Purification of gas mixtures

摘要

The invention concerns a process for the purification of a hydrogen-containing gas mixture comprising up to 45% by volume of hydrogen, together with carbon oxides, hydrogen cyanide and impurities including nitrogen oxides and/or oxygen. The process comprises passing the gas over a sulphur-resistant hydrogenation catalyst at a temperature of from 120 DEG C. to 250 DEG C. and at a pressure of from 0.5 to 250 bar to remove the nitrogen oxides and/or oxygen therefrom while substantially avoiding hydrogen cyanide removal. The gas may be obtained from a Koppers-Totzek gasifier and may be used for the production of ammonia after further purification. The sulphur-resistant catalyst may be a nickel molybdate or cobalt molybdate catalyst or a metal from Group VI and/or Group VIII of the Periodic Table.