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Overview of Process Design

Overview of Process Design. Chapter 7 Sieder, et.al. Terry A. Ring ChE. Where is Design used in Industry?. De Novo Designs Known Plants but different location or larger size Plant Improvement Debottlenecking Plant Increase Plant Capacity Increase Plant Efficiency

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Overview of Process Design

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  1. Overview of Process Design Chapter 7 Sieder, et.al. Terry A. Ring ChE

  2. Where is Design used in Industry? • De Novo Designs • Known Plants but different location or larger size • Plant Improvement • Debottlenecking Plant • Increase Plant Capacity • Increase Plant Efficiency • Raw Material Substitution • Decrease Costs • Pollution Minimization

  3. Importance of Process Design • In Preliminary Process Design • 98% Operating Costs Committed • 80% Capital Costs Committed • Less than 10% $ Spent • Design is Very Important • But why is this so?

  4. How is Design Practiced Stage Gate Management • Process Conception • Simple Economics • Preliminary Design (CAPEX±20%) • Process Concepts • Process Economics • Management decision to go forward • Intermediate Design • P&ID’s • Ask vendors for prices major pieces of equipment • Reactor, Separators, HX, Utilities, tank farms • Process Economics • Management decision to go forward • Detailed Design • Mechanical Engineering • Equipment + Supports • Where are all the nuts and bolts • Piping elevation • Electrical/Power Engineering • Utilities • Process Economics • Management decision to go forward

  5. Process Creation • Chemical Reaction Routes • Preliminary Database • MSDS – (Health and safety info.) • Raw Materials • Reaction Products and Intermediates • Thermo/phys properties (Expts and Predictions) • Heats of Formation, heat capacities • VLE data, solubilities, etc. • Chemical Prices (Chemical Market Reporter)

  6. Operating costs • Selection of Raw Materials • Selection of Reaction Path to Product • Determine Gross Profitability of Process • Examples • Vinyl Chloride Manufacture (part of PVC plant) • Example in your book • Octane Manufacture (part of refinery)

  7. Process Economics-101 • Macro View • Possible Reactions for vinyl chloride • 1) C2H4 (ethylene) + Cl2 C2H3Cl (vinyl Chloride) + HCl • 2) C2H2 (acetylene) + HCl  C2H3Cl • 3) C2H4 + Cl2 C2H4Cl2  C2H3Cl + HCl • 4) C2H2 + 2HCl + ½ O2 C2H4Cl2+H2O • C2H4Cl2 C2H3Cl +H2O • C2H2 + 2HCl + ½ O2C2H3Cl +H2O (overall) • 5) C2H4 + Cl2 C2H4Cl2 Chlorination • C2H2 + 2HCl + ½ O2 C2H4Cl2+ H2O • 2 C2H4Cl2 2C2H3Cl + 2HCl Pyrolysis • 2C2H4 + Cl2 + ½ O2 2C2H3Cl + H2O (overall)

  8. Gross Profitability Analysis-1 • Start With Raw Material Costs and Product Prices

  9. Gross Profitability Analysis-1 • For Each Reaction Determine the Profit to be made • Gross Profit is • 22¢/lb(1) +18¢/lb (0.583)-18¢/lb(0.449)-11¢/lb(1.134)=11.94 ¢/lb

  10. Gross Profitability Analysis-2 • Overview of Various Reactions • Reaction 3 is most profitable! • How much do we make? Market Volume? http://nexant.ecnext.com/coms2/summary_0255-3041_ITM

  11. Example of Market Information http://www.ceramics.org/ASSETS/574195312DA149928805FFEA1242FECF/MaterialsReview_08_08.pdf

  12. Process Synthesis-1 • Reaction 3 • Direct Chlorination • Pyrolysis

  13. Consider Separations • VLE data • Boiling Points • Flash HCl from Rxn Products

  14. Process Synthesis-1 • Separation System

  15. Process Synthesis-3 • Task Integration • Reactor & Condenser • Separations

  16. Onion Model of Process Design

  17. Overall Process

  18. Octane Reaction • 2C2H4 + C4H10 C8H18 • P= 5 psi, T=93C, X=98% Conversion • How do you know this?

  19. 1) Free Energy, ΔG, calc. 2) Optimize Gibbs Reactor

  20. Preliminary Flow Sheet Flash ΔP= 2 psi Distillation Purge Stream

  21. With Heat Integration Without Heat Integration

  22. What else can be done? • Where is the heat duty for the Flash vessel coming from? • Heat Exchanger coupling reactor feed to reactor product. • Do we really need the flash vessel? • Let distillation column do all the separation. • Reactor heat duty • Exo or Endo reaction? • Where does it come from?

  23. Onion Model of Process Design

  24. Importance of Process Design • In Preliminary Process Design • 98% Operating Costs Committed • 80% Capital Costs Committed • Less than 10% $ Spent • Design is Very Important • But why is this so?

  25. Why • In Preliminary Design • Decide on Raw Materials Operating Costs • Decide Process • Reactor System Capital Costs • Separation System Capital Costs • Recycle System Capital Costs • Heat Integration Scheme Capital Costs • Utilities Operating Costs

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