 82Murphree mode 81typical values 83vaporization model 82

Status bar 8

Status button 10

Steps for building a simulation 14

Stoichiometry, reaction 74

Streamdefault designations 17display 115external feed 43internal feed 43product 43recycle 44search for 12style 107supplying process data 15, 45types 43

Stream manipulation unit ops 65

Stream propertiescomposition 47flowrate 47lists 113normalize option 47phase 46requirements 45thermal condition 46

Stream property tablecreating 108exporting 112

Stream utilitiesBVLE hotkey 63copying streams 64

flash hotkey 62

Structure data 31

Summation equations 85

Suppress run warnings 117

Sure algorithm 98

T

Table 107

TBP curve 53

Technical support 3

Temperature dependent propertiescorrelation coefficients 29entry options 29

Text 117

Thermal condition of streams 46

Thermodynamic methodsapplication examples 40categories 35electrolytes 37equations of state 36generalized correlations 36global default 116ideal 36liquid activity 36polymers 37selecting 15, 34selecting the correct 34solid-liquid equilibrum 40special packages 37transport properties 38using multiple 41

Thermodynamic properties 34

Title bar 8

Toolbar 8, 9

Tools menu 62

Transport propertiescalculational methods 38rigorous VLLE calculations 40unit operation requirements 38variables 38water decant option 39

U

UNIFAC structures 25

Unit operationscategories 65columns 65common features of all 67defining reaction data 73

display 114entering process data 15, 65flowsheet manipulation 67heat exchangers 66multiple feeds 67phase change 65pressure change 65product phases 68reactors 66search for 12SIMSCI add-ons 67solids handling 66stream manipulation 65thermodynamic options 67user-added 67utilities 66

Units of measurechecking 18global defaults 19library 19lists 113output 19report options 110simulation defaults 18, 116single field 19standard sets 20

Unknowns 85

User-added unit 67

User-defined componentsdefining 25fill from structure option 25

User-defined properties 31

Utilities 66

V

Valve 71

Vaporization model 82

Variables 86

View menu 11

View results option 107

Viewer 117

Viewer options 107

VLLE calculations 40

W

Water decant option 39

Welcome to PROVISION 6, 117

Window menu 12

Workbook conventions 4

122 Index

Contents

Estimating Component Data . . . . . . . . . . . . . . . . . . . . . . . . 1

Chiller Plant

Part 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Part 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Part 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Part 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Part 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Part 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Gas Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

MEK/Toluene Preheat. . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Hydrocarbon-Water Phase Separation . . . . . . . . . . . . . . . 35

Naphtha Assay

Part 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Part 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Part 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Phase Envelope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Compressor Curves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Debutanizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Rigorous Heat Exchanger . . . . . . . . . . . . . . . . . . . . . . . . . 55

Two Stage Compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Propylene Chlorination Reactor . . . . . . . . . . . . . . . . . . . . 63

Appendix A - Keyword (.INP) Files - English UOM . . . . 69

Appendix B - Keyword (.INP) Files - Metric UOM. . . . . 81

Getting Started Workbook i

Estimating Component Data

TASK In this exercise, you will use PRO/II and DATAPREP to create a user-defined component and predict its properties. To demonstrate the accu-racy of the predictive methods, we will try to reproduce the properties of acetone:

Retrieve the physical properties of acetone from PRO/II. Compare them with those that result from estimating the component properties in the procedures outlined below.

Part A Define acetone as a user-defined library component with a different name. Given its molecular structure above, use the UNIFAC structure and the fill option to generate all the component properties of acetone. In the second run add NBP = 329.44 K and see how the component proper-ties change.

Part B Supply the Joback structure and use the modified Joback methods within DATAPREP to estimate all the component properties of acetone (under a different name) with and without the NBP data.

✔ SOLUTION - Part A

Use the following steps to enter ACETONE2 as a user-defined compo-nent.

Step 1 Create a User-Defined Component

➤ Click the Component Selection button to open the Component Selec-tion dialog box.

➤ Click .

➤ Name your component ACETONE2 and click .

Figure 1 shows the dialog box once you have entered the data.

O

H3C CH3C

User-defined...

Add ->



User-Defined Dialog Box

➤ Return to the flowsheet by clicking .

Step 2 Define the Component Properties

➤ Click the Component Properties button.

➤ Click , highlight ACETONE2 as the component to be filled and click . Click .

➤ Click and add the appropriate data.

ACETONE2 is comprised of two parts:

■ a Ketone, Group 1300

■ a Paraffin, Group 0900

Figure 2 shows the completed Define UNIFAC Structure dialog box.

Figure 2: Define UNIFAC

Structure Dialog Box

OK

Fill from Structure... Move -> OK


2 Estimating Component Data

Step 3 Build the Flowsheet

➤ Place a VALVE on the flowsheet and add two streams, one feed stream and one product stream.

Step 4 Select a Thermodynamic Method

➤ Click on the red-bordered Thermodynamic Data button on the tool-bar.

➤ Select the Most Commonly Used Category, and then select Soave-Redlich-Kwong as the Primary Method.

➤ Click to add your selection to the Defined Systems box.

Step 5 Enter Stream Data

➤ Double-click on the feed stream.

➤ Enter the thermal condition.

➤ Enter a flowrate and the composition, which should be 100 mol % ACETONE2.

Step 6 Run the Simulation and View the Results

➤ Run the simulation by clicking the Run button on the toolbar. Each unit should turn green and then blue in sequence indicating that it has solved.

➤ To view your results, click the Generate Report button.

Run the simulation again to see how adding in some known data affects the predicted properties. Rename the simulation so as not to overwrite the previous output file.

Step 7 Change the Normal Boiling Point

➤ Click the Component Properties button.

➤ Click and enter 329.44 K as the NBP.

➤ Run the simulation as before.

Table 1 compares some of the predicted properties.

Add ->

Fixed...


✔ SOLUTION - Part B

In this approach, you use DATAPREP to estimate the component prop-erties. With DATAPREP, you can choose either UNIFAC or Joback structures.

➤ Launch DATAPREP.

➤ Press <7> for Property Prediction and <1> for Automatic Property Generation.

➤ Type ACETONE3 and define it as a SCRATCH component so that it resides in memory and is not added into a database.

➤ Select the type of structure: <1> UNIFAC, <2> Joback.

➤ Move the cursor up and down and enter the number of occurrences of each function group next to the appropriate identification number.

● UNIFAC: one 900 group and one 1300 group

● Joback: two -CH3 groups and one >C=O (non-ring) group

➤ When finished, return to the main menu and use the File Utilities and Process Simulation options to write the data to a PRO/II keyword input format.

Again, you can enter specific data, such as the NBP, to increase the accuracy of the prediction. Table 2 compares the properties predicted with DATAPREP against published data.

Table 1: Comparison of Properties Predicted with PRO/II and Published DataProperty UNIFAC UNIFAC with NBP

DataPublished Data

Molecular Weight 58.080 58.080 58.081

Specific Gravity 0.7099 0.7001 0.79543

Normal Boiling Point (K) 321.91 329.44 329.44

Critical Temperature (K) 500.25 511.95 508.15

Critical Pressure (kPa) 4802.5 4802.5 4701.5

Acentric Factor 0.2825 0.28253 0.32869

Table 2: Comparison of Properties Predicted with DATAPREP and Published DataProperty UNIFAC UNIFAC with NBP

DataPublished Data

Molecular Weight 58.080 58.080 58.081

Specific Gravity 0.75338 0.70175 0.79543

Normal Boiling Point (K) 321.910 329.44 329.44

Critical Temperature (K) 500.248 511.95 508.15

Critical Pressure (kPa) 4802.500 4802.5 4701.5

Acentric Factor 0.282526 0.28253 0.32869

4 Estimating Component Data

Figure 3 shows the keyword input file lines generated by DATAPREP for the Joback prediction without NBP data.

Figure 3: Keyword File for the

Joback Prediction

$ PRO/II physical property insert for: $ Name: ACETONE3$ Formula: C3H6O$$COMPONENT DATA NONLIBRARY 2, ACETONE3$ $ Thermo methods available for use:$ Data are missing to determine phase$ PHASE NONE = 2$ STRUCTURE 2, MW 2, 0.5808004E+02 SPGR 2, 0.7533822E+00 VC(M3/KG,MOLE) 2, 0.2095000E+00 ZC 2, 0.2419194E+00 ACENTRIC 2, 0.2825258E+00 NBP(K) 2, 0.3219100E+03 TC(K) 2, 0.5002482E+03 PC(PA) 2, 0.4802500E+07 FORMATION(V,J/KG,MOLE) 2, -.2178300E+09, -.1545400E+09 NMP(K) 2, 0.1730000E+03 HFUS(J/KG,MOLE) 2, 0.5123140E+07 RACKETT 2, 0.2657684E+00 SOLP 2, 0.9211874E+01 MOLV(M3/KG,MOLE) 2, 0.7716949E-01 SVTB 2, 0.0000000E+00 SLTB 2, 0.0000000E+00 SLTM 2, 0.0000000E+00 HVTB 2, 0.0000000E+00 HLTB 2, 0.0000000E+00 HLTM 2, 0.0000000E+00


Chiller Plant - Part 1

TASK Through guided practice, you will build a simulation of the process shown below. This is part of a chiller plant typical in natural gas process-ing. In subsequent parts of this example, you will add other sections of the plant to this simulation. Use the Peng-Robinson thermodynamic method.

Figure 4: Schematic of Chiller

Plant - Part 1

The process and equipment data are given in Table 3 and 4.

CompressorC-1

HX-1Cooler

D-2KnockoutDrum

P-1Pump

D-1Scrubber

InletGas

2 4 5

6

7

3 17

Table 3: Feed Stream DataComponent Mole % Component Mole %

Nitrogen 1.0 i-Butane 1.25

Carbon dioxide 1.6 n-Butane 3.0

Methane 72.5 i-Pentane 0.55

Ethane 11.5 n-Pentane 1.10

Propane 6.75 C6PLUS (PETRO Component) 0.75

Total Flowrate 4 X 107 standard vap ft3/day 1.0X 106 normal vap m3/day

Temperature 120°F 50°C

Pressure 205 psig 1520 kPa

C6PLUS Properties NBP 210ºF 99°C

API Gravity 73 Specific Gravity 0.6919

6 Chiller Plant - Part 1

✔ SOLUTION

Step 1 Create a New Simulation

➤ Select New... from the File menu.

Note that several buttons on the toolbar, including the Run button have red borders. When you have satisfied PRO/II's input requirements all red borders will disappear.

Step 2 Build the Process Flow DiagramIf the PFD palette is not already visible, click the PFD Palette button on the toolbar to bring it up. Click on the appropriate unit icons on the PFD palette to draw the PFD. To select and position a unit, just click on its icon.

A pointer with a box and flash drum attached appears. Move this to the main window and click again when the unit is in position.

In this manner, select and position the units as shown in the diagram using these PFD buttons:

➤ Click on the red-bordered on the PFD palette.

Note that the pointer now has an S attached to it. All available exit ports appear on each unit once you select . Required exit ports are red and optional exit ports are green.

Table 4: Equipment Data and Operating ConditionsUnit Description Data

D-1 Scrubber Temperature Pressure

85°F 203 psig

30°C 1500 kPa

C-1 Compressor Outlet Pressure Adiabatic Efficiency

600 psig 72%

4250 kPa 72%

HX-1 Cooler Hotside: Process Stream Outlet Temperature Pressure Drop

Coldside: Utility Air Inlet Temperature Outlet Temperature

110°F 5 psi 80°F 100°F

45°C 35 kPa 27°C 38°C

D-2 Knockout drum Flash drum with no change of pressure and no duty

P-1 Pump Outlet Pressure Efficiency

550 psig 65%

3900 kPa 65%

Streams

Streams


➤ Draw the streams on the flowsheet to connect the units.

After your first click, only the available feed ports are shown in red or green.

➤ Double-click on each stream and unit and change its name to that shown on the diagram above. Do not change any other data in the dialog box.

➤ Click to exit the dialog box. Note that spaces are not allowed in unit or stream names.

The completed PFD should now look like Figure 5 below.

Figure 5: Chiller Plant PFD in

PRO/II

After you finish building the flowsheet, the labels of all the internal streams are black and the available ports of all the units are green. At this point, all the unit labels have red borders and the border of the feed stream label is also red because you must still add data. Note that the border of is black, indicating that you have entered all neces-sary data for this function. To exit the stream connection mode, right-click, or click on so that it turns gray, indicating that the mode is no longer active.

➤ Before continuing, save the simulation as CHILL1.PRZ.

Step 3 Modify the Input Units of Measure

➤ Click on the green-bordered Units of Measure (UOM) button on the toolbar to verify the units of measure used in this simulation.

Note: Although not critical in this example, it is good practice to con-nect the FLASH DRUM hydrocarbon liquid product to the side port and to reserve the bottom port for a decanted water or sec-ond liquid product.

OK

Streams

Streams


For this example you will use either modified SI units or modified English units. Click and select ENGLISH-SET1 or SI-SET1 from the drop-down list.

➤ Check each item that it matches the input data given in the tables above.

➤ Make any necessary changes and click .

Notice that the border of the UOM button is now blue indicating that you have modified the data.

Step 4 Define the Components

➤ Click on the red-bordered Component Selection button on the tool-bar.

➤ Click .

➤ Select the Hydrocarbon Lightends Component Family and select components from the list displayed. Select a single component or a group of components (using the shift or control keys) and then click

to add them to the component list below.

➤ Add the components in the order presented in Table 3.


➤ When finished click to return to the Component Selection dia-log box.

➤ Click to enter data for the petroleum component C6PLUS.

➤ Enter its name, NBP and gravity data, and click .

Note that and List of Selected Components box now have blue borders.

Initialize from Library....

OK

Select from Lists...

Add Components

OK

Petroleum...

OK

Petroleum...


➤ Click to exit the dialog box.

Step 5 Select the Thermodynamic Method

➤ Click on the red-bordered Thermodynamic Data button on the tool-bar.

➤ Select the Most Commonly Used Category, and then select Peng-Robinson as the Primary Method.

➤ Double-click on Peng-Robinson, or click to add your method selection to the Defined Systems box.

➤ To specify the transport property methods, click and then .

➤ Check the Compute Transport Properties box and select Petroleum Correlations from the Transport System drop-down list, as shown in Figure 7.

Figure 7: Transport Properties

➤ Click in each of the three dialog boxes to save the entered data.

Step 6 Define the External Feed Stream

➤ Double-click on the feed stream INLET_GAS. Make sure that the stream type is Composition Defined.

➤ Enter the stream's thermal condition:

● Select Temperature as the first specification and enter value.

● Select Pressure as the second specification and enter value.

➤ Click .

➤ Select Total Fluid Flowrate and enter value.

You will need to locally override the flowrate dimensional units. To do so, with the cursor in the fluid flowrate field, click at the top of

OK

Add ->

Modify... Transport Properties...

OK

Flowrate and Composition...

UOM


the dialog box and change the basis to vapor volume and the units to ft3

or m3 and day. Click to return to the dialog box.

➤ Enter the individual component mole percentages into the compo-nent grid. You can move down the list using the <Tab> key. After entering the composition data, check that the total equals 100.

➤ Click to exit each dialog box and return to the PFD.

You do not need to enter data for any streams other than the INLET_GAS(the external feed stream to the process) because PRO/II calculates the others for you, based on your process conditions.

Step 7 Enter Operating Conditions for Each Unit Operation

➤ Double-click on each unit in turn and enter the required data includ-ing the unit identifier.

➤ Enter data for flash drum D-1. The First Specification is Pressureand the Second Specification is Temperature.

➤ Enter data for flash drum D-2. The First Specification is PressureDrop and the Second Specification is Duty. The duty of an adiabatic flash is zero.

➤ Enter data for heat exchanger HX-1.

➤ Click to set the heat exchanger specification.

➤ Select Hot Product Temperature from the list and enter value.

Change Units

OK

Note: As you return to the PFD after each unit operation, its unit identifier has changed from red (data missing) to black (data satisfied).

Note: By default, the horizontal stream is the hot side and the vertical stream is the cold side. Here this means that the utility stream is the cold side. You could use this dialog box to change the stream allocations if the reverse were true.

Specification...


Figure 8: Heat Exchanger

Specifications

➤ Return to the Heat Exchanger dialog box by clicking .

➤ Click the cold side and enter the appropriate data.

Figure 9: Cold Side Utility

Stream

➤ Close the Heat Exchanger dialog boxes and return to the PFD.

➤ Enter pressure and efficiency data for Pump P-1 and Compressor C-1.

When you have entered all the data, there should not be any red on the flowsheet. All stream and unit labels should have black borders. If any of the unit or stream labels has a red border, click on it and check the data. Save the simulation before continuing.


➤ Run the simulation by clicking the Run button on the toolbar. Each unit should turn green and then blue in sequence indicating that it has solved.

➤ To view your results, highlight PUMP P-1 and click the View Results button.

OK

Utility Stream...


Step 9 Save and Close the SimulationYou will use this simulation as a basis for a later example.

➤ Select Save on the File menu and save as CHILL1.PRZ.

➤ Select Close on the File menu.

Figure 10: Pump P-1 Results English UOM

Pump 'P-1' Feeds 3 Products 17 User Input Calculated ---------- ---------- Temperature, F 88.15 Pressure, PSIG 550.00 550.00 Pressure Rise, PSI 347.00 Work, HP 2.44 Head, FT 1293.94 Efficiency 65.00 65.00

Metric UOM

Pump 'P-1' Feeds 3 Products 17 User Input Calculated ---------- ---------- Temperature, C 31.75 Pressure, KPA 3900.00 3900.00 Pressure Rise, KPA 2400.00 Work, KW 1.62 Head, M 395.50 Efficiency 65.00 65.00



TASK Continue to build the chiller plant. Since you already entered the units of measure, components, and feed stream data in Part 1 you won't need to add these data again. Figure 11 shows the process schematic for this part. The portion of the flowsheet that you entered in Part 1 is gray, and the new units and streams you will now add are black.

Figure 11: Schematic of Chiller Plant -

Part 2

The new equipment data and operating conditions are provided below.

✔ SOLUTION Use the previous example, CHILL1.PRZ as the basis for this example.

➤ Select File/Save As... from the menu bar and save the example as CHILL2.PRZ.

Step 1 Add to the Process Flow Diagram

➤ Using Figure 11 as a guide, add units HX-2, HX-3, D-3, and V-1 to the flowsheet.

➤ Connect the vapor product stream from D-2 to HX-2.

CompressorC-1

HX-1Cooler

D-2Knockout

Drum

P-1Pump

D-1Scrubber

InletGas

HX-2Gas/GasExchanger

HX-3Propane

Chiller

D-3Cold

Separator

V-1Valve

2 4 5

6

7

4 17

12

8 9

10

11 13

Table 5: Equipment DataUnit Description Data

HX-2 Gas to Gas Exchanger

Hotside ∆P Coldside ∆Pi Approach Temp (Hot In - Cold Out)

5 psi 5 psi 10°F

35 kPa 35 kPa 5°C

HX-3 Chiller Hotside Outlet Temp Hotside ∆P Coldside refrigerant saturated liquid propane at

-13°F 5 psi -22°F

-25°C 35 kPa -30°C

D-3 Cold Separator Adiabatic Separation

V-1 Valve Outlet Pressure 245 psig 1800 kPa


➤ Add the remaining streams to the flowsheet. Enter the unit and stream names. The PFD now looks like Figure 12.

Figure 12: Chiller Plant in PRO/II

Step 2 Enter Operating Conditions for Each New Unit Operation

➤ Enter data for the new units.

In the Heat Exchanger dialog box for HEAT EXCHANGER HX-3 (Chiller), click and choose Refrigerant as the Utility Type. Select Propane from the Component list and enter the saturation temper-ature.

At this point there should not be any red borders on the flowsheet. All stream and unit labels should have black borders. If any of the unit or stream labels has a red border, double-click on it and check the data.


➤ Run the simulation.

➤ Highlight the cold separator overhead stream 10, click the View Results button and look at the thermal recycle rate. As you can see, the stream is all vapor.

➤ Generate an output report by clicking the Generate Report button or by choosing Generate Report from the Output menu.

Look at the HEAT EXCHANGER summary for HX-3. Find the flowrate of the refrigerant. You will use this rate as an initial estimate in the Part 3 of this exercise.

Step 4 Save and Close the SimulationPlease save this simulation as CHILL2.PRZ and you will use this simula-tion in the Part 3 of this exercise.

Utility Stream...

Note: PRO/II's refrigerant utility, used in unit HX-3, considers only latent heat effects, so the refrigerant inlet and outlet conditions are a saturated liquid and a saturated vapor, respectively.


Figure 13: Heat Exchanger HX-3

ResultsEnglish UOM

OPERATING CONDITIONS DUTY, MM BTU/HR 6.534 LMTD, F 31.835 F FACTOR (FT) 1.000 MTD, F 31.835 U*A, BTU/HR-F 205245.904 HOT SIDE CONDITIONS INLET OUTLET ----------- ----------- FEED 8 MIXED PRODUCT 9 VAPOR, LB-MOL/HR 4102.011 3460.975 M LB/HR 88.249 66.131 CP, BTU/LB-F 0.580 0.631 LIQUID, LB-MOL/HR 250.147 891.183 M LB/HR 11.943 34.061 CP, BTU/LB-F 0.602 0.600 TOTAL, LB-MOL/HR 4352.158 4352.158 M LB/HR 100.192 100.192 CONDENSATION, LB-MOL/HR 641.035 TEMPERATURE, F 55.574 -13.000 PRESSURE, PSIG 590.000 585.000 COLD SIDE CONDITIONS INLET OUTLET ----------- ----------- REFRIGERANT, LB/HR 36843.185 36843.185 SATURATION PRESSURE, PSIG 9.620 SATURATION TEMPERATURE, F -22.000

Metric UOM

OPERATING CONDITIONS DUTY, M*KJ/HR 6.546 LMTD, C 17.864 F FACTOR (FT) 1.000 MTD, C 17.864 U*A, KW/K 101.787 HOT SIDE CONDITIONS INLET OUTLET ----------- ----------- FEED 8 MIXED PRODUCT 9 VAPOR, KG-MOL/HR 1737.399 1462.350 K*KG/HR 37.413 27.927 CP, KJ/KG-C 2.428 2.646 LIQUID, KG-MOL/HR 107.456 382.506 K*KG/HR 5.166 14.652 CP, KJ/KG-C 2.515 2.510 TOTAL, KG-MOL/HR 1844.856 1844.856 K*KG/HR 42.579 42.579 CONDENSATION, KG-MOL/HR 275.049 TEMPERATURE, C 13.748 -25.000 PRESSURE, KPA 4180.000 4145.000 COLD SIDE CONDITIONS INLET OUTLET ----------- ----------- REFRIGERANT, KG/HR 15868.730 15868.730 SATURATION PRESSURE, KPA 167.655 SATURATION TEMPERATURE, C -30.000

Note: The utility calculations for the heat exchanger are performed during output generation and cannot be viewed by clicking the View Results button.



TASK Continue to build the chiller plant. Suppose that the refrigerant for the chiller HX-3 consists of a mixture rather than pure propane. You want to determine the flowrate of that mixture required to maintain a process stream (hotside) outlet temperature of -15ºF (-26ºC). Instead of using the HEAT EXCHANGER refrigerant utility in PRO/II, which is designed for use with single components, you now must introduce a refrigerant stream, with the correct composition, and use a CONTROLLER to determine the refrigerant flowrate.

The diagram shows part of the process schematic. The portion of the flowsheet that you entered previously is gray, and the new units and streams you will now add are black.


Plant - Part 3

The equipment and refrigerant stream data are shown in Table 6.

✔ SOLUTION Use the previous example, CHILL2.PRZ, as the basis for this example and save the example as CHILL3.PRZ.

Step 1 Change the Flowsheet Configuration

➤ Add a controller unit to the flowsheet.

CompressorC-1

HX-1Cooler

D-2Knockout

Drum

P-1Pump

D-1Scrubber

InletGas


HX-3Propane

Chiller

D-3Cold

Separator

V-1Valve

2 4 5

6

7

3 17

12

9

10

11 13

51

50

CN1

8

Table 6: Refrigerant Stream DataComponent Mole%

Ethane 2.5

Propane 97

i-Butane 0.5

Pressure 11.5 psig 180 kPa

Condition Bubble Point


➤ Remove the utility stream on HEAT EXCHANGER HX-3 by double-clicking on the unit and deactivating the check box for the utility stream.

➤ Add inlet and outlet streams to the cold side of HX-3. Name the inlet stream 50 and the outlet stream 51.

Figure 15: Chiller Plant PFD in

PRO/II

Step 2 Enter Stream Data

➤ Enter the composition data and define the thermal conditions for stream 50.

Even though the flowrate of this stream is going to be calculated by the controller, you must enter a flowrate here. This not only satisfies the data requirements of the dialog box but also serves as an initial estimate.

➤ Use the propane refrigerant rate from the previous example as the initial flowrate for this stream.

Step 3 Enter Unit Data

➤ Change the specification for HEAT EXCHANGER HX-3 so that the new refrigerant stream exits at its dew point. Select the Cold Product Liquid Fraction specification and set the value to 0.00.

➤ Double-click on the CONTROLLER. The Feedback Controller dialog box appears.

You want to vary stream 50 flowrate so that the temperature of stream 9 is -15°F (-26°C).

In the Specification group:

➤ Click on Parameter.

➤ Choose the hotside outlet stream for HEAT EXCHANGER HX-3 (stream 9) as the stream to specify.

➤ Click on Parameter in the Parameter dialog box.

➤ Select Temperature and return to the Feedback Controller dialog box.


➤ Enter -15°F (-26°C) as the value of the hotside outlet temperature.

In the Variable group box:

➤ Click on Parameter.

➤ Choose stream 50 as the stream to vary. Click on Parameter and choose Flowrate as the variable.

When complete, the Feedback Controller dialog box looks like Figure 16.

Figure 16: Completed Feedback Controller Dialog Box

➤ Click to save the entries and return to the flowsheet.

➤ Save the simulation before continuing.



➤ Create a STREAM PROPERTY TABLE for stream 50 with the Stream Summary list selected.

A portion of this table is shown below. Compare the quantity of refriger-ant required to that obtained in the previous example. Why are the results different?


OK


Figure 17: Refrigerant Stream

Results

English UOM Metric UOM



TASK Continue to build the chiller plant. Add a COLUMN and a COMPRESSOR. Use MIXER units to combine the plant liquid streams into one product and the plant vapor streams into another product.


Plant - Part 4

✔ SOLUTION Use the previous example, CHILL3.PRZ, as the basis for this example and save the example as CHILL4.PRZ.

Step 1 Add to the Process Flow Diagram

➤ Place a COMPRESSOR, two MIXERs and a COLUMN on the PFD. Con-nect the streams as shown in Figure 18. Name the units and streams.

CompressorC-1

HX-1Cooler

D-2Knockout

Drum

D-1Scrubber

InletGas


HX-3Propane

Chiller

D-3ColdSeparator

V-1Valve

P-1Pump

PipelineGas

C-2Compressor

T-1Stabilizer

M-2Mixer

M-1Mixer

Natural GasLiquids (NGL)

1

2

3

4 5

6

7

8 9

10

11

12

13

14

15

16

17

18

19

Table 7: Equipment DataStabilizer Column T-1

Actual Number of Trays 22

Overall Tray Efficiency 55%

Feed Location Tray 1

Top Tray Pressure 200 psig 1480 kPa

Column ∆P 2.5 psi 17 kPa

Bottom Product TVP 235 psig 1720 kPa

Compressor C-2

Outlet Pressure 600 psig 4240 kPa

Adiabatic Efficiency 73%


When you place the column, you will be asked to give the number of theoretical trays and to state whether the column has a condenser and a reboiler. Note that the Table 7 gives actual trays and tray efficiency. From this you must calculate the number of theoretical trays in the body of the column (22*55% = 12 stages). The kettle reboiler is simulated as a theoretical stage and thus is stage 13. This column has no condenser.

When complete, the PFD should look similar to Figure 19.

Figure 19: Complete Chiller Plant

in PRO/II

Step 2 Enter the Unit DataThe mixers require no data. Enter the COMPRESSOR data from the table.

➤ Double-click on the COLUMN. Check that the Number of Trays is correct and that the default selections for Algorithm and Calculated Phases are appropriate to your simulation.

➤ Click and enter the Top Tray Pressure and the Pressure Drop for the entire Column.

➤ Click to set the feed tray number. Check that the default entry for the Phase of each Product is correct.

Estimate the rate of the overhead product. You can make a good guess from the results of the previous run. You could also use the Define pro-cedure, assuming that the overhead stream consists of all the Nitrogen through Methane from the column feed (Figure 20).

Figure 20: Overhead Flowrate

Definition

Pressure Profile...

Feeds and Products...


➤ Click to check that Kettle (Conventional) has been selected.

➤ Click to select the Conventional initial estimate method.

➤ Click to enter the true vapor pressure specification. Check the Add Specifications and Variables box. In the Specifications grid, click on Parameter, choose the bottoms stream, 15, and select Vapor Pressure and True from the lists. Return to the Specifications and Variables dialog box and enter a value of 235 psig (1720 kPa).

➤ In the Variables grid, click on Parameter, choose Column and select Heat Duty of the Reboiler from the lists. The completed dialog box is shown in Figure 21.

Figure 21: Bottoms True Vapor

Pressure Specification

➤ Click to return to the PFD.



➤ Highlight the COLUMN and click the View Results button. Find the reboiler duty required to meet the liquid product specification.

➤ Select Output/Generate Plot... from the menu bar to plot an over-view of the temperature and flowrates, as shown in Figure 22 below.


Reboiler...

Initial Estimates...

Performance Specifications...

OK


Figure 22: Column

T-1 Profiles



TASK Suppose that a nearby refinery has been shut down and some columns are available at bargain prices. Your company is exploring a joint ven-ture with the Royal Gas Company to build a fractionation plant as shown in Figure 23 to process the liquids from your chiller plant and their plant.

Figure 23: Light Ends

Fractionation Plant

You have been asked to provide a quick design for such a plant. To save time, you want to perform a shortcut analysis. SHORTCUT COLUMNs are unsupported in PROVISION. However, using keyword input files you can run the problem in either Run Batch or Run-Only mode. Use the keyword input file, CHILL5.INP, found in the TRAINING directory, to determine the number of theoretical trays, feed locations, and approxi-mate reflux ratios for the three distillation columns.

✔ SOLUTION

Step 1 Import the Keyword Input File

➤ Select Import... from the File menu. Import the keyword input file CHILL5.INP from the TRAINING directory.

A message will appear indicating that unsupported features were found in your keyword file. You can examine a list of these features by click-ing .

➤ Close the Flowsheet Status dialog box to continue.

T-2SDeethanizer

T-3SDepropanizer

T-4SDebutanizerV-2

60Royal

Liquids

19 20

22

23

21

24

25

26

V-3 V-4

C2

C327

28Gasoline

C4’s

Yes


Step 2 Run the Simulation and View the Results You will have been automatically placed into Run-Only mode. Run the simulation and create an output file.

Read the results from the output (Figure 24). For example, for the deeth-anizer column, the recommended number of theoretical trays is 24, which is twice the calculated Fenske minimum trays. For a 24 tray col-umn, the feed should be introduced at tray 13.

Figure 24: Shortcut Column

Summaries

UNIT 2, 'T-2S', 'DEETHANIZER'

SUMMARY OF UNDERWOOD CALCULATIONS

MINIMUM REFLUX RATIO 2.08175 FEED CONDITION Q 1.40594 FENSKE MINIMUM TRAYS 12.14568 THEORETICAL TRAYS 2.00 * M-MINIMUM

TOTAL FEED R/R-MIN M/M-MIN REFLUX DUTY, MM BTU/HR TRAYS TRAY RATIO CONDENSER REBOILER ----- ---- ------- ------- ------ ---------- ---------- 18 9 1.975 1.500 4.111 -4.024E+00 1.022E+01 21 11 1.467 1.750 3.053 -2.989E+00 9.182E+00 24 13 1.284 2.000 2.673 -2.616E+00 8.810E+00 27 14 1.163 2.250 2.420 -2.369E+00 8.563E+00 30 16 1.077 2.500 2.243 -2.196E+00 8.389E+00

UNIT 4, 'T-3S', 'DEPROPANIZER'




UNIT 6, 'T-4S', 'DEBUTANIZER'






TASK Use the shortcut results from Part 5 to set up a rigorous simulation of the light ends fractionation plant shown in Figure 25. Begin with the flow-sheet built in Part 4, or create a new flowsheet and provide the feed data given below. Size each column for valve trays through the Tray Hydrau-lics dialog box. Use the I/O distillation algorithm for the calculations and choose Conventional as the initial estimate method. Vary the column duties to meet the specifications given in Table 10.

Figure 25: Light Ends

Fractionation Plant

T-2SDeethanizer

T-3SDepropanizer

T-4SDebutanizerV-2

60Royal

Liquids

19 20

22

23

21

24

25

26

V-3 V-4

C2

C327

28Gasoline

C4’s

Table 8: Feed Stream DataComponent Royal Gas Liquids

Stream 60 (kg-mol/hr)Royal Gas Liquids Stream 60 (lb-mol/hr)

Nitrogen 0.0454 0.1

Carbon dioxide 0.8165 1.8

Methane 1.8144 4.0

Ethane 56.699 125.0

Propane 99.7902 220.0

i-Butane 35.3802 78.0

n-Butane 68.0388 150.0

i-Pentane 4.5359 10.0

n-Pentane 21.7724 48.0

C6PLUS (petro. comp.)NBP = Density =

13.607898.9 °C0.6919 sp gravity

30.0210 °F73 API

Temperature 37.8 °C 100 °F

Pressure 4238 KPa 550 psig


✔ SOLUTION Use the previous example, CHILL4.PRZ, as the basis for this example and save the example as CHILL6.PRZ. Build the flowsheet continually and run the simulation.

Compare the duties and overhead product rates determined in this exer-cise with those from the shortcut calculation done in Part 5. The over-head rate estimates from the shortcut calculation were quite good, but the duty estimates were more approximate.

Table 9: Column Data T-2 T-3 T-4

Condenser Data

Type Partial Subcooled Subcooled

Pressure (psig) 410 240 100

Temperature (°F) --- 110 110

Pressure Data

Top Tray Pressure (psig) 415 245 105

Column ∆P (psi) 5 5 5

Estimates from Shortcut Results

Theoretical Stages 24 23 26

Feed Location 13 11 14

Reflux ratio 2.673 2.940 1.653

Overhead product rate (lb-mol/hr) 271.7 414.1 390.7

Table 10: Column SpecificationsDeethanizer T-2:

C3 in overhead product 2 mol %

C2/C3 mole ratio in bottom product 0.025

Depropanizer T-3:

C4s in overhead product 2 mol %

C3 in bottom product 2 mol %

Debutanizer T-4:

IC5 in overhead product 0.25 vol %

NC4 in bottom product 1 vol %

Table 11: Valve Operating ConditionsUnit Outlet Pressure (psig)

Valve V-2 425

Valve V-3 260

Valve V-4 130


Plot the liquid and vapor fractions of ethane and propane in column T-2 on a single plot. For column T-3, plot the separation factor of the light and heavy components. For column T-4, plot the overview of the tem-perature and flowrates.

Figure 26: Mole Fractions of

Ethane and Propane in Column T-2

Figure 27: Separation Factor in

Column T-3


Figure 28: Overall Temperature

and Flowrate Profiles in Column T-4


Gas Cooling

TASK Solve the flowsheet, shown in Figure 29, for all process conditions and flowrates. Solve it first with a recycle loop and then break the loop using a reference stream (Figure 30). Compare the calculation histories in both runs. Determine the number of iterations it takes to run with the recycle in place and how many it takes to run with the broken recycle.

Figure 29: Gas Cooling

Flowsheet with Recycle

Figure 30: Gas Cooling

Flowsheet with Broken Recycle

Table 12: Feed Stream DataComponent Mole Percent

Carbon Dioxide 1.39

Methane 85.92

Ethane 7.73

Propane 2.45

i-Butane 0.36

n-Butane 0.56

i-Pentane 0.21

n-Pentane 0.26

n-Hexane 1.12

Pressure 3600 psia 24820 kPa


Flowrate 1000 lb-mol/hr 455 kg-mol/hr


✔ SOLUTION The original flowsheet requires three iterations to converge and the bro-ken-recycle version converges without iterating. Figure 31 contains a portion of the output for the broken-recycle flowsheet.

Heat Exchangers: ∆P for all streamsT2 - T8 E2 outlet temp

5 psi15°F-20°F

35 kPa 8°C-29°C

Valves: ∆P across V1∆P across V2

1600 psi900 psi

11030 kPa6205 kPa

Flash Drum: Adiabatic

Reference Stream: TemperaturePressure

-20°F1090 psi

-29°C7515 kPa

Figure 31: Stream Molar

Component RatesEnglish UOM

STREAM ID 5 5X 6 7 NAME PHASE MIXED MIXED VAPOR LIQUID FLUID RATES, LB-MOL/HR 1 CO2 13.9000 13.9000 12.3398 1.5602 2 METHANE 859.2000 859.2000 812.3919 46.8081 3 ETHANE 77.3000 77.3000 63.1335 14.1665 4 PROPANE 24.5000 24.5000 15.8709 8.6291 5 IBUTANE 3.6000 3.6000 1.7665 1.8335 6 BUTANE 5.6000 5.6000 2.3734 3.2266 7 IPENTANE 2.1000 2.1000 0.5862 1.5138 8 PENTANE 2.6000 2.6000 0.6487 1.9513 9 HEXANE 11.2000 11.2000 1.3286 9.8714 TOTAL RATE, LB-MOL/HR 1000.0000 1000.0000 910.4396 89.5604 TEMPERATURE, F -20.0000 -20.0000 -20.0000 -20.0000 PRESSURE, PSIA 1090.0000 1090.0000 1090.0000 1090.0000 ENTHALPY, MM BTU/HR -0.0177 -0.0177 0.0913 -0.1090 MOLECULAR WEIGHT 19.6397 19.6397 18.2536 33.7306 MOLE FRAC VAPOR 0.9104 0.9104 1.0000 0.0000 MOLE FRAC LIQUID 0.0896 0.0896 0.0000 1.0000

Metric UOM

STREAM ID 5 5X 6 7 NAME PHASE MIXED MIXED VAPOR LIQUID FLUID RATES, KG-MOL/HR 1 CO2 6.3245 6.3245 5.6107 0.7138 2 METHANE 390.9360 390.9360 369.5078 21.4282 3 ETHANE 35.1715 35.1715 28.6959 6.4756 4 PROPANE 11.1475 11.1475 7.2080 3.9395 5 IBUTANE 1.6380 1.6380 0.8018 0.8362 6 BUTANE 2.5480 2.5480 1.0770 1.4710 7 IPENTANE 0.9555 0.9555 0.2659 0.6896 8 PENTANE 1.1830 1.1830 0.2942 0.8888 9 HEXANE 5.0960 5.0960 0.6025 4.4935 TOTAL RATE, KG-MOL/HR 455.0000 455.0000 414.0639 40.9362 TEMPERATURE, C -29.0000 -29.0000 -29.0000 -29.0000 PRESSURE, KPA 515.0000 7515.0000 7515.0000 7515.0000 ENTHALPY, M*KCAL/HR -5.5392E-03 5.5392E-03 0.0222 -0.0278 MOLECULAR WEIGHT 19.6397 19.6397 18.2513 33.6831 MOLE FRAC VAPOR 0.9100 0.9100 1.0000 0.0000 MOLE FRAC LIQUID 0.0900 0.0900 0.0000 1.0000

32 Gas Cooling

MEK/Toluene Preheat

TASK The process shown in Figure 32 preheats a stream that is fed to a distilla-tion column. The flash drum vaporizes 40 mole percent of the feed, and the heat exchanger further heats the flash drum liquid. Both the flash drum and heat exchanger have 1 psi (6.9 kPa) pressure drops. A total of 1.0 MM Btu/hr (1.05 MM kJ/hr) is available to the process.

Find the liquid fraction and temperature of the PROD stream and the two duties.

Table 13 shows the feed composition and condition. Use the NRTL ther-modynamic system, but replace its default vapor enthalpy and vapor density methods with SRKM.

Figure 32: Preheat Process

FDFeed

Prod

Vapor

HX

Table 13: Feed StreamComponent Mole %

Toluene 80

Methyl-Ethyl Ketone (MEK) 19

Water 1

Flowrate 100 lb-mol/hr 45 kg-mol/hr



Hint: Use one stream Specification and one Define.


✔ SOLUTION To vaporize 40% of the flash drum feed, use the following stream speci-fication:

The duty available to the heat exchanger is 1 MM Btu/hr (1.05 MM kJ/hr) minus however much duty the flash drum requires to vaporize 40% of its feed. Since the flash duty is unknown before the run, you cannot assign a value to the heat exchanger's duty. Instead, you should have PRO/II calculate the FLASH duty, and use the define feature to pass the calculated flash duty to the heat exchanger. The Define statement for the HEAT EXCHANGER will has the form:

Table 14 summarizes the results.

Table 14: Results of MEK/Toluene PreheatEnglish Units Metric Units

Flash Duty 0.7353 MM Btu/hr 0.7680 M kJ/hr

Heat Exchanger Duty 0.2650 MM Btu/hr 0.2970 M kJ/hr

PROD Temperature 233.96°F 112.35°C

PROD Liquid Fraction 0.6844 0.6619

34 MEK/Toluene Preheat

Hydrocarbon-Water Phase Separation

TASK This exercise illustrates the differences between a rigorous VLLE flash and a VLE flash with the water decant option. Simulate a three phase separator as an isothermal flash at 300°F and 300 psia for the crude stream given in the tables below. Use VLLE SRK Kabadi-Danner (SRKKD) thermodynamics and VLE SRK thermodynamics with the water decant option, along with the three different water solubility corre-lations. Print the K-values for one of the VLE flash units and for the VLLE flash.

This exercise allows you to answer the following questions:

■ Is the assumption of a pure water phase valid for this simulation?

■ How do the results vary with respect to the water solubility correla-tions?

Table 15: Feed Stream DataPure Components Rate

(lb moles/hr)Petroleum Components

Rate (lb moles/hr)

Water 3000 Cut 11 165

Carbon Dioxide 35 Cut 12 303

Nitrogen 30 Cut 13 560

Methane 890 Cut 14 930

Ethane 300 Cut 15 300

Propane 520

i-Butane 105

n-Butane 283

i-Pentane 100

n-Pentane 133

Temperature 150°F

Pressure 1000 psia

Table 16: Petroleum Fraction PropertiesFraction Molecular Wt. API Gravity NBP(°F)

Cut 11 91 64 180

Cut 12 100 61 210

Cut 13 120 55 280

Cut 14 150 48 370

Cut 15 200 40 495


✔ SOLUTION Defining four thermodynamic sets allows PRO/II to flash the feed iso-thermally four times within one simulation run.

Figure 33 shows the Flash Drum Summary, which only reports the water decant flashes. There are three FLASH DRUMs, one for each of the solubil-ity correlations: SIMSCI, KEROSENE, and EOS. PRO/II reports the total liquid mole fraction and breaks down the liquid phases into the liquid hydrocarbon phase and the free water phase. Note that PRO/II provides this type of report only when you invoke the water decant option for a hydrocarbon-water system. You can observe that the three solubility methods produce very similar results for this problem.

The K-value printout for the first FLASH unit (DCNT-SIMSCI) follows the standard Flash Drum Summary. This report gives the vapor and liquid mole fractions and the K-value for each component, providing you with information about the relative volatilities of the components of the prod-ucts. If you choose to lump the vapor and liquid phases into one product, you can obtain the relative compositions of the different phases in the product.

Figure 33: Flash Drum Summary

with K-Value Report

FLASH ID DCNT-SIMSCI DECANT-KERO DECANT-EOS

NAME

FEEDS CRUDE CRUDE_R2 CRUDE_R1

PRODUCTS VAPOR 1V 2V 3V LIQUID 1L 2L 3L WATER 1W 2W 3W TEMPERATURE, F 300.000 300.000 300.000 PRESSURE, PSIA 300.000 300.000 300.000 PRESSURE DROP, PSI 700.000 700.000 700.000 MOLE FRAC VAPOR 0.33552 0.33467 0.34579 MOLE FRAC TOTAL LIQUID 0.66448 0.66533 0.65421 MOLE FRAC H/C LIQUID 0.35887 0.36147 0.35919 MOLE FRAC FREE WATER 0.30561 0.30386 0.29502 DUTY, MM BTU/HR 59.02614 58.96749 60.00998 FLASH TYPE ISOTHERMAL ISOTHERMAL ISOTHERMAL

VAPOR-LIQUID COMPOSITIONS AND K-VALUES FOR UNIT 1, 'DCNT-SIMSCI' COMPONENT VAPOR LIQUID K-VALUE ------------------- ---------- ---------- ---------- 1 WATER 0.22197 0.03308 6.7112E+00 2 CO2 0.01219 0.00135 9.0594E+00 3 N2 0.01127 3.8836E-04 2.9011E+01 4 C1 0.32055 0.02432 1.3183E+01 5 C2 0.09736 0.01819 5.3508E+00 6 C3 0.14613 0.05268 2.7737E+00 7 IC4 0.02518 0.01468 1.7148E+00 8 NC4 0.06314 0.04399 1.4352E+00 9 IC5 0.01754 0.02001 8.7627E-01 10 NC5 0.02171 0.02812 7.7196E-01 11 CUT11 0.01434 0.04666 3.0732E-01 12 CUT12 0.02020 0.09143 2.2090E-01 13 CUT13 0.01813 0.18693 9.6967E-02 14 CUT14 0.00981 0.32940 2.9796E-02 15 CUT15 4.8360E-04 0.10877 4.4463E-03

36 Hydrocarbon-Water Phase Separation

Figure 34 shows the three-phase Flash Drum Summary from the output report. Note that this summary only reports the rigorous VLLE FLASH

units. If you invoke the VLLE option for a FLASH, but only one liquid phase exists, then PRO/II provides the results in the standard Flash Drum Summary. The results for the rigorous three-phase FLASH are very similar to those in Figure 33. The vapor and liquid mole fractions for each component in the three product phases are at the end of the standard three-phase Flash Drum Summary. PRO/II uses these results to calculate the two sets of K-values. You can obtain a set of LLE K-values by divid-ing the second set of VLE K-values by the first.

Figure 34: Three-Phase Flash

Drum Summary with K-Value Report

FLASH ID RIG-SRKKD NAME FEEDS CRUDE_R3 PRODUCTS VAPOR 4V LIQUID 1 4L LIQUID 2 4W TEMPERATURE, F 300.000 PRESSURE, PSIA 300.000 PRESSURE DROP, PSI 700.000 MOLE FRAC VAPOR 0.34778 MOLE FRAC TOTAL LIQUID 0.65222 MOLE FRAC LIQUID 1 0.36325 MOLE FRAC LIQUID 2 0.28897 DUTY, MM BTU/HR 61.47417 FLASH TYPE ISOTHERMAL VAPOR-LIQUID COMPOSITIONS AND K-VALUES FOR UNIT 4, 'RIG-SRKKD' ---------- COMPOSITIONS ---------- COMPONENT VAPOR LIQUID 1 LIQUID 2 ------------------- ---------- ---------- ---------- 1 WATER 0.23782 0.05616 0.99963 2 CO2 0.01174 0.00131 5.3824E-05 3 N2 0.01087 3.8351E-04 3.2828E-06 4 C1 0.30942 0.02371 1.8329E-04 5 C2 0.09437 0.01751 3.9243E-05 6 C3 0.14269 0.05037 5.0834E-05 7 IC4 0.02481 0.01401 3.3863E-06 8 NC4 0.06243 0.04199 1.8011E-05 9 IC5 0.01757 0.01914 2.1698E-06

10 NC5 0.02183 0.02693 3.2412E-06 11 CUT11 0.01477 0.04520 5.6747E-06 12 CUT12 0.02102 0.08885 5.4152E-06 13 CUT13 0.01933 0.18291 1.4512E-06 14 CUT14 0.01079 0.32417 9.1229E-08 15 CUT15 5.5476E-04 0.10737 5.4406E-11

------ K-VALUES ------ COMPONENT VAP/LIQ 1 VAP/LIQ 2 ------------------- ---------- ---------- 1 WATER 4.2353E+00 2.3793E-01 2 CO2 8.9758E+00 2.1803E+02 3 N2 2.8327E+01 3.3092E+03 4 C1 1.3048E+01 1.6877E+03 5 C2 5.3874E+00 2.4042E+03 6 C3 2.8323E+00 2.8063E+03 7 IC4 1.7703E+00 7.3241E+03 8 NC4 1.4865E+00 3.4657E+03 9 IC5 9.1766E-01 8.0958E+03 10 NC5 8.1044E-01 6.7340E+03 11 CUT11 3.2684E-01 2.6030E+03 12 CUT12 2.3656E-01 3.8813E+03 13 CUT13 1.0566E-01 1.3317E+04 14 CUT14 3.3278E-02 1.1825E+05 15 CUT15 5.1668E-03 1.0197E+07


Table 17 compares the different product flowrates for each of the four flash types. Note that PRO/II breaks down the two liquid phases into hydrocarbon and water content. For this example the second liquid (water) phase contains only 0.04 mol % (0.9/2211.7) of hydrocarbon. All three solubility correlations give similar results for the total flowrate of each product. The rigorous three-phase FLASH with SRKKD thermo-dynamics results in significantly more water in the hydrocarbon phase and thus less water in the water-dominated phase, than any of the three VLE FLASH units with water decant.

The best method for selecting a VLLE or a VLE thermodynamic system with a water solubility correlation is to compare the simulation results of each system with actual process data. Since this is not always possible, the PRO/II Keyword Manual and the PRO/II Reference Manual provide guidelines for the selection of an appropriate thermodynamic system and water solubility correlation.

Table 17: Comparison of VLE and VLLE Flash Results

Flowrate (lb-mol/hr)

Water Solubility Method

SIMSCI KEROSENE EOS RIGOROUS

Vapor 2568.1 2561.6 2646.7 2661.9

Liquid 1HydrocarbonWater

2746.82655.990.9

2766.72661.1105.6

2749.22626.0123.2

2780.52624.4156.1

Liquid 2WaterHydrocarbon

2339.12339.10.0

2325.82325.80.0

2258.12258.10.0

2211.62210.80.8

38 Hydrocarbon-Water Phase Separation

Naphtha Assay - Part 1

TASK Enter the assay data for the naphtha feed described below and generate a set of petroleum components. Also create a plot of the calculated TBP curve and component cuts. The light ends make up 5% of the total liquid volume. Use SRK thermodynamics with API liquid density to model the system.

To represent the boiling curve more closely, increase the number of pseudocomponents by using twenty-one 18°F (10°C) cuts from 80°F to 460°F (30°C to 240°C). The process data is given in Table 18.

✔ SOLUTION Build the flowsheet and enter the UOM, components, and thermody-namic data, as usual.

Step 1 Modify the Assay Characterization DataTo represent the boiling curve more closely, you must increase the num-ber of pseudocomponents by using twenty-one 18°F (10°C) cuts from 80°F to 460°F (30°C to 240°C).

➤ Click the Assay Characterization button on the toolbar.

➤ Click .

Table 18: Naphtha Feed DataASTM D86 Data Light Ends

LV% T(°F) T(°C) Component Mole %

3 90 32 isobutane 0.70

5 125 52 butane 2.15

10 195 90 isopentane 0.86

30 250 121 pentane 3.58

50 280 138

70 310 154 Total 5% liq. volume

90 390 199

95 418 214

98 430 221

Flowrate 1000 lb/hr 450 kg/hr


Pressure 1 atm

Average API gravity 54.2 Average Specific Gravity 0.762

Modify Primary Set...


➤ In the Primary TBP Cutpoints Definition dialog box, change the Minimum Temperature for First Interval to 80°F (30°C).

➤ In first row, enter 460°F (240°C) as the Maximum Temperature for the Interval and 21 as the Number of Pseudocomponents in Interval. Leave the default data for the second and third intervals as they are.

➤ Click to return to the Assay Cutpoints and Characterization Options dialog box.

➤ Click and change the Initial Point from its default to 3%, and Distillation Curve Interconversion to API 1994.

➤ Close the windows by Clicking .

Step 2 Define the Assay Stream

➤ Add a stream into the flowsheet and double-click on the stream and select Petroleum Assay as the Stream Type.

➤ Click and enter the rate.

To define a new assay:

➤ In the Stream Data - Flowrate and Assay dialog box, click .

➤ Choose ASTM D86 and enter the distillation data in the grid. You can use the <Tab> key to move from cell to cell in the grid.

➤ Select API Gravity and enter the average value.

Figure 35 shows these entries.

Figure 35: Assay Definition

OK


OK

Flowrate and Assay...

Define/Edit Assay...

40 Naphtha Assay - Part 1

To enter the lightends composition:

➤ In the Assay Definition dialog box, click .

➤ Choose Percent of Assay and enter 5 as the LV percent figure.

➤ Check the box next to Assay lightends information for stream NAPHTHA_FEED and enter the molar composition of each compo-nent in the grid.

➤ Because the lightends compositions do not add up to 1 or 100, you must check the Normalize box.

Figure 36 shows these entries.

Figure 36: Assay Lightends Data

➤ Back in the Stream Data dialog box, enter Temperature and Pres-sure values. Click to return to the flowsheet.

You will be asked whether you want to generate the pseudocomponents now or at a later time. Answer No.

Step 3 Generate the PseudocomponentsIf you have not already generated the pseudocomponents, you can do so at any time by selecting Input/Generate Assay Components from the menu bar. Then:

■ To view the list of pseudocomponents, open the Component Selec-tion dialog box.

■ To look at the petroleum property data generated for the pseudocom-ponents, generate an output report and view it.

Lightends...

OK


Figure 37: Component Summary

■ To view assay processing curve, click in the Assay Definition dialog box.

Figure 38: Assay Processing

Plot

Step 4 Save and Close the SimulationPlease save this simulation as NAPHTH1.PRZ and you will use this simu-lation in the next exercise.

View Curve...



TASK In this exercise you will use the assay stream you created in NAPHTH1and manipulate it using two flash drums. The first flash drum predicts the temperature at which 80% of the feed is recovered in the vapor. The second flash drum predicts the quantity of liquid that drops out when a temperature drop is imposed on that vapor.

✔ SOLUTION Open the simulation named NAPHTH1.PRZ and save it under a new name, NAPHTH2.PRZ.

Step 1 Build the Process Flow Diagram

➤ Add two flash drums to the flowsheet and connect, as shown below.

➤ Connect the stream NAPHTHA_FEED to the first flash drum.

Figure 39: PRO/II Flowsheet

Step 2 Enter Unit Operating ConditionsEnter unit data from Table 19 into both flash drums.

Express the recovery specification in Flash F1 as the ratio of one stream's flowrate to that of another. You can define a recovery on the basis of one component or a range of components or, as here, on the total stream. Set the specification so that it matches the figure shown below.

Table 19: Equipment Data and Operating ConditionsUnit Description Data

D-1 Flash drum Pressure = 0.8 atm 80 / 20 vapor/liquid split

D-2 Flash drum Temperature Drop = 18°F (10°C) Pressure Drop = 0.1 atm


Because the feed temperature of flash F2 is unknown until the first flash has executed, you cannot enter an absolute value at this time. You can, however, enter a relative value, as shown below.


➤ Add a STREAM PROPERTY TABLE to display a Short Property List for all the streams in the flowsheet.

➤ Run the simulation and observe the temperatures, pressures and flowrates on the STREAM PROPERTY TABLE. Verify that they accu-rately reflect the specifications you entered.

Figure 40: Short Property Table

Step 4 Save and Close the SimulationPlease save this simulation as NAPHTH2.PRZ and you will use this simu-lation in the next exercise.



TASK Using the assay stream and flashes from NAPHTH2, you will now exam-ine the effects of varying the vapor/liquid split in the first flash drum on the duty of the second flash drum. Run cases at vapor fractions from 80% (the base case) to 40% in 10% increments.

✔ SOLUTION Open the simulation named NAPHTH2.PRZ and save it under a new name, NAPHTH3.PRZ.

Step 1 Enter Case Study Data

➤ Click the Case Study button on the toolbar to open the Case Study Parameters and Results dialog box.

➤ Check the Define Case Study box.

➤ In the first row of the Parameter field, click Parameter.

➤ Select Flash from the Unit/Stream list, F1 from the Unit Name list.

➤ Click Parameter and select Product Specification.

➤ Specify 5 cycles and a step size of -0.1.

➤ In the first row of the Result field, click Parameter and select Flash F2 Duty.

Figure 41 shows the completed dialog box.

Figure 41: Completed Case

Study Parameters Dialog Box


Step 2 Run the Simulation

➤ Click the Run button to run the simulation.

Step 3 View Output in a Tabular Format

➤ Select Output/Case Study from the menu bar and then Tables from the submenu to open the Case Study Tables dialog box.

➤ Enter a table name in the first row and click .

➤ Move the variables you want to appear in the table from the Avail-able Variables list to the Selected Variables list.

➤ Click on Columns to change the default to Display cycles in Rows.

➤ Click to view the results.

Figure 42: Case Study Results in

a Tabular Format

Step 4 View Output in a Graphical FormatDefine a plot that shows the change in F2 duty with the change in F1 split.

➤ Select Output/Case Study from the menu bar and then Plots from the submenu to open the Case Study Plots dialog box.

➤ Enter a plot name in the first row and click .

➤ Highlight F1SPLIT from the Available Variables list and X-Axisfrom the other list.

➤ Enter a label in the Label/Legend field, if desired.

➤ Click , followed by .

➤ Highlight F2DUTY from the Available Variables list and Y-Axis#1in the other list.

➤ Enter a label in the Label/Legend field, if desired.

➤ Click , followed by .

Data...

View Table...

Data...

Update Add ->

Update Add ->


Figure 43: Case Study - Plot

Definition Dialog Box

➤ To view the plot, click .

Figure 44: F2 Duty as a Function

of F2 Liquid/Vapor Ratio

Step 5 Save and Close the SimulationPlease save this simulation as NAPHTH3.PRZ.

Preview Plot...


Phase Envelope

TASK A vapor stream normally condenses when you increase pressure and/or decrease temperature. Under certain conditions, however, it is possible for a vapor stream to undergo partial condensation as its pressure is reduced (at a fixed temperature) or as its temperature is increased (at a fixed pressure). This counter-intuitive phenomenon, called retrograde condensation, is particularly important in the production of petroleum from deep gas wells.

Typically, as a gas is brought to the surface its pressure decreases until it matches that of the receiving vessel, which is at ambient temperature. The pressure of the vessel is set to lie in the two-phase region at that temperature so that partial condensation of the gas occurs. The con-densed liquid, enriched in the more-valuable heavy components, is recovered. The remaining vapor is repressurized and injected back into the well.

Figure 45: Petroleum Recovery

from a Deep Gas Well

GasT = 150ºFP = 2500 psia

Table 20: Feed Stream DataComponent Mole %

C1 82

C2 7

C3 4

IC4 2

NC4 2

IC5 and heavier 3

Flowrate 100 lb-mole/hr 45 kg-mole/hr



48 Phase Envelope

You want to examine the characteristics of the gas in the receiving ves-sel so that you can make a decision about the pressure required to maxi-mize the amount of liquid condensed.

Generate a phase envelope plot for the feed stream. Also generate lines of constant liquid mole fraction at 5%, 10% and 15%.

At an ambient temperature of 50°F (10°C), what pressure will be needed to maximize the production of liquid?

✔ SOLUTION After defining the components and thermodynamic method, add a stream to the flowsheet and enter stream data. Add a Phase Envelope to the flowsheet.

In the Phase Envelope dialog box, select the feed stream in the first row of the grid. In the second row, select the feed stream and enter a Liquid Mole Fraction of 0.05. In the same way, enter the other liquid mole frac-tions in rows three and four. Click on , change Individualto Comparison for each curve, and enter 1 through 5 for Plot Symbols.

Plot five graphs: one for each of the plots and one showing all the plots together. Run the simulation. Select Output/Generate Plot... from the menu bar and plot the phase envelope.

The resulting phase envelope for this exercise is shown below.

Figure 46: Phase Envelope, PH1

Plot Options


Compressor Curves

TASK Set up a simulation of part of a refrigeration loop. The flowsheet, stream and process data are shown below.

Figure 47: Refrigeration Loop

Flowsheet

Compressor

Separator

8

1 32

Vaporizor

Valve Cooler

Surge

4

5 6

7

Table 21: Feed Stream DataComponent Mole%

Ethane 1.04

Propane 96.94

i-Butane 1.68

n-Butane 0.34

Total Flowrate 16500 lb-mol/hr 7485 kg-mol/hr

Temperature 15.5°F -9.2°C


Table 22: Equipment Data and Operating ConditionsUnit Data

Valve Outlet pressure 87 psia 600 kPa

Cooler Hotside: Process stream duty Pressure drop

2x106 BTU/hr 4.4 psi

2.11x106 kJ/hr 30 kPa

Separator Adiabatic flash, zero pressure drop

Vaporizer Coldside: Pressure drop

Process stream product at dew point 8.8 psi 61 kPa

Surge Mixer. Outlet pressure 65 psia 450 kPa

Compressor Curves Flowrate (ft3/hr) (m3/hr)

Actual Head (ft) (m)

Adiabatic Efficiency

900000 25485 38000 11582 69

1000000 28317 37000 11278 71

1240000 35113 35300 10760 72

1360000 38511 33100 10089 73

1430000 40493 27250 8306 71

50 Compressor Curves

✔ SOLUTION Place the minimum number of units on the PFD.

Name the units and streams so that the flowsheet looks like Figure 48.

Figure 48: Modified Flowsheet

In the Compressor dialog box, select Actual Head Curve and click . Enter the table of Volumetric Flowrate against Head

and click . Select Single Adiabatic Efficiency Curve from the Effi-ciency or Temperature Specification list and enter the efficiency data.

Hint: You can reduce the number of units by combining the cooler and separator. You cannot feed streams 4 and 6 directly into the compressor because the surge mixer has an outlet pressure specification.

V1H2

H3

M1

C1

1 2

4

56

7

8

Enter Curve... OK

Figure 49: Compressor C1

ResultsEnglish Units

User Input Calculated ---------- ---------- Outlet Temperature, F 182.39 Outlet Pressure, PSIA 321.54 Pressure Increase, PSI 256.54 Actual Work, HP 13099.77 Head, FT 35525.17 Adiabatic Efficiency 71.89 Polytropic Efficiency 75.26

Metric Units

User Input Calculated ---------- ---------- Outlet Temperature, C 83.55 Outlet Pressure, KPA 2216.81 Pressure Increase, KPA 1768.65 Actual Work, KW 9769.40 Head, M 10828.02 Adiabatic Efficiency 71.89 Polytropic Efficiency 75.26


Debutanizer

TASK A debutanizer removes C4 and lighter components from a mixed Naph-tha and LPG feed stream. The Naphtha feed has been changed and you must ensure that the column can still meet the process requirements such as product recoveries and column duties.

Figure 50: Debutanizer Process

All the data required for this simulation are summarized in the tables below.

OVHD

BTMS

Naphtha

LPG

338ºF15

32

1

270 psia

Table 23: LPG Feed DataComponent Mole %

H2 0.3

H2S 0.2

C1 0.7

C2 5.5

C3 28.5

IC4 11.7

NC4 49.0

IC5 4.1



Flowrate 400 ft3/hr 11.3 m3/hr

52 Debutanizer

The VLE and enthalpies of natural gas systems are generally modeled well by equations of state such as Peng-Robinson or Soave-Redlich-Kwong. However, these methods are less good at predicting liquid den-sity so a different method, such as COSTALD or API, should be used.

Table 24: Naphtha Feed DataASTM D86 Data

Liquid Volume % Temperature (°F) (°C)

0 104 40

5 144 62

10 158 70

30 196 91

50 228 109

70 248 120

90 284 140

95 311 155

100 329 165

Average Specific Gravity = 0.75

Lightends Data

Component Liquid Volume %

C3 0.07

IC4 0.21

NC4 0.42

IC5 3.24

NC5 6.06

10% liquid volume of assay



Flowrate 3200 ft3/hr 90 m3/hr

Table 25: Column Operating ConditionsFeed Temperature 338°F 170°C

Condenser Type Bubble Point

Condenser Pressure 185 psia 1275 kPa

Top Tray Pressure 190 psia 1310 kPa

Column Pressure Drop 4.3 psi 30 kPa

Reboiler Type Kettle

Hint: Use the Define feature to set the overhead rate from the col-umn as all the C4 and lighter components in the column feed.


Answer the following questions:

1. Can the column still recover 99% of the C4 components overhead with a loss of only 1% of the C5 components?

2. What are the duties on the condenser and reboiler?

3. What is the reflux ratio?

✔ SOLUTION As the column has converged with the required recovery specifications, it can clearly cope with the new service.

Table 26: Results for Both English and Metric InputEnglish Metric

Duties (x 106)

Condenser -11.8808 Btu/hr -12.2126 kJ/hr

Reboiler 16.7205 Btu/hr 17.2770 kJ/hr

Reflux Ratio 4.4086 4.2643

54 Debutanizer


TASK An existing heat exchanger runs with a shellside outlet temperature of 161°F. You want to increase the throughput of the exchanger and need to calculate the shellside outlet temperature under the new conditions. Set up the simulation of the exchanger. This exercise is in two parts:

Part A Determine the fouling of the heat exchanger under present operating conditions.

Part B Using the fouling results from Part A, rate the existing fouled exchanger for the increased throughput.

The flowsheet, stream and process data are provided below.

Figure 51: Schematic of a Rigorous Heat

ExchangerBT1

FD1

FD2

BT2

EA1

Table 27: Feed Stream DataComponent FD1 Mole % BT1 Mole %

NC4 15 4

IC5 14 15

NC5 16 16

NC6 22 25

NC7 13 15

NC8 20 25

Temperature 70°F 220°F

Pressure 195 psia 135 psia

Current Flowrate 550000 lb/hr 500000 lb/hr

Increased Flowrate 606000 lb/hr 660000 lb/hr


Heat Exchanger Data

56 Rigorous Heat Exchanger

✔ SOLUTION

Part A Determine the fouling of the heat exchanger under current operating conditions. In this part of the exercise, you require a shellside outlet tem-perature of 161°F.

Build the flowsheet and enter the UOM, components, and thermody-namic data, as usual. Enter stream data.

Step 1 Enter Unit DataIn this example, the shellside outlet temperature is given and we want to determine the fouling resistance. Select Shell Outlet Temperature from the list and enter the value in the Temperature field.

➤ Click each button and enter the appropriate data. Fields outlined in green means that, if you do not enter a value, PRO/II calculates one.

➤ In the Film Coefficients dialog box, set the tubing fouling resistance to 0.

You want PRO/II to calculate an overall fouling resistance to meet the specification. You could supply values for both the tubeside and a shell-side fouling resistances and have PRO/II adjust them to meet the perfor-mance specification. However, for simplicity, it is easier to set the tubeside fouling resistance to zero and allow PRO/II to report the calcu-lated overall resistance as the required shellside resistance.

➤ Click to check the Extended box to request an addi-tional data sheet with information about stream properties, heat exchanger configuration and hydrodynamics.

➤ Run the simulation and view the results. Make a note of the required shellside fouling resistance.

Print Options...


Part B Using the fouling results you have just calculated, rate the existing fouled exchanger for the increased throughput.

➤ Change the flowrates of both feed streams.

➤ Click , and enter the new value for the shellside fouling resistance calculated in Part A.

➤ In the Rigorous Heat Exchanger main dialog box, change the Calcu-lation Type to Rating (Predictive).

➤ Run the simulation and view the results. Note the tubeside and shell-side exit temperatures.


Results - Part A

SHELL AND TUBE EXCHANGER DATA SHEET FOR EXCHANGER 'E1' I--------------------------------------------------------------------I I EXCHANGER NAME UNIT ID E1 I I SIZE 36 - 240 TYPE AES HORIZONTAL CONNECTED 1 PARALLEL 1 SERIES I I AREA/UNIT 2295. FT2 ( 1984.FT2 REQUIRED ) AREA/SHELL 2295. FT2 I I--------------------------------------------------------------------I I PERFORMANCE OF ONE UNIT SHELL-SIDE TUBE-SIDE I I--------------------------------------------------------------------I I FEED STREAM ID BT1 FD1 I I FEED STREAM NAME I I TOTAL FLUID LB/HR 500000. 550000. I I VAPOR (IN/OUT) LB/HR / / I I LIQUID LB/HR 500000./500000. 550000./550000. I I STEAM LB/HR / / I I WATER LB/HR / / I I NON CONDENSIBLE LB/HR I I TEMPERATURE (IN/OUT) DEG F 220.0 / 161.0 70.0 / 129.8 I I PRESSURE (IN/OUT) PSIA 135.00 / 133.26 195.00 / 189.64 I I--------------------------------------------------------------------I I SP. GR., LIQ (60F/60F H2O) 0.662 / 0.662 0.653 / 0.653 I I VAP (60F/60F AIR) / / I I DENSITY, LIQUID LB/FT3 35.822 / 38.094 40.509 / 38.539 I I VAPOR LB/FT3 / / I I VISCOSITY, LIQUID CP 0.147 / 0.210 0.289 / 0.220 I I VAPOR CP / / I I THRML COND,LIQ BTU/HR-FT-F 0.0587 / 0.0654 0.0754 / 0.0687 I I VAP BTU/HR-FT-F / / I I SPEC.HEAT,LIQUID BTU/LB-F 0.6317 / 0.5937 0.5328 / 0.5759 I I VAPOR BTU/LB-F / / I I LATENT HEAT BTU/LB I I VELOCITY FT/SEC 1.12 6.93 I I DP/SHELL PSI 1.74 5.36 I I FOULING RESIST HR-FT2-F/BTU 0.00200 ( 0.00343 REQD) 0.00000 I I--------------------------------------------------------------------I I TRANSFER RATE BTU/HR-FT2-F SERVICE 109.64 (94.78 REQD)CLEAN 140.43 I I HEAT EXCHANGED MM BTU/HR 18.207 MTD(CORRECTED) 83.7 FT 0.924 I I--------------------------------------------------------------------I I CONSTRUCTION OF ONE SHELL SHELL-SIDE TUBE-SIDE I I--------------------------------------------------------------------I I DESIGN PRESSURE PSIA 300. 300. I I NUMBER OF PASSES 1 2 I I MATERIAL CARB STL CARB STL I I INLET NOZZLE ID IN 8.0 8.0 I I OUTLET NOZZLE ID IN 8.0 8.0 I I--------------------------------------------------------------------I I TUBE: NUMBER 600 OD 0.750 IN BWG 14 LENGTH 20.0 FT I I TYPE BARE PITCH 1.3 IN PATTERN 60 DEGREES I I SHELL: ID 36.00 IN SEALING STRIPS 0 PAIRS I I BAFFLE: CUT 0.300 SPACING (IN/CENT/OUT): IN 24.0/24.0/24.0,SINGLE I I RHO-V2: INLET NOZZLE 4419.5 LB/FT-SEC2 I I TOTAL WEIGHT/SHELL,LB 10393.6 FULL OF WATER 30135.8 BUNDLE 11825.0 I I--------------------------------------------------------------------I

Film Coefficients...

58 Rigorous Heat Exchanger


Results - Part B

SHELL AND TUBE EXCHANGER DATA SHEET FOR EXCHANGER 'E1' I--------------------------------------------------------------------I I EXCHANGER NAME UNIT ID E1 I I SIZE 36 - 240 TYPE AES HORIZONTAL CONNECTED 1 PARALLEL 1 SERIES I I AREA/UNIT 2295. FT2 AREA/SHELL 2295. FT2 I I--------------------------------------------------------------------I I PERFORMANCE OF ONE UNIT SHELL-SIDE TUBE-SIDE I I--------------------------------------------------------------------I I FEED STREAM ID BT1 FD1 I I FEED STREAM NAME I I TOTAL FLUID LB/HR 660000. 606000. I I VAPOR (IN/OUT) LB/HR / / I I LIQUID LB/HR 660000. / 660000. 606000. / 606000. I I STEAM LB/HR / / I I WATER LB/HR / / I I NON CONDENSIBLE LB/HR I I TEMPERATURE (IN/OUT) DEG F 220.0 / 170.1 70.0 / 130.9 I I PRESSURE (IN/OUT) PSIA 135.00 / 131.96 195.00 / 188.64 I I--------------------------------------------------------------------I I SP. GR., LIQ (60F/60F H2O) 0.662 / 0.662 0.653 / 0.653 I I VAP (60F/60F AIR) / / I I DENSITY, LIQUID LB/FT3 35.822 / 37.762 40.509 / 38.500 I I VAPOR LB/FT3 / / I I VISCOSITY, LIQUID CP 0.156 / 0.193 0.293 / 0.212 I I VAPOR CP / / I I THRML COND,LIQ BTU/HR-FT-F 0.0535 / 0.0578 0.0677 / 0.0609 I I VAP BTU/HR-FT-F / / I I SPEC.HEAT,LIQUID BTU/LB-F 0.6417 / 0.6008 0.5328 / 0.5767 I I VAPOR BTU/LB-F / / I I LATENT HEAT BTU/LB I I VELOCITY FT/SEC 1.48 7.64 I I DP/SHELL PSI 3.04 6.36 I I FOULING RESIST HR-FT2-F/BTU 0.00343 0.00000 I I--------------------------------------------------------------------I I TRANSFER RATE BTU/HR-FT2-F SERVICE 100.20 CLEAN 152.66 I I HEAT EXCHANGED MM BTU/HR 20.443 MTD(CORRECTED) 88.9 FT 0.940 I I--------------------------------------------------------------------I I CONSTRUCTION OF ONE SHELL SHELL-SIDE TUBE-SIDE I I--------------------------------------------------------------------I I DESIGN PRESSURE PSIA 300. 300. I I NUMBER OF PASSES 1 2 I I MATERIAL CARB STL CARB STL I I INLET NOZZLE ID IN 8.0 8.0 I I OUTLET NOZZLE ID IN 8.0 8.0 I I--------------------------------------------------------------------I I TUBE: NUMBER 600 OD 0.750 IN BWG 14 LENGTH 20.0 FT I I TYPE BARE PITCH 1.3 IN PATTERN 60 DEGREES I I SHELL: ID 36.00 IN SEALING STRIPS 0 PAIRS I I BAFFLE: CUT 0.300 SPACING (IN/CENT/OUT): IN 24.0/26.54/24.0,SINGLE I I RHO-V2: INLET NOZZLE 7700.6 LB/FT-SEC2 I I TOTAL WEIGHT/SHELL,LB 10393.6 FULL OF WATER 30135.8 BUNDLE 11825.0 I I--------------------------------------------------------------------I


Two Stage Compressor

TASK A natural gas stream is compressed before entering a pipeline. The stream is first compressed to 12 bar and then to 26 bar. Liquid condenses in the compressor aftercoolers and is recycled back to the previous stage. The liquid product is removed from the feed flash.

Figure 54: Two Stage

Compressor Flowsheet

Use the Peng-Robinson thermodynamic method with the COSTALD correlation for liquid density.

All the data required for this simulation are summarized in the tables below.

D-3

C-1

HX-1D-2D-1

Feed

C-2

HX-2

Vapor

Liquids

S2

S1

S3 S7 S11

S4 S5 S6 S8 S9 S10

100ºF70 psia

Table 28: Feed Stream DataComponent Flowrate

(lb-mol/hr) (kg-mol/hr)

Nitrogen 400 180

Carbon dioxide 4230 1920

Methane 32000 14520

Ethane 20000 9070

Propane 16000 7260

i-Butane 1700 770

n-Butane 6200 2810

i-Pentane 2100 950

n-Pentane 3600 1630

n-Hexane 3400 1540

C7 Plus (model as NC9) 7000 3180


Pressure 70 psia 5 bar

60 Two Stage Compressor

Part A Answer the following questions:

1. What are the amounts of liquid and vapor leaving the process?

2. What compressor work is required for each stage?

3. What are the stream temperatures entering the aftercoolers?

4. What are the aftercooler duties?

Part B If you have time, answer the following questions:

1. Can the same information still be obtained with fewer units in the flowsheet? If so, simulate it and check that the data are available and that the values are the same as in the original calculation.

2. Assuming that you only want to know the product streams from the process, simulate the process with the minimum number of units required.

✔ SOLUTION

Part A The actual work is 43808 HP (32456 kW) for C-1 and 42804 HP (30893 kW) for C-2.

The temperatures entering the aftercooler are shown on the compressor output and on the stream results. They are 196.5°F (93.3°C) for C-1 and 214.9°F (103.7°C) for C-2.

The aftercooler duties are 80.1x106 Btu/hr (82.9x106 kJ/hr) for HX-1 and 153.9x106 Btu/hr (152.6x106 kJ/hr) for HX-2.

Table 29: Unit Operating ConditionsCompressor C-1

Outlet Pressure 170 psia 12 bar

Adiabatic Efficiency 74% 74%

Compressor C-2

Outlet Pressure 380 psia 26 bar

Adiabatic Efficiency 72% 72%

Heat Exchanger HX-1

Exit Temperature 135°F 60°C

Pressure Drop 5 psi 0.35 bar

Heat Exchanger HX-2

Exit Temperature 135°F 60°C

Pressure Drop 5 psi 0.35 bar


Figure 54 shows the stream summaries for the liquid outlet stream, S3, and the vapor outlet stream, S10.

Part B 1. The heat exchangers are not required. You could omit these and use the aftercooler option on the compressor. All the information requested is still available.

2. If you only need the product stream information, compressor C-2 (and its aftercooler) may be removed. Set the flash D-3 to the condi-tions leaving the aftercooler and the products will be identical. You cannot remove C-1 as the temperature of D-2 is unknown. Liquid from D-3 is flashed into the drum and reduces the temperature below the aftercooler exit temperature. However, to simplify the flowsheet, C-1 and its aftercooler could be replaced by a flash drum.

Figure 55: Stream Summary for Streams S3 and S10

English Units

STREAM 'S3' TOTAL ----------RATE, LB-MOL/HR 15629.9004TEMPERATURE, F 98.66PRESSURE, PSIA 70.00 MOLAR FLOWRATES, LB-MOL/HR 1 - N2 0.5471 2 - CO2 45.8175 3 - C1 141.4767 4 - C2 486.4024 5 - C3 1178.3664 6 - IC4 273.1566 7 - NC4 1308.8244 8 - IC5 847.2167 9 - NC5 1682.4803 10 - NC6 2667.2460 11 - NC9 6998.3663

STREAM 'S10' TOTAL ----------RATE, LB-MOL/HR 80988.7220TEMPERATURE, F 135.00PRESSURE, PSIA 375.00 MOLAR FLOWRATES, LB-MOL/HR 1 - N2 399.4505 2 - CO2 4184.0733 3 - C1 31858.0695 4 - C2 19512.5552 5 - C3 14819.5615 6 - IC4 1426.3681 7 - NC4 4889.0529 8 - IC5 1251.3970 9 - NC5 1915.0068 10 - NC6 731.0926 11 - NC9 2.0944

Metric Units

STREAM 'S3' TOTAL ----------RATE, KG-MOL/HR 6929.9789TEMPERATURE, C 40.00PRESSURE, BAR 5.00 MOLAR FLOWRATES, KG-MOL/HR 1 - NITROGEN 0.2451 2 - CO2 20.1492 3 - METHANE 63.1166 4 - ETHANE 211.7885 5 - PROPANE 505.7845 6 - IBUTANE 115.6366 7 - NBUTANE 552.4385 8 - IPENTANE 354.3091 9 - PENTANE 704.4548 10 - HEXANE 1124.4488 11 - NC9 3177.6072

STREAM 'S10' TOTAL ----------RATE, KG-MOL/HR 36995.6775TEMPERATURE, C 60.00PRESSURE, BAR 25.65 MOLAR FLOWRATES, KG-MOL/HR 1 - NITROGEN 179.7539 2 - CO2 1899.8059 3 - METHANE 14456.6954 4 - ETHANE 8857.7931 5 - PROPANE 6752.4271 6 - IBUTANE 654.1972 7 - NBUTANE 2256.8271 8 - IPENTANE 595.2574 9 - PENTANE 924.7489 10 - HEXANE 414.5482 11 - NC9 2.6230

62 Two Stage Compressor

Propylene Chlorination Reactor

TASK In a propylene chlorination plant, chlorine reacts with propylene to pro-duce allyl chloride, 1,2-dichloropropane, 1,3-dichloropropene and hydrogen chloride. The reaction takes place at 800°F (425°C) and 70 psia (5 kg/cm2) in a homogeneous gas phase reactor and the resulting products are separated in a fractionation section. Most of the unreacted propylene is recycled back to the reactor. The reactor volume is 10 ft3

(0.3 m3). For a product flowrate estimate, let’s assume that nearly all the chlorine is converted, i.e., Cl2 in S13 = 1% CL2 flowrate.

Figure 56: Propylene

Chlorination Reactor

The flowsheet, stream and process data are shown below. Use Soave-Redlich-Kwong thermodynamics with Costald liquid densities.

PRPL

CL2

CST1

PROD

Table 30: Feed Stream DataPRPL CL2

Composition 100% proplylene 100% chlorine

Flowrate 220 lb-moles /hr 100 kg-moles/hr 250 lb-moles/hr 115 kg-moles/hr

Temperature 59°F 15°C 79°F 26°C

Pressure 200 psia 14 kg/cm2 100 psia 7 kg/cm2

Table 31: Reaction Data (English)Reaction Rate Equation

Reaction rates are in lb-mole/ft3hr. Activation energies are in BTU/lb-mole.

Cl2 C3H6+ C3H5Cl HCl+→ Rate 3.36 1012× e27009.6–

RT----------------------⎝ ⎠

⎛ ⎞ CCl2( ) CC3H6

( )⋅=

Cl2 C3H6+ C3H6Cl2→ Rate 1.91 108× e6811.98–

RT----------------------⎝ ⎠

⎛ ⎞ CCl2( ) CC3H6

( )⋅=

Cl2 C3H5Cl+ C3H4Cl2 HCl+→ Rate 7.51 1015× e42300–RT

------------------⎝ ⎠⎛ ⎞ CCl2

( ) CC3H5Cl( )⋅=


✔ SOLUTION Build the flowsheet and enter the UOM, components, and thermody-namic data, as usual.

Step 1 Enter Reaction Data

➤ In the Reaction Data dialog box, enter a Reaction Set Name and click . The Reaction Definitions dialog box appears.

➤ There are three reactions. In the first row of the grid, enter a name for the first reaction.

➤ Click on the Reactants = Products text to open the Reaction Compo-nents dialog box.

In the first reaction, one mole of chlorine reacts with one mole of propy-lene to form one mole of allyl chloride and one mole of hydrogen chlo-ride, as shown below in Figure 57.

Figure 57: Stoichiometry for the

First Reaction

Table 32: Reaction Data (Metric)Reaction Rate Equation

Reaction rates are in kg-mole/m3hr. Activation energies are in kcal/kg-mole.

Cl2 C3H6+ C3H5Cl HCl+→ Rate 2.1 1011× e15005.4–

RT----------------------⎝ ⎠

⎛ ⎞ CCl2( ) CC3H6

( )⋅=

Cl2 C3H6+ C3H6Cl2→ Rate 1.19 107× e3784.45–

RT----------------------⎝ ⎠

⎛ ⎞ CCl2( ) CC3H6

( )⋅=

Cl2 C3H5Cl+ C3H4Cl2 HCl+→ Rate 4.69 1014× e23500.1–

RT----------------------⎝ ⎠

⎛ ⎞ CCl2( ) CC3H5Cl( )⋅=

Enter Data...

64 Propylene Chlorination Reactor

Enter the stoichometric data for the second and third reactions in a simi-lar manner until all three Reaction Definitions are blue in the Reaction Definitions dialog box.

The equations conform to the default Power Law Kinetic Rate Calcula-tion Method so you do not need to change this, just enter the data.

Figure 58: Reaction Definitions

➤ For the first reaction, click to enter kinetic data.

➤ Since this reaction takes place in the vapor phase, change the Default Phase to Vapor.

The completed dialog box is shown below.

Figure 59: Kinetic Data for the

First Reaction

K...


Enter the kinetic data for the second and third reactions in a similar way.

Step 2 Enter Unit Data

➤ In the Continuous Stirred Tank/Boiling Pot Reactor dialog box, select the Reaction Set you have just created.

➤ Enter the Fixed Temperature.

➤ Click and enter the Reactor Volume (Figure 60a).

➤ Click and enter 2.5 lbmoles/hr Cl2—1% CL2 flowrate [250 * 0.01 = 2.5] (Figure 60b).

Figure 60: (a) Reactor Volume

(b) Product Estimates

➤ Save the data and return to the main CST Reactor dialog box.

➤ Click and enter the Outlet Pressure.

The completed dialog box is shown in Figure 61.

Figure 61: Reactor

Specifications

➤ Run the simulation and view the results.

Reactor Data...

Product Estimates...

Pressure...


Approximately 94% of the chlorine and 62% of the propylene is con-verted into the products allyl chloride, 1,2-dichloropropane, 1,3-dichlo-ropropene and hydrogen chloride.

Figure 62: Reactor Summary English UOM

OPERATING CONDITIONS REACTOR TYPE ISOTHERMAL DUTY, MM BTU/HR -5.0728 TOTAL HEAT OF REACTION AT 77.00 F, MM BTU/HR -12.0313 VOLUME, FT3 10.0000 SPACE-TIME, HR AT OUTLET CONDITIONS 1.158E-04 SPACE-VELOCITY, /HR AT OUTLET CONDITIONS 8639.0894 INLET OUTLET ----------- ----------- FEED PRPL CL2 VAPOR PRODUCT PROD TEMPERATURE, F 52.41 800.00 PRESSURE, PSIA 100.0000 70.0000 REACTION DATA ------- RATES, LB-MOL/HR -------- FRACTION COMPONENT FEED CHANGE PRODUCT CONVERTED --------------- ----------- ---------- ---------- ---------- 1 CL2 249.9997 -235.2700 14.7297 0.9411 2 C3H6 219.9999 -135.5169 84.4830 0.6160 3 ACL 0.0000 14.8506 14.8506 4 12PR 0.0000 20.9131 20.9131 5 13PE 0.0000 99.7531 99.7531 6 HCL 0.0000 214.3569 214.3569 TOTAL 469.9996 -20.9131 449.0864

Metric UOM

OPERATING CONDITIONS REACTOR TYPE ISOTHERMAL DUTY, M*KCAL/HR -1.3273 TOTAL HEAT OF REACTION AT 25.00 C, M*KCAL/HR -3.0835 VOLUME, M3 0.3000 SPACE-TIME, HR AT OUTLET CONDITIONS 1.240E-04 SPACE-VELOCITY, /HR AT OUTLET CONDITIONS 8066.0654 INLET OUTLET ----------- ----------- FEED PRPL CL2 VAPOR PRODUCT PROD TEMPERATURE, C 11.24 425.00 PRESSURE, KG/CM2 7.0000 5.0000 REACTION DATA ------- RATES, KG-MOL/HR -------- FRACTION COMPONENT FEED CHANGE PRODUCT CONVERTED ---------------- --------- ---------- ---------- ----------- 1 CL2 115.0000 -108.4534 6.5466 0.9431 2 C3H6 100.0000 -62.4710 37.5290 0.6247 3 ACL 0.0000 6.7156 6.7156 4 12PR 0.0000 9.7729 9.7729 5 13PE 0.0000 45.9824 45.9824 6 HCL 0.0000 98.6805 98.6805 TOTAL 215.0000 -9.7729 205.2271


Appendix A - Keyword (.INP) Files - English UOM

Chiller Plant - Part 1TITLE DIMENSION ENGLISH, PRES=PSIG SEQUENCE SIMSCICOMPONENT DATA LIBID 1,N2/2,CO2/3,METHANE/4,ETHANE/5,PROPANE/6,IBUTANE/7,BUTANE/ & 8,IPENTANE/9,PENTANE PETRO 10,C6PLUS,,73.0001,210 PHASE VL=10THERMODYNAMIC DATA METHOD SYSTEM=PR, TRANSPORT=PETR, SET=PR01, DEFAULTSTREAM DATA PROPERTY STREAM=INLET_GAS, TEMPERATURE=120, PRESSURE=190.3, PHASE=M, & RATE(GV)=1.66667E6, COMPOSITION(M)=1,1/2,1.6/3,72.5/4,11.5/ & 5,6.75/6,1.25/7,3/8,0.55/9,1.1/10,0.75UNIT OPERATIONS FLASH UID=D-1 FEED INLET_GAS PRODUCT V=2, L=3 ISO TEMPERATURE=84.999, PRESSURE=203 PUMP UID=P-1 FEED 3 PRODUCT M=17 OPERATION EFF=65, PRESSURE=550 COMPRESSOR UID=C-1 FEED 2 PRODUCT V=4 OPERATION CALCULATION=ASME, PRES=600, EFF=72 HX UID=HX-1 HOT FEED=4, M=5, DP=5 UTILITY AIR, TIN=80.001, TEMPERATURE=100 CONFIGURE COUNTER OPER HTEMP=110 FLASH UID=D-2 FEED 5 PRODUCT V=6, L=7 ADIABATICEND

Chiller Plant - Part 2TITLE DIMENSION ENGLISH, PRES=PSIG SEQUENCE SIMSCICOMPONENT DATA LIBID 1,N2/2,CO2/3,METHANE/4,ETHANE/5,PROPANE/6,IBUTANE/7,BUTANE/ & 8,IPENTANE/9,PENTANE PETRO 10,C6PLUS,,73.0001,210 PHASE VL=10THERMODYNAMIC DATA METHOD SYSTEM=PR, TRANSPORT=PETR, SET=PR01, DEFAULTSTREAM DATA PROPERTY STREAM=INLET_GAS, TEMPERATURE=120, PRESSURE=190.3, PHASE=M, & RATE(GV)=1.66667E6, COMPOSITION(M)=1,1/2,1.6/3,72.5/4,11.5/ & 5,6.75/6,1.25/7,3/8,0.55/9,1.1/10,0.75UNIT OPERATIONS FLASH UID=D-1 FEED INLET_GAS PRODUCT V=2, L=3 ISO TEMPERATURE=84.999, PRESSURE=203 PUMP UID=P-1 FEED 3 PRODUCT M=17 OPERATION EFF=65, PRESSURE=550 COMPRESSOR UID=C-1 FEED 2 PRODUCT V=4 OPERATION CALCULATION=ASME, PRES=600, EFF=72 HX UID=HX-1 HOT FEED=4, M=5, DP=5 UTILITY AIR, TIN=80.001, TEMPERATURE=100 CONFIGURE COUNTER


OPER HTEMP=110 FLASH UID=D-2 FEED 5 PRODUCT V=6, L=7 ADIABATIC HX UID=HX-2 HOT FEED=6, M=8, DP=5 COLD FEED=10, M=12, DP=5 CONFIGURE COUNTER OPER HICO=10 HX UID=HX-3 HOT FEED=8, M=9, DP=5 UTILITY REFRIGERANT, COMPONENT=5, TSAT=-22 CONFIGURE COUNTER OPER HTEMP=-13 FLASH UID=D-3 FEED 9 PRODUCT V=10, L=11 ADIABATIC VALVE UID=V-1 FEED 11 PRODUCT M=13 OPERATION PRESSURE=245END

Chiller Plant - Part 3TITLE DIMENSION ENGLISH, PRES=PSIG SEQUENCE SIMSCICOMPONENT DATA LIBID 1,N2/2,CO2/3,METHANE/4,ETHANE/5,PROPANE/6,IBUTANE/7,BUTANE/ & 8,IPENTANE/9,PENTANE PETRO 10,C6PLUS,,73.0001,210 PHASE VL=10THERMODYNAMIC DATA METHOD SYSTEM=PR, TRANSPORT=PETR, SET=PR01, DEFAULTSTREAM DATA PROPERTY STREAM=INLET_GAS, TEMPERATURE=120, PRESSURE=190.3, PHASE=M, & RATE(GV)=1.66667E6, COMPOSITION(M)=1,1/2,1.6/3,72.5/4,11.5/ & 5,6.75/6,1.25/7,3/8,0.55/9,1.1/10,0.75 PROPERTY STREAM=50, PRESSURE=11.5, PHASE=L, RATE(WT)=36896.4, & COMPOSITION(M)=4,2.5/5,97/6,0.5UNIT OPERATIONS FLASH UID=D-1 FEED INLET_GAS PRODUCT V=2, L=3 ISO TEMPERATURE=84.999, PRESSURE=203 PUMP UID=P-1 FEED 3 PRODUCT M=17 OPERATION EFF=65, PRESSURE=550 COMPRESSOR UID=C-1 FEED 2 PRODUCT V=4 OPERATION CALCULATION=ASME, PRES=600, EFF=72 HX UID=HX-1 HOT FEED=4, M=5, DP=5 UTILITY AIR, TIN=80.001, TEMPERATURE=100 CONFIGURE COUNTER OPER HTEMP=110 FLASH UID=D-2 FEED 5 PRODUCT V=6, L=7 ADIABATIC HX UID=HX-3 HOT FEED=8, M=9, DP=5 COLD FEED=50, M=51 CONFIGURE COUNTER OPER CLFRAC=0 CONTROLLER UID=CN1 SPEC STREAM=9, TEMPERATURE(F), VALUE=-15 VARY STREAM=50, RATE CPARAMETER IPRINT, NOSTOP FLASH UID=D-3 FEED 9 PRODUCT V=10, L=11 ADIABATIC HX UID=HX-2 HOT FEED=6, M=8, DP=5

70 Appendix A - Keyword (.INP) Files - English UOM

COLD FEED=10, M=12, DP=5 CONFIGURE COUNTER OPER HICO=10 VALVE UID=V-1 FEED 11 PRODUCT M=13 OPERATION PRESSURE=245END

Chiller Plant -Part 4TITLE DIMENSION ENGLISH, PRES=PSIG SEQUENCE SIMSCICOMPONENT DATA LIBID 1,N2/2,CO2/3,METHANE/4,ETHANE/5,PROPANE/6,IBUTANE/7,BUTANE/ & 8,IPENTANE/9,PENTANE PETRO 10,C6PLUS,,73.0001,210 PHASE VL=10THERMODYNAMIC DATA METHOD SYSTEM=PR, TRANSPORT=PETR, SET=PR01, DEFAULTSTREAM DATA PROPERTY STREAM=INLET_GAS, TEMPERATURE=120, PRESSURE=190.3, PHASE=M, & RATE(GV)=1.66667E6, COMPOSITION(M)=1,1/2,1.6/3,72.5/4,11.5/ & 5,6.75/6,1.25/7,3/8,0.55/9,1.1/10,0.75 PROPERTY STREAM=50, PRESSURE=11.5, PHASE=L, RATE(WT)=36000, & COMPOSITION(M)=4,2.5/5,97/6,0.5UNIT OPERATIONS FLASH UID=D-1 FEED INLET_GAS PRODUCT V=2, L=3 ISO TEMPERATURE=84.999, PRESSURE=203 COMPRESSOR UID=C-1 FEED 2 PRODUCT V=4 OPERATION CALCULATION=ASME, PRES=600, EFF=72 HX UID=HX-1 HOT FEED=4, M=5, DP=5 UTILITY AIR, TIN=80.001, TEMPERATURE=100 CONFIGURE COUNTER OPER HTEMP=110 FLASH UID=D-2 FEED 5 PRODUCT V=6, L=7 ADIABATIC HX UID=HX-3 HOT FEED=8, M=9, DP=5 COLD FEED=50, M=51 CONFIGURE COUNTER OPER CLFRAC=0 CONTROLLER UID=CN1 SPEC STREAM=9, TEMPERATURE(F), VALUE=-15 VARY STREAM=50, RATE CPARAMETER IPRINT, NOSTOP FLASH UID=D-3 FEED 9 PRODUCT V=10, L=11 ADIABATIC HX UID=HX-2 HOT FEED=6, M=8, DP=5 COLD FEED=10, M=12, DP=5 CONFIGURE COUNTER OPER HICO=10 VALVE UID=V-1 FEED 11 PRODUCT M=13 OPERATION PRESSURE=245 COLUMN UID=T-1 PARAMETER TRAY=13,IO FEED 13,1 PRODUCT OVHD(M)=14, BTMS(M)=15, SUPERSEDE=ON DUTY 1,13 PSPEC PTOP=200, DPCOLUMN=2.5 PRINT PROPTABLE=PART ESTIMATE MODEL=CONVENTIONAL, RRATIO=3 SPEC STREAM=15, TVP(PSIG), VALUE=235 DEFINE PRODUCT(LBM/H)=14 AS STREAM=13, RATE(LBM/H), COMP=1,3, & WET VARY DUTY=1 REBOILER TYPE=KETTLE


COMPRESSOR UID=C-2 FEED 14 PRODUCT V=16 OPERATION CALCULATION=ASME, PRES=600, EFF=73 PUMP UID=P-1 FEED 3,15 PRODUCT M=17 OPERATION EFF=65, PRESSURE=550 MIXER UID=M-2 FEED 16,12 PRODUCT M=18 MIXER UID=M-1 FEED 7,17 PRODUCT M=19END

Chiller Plant - Part 5TITLE DIME ENGLISH, PRES=PSIG, LIQV=GAL PRINT STREAMS=COMPONENTCOMP DATA LIBID 1,N2/2,CO2/3,C1/4,C2/5,C3/6,IC4/7,NC4/8,IC5/9,NC5 PETRO 10,C6 PLUS,,73, 210THERMO DATA METHODS SYSTEM=PR, TRANSPORT=PETROSTREAM DATA PROP STRM=17, TEMP=98.2, PRES=550, RATE=598.20,* COMP=.009/2.4352/2.1162/141.0459/192.6925/45.3291/115.2106/22.6544/* 45.7673/31.0565 PROP STRM=60, TEMP=100, PRES=600, RATE=666.9,* COMP=.1/1.8/4/125/220/78/150/10/48/30 NAME 17,NGL LIQUIDS/ 60, ROYAL LIQUIDS OUTPUT FORMAT=GASUNIT OPS VALVE UID=V-2, NAME=LET DOWN FEED 17,60 PROD M=20 OPERATION PRESSURE=425 SHORT UID=T-2S, NAME=DEETHANIZER FEED 20 PROD STRM=21, PRES=410, RATE=275, PHASE=V PROD STRM=22, SPEC STRM=21, COMP=5, FRAC, VALUE=.02 SPEC STRM=22, COMP=4, RATE, DIVIDE, STRM=22, COMP=5, RATE, VALUE=.025 CONDENSER TYPE=PART EVALUATE MODEL=CONV,MMMIN=2, KEYL=4,KEYH=5 VALVE UID=V-3, NAME=LET DOWN FEED 22 PROD M=23 OPERATION PRESSURE=260 SHORT UID=T-3S, NAME=DEPROPANIZER FEED 23 PROD STRM=24, PHASE=L, PRES=240, RATE=400 CONDENSER TYPE=BUBB PROD STRM=25, SPEC STRM=24, COMP=6,7, FRAC, VALUE=.02 SPEC STRM=25, COMP=5, FRAC, VALUE=.02 EVALUATE MODEL=CONV, MMMIN=2, KEYL=5, KEYH=6 VALVE UID=V-4, NAME=LETDOWN FEED 25 PROD M=26 OPERATION PRESSURE=130 SHORT UID=T-4S, NAME=DEBUTANIZER FEED 26 PROD STRM=27, PHASE=L, PRES=100, RATE=450 PROD STRM=28, CONDENSER TYPE=BUBB EVALUATE MMMIN=2, MODEL=CONV, KEYL=7, KEYH=8 SPEC STRM=27, COMP=8, FRAC(V), VALUE=.0025 SPEC STRM=28, COMP=7, FRAC(V), VALUE=.01 CALCULATOR UID=CAL1, NAME=RVP CALC RESULT 1,STRM 28 RVP DEFINE P(1) AS STRM=28, RVP PROCEDURE R(1)=P(1) RETURNEND


Chiller Plant - Part 6TITLE PRINT STREAM=COMPONENT DIMENSION ENGLISH, PRES=PSIG, LIQVOL=GAL SEQUENCE SIMSCICOMPONENT DATA LIBID 1,N2/2,CO2/3,C1/4,C2/5,C3/6,IC4/7,NC4/8,IC5/9,NC5 PETRO 10,C6PLUS,,73.0001,210THERMODYNAMIC DATA METHOD SYSTEM=PR, TRANSPORT=PETR, SET=PR01STREAM DATA PROPERTY STREAM=17, TEMPERATURE=98.2, PRESSURE=550, PHASE=M, & COMPOSITION(M,LBM/H)=1,0.009/2,2.4352/3,2.1162/4,141.046/ & 5,192.693/6,45.3291/7,115.211/8,22.6544/9,45.7673/10,31.0565 PROPERTY STREAM=60, TEMPERATURE=100, PRESSURE=600, PHASE=M, & COMPOSITION(M,LBM/H)=1,0.1/2,1.8/3,4/4,125/5,220/6,78/7,150/ & 8,10/9,48/10,30 NAME 17,NGL LIQUIDS/60,ROYAL LIQUIDSUNIT OPERATIONS COLUMN UID=T-2, NAME=Deethanizer PARAMETER TRAY=24,IO=15 FEED 20,13 PRODUCT OVHD(M)=S21,271.74, BTMS(M)=S22, SUPERSEDE=ON CONDENSER TYPE=PART, PRESSURE=410 DUTY 1,1,-2.61699/2,24,8.81295 PSPEC PTOP=415, DPCOLUMN=5 PRINT PROPTABLE=PART ESTIMATE MODEL=CONVENTIONAL, RRATIO=2.674 SPEC STREAM=S21,FRACTION, COMP=5,WET, VALUE=0.02 SPEC STREAM=S22, RATE(LBM/H), COMP=4,WET, DIVIDE, STREAM=S22, & RATE(LBM/H), COMP=5,WET, VALUE=0.025 VARY DUTY=1,2 TSIZE SECTION(1)=2,23,VALVE, DMIN=15 REBOILER TYPE=KETTLE COLUMN UID=T-3, NAME=Depropanizer PARAMETER TRAY=23,IO=15 FEED S23,11 PRODUCT OVHD(M)=S24,414.1, BTMS(M)=S25, SUPERSEDE=ON CONDENSER TYPE=TFIX, PRESSURE=240, TEMPERATURE=110 DUTY 1,1,-8.89596/2,23,7.34597 PSPEC PTOP=245, DPCOLUMN=5 PRINT PROPTABLE=PART ESTIMATE MODEL=CONVENTIONAL, RRATIO=2.943 SPEC STREAM=S24,FRACTION, COMP=6,7,WET, VALUE=0.02 SPEC STREAM=S25,FRACTION, COMP=5,WET, VALUE=0.02 VARY DUTY=1,2 TSIZE SECTION(1)=2,22,VALVE, DMIN=15 REBOILER TYPE=KETTLE COLUMN UID=T-4, NAME=Debutanizer PARAMETER TRAY=30,IO=15 FEED S26,16 PRODUCT OVHD(M)=S27,390, BTMS(M)=S28, SUPERSEDE=ON CONDENSER TYPE=TFIX, PRESSURE=100, TEMPERATURE=110, TEST=110 DUTY 1,1,-8.56796/2,30,7.04198 PSPEC PTOP=105, DPCOLUMN=5 PRINT PROPTABLE=PART ESTIMATE MODEL=CONVENTIONAL, RRATIO=1.834, CTEMP=110 SPEC STREAM=S27,FRACTION(LV), COMP=8,WET, VALUE=0.0025 SPEC STREAM=S28,FRACTION(LV), COMP=7,WET, VALUE=0.01 VARY DUTY=1,2 TSIZE SECTION(1)=2,29,VALVE, DMIN=15 REBOILER TYPE=KETTLE VALVE UID=V-2, NAME=LET DOWN FEED 17,60 PRODUCT M=20 OPERATION PRESSURE=425 VALVE UID=V-3 FEED S22 PRODUCT M=S23 OPERATION PRESSURE=260 VALVE UID=V-4 FEED S25 PRODUCT M=S26 OPERATION PRESSURE=130END


Gas Cooling

Process with Recycle StreamTITLE PRINT INPUT=NONE DIMENSION ENGLISH, XDENSITY=SPGR SEQUENCE PROCESSCOMPONENT DATA LIBID 1,CO2/2,C1/3,C2/4,C3/5,IC4/6,NC4/7,IC5/8,NC5/9,NC6THERMODYNAMIC DATA METHOD SYSTEM=PR, SET=PR01STREAM DATA PROPERTY STREAM=1, TEMPERATURE=150, PRESSURE=3600, PHASE=M, & RATE(M)=1000, COMPOSITION(M)=1,1.39/2,85.92/3,7.73/4,2.45/ & 5,0.36/6,0.56/7,0.21/8,0.26/9,1.12UNIT OPERATIONS VALVE UID=V1 FEED 1 PRODUCT M=2 OPERATION DP=1600 HX UID=E1 HOT FEED=2, M=3, DP=5 COLD FEED=6, M=8, DP=5 CONFIGURE COUNTER OPER HICO=15 VALVE UID=V2 FEED 3 PRODUCT M=4 OPERATION DP=900 HX UID=E2 HOT FEED=4, M=5X, DP=5 OPER HTEMP=-20 FLASH UID=F1 FEED 5X PRODUCT V=6, L=7 ADIABATIC DP=0END

Process with Broken RecycleTITLE PRINT INPUT=NONE DIMENSION ENGLISH, XDENSITY=SPGR SEQUENCE PROCESSCOMPONENT DATA LIBID 1,CO2/2,C1/3,C2/4,C3/5,IC4/6,NC4/7,IC5/8,NC5/9,NC6THERMODYNAMIC DATA METHOD SYSTEM=PR, SET=PR01STREAM DATA PROPERTY STREAM=1, TEMPERATURE=150, PRESSURE=3600, PHASE=M, & RATE(M)=1000, COMPOSITION(M)=1,1.39/2,85.92/3,7.73/4,2.45/ & 5,0.36/6,0.56/7,0.21/8,0.26/9,1.12 PROPERTY STREAM=5, TEMPERATURE=-20, PRESSURE=1090, REFSTREAM=1UNIT OPERATIONS VALVE UID=V1 FEED 1 PRODUCT M=2 OPERATION DP=1600 FLASH UID=F1 FEED 5 PRODUCT V=6, L=7 ADIABATIC DP=0 HX UID=E1 HOT FEED=2, M=3, DP=5 COLD FEED=6, M=8, DP=5 CONFIGURE COUNTER OPER HICO=15 VALVE UID=V2 FEED 3 PRODUCT M=4 OPERATION DP=900 HX UID=E2 HOT FEED=4, M=5X, DP=5 OPER HTEMP=-20END


MEK/Toluene PreheatTITLE SEQUENCE PROCESSCOMPONENT DATA LIBID 1,MEK/2,TOLUENE/3,WATERTHERMODYNAMIC DATA METHOD SYSTEM=NRTL, ENTHALPY(V)=SRKM, DENSITY(V)=SRKM, SET=NRTL01, & DEFAULTSTREAM DATA PROPERTY STREAM=FEED, TEMPERATURE=190, PRESSURE=20, PHASE=M, & RATE(M)=100, COMPOSITION(M)=1,19/2,80/3,1UNIT OPERATIONS FLASH UID=FD FEED FEED PRODUCT V=VAPOR, L=S1 TPSPEC DP=1 SPEC STREAM=VAPOR, RATE(LBM/H),TOTAL,WET, DIVIDE, REFFEED, & RATE(LBM/H),WET, VALUE=0.4 HX UID=HX COLD FEED=S1, L=PROD, DP=1 DEFINE DUTY(BTU/HR) AS 1, MINUS, FLASH=FD, DUTY(BTU/HR)END

Hydrocarbon-Water Phase SeparationTITLE DIMENSION ENGLISH, LIQVOL=BBL SEQUENCE SIMSCICOMPONENT DATA LIBID 1,WATER/2,CO2/3,N2/4,C1/5,C2/6,C3/7,IC4/8,NC4/9,IC5/10,NC5 PETRO 11,CUT11,91,63.9999,180/12,CUT12,100,61,210/ & 13,CUT13,120,55,280/14,CUT14,150,47.9999,370/ & 15,CUT15,200,40.0001,495THERMODYNAMIC DATA METHOD SYSTEM=SRK, SET=SRK1 WATER SOLUBILITY=SIMSCI METHOD SYSTEM=SRK, SET=SRK2 WATER SOLUBILITY=KEROSENE METHOD SYSTEM=SRK, SET=SRK3 WATER SOLUBILITY=EOS METHOD SYSTEM(VLLE)=SRKK, SET=SRKKSTREAM DATA PROPERTY STREAM=CRUDE, TEMPERATURE=150, PRESSURE=1000, PHASE=M, & COMPOSITION(M,LBM/H)=1,3000/2,35/3,30/4,890/5,300/6,520/ & 7,105/8,283/9,100/10,133/11,165/12,303/13,560/14,930/15,300 PROPERTY STREAM=CRUDE_R1, REFSTREAM=CRUDE PROPERTY STREAM=CRUDE_R2, REFSTREAM=CRUDE PROPERTY STREAM=CRUDE_R3, REFSTREAM=CRUDEUNIT OPERATIONS FLASH UID=DCNT-SIMSCI, KPRINT FEED CRUDE PRODUCT V=1V, L=1L, W=1W ISO TEMPERATURE=300, PRESSURE=300 METHOD SET=SRK1 FLASH UID=DECANT-EOS FEED CRUDE_R1 PRODUCT V=3V, L=3L, W=3W ISO TEMPERATURE=300, PRESSURE=300 METHOD SET=SRK3 FLASH UID=DECANT-KERO FEED CRUDE_R2 PRODUCT V=2V, L=2L, W=2W ISO TEMPERATURE=300, PRESSURE=300 METHOD SET=SRK2 FLASH UID=RIG-SRKKD, KPRINT FEED CRUDE_R3 PRODUCT V=4V, L=4L, W=4W ISO TEMPERATURE=300, PRESSURE=300 METHOD SET=SRKKEND


Naphtha Assay - Part 1TITLE DIMENSION ENGLISH, PRES=ATM SEQUENCE SIMSCICOMPONENT DATA LIBID 1,IBUTANE/2,BUTANE/3,IPENTANE/4,PENTANE ASSAY TBPIP=3 CUTPOINTS TBPCUTS=80.0006,460,21/1200,8/1600,4THERMODYNAMIC DATA METHOD SYSTEM=SRK, SET=SRK01, DEFAULTSTREAM DATA PROPERTY STREAM=NAPHTHA_FEED, TEMPERATURE=100, PRESSURE=1, PHASE=M, & RATE(WT)=1000, ASSAY=LV D86 STREAM=NAPHTHA_FEED, DATA=3,90/5,125/10,195/30,250/50,280/ & 70,310/90,390/95,418/98,430, TEMP=F API STREAM=NAPHTHA_FEED, AVERAGE=54.2 LIGHTEND STREAM=NAPHTHA_FEED, COMPOSITION(M)=1,0.7/2,2.15/3,0.86/ & 4,3.58, PERCENT(LV)=5, NORMALIZEUNIT OPERATIONS$ *** NO UNITS ***END

Naphtha Assay - Part 2TITLE DIMENSION ENGLISH, PRES=ATM SEQUENCE SIMSCICOMPONENT DATA LIBID 1,IBUTANE/2,BUTANE/3,IPENTANE/4,PENTANE ASSAY TBPIP=3 CUTPOINTS TBPCUTS=80.0006,460,21/1200,8/1600,4THERMODYNAMIC DATA METHOD SYSTEM=SRK, SET=SRK01, DEFAULTSTREAM DATA PROPERTY STREAM=NAPHTHA_FEED, TEMPERATURE=100, PRESSURE=1, PHASE=M, & RATE(WT)=1000, ASSAY=LV D86 STREAM=NAPHTHA_FEED, DATA=3,90/5,125/10,195/30,250/50,280/ & 70,310/90,390/95,418/98,430, TEMP=F API STREAM=NAPHTHA_FEED, AVERAGE=54.2 LIGHTEND STREAM=NAPHTHA_FEED, COMPOSITION(M)=1,0.7/2,2.15/3,0.86/ & 4,3.58, PERCENT(LV)=5, NORMALIZEUNIT OPERATIONS FLASH UID=F1 FEED NAPHTHA_FEED PRODUCT V=F1VAPOR, L=F1LIQUID TPSPEC PRESSURE=0.8 SPEC STREAM=F1VAPOR, RATE(LBM/H),TOTAL,WET, DIVIDE, & STREAM=NAPHTHA_FEED, RATE(LBM/H),TOTAL,WET, & VALUE=0.8 FLASH UID=F2 FEED F1VAPOR PRODUCT V=F2VAPOR, L=F2LIQUID ISO DP=0.1 DEFINE TEMP(F) AS STREAM=F1VAPOR, TEMPERATURE(F), MINUS,18END

Naphtha Assay - Part 3TITLE DIMENSION ENGLISH, PRES=ATM SEQUENCE SIMSCICOMPONENT DATA LIBID 1,IBUTANE/2,BUTANE/3,IPENTANE/4,PENTANE ASSAY TBPIP=3 CUTPOINTS TBPCUTS=80.0006,460,21/1200,8/1600,4THERMODYNAMIC DATA METHOD SYSTEM=SRK, SET=SRK01, DEFAULTSTREAM DATA PROPERTY STREAM=NAPHTHA_FEED, TEMPERATURE=100, PRESSURE=1, PHASE=M, & RATE(WT)=1000, ASSAY=LV D86 STREAM=NAPHTHA_FEED, DATA=3,90/5,125/10,195/30,250/50,280/ & 70,310/90,390/95,418/98,430, TEMP=F API STREAM=NAPHTHA_FEED, AVERAGE=54.2 LIGHTEND STREAM=NAPHTHA_FEED, COMPOSITION(M)=1,0.7/2,2.15/3,0.86/ & 4,3.58, PERCENT(LV)=5, NORMALIZE


UNIT OPERATIONS FLASH UID=F1 FEED NAPHTHA_FEED PRODUCT V=F1VAPOR, L=F1LIQUID TPSPEC PRESSURE=0.8 SPEC STREAM=F1VAPOR, RATE(LBM/H),TOTAL,WET, DIVIDE, & STREAM=NAPHTHA_FEED, RATE(LBM/H),TOTAL,WET, & VALUE=0.8 FLASH UID=F2 FEED F1VAPOR PRODUCT V=F2VAPOR, L=F2LIQUID ISO DP=0.1 DEFINE TEMP(F) AS STREAM=F1VAPOR, TEMPERATURE(F), MINUS,18CASESTUDY OLDCASE=BASECASE, NEWCASE=CS1 PARAMETER ID=F1SPLIT, FLASH=F1, SPEC(1),STEP(ACT)=-0.1, CYCLES =1,5 RESULT ID=F2DUTY, FLASH=F2, DUTY(BTU/HR)END

Phase EnvelopeTITLE SEQUENCE PROCESSCOMPONENT DATA LIBID 1,C1/2,C2/3,C3/4,IC4/5,NC4/6,IC5THERMODYNAMIC DATA METHOD SYSTEM=SRK, SET=SRK01, DEFAULTSTREAM DATA PROPERTY STREAM=S1, TEMPERATURE=150, PRESSURE=2500, PHASE=M, & RATE(M)=100, COMPOSITION(M)=1,82/2,7/3,4/4,2/5,2/6,3UNIT OPERATIONS PHASE UID=PH1 EVAL STREAM=S1, LFRAC=0, IPLOT=OFF, CPLOT=1 EVAL STREAM=S1, LFRAC=0.05,IPLOT=OFF, CPLOT=2 EVAL STREAM=S1, LFRAC=0.1,IPLOT=OFF, CPLOT=3 EVAL STREAM=S1, LFRAC=0.15,IPLOT=OFF, CPLOT=4 EVAL STREAM=S1, LFRAC=1,IPLOT=OFF, CPLOT=5END

Compressor CurvesTITLE SEQUENCE SIMSCICOMPONENT DATA LIBID 1,C2/2,C3/3,IC4/4,NC4THERMODYNAMIC DATA METHOD SYSTEM=SRK, SET=SRK01, DEFAULTSTREAM DATA PROPERTY STREAM=S1, TEMPERATURE=15.499, PRESSURE=315, PHASE=M, & RATE(M)=16500, COMPOSITION(M)=1,1.04/2,96.94/3,1.68/4,0.34UNIT OPERATIONS VALVE UID=V1 FEED S1 PRODUCT M=S2 OPERATION PRESSURE=87 HX UID=E1 HOT FEED=S2, V=S4, L=S5, DP=4.4 OPER DUTY=2 HX UID=E2 HOT FEED=S5, M=S6, DP=8.8 OPER HDTADEW=1E-15 MIXER UID=M1 FEED S4,S6 PRODUCT M=S7 OPERATION PRESSURE=65 COMPRESSOR UID=C1 FEED S7 PRODUCT V=S8 HEAD ACTUAL=900001,38000/1E6,37000/1.24E6,35299.9/ & 1.36E6,33100.1/1.43E6,27250 EFFICIENCY ADIA=900001,69/1E6,71/1.24E6,72/1.36E6,73/1.43E6,71 OPERATION CALCULATION=ASMEEND


DebutanizerTITLE DIMENSION ENGLISH, XDENSITY=SPGR SEQUENCE SIMSCICOMPONENT DATA LIBID 1,H2/2,H2S/3,C1/4,C2/5,C3/6,IC4/7,NC4/8,IC5/9,NC5THERMODYNAMIC DATA METHOD SYSTEM=SRK, SET=SRK01, DEFAULTSTREAM DATA PROPERTY STREAM=LPG, TEMPERATURE=104, PRESSURE=270, PHASE=M, & RATE(LV)=400, COMPOSITION(M)=1,0.3/2,0.2/3,0.7/4,5.5/5,28.5/ & 6,11.7/7,49/8,4.1 PROPERTY STREAM=NAPHTHA, TEMPERATURE=104, PRESSURE=270, PHASE=M, & RATE(LV)=3200, ASSAY=LV D86 STREAM=NAPHTHA, DATA=0,104/5,144/10,158/30,196/50,228/70,248/ & 90,284/95,311/100,329, TEMP=F SPGR STREAM=NAPHTHA, AVERAGE=0.75 LIGHTEND STREAM=NAPHTHA, COMPOSITION(LV)=5,0.07/6,0.21/7,0.42/ & 8,3.24/9,6.06, PERCENT(LV)=10, NORMALIZEUNIT OPERATIONS FLASH UID=F1 FEED LPG,NAPHTHA PRODUCT L=CFEED ISO TEMPERATURE=338, PRESSURE=270 COLUMN UID=DEBU PARAMETER TRAY=32,IO FEED CFEED,15 PRODUCT OVHD(M)=OVHD, BTMS(M)=BTMS, SUPERSEDE=ON CONDENSER TYPE=BUBB, PRESSURE=185 DUTY 1,1/2,32 PSPEC PTOP=190, DPCOLUMN=4.3 PRINT PROPTABLE=PART ESTIMATE MODEL=CONVENTIONAL, RRATIO=3 SPEC STREAM=OVHD, RATE(LBM/H), COMP=6,7,WET, DIVIDE, & STREAM=CFEED, RATE(LBM/H), COMP=6,7,WET, VALUE=0.995 SPEC STREAM=OVHD, RATE(LBM/H), COMP=8,9,WET, DIVIDE, & STREAM=CFEED, RATE(LBM/H), COMP=8,9,WET, VALUE=0.005 DEFINE PRODUCT(LBM/H)=OVHD AS STREAM=CFEED, RATE(LBM/H), & COMP=1,7,WET VARY DUTY=1,2 REBOILER TYPE=KETTLEEND


Part ATITLE DESCRIPTION PRINT INPUT=NONE DIMENSION ENGLISH, PRES=PSIG SEQUENCE SIMSCICOMPONENT DATA LIBID 1,NC4/2,IC5/3,NC5/4,NC6/5,NC7/6,NC8THERMODYNAMIC DATA METHOD SYSTEM=SRK, TRANSPORT=PETR, SET=SRK01, DEFAULTSTREAM DATA PROPERTY STREAM=FD1, TEMPERATURE=70, PRESSURE=180, PHASE=M, & RATE(WT)=550000, COMPOSITION(M)=1,15/2,14/3,16/4,22/5,13/ & 6,20 PROPERTY STREAM=BT1, TEMPERATURE=220, PRESSURE=120, PHASE=M, & RATE(WT)=500000, COMPOSITION(M)=1,4/2,15/3,16/4,25/5,15/6,25UNIT OPERATIONS HXRIG UID=E1 TYPE TEMA=AES, ORIENTATION=HORI, FLOW=COUN, AREA=2295 TUBES FEED=FD1, M=FD2, BWG=14, NUMBER=600, PATTERN=60, & PITCH=1.25, FOUL=0 SHELL FEED=BT1, M=BT2, ID=36 BAFFLE CUT=0.3, SPACING=24, INSPACING=24, OUTSPACING=24 SNOZZLE TYPE=CONV, ID=8,8 TNOZZLE ID=8,8 PRINT EXTENDED OPERATION STEMP=162END


Part BTITLE PRINT INPUT=NONE DIMENSION ENGLISH, PRES=PSIG SEQUENCE SIMSCICOMPONENT DATA LIBID 1,NC4/2,IC5/3,NC5/4,NC6/5,NC7/6,NC8THERMODYNAMIC DATA METHOD SYSTEM=SRK, TRANSPORT=PETR, SET=SRK01, DEFAULTSTREAM DATA PROPERTY STREAM=FD1, TEMPERATURE=70, PRESSURE=180, PHASE=M, & RATE(WT)=600000, COMPOSITION(M)=1,15/2,14/3,16/4,22/5,13/ & 6,20 PROPERTY STREAM=BT1, TEMPERATURE=220, PRESSURE=120, PHASE=M, & RATE(WT)=650000, COMPOSITION(M)=1,4/2,15/3,16/4,25/5,15/6,25UNIT OPERATIONS HXRIG UID=E1 TYPE TEMA=AES, ORIENTATION=HORI, FLOW=COUN, AREA=2295 TUBES FEED=FD1, M=FD2, BWG=14, NUMBER=600, PATTERN=60, & PITCH=1.25, FOUL=0 SHELL FEED=BT1, M=BT2, FOUL=0.00393, ID=36 BAFFLE CUT=0.3, SPACING=24, INSPACING=24, OUTSPACING=24 SNOZZLE TYPE=CONV, ID=8,8 TNOZZLE ID=8,8 PRINT EXTENDEDEND

Two Stage CompressorTITLE SEQUENCE SIMSCICOMPONENT DATA LIBID 1,N2/2,CO2/3,C1/4,C2/5,C3/6,IC4/7,NC4/8,IC5/9,NC5/10,NC6/ & 11,NC9THERMODYNAMIC DATA METHOD SYSTEM=PR, DENSITY(L)=COST, SET=PR01, DEFAULTSTREAM DATA PROPERTY STREAM=S1, TEMPERATURE=100, PRESSURE=70, PHASE=M, & COMPOSITION(M,LBM/H)=1,400/2,4230/3,32000/4,20000/5,16000/ & 6,1700/7,6200/8,2100/9,3600/10,3400/11,7000UNIT OPERATIONS FLASH UID=D-1 FEED S1,S7 PRODUCT V=S2, L=S3 ADIABATIC COMPRESSOR UID=C-1 FEED S2 PRODUCT V=S4 OPERATION CALCULATION=ASME, PRES=170, EFF=74 HX UID=HX-1 HOT FEED=S4, M=S5, DP=5 OPER HTEMP=135 FLASH UID=D-2 FEED S5,S11 PRODUCT V=S6, L=S7 ADIABATIC COMPRESSOR UID=C-2 FEED S6 PRODUCT V=S8 OPERATION CALCULATION=ASME, PRES=380, EFF=72 HX UID=HX-2 HOT FEED=S8, M=S9, DP=5 OPER HTEMP=135 FLASH UID=D-3 FEED S9 PRODUCT V=S10, L=S11 ADIABATICEND


Propylene Chlorination ReactorTITLE DIMENSION ENGLISH, STDTEMP=60.0008, STDPRES=14.6959 SEQUENCE SIMSCI CALCULATION RVPBASIS=APIN, TVP=100COMPONENT DATA LIBID 1,CL2/2,C3H6/3,C3H5CL/4,HCL/5,C3H6CL2/6,C3H4CL2THERMODYNAMIC DATA METHOD SYSTEM=SRK, DENSITY(L)=COST, SET=SRK01, DEFAULTSTREAM DATA PROPERTY STREAM=S1, TEMPERATURE=59, PRESSURE=200, PHASE=M, & RATE(M)=220, COMPOSITION(M)=2,1 PROPERTY STREAM=S2, TEMPERATURE=79, PRESSURE=100, PHASE=M, & RATE(M)=250, COMPOSITION(M)=1,1RXDATA RXSET ID=1 REACTION ID=1 STOICHIOMETRY 1,-1/2,-1/3,1/4,1 KINETICS PEXP=3.36E12, ACTIVATION=27.01, TEXPONENT=0 KPHASE DEFAULT=V REACTION ID=2 STOICHIOMETRY 1,-1/2,-1/5,1 KINETICS PEXP=1.91E8, ACTIVATION=6.812, TEXPONENT=0 KPHASE DEFAULT=V REACTION ID=3 STOICHIOMETRY 1,-1/3,-1/4,1/6,1 KINETICS PEXP=7.51E15, ACTIVATION=42.3, TEXPONENT=0 KPHASE DEFAULT=VUNIT OPERATIONS CSTR UID=R1 FEED S1,S2 PRODUCT M=S3 OPERATION VOLUME=10, PRESSURE=70, TEMPERATURE=800 FESTIMATE 1,2.5 RXSTOIC RXSET=1 REACTION 1 REACTION 2 REACTION 3END


Appendix B - Keyword (.INP) Files - Metric UOM

Chiller Plant - Part 1TITLE DIMENSION SI, TEMP=C, XDENSITY=SPGR, STDTEMP=0, STDPRES=101.325 SEQUENCE SIMSCI CALCULATION RVPBASIS=APIN, TVP=37.778COMPONENT DATA LIBID 1,N2/2,CO2/3,METHANE/4,ETHANE/5,PROPANE/6,IBUTANE/7,BUTANE/ & 8,IPENTANE/9,PENTANE PETRO 10,C6PLUS,,0.691931,98.889 PHASE VL=10THERMODYNAMIC DATA METHOD SYSTEM=PR, TRANSPORT=PETR, SET=PR01, DEFAULTSTREAM DATA PROPERTY STREAM=INLET_GAS, TEMPERATURE=48.889, PRESSURE=1413.4, & PHASE=M, RATE(GV)=47194.9, COMPOSITION(M)=1,1/2,1.6/3,72.5/ & 4,11.5/5,6.75/6,1.25/7,3/8,0.55/9,1.1/10,0.75UNIT OPERATIONS FLASH UID=D-1 FEED INLET_GAS PRODUCT V=2, L=3 ISO TEMPERATURE=29.444, PRESSURE=1501 PUMP UID=P-1 FEED 3 PRODUCT M=17 OPERATION EFF=65, PRESSURE=3893.4 COMPRESSOR UID=C-1 FEED 2 PRODUCT V=4 OPERATION CALCULATION=ASME, PRES=4238.2, EFF=72 HX UID=HX-1 HOT FEED=4, M=5, DP=34.474 UTILITY AIR, TIN=26.667, TEMPERATURE=37.778 CONFIGURE COUNTER OPER HTEMP=43.333 FLASH UID=D-2 FEED 5 PRODUCT V=6, L=7 ADIABATICEND

Chiller Plant - Part 2TITLE DIMENSION SI, TEMP=C, XDENSITY=SPGR, STDTEMP=0, STDPRES=101.325 SEQUENCE SIMSCI CALCULATION RVPBASIS=APIN, TVP=37.778COMPONENT DATA LIBID 1,N2/2,CO2/3,METHANE/4,ETHANE/5,PROPANE/6,IBUTANE/7,BUTANE/ & 8,IPENTANE/9,PENTANE PETRO 10,C6PLUS,,0.691931,98.889 PHASE VL=10THERMODYNAMIC DATA METHOD SYSTEM=PR, TRANSPORT=PETR, SET=PR01, DEFAULTSTREAM DATA PROPERTY STREAM=INLET_GAS, TEMPERATURE=48.889, PRESSURE=1413.4, & PHASE=M, RATE(GV)=47194.9, COMPOSITION(M)=1,1/2,1.6/3,72.5/ & 4,11.5/5,6.75/6,1.25/7,3/8,0.55/9,1.1/10,0.75UNIT OPERATIONS COMPRESSOR UID=C-1 FEED 2 PRODUCT V=4 OPERATION CALCULATION=ASME, PRES=4238.2, EFF=72 FLASH UID=D-1 FEED INLET_GAS PRODUCT V=2, L=3 ISO TEMPERATURE=29.444, PRESSURE=1501 FLASH UID=D-2 FEED 5 PRODUCT V=6, L=7 ADIABATIC FLASH UID=D-3 FEED 9


PRODUCT V=10, L=11 ADIABATIC HX UID=HX-1 HOT FEED=4, M=5, DP=34.474 UTILITY AIR, TIN=26.667, TEMPERATURE=37.778 CONFIGURE COUNTER OPER HTEMP=43.333 HX UID=HX-2 HOT FEED=6, M=8, DP=34.474 COLD FEED=10, M=12, DP=34.474 CONFIGURE COUNTER OPER HICO=5.5556 HX UID=HX-3 HOT FEED=8, M=9, DP=34.474 UTILITY REFRIGERANT, COMPONENT=5, TSAT=-30 CONFIGURE COUNTER OPER HTEMP=-25 PUMP UID=P-1 FEED 3 PRODUCT M=17 OPERATION EFF=65, PRESSURE=3893.4 VALVE UID=V-1 FEED 11 PRODUCT M=13 OPERATION PRESSURE=1790.5END

Chiller Plant - Part 3TITLE DIMENSION SI, TEMP=C, XDENSITY=SPGR, STDTEMP=0, STDPRES=101.325 SEQUENCE SIMSCI CALCULATION RVPBASIS=APIN, TVP=37.778COMPONENT DATA LIBID 1,N2/2,CO2/3,METHANE/4,ETHANE/5,PROPANE/6,IBUTANE/7,BUTANE/ & 8,IPENTANE/9,PENTANE PETRO 10,C6PLUS,,0.691931,98.889 PHASE VL=10THERMODYNAMIC DATA METHOD SYSTEM=PR, TRANSPORT=PETR, SET=PR01, DEFAULTSTREAM DATA PROPERTY STREAM=INLET_GAS, TEMPERATURE=48.889, PRESSURE=1413.4, & PHASE=M, RATE(GV)=47194.9, COMPOSITION(M)=1,1/2,1.6/3,72.5/ & 4,11.5/5,6.75/6,1.25/7,3/8,0.55/9,1.1/10,0.75 PROPERTY STREAM=50, PRESSURE=180.62, PHASE=L, RATE(WT)=16735.9, & COMPOSITION(M)=4,2.5/5,97/6,0.5UNIT OPERATIONS COMPRESSOR UID=C-1 FEED 2 PRODUCT V=4 OPERATION CALCULATION=ASME, PRES=4238.2, EFF=72 CONTROLLER UID=CN1 SPEC STREAM=9, TEMPERATURE(F), VALUE=-15 VARY STREAM=50, RATE CPARAMETER IPRINT, NOSTOP FLASH UID=D-1 FEED INLET_GAS PRODUCT V=2, L=3 ISO TEMPERATURE=29.444, PRESSURE=1501 FLASH UID=D-2 FEED 5 PRODUCT V=6, L=7 ADIABATIC FLASH UID=D-3 FEED 9 PRODUCT V=10, L=11 ADIABATIC HX UID=HX-1 HOT FEED=4, M=5, DP=34.474 UTILITY AIR, TIN=26.667, TEMPERATURE=37.778 CONFIGURE COUNTER OPER HTEMP=43.333 HX UID=HX-2 HOT FEED=6, M=8, DP=34.474 COLD FEED=10, M=12, DP=34.474 CONFIGURE COUNTER OPER HICO=5.5556 HX UID=HX-3 HOT FEED=8, M=9, DP=34.474 COLD FEED=50, M=51

82 Appendix B - Keyword (.INP) Files - Metric UOM

CONFIGURE COUNTER OPER CLFRAC=0 PUMP UID=P-1 FEED 3 PRODUCT M=17 OPERATION EFF=65, PRESSURE=3893.4 VALVE UID=V-1 FEED 11 PRODUCT M=13 OPERATION PRESSURE=1790.5END

Chiller Plant -Part 4TITLE DIMENSION SI, TEMP=C, XDENSITY=SPGR, STDTEMP=0, STDPRES=101.325 SEQUENCE SIMSCI CALCULATION RVPBASIS=APIN, TVP=37.778COMPONENT DATA LIBID 1,N2/2,CO2/3,METHANE/4,ETHANE/5,PROPANE/6,IBUTANE/7,BUTANE/ & 8,IPENTANE/9,PENTANE PETRO 10,C6PLUS,,0.691931,98.889 PHASE VL=10THERMODYNAMIC DATA METHOD SYSTEM=PR, TRANSPORT=PETR, SET=PR01, DEFAULTSTREAM DATA PROPERTY STREAM=INLET_GAS, TEMPERATURE=48.889, PRESSURE=1413.4, & PHASE=M, RATE(GV)=47194.9, COMPOSITION(M)=1,1/2,1.6/3,72.5/ & 4,11.5/5,6.75/6,1.25/7,3/8,0.55/9,1.1/10,0.75 PROPERTY STREAM=50, PRESSURE=180.62, PHASE=L, RATE(WT)=16329.3, & COMPOSITION(M)=4,2.5/5,97/6,0.5UNIT OPERATIONS COLUMN UID=T-1 PARAMETER TRAY=13,IO FEED 13,1 PRODUCT OVHD(M)=14, BTMS(M)=15, SUPERSEDE=ON DUTY 1,13 PSPEC PTOP=1480.3, DPCOLUMN=17.237 PRINT PROPTABLE=PART ESTIMATE MODEL=CONVENTIONAL, RRATIO=3 SPEC STREAM=15, TVP(PSIG), VALUE=235 DEFINE PRODUCT(LBM/H)=14 AS STREAM=13, RATE(LBM/H), COMP=1,3, & WET VARY DUTY=1 REBOILER TYPE=KETTLE COMPRESSOR UID=C-1 FEED 2 PRODUCT V=4 OPERATION CALCULATION=ASME, PRES=4238.2, EFF=72 COMPRESSOR UID=C-2 FEED 14 PRODUCT V=16 OPERATION CALCULATION=ASME, PRES=4238.2, EFF=73 CONTROLLER UID=CN1 SPEC STREAM=9, TEMPERATURE(F), VALUE=-15 VARY STREAM=50, RATE CPARAMETER IPRINT, NOSTOP FLASH UID=D-1 FEED INLET_GAS PRODUCT V=2, L=3 ISO TEMPERATURE=29.444, PRESSURE=1501 FLASH UID=D-2 FEED 5 PRODUCT V=6, L=7 ADIABATIC FLASH UID=D-3 FEED 9 PRODUCT V=10, L=11 ADIABATIC HX UID=HX-1 HOT FEED=4, M=5, DP=34.474 UTILITY AIR, TIN=26.667, TEMPERATURE=37.778 CONFIGURE COUNTER OPER HTEMP=43.333 HX UID=HX-2 HOT FEED=6, M=8, DP=34.474 COLD FEED=10, M=12, DP=34.474 CONFIGURE COUNTER OPER HICO=5.5556 HX UID=HX-3


HOT FEED=8, M=9, DP=34.474 COLD FEED=50, M=51 CONFIGURE COUNTER OPER CLFRAC=0 MIXER UID=M-1 FEED 7,17 PRODUCT M=19 MIXER UID=M-2 FEED 16,12 PRODUCT M=18 PUMP UID=P-1 FEED 3,15 PRODUCT M=17 OPERATION EFF=65, PRESSURE=3893.4 VALVE UID=V-1 FEED 11 PRODUCT M=13 OPERATION PRESSURE=1790.5END

Gas Cooling

Process with Recycle StreamTITLE PRINT INPUT=NONE DIMENSION SI, TEMP=C, XDENSITY=SPGR, STDTEMP=0, STDPRES=101.325 SEQUENCE PROCESS CALCULATION RVPBASIS=APIN, TVP=37.778COMPONENT DATA LIBID 1,CO2/2,C1/3,C2/4,C3/5,IC4/6,NC4/7,IC5/8,NC5/9,NC6THERMODYNAMIC DATA METHOD SYSTEM=PR, SET=PR01STREAM DATA PROPERTY STREAM=1, TEMPERATURE=66, PRESSURE=24820, PHASE=M, & RATE(M)=455, COMPOSITION(M)=1,1.39/2,85.92/3,7.73/4,2.45/ & 5,0.36/6,0.56/7,0.21/8,0.26/9,1.12UNIT OPERATIONS VALVE UID=V1 FEED 1 PRODUCT M=2 OPERATION DP=11030 HX UID=E1 HOT FEED=2, M=3, DP=35 COLD FEED=6, M=8, DP=35 CONFIGURE COUNTER OPER HICO=8 VALVE UID=V2 FEED 3 PRODUCT M=4 OPERATION DP=6205 HX UID=E2 HOT FEED=4, M=5X, DP=35 OPER HTEMP=-29 FLASH UID=F1 FEED 5X PRODUCT V=6, L=7 ADIABATIC DP=0END

Process with Broken RecycleTITLE PRINT INPUT=NONE DIMENSION SI, TEMP=C, XDENSITY=SPGR, STDTEMP=0, STDPRES=101.325$$ Warning. Sequence switched to SimSci because insufficient$ information was available to write the Alternate sequence.$ SEQUENCE SIMSCI CALCULATION RVPBASIS=APIN, TVP=37.778COMPONENT DATA LIBID 1,CO2/2,C1/3,C2/4,C3/5,IC4/6,NC4/7,IC5/8,NC5/9,NC6THERMODYNAMIC DATA METHOD SYSTEM=PR, SET=PR01STREAM DATA


PROPERTY STREAM=1, TEMPERATURE=66, PRESSURE=24820, PHASE=M, & RATE(M)=455, COMPOSITION(M)=1,1.39/2,85.92/3,7.73/4,2.45/ & 5,0.36/6,0.56/7,0.21/8,0.26/9,1.12 PROPERTY STREAM=5, TEMPERATURE=-29, PRESSURE=7515, REFSTREAM=1UNIT OPERATIONS FLASH UID=F1 FEED 5 PRODUCT V=6, L=7 ADIABATIC DP=0 HX UID=E1 HOT FEED=2, M=3, DP=35 COLD FEED=6, M=8, DP=35 CONFIGURE COUNTER OPER HICO=8 HX UID=E2 HOT FEED=4, M=5X, DP=35 OPER HTEMP=-29 VALVE UID=V1 FEED 1 PRODUCT M=2 OPERATION DP=11030 VALVE UID=V2 FEED 3 PRODUCT M=4 OPERATION DP=6205END

MEK/Toluene PreheatTITLE DIMENSION SI, TEMP=C, XDENSITY=SPGR, STDTEMP=0, STDPRES=101.325 SEQUENCE PROCESS CALCULATION RVPBASIS=APIN, TVP=37.778COMPONENT DATA LIBID 1,MEK/2,TOLUENE/3,WATERTHERMODYNAMIC DATA METHOD SYSTEM=NRTL, ENTHALPY(V)=SRKM, DENSITY(V)=SRKM, SET=NRTL01, & DEFAULTSTREAM DATA PROPERTY STREAM=FEED, TEMPERATURE=88, PRESSURE=138, PHASE=M, & RATE(M)=45, COMPOSITION(M)=1,19/2,80/3,1UNIT OPERATIONS FLASH UID=FD FEED FEED PRODUCT V=VAPOR, L=S1 TPSPEC DP=7 SPEC STREAM=VAPOR, RATE(LBM/H),TOTAL,WET, DIVIDE, REFFEED, & RATE(LBM/H),WET, VALUE=0.4 HX UID=HX COLD FEED=S1, L=PROD, DP=7 DEFINE DUTY(KJ/HR) AS 1.05, MINUS, FLASH=FD, DUTY(KJ/HR)END

Naphtha Assay - Part 1TITLE DIMENSION SI, TEMP=C, XDENSITY=SPGR, STDTEMP=0, STDPRES=101.325 SEQUENCE SIMSCI CALCULATION RVPBASIS=APIN, TVP=37.778COMPONENT DATA LIBID 1,IBUTANE/2,BUTANE/3,IPENTANE/4,PENTANE ASSAY TBPIP=3 CUTPOINTS TBPCUTS=26.667,237.778,21/648.889,8/871.11,4THERMODYNAMIC DATA METHOD SYSTEM=SRK, SET=SRK01, DEFAULTSTREAM DATA PROPERTY STREAM=NAPHTHA_FEED, TEMPERATURE=37.778, PRESSURE=101.32, & PHASE=M, RATE(WT)=453.593, ASSAY=LV D86 STREAM=NAPHTHA_FEED, DATA=3,90/5,125/10,195/30,250/50,280/ & 70,310/90,390/95,418/98,430, TEMP=F API STREAM=NAPHTHA_FEED, AVERAGE=54.2 LIGHTEND STREAM=NAPHTHA_FEED, COMPOSITION(M)=1,0.7/2,2.15/3,0.86/ & 4,3.58, PERCENT(LV)=5, NORMALIZE


Naphtha Assay - Part 2TITLE DIMENSION SI, TEMP=C, PRES=ATM, XDENSITY=SPGR, STDTEMP=0, STDPRES=1 SEQUENCE SIMSCI CALCULATION RVPBASIS=APIN, TVP=37.778COMPONENT DATA LIBID 1,IBUTANE/2,BUTANE/3,IPENTANE/4,PENTANE ASSAY TBPIP=3 CUTPOINTS TBPCUTS=26.667,237.778,21/648.889,8/871.11,4THERMODYNAMIC DATA METHOD SYSTEM=SRK, SET=SRK01, DEFAULTSTREAM DATA PROPERTY STREAM=NAPHTHA_FEED, TEMPERATURE=38, PRESSURE=1, PHASE=M, & RATE(WT)=450, ASSAY=LV D86 STREAM=NAPHTHA_FEED, DATA=3,90/5,125/10,195/30,250/50,280/ & 70,310/90,390/95,418/98,430, TEMP=F SPGR STREAM=NAPHTHA_FEED, AVERAGE=0.762 LIGHTEND STREAM=NAPHTHA_FEED, COMPOSITION(M)=1,0.7/2,2.15/3,0.86/ & 4,3.58, PERCENT(LV)=5, NORMALIZEUNIT OPERATIONS FLASH UID=F1 FEED NAPHTHA_FEED PRODUCT V=F1VAPOR, L=F1LIQUID TPSPEC PRESSURE=0.8 SPEC STREAM=F1VAPOR, RATE(LBM/H),TOTAL,WET, DIVIDE, & STREAM=NAPHTHA_FEED, RATE(LBM/H),TOTAL,WET, & VALUE=0.8 FLASH UID=F2 FEED F1VAPOR PRODUCT V=F2VAPOR, L=F2LIQUID ISO DP=0.1 DEFINE TEMP(F) AS STREAM=F1VAPOR, TEMPERATURE(F), MINUS,18END

Naphtha Assay - Part 3TITLE DIMENSION SI, TEMP=C, PRES=ATM, XDENSITY=SPGR, STDTEMP=0, STDPRES=1 SEQUENCE SIMSCI CALCULATION RVPBASIS=APIN, TVP=37.778COMPONENT DATA LIBID 1,IBUTANE/2,BUTANE/3,IPENTANE/4,PENTANE ASSAY TBPIP=3 CUTPOINTS TBPCUTS=26.667,237.778,21/648.889,8/871.11,4THERMODYNAMIC DATA METHOD SYSTEM=SRK, SET=SRK01, DEFAULTSTREAM DATA PROPERTY STREAM=NAPHTHA_FEED, TEMPERATURE=38, PRESSURE=1, PHASE=M, & RATE(WT)=450, ASSAY=LV D86 STREAM=NAPHTHA_FEED, DATA=3,90/5,125/10,195/30,250/50,280/ & 70,310/90,390/95,418/98,430, TEMP=F SPGR STREAM=NAPHTHA_FEED, AVERAGE=0.762 LIGHTEND STREAM=NAPHTHA_FEED, COMPOSITION(M)=1,0.7/2,2.15/3,0.86/ & 4,3.58, PERCENT(LV)=5, NORMALIZEUNIT OPERATIONS FLASH UID=F1 FEED NAPHTHA_FEED PRODUCT V=F1VAPOR, L=F1LIQUID TPSPEC PRESSURE=0.8 SPEC STREAM=F1VAPOR, RATE(LBM/H),TOTAL,WET, DIVIDE, & STREAM=NAPHTHA_FEED, RATE(LBM/H),TOTAL,WET, & VALUE=0.8 FLASH UID=F2 FEED F1VAPOR PRODUCT V=F2VAPOR, L=F2LIQUID ISO DP=0.1 DEFINE TEMP(F) AS STREAM=F1VAPOR, TEMPERATURE(F), MINUS,18CASESTUDY OLDCASE=BASECASE, NEWCASE=CS1 PARAMETER ID=F1SPLIT, FLASH=F1, SPEC(1),STEP(ACT)=-0.1, CYCLES =1,5 RESULT ID=F2DUTY, FLASH=F2, DUTY(KJ/HR)END


Phase EnvelopeTITLE PROJECT=TRAINING, PROBLEM=RETROGRADE C, DIMENSION SI, TEMP=C, XDENSITY=SPGR, STDTEMP=0, STDPRES=101.325 SEQUENCE SIMSCI CALCULATION RVPBASIS=APIN, TVP=37.778COMPONENT DATA LIBID 1,C1/2,C2/3,C3/4,IC4/5,NC4/6,IC5THERMODYNAMIC DATA METHOD SYSTEM=SRK, SET=SRK01, DEFAULTSTREAM DATA PROPERTY STREAM=S1, TEMPERATURE=66, PRESSURE=17240, PHASE=M, & RATE(M)=45, COMPOSITION(M)=1,82/2,7/3,4/4,2/5,2/6,3UNIT OPERATIONS PHASE UID=PH1 EVAL STREAM=S1, LFRAC=0, IPLOT=OFF, CPLOT=1 EVAL STREAM=S1, LFRAC=0.05,IPLOT=OFF, CPLOT=2 EVAL STREAM=S1, LFRAC=0.1,IPLOT=OFF, CPLOT=3 EVAL STREAM=S1, LFRAC=0.15,IPLOT=OFF, CPLOT=4 EVAL STREAM=S1, LFRAC=1,IPLOT=OFF, CPLOT=5END

Compressor CurvesTITLE DIMENSION SI, TEMP=C, XDENSITY=SPGR, STDTEMP=0, STDPRES=101.325 SEQUENCE SIMSCI CALCULATION RVPBASIS=APIN, TVP=37.778COMPONENT DATA LIBID 1,C2/2,C3/3,IC4/4,NC4THERMODYNAMIC DATA METHOD SYSTEM=SRK, SET=SRK01, DEFAULTSTREAM DATA PROPERTY STREAM=S1, TEMPERATURE=-9.2, PRESSURE=2172, PHASE=M, & RATE(M)=7485.01, COMPOSITION(M)=1,1.04/2,96.94/3,1.68/4,0.34UNIT OPERATIONS VALVE UID=V1 FEED S1 PRODUCT M=S2 OPERATION PRESSURE=600 HX UID=E1 HOT FEED=S2, L=S5, V=S4, DP=30 OPER DUTY=2.11 HX UID=E2 HOT FEED=S5, M=S6, DP=61 OPER HDTADEW=5.5556E-16 MIXER UID=M1 FEED S4,S6 PRODUCT M=S7 OPERATION PRESSURE=450 COMPRESSOR UID=C1 FEED S7 PRODUCT V=S8 HEAD ACTUAL=25485,11582/28317,11278/35113,10760/ & 38511,10089/40493,8306 EFFICIENCY ADIA=25485,69/283179,71/35113,72/38511,73/ & 40493,71 OPERATION CALCULATION=ASMEEND

DebutanizerTITLE DIMENSION SI, TEMP=C, STDTEMP=0, STDPRES=101.325 SEQUENCE SIMSCI CALCULATION RVPBASIS=APIN, TVP=37.778COMPONENT DATA LIBID 1,H2/2,H2S/3,C1/4,C2/5,C3/6,IC4/7,NC4/8,IC5/9,NC5THERMODYNAMIC DATA METHOD SYSTEM=SRK, SET=SRK01, DEFAULTSTREAM DATA PROPERTY STREAM=LPG, TEMPERATURE=40, PRESSURE=1860, PHASE=M, & RATE(LV)=11.3, COMPOSITION(M)=1,0.3/2,0.2/3,0.7/4,5.5/5,28.5/ & 6,11.7/7,49/8,4.1 PROPERTY STREAM=NAPHTHA, TEMPERATURE=40, PRESSURE=1860, PHASE=M, & RATE(LV)=90, ASSAY=LV D86 STREAM=NAPHTHA, DATA=0,40/5,62/10,70/30,91/50,109/70,120/ &


90,140/95,155/100,165, TEMP=C SPGR STREAM=NAPHTHA, AVERAGE=0.75 LIGHTEND STREAM=NAPHTHA, COMPOSITION(LV)=5,0.07/6,0.21/7,0.42/ & 8,3.24/9,6.06, PERCENT(LV)=10, NORMALIZEUNIT OPERATIONS FLASH UID=F1 FEED LPG,NAPHTHA PRODUCT L=CFEED ISO TEMPERATURE=170, PRESSURE=1860 COLUMN UID=DEBU PARAMETER TRAY=32,IO FEED CFEED,15 PRODUCT OVHD(M)=OVHD, BTMS(M)=BTMS, SUPERSEDE=ON CONDENSER TYPE=BUBB, PRESSURE=1275 DUTY 1,1/2,32 PSPEC PTOP=1310, DPCOLUMN=30 PRINT PROPTABLE=PART ESTIMATE MODEL=CONVENTIONAL, RRATIO=3 SPEC STREAM=OVHD, RATE(LBM/H), COMP=6,7,WET, DIVIDE, & STREAM=CFEED, RATE(LBM/H), COMP=6,7,WET, VALUE=0.99 SPEC STREAM=OVHD, RATE(LBM/H), COMP=8,9,WET, DIVIDE, & STREAM=CFEED, RATE(LBM/H), COMP=8,9,WET, VALUE=0.01 DEFINE PRODUCT(LBM/H)=OVHD AS STREAM=CFEED, RATE(LBM/H), & COMP=1,7,WET VARY DUTY=1,2 REBOILER TYPE=KETTLEEND

Two Stage CompressorTITLE PRINT STREAM=ALL, RATE=M, FRACTION=M DIMENSION SI, TEMP=C, PRES=BAR, STDTEMP=0, STDPRES=1.01325 SEQUENCE SIMSCI CALCULATION RVPBASIS=APIN, TVP=37.778COMPONENT DATA LIBID 1,NITROGEN/2,CO2/3,METHANE/4,ETHANE/5,PROPANE/6,IBUTANE/ & 7,NBUTANE/8,IPENTANE/9,PENTANE/10,HEXANE/11,NC9THERMODYNAMIC DATA METHOD SYSTEM=PR, DENSITY(L)=COST, SET=PR01, DEFAULTSTREAM DATA PROPERTY STREAM=S1, TEMPERATURE=40, PRESSURE=5, PHASE=M, & COMPOSITION(M,KGM/H)=1,180/2,1920/3,14520/4,9070/5,7260/6,770/ & 7,2810/8,950/9,1630/10,1540/11,3180 NAME S1,Feed/S3,Liquid Product/S5,HX-1 Outlet/S9,HX-2 Outlet/ & S10,Vapor ProductUNIT OPERATIONS COMPRESSOR UID=C-1 FEED S2 PRODUCT V=S4 OPERATION CALCULATION=ASME, PRES=12, EFF=74 COMPRESSOR UID=C-2 FEED S6 PRODUCT V=S8 OPERATION CALCULATION=ASME, PRES=26, EFF=72 FLASH UID=D-1 FEED S1,S7 PRODUCT V=S2, L=S3 ADIABATIC FLASH UID=D-2 FEED S5,S11 PRODUCT V=S6, L=S7 ADIABATIC FLASH UID=D-3 FEED S9 PRODUCT V=S10, L=S11 ADIABATIC HX UID=HX-1 HOT FEED=S4, M=S5, DP=0.35 OPER HTEMP=60 HX UID=HX-2 HOT FEED=S8, M=S9, DP=0.35 OPER HTEMP=60END


Propylene Chlorination ReactorTITLE DIMENSION METRIC, STDTEMP=0, STDPRES=1.03323 SEQUENCE SIMSCI CALCULATION RVPBASIS=APIN, TVP=37.778COMPONENT DATA LIBID 1,CL2/2,C3H6/3,C3H5CL/4,HCL/5,C3H6CL2/6,C3H4CL2THERMODYNAMIC DATA METHOD SYSTEM=SRK, DENSITY(L)=COST, SET=SRK01, DEFAULTSTREAM DATA PROPERTY STREAM=S1, TEMPERATURE=15, PRESSURE=14, PHASE=M, & RATE(M)=100, COMPOSITION(M)=2,1 PROPERTY STREAM=S2, TEMPERATURE=26, PRESSURE=7, PHASE=M, & RATE(M)=115, COMPOSITION(M)=1,1RXDATA RXSET ID=1 REACTION ID=1 STOICHIOMETRY 1,-1/2,-1/3,1/4,1 KINETICS PEXP=2.1E11, ACTIVATION=15.005, TEXPONENT=0 KPHASE DEFAULT=V REACTION ID=2 STOICHIOMETRY 1,-1/2,-1/5,1 KINETICS PEXP=1.19E7, ACTIVATION=3.7844, TEXPONENT=0 KPHASE DEFAULT=V REACTION ID=3 STOICHIOMETRY 1,-1/3,-1/4,1/6,1 KINETICS PEXP=4.69E14, ACTIVATION=23.5, TEXPONENT=0 KPHASE DEFAULT=VUNIT OPERATIONS CSTR UID=R1 FEED S1,S2 PRODUCT M=S3 OPERATION VOLUME=0.3, PRESSURE=5, TEMPERATURE=425 FESTIMATE 1,1.15 RXSTOIC RXSET=1 REACTION 1 REACTION 2 REACTION 3END


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