Removal of hydrogen sulfide from gas streams

摘要

A method for removing hydrogen sulfide from a gas stream in a gas-liquid absorber apparatus having two separate absorption sections and utilizing a first absorber alkali solution stream that is a waste sodium carbonate source from a soda ash production facility and a second absorber alkali solution stream that is a process feed stream from a soda ash production facility. The method is particularly well suited for removing H2S from a CO2-containing gas stream generated in a soda ash production facility.

主权项

1. A method for removing hydrogen sulfide from a carbon dioxide gas stream in a soda ash production facility comprising introducing a H2S-contaminated carbon dioxide gas stream from a carbon dioxide stripping unit operation in a soda ash production facility containing at least 20 vol % CO2 into a gas absorption apparatus for sequential contact of the gas stream with a first absorber alkali stream in a first absorber section and with a second absorber alkali stream in a second absorber section, wherein the first absorber alkali stream is an aqueous alkali waste stream containing at least 1 wt. % Na2CO3 and solubilized impurities from the soda ash production facility and is contacted with the H2S-contaminated carbon dioxide gas stream in the first absorber section of the gas absorption apparatus in an amount sufficient to absorb a substantial amount of the H2S from the gas stream to produce a H2S-depleted carbon dioxide gas stream and a first absorber effluent stream containing the absorbed H2S, and wherein the second absorber alkali stream is an aqueous process stream containing at least 1 wt. % Na2CO3 from the soda ash production facility and is contacted with the H2S-depleted carbon dioxide gas stream in the second absorber section of the gas absorption apparatus in an amount sufficient to absorb a substantial amount of the residual H2S in the H2S-depleted carbon dioxide gas stream from the gas stream to produce a purified carbon dioxide gas stream and a second absorber effluent stream containing the absorbed residual H2S; withdrawing the first absorber effluent stream containing absorbed H2S and solubilized impurities from the first absorber section; withdrawing the second absorber effluent stream containing absorbed residual H2S from the second absorber section and thereafter utilizing the second absorber effluent stream in the soda ash production facility, for further processing for recovery of its solubilized Na2CO3 values; and withdrawing the purified carbon dioxide gas stream from the gas absorption apparatus.