초록 ▼

Pressure swing adsorption operations for the selective adsorption of a component of a gas mixture is carried out, in multi-bed systems, so that the gas released from a bed during the cocurrent depressurization, provide-purge step is passed partly to another bed and partly to an external vessel. The

Pressure swing adsorption operations for the selective adsorption of a component of a gas mixture is carried out, in multi-bed systems, so that the gas released from a bed during the cocurrent depressurization, provide-purge step is passed partly to another bed and partly to an external vessel. The gas in said vessel is thereafter used to partially repressurize said other bed after it has completed its purge step.

대표청구항 ▼

In a pressure swing adsorption process for the selective adsorption of at least one component of a feed gas mixture in an adsorption system having at least four adsorbent beds, each of which undergoes, on a cyclic basis, (1) higher pressure adsorption, (2) cocurrent depressurization from said higher

In a pressure swing adsorption process for the selective adsorption of at least one component of a feed gas mixture in an adsorption system having at least four adsorbent beds, each of which undergoes, on a cyclic basis, (1) higher pressure adsorption, (2) cocurrent depressurization from said higher pressure to upper intermediate pressure(s) with release of void space gas from the product end of the bed, said gas being passed directly to another bed(s) in the system and initially at a lower pressure than said upper intermediate pressure(s) for pressure equalization therebetween (3) further cocurrent depressurization from said upper intermediate pressure reached at the completion of step (2) above to a lower intermediate pressure with release of additional void space gas from the product end of the bed, said gas being passed directly to another bed in the system at its lower desorption pressure to provide purge gas directly to said other bed to be purged, (4) purge, in which void space gas released from another bed is passed directly thereto, with or without prior countercurrent depressurization to a lower desorption pressure, (5)partial repressurization to said upper intermediate pressure(s) by the addition of void space gas thereto, said gas being passed to the bed from another bed(s) in the system and initially at a higher pressure than said upper intermediate pressure(s) for pressure equalization therebetween and (6) final repressurization to said higher adsorption pressure from the upper intermediate pressure reached upon completion of said pressure equalization, the improvement consisting essentially of: (a) passing a portion of the void space gas released from the product end of the adsorbent bed during step (3) above to an empty external vessel for the repressurization thereof simultaneously with the passage of another portion of said void space gas directly to another adsorbent bed in the system to be purged during step (3) above: and (b) passing void space gas from the thus-repressurized external vessel to the same adsorbent bed into which void space gas was passed directly during step (3) above, with said passage of gas from the external vessel to said bed occurring immediately after said bed completes said purge step using purge gas provided directly in step (3) above, thus partially repressurizing said purged bed, to a pressure greater than its lower desorption pressure prior to further partial repressurization in step (5) above to upper intermediate pressures by pressure equalization with another bed or beds in the adsorption and subsequent final repressurization to said higher adsorption pressure in step (6) above, whereby the product recovery and/or purity obtained in the system are enhanced.