1 - 08/12/2015 Department of Chemical Engineering Lecture 5 Kjemisk reaksjonsteknikk Chemical Reaction Engineering  Isothermal reaction design algorithm  Algorithm to estimate the time or conversion for different reactor  Examples

2 - 08/12/2015 Department of Chemical Engineering These topics build upon one another Mole BalanceRate LawsStoichiometry Reaction Engineering 2 Isothermal reactor design

3 - 08/12/2015 Department of Chemical Engineering For Gas Phase Flow Systems C j =f(F j, T, P) =f(x, T,P) ν j stochiomentric number, b/a, c/a, d/a Isothermal T=T 0 Liquid phase: ε=0

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7 - 08/12/2015 Department of Chemical Engineering Batch reactor 1) Mole balance 2) Rate law X t First-order Second-order 3) Stoichiometry: 4) Combine: 5. Evaluation

8 - 08/12/2015 Department of Chemical Engineering CSTR reactor 1) Mole balance 2) Rate law First-order Second-order 3) Stoichiometry: 4) Combine: 5. Evaluation

9 - 08/12/2015 Department of Chemical Engineering PFR reactor 1) Mole balance 2) Rate law First-order Second-order 3) Stoichiometry: 4) Combine: 5. Evaluation

/12/2015 Department of Chemical Engineering  Examples: Liquid Phase Laboratory Experiment (CH 2 CO) 2 O + H 2 O  2CH 3 COOH A + B  2C Entering Volumetric flow rate v 0 = dm 3 /s Acetic Anhydride7.8% (1M) Water92.2% (51.2M) Elementary with k’1.95x10 -4 dm 3 /(mol.s) Case I CSTRV = 1dm 3 Case II PFRV = dm 3 10

/12/2015 Department of Chemical Engineering Part 1: Mole Balances in Terms of Conversion Algorithm for Isothermal Reactor Design 1. Mole Balance and Design Equation 2. Rate Law 3. Stoichiometry 4. Combine 5. Evaluate A. Graphically (Chapter 2 plots) B. Numerical (Quadrature Formulas Chapter 2 and appendices) C. Analytical (Integral Tables in Appendix) D. Software Packages (Appendix- Polymath) 11

/12/2015 Department of Chemical Engineering CSTR Laboratory Experiment Example: CH 3 CO 2 + H 2 0  2CH 3 OOH 1) Mole Balance: CSTR: 12 A + B  2C

/12/2015 Department of Chemical Engineering 1) Rate Law: 1) Stoichiometry: BF A0 Θ B -F A0 XF B =F A0 (Θ B -X) AF A0 -F A0 XF A =F A0 (1-X) C02F A0 XF C =2F A0 X CSTR Laboratory Experiment 13

/12/2015 Department of Chemical Engineering CSTR Laboratory Experiment 14

/12/2015 Department of Chemical Engineering CSTR Laboratory Experiment 15 V   0 kC A0 XC A 0 1  X    V  0  X 1  X    V  0  kX 1  X  k

/12/2015 Department of Chemical Engineering PFR Laboratory Experiment 1) Mole Balance: 2) Rate Law: 3) Stoichiometry: 16 A + B  2C

/12/2015 Department of Chemical Engineering PFR Laboratory Experiment 4) Combine: 17 4) Combine:

/12/2015 Department of Chemical Engineering  Examples: Gas Phase : PFR and Batch Calculation 2NOCl  2NO + Cl 2 2A  2B + C Pure NOCl fed with C NOCl,0 = 0.2 mol/dm 3 follows an elementary rate law with k = 0.29 dm 3 /(mol.s) Case I PFR withv 0 = 10 dm3/s Find space time, with X = 0.9 Find reactor volume, V for X = 0.9 Case IIBatch constant volume Find the time, t, necessary to achieve 90% conversion. Compare and t. 18

/12/2015 Department of Chemical Engineering Example (Gas Flow, PFR) 2 NOCl  2 NO + Cl 2 1) Mole Balance: 2) Rate Law: 19 2A  2B + C

/12/2015 Department of Chemical Engineering Example (Gas Flow, PFR) 3) Stoich: Gas 4) Combine: A  B + C/2 20 Damköhler number

/12/2015 Department of Chemical Engineering Example (Gas Flow, PFR) 21

/12/2015 Department of Chemical Engineering Example Constant Volume (Batch) 1) Mole Balance: 2) Rate Law: 3) Stoich: Gas 22 Gas Phase 2A  2B + C

/12/2015 Department of Chemical Engineering Example Constant Volume (Batch) 4) Combine: 23