1. Chemical Reaction Engineering (CRE) is the field that studies the rates and mechanisms of chemical reactions and the design of the reactors in which they take place. Lecture 2 1

2. Today’s lecture Review of Lecture 1 Solution to P1-6 Definition of Conversion, X Develop the Design Equations in Terms of X Size CSTRs and PFRs given –r A = f(X) Conversion for Reactors in Series Review the Fall of the Tower of CRE 2

3. Reactor Mole Balance Summary ReactorDifferentialAlgebraicIntegral CSTR Batch NANA t PFR FAFA V 3

4. Homework Problem Solution 4 Liquid phase Given the following information, Find V

5. (1) Mole Balance: (2) Rate Law: (3) Stoichiometry: 5

6. (4) Combine: (5) Evaluate: 6

7. Consider the generic reaction 7

8. Batch 8

9. Integrating The necessary t to achieve conversion X. 9

10. CSTR Steady State 10

11. Well Mixed CSTR CSTR volume necessary to achieve conversion X. 11

12. Steady State PFR 12

13. This is the PFR volume necessary to achieve conversion X. PFR Integrating 13

14. Reactor Mole Balances in terms of conversion ReactorDifferentialAlgebraicIntegral CSTR PFR Batch X t PBR X W 14

15. Levenspiel Plots Reactor Sizing Given –r A as a function of conversion, -r A = f(X), one can size any type of reactor. We do this by constructing a Levenspiel plot. Here we plot either (F A0 /-r A ) or (1/-r A ) as a function of X. For (F A0 /-r A ) vs. X, the volume of a CSTR and the volume of a PFR can be represented as the shaded areas in the Levenspiel Plots shown as: 15

16. Levenspiel Plots 16

17. Numerical Evaluations of Integrals The integral to calculate the PFR volume can be evaluated using method as Simpson’s One-Third Rule: (See Appendix A.4) Other numerical methods are: Trapezoidal Rule (uses two data points) Simpson’s Three-Eight’s Rule (uses four data points) Five-Point Quadrature Formula 17

18. Reactors in Series Given: r A as a function of conversion, one can also design any sequence of reactors: Only valid if there are no side streams. Molecule Flow rate of species A at point i: 18

19. Reactors in Series 19

20. Reactors in Series Reactor 1: 20 V1V1

21. Reactors in Series Reactor 2: 21 V2V2

22. Reactors in Series Reactor 3: 22 V3V3

23. Reactors in Series 23

24. Reactors in Series Space time τ is the time necessary to process 1 reactor volume of fluid at entrance conditions. 24

25. KEEPING UP The tower of CRE, is it stable? 25

26. Reaction Engineering These topics build upon one another Mole BalanceRate LawsStoichiometry 26

27. Mole Balance Rate Laws Stoichiometry Isothermal Design Heat Effects 27

28. Mole Balance Rate Laws 28

29. Mole Balance Rate Laws Stoichiometry Isothermal Design Heat Effects 29

30. End of Lecture 2 30