Transcript Lecture 1
Professor De Chen Institutt for kjemisk prosessteknologi, NTNU Gruppe for katalyse og petrokjemi Department of Chemical Engineering Kjemiblokk V, rom 407 [email protected] 1 - 13/04/2015 Kjemisk reaksjonsteknikk Chemical Reaction Engineering H. Scott Fogler: Elements of Chemical Engineering www.engin.umich.edu/~cre University of Michigan, USA Department of Chemical Engineering Time plan: Week 34-47, Tuesday: 08:15-10:00 Thursday: 11:15:13:00 Problem solving: Tuseday:16:15-17:00 2 - 13/04/2015 Department of Chemical Engineering 3 - 13/04/2015 Kjemisk reaksjonsteknikk Chemical 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. Department of Chemical Engineering 4 - 13/04/2015 Lecture notes will be published on It’s learning after the lecture (Pensumliste ligger på It’s learning Deles ut på de første forelesningene) Department of Chemical Engineering Øvingsopplegget ligger på It’s learning Deles ut på de første forelesningene 5 - 13/04/2015 Felleslaboratorium Faglærer: Professor Heinz Preisig For information: It’s learning Introduction lecture: Department of Chemical Engineering Place : in PFI-50001, the lecture room on the top of the building Date: Tuesday 21 of August Time: 12:15 - 14:00 6 - 13/04/2015 TKP4110 Chemical Reaction Engineering Øvingene starter onsdag 26 august kl 1615 i K5. Lillebø, Andreas Helland: [email protected] Stud.ass.: Kristian Selvåg : [email protected] Department of Chemical Engineering Øyvind Juvkam Eraker: [email protected] Emily Ann Melsæther: [email protected] 7 - 13/04/2015 Lecture 1 Kjemisk reaksjonsteknikk Chemical Reaction Engineering Department of Chemical Engineering 1.Industrial reactors 2.Reaction engineering 3.Mass balance 4.Ideal reactors 8 - 13/04/2015 Steam Cracking (Rafnes) Department of Chemical Engineering 9 - 13/04/2015 Batch reactor Department of Chemical Engineering 10 - 13/04/2015 Fixed bed reactor Department of Chemical Engineering 11 - 13/04/2015 CSTR bioreactor Department of Chemical Engineering 12 - 13/04/2015 Artificial leaf, photochemical reactor Department of Chemical Engineering 13 - 13/04/2015 Chemical Engineering Momentum transfer Department of Chemical Engineering Reaction engineering Mass transfer Heat transfer 14 - 13/04/2015 Department of Chemical Engineering 15 - 13/04/2015 Reaction Engineering Mole Balance Rate Laws Stoichiometry Department of Chemical Engineering These topics build upon one another 16 16 - 13/04/2015 No-ideal flow Heat Effects Isothermal Design Stoichiometry Department of Chemical Engineering Rate Laws Mole Balance 17 17 - 13/04/2015 Chemical kinetics and reactor design are at the heart of producing almost all industrial chemicals Department of Chemical Engineering It is primary a knowledge of chemical kinetics and reactor design that distinguishes the chemical engineer from other engineers 18 - 13/04/2015 Reaction Engineering 1. Week 34, Aug. 21, chapter 1, Introduction, mole balance, and ideal Department of Chemical Engineering reactors, 2. Week 34, Aug. 23, chapter2, Conversion and reactor size 3. Week 35, Aug. 28, chapter 3, Reaction rates 4. Week 35, Aug. 30, chapter 3, Stoichometric numbers 5. Week 36, Sept. 4, chapter 4, isothermal reactor design (1) 6. Week 36, Sept. 6, chapter 4, isothermal reactor design (2) 7. Week 37, Sept. 11, chapter 10, catalysis and kinetics (1) 8. Week 37, Sept. 13, chapter 10, catalysis and kinetics (2) 9. Week 38, Sept. 18, chapter 10, catalysis and kinetics (2) 10.Week 38, Sept. 20, chapter 5,7, kinetic modeling (1) 11.Week 39, Sept. 25, chapter 5,7, kinetic modeling (2) 12.Week 39, Sept. 28 chapter 6, multiple reactions (1) 13.Week 40, Oct. 2, chapter 6 multiple reactions (2) 14.Week 40, Oct. 4, summary of chapter 1-7, and 10 19 - 13/04/2015 Reaction Engineering 41 (9/10, 11/10) 8.1 - 8.2 (JPA) 42 (16/10, 18/10) 8.3 – 8.5 (JPA) 43 (23/10, 25/10) 8.6 - 8.7 (JPA) 44 (30/10, 1/11) 45 (6/11, 8/11) 11 (JPA) 11 (JPA) Department of Chemical Engineering 46 (13/11, 15/11) 12.1-12.4 (JPA) 47 (20/11,22/11) 12.5-12.8 (JPA) 50 (Mandag 13/12) Reaktorberegninger for ikke-isoterme systemer. Energibalanser, stasjonær drift. Omsetning ved likevekt. Optimal fødetemperatur. CSTR med varmeeffekter og flere løsninger ved stasjonær drift, ustabilitet. Masseoverføring, ytre diffusjonseffekter i heterogene systemer. Fylte reaktorer (packed beds). Kjernemodellen (shrinking core). Oppløsning av partikler og regenerering av katalysator. Diffusjon og reaksjon i katalysatorpartikler, Thieles modul, effektivitetsfaktor. Masseoverføring og reaksjon i flerfasereaktorer. Oppsummering. Eksamen, kl 0900-1300. 20 - 13/04/2015 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: Department of Chemical Engineering 1. Decomposition 2. Combination 3. Isomerization CH2=C(CH3)2 CH3CH3 H2 + H2C=CH2 N2 + O2 2 NO C2H5CH=CH2 21 21 - 13/04/2015 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: Department of Chemical Engineering 22 The rate of Disappearance of reactant: -rA or as The rate of Formation (Generation) of product: rP 22 - 13/04/2015 Reaction Rate Department of Chemical Engineering Consider the isomerization AB 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 23 - 13/04/2015 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 Department of Chemical Engineering 24 24 - 13/04/2015 Reaction Rate Department of Chemical Engineering Consider species j: 1.rj is the rate of formation of species j per unit volume [e.g. mol/dm3s] 2.rj is a function of concentration, temperature, pressure, and the type of catalyst (if any) 3. rj is independent of the type of reaction system (batch, plug flow, etc.) 4.rj is an algebraic equation, not a differential equation (e.g. = -rA = kCA or -rA = kCA2) 25 25 - 13/04/2015 General Mole Balance System Volume, V Fj0 Department of Chemical Engineering 26 Gj Fj Molar Flow Molar Flow Molar Rate Molar Rate Rate of Rate of Generation Accum ulation Species j in Species j out of Species j of Species j dN j Fj 0 Fj Gj dt m ole m ole m ole m ole tim e tim e tim e tim e 26 - 13/04/2015 General Mole Balance If spatially uniform G j r jV If NOT spatially uniform Department of Chemical Engineering 27 V1 rj1 G j1 rj1V1 V2 rj 2 G j 2 rj 2 V2 27 - 13/04/2015 General Mole Balance W G j rjiVi i1 Take limit n Department of Chemical Engineering Gj rji Vi r dV j i1 lim V 0 n 28 28 - 13/04/2015 General Mole Balance System Volume, V FA0 GA FA Department of Chemical Engineering General Mole Balance on System Volume V In Out Generation FA 0 FA r dV A Accumulation dN A dt 29 29 - 13/04/2015 Batch Reactor Mole Balance Batch FA 0 FA Department of Chemical Engineering 30 dN A rA dV dt FA 0 FA 0 Well Mixed r A dV rAV dNA rAV dt 30 - 13/04/2015 Batch Reactor Mole Balance dN A dt rAV Integrating when t = 0 NA=NA0 t = t NA=NA Department of Chemical Engineering t NA N A0 dN A rAV Time necessary to reduce number of moles of A from NA0 to NA. 31 31 - 13/04/2015 Batch Reactor Mole Balance t NA N A0 Department of Chemical Engineering 32 dN A rAV NA t 32 - 13/04/2015 CSTR Mole Balance CSTR Department of Chemical Engineering dNA FA 0 FA rA dV dt Steady State dNA 0 dt 33 33 - 13/04/2015 CSTR Mole Balance Well Mixed r dV r V A A FA 0 FA rAV 0 Department of Chemical Engineering 34 FA 0 FA V rA CSTR volume necessary to reduce the molar flow rate from FA0 to FA. 34 - 13/04/2015 Plug Flow Reactor Mole Balance V FA FA Department of Chemical Engineering 35 V V V In Out Generation 0 at V at V V in V FA V FA V V rA V 0 35 - 13/04/2015 Plug Flow Reactor Mole Balance Rearrange and take limit as ΔV0 lim V 0 Department of Chemical Engineering 36 FA V V FA V V rA dFA rA dV 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 - 13/04/2015 Alternative Derivation – Plug Flow Reactor Mole Balance PFR dN A FA0 FA rA dV dt Department of Chemical Engineering Steady State dN A 0 dt FA0 FA rA dV 0 37 37 - 13/04/2015 Alternative Derivation – Plug Flow Reactor Mole Balance Differientiate with respect to V dFA 0 rA dV Department of Chemical Engineering 38 The integral form is: dFA rA dV V FA FA 0 dFA rA 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 - 13/04/2015 Packed Bed Reactor Mole Balance PBR Department of Chemical Engineering 39 dN A FA W FA W W rA W dt dN A Steady State 0 dt lim W 0 FA W W FA W W rA 39 - 13/04/2015 Packed Bed Reactor Mole Balance Rearrange: dFA rA dW The integral form to find the catalyst weight is: Department of Chemical Engineering 40 W FA FA 0 dFA rA PBR catalyst weight necessary to reduce the entering molar flow rate FA0 to molar flow rate FA. 40 - 13/04/2015 Reactor Mole Balance Summary Reactor Batch Differential Integral t dN A rAV dt NA N A0 dN A rAV NA t Department of Chemical Engineering FA 0 FA V rA CSTR PFR Algebraic dFA rA dV V FA FA 0 FA dFA drA V 41 41 - 13/04/2015