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Professor De Chen Institutt for kjemisk prosessteknologi, NTNU Gruppe for katalyse og petrokjemi

Professor De Chen Institutt for kjemisk prosessteknologi, NTNU Gruppe for katalyse og petrokjemi Kjemiblokk V, rom 407 chen@nt.ntnu.no. Kjemisk reaksjonsteknikk Chemical Reaction Engineering H. Scott Fogler: Elements of Chemical Engineering www.engin.umich.edu/~cre

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Professor De Chen Institutt for kjemisk prosessteknologi, NTNU Gruppe for katalyse og petrokjemi

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  1. Professor De Chen Institutt for kjemisk prosessteknologi, NTNU Gruppe for katalyse og petrokjemi Kjemiblokk V, rom 407 chen@nt.ntnu.no

  2. Kjemisk reaksjonsteknikk Chemical Reaction Engineering H. Scott Fogler: Elements of Chemical Engineering www.engin.umich.edu/~cre University of Michigan, USA Time plan: Week 34-47, Tuesday: 08:15-10:00 Thursday: 11:15:13:00 Problem solving: Tuseday:16:15-17:00

  3. Kjemisk reaksjonsteknikkChemical Reaction Engineering • 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.

  4. Lecture notes will be published on It’s learning after the lecture (Pensumliste ligger på It’s learning Deles ut på de første forelesningene) Øvingsopplegget ligger på It’s learning Deles ut på de første forelesningene

  5. Felleslaboratorium Faglærer: Professor Heinz Preisig For information: It’s learning Introduction lecture: Place :  in PFI-50001, the lecture room on the top of the buildingDate:    Tuesday 21 of AugustTime:    12:15 - 14:00

  6. TKP4110 Chemical Reaction Engineering Øvingene starter onsdag 26 august kl 1615 i K5. Lillebø, Andreas Helland:andreas.lillebo@chemeng.ntnu.no Stud.ass.: Kristian Selvåg : krisse@stud.ntnu.noØyvind Juvkam Eraker: oyvindju@stud.ntnu.noEmily Ann Melsæther:  melsathe@stud.ntnu.no

  7. Lecture 1 Kjemisk reaksjonsteknikk Chemical Reaction Engineering • Industrial reactors • Reaction engineering • Mass balance • Ideal reactors

  8. Steam Cracking (Rafnes)

  9. Batch reactor

  10. Fixed bed reactor

  11. CSTR bioreactor

  12. Artificial leaf, photochemical reactor

  13. Chemical Engineering Momentum transfer Reaction engineering Mass transfer Heat transfer

  14. Reaction Engineering Mole Balance Stoichiometry Rate Laws These topics build upon one another 16

  15. No-ideal flow Heat Effects Isothermal Design Stoichiometry Rate Laws Mole Balance 17

  16. Chemical kinetics and reactor design are at the heart of producing almost all industrial chemicals It is primary a knowledge of chemical kinetics and reactor design that distinguishes the chemical engineer from other engineers

  17. Reaction Engineering • Week 34, Aug. 21, chapter 1, Introduction, mole balance, and ideal reactors, • Week 34, Aug. 23, chapter2, Conversion and reactor size • Week 35, Aug. 28, chapter 3, Reaction rates • Week 35, Aug. 30, chapter 3, Stoichometric numbers • Week 36, Sept. 4, chapter 4, isothermal reactor design (1) • Week 36, Sept. 6, chapter 4, isothermal reactor design (2) • Week 37, Sept. 11, chapter 10, catalysis and kinetics (1) • Week 37, Sept. 13, chapter 10, catalysis and kinetics (2) • Week 38, Sept. 18, chapter 10, catalysis and kinetics (2) • Week 38, Sept. 20, chapter 5,7, kinetic modeling (1) • Week 39, Sept. 25, chapter 5,7, kinetic modeling (2) • Week 39, Sept. 28 chapter 6, multiple reactions (1) • Week 40, Oct. 2, chapter 6 multiple reactions (2) • Week 40, Oct. 4, summary of chapter 1-7, and 10

  18. Reaction Engineering • 41 (9/10, 11/10) 8.1 - 8.2 (JPA) Reaktorberegninger for ikke-isoterme systemer. • 42 (16/10, 18/10) 8.3 – 8.5 (JPA) Energibalanser, stasjonær drift. Omsetning ved likevekt. Optimal fødetemperatur. • 43 (23/10, 25/10) 8.6 - 8.7 (JPA) CSTR med varmeeffekter og flere løsninger ved stasjonær drift, ustabilitet. • 44 (30/10, 1/11) 11 (JPA) Masseoverføring, ytre diffusjonseffekter i heterogene systemer. • 45 (6/11, 8/11) 11 (JPA) Fylte reaktorer (packed beds). Kjernemodellen (shrinking core). Oppløsning av partikler og regenerering av katalysator. • 46 (13/11, 15/11) 12.1-12.4 (JPA) Diffusjon og reaksjon i katalysatorpartikler, Thieles modul, effektivitetsfaktor. • 47 (20/11,22/11) 12.5-12.8 (JPA) Masseoverføring og reaksjon i flerfasereaktorer. Oppsummering. • 50 (Mandag 13/12) Eksamen, kl 0900-1300.

  19. Chemical Identity and reaction A chemical species is said to have reacted when it has lost its chemical identity. There are three ways for a species to loose its identity: 1. DecompositionCH3CH3 H2 + H2C=CH2 2. Combination N2 + O2 2 NO 3. Isomerization C2H5CH=CH2 CH2=C(CH3)2 21

  20. Reaction Rate The reaction rate is the rate at which a species looses its chemical identity per unit volume. The rate of a reaction (mol/dm3/s) can be expressed as either: The rate of Disappearance of reactant: -rA or as The rate of Formation (Generation) of product: rP 22

  21. Reaction Rate Consider the isomerization A  B rA = the rate of formation of species A per unit volume -rA = the rate of a disappearance of species A per unit volume rB = the rate of formation of species B per unit volume 23

  22. Reaction Rate For a catalytic reaction, we refer to -rA', which is the rate of disappearance of species A on a per mass of catalyst basis. (mol/gcat/s) NOTE: dCA/dt is not the rate of reaction 24

  23. Reaction Rate Consider species j: rj is the rate of formation of species j per unit volume [e.g. mol/dm3s] rj is a function of concentration, temperature, pressure, and the type of catalyst (if any) rj is independent of the type of reaction system (batch, plug flow, etc.) rj is an algebraic equation, not a differential equation (e.g. = -rA = kCA or -rA = kCA2) 25

  24. General Mole Balance System Volume, V Fj0 Fj Gj 26

  25. General Mole Balance If spatially uniform If NOT spatially uniform 27

  26. General Mole Balance Take limit 28

  27. General Mole Balance General Mole Balance on System Volume V System Volume, V FA0 FA GA 29

  28. Batch Reactor Mole Balance Batch Well Mixed 30

  29. Batch Reactor Mole Balance when t = 0 NA=NA0 t = t NA=NA Integrating Time necessary to reduce number of moles of A from NA0 to NA. 31

  30. Batch Reactor Mole Balance NA t 32

  31. CSTR Mole Balance CSTR Steady State 33

  32. CSTR Mole Balance Well Mixed CSTR volume necessary to reduce the molar flow rate from FA0 to FA. 34

  33. Plug Flow Reactor Mole Balance 35

  34. Plug Flow Reactor Mole Balance Rearrange and take limit as ΔV0 This is the volume necessary to reduce the entering molar flow rate (mol/s) from FA0 to the exit molar flow rate of FA. 36

  35. Alternative Derivation – Plug Flow Reactor Mole Balance PFR Steady State 37

  36. Alternative Derivation –Plug Flow Reactor Mole Balance Differientiate with respect to V The integral form is: This is the volume necessary to reduce the entering molar flow rate (mol/s) from FA0 to the exit molar flow rate of FA. 38

  37. Packed Bed Reactor Mole Balance PBR Steady State 39

  38. Packed Bed Reactor Mole Balance Rearrange: The integral form to find the catalyst weight is: PBR catalyst weight necessary to reduce the entering molar flow rate FA0 to molar flow rate FA. 40

  39. Reactor Mole Balance Summary NA FA V t Batch CSTR PFR 41

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