Process for the removal of H2 S from fluid streams using a water soluble polymeric chelate of an oxidizing polyvalent metal

Claim 1

A cyclic process for the removal of H 2 S from a gas stream comprising H 2 S, which process comprises: (A) contacting the gas stream in a contacting zone with an aqueous reaction solution at between about 10° and 90° C. for a time sufficient to oxidize S = to elemental sulfur the reaction solution itself consisting of an amount of water-soluble organic polymeric chelate effective to oxidize the S= to elemental sulfur containing an oxidizing polyvalent metal selected from an organic polymeric chelate having a molecular weight of between about 1,000 and 500,000 daltons of the formula: (i) ##STR25## wherein X 1 in each polymer unit is independently selected from --H or from a substituent R-- selected from --CH 2 COOH, --CH 2 CH 2 COOH, --CH 2 --P(═O) (OH) 2 , or ##STR26## wherein R 1 and R 2 are each independently --CH 3 , --SO 3 H, --Cl, --H, or --COOH and n is an integer between about 5 and 20,000; (ii) ##STR27## wherein X 2 in each polymer unit is selected from --H or a substituent selected from --CH 2 CH(OH)CH 2 OH, --CH 2 CH(OH)CH 2 Cl or ##STR28## wherein R 3 , R 4 and R 5 are each independently selected from R as defined hereinabove, p is an integer between about 5 and 20,000; and q is an integer selected from 0, 1, 2, 3 or 4; (iii) ##STR29## wherein X 3 in each polymer unit is independently selected from --OH, --Cl or a substituent: ##STR30## wherein R 3 , R 4 and R 5 are as defined hereinabove; r is an integer between about 10 and 20,000, and s is an integer between about 1 and 4; (iv) ##STR31## wherein X 4 in each polymer unit is independently selected from --OH, --OCH 3 , --OCH 2 CH 3 or a substituent: ##STR32## wherein R 3 , R 4 and R 5 are as defined hereinabove, t is an integer between about 10 and 20,000; and x is an integer between 1 and 4; (v) ##STR33## wherein X 5 in each polymer unit is independently selected from --OH, --Cl or a substituent: ##STR34## wherein R 3 , R 4 and R 5 are as defined hereinabove; y is an integer between about 10 and 20,000, and z is an integer between about 1 and 4; (vi) ##STR35## wherein X 6 in each polymer unit is independently selected from --CH 2 CH(OH)CH 2 OH, --CH 2 CH(OH)CH 2 Cl, or ##STR36## wherein v is between about 10 to 10,000, a is 6, b is 1 to 4, c is 1 to 4; and R 3 , R 4 and R 5 are as defined hereinabove; (vii) ##STR37## wherein X 7 in each polymer unit is independently selected from --H or a substituent selected from --CH 2 CH(OH)CH 2 OH, --CH 2 CH(OH)CH 2 Cl, or ##STR38## wherein m is an integer from 1 to 4, g is between 10 and 10,000, q and R 3 , R 4 and R 5 are as defined hereinabove; or (viii) ##STR39## wherein X 8 , X 9 and X 10 in each polymer unit are each independently selected from --H or a substituent selected from --CH 2 CH(OH)CH 2 Cl, --CH 2 CH(OH)CH 2 OH, or ##STR40## q, R 3 , R 4 and R 5 are defined hereinabove, w is between about 10 and 10,000; or (ix) mixtures of polymeric chelates (i) to (viii); with the proviso that the overall ratio of --H, --OCH 3 , --OCH 2 CH 3 , --Cl, or --OH to substituent in each of X 1 , X 2 , X 3 , X 4 , X 5 , X 6 , X 7 , X 8 , X 9 or X 10 in each polymeric chelant (i to viii) hereinabove is between about 10/90 and 90/10; (B) separating the gas stream and the resulting aqueous phase containing sulfur and polymeric chelated-metal complex produced in step (A); (C) separating the sulfur from the aqueous phase separated in step (B); (D) treating the aqueous solution produced in step (C) by membrane separation means effective to remove water and other monomeric reaction products present having a molecular weight of less than 500 daltons from the aqueous solution; (E) contacting the concentrated aqueous solution produced in step (D) with an oxidizing agent under reaction conditions effective to oxidize the polyvalent metal in chelate form; and (F) recycling the concentrated aqueous solution from step (E) to the contacting zone of step (A).