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In many commercial applications, separation processes
are essential and can account for as much as 40%–70% of
chemical plant capital and operating costs.
1
A new look
at gas separations is particularly important now because
of contemporary issues such as alternative energy and
environmental “green” efforts. If new applications such
as coal gasication and oxyfuel combustion that use
oxygen instead of air
2–3
are economical, they will sig-
nicantly increase the demand for oxygen worldwide.
4
The state of the art in air separation is comprised of three
alternatives: cryogenic distillation, adsorption-based pro-
cesses, and membrane technologies. ...