1 - 04/11/23
Departm
ent of Chem
ical E
ngineering
Professor De Chen
Institutt for kjemisk prosessteknologi, NTNU
Gruppe for katalyse og petrokjemi
Kjemiblokk V, rom 407
2 - 04/11/23
Departm
ent of Chem
ical E
ngineering
Kjemisk reaksjonsteknikkChemical 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: 11:15:13:00Problem solving: Tuseday:16:15-17:00
3 - 04/11/23
Departm
ent of Chem
ical E
ngineering
4 - 04/11/23
Departm
ent of Chem
ical E
ngineering
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.
Kjemisk reaksjonsteknikkChemical Reaction Engineering
5 - 04/11/23
Departm
ent of Chem
ical E
ngineering
Lecture notes will be published on It’s learning after the lecture
(Pensumliste ligger på It’s learningDeles ut på de første forelesningene)
Øvingsopplegget ligger på It’s learningDeles ut på de første forelesningene
6 - 04/11/23
Departm
ent of Chem
ical E
ngineering
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
7 - 04/11/23
Departm
ent of Chem
ical E
ngineering
TKP4110 Chemical Reaction Engineering
Øvingene starter onsdag 26 august kl 1615i K5.Lillebø, Andreas Helland: [email protected]
Stud.ass.:Kristian Selvåg : [email protected]
Øyvind Juvkam Eraker: [email protected]
Emily Ann Melsæther: [email protected]
8 - 04/11/23
Departm
ent of Chem
ical E
ngineering
Lecture 1
Kjemisk reaksjonsteknikk
Chemical Reaction Engineering
1.Industrial reactors
2.Reaction engineering
3.Mass balance
4.Ideal reactors
9 - 04/11/23
Departm
ent of Chem
ical E
ngineering
Steam Cracking (Rafnes)
10 - 04/11/23
Departm
ent of Chem
ical E
ngineering
Batch reactor
11 - 04/11/23
Departm
ent of Chem
ical E
ngineering
Fixed bed reactor
12 - 04/11/23
Departm
ent of Chem
ical E
ngineering
CSTR bioreactor
13 - 04/11/23
Departm
ent of Chem
ical E
ngineering
Artificial leaf, photochemical reactor
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Departm
ent of Chem
ical E
ngineering
Chemical Engineering
Reaction engineering
Mass transfer
Heat transfer
Momentum transfer
15 - 04/11/23
Departm
ent of Chem
ical E
ngineering
16 - 04/11/23
Departm
ent of Chem
ical E
ngineering
Reaction Engineering
Mole Balance Rate Laws Stoichiometry
These topics build upon one another
16
17 - 04/11/23
Departm
ent of Chem
ical E
ngineering Mole Balance
Rate Laws
Stoichiometry
Isothermal Design
Heat Effects
17
No-ideal flow
18 - 04/11/23
Departm
ent of Chem
ical E
ngineering
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
19 - 04/11/23
Departm
ent of Chem
ical E
ngineering
Reaction Engineering
1. Week 34, Aug. 21, chapter 1, Introduction, mole balance, and ideal reactors,
2. Week 34, Aug. 23, chapter2, Conversion and reactor size3. Week 35, Aug. 28, chapter 3, Reaction rates4. Week 35, Aug. 30, chapter 3, Stoichometric numbers5. 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
20 - 04/11/23
Departm
ent of Chem
ical E
ngineering
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.
21 - 04/11/23
Departm
ent of Chem
ical E
ngineering
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. Decomposition CH3CH3 H2 + H2C=CH2
2. Combination N2 + O2 2 NO
3. Isomerization C2H5CH=CH2 CH2=C(CH3)2
21
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Departm
ent of Chem
ical E
ngineering
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 asThe rate of Formation (Generation) of product: rP
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23 - 04/11/23
Departm
ent of Chem
ical E
ngineering
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
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Departm
ent of Chem
ical E
ngineering
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
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Departm
ent of Chem
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ngineering
Reaction RateConsider 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)
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26 - 04/11/23
Departm
ent of Chem
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ngineering
General Mole Balance
time
mole
time
mole
time
mole
time
moledt
dNGFF
jSpeciesof
onAccumulati
RateMolar
jSpeciesof
Generation
RateMolar
outjSpecies
ofRate
FlowMolar
injSpecies
ofRate
FlowMolar
jjjj
0
Fj0 FjGj
System Volume, V
26
27 - 04/11/23
Departm
ent of Chem
ical E
ngineering
General Mole Balance
If spatially uniform
G j rjV
If NOT spatially uniform
2V
rj 2
G j1 rj1V1
G j 2 rj 2V2
1V
rj1
27
28 - 04/11/23
Departm
ent of Chem
ical E
ngineering
General Mole Balance
G j rjiVii1
W
G j lim V 0 n
rjiVii1
n
rjdV
Take limit
28
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Departm
ent of Chem
ical E
ngineering
General Mole Balance
General Mole Balance on System Volume V
In Out Generation Accumulation
FA 0 FA rA dV dNA
dt
FA
0
FAGA
System Volume, V
29
30 - 04/11/23
Departm
ent of Chem
ical E
ngineering
Batch Reactor Mole Balance
FA 0 FA rA dV dNA
dtFA 0 FA 0
dNA
dtrAV
Batch
VrdVr AA Well Mixed
30
31 - 04/11/23
Departm
ent of Chem
ical E
ngineering
Batch Reactor Mole Balance
dt dNA
rAVIntegrating
Time necessary to reduce number of moles of A from NA0 to NA.
when t = 0 NA=NA0
t = t NA=NA
A
A
N
N A
A
Vr
dNt
0
31
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Departm
ent of Chem
ical E
ngineering
Batch Reactor Mole Balance
A
A
N
N A
A
Vr
dNt
0
NA
t32
33 - 04/11/23
Departm
ent of Chem
ical E
ngineering
CSTR Mole Balance
FA 0 FA rA dV dNA
dt
dNA
dt0Steady State
CSTR
33
34 - 04/11/23
Departm
ent of Chem
ical E
ngineering
FA 0 FA rAV 0
V FA 0 FA
rA
VrdVr AA Well Mixed
CSTR volume necessary to reduce the molar flow rate from FA0 to FA.
CSTR Mole Balance
34
35 - 04/11/23
Departm
ent of Chem
ical E
ngineering
Plug Flow Reactor Mole Balance
V
V VV
FA
FA
0
0
VrFF
Vin
Generation
VVat
Out
Vat
In
AVVAVA35
36 - 04/11/23
Departm
ent of Chem
ical E
ngineering
limV 0
FA V V FA V
VrA
Rearrange and take limit as ΔV0
dFA
dVrA
Plug Flow Reactor Mole Balance
36
This is the volume necessary to reduce the entering molar flow rate (mol/s) from FA0 to the exit molar flow rate of FA.
37 - 04/11/23
Departm
ent of Chem
ical E
ngineering
Alternative Derivation – Plug Flow Reactor Mole Balance
0 0 dVrFF AAA
0dt
dN ASteady State
dt
dNdVrFF A
AAA 0
PFR
37
38 - 04/11/23
Departm
ent of Chem
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ngineering
dFA
dVrA
0 dFA
dV rA
Differientiate with respect to V
A
A
F
F A
A
r
dFV
0
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.
Alternative Derivation –Plug Flow Reactor Mole Balance
38
39 - 04/11/23
Departm
ent of Chem
ical E
ngineering
dt
dNWrWWFWF A
AAA
AWAWWA
Wr
W
FF
0lim
0dt
dN ASteady State
PBR
Packed Bed Reactor Mole Balance
39
40 - 04/11/23
Departm
ent of Chem
ical E
ngineering
Packed Bed Reactor Mole Balance
dFA
dW r A
Rearrange:
PBR catalyst weight necessary to reduce the entering molar flow rate FA0 to molar flow rate FA.
A
A
F
F A
A
r
dFW
0
The integral form to find the catalyst weight is:
40
41 - 04/11/23
Departm
ent of Chem
ical E
ngineering
Reactor Mole Balance Summary
Reactor Differential Algebraic Integral
V FA 0 FA
rA
CSTR
Vrdt
dNA
A 0
A
A
N
N A
A
Vr
dNtBatch
NA
t
dFA
dVrA
A
A
F
F A
A
dr
dFV
0
PFR
FA
V41