
94 Oxygen-Enhanced Combustion
regeneration with low-pressure, dry air, (v) countercur-
rent pressurization to moderate pressure (with gas from
parallel bed), and (vi) co-current repressurization to
high pressure with feed.
The key feature of CZPSA is its use of low-pressure air
for the purge step. This results in a higher recovery of
pressurized O
2
but with a lower O
2
purity as a result of
incomplete clean-out during the purge step. For relatively
low oxygen product purities, CZPSA recovers more high-
pressure oxygen product than conventional PSA.
51,52
For
example, under base operating conditions with a high
pressure of 5bar and a low pressure ...