Page 101 - Packed bed columns for absorption, desorption, rectification and direct heat transfer

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The installations must ensure stable inlet concentrations of the gas and
liquid phase.

2.1.1.1. Classical installation
A classical installation for absorption and desorption experiments with
packings is Prof. Billet's installation described in his latest book [86]. The
installation presented in Fig. 1 includes an absorber with a distributor and the
investigated packings, two vessels for preparing of absorbent, respectively
saturated liquid for desorption, a gas analyzer, manometers, a blower, a
humidifier, a gas bottle, a column for mixing of the absorbed gas from the bottle
with air, and the necessary rotameters for measuring the flow rates of gas and
liquid.
The only disadvantage of the installation presented in Fig. 1 is very big
volumes of the vessels. For example in ease of a 500 mm column diameter, at
2
2
liquid superficial velocity 200 m /(m h), the volume of each vessel insuring 1
hour operation of the column is

,200 = 39.54
4

The providing of a constant concentration in the whole volume of such
a vessel needs significant time (the necessary pump or agitators are not given in
Fig. 1). The volumes of the vessels can be reduced up to four times by preparing
absorbent only for one experiment. The increasing of the level height of the
liquid during the experiment requires using automatic regulation of the liquid
flow rate.
The mixing of the gases can be provided better in a long pipe which has
quite smaller residence time.
To escape the mentioned disadvantages, in his experiments the author
of the present book uses the installation presented in Fig. 2 built at his
laboratory at the Institute of Chemical Engineering of the Bulgarian Academy
of Sciences.