ABSTRACT
The separation of air involves more than thermodynamic calculations. It also involves the use
of equipment such as heat exchangers, valves, compressors, expanders, pumps, etc. The
individual operability of these items in terms of process efficiency and operating reliability
is of fundamental importance in the choice of any cryogenic process cycle. Moreover, much
of this equipment must operate in a reliable and efficient manner at temperatures well below
173 K (1008C).