
48 Oxygen-Enhanced Combustion
with the continual development of environmentally
friendly refrigerants.
If only oxygen and a small amount of nitrogen are
required as products, a signicant portion of the air is
available as a nitrogen-rich waste gas. Chilled water
can be generated in a humidication tower by passing
that waste gas countercurrently against cooling water.
It is possible to chill water to a colder temperature than
the waste gas since the waste is dry, its wet bulb tem-
perature will be several degrees colder. The chilled
water can then be used to cool the air stream in a shell
and tube heat exchanger or preferably by directly con