System for generating h2s in an alkaline medium and method of using the same

Abstract

Method of producing hydrogen sulfide in an alkaline environment. A mixture having a sodium salt, elemental sulfur (S) and water is added to a reactor for the purpose of generating hydrogen sulfide (H2S) gas as the main product and sodium sulfate (Na2SO4) as a byproduct.

What is claimed is: 
     
         1 . A method for producing hydrogen sulfide (H 2 S) gas, the method comprising:
 placing elemental sulfur and a sodium salt solution comprising a sodium salt in water in a reaction vessel;   reacting the elemental sulfur with the sodium salt solution to form hydrogen sulfide (H 2 S) and sodium sulfate (Na 2 SO 4 );   removing the formed Na 2 SO 4  from the reaction vessel;   crystallizing the Na 2 SO 4  using a crystallizer;   reducing the crystallized Na 2 SO 4  to produce Na 2 S;   forming a Na 2 S solution with the produced Na 2 S;   placing elemental sulfur and the Na 2 S solution in the reaction vessel; and   reacting the elemental sulfur with the Na 2 S solution to form hydrogen sulfide and sodium sulfate.   
     
     
         2 . The method of  claim 1 , wherein the reaction vessel is pressurized to a pressure ranging from about 500 psi to about 1500 psi and heated to a temperature ranging from about room temperature to about 400° C. 
     
     
         3 . The method of  claim 1 , wherein the reaction vessel is pressurized to a pressure ranging from about 500 psi to about 700 psi and heated to a temperature ranging from about 200° C. to about 300° C. 
     
     
         4 . The method of  claim 1 , further comprising:
 pressuring the reaction vessel to a pressure of about 600 psi; or   heating the reaction vessel to a temperature ranging from about 230° C. to about 240° C.   
     
     
         5 . The method of  claim 1 , further comprising agitating the elemental sulfur and the sodium salt solution in the reaction vessel. 
     
     
         6 . The method of  claim 1 , wherein the crystallized Na 2 SO 4  is reduced to produce Na 2 S by a carbothermal reduction system. 
     
     
         7 . The method of  claim 1 , further comprising reacting the formed hydrogen sulfide with an aqueous copper sulfate solution to form CuS for determining the effective yield of H 2 S. 
     
     
         8 . The method of  claim 1 , wherein the sodium salt is any one of sodium hydroxide (NaOH), sodium carbonate (Na 2 CO 3 ), sodium hydrogen sulfide (NaHS), and sodium sulfide (Na 2 S). 
     
     
         9 . The method of  claim 8 , wherein the sodium salt is NaOH or Na 2 S. 
     
     
         10 . The method of  claim 1 , further comprising:
 decomposing the hydrogen sulfide to produce hydrogen and elemental sulfur;   placing the produced elemental sulfur and a sodium salt solution comprising a sodium salt in water in the reaction vessel; and   reacting the produced elemental sulfur with the sodium salt solution to form hydrogen sulfide (H 2 S) and sodium sulfate (Na 2 SO 4 ).   
     
     
         11 . A system for producing hydrogen sulfide (H 2 S) gas and sodium sulfate (Na 2 SO 4 ), the system comprising:
 a reaction vessel;   a sulfur feed source fluidically coupled with the reaction vessel;   a sodium salt solution feed source fluidically coupled with the reaction vessel;   a storage container fluidically coupled with the reaction vessel for storage of produced H 2 S gas;   a heat exchanger fluidically coupled with the reaction vessel for cooling a solution containing the Na 2 SO 4  produced in the reaction vessel;   a crystallizer fluidically coupled with the heat exchanger for crystallizing the Na 2 SO 4 ;   a Na 2 SO 4  reduction system for reducing the crystallized Na 2 SO 4  to form liquid Na 2 S; and   a container fluidically coupled with the reduction system for forming an aqueous Na 2 S solution, the container also being fluidically coupled with the reaction vessel.   
     
     
         12 . The system of  claim 11 , wherein the reaction vessel is configured to be pressurized to a pressure ranging from about 500 psi to about 1500 psi and heated to a temperature ranging from about room temperature to about 400° C. 
     
     
         13 . The system of  claim 11 , wherein the reaction vessel is configured to be pressurized to a pressure ranging from about 500 psi to about 700 psi and heated to a temperature ranging from about 200° C. to about 300° C. 
     
     
         14 . The system of  claim 11 , wherein the reaction vessel is heated by an internal heating element. 
     
     
         15 . The system of  claim 11 , wherein the reaction vessel is configured for agitation or stirring of the contents within the reaction vessel. 
     
     
         16 . The system of  claim 11 , wherein the Na 2 SO 4  reduction system is a carbothermal reduction system. 
     
     
         17 . The system of  claim 11 , further comprising:
 a first pump between the sulfur feed source and the reaction vessel; and   a second pump between the sodium salt solution feed source and the reaction vessel.   
     
     
         18 . The system of  claim 11 , further comprising an H 2 S decomposition reactor fluidically coupled with the storage container for decomposing the H 2 S to produce hydrogen and elemental sulfur. 
     
     
         19 . The system of  claim 18 , further comprising:
 a hydrogen storage container fluidically coupled with the decomposition reactor for storing the produced hydrogen; and   a sulfur storage container coupled with the decomposition reactor for storing of the produced elemental sulfur and producing an aqueous sulfur solution therein.   
     
     
         20 . The system of  claim 19 , wherein the sulfur storage container is fluidically coupled with the reaction vessel.