LOW TEMPERATURE PRESSURE SWING ABSORPTION BY COOLING

摘要

PURPOSE: To carry out enhanced gas separation without the need for an external cooling source under optimum temperature conditions by disposing an internally generated self cooling retention means controlled to lower the average temperature of an absorption medium bed. CONSTITUTION: An absorption vessel 1 having the self-coolable PSA bed has a drying section 5 between heat regeneration zones 4 and 6. The absorption medium bed 7 exists on the drying section 5 and is constituted as a main region for selective nitrogen absorption from air. The temperature shift of the absorption medium bed 7 of a zeolite sieve existing in an equilibrium state with the air is, about -5 deg.C when the bed pressure changes from 150 kpas to 50 kpa and is about -6 deg.C in the case of the pure nitrogen and about -2 deg.C in the case of the pure oxygen. This temperature fall occurs near the supply end of the absorption bed 7 which is the nitrogen absorption zone and further, the smaller temperature fall occurs downstream of the absorption bed 7. The internal cooling of the substantial quantity is spontaneously generated in the process of the PSA process cycle in which such pressure change occurs.