GB743172A - Process for the dry purification of sulphur-containing gases - Google Patents

Abstract

Sulphur or its compounds are separated and recovered from sulphur-containing gases by passing the gases at 100 to 300 DEG C. over a fixing agent comprising finely divided copper or an oxide thereof incorporated with an aluminous carrier substantially free from silica and thereafter regenerating the spent fixing agent by heating to 350 to 850 DEG C. and submitting it to a stream of air followed by a stream of hydrocarbon or carbon monoxide containing gas whereby the copper sulphur compound of the spent fixing agent is first oxidized with evolution of half of the sulphur as sulphur dioxide and thereafter the remaining compound is reduced to copper or a copper oxide with evolution of sulphur dioxide or sulphur carbonyl according to the nature of the reducing gas used. If the gases to be purified are of an oxidising character the regeneration of the spent fixing agent may be effected with a stream of hydrogen or carbon monoxide without first treating the spent agent with an oxidizing gas. The sulphur dioxide or sulphur carbonyl obtained during regeneration may be treated to produce elemental sulphur or other sulphur compounds. A chromic acid promoter may be incorporated in the carrier and substances assisting sintering of the carrier such as aluminium sulphide or magnesium carbonate may also be incorporated. The fixing agent may be prepared by incorporating a solution of a copper salt such as the sulphate or nitrate, or finely divided cement copper or copper oxide with a fine powder of dry hydrated alumina or alumina gel, adding sufficient water to form a stiff dough and kilning the resulting mass if desired after shaping at a temperature below 400 DEG C. to dehydrate. The kilning may also be effected at below 400 DEG C. using a stream of gas containing hydrogen sulphide thereby transforming the copper to copper sulphide, basic sulphide or oxysulphide and thereafter submitting the fixing agent to the regeneration process above referred to of oxidation followed by reduction before employment to remove sulphur from gases. The copper content of the fixing agent may be from 2 to 25 per cent.