Computation of the Volume of a CSTR and a PFR
Computation of the Volume of a CSTR and a PFR
A harmful industrial organic compound, A, found in waste water, is transformed using an enzyme into a harmless product. Laboratory tests using a specific quantity of the enzyme in a mixed flow reactor give the following data:
C A o | mmol/ 3 m | 2 | 5 | 6 | 6 | 11 | 14 | 16 | 24 |
C A | mmol/ 3 m | 0.5 | 3 | 1 | 2 | 6 | 10 | 8 | 4 |
τ | min | 30 | 1 | 50 | 8 | 4 | 20 | 20 | 4 |
Here is the residence time in minutes and and are the inlet and outlet concentration of A in mmol/.
τ
C
A
0
C
A
3
m
This Demonstration computes the reactor volume (expressed in ) needed to treat of this waste water for =10mmol/ in order to achieve a user-specified value of the conversion . Two types of reactor are considered: PFR (plug flow reactor) and CSTR (continuous stirred-tank reactor). The reactor residence time, in minutes, is equal to the shaded area shown in the figure.
V
3
m
F=0.1/min
3
m
C
A
0
3
m
X=1-
C
A
C
A0
τ
For a PFR:
τ==d
V
F
C
A
∫
C
A
0
-1
r
A
C
A
For a CSTR:
τ==X
V
F
C
A
0
-
r
A