Propylene Recovery from Propylene/Propane/Nitrogen Mixture by PSA Process

Abstract

This study is on the process performance (purity, recovery and productivity) of a four-bed bench-scale PSA unit [1000 mm (L) × 25 mm (ID) × 4 beds], with which is applied to enrich propylene from propylene/propane/nitrogen gas mixture (35 mol% propylene, 15 mol% propane, 50 mol% nitrogen). Adsorbent, i.e. AgNO3 impregnated on silica substrate, was prepared and loaded in the above PSA unit. The unit was operated at the pressure of 25–870 mmHg and at the temperature of 10–70∘C. By a four-bed PSA process at 50∘C, the propylene product purity and recovery were 91.9 mol% (7.0 mol% propane, 1.1 mol% nitrogen) and 86.5%, respectively. More than 99% of nitrogen was removed from the feed. The propylene productivity by the process was 0.89 mol/(kg ⋅ hr).