GB1148756A - Process for the removal of hydrogen sulphide from natural gases - Google Patents

Abstract

1,148,756. Sulphur. B. GRUETER. 11 June, 1966, No. 26122/66. Heading C1A. [Also in Divisions B1 and C5] Hydrogen sulphide and mercaptans are removed from hydrocarbon-containing gas streams, especially from natural gas which also comprises methane, nitrogen and carbon dioxide, by pressure washing with a C 1-5 -trialkyl phosphate at temperatures up to 40‹ C., the ester being subsequently regenerated by depressurization in one or more stages, preferably with heating to 50-150‹ C. The washing is suitably performed at pressures of 40-80 atmospheres and depressurization may be effected in two stages. The preferred regeneration temperature is 100‹C., and regeneration may be assisted by passing a current of an inert or purified gas through the liquid. In one embodiment, especially suitable where the H 2 S content is high a natural gas stream is pressure washed and then passed through a bed of Type 5A molecular sieve to complete its purification. Part of the purified stream is used to regenerate an exhausted bed of molecular sieve, the effluent stream therefrom being recycled with the crude gas stream. In a second embodiment, suitable for use with a lower H 2 S content, the natural gas stream is purified by passage through a molecular sieve bed. Part of the purified effluent stream is passed through an exhausted second bed to regenerate it, and the effluent therefrom, of high sulphur content, is passed through a pressure wash before being recycled with the feed stream. The regeneration temperature for the molecular sieve bed is at least 200‹ C., and is preferably 250-400‹C. The sulphurcontaining gas stream obtained by regenerating the washing agent may be processed in a Claus plant to give elemental sulphur.