PROCESS FOR SEPARATING GAS MIXTURES SUCH AS HYDROGEN CONTAINING CARBON DIOXIDE AND NITROGEN IMPURITIES, BY ADIABATIC PRESSURE SWING ADSORPTION

摘要

1505957 Adiabatic pressure swing process UNION CARBIDE CORP 30 June 1976 [7 Nov 1975] 27160/76 Heading B1L An adiabatic pressure swing process, e.g. for separating hydrogen from carbon oxides and nitrogen impurities, using at least seven adsorbent beds, having at least three pressure equalization stages and in which at least two beds receive feed gas mixture during the entire cycle comprises simultaneously introducing feed gas mixture to the inlet ends of at least two adsorbent beds in overlapping identical cycles sequentially from the first to the highest numbered bed and thereafter continuously repeating the sequence such that during the initial period of a bed adsorption step the immediately preceding lower numbered bed is also on its adsorption step and during the last period the immediately following higher numbered bed is also on its adsorption step, and performing the initial void space gas releasing-pressure equalization in at least three separate phases comprising first pressure equalizing the adsorbent bed having completed its one component adsorption step, with a different previously purged and at least third higher numbered bed initially at lower intermediate pressure so that the two beds are finally at a first equalization pressure, second pressure equalizing the one componentcontaining adsorbent bed initially at said first equalization pressure with a still different previously purged and at least fourth higher numbered bed initially at still lower intermediate pressure so that the two beds are finally at a second equalization pressure, and third pressure equalizing the one componentcontaining adsorbent bed initially at said second equalization pressure with another previously purged and at least fifth higher numbered bed initially at lowest pressure so that the two beds are finally at a third equalization pressure, and third pressure equalizing the one component-containing adsorbent bed initially at said second equalization pressure with another previously purged and at least fifth higher numbered bed initially at lowest pressure so that the two beds are finally at a third equalization pressure. The absolute pressure ratio, PR, of the first highest superatmospheric pressure of the adsorption step to the lowest pressure of the process is preferably at least 7, and the product PRX molar ratio of the non adsorbates in the bed at the end of the adsorption step to the total feed gas introduced during adsorption step is at least 6. Examples are given using 7, 8, 9 and 10 beds.