Molecular Level Description of Crude Oils and Complex Hydrocarbon Streams

1. Molecular Level Description of Crude Oils and Complex Hydrocarbon Streams Lanny Carr – Invensys Process System REFINING CHINA 2006 April 24 -26 Beijing, China

2. What if… • …we could remove the uncertainty about using old assay data as the basis for how we process today’s feedstocks? • …we could reduce inherent assay errors by using measurements that we can take at the plant site? • …we could make those corrections on a daily basis? • …we could produce deeper information about true compositional nature of feedstocks and other process streams? • …we could use that detailed knowledge as more accurate input to planning and optimization tools for daily operational improvements? • …what if?

3. Assays - What they are… • Laboratory measurements of distillation yield behavior. • A convenient way to lump crude oil into a manageable number of pseudocomponents. • Laboratory measurements of properties of these pseudocomponents. • Source of data for API correlations. • Source of data for Linear and Simulation Programs.

4. Assays - the Problems... • High quality assays are costly and time-consuming to produce. • Library assays go out-of-date as fields mature. • Input data used to select assays are often just bulk properties that are insensitive to distributed properties. • Blending during gathering and transportation can create compositional characteristics difficult to mimic with available assays. • Even perfect assays can fail, for fundamental reasons, to fully account for compositional differences that govern the refining outcome.

5. Issues when Evaluating Quality • Crude oil quality is difficult to measure. • Analytical measurements contain error. • Need to rely on data of unknown quality. • ‘Typical’ assays are commonly used in place of ‘measured’ assays. • Bulk property correlations contain deviations and are insensitive to important compositional variations. • LP models and simulators don’t always agree with the refinery operation.

6. [Z-BaSICtm] Method The Z - Based Structural Index Correlation All compounds in crude oil are classified according to the general empirical formula: CnH2n+zNuSvOw… • z-vectors are the classifying numbers • ‘n’ is the primary correlating variable

7. Crude Oil Composition - Simplified • All crudes are made up of a few dozen classes of compounds. • Each class has a mass distribution with respect to molecular weight. • Each class and molecular weight set are comprised of multiple isomers. In short, crude oil may be described by mass distributions with respect to 3 independent variables, ‘z’, ‘n’ and ‘i’.

8. Refinery Operations - Simplified Refining operations are processes to: • alter the classes (hydrogenation, reforming, HDS, HDN, etc.) • alter the molecular weight (FCC, HC, alkylation, coking, etc.) • alter the isomer structure (isomerization, cat. dewaxing, etc.) In Short, refining alters the ‘z’, ‘n’, and ‘i’ character of crude oil.

9. Correlation of Boiling Point with ‘n’ and ‘z’

10. Correlation of density with ‘n’ and ‘z’

11. Density vs Carbon Number

12. C16-C17 excerpt

13. Jet A Property Variations

14. Jet A Heating Value at Constant Density

15. Jet A Aromatics vs. Paraffins at Constant Density.

16. Speciation with Molecular Modeling

17. 1,800 Heavy Naphtha 1,600 Light Naphtha 1,400 LGO RC KERO HGO TBP Temperature, deg. F 1,200 1,000 800 600 400 200 0 0 10 20 30 40 50 60 70 80 90 100 Liquid Volume Percent, LV% NL Planner System (Assay） ROMeo Non Linear Planner LPG LPG LN LN 51 Pure-components Old System Cut-Point Base (Pseudo Component) HN HN KERO KERO LGO LGO 39 High Fidelity Pseudo-Components HGO HGO RC RC

18. Grouping of Hi Fidelity Pseudocomponents

19. Heavy Naphtha Cut at Constant Density

20. Crude Assay Data Compensation Method ROMeo Online Model Z-Basic Blend Crudes & generate pure components & high fidelity pseudo-components Update individual crude ASSAYS from online measurements & lab data Data Reconciliation PerformanceMonitoring Assay C4 C12 Component Estimation Crude Assay Library

21. Data Inputs & Outputs • NMR provides additional information for the Z-BaSIC convergence • Total Hydrogen • A, O, S Hydrogen • Sulfur

22. Interface with Conventional Systems Conventional Assays Pseudocomponents ________________ LP Sim Opt Crude Oil or Monitors Reference file Pure components + Hi Fidelity Pseudocomponents ___________________ Props, Comp, Sim, Opt

23. Speciated Stream Preparation and Analysis Reconciled Assay NL Planner /ROMeo Pseudo Components Plus Distinct Species Each Pseudo-Component Weight % Species + Properties Weight % HC minus Species + Properties

24. …What can we do with Speciation? Yield1 & Properties + Components Simulated Unit Yield2 & Properties + Components Yield3 & Properties + Components Yield4 & Properties + Components Yield5 & Properties + Components

25. Price & Constraint Visibility Role Activity Technology Refinery Planner Develop Operating Plan Refinery NLP or LP Update qualities Schedule Refinery Schedule Lost Opportunity Refinery Scheduler Process Unit Detailed Targets Daily Crude Mix Daily Liftings Prices Set Process Unit Detailed Targets Daily Targets with Refinery Wide Representation Operations Manager Approved Targets Constraints Operator Process Unit Targets with Refinery Wide Representation Set Operating Limits Set points APC Targets

26. Molecular Modeling - Advantages • Overcomes limitations of existing crude oil assay technology • Enables crude oil analysis on a fundamental molecular level • Potential benefits in excess of $0.30/bbl • Moves technology to a more scientific basis for component speciation