Page 221 - Adsorption Technology & Design, Elsevier (1998)

Selected adsorption processes 203

r

Leading
Trim Regeneration
bed bed
bed

A ~ B---~ *'"-"--C

J

Dryer

I_
.... i
!

Figure 7. 7 Improvement of bed capacity using three beds.

Figure 7.7. Feed first enters bed A (called the lead bed), in which adsorption
occurs, and subsequently passes through bed B which has had the least time
on stream since regeneration. The adsorbate is allowed to break through
bed A prior to passage through bed B (termed the trim bed) without
allowing breakthrough from bed B. By this means bed A can be fully utilized
before it is taken off stream for regeneration. Bed B then becomes the lead
bed and the third bed, bed C, becomes the trim bed. Initially, therefore, bed
A is the leading adsorber, bed B the trim adsorber while bed C is being
regenerated. Each bed then reverts to an alternative role.

7.5 COMMERCIAL TSA PROCESSES

Commercial applications of thermal swing processes are more commonly for
the purification of gases and liquids than for the bulk separation of gases.