ProII Basics

7/29/2019 ProII Basics

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Introduction to Pro/II

Process Simulation using PRO/II's GUI

General Approach to Simulation

red borders - operations required, and data fields where data entry is needed

green borders - Data entry fields with supplied defaults. After supplying information in an entry field, the

border changes to blue. If you supply data outside the normal range of values for a field, a yellow border

appears.

Data may be supplied in almost any order; PRO/II warns you when required data are missing.

However, the following general approach is recommended:

1. Draw the flowsheet and connect the unit operations with streams.

The icons and names for the unit operations appear in the PFD Palette which may be moved or resized as

desired. To add a unit operation to the flowsheet, click the unit icon in the palette, move the cursor to the

desired location on the draw area, and click the left mouse button. The icon for the unit will be placed on theflowsheet.

e.g., For a flash calculation:

o Click on the flash drum (located in panel on RHS).

o Mover cursor to Pro II Flowsheet and click mouse

o From the PFD Palette, push the Stream button. The cursor changes its shape to and all

possible exit ports for each unit operation are now marked. Required outlet ports are red; optional

ports are green.

o

2. Define the components in your system.It is best to order the components in volatility order, starting with the lightest component. While not a

necessity, defining water as the first component in hydrocarbon/water systems makes it easy to see the break

between the aqueous and non-aqueous phases. Petroleum components for which you supply data should bedefined next. Pseudocomponents generated by PRO/II from petroleum stream assay data are the last

components in the component list.

3. Select the thermodynamic and transport property methods.For many problems, a predefined method set may be selected. Guidelines for thermodynamic methods are

provided in the PRO/II on-line help and Reference Manual (accessed via the Help Menu), and the hard copy

PRO/II Reference Manual. Hot line help is also available from SimSci.

4. Supply data for the feed streams and recycle streams.You must supply thermal conditions, flowrates, and compositions for all external feed streams to the flowsheet.

Optionally, estimated data may be supplied for recycle streams to speed convergence of recycle calculations.

5. Supply operating conditions for the unit operations. Double-click on the icon for each unit operation to access its data entry windows. The color codes tell you what

data you must supply and what data have defaults. You may also use the on-line help (accessed via the Help

button) to learn more about the calculation options, data entry items, etc.



1. Starting Pro/II

1.1. Go to “Start” menu

- Click on the “Remote Desktop Connection” bar - Click on “Connect”

- Click on “Connect” again

1.2. Enter your Password; Click “Yes” to “Do you want to connect despite these certificate errors?”



1.3. Double Click desired program icon, e.g., MatLab, Mathcad, ProII 9.0

1.4. You will now get a screen that looks like this for ProII

1.5. Click OK

1.6. To open a new Process Flow Diagram (PFD):

- Click the icon or- File Menu New

You get a screen like that below and you are ready to enter Process information.



2. Adding Chemical Components

2.1. To add new chemical components:

- Click the icon or

- Input Menu Component Selection…

2.2. To select chemical components:- Type them directly into the “Component” field; then click the “Add” button each time.

- Or Click the button.

- After selecting each component Click the “Add Components” button to move to the Component List



2.3. To select a custom Petroleum based chemical component:

- Click the button.

- Note: “Petroleum…” only requires a normal boiling point and standard liquid density for Pro II touse. Although not necessary, it is strongly recommended that the user input the molecular weight.

- I ended with the following set of components which I will then seek to separate:

2.4. To select a custom User-defined chemical component:

- Click the button.

- Note: “User -defined…” components require the user to specify most of the thermophysical

properties of the component.

2.5. After all components have been added, Click “OK” to close each open Component Selection window(number of windows will vary depending on type of components selected).

2.6. Now (and often!) is a good time to save your work. You can save it on the Server, but files getremoved; therefore, I suggest you save it on your own laptop similar to what I have done below. I

confirmed this with our Laboratory Instructional Supervisor, Dr. Paul Golter and this is what he says:

“Yes, anything stored on the server is very very likely to disappear”.



3. Setting the Units

- To set units: Click the icon or

- Input Menu Units of Measure… - Then use “”to select from a list of options, e.g., for Vapor Density pick Kilogram/meter^3

3.1. Note: The user can also set the atmospheric pressure if working in gauge pressure by modifying the“Pressure Gauge Basis.”

3.2. Press “OK” when done.

3.3. Now (and often) is a good time to save your work.



4. Selecting the Thermodynamic Package

4.1. To select the thermodynamic package:

- Click the icon or- Input Menu Thermodynamic Data… - Pick a Category, e.g., Most Commonly Used; then the Primary Method: e.g. Peng-Robinson; you

may pick more than one Primary Method, e.g., Ideal to be used later for low pressure gas phase

calculations, whereas the Peng-Robinson to be used for high pressure gas phase and liquid phasecalculations. You may also need Liquid Activity (i.e. activity coefficients) determined using van Laar ,

Wilson, NRTL (Non-Random Two Liquid model), etc. Click to select; appear as NRTL01.

- Finally, click OK

4.2. Note: Once a thermodynamic package has been added to the system, it can be removed by selecting it

in the “Defined Systems:” list and clicking the button.

4.3. Again this is a good time to save your work.



5. Working with the Process Flow Diagram (PFD)

5.1. To show the PFD Palette:

- Click the icon or- View menu PFD Palette

5.2. To add unit operations to the PFD:

- First, click on the desired unit operation on the PFD Palette. Under the General tab pick a Flash unit.- Second, click in the PFD work space where the unit operation should be located.

- For a reactor or distillation column click the appropriate tab, e.g., Column & select the column type

you will need specify the Number of Theoretical Trays before the column will insert.

5.3. To connect unit operations with Streams:

- First, click the button on the PFD Palette- Second, click and drag between unit operations or click on the white background and drag to a unit

operation (input and output streams).



5.4. Note: when the Streams button has been pressed, all available connections become visible.

- A required connection will be colored red, while an optional connection will be colored green.

- Some unit operations, like flash drum and distillation columns, have a general input on their sides.

This is indicated when the entire side is highlighted red (or green once a stream is connected).

- In the case of a distillation column, only after the feed tray has been specified will ProII fix where

the stream is connected.

5.5. Once all required streams are connected, only green connections will be left while “Streams” is selectedin the PFD Palette.

5.6. Again this is a good time to save your work.

6. Specifying Streams

6.1. To specify stream characteristics:

- Double-click on the name of the stream



6.2. Note: The Stream name appears at the top of the window. Rename and/or add a description here.

There’s a maximum of 12 characters, all upper case.

6.3. Note: Only two Thermal Conditions are used in characterizing a stream:

- The first one must be either temperature or pressure.

- The second can be: temperature, pressure (which ever was not used as the first), bubble point, dew

point, liquid mole fraction, liquid weight fraction or liquid volume fraction.

- The two thermal conditions are not enough to fully characterize the stream.

6.4. To specify the flow rate and composition of a stream:

- Click the button.

6.5. To change the measurement units for the flowrate:- First, click on the desired Fluid Flowrate Specification

- Next, click UOM and you will get the following screen

- Second, enter the desired units and click on Change Units



6.6. Note: Required fields are bordered in red.

- Once data has been entered in a field, the border will change to blue. You can also put in total moles

of each component and ask ProII to Normalize to obtain compositions by checking the box.

- Pro II will not auto-fill the last component to make the total mole or mass fraction 1.00.



6.7. Again save your work.

7. Checking the System

7.1. Streams that must be defined will have their name highlighted red.

- Dependent streams that do not need to be specified will have their names black.

7.2. Unit operations that are not fully defined will have the name highlighted red.

- Once a unit operation is properly defined the name will simply appear black.

7.3. Note: An easy check to determine if the PFD is ready to calculate is to be sure that there are no red

highlighted streams or unit operations. Once all streams and unit operations are properly defined, the

PFD can be run.

7.4. Let’s go ahead and fill in the information for each unit in our process:

7.4.1. For the first 1st

Flash unit we want to use it to see if we can separate the octane out as a liquid;

the problem is that n-octane has a high vapor pressure and water has a vapor pressure as well, sowe may need to remove some heat to get the temperature down and hopefully liquefy of the n-

octane. We can tell ProII we want to remove 0.5 kg-mol/hr (i.e. 0.05 x 10 kg-mol/hr feed) and see

what happens. We do this by choosing Product Specification, and going to the

highlight. Click on Parameter and select stream S2, then click

on Parameter again and select “Flowrate” and then “All Components”



7.4.2. Then and set it to 0.5; we can put in a temperature estimate, but Pro II will do this for us aswell. Click “OK” to conclude the exercise.

7.4.3. Now let’s double click on the compressor and put in a pressure of 10 atm.

7.4.4. Now let’s cool the exit stream of the compressor to see if that will help in the next flash unit sowe don’t have to cool as much there to remove the water and any leftover n-octane.

7.4.5. Now let’s look at the final flash unit. Let’s give it a pressure drop of 5.0 atm and keep the

temperature constant at 300.00K.7.4.6. Now the final PFD will look like this with all streams in black:



7.5. To run the PFD:

- Click the icon and it will now have a black outline if the run is successful:

- To indicate the process has converged all the Processes will turn blue. If there’s a problem with one

or more processes the offending process will turn red (e.g., selecting a ΔP that goes below 0.0).




8. Viewing and Printing Data

8.1. To view stream properties (after running the PFD):

- First, right-click the stream of interest.- Second, select View Results.

8.2. To view unit operation properties (after running the PFD):

- First, right-click the unit operation of interest such as the first Flash

Unit

- Second, select View Results and for the Flash Unit #1 you get theinformation to the right.

8.3. Of course we can now view similar information for each stream in the

same way.

- Let’s do this for liquid stream exiting the first Flash unit. We get the

summary below.

- We see we have successfully removed most of the Octane when we look at the vapor fractioncomposition:

- We can now add a compressor to pressurize the vapor and add a heat exchanger to reduce thetemperature before entering another Flash Unit. Note that ProII will give an error if we don’t have aThermodynamic package that allows for an entropy calculation (remember we typically use anefficiency in a compressor and base calculations on an ideal 100% efficient adiabatic reversible or

isentropic compressor). Therefore we need to specify something like Peng Robinson for our

Equation of State. At the same time ProII will complain with a Warning if we change

Thermodynamic packages – we note that activity coefficients are needed for a flash unit if there is

vapor and liquid in equilibrium. We can ignore the Warning by pressing since weknow that doing so will not result in a problem.



- It’s interesting if we reduce the temperature too much we get water condensation & a Decant stream

and of course any leftover n-Octane forms its own liquid stream (w/ soluble CO2 & CO) since it

isn’t miscible with water . For example, if we see if we designate a 300K exit from the HtX we get:

- Let’s instead reduce the temperature to something higher like 400K and look at the exit from the

HtX, and Vapor and Liquid from the 2nd

Flash unit, respectively:

8.4. To generate a report:

- Click the icon or- Output Menu Generate Text Report…

- This will summarize all of the data in the PFD.- Note: the user can define the measurement units to be used in the report (they do not have to be the

same as the units used to run the PFD), the data to be included in the report, and the stream and unit

operations to be reported.

HtX Out Flash #2 V Flash #2 L



8.5. To print the report:- Press the keyboard short cut ctrl+P or

- File Menu Print.

- Or just save the report and print it from your PC at your own printer; below is an excerpt:

SIMULATION SCIENCES INC. R PAGE P-9

PROJECT PRO/II VERSION 9.0 ELEC V7.0

PROBLEM OUTPUT

STREAM MOLAR COMPONENT RATES 03/28/12

==============================================================================

STREAM ID S1 S2 S3 S4

NAMEPHASE VAPOR VAPOR LIQUID MIXED

THERMO ID NRTL01 NRTL01 NRTL01 PR01

FLUID RATES, KG-MOL/HR

1 CO2 5.0000 4.9808 0.0192 0.0192

2 CO 3.0000 2.9994 6.3303E-04 6.3303E-04

3 H2 1.0000 0.9998 1.9844E-04 1.9844E-04

4 H2O 0.5000 0.4902 9.7894E-03 9.7894E-03

5 ACETIC 0.0000 0.0000 0.0000 0.0000

6 NONANE 0.0000 0.0000 0.0000 0.0000

7 OCTANE 0.5000 0.0298 0.4702 0.4702

TOTAL RATE, KG-MOL/HR 10.0000 9.5000 0.5000 0.5000

TEMPERATURE, K 450.0000 280.8806 280.8806 274.6304

PRESSURE, ATM 10.0000 2.0000 2.0000 2.0000

ENTHALPY, MM BTU/HR 0.1723 0.0708 8.7277E-04 8.7277E-04

MOLECULAR WEIGHT 37.2219 33.4180 109.4971 109.4971

MOLE FRAC VAPOR 1.0000 1.0000 0.0000 6.7343E-03

MOLE FRAC TOTAL LIQUID 0.0000 0.0000 1.0000 0.9933

MOLE FRAC H/C LIQUID 0.0000 0.0000 1.0000 0.9739

MOLE FRAC FREE WATER 0.0000 0.0000 0.0000 0.0193


Decant Information

Note when water is present in hydrocarbon systems we often have a special case especially important in

separations such as what occurs flash units. ProII help menu gives:

A special case occurs when handling mixtures that form water as a nearly pure immiscible phase. Suchsystems are common in hydrocarbon-water mixtures in refinery and gas processing plants. For engineeringpurposes, it may often be assumed that the water phase is pure which reduces the computational timerequired to solve these simulations with rigorous VLLE models. When performing this calculation, PRO/II firstseeks to satisfy the partial pressure of water as given in the steam tables. When the vapor phase is fully



saturated and the hydrocarbon is saturated with water according to its water solubility, all remaining water isdecanted into the pure water phase.

- More information is given in the ProII help menu when you search for “Decant”: Water Decant OptionsFor most hydrocarbon-water mixtures found in refinery and gas plant operations the free water phase that forms is nearlyimmiscible with the hydrocarbon liquid phase. For such systems the three phase calculations may be modeled bydecanting the free water as a pure aqueous phase. This greatly simplifies the VLLE calculations.The free water decant option follows these steps:

The water vapor is assumed to form an ideal mixture with the hydrocarbon vapor phase.The quantity of water in the vapor phase is predicted with an equilibrium calculation which uses the following expressionfor the K-value of water:

:See Water Partial Pressure Calculations and Water Solubility Methods for more information.The vapor phase is checked for water saturation. If the partial pressure of the water in the vapor ( mole fraction timessystem pressure) exceeds the partial pressure for water at the system temperature, free water will form.

When free water will form, the vapor is saturated with water, i.e., the water content of the vapor is set such that the partialpressure of water in the vapor is equal to the saturation pressure for water at the system temperatureWater is dissolved in the hydrocarbon liquid up to its solubility limit.The remaining liquid water is decanted as a pure water stream.The free water decant option is limited to these K-value (VLE) methods: Soave-Redlich-Kwong, Peng-Robinson, Grayson-Streed options, Chao-Seader options, Braun-K10, and Benedict-Webb-Rubin-Starling. The water decant option isautomatically activated when any of these methods is selected. Additionally, the free water decant option can be used with the Regular Solution theory, which is generally considered tobe a liquid activity method. However, water decant is possible because Regular Solution Theory includes simplifyingassumptions from Scatchard and Hildebrand that consider liquid activity coefficients as functions only of pure component

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