Process for removing hydrogen sulfide from gas streams which include or are supplemented with sulfur dioxide, by scrubbing with a nonaqueous sorbent

A process for removing H2S from a gaseous stream, by the steps of:

• (a) flowing the gaseous stream through an absorber vessel whereat said stream is contacted with a sorbing liquor comprising a nonaqueous solvent containing dissolved sulfur, a base consisting essentially of a tertiary amine having sufficient strength and concentration to drive the reaction between H2S sorbed by said liquor and said dissolved sulfur to form a nonvolatile polysulfide which is soluble in the sorbing liquor, and a solubilizing agent for maintaining the solubility of polysulfide intermediates which may otherwise separate during the process;
• (b) converting the dissolved nonvolatile polysulfide in said sorbing liquor to sulfur which remains dissolved in said liquor by contacting the liquor with an oxidizing gas comprising sulfur dioxide;
• (c) cooling said sorbing liquor following said oxidation of said polysulfide to a temperature at which the liquor is at or above saturation with respect to said dissolved sulfur;
• (d) converting at least part of the dissolved sulfur in the liquor from step (c) to solid particulate sulfur at a point downstream of the absorber vessel;
• and
• (e) separating said solid sulfur from step (d) from the liquor.