Process for the removal of sulfur compounds from gas streams

A method of reducing the amount of sulfur compounds in an incoming gas stream, wherein said sulfur compounds comprise one or more of COS, CS2, SO2, and H2S, comprising the steps of:

• i. providing a guard bed containing an hydrolysis catalyst for the conversion of COS and CS2 to H2S and the reduction of SO2 to elemental sulfur;
• ii. flowing said incoming gas stream through said guard bed, to produce an effluent stream;
• iii. providing an acidic gas removal unit comprising an absorbent suitable for acidic gas absorption;
• iv. flowing said effluent stream from the guard bed over said absorbent in the acidic gas removal unit to produce a stream that is free of acidic gases, said absorbent becoming rich in acidic gases,
• v. applying an acid gas desorption condition to said acidic-gas rich absorbent to desorb acid gases therefrom and to produce an acidic gas stream rich in acidic gases and containing H2S;
• vi. introducing oxygen to said acidic gas-rich stream;
• vii. providing a direct oxidation vessel containing a catalytic reaction zone comprising a catalyst suitable for catalyzing the oxidation of the H2S to sulfur wherein the temperature of the reaction zone is at or above the sulfur dew point at the reaction pressure;
• viii. flowing said acidic gas-rich stream over said catalyst to produce a processed stream comprising a reduced level of said sulfur compounds when compared to the acidic gas-rich stream;
• and
• ix. recycling at least a portion of said processed stream back to said guard bed and acidic gas removal unit.

A system for of reducing the amount of sulfur compounds in an incoming gas stream and producing a CO2 stream of high purity, such system comprising:

• i. a guard bed containing an hydrolysis catalyst, said hydrolysis catalyst adapted for the conversion of COS and CS2 to H2S and the reduction of SO2 to elemental sulfur, and optionally also an RSH adsorbent suitable for RSH removal, said guard bed adapted to receive said incoming stream and produce an effluent stream after passage of said incoming stream through said guard bed;
• ii. an acidic gas removal unit comprising an absorbent suitable for acidic gas absorption, adapted to receive said effluent stream and produce a produced stream that is free of acidic gases, said absorbent becoming rich in acidic gases;
• iii. said absorbent adapted, when said having heat applied thereto, to produce an acidic gas stream rich in acidic gases;
• iv. oxygen supply means, adapted to supply oxygen to said acidic gas stream;
• v. a direct oxidation vessel, adapted to receive said acidic stream rich in acidic gases and oxygen, and containing a catalytic reaction zone comprising a catalyst suitable for catalyzing the oxidation of the H2S to sulfur wherein the temperature of the reaction zone is at or above the sulfur dew point at the reaction pressure, and to produce a processed stream comprising a reduced level of said sulfur compounds when compared to the incoming acidic stream;
• and
• vi. recycling piping to recycle at least a portion of said processed stream back to said guard bed and acidic gas removal unit.