1. Chemical Reaction Engineering Asynchronous Video Series Chapter 4, Part 1: Applying the Algorithm to a CSTR H. Scott Fogler, Ph.D.

2. Summary At the start of the chapter we saw we needed -r A =f(X). This result is achieved in two steps. 1.Rate Laws –-r A =k f(C i ) –1st order A--> B or 1st order –2nd order A+B --> C –Rate laws are found by experiment 2.Stoichiometry –Liquid: –Gas: -r A =kC A -r A =k A C A C B

3. Algorithm for Isothermal Reactor Design 1.Mole Balance and Design Equation 2.Rate Law 3.Stoichiometry 4.Combine 5.Evaluate

4. Algorithm for Isothermal Reactor Design 1.Mole Balance and Design Equation 2.Rate Law 3.Stoichiometry 4.Combine 5.Evaluate The Evaluate step can be carried out:

5. Algorithm for Isothermal Reactor Design 1.Mole Balance and Design Equation 2.Rate Law 3.Stoichiometry 4.Combine 5.Evaluate The Evaluate step can be carried out: 1.Graphically (Chapter 2 plots)

6. Algorithm for Isothermal Reactor Design 1.Mole Balance and Design Equation 2.Rate Law 3.Stoichiometry 4.Combine 5.Evaluate The Evaluate step can be carried out: 1.Graphically (Chapter 2 plots) 2.Numerically (Quadrature formulas: Chapter 2 and Appendices)

7. Algorithm for Isothermal Reactor Design 1.Mole Balance and Design Equation 2.Rate Law 3.Stoichiometry 4.Combine 5.Evaluate The Evaluate step can be carried out: 1.Graphically (Chapter 2 plots) 2.Numerically (Quadrature formulas: Chapter 2 and Appendices) 3.Analytically (Integral tables in Appendix)

8. Algorithm for Isothermal Reactor Design 1.Mole Balance and Design Equation 2.Rate Law 3.Stoichiometry 4.Combine 5.Evaluate The Evaluate step can be carried out: 1.Graphically (Chapter 2 plots) 2.Numerically (Quadrature formulas: Chapter 2 and Appendices) 3.Analytically (Integral tables in Appendix) 4.Software packages (Appendix - Polymath)

9. French Menu Analogy

17. Example: The elementary gas phase reaction takes place in a CSTR at constant temperature (500 K) and constant pressure (16.4 atm). The feed is equal molar in A and B.

18. French Menu Analogy Example: The elementary gas phase reaction takes place in a CSTR at constant temperature (500 K) and constant pressure (16.4 atm). The feed is equal molar in A and B. Mole Balance:

19. French Menu Analogy Example: The elementary gas phase reaction takes place in a CSTR at constant temperature (500 K) and constant pressure (16.4 atm). The feed is equal molar in A and B. Mole Balance: Rate Law:

20. Example: The elementary gas phase reaction takes place in a CSTR at constant temperature (500 K) and constant pressure (16.4 atm). The feed is equal molar in A and B. Mole Balance: Rate Law: Stoichiometry: gas phase, isothermal (T=T 0 ), no pressure drop (P=P 0 ) French Menu Analogy

21. Remember the French Menu reaction: For a gas phase system: Deriving C A and C B :

22. French Menu Analogy Remember the French Menu reaction: For a gas phase system: If the conditions are isothermal (T = T 0 ) and isobaric (P =P 0 ): Deriving C A and C B :

23. French Menu Analogy Remember the French Menu reaction: For a gas phase system: If the conditions are isothermal (T = T 0 ) and isobaric (P =P 0 ): We must divide by the stoichiometric coefficient of our basis of calculation yielding: Deriving C A and C B :

24. French Menu Analogy Remember the French Menu reaction: For a gas phase system: If the conditions are isothermal (T = T 0 ) and isobaric (P =P 0 ): We must divide by the stoichiometric coefficient of our basis of calculation yielding: And if the feed is equal molar, then: Deriving C A and C B :

25. French Menu Analogy This leaves us with C A as a function of conversion alone: Deriving C A and C B :

26. French Menu Analogy This leaves us with C A as a function of conversion alone: Similarly for C B : Deriving C A and C B :

27. Example: The elementary gas phase reaction takes place in a CSTR at constant temperature (500 K) and constant pressure (16.4 atm). The feed is equal molar in A and B. Mole Balance: Rate Law: Stoichiometry: gas phase, isothermal (T=T 0 ), no pressure drop (P=P 0 ) [Why do you think C B is constant, when B is consumed?] French Menu Analogy

28. Example: The elementary gas phase reaction takes place in a CSTR at constant temperature (500 K) and constant pressure (16.4 atm). The feed is equal molar in A and B. Mole Balance: Rate Law: Stoichiometry: gas phase, isothermal (T=T 0 ), no pressure drop (P=P 0 ) [Why do you think C B is constant, when B is consumed?] French Menu Analogy

29. Example: The elementary gas phase reaction takes place in a CSTR at constant temperature (500 K) and constant pressure (16.4 atm). The feed is equal molar in A and B. Mole Balance: Rate Law: Stoichiometry: gas phase, isothermal (T=T 0 ), no pressure drop (P=P 0 ) [Why do you think C B is constant, when B is consumed?] Combine: French Menu Analogy

30. Example: The elementary gas phase reaction takes place in a CSTR at constant temperature (500 K) and constant pressure (16.4 atm). The feed is equal molar in A and B. Mole Balance: Rate Law: Stoichiometry: gas phase, isothermal (T=T 0 ), no pressure drop (P=P 0 ) [Why do you think C B is constant, when B is consumed?] Combine: Evaluate: French Menu Analogy