| 摘要 |
<p>PURPOSE:To surely recover cold and to efficiently recover nitrogen by countercurrently introducing a nitrogen-enriched effluent gas from a parallel-flow purging stage free of moisture and having cold, and increasing the pressure to atmospheric pressure. CONSTITUTION:An adsorption tower 1a is switched to a countercurrent pressure increasing stage, a valve 6a is opened, a dry low-temp. gas leaving an adsorption tower 1c in the purging stage kept at -15 deg.C, having <=-50 deg.C dew point and contg. 80vol.% nitrogen is countercurrently introduced into the adsorption tower 1a to increase the pressure in the tower. Meanwhile, air is introduced into an adsorption tower 1b to increase the pressure in the tower, dehumidified to <=-50 deg.C dew point by a dehumidifying agent bed 2, cooled to -10 deg.C by a cold storage material bed 3 and cooled to -15 deg.C by a coldest heat exchanger 4, nitrogen is adsorbed by an adsorbent bed 5, and oxygen is discharged outside the system. The intrusion of moisture into a nitrogen adsorbent is prevented in this way, the deterioration with lapse of time is obviated, cold is surely recovered, and nitrogen is efficiently recovered.</p> |
