Patent ID: 8568679

Claim:
A process for removing sulfur from a fuel gas stream to a hydrogen sulfide concentration of less than 10 ppmv, said fuel gas stream comprising a carbon dioxide concentration in the range of from 1 ppmv to 3 vol %, a light olefin concentration in the range of from 0.5 vol % to 40 vol %, and an organic sulfur compound concentration in the range of from 40 ppmv to 5000 ppmv, wherein said process comprises: (a) introducing said fuel gas stream into a hydrotreater reactor containing a hydrotreating catalyst, wherein said fuel gas stream is contacted under hydrodesulfurization process conditions with said hydrotreating catalyst, wherein said hydrodesulfurization process conditions include a hydrodesulfurization contacting temperature in the range of from 230° C. to 480° C., a hydrodesulfurization contacting pressure in the range of from 30 psig to 600 psig, and a hydrodesulfurization GHSV that is in the range of from 0.01 hr −1 to 6000 hr −1 , and yielding from said hydrotreater reactor a hydrotreated fuel gas containing H 2 S and a COS concentration in the range of from 1 ppmv to 1.5 vol %; (b) introducing said hydrotreated fuel gas into a hydrolysis reactor containing a hydrolysis catalyst, which catalyst has a total pore volume in the range of from 0.3 cc/gram to 1.5 cc/gram, and a low macroporosity, with the total pore volume in macropores having a pore diameter of greater than 750 angstroms of less than 0.2 cc/gram, wherein the hydrolysis process conditions in said hydrolysis reactor include a hydrolysis reactor inlet temperature in the range of from 75° C. to 265° C., a hydrolysis contacting pressure in the range of from 30 psig to 600 psig and a hydrolysis GHSV that is in the range of from 0.01 hr −1 to 6000 hr −1 , wherein said hydrotreated fuel gas is contacted under said hydrolysis process conditions with said hydrolysis catalyst thereby converting COS to hydrogen sulfide, and yielding from said hydrolysis reactor a hydrolysis reactor effluent having a reduced COS concentration of less than 10 ppmv; (c) treating said hydrolysis reactor effluent in an absorption unit employing an amine absorbent to remove hydrogen sulfide, yielding a treated fuel gas stream having less than 10 ppmv H 2 S; and (d) diluting the light olefin-containing fuel gas stream in step (a) with a portion of the treated fuel gas from step (c) to help control the temperature of the hydrotreater reactor to avoid problems attributable to the olefin hydrogenation reaction.