Post on 19-Dec-2015
transcript
Lecture 12 Tuesday 2/12/08
Multiple Reactions
Selectivety and Yield
Series Reactions
Complex Reactions
Department of Chemical Engineering, University of Michigan, Ann Arbor
2 HSF, 04/18/23
Many metabolic reactions involve a large number of sequential reactions, such as those that occur in the coagulation of blood.
Cut → Blood → Clotting
Blood Coagulation
Figure A. Normal Clot Coagulation of blood
(picture courtesy of: Mebs, Venomous and Poisonous Animals, Medpharm, Stugart 2002, Page 305)
Department of Chemical Engineering, University of Michigan, Ann Arbor
3 HSF, 04/18/23
Schematic of Blood Coagulation
Department of Chemical Engineering, University of Michigan, Ann Arbor
4 HSF, 04/18/23
Cut
A + B
C
D
E
F
Clot
Department of Chemical Engineering, University of Michigan, Ann Arbor
5 HSF, 04/18/23
MODEL EQUATIONS:
Department of Chemical Engineering, University of Michigan, Ann Arbor
6 HSF, 04/18/23
MODEL EQUATIONS:
Multiple Reactions
example: A → B → C
(1) A → B
(2) B → C
1) Mole balances:
2) Rates: rate laws:
relative rates:
3) Combine:
CC
BB
AA r
dt
dCr
dt
dCr
dt
dC
BB
AA
Ckr
Ckr
22
11
11
11
2211 CBBA rrrr
BAAC
tktkAB
Btk
ABB
BABBB
tkAAAA
A
CCCC
eekk
CkC
C teCkCkdt
dC
CkCkrrdt
dC
eCCCkrdt
dC
0
12
01
012
2121
01
21
1
1
0 ,0at
When is CB the highest?
12
1
2
1
2
2112
01
ln
0
12
21
kk
kk
tk
ke
ekekkk
Ck
dt
dC
tkk
tktkAB
Example: CSTR multiple reactions A → B → C
what is the optimal ?
1) Mole Balance:
0
00
0
0
0
0
0
000
0
BB
BB
AAA
AAA
AAA
rC
VrCV
rCC
VrVCVC
VrFF
2) Rates: laws: net:
relative:
3) Combine:
BB
AA
Ckr
Ckr
22
11
BABBB
AAA
CkCkrrr
Ckrr
2121
11 0
11
112211 CBBA rrrr
21
max
12
01
2
1
21
1
0
10
1
11
1
0
1
0
kk
kk
CkC
k
CkC
CkCkC
k
CC
CkCC
AB
AB
BAB
AA
AAA
0d
dCB
Example: Liquid phase PFR
A + 2B → C (1)
2A + 3C → D (2)
1) Mole balances:
2) Rates: laws:
net:
relative:
3) Stoich:
overall selectivity:
parameters:
DD
CC
BB
AA r
dV
dFr
dV
dFr
dV
dFr
dV
dF
3222
211 CACCBAAA CCkrCCkr
DDCCC
BBAAA
rrrrr
rrrrr
221
121
CDCADCA
ABACCBA
rrrrrrr
rrrrrrr
2222222
1111111
3
1
3
2
132
2 121
15 ,10
2 ,2 ,250 ,100
21
000
AA
BA
kk
CCVV
00000
V VV
FC
V
FC
V
FC
V
FC D
DC
CB
BA
A
0
0 0000001.0
~
A
AA
D
C
D
C
F
FFX
F
F
F
FS