PROCESS FOR RECOVERING H2 FROM A GAS MIXTURE

摘要

1534667 Separating hydrogen from gas mixtures BERGWERKSVERBAND GmbH 28 July 1977 [28 July 1976 3 Nov 1976] 31817/77 Heading B1L H 2 is separated from a gas mixture containing H 2 , CH 4 , at least 5 volume % of N 2 and/or CO and, optionally, higher hydrocarbons, CO 2 and trace impurities, e.g. O 2 , NO x , H 2 S, COS, mercaptans, NH 3 or H 2 O, by uniform cycles of adsorption of desorption of the mixture in an adsorber filled with a carbonaceous adsorbent, wherein (a) the mixture is passed to the adsorber, optionally under elevated pressure, for adsorption of CH 4 , CO, and any trace impurities and higher hydrocarbons in a first zone towards the adsorber inlet and adsorption of N 2 and/or CO in a second zone towards the adsorber outlet, the H 2 being unadsorbed and leaving the adsorber; and (b) when the second zone has diminished to a length of not less than 30% of the overall adsorber length but before the first breakthrough of N 2 and/or CO at the outlet, desorbing the adsorbed gases by closing the outlet and releasing any pressure and evacuating the adsorber from its inlet. The N 2 and/or CO which are desorbed on pressure reduction and any remaining hydrogen pass in reverse flow from the second zone to the inlet and act as scavenging gas to desorb the gases adsorbed in the first zone. The adsorber may then be prepared for re-use by re-pressurisation to atmospheric pressure with hydrogen.