Page 272 - Elements of Chemical Reaction Engineering 3rd Edition

244 Collection and Analysis of Rate Data Chap. 5

Inert
filling

Most commonly
used catalytic
reactor to obtain FAO
experimental data

Figure 5-8 Differential reactor
The differential reactor is relatively easy to construct at a low cost.
Owing to the low conversion achieved in this reactor; the heat release per unit
volume will be_sr_mall (or can be made small by diluting the bed with inert sol-
ids) so that the reactor operates essentially in an isothermal manner. When
operating this reactor, precautions must be taken so that the reactant gas or liq-
uid does not bypass or channel through the packed catalyst, but instead flows
Limitations of the uniformly across the catalyst. If the catalyst under investigation decays rapidly,
differential the differential reactor is not a good choice because the reaction rate parame-
ters at the start of a run will be different from those at the end of the run. In
some cases sampling and analysis of the product stream may be difficult for
small conversions in multicomponent systems.
The volumetric flow rate through the catalyst bed is monitored, as are the
entering and exiting concentrations (Figure 5-9). Therefore, if the weight of

- t
FAO
CAO

+------AW-l
Figure 5-9 Differential catalyst bed