GB1218195A - Process for removing hydrogen sulphide from a gas stream and converting it to elemental sulphur - Google Patents

Abstract

1,218,195. Sulphur. BLACK, SIVALLS & BRYSON Inc. 30 July, 1968 [28 Aug., 1967], No. 36341/68. Heading C1A. A process for removing hydrogen sulphide from a gas stream comprises: (a) absorbing H 2 S in an aqueous absorbent liquid; (b) stripping the absorbed H 2 S from the liquid with steam; (c) passing at least part of the stripped absorbent liquid through a heat recovery vessel to generate the steam; (d) burning part of the H 2 S from (b) to give SO 2 ; (e) cooling the hot gases by passage through the heat recovery vessel; (f) combining the cooled SO 2 with the remaining H 2 S and reacting in the presence of a catalyst to produce sulphur; and (g) cooling the sulphur by passage through the heat recovery vessel. In a modification, H 2 S from step (b) is burnt with <SP>1</SP>/ 3 the stoichiometric amount of air, the resulting mixture is cooled by passage through the heat recovery vessel, reacted in the presence of a catalyst, and the resulting sulphur cooled by passage through the heat recovery vessel. A second catalytic reaction stage may be used. In another modification, the cooled combustion mixture is divided into a first portion and a second portion, the first portion is combined with the remaining H 2 S, reacted in the presence of a catalyst, passed through the heat recovery vessel, the sulphur condensed and separated, the first portion and the second portion then being combined, reacted in the presence of a catalyst, and passed through the heat recovery vessel. The aqueous absorbent liquid preferably boils at a temperature well below the temperature at which sulphur condenses, and may be a 15- 20% solution of monoethanolamine in water.