Overview of Process Design

1. Overview of Process Design Chapter 4 Terry A. Ring ChE

2. Where is Design used in Industry?

3. 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 • Decrease Costs • Pollution Minimization

4. 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?

5. How is Design Practiced Stage Gate Management • Process Conception • Preliminary Design • 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

6. 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 • VLE data, solubilities, etc. • Chemical Prices (Chemical Market Reporter)

7. 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)

8. Process Economics-I • 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 • C2H2 + 2HCl + ½ O2 C2H4Cl2+ H2O • 2 C2H4Cl2 2C2H3Cl + 2HCl • 2C2H4 + Cl2 + ½ O2 2C2H3Cl + H2O (overall)

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

10. 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

11. 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

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

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

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

15. Process Synthesis-1 • Separation System

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

17. Onion Model of Process Design

18. Overall Process

19. Octane Reaction • 2C2H4 + C4H10 C8H18 • P= 5 psi, T=93C, X=98% Conversion

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