ABSTRACT
Georges Claude successfully employed an expansion machine in air separation for the
first time in 19021. The principle employed was well known at the time and was based
on performing work during the expansion of a gas. With the extraction of energy from
the gas, there is a drop in enthalpy of the expanded gas with little or no increase in entropy.
Refer to Figure 2.6. The actual drop in temperature of the gas is a function of the gas
component or mixture being expanded, the pressure ratio of expansion, the temperature
and pressure at the inlet of the expander, and the mechanical efficiency of the expansion of
the system.
