Using either the data in Table E2-W.1, calculate the reactor volumes V1, V2, and V3 for the CSTR/PFR/CSTR reactors in series sequence shown in Figure E2-W.1 along with the corresponding conversion.
Figure E2-W.1 CSTR/PFR reactor in series.
|
X |
0 |
0.2 |
0.4 |
0.6 |
0.8 |
|
|
0.010 |
0.0091 |
0.008 |
0.005 |
0.002 |
|
|
100 |
110 |
125 |
200 |
500 |
|
|
200 |
220 |
250 |
400 |
1000 |
Solution
We again use the plot of 
Figure E2-W.2 Levenspiel plot for CSTR/PFR/CSTR sequence.
(a) The CSTR design equation for Reactor 1 is
(E2-W.1)
at X = X1 = 0.4 the (FA0/-rA1) = 300 dm3
V1 = (300 dm3) (0.4) = 120 dm3
The volume of the first CSTR is 120 dm3.
(b)Reactor 2: PFR The differential form of the PFR design is
(E2-W.2)
Rearranging and integrating with limits
when V = 0 X = X1 = 0.4
when V = V2 X = X2 = 0.7
(E2-W.3)
Choose three point quadrature formula with 
(E2-W.4)
Interpreting for (FA0/-rA) at X = 0.55 we obtain
The volume of the PFR
is 
(c) Reactor 3: CSTR
Balance
(E2-W.5)
Rearranging
(E2-W.6)
(E2-W.7)
(E2-W.8)
(E2-W.9)
The volume of the last CSTR is 180 dm3.
