Abstract Discharge of sulfur compounds into the air in the tailgas from a Claus plant is substantially eliminated by first burning the acid gas delivered thereto with less than an amount of oxygen required to oxidize one-third of the H2S supplied so that the ratio of H2S to SO2 in the hot tailgas is greater than normal and preferably of the order of about 4:1 up to about 10:1. The hot tailgas is next quenched with water to lower the underflow from the quench up to about 130* F. or lower thereby condensing sulfur to solid form and water vapor to liquid thus producing a gaseous effluent substantially devoid of SO2 since the excess of H2S with respect to SO2 in the tailgas drives the reaction therebetween to substantial completion. Sulfur in solid form is recovered from the underflow effluent while the overhead quench effluent is treated with a regenerable quinone absorption agent to remove residual sulfur compounds therefrom. Sulfur is removed from the absorption agent in conjunction with regeneration thereof and then combined with the sulfur removed from the water quench underflow.
A process as set forth in claim 1 whereas is included the step of contacting the gaseous constituents remaining from said quench step with an aqueous alkaline solution of at least one salt of anthraquinone disulfonic acid.
Claim 2
Dependent Claim
55 words
A process as set forth in claim 1 wherein is included the step of contacting the gaseous constituents remaining from said quench step with an aqueous alkaline solution of at least one salt of anthraquinone disulfonic acid and a substance selected from the group consisting of ortho-, meta- and pyrovanadates of ammonia and alkali metals.
Claim 3
Dependent Claim
40 words
A process as set forth in claim 1 wherein is included the step of contacting the gaseous constituents remaining from said quench step with an aqueous alkaline solution of at least one salt of anthraquinone disulfonic acid and sodium metavanadate.
Claim 4
Dependent Claim
32 words
A process as set forth in claim 1 wherein is included the step of contacting the gaseous constituents remaining from said quench step with an aqueous alkaline solution containing 1,4-naphthaquinone, 2-sulfonate sodium.
Claim 5
Dependent Claim
55 words
A process as set forth in claim 1 wherein is included the steps of quenching the tailgas from said Claus plant with cooling water and treating the cooling water separated from the quench step underflow effluent to remove any H2S, SO2 and S contained therein to permit reuse thereof as quench waTer for said tailgas.
Claim 6
Dependent Claim
38 words
A process as set forth in claim 6 wherein is included the step of passing the cooling water through an evaporative cooling zone prior to reuse thereof to remove at least a part of the heat load therefrom.
Claim 7
Dependent Claim
44 words
A process as set forth in claim 1 wherein is included the step of quenching the hot tailgas from the Claus plant with sufficient cooling liquid at a temperature to lower the underflow effluent therefrom to a temperature of about 100* - 110* F.