Patent ID: 6416725
Filing Date: 2002-07-09
Classification: B01D,C01B,D01F,Y02P

Abstract:
A method of processing a gas stream comprising hydrogen sulfide and carbon disulfide, which comprises:providing a two-stage gas-liquid contactor, contacting said gas stream with an aqueous solution of sodium hydroxide in a first stage of said gas-liquid contactor to dissolve hydrogen sulfide and carbon disulfide from said gas stream, contacting said gas stream with an aqueous solution of sodium hydroxide in a second stage of said gas-liquid contactor to dissolve residual hydrogen sulfide from said gas stream, removing a gas stream containing residual carbon disulfide and substantially free from hydrogen sulfide from the second stage of said gas-liquid contactor, removing aqueous sodium hydroxide solution from said first stage of said gas-liquid contactor and recycling the removed solution to contact the gas stream entering said first stage and repeating said removal and further contacting until a desired concentration of sodium bisulfide is provided in the aqueous sodium hydroxide solution in said first stage, removing aqueous sodium hydroxide solution from said second stage of said gas-liquid contactor and recycling the removed solution to contact the gas stream entering said second stage and repeating said removal and further contacting until said desired concentration of sodium bisulfide is provided in said aqueous sodium hydroxide solution in said first stage, removing the aqueous sodium bisulfide solution from the first stage, replacing the same by said aqueous sodium hydroxide solution from said second stage and replacing the second stage aqueous sodium hydroxide solution by fresh aqueous sodium hydroxide solution, heating the removed aqueous sodium bisulfide solution to form gaseous carbon disulfide and an aqueous solution of sodium bisulfide depleted of carbon disulfide, recovering the gaseous carbon disulfide, and recovering the resulting aqueous solution of sodium bisulfide.