Mass Transfer
467
Table 10,11, Parameters for the pellet system considered.
Parameter
Value
k
0.50 kg m'J (pellet) h
'1
a
0.2
Ssurface
0 .10
kgnf
5
Ds
6
10
'
10
m
2
s
'1
KP
2
10 '3
m
0.5
We do not have an analytical expression for the effectiveness factor for a sphere with a reaction obeying
Monod kinetics. However, Eq.(10.44) may be solved numerically, using a suitable numerical method.
With a centered finite difference method, using 200 grid points, the concentration profile given in Fig. 10.11
is obtained.
Fig. 10.11. The substrate concentration as a function of radial position in the pellet.
Fig. 10.12. The substrate consumption rate (-qs) plotted versus the radial position in the pellet.
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