Lecture 12
description
Transcript of Lecture 12
![Page 1: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/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 12
![Page 2: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/2.jpg)
Lecture 12 – Tuesday 2/15/2011Multiple Reactions
Selectivity and Yield
Series Reactions
Complex Reactions
2
A DkD
A UkU
A B C
A + B C + D
A + C E
![Page 3: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/3.jpg)
4 Types of Multiple ReactionsSeries: A → B → CParallel: A → D,
A → UIndependent: A → B,
C → DComplex: A + B →C + D,
A + C → EWith multiple reactors, either molar flow or number of moles must be used (no conversion!)
3
![Page 4: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/4.jpg)
Instantaneous
Overall
There are two types of selectivity and yield: Instantaneous and Overall.
Selectivity and Yield
U
DDU r
rS U
DDU F
FS ~Selectivity
A
DD r
rY
AA
DD FF
FY
0
~Yield
4
![Page 5: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/5.jpg)
ABA
BA
U
DUD C
kk
CCkCCk
rrS
2
1
2
21
To maximize the selectivity of D with respect to U run at high concentration of A and use PFR.
DBA 1k BAD CCkr 21Example: Desired Product:
UBA 2kBAU CCkr 2Undesired Product:
5
Selectivity and Yield
![Page 6: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/6.jpg)
Gas Phase Multiple Reactions
6
![Page 7: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/7.jpg)
Flow Batch
BB
AA
rdVdF
rdVdF
VrdtdN
VrdtdN
BB
AA
Multiple Reactions Chapter 8
7
A) Mole Balance of each and every Species
![Page 8: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/8.jpg)
8
A) Rates:a) Rate law for each reaction
AAi
iAA rrrr 211
b) Net Rates
c) Relative Rates
ACAA
BAAA
CCkrCCkr
22
11
Multiple Reactions Chapter 8
![Page 9: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/9.jpg)
TT
PP
FFCCA
ATA
0
000
Stoichiometry:
Gas
Example: A → B → C (1) A → B k1
(2) B → C k29
0AA FC
Multiple Reactions Chapter 8
Liquid
![Page 10: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/10.jpg)
AC
AB
AA r
dtdC r
dtdC r
dtdC
V=V0 (constant batch)
10
1) Mole Balance:
Vrdt
dN
Vrdt
dN
Vrdt
dN
CC
BB
AA
Example: Batch Series Reactions
![Page 11: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/11.jpg)
B2B1B
A1A
BB1B1
AA1A1
rrrrr
CkrCkr
Laws
Net rates
2) Rates:
111
r1
r1r
1r
C2B2
B1A1
Relative rates
Example: Batch Series Reactions
![Page 12: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/12.jpg)
example: A → B → C(1) A →
B (2) B →
C
1) Mole Balance:
CC
BB
AA r
dtdC r
dtdC r
dtdC
ttop
t
Ci
A BC
12
sVV
Example: Batch Series Reactions
![Page 13: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/13.jpg)
1r
1r
1r
1r C2B2B1A1
Relative:
B2B2
A1A1
CkrCkr
Laws:
13
2) Rates:
Example: Batch Series Reactions
![Page 14: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/14.jpg)
BB r
dtdC
Species B:
B2A1B2B1NET BB CkCkrrrr
tkexpCkCkdt
dC10A1B2
B 14
Species A: A1AA Ckr
dtdC
tkexpCC 10AA
3) Combine:
Example: Batch Series Reactions
![Page 15: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/15.jpg)
Using the integrating factor, tkexpdtkexp.F.I 22 tkkexpCk
dttkexpCd 120A1
2B
at t = 0, CB=0
BA0AC CCCC
15
tk1
tk2
12
0AC
21 e1ke1kkk
CC
Example: Batch Series Reactions
![Page 16: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/16.jpg)
what is the optimal ?
00 AAA rCC
000 0
BB
BB
rCVrCv
00
000
0
VrvCvC
VrFF
AAA
AAA1) Mole Balance:
Example: CSTR Series ReactionsABC
16
![Page 17: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/17.jpg)
2) Rates:
B2B2
A1A1
CkrCkr
Laws:
B2A1B2B1B
A1A1A
CkCkrrrCk0rr
Net:
1r
1r
1r
1r C2B2B1A1
Relative:
17
Example: CSTR Series ReactionsABC
![Page 18: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/18.jpg)
3) Combine:
18
Example: CSTR Series ReactionsABC
![Page 19: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/19.jpg)
dCBd
0
max 1k1k2
19
Find that gives maximum concentration of B
12
01
11 kkCkC A
B
Example: CSTR Series ReactionsABC
![Page 20: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/20.jpg)
20
![Page 21: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/21.jpg)
End of Lecture 12
21
![Page 22: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/22.jpg)
Supplementary Slides
22
![Page 23: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/23.jpg)
Supplementary Material - Blood Coagulation
23
![Page 24: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/24.jpg)
24
![Page 25: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/25.jpg)
Notations
25
![Page 26: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/26.jpg)
Notations
26
![Page 27: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/27.jpg)
Mole Balance
27
![Page 28: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/28.jpg)
Mole Balance
28
![Page 29: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/29.jpg)
Mole Balance
29
![Page 30: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/30.jpg)
Result
30
![Page 31: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/31.jpg)
Blood CoagulationMany metabolic reactions involve a large number of sequential reactions, such as those that occur in the coagulation of blood.
Cut → Blood → Clotting
Figure A. Normal Clot Coagulation of blood(picture courtesy of: Mebs, Venomous and Poisonous Animals, Medpharm, Stugart
2002, Page 305)31
![Page 32: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/32.jpg)
Schematic of Blood Coagulation
32
![Page 33: Lecture 12](https://reader036.fdocuments.us/reader036/viewer/2022062501/56815cda550346895dcae39a/html5/thumbnails/33.jpg)
Cut
A + B
C
D
E
F
Clot33