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300 4. Adsorption and Ion Exchange

0.70

0.60

0.50

U(t)
0.40

U(t) , experimental
0.30
U(t) , model

0.20
0 2000 4000 6000 8000 10000 12000
t (sec)
Figure 4.19 The performance of the model.

By a trial-and-error procedure, using the v alue of U ( t ) and the model eqs. (4.52)–(4.58),
the solid-phase diffusion coeficient is found to be 1.3 10 –12 m 2 /s. This value is v ery
f
close to the one gien in the study of Meshk v o et al . The trial-and-error procedure can be
alue of done easily. By changing the v D , the model predicts the v alues of U ( t ) for each t .
s
The best value of D s is the one that results in the lowest mean deviation between the exper-
imental and the model values of U ( t ). In Figure 4.19, the performance of the model is
shown. The average error is 3.1%.

Reactor design Using the typical dimension ratios of an agitated vessel (see Section 3.3.5):

4   13
D T   V   5.03 cm

D T
D a 1.68 cm
3

D
B T 5 mm
10
ic system Four baffles and a propeller with three blades could be used. Thus, for this specif
(eq. (3.104)),

DN a 2
N 1000
Re