Download - Lecture 1
![Page 1: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/1.jpg)
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.
Lecture 1
1
![Page 2: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/2.jpg)
Today’s lecture Introduction Definitions General Mole Balance Equation
Batch (BR) Continuously Stirred Tank Reactor
(CSTR) Plug Flow Reactor (PFR) Packed Bed Reactor (PBR)
2
![Page 3: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/3.jpg)
Chemical Reaction EngineeringChemical reaction engineering is at the heart of virtually every chemical process. It separates the chemical engineer from other engineers.Industries that Draw Heavily on Chemical Reaction Engineering (CRE) are:
CPI (Chemical Process Industries)Examples like Dow, DuPont, Amoco,
Chevron
3
![Page 4: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/4.jpg)
4
![Page 5: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/5.jpg)
Chemical Plant for Ethylene Glycol (Ch. 5)
Smog (Ch. 1)
Plant Safety(Ch.
11,12,13)
Lubricant Design (Ch.
9)
Cobra Bites (Ch. 6 DVD-
ROM)
Oil Recovery (Ch. 7)
Wetlands (Ch. 7 DVD-ROM)
Hippo Digestion (Ch. 2)
5
![Page 6: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/6.jpg)
http://www.umich.edu/~ess
en/
Materials on the Web and CD-ROM
6
![Page 7: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/7.jpg)
Let’s Begin CREChemical 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.
7
![Page 8: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/8.jpg)
Chemical IdentityA chemical species is said to have reacted
when it has lost its chemical identity.The identity of a chemical species is
determined by the kind, number, and configuration of that species’ atoms.
8
![Page 9: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/9.jpg)
Chemical IdentityA 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 NO3. Isomerization C2H5CH=CH2
CH2=C(CH3)2
9
![Page 10: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/10.jpg)
Reaction RateThe 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
10
![Page 11: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/11.jpg)
Reaction RateConsider the isomerization
A BrA = 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
11
![Page 12: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/12.jpg)
Reaction RateEXAMPLE: AB
If Species B is being formed at a rate of 0.2 moles per decimeter cubed per second, ie, rB = 0.2 mole/dm3/s
Then A is disappearing at the same rate:-rA= 0.2 mole/dm3/s
The rate of formation (generation of A) is rA= -0.2 mole/dm3/s
12
![Page 13: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/13.jpg)
Reaction RateFor 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
13
![Page 14: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/14.jpg)
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 = kCA
2)14
![Page 15: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/15.jpg)
General Mole Balance
timemole
timemole
timemole
timemole
dtdN
GFF
jSpeciesofonAccumulati
RateMolar
jSpeciesofGeneration
RateMolar
outjSpeciesofRate
FlowMolar
injSpeciesofRate
FlowMolar
jjjj
0
Fj0 FjGj
System Volume, V
15
![Page 16: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/16.jpg)
General Mole BalanceIf spatially uniform
G j rjV
If NOT spatially uniform
2V
rj 2
G j1 rj1V1
G j 2 rj 2V2
1V
rj1
16
![Page 17: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/17.jpg)
General Mole Balance
G j rjiVii1
W
G j lim V 0 n
rjiVii1
n
rjdV
Take limit
17
![Page 18: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/18.jpg)
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
18
![Page 19: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/19.jpg)
Batch Reactor Mole Balance
FA 0 FA rA dV dNA
dtFA 0 FA 0
dNA
dtrAV
Batch
VrdVr AA Well Mixed
19
![Page 20: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/20.jpg)
Batch Reactor Mole Balance
dt dNA
rAVIntegrating
Time necessary to reduce number of moles of A from NA0 to NA.
when t = 0 NA=NA0t = t NA=NA
A
A
N
N A
A
VrdNt
0
20
![Page 21: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/21.jpg)
Batch Reactor Mole Balance
A
A
N
N A
A
VrdNt
0
NA
t21
![Page 22: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/22.jpg)
CSTR Mole Balance
FA 0 FA rA dV dNA
dt
dNA
dt0Steady State
CSTR
22
![Page 23: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/23.jpg)
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
23
![Page 24: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/24.jpg)
Plug Flow Reactor
24
![Page 25: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/25.jpg)
Plug Flow Reactor Mole Balance
V
V VV
FA
FA
0
0
VrFF
VinGeneration
VVatOut
VatIn
AVVAVA25
![Page 26: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/26.jpg)
limV 0
FA V V FA V
VrA
Rearrange and take limit as ΔV0
dFA
dVrA
Plug Flow Reactor Mole Balance
26
This is the volume necessary to reduce the entering molar flow rate (mol/s) from FA0 to the exit molar flow rate of FA.
![Page 27: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/27.jpg)
Alternative Derivation – Plug Flow Reactor Mole Balance
0 0 dVrFF AAA
0dt
dN ASteady State
dtdNdVrFF A
AAA 0
PFR
27
![Page 28: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/28.jpg)
dFA
dVrA
0 dFA
dV rA
Differientiate with respect to V
A
A
F
F A
A
rdFV
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
28
![Page 29: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/29.jpg)
dt
dNWrWWFWF AAAA
AWAWWA
Wr
WFF
0lim
0dt
dN ASteady State
PBR
Packed Bed Reactor Mole Balance
29
![Page 30: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/30.jpg)
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
rdFW
0
The integral form to find the catalyst weight is:
30
![Page 31: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/31.jpg)
Reactor Mole Balance SummaryReactor
Differential Algebraic Integral
V FA 0 FA
rA
CSTR
Vrdt
dNA
A 0
A
A
N
N A
A
VrdNtBatch
NA
t
dFA
dVrA
A
A
F
F A
A
drdFV
0
PFRFA
V31
![Page 32: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/32.jpg)
Reactors with Heat EffectsEXAMPLE: Production of Propylene Glycol in
an Adiabatic CSTR
Propylene glycol is produced by the hydrolysis of propylene oxide:
CH2 CH CH3 H2OH2SO4 CH2 CH CH3
O
OH
OH
Fast Forward 10 weeks from now:
32
![Page 33: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/33.jpg)
What are the exit conversion X and exit temperature T?SolutionLet the reaction be represented by
A+BC
v0
Propylene Glycol
33
![Page 34: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/34.jpg)
34
![Page 35: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/35.jpg)
35
![Page 36: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/36.jpg)
36
![Page 37: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/37.jpg)
37
![Page 38: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/38.jpg)
38
![Page 39: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/39.jpg)
39
Evaluate energy balance terms
![Page 40: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/40.jpg)
40
![Page 41: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/41.jpg)
41
![Page 42: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/42.jpg)
AnalysisWe have applied our CRE algorithm to calculate the Conversion (X=0.84) and Temperature (T=614 °R) in a 300 gallon CSTR operated adiabatically.
X=0.84T=614 °R
T=535 °R
A+BC
42
![Page 43: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/43.jpg)
KEEPING UP
43
![Page 44: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/44.jpg)
Separations
These topics do not build upon one another
Filtration Distillation Adsorption
44
![Page 45: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/45.jpg)
Reaction Engineering
Mole Balance Rate Laws Stoichiometry
These topics build upon one another
45
![Page 46: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/46.jpg)
Mole BalanceRate Laws
StoichiometryIsothermal Design
Heat Effects
46
![Page 47: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/47.jpg)
Mole Balance Rate Laws
47
![Page 48: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/48.jpg)
Mole Balance
Rate LawsStoichiometry
Isothermal DesignHeat Effects
48
![Page 49: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/49.jpg)
End of Lecture 1
49
![Page 50: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/50.jpg)
Additional Applications of CRE
50
Supplemental Slides
![Page 51: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/51.jpg)
Additional Applications of CRE
51
![Page 52: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/52.jpg)
52
![Page 53: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/53.jpg)
53
![Page 54: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/54.jpg)
Compartments for perfusion
Perfusion interactions between compartments are shown by arrows.
VG, VL, VC, and VM are -tissue water volumes for the gastrointestinal, liver, central and muscle compartments, respectively.
VS is the stomach contents volume.
StomachVG = 2.4 l
GastrointestinalVG = 2.4 ltG = 2.67 min
Liver
Alcohol
VL = 2.4 l tL = 2.4 min
CentralVC = 15.3 l tC = 0.9 min
Muscle & FatVM = 22.0 l tM = 27 min
54
![Page 55: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/55.jpg)
55
![Page 56: Lecture 1](https://reader036.vdocuments.mx/reader036/viewer/2022062520/5681625c550346895dd2b147/html5/thumbnails/56.jpg)
56