1. CHE412 Process Dynamics and Control BSc (Engg) Chemical Engineering (7 th Semester) Week 3 (contd.) Mathematical Modeling (Contd.) Luyben (1996) Chapter 3 Stephanopoulos (1984) Chapter 5 Dr Waheed Afzal Associate Professor of Chemical Engineering Institute of Chemical Engineering and Technology University of the Punjab, Lahore wa.icet@pu.edu.pk 1

2. 2 Modeling CSTRs in Series constant holdup, isothermal F0F0 F 1 C A1 F 2 C A2 F 3 C A3 V1K1T1V1K1T1 V2K2T2V2K2T2 V3K3T3V3K3T3 Luyben (1996)

3. 3 Modeling CSTRs in Series constant holdup, isothermal

4. 4

5. 5 Modeling CSTRs in Series Variable Holdups, n th order Changes from previous case: V of reactors (and F) varies with time, reaction is n th order Parameters to be known: k 1, k 2, k 3, n Disturbances to be specified: C A0, F 0 Unknown variables: C A1, C A2, C A3, V 1, V 2, V 3, F 1, F 2, F 3 CVMV Include Controller eqns V 1 (or h 1 )F1F1 F 1 = f(V 1 ) V 2 (or h 2 )F2F2 F 2 = f(V 2 ) V 3 (or h 3 )F3F3 F 3 = f(V 3 )

6. H1H1 H2H2 H3H3 Q in or out 6 Modeling a Mixing Process Basis and Assumptions F (volumetric), C A (molar); Well Stirred Feed (1, 2) consists of components A and B Enthalpy of mixing is significant Process includes heating/ cooling ρ is constant Stephanopoulos (1984)

7. H1H1 H2H2 H3H3 7 Modeling a Mixing Process

8. 8 Put values of h in overall energy balance

9. 9 Modeling a Mixing Process

10. Tips For Assessment (Exam) Introduction + Modeling (week 1-3) 10 1.Consult your class notes, board proofs, discussions 2.Stephanopoulos (1984) chapters 1-5, examples and end-chapter problems 3.Luyben (1996) chapter 3 page 40 to 74. Practice examples and end-chapter problems for chapter 3. In exam, you may be asked short descriptive questions to check your understanding of process control and to prepare a mathematical model for a chemical process or processes and to make the system exactly specified (i.e. N f = 0)

11. Week 3 Weekly Take-Home Assignment 1.Follow all the example modeling exercises in Luyben (1996) chapter 3 page 40 to 74. Practice these example processes. 2.Solve at least 10 end-chapter problems from Luyben (1996) chapter 3 (Compulsory) 11 Submit before Friday (Feb 7) Curriculum and handouts are posted at: http://faculty.waheed-afzal1.pu.edu.pk/