ABSTRACT
Early air separation plants were designed primarily for the economic production of low-cost
gaseous products to be supplied in high-pressure cylinders (150 bar) for industrial applica-
tions. The production of either liquid oxygen or liquid nitrogen was of a secondary consid-
eration. Liquids were produced, however, but in small quantities, and essentially for use in
research work at low temperatures in university laboratories. Small plants for total liquid
production were also designed for the supply of liquid oxygen to coal mines in eastern France
and in certain locations in the United States for the manufacture of liquid oxygen explosives.
This application involved the use of activated carbon saturated with liquid oxygen enclosed in
cartridges of nonflammable material. It has now been completely eliminated because of the
relative high cost of cryogenic liquids versus the lower cost of standard chemical explosives.
