| abstract |
In the removal of H 2 S and optionally CO 2 from a gas by contacting with a reactant solution containing an ion or a chelate of a polyvalent metal with formation of solid sulphur and reduced reactant, the presence of a C 4-1 -alkanol or C 4-22 -alkenol increases the crystal size of the sulphur. The solution may contain an absorbent selective for CO 2 . Regeneration of the reactant in aqueous solution with an oxygen-containing gas may produce a froth from which the sulphur is recovered by extraction with C 4-18- alkanols or C 4-20 - alkenols. Alternatively, the sulphur can be separated from aqueous solutions by extraction with C 4-15- alkanols. The presence of sodium thiocyanate, sodium dithionite, thiodiglycolic acid and/or 3,3-thio-dipropionic acid addresses degradation of the chelates. |