Patent ID: 8398848

Claim:
A process for desuifurizing a sulfur-containing hydrocarbon stream, comprising: a) contacting a sulfur-containing hydrocarbon stream with an API gravity of less than about 40 with an alkali metal hydroxide in a first reaction zone, thereby producing a desulfurized hydrocarbon/spent alkali metal reagent stream; b) conducting the desulfurized hydrocarbon/spent alkali metal reagent stream to a first separation zone, wherein at least a portion of the desulfurized hydrocarbons are separated from the spent alkali metal reagents, thereby producing a desulfurized hydrocarbon product stream; c) conducting at least a portion of the spent alkali metal reagents to a second reaction zone, wherein the spent alkali metal reagents are contacted with a copper metal reagent, and wherein the spent alkali metal reagents are comprised of alkali metal hydrosulfides, and at least a portion of the alkali metal hydrosulfides are converted to regenerated alkali metal hydroxides and at least a portion of the copper metal reagent is converted to copper sulfides, thereby producing a desulfurized alkali metal stream comprised of regenerated alkali metal hydroxides and copper sulfides; d) conducting at least a portion of the desulfurized alkali metal stream to a second separation zone, wherein at least a portion of the copper sulfides are separated from the regenerated alkali metal hydroxides; e) conducting at least a portion of the regenerated alkali metal hydroxides to the first reaction zone as a regenerated alkali metal hydroxide stream; f) conducting at least a portion of the separated copper sulfides to a first regeneration zone, wherein the separated copper sulfides are contacted with a hydrogen-containing stream at a temperature from about 1000 to about 2000° F., thereby converting at least a portion of the separated copper sulfides to regenerated copper metal; and g) conducting at least a portion of the regenerated copper metal to the second reaction zone; wherein the regenerated alkali metal hydroxide stream contains carbonates and at least a portion of the regenerated alkali metal hydroxide stream is subjected to a carbonate removal step prior to returning the regenerated alkali metal hydroxide stream to the first reaction zone; and the carbonate removal step is comprised of contacting the regenerated alkali metal hydroxide stream with an aqueous suspension of calcium oxide and calcium hydroxide.