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
Detailed Design
Mechanical Engineering
Equipment + Supports
Where are all the nuts and bolts
Piping elevation
Electrical/Power Engineering
Utilities

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?

12. Example of Market Information

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