Optimization of Heavy Oil Stripper

CH E 465 – Chemical Engineering Design II

Team 25 – A++Engineering

April 9th, 2015

Ammar Al-Qabbas

Fairuz Mustafa

Josh Idowu

Ryan Dinn

Siti Nasir

Fairuz Mustafa

Executive Summary

Shell Canada provided A++ Engineering with an opportunity to contribute to the optimization of

the heavy oil stripper unit within the Scotford Upgrader located in Fort Saskatchewan, Alberta. The

primary driver of this project is economic because the heavy oil stripper is fully operational and Shell

Canada is simply looking for improvements to the process. The business objective is to implement an

optimization to the unit that does not require a drastic amount of capital investment.

Three main categories of project solutions were explored for the project. The first was to follow

Shell Canada’s recommendation to target a reduction in pressure drop of the overhead system in order

to lower the operating pressure of the heavy oil stripper. The second was to consider an optimization of

the current operating conditions of the heavy oil stripper. The third and final subset of solutions

considered was physical modifications to the tower that could potentially increase the quality of

production of the unit. A total of eleven cases were considered in the development of the solution.

Ultimately, A++ Engineering has suggested that Shell Canada implement a modification to the

current heat exchanger network and overhead system piping. The project required a capital investment

of approximately $2,000,000 with an internal rate of return of 78% considered over a project life of ten

years. The solution will be implemented during the heavy oil stripper’s scheduled turnaround in the year

2019. A project execution strategy has been designed such that all construction and commissioning will

occur during the turnaround. A++ Engineering has produced a design basis memoranda level report that

can be used to take this project to the next stage of development.

1

Table of Contents List of Tables and Figures .............................................................................................................................. 3

1.0 Introduction and Statement of Objectives ............................................................................................. 3

2.0 Background ............................................................................................................................................. 4

3.0 Optimization Cases Considered .............................................................................................................. 5

3.1 Reduce Pressure Drop in Overhead System to Lower Tower Operating Pressure ............................. 6

3.1.1 Case 1: Modifications to Existing Heat Exchangers ..................................................................... 6

3.1.2 Case 2: Modifications to Surge and Knockout Drums .................................................................. 6

3.1.3 Case 3: Modifications to Overheads Heat Exchanger Network ................................................... 7

3.1.4 Case 4: Re-Routing Overheads Piping to Shorten Distance and Pressure Drop .......................... 7

3.1.5 Case 5: Increasing Diameter of Overheads Piping ....................................................................... 8

3.2 Optimization of Tower Operating Conditions ..................................................................................... 8

3.2.1 Case 6: Optimization of HOS Pumparounds ................................................................................ 8

3.2.1 Case 7: Optimization of Steam Flowrate ..................................................................................... 9

3.2.2 Case 8: Optimization of Feed Conditions ..................................................................................... 9

3.3 Physical Modifications to the Stripping Tower ................................................................................. 10

3.3.1 Case 9: Complete Tower Re-Design ........................................................................................... 10

3.3.2 Case 10: Add Additional/More Efficient Packed Beds ............................................................... 10

3.3.3 Case 11: Install Overheads Compressor ..................................................................................... 11

3.4 Do Nothing Case ................................................................................................................................ 11

3.4.1 Case 12: Maintain Current Operating Conditions ...................................................................... 11

4.0 Proposed Solution ................................................................................................................................. 11

5.0 Justification ........................................................................................................................................... 12

6.0 Process Description ............................................................................................................................... 13

6.1 Process Description ........................................................................................................................... 13

6.2 Stripping Tower Simulation & Validation .......................................................................................... 13

6.3 Main Process Flowsheet (PFD) for Base Case Simulation & Proposed Solution ............................... 15

6.4 Summary of Material & Energy Balances ......................................................................................... 15

6.5 Equipment List & Summary of Design Specifications and Optimization .......................................... 18

6.5.1 Heat Exchanger (E-210A) ........................................................................................................... 18

6.5.2 Design of Heat Exchanger (E-230) .............................................................................................. 21

6.5.3 Line Diameter Sensitivity Analysis ............................................................................................. 22

2

6.6 Utility Requirements ......................................................................................................................... 25

6.7 HAZOP and P&ID ............................................................................................................................... 25

6.8 DOW FEI & CEI ................................................................................................................................... 28

6.9 Pressure Relief Valve (PRV) ............................................................................................................... 28

6.10 Process Control ............................................................................................................................... 29

6.11 Plot Plan .......................................................................................................................................... 31

6.12 Effect on Upstream and Downstream units ................................................................................... 31

6.12.1 Atmospheric Distillation Tower ............................................................................................... 31

6.12.2 Hydrotreater ............................................................................................................................ 31

6.13 Environmental/Legislative Considerations ..................................................................................... 32

6.14 Assumptions, Limitations, and Constraints..................................................................................... 32

6.15 Project Execution Strategy .............................................................................................................. 32

6.15.1 Engineering Plan ...................................................................................................................... 33

6.15.2 Procurement Plan .................................................................................................................... 33

6.15.3 Construction Plan ..................................................................................................................... 34

6.15.4 Project Schedule ...................................................................................................................... 34

6.16 HOS Start-Up/Shut-Down Procedure .............................................................................................. 34

7.0 Economic Analysis ................................................................................................................................. 35

7.1 Total Module Cost Estimation ........................................................................................................... 35

7.1.1 Initial Unit Capital Costs ............................................................................................................. 35

7.1.2 Location Effects .......................................................................................................................... 36

7.1.3 Field vs. Shop Fabrication .......................................................................................................... 36

7.1.4 Work Included and Excluded ..................................................................................................... 36

7.1.5 Other Capital Cost Factors ......................................................................................................... 37

7.2 Working Capital Estimation .............................................................................................................. 37

7.3 Operating Costs ................................................................................................................................. 37

7.4 Project Management Schedule ......................................................................................................... 38

7.5 Plan for Financing .............................................................................................................................. 38

7.6 Cash Flow Analysis ............................................................................................................................ 38

7.7 Sensitivity Analysis ............................................................................................................................ 39

7.8 Discussion of Economics ................................................................................................................... 39

8.0 Recommendations and Conclusions ..................................................................................................... 40

9.0 References ............................................................................................................................................ 40