Nitrogen and oxygen prodn. by air sepn. - by treating cooled compressed air in vortex tube

摘要

The process involves subjecting air to (i) compression to 0.3-0.6 MPa,(ii)coolingtothesatd.stateat90-100K,and(iii)sepn. in one or more vortex tubes. Step (iii) may be carried out under adiabatic conditions with cooling of the air to a 20-40 wt.% liq. content. For improved prod. purity adiabatic sepn. may be replaced by or supplemented by sepn. in a vortex tube in thermal contact with the ambient medium with cooling of the air to a 45-65 wt.% liq. content. The process is used for prodn. of nitrogen and oxygen or oxygen-enriched air, e.g. for refrigerated vehicles. It uses cmpact equipment, which can function in the inclined condition, and requires only small amts. of liq. air so that the process can be stopped and started rapidly. Heat entry into the low temp. region of the equipment is low and energy consumption is less than that of single rectification columns.