PROCESS FOR PURIFYING AN INDUSTRIAL GAS CONTAINING SULPHUROUS AN HYDRIDE OR SULPHURIC ANHYDRIDE WITH THE PRODUCTION OF ELEMENTAL SULPHUR

摘要

1397145 Gas purification; sulphur INSTITUT FRANCAIS DU PETROLE 10 Oct 1972 [11 Oct 1971] 46706/72 Heading C1A Gas containing sulphur dioxide or hydrogen sulphide is purified (a) by contact with an aqueous solution of sodium carbonate or in the case of hydrogen sulphide with an aqueous solution of sodium carbonate and sodium hydroxide to convert the sulphur compounds into sodium sulphite or sulphide, (b) contacting the spent absorbent with aqueous ammonium hydrogen carbonate or a gaseous mixture of CO 2 and NH 3 to form NaHCO 3 which is separated and heated to form CO 2 and Na 2 CO 3 which latter is recycled to step (a) and (c) reacting the remaining solution or its thermal decomposition products with H 2 S when it contains sulphite or SO 2 when it contains sulphide to produce sulphur which is separated and the ammonia and CO 2 produced is recycled to form the precipitating agent of step (b). Step (a) may be carried out at temperatures from 50‹ to 80‹ C. and step (b) from 0‹ to 50‹ C. The gas stream to be purified may also contain sulphur trioxide. The solution resulting from step (a) may also be treated with H 2 S prior to reaction with NH 3 and CO 2 . The third step (step c) is preferably carried out at 90-170‹ C. in the presence of a glycol, a glycol ester or ether, a polyalkylene glycol, a polyalkylene glycol ester or ether, a heavy alcohol, a phosphoric ester, N-methyl pyrrolidone or liquid sulphur.