Absorption of hydrogen sulfide and methyl mercaptan from dilute gas mixtures

Abstract

The absorption of hydrogen sulfide and methyl mercaptan by aqueous solutions of chlorine, sodium hydroxide, and chlorine plus sodium hydroxide was studied using a two-inch diameter absorption column packed with ¼ inch Intalox saddles. Absorption rates were noticeably affected by chemical reactions occurring in the aqueous chlorine and hydroxide media. These solutions were studied as a means of controlling sulfur-containing gas emissions from kraft paper mills. The absorption studies indicated that aqueous chlorine solutions at a pH above 12 were effective absorbents for hydrogen sulfide removal in absorption equipment designed to tolerate sulfur in suspension. The absorption of methyl mercaptan in aqueous chlorine solutions appeared to be impractical since dimethyl disulfide was apparently the only product formed and was stripped from the tower by the gas stream. Sodium hydroxide solution was an effective absorbent for both methyl mercaptan and hydrogen sulfide when hydroxide to sulfide or mercaptan feed ratios were greater than 1 or 1.8, respectively. The mercaptan absorption coefficient was approximately twice that for sulfide absorption. © 1966 Air & Waste Management Association.