Transcript CHAPTER 3 MASS BLANCE, FLOW MODELS, AND

CHAPTER 3 MASS BLANCE, FLOW
MODELS, AND REACTORS
FLOW MODELS
1.
2.
3.
4.
Batch
Plug Flow (PF)
Continuously Stirred Tank Reactor (CSTR)
or Completely Mixed Flow (CMF)
Dispersed Plug Flow (DPF)
Batch Reactor
CA0
1ST order reation
t0
dC A
  KC A
dt
CA1
t1
t
dCA
CA0 C A   K 0 dt
C A1
C A1
 exp( Kt )
C A0
Plug Flow (PF) 1/2
Q
d Vr
CA- d CA
CA
Q
CA1
QCA  Q(CA  dCA )  rAdVr
QdCA  rAdVr
QdCA  kCAdVr
Plug Flow (PF) 2/2

C A1
C A0
dCA
k

CA
Q
Vr

0
dVr
C A1
Vr
n(
)  k
 k
C A0
Q
C A1
 exp(k )
C A0
Plug Flow和
Batch
公式相同
Continuously Stirred Tank Reactor
(CSTR) 1/2
Accumulstion  Input Output Re action
dCA1V  CA0Qdt  CA1Qdt  VkCA1
CA0
t0
dC A
Q
 C A0  C A1Qdt  kC A1
dt
V
CA1
t1
Steady state dC/dt=0 , 1/θ= θ/V
Continuously Stirred Tank Reactor
(CSTR) 2/2
0
C A0


C A1

 kC A1
C A1
1

C A0 1  k
C A1
1
(
)C A 0
1  k
C A0  C A1

kCA1
C A0  C A1
k 
C A1
Continuously Stirred Tank Reactor
(CSTR)串聯 1/2
CA0
Q
CA1 Q
V1
CA2 Q
CAn-1
V2
CAn Q
Vn
Continuously Stirred Tank Reactor
(CSTR)串聯 2/2
C A1
1

C A0 1  k
C A2
，
C A2
1

C A1 1  k
C A2  (
1
)C A1
1  k
1
1
(
)(
)C A0
1  k 1  k
C A2
1
(
)2
C A1
1  k
C An
1 n
(
)
C A1
1  k
Completely Mixed Flow (CMF)
Ｑ
Ｑ
C1
C０＝C1
Accumulstion  Input Output Re action
VdC1  0  0  C1Qdt

C1
C0
dC1
Q t
   dt
C1
V 0
C1
Q
t
 exp( t )  exp( )
C0
V
t
Dispersed Plug Flow (DPF) 1/2
d Vr
Q
Q
CA
CA1
Dispersion number
Axial velocity
L2
T
D
d
VL
Dispersed Plug Flow (DPF) 2/2