Marathon Petro-SIM use at Marathon Thomas Bowman Software user conference 2018, USA

1. Petro-SIM use at Marathon Petroleum Company
Thomas L. Bowman
Refining Operations Research

2. Topics
 Introduction
 Petro-SIM use for flowsheet modeling
 Conversion of FCC models to v6.2
 LP submodel development
 Refinery-wide modelling
 Crude assays from Spiral Assay
 Tips/ Tricks
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3. Introduction
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 MPC is the second-largest crude oil refiner in the U.S. and the largest in the
Midwest.
 MPC has 6 refineries located in the Midwest and Gulf Coast regions of the U.S.
 These refineries collectively have approximately 1,881,000 bpcd of crude oil
throughput capacity.
 This presentation shows some of the ways MPC uses Petro-SIM to model these
refineries.
 The focus will be on the work done by our Operations Research team using
Petro-SIM.

4. Petro-SIM use for flowsheet modeling
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 Transitioned refinery Technical Service team models to Petro-SIM
– Operations Research team converted ~500 models
– Training classes led by KBC consultants were held at each refinery
– Some models were modified to include kinetic reactor models and feed synthesis
 Project models
– Some contractors have begun to provide Petro-SIM models
– Detailed design models have been built from refinery wide model subflowsheets
– Other models have not been converted due to extensive use of rigorous exchangers
• Awaiting v7 with improved HTRI integration

5. FCC-SIM models to v6.2
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 Have been using v3.2 FCC-SIM models for years
– v4.1 through v6.0 flowsheet based models did not optimize properly
– With double precision reactor modeling, the v6.2 model optimizers worked much better
 Converted all our models to v6.2
– Use meters connected to the PI Historian instead of Excel generated flat files
– Using real plant data as calibration input instead of calculated yields improves the unit
engineer’s understanding of the operating state used for calibration
 KBC Explorer is now used to run predict versus measured cases
– Test the robustness of the model calibration and tuning over time
– Identify plant data issues
– Testing automatic optimization runs

6. LP submodel development
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 FCC-SIM, HXX-SIM and REF-SIM commonly used to update LP submodels
 LP Utility is used to run sets of cases to export to Excel
– Often utilize a spreadsheet operation to capture the results used by the LP Utility
– This keeps the LP Utility results in the order that we want
 The Petro-SIM reactor model results are then used to build the LP model
– Simple step out cases for base delta LP models
– Or, many cases are run for data regressions (linear or non-linear models)

7. Refinery-wide modelling
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 MPC Refinery-wide models
– Use FCC-SIM, HXX-SIM, REF-SIM, CKR-SIM, ISOM, and ALKY reactor models
– Naphtha HT (incl. FCC naph), Sulfolane, RHU, Asphaltene Extraction, etc.
• Custom representations using spreadsheet units or component splitters with custom VB script
 Two additional Refinery-wide models built since last presentation
– Robinson, IL and Catlettsburg, KY
 Both models were built in-house
– Major project team did use KBC consultants to verify some reactor model responses
 Catlettsburg model uses component splitters instead of column models
– Uses shortcut distillation with adjusters to hit product targets
– Much faster than our other refinery-wide models and very robust

8. Crude assays from Spiral Assay
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 Spiral Assay has three options for exporting xml files to be read by Petro-SIM
 Results from the Petro-SIM streams do not match the original assay
 Built a new input dataset within Petro-SIM using Spiral-SDK and Excel
– Transfer three chunks of data: Light ends, Naphtha GC, and Distillate cuts
– Utilizes 49 “Distillate” cuts to match full yield and property curves
 Updated Synthesis settings
– Naphtha modification: Scope = “Modify properties over measured range only”
– Heavy Naphtha / Kerosene range yields match Spiral much better

9. Tips/ Tricks
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 Using Spreadsheet for Logic switches
– Refinery-wide models are simulations: user is required to specify how intermediates
are routed to downstream units
– Our models tend to have flowrate specifications that “flow” backwards through tees
and/or mixers to fill up a process unit to a desired capacity
– Works well until your “incremental” feed runs out or is driven to zero
– Must change flow specifications to allow another feed to be the “incremental” feed
– Another example would be shutting down a portion of the flowsheet
 Spreadsheets can pass “empty” values to flow specifications
– Note: insert/ deleting rows or columns affects “=empty” cells
 Export from Spreadsheets to “Ignore” buttons

10. Tips/ Tricks
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Logic Switches

11. Tips/ Tricks
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Logic Switches

12. Tips/ Tricks
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Spreadsheets for CSTR reactors
 CSTR reactor in Petro-SIM works for chemical applications but not for refining
units with hypothetical components
 Require reactions for properties of components as well
 Made new hypos that matched desired kinetic lumps
 Added user properties to track property lumps
 CSTR reactors are well mixed resulting in the kinetics being driven by the
effluent composition
– Normally requires an iterative approach performed by computer code
– Utilized a recycle block with a spreadsheet unit to handle the calculations
 Used assay adjustors to change the feed into the effluent
– Requires two steps because composition is set by volume so the gravity must be
applied first

13. Tips/ Tricks
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Spreadsheets for CSTR reactors
 The recycle stream gives the basis to calculate the reaction rates
 The feed stream is modified accordingly to become the effluent stream
 The recycle stream is updated and the process repeats

14. Tips/ Tricks
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User Code
 VB Script code can be added to a User Variable
 Can pull in other User Variables or data from the object as input
– X0 = getuservariable(“X”).variable
– Note: user variables are global and must have unique names
 Can export results to the object
 Select a variable in the flowsheet, right-click and “Send details to clipboard” to
see the name to use in the code to link to that variable
– Set mbd = MyBackDoor
– NBP = mbd.BackDoorVariable(“:Temperature.503.1”).Variable.GetValue(“F”)
– Mbd.BackDoorVariable(“:MoleFraction.503.0.0”).Variable.Value = 1

15. Summary
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 MPC is using Petro-SIM reactor models and flowsheets in many areas
– Technical Service process models
– Detailed project models
– LP Submodel development
– Refinery-wide simulation models
– Kinetic model benchmarking
 User properties, script properties, user variables, and user code give sufficient
flexibility to model anything we need