Cleaning coke oven gas by multistage method - in which hydrogen sulphide, hydrogen cyanide and ammonia are removed and no following hydrogen sulphide wash is needed

摘要

This method of cleaning coke-oven gas consists of the scrubbing out of, at least, H2S, HCN and NH3 in the following stages: (a) absorption of the H2S, HCN and NH3 by an alkaline redox soln.; (b) treatment of the redox soln. in an oxidn. unit ("Oxideur") with air, and sepn. of sulphur: (c) absorption of the NH3 remaining after stage (a) by means of an aq. circulating washing-soln.; (d) desorption of the NH3 from the aq. washing-soln. by means of steam and if necessary the outgoing air from the oxidn. unit; and (e) the introduction of the practically H2S-free air and NH3 from the oxidn. unit (stage b) and of the acid gas from the desorption (stage c) in a pref. multi-stage NH3 combustion system and/or a catalytic NH3 cracking system. Several variants are claimed. USE/ADVANTAGE - This development of an existing method of cleaning coke-oven gas obviates the need for a following H2S wash.