Method for reducing sulfur compounds in sulfur plant effluent

Abstract

In the recovery of sulfur from hydrogen sulfide-containing gases wherein the first of a series of reactors is operated under conventional Claus conditions, one or more of the remaining catalytic reactors in the sulfur plant are operated at temperatures of the order of from about 250° to about 400°F. whereby free sulfur is deposited on the catalyst, regeneration of such catalyst is effected by heating a portion of the first reactor-condenser effluent to 500°-700°F. and flowing the resultant hot gas through the deactivated catalyst bed to vaporize free sulfur therefrom and regenerate the catalyst. Before placing the freshly regenerated catalyst bed back on stream, it is cooled with unheated first reactor-condenser effluent to a temperature of from about 250° to about 400° F. Thereafter the above cycle is repeated.

We claim: .[.1. In a process for removing hydrogen sulfide and sulfur dioxide in the condenser effluent from a Claus catalytic reaction zone wherein said effluent is contacted with a catalyst in a second reaction zone, said catalyst being capable of promoting the reaction between hydrogen sulfide and sulfur dioxide at a temperature at which the sulfur formed is deposited on said catalyst and in subsequent steps the catalyst is regenerated by the use of hot gas at a temperature of about 450°-700° F. to remove the deposited sulfur, the improvement comprising: 
     
        gas stream (1) and said effluent. .Iaddend..Iadd. 5.  In a process for removing hydrogen sulfide and sulfur dioxide in the condenser effluent from a Claus catalytic reaction zone, the improvement comprising: (1) introducing said condenser effluent into one of two catalytic reaction zones at an inlet temperature of 250° to 400°F whereby free sulfur is deposited on the surface of the catalyst therein, and continuing the deposition of sulfur on the catalyst until the amount of hydrogen sulfide and sulfur dioxide in the effluent from said one of said zones reaches a preset allowable limit,   (2) thereafter switching the flow of said condenser effluent to the other of said catalytic reaction zones under the conditions of Step (1),   (3) effecting removal of said deposit from the catalyst in said one of said zones by contacting the catalyst therein at a temperature of from about 450° to 700°F with gas stream (1) produced in Step (4),   (4) cooling the effluent from said one of said zones to obtain liquid sulfur and gas stream (1),   (5) cooling the hot, freshly regenerated catalyst in said one of said zones by flowing gas stream (1) therethrough,   (6) and thereafter subjecting the catalyst in said other of said zones to the conditions of Steps (3) through (5) in sequence while equalizing the system pressure in Steps (1) through (6) by transfer of gas between cooled gas stream (1) and said effluent. .Iaddend. .Iadd. 6. Process of claim 5 in which the hot, freshly regenerated catalyst is cooled with gas stream (1) at a temperature of from about 250° to about 350°F. .Iaddend..Iadd. 7. The process of claim 5 in which the hot, freshly regenerated catalyst is cooled with gas stream (1) at a temperature of from about 250° to about 300°F. .Iaddend.