Performance of a 5A molecular sieve in separating a gaseous mixture of nitrogen and oxygen

Abstract

This paper describes the results of an experimental study involving the performance of a relatively new type of 5A molecular sieve (5AMG) in separating a mixture of gaseous oxygen and nitrogen due to the selective adsorption of nitrogen. Pure nitrogen, was passed through a 5AMG molecular sieve bed, maintained at ambient temperatures, and preloaded with pure oxygen at 7.80 atm. Following this procedure, the molecular sieve bed was reconditioned and reloaded with pure oxygen at 7.80 atm. Then, a synthetic air mixture (21% oxygen, 79% nitrogen) was passed through the adsorption bed. The nitrogen displaced the preloaded oxygen in a fixed period of time ( T 0), depending on a controlled and predetermined oxygen elution rate, from the exit end of the adsorption bed. The synthetic air mixture also displaced the preloaded oxygen. However, the selective adsorption of nitrogen, from the synthetic air stream, resulted in the production of an additional quantity of relatively pure oxygen. Therefore, in the case of the synthetic air purging, relatively pure oxygen was produced in the eluted gas stream for an extended period of time ( T). The difference in these time periods ( T− T 0), at fixed flow rates, permitted a determination of the effectiveness of the 5AMG molecular sieve in separating the nitrogen and oxygen mixture.