Production of Hydrogen Gas From Sulfur-Containing Compounds

Abstract

The described invention is a process for producing hydrogen gas comprising (a) combusting sulfur (S) or hydrogen sulfide (H 2 S) with oxygen (O 2 ) to obtain sulfur dioxide (SO 2 ) and water (H 2 O), plus heat; (b) adding water to the product of (a) to obtain a sulfurous acid solution (H 2 SO 3 and H 2 O); (c) applying electrical current to the sulfurous acid solution of (b) to obtain sulfuric acid (H 2 SO 4 ) and hydrogen gas (H 2 ); and, (d) using gas-liquid separation to separate the sulfuric acid from the hydrogen gas to obtain separated components of the sulfuric acid and the hydrogen gas; and, wherein the heat generated in (a) is used to generate at least a portion of the electricity for the electrical current of (c).

1 . A process for producing hydrogen gas comprising:
 a. combusting sulfur (S) or hydrogen sulfide (H 2 S) with oxygen to obtain sulfur dioxide (SO 2 ) and water (H 2 O), plus heat;   b. adding water to the product of (a) to obtain a sulfurous acid solution (H 2 SO 3  and H 2 O);   c. applying electrical current to the sulfurous acid solution of (b) to obtain sulfuric acid (H 2 SO 4 ) and hydrogen gas (H 2 );   d. using gas-liquid separation to separate the sulfuric acid from the hydrogen gas   to obtain separated components of the sulfuric acid and the hydrogen gas; and,   
     wherein the heat generated in (a) is used to generate at least a portion of the electricity for the electrical current of (c). 
   
   
       2 . The process of  claim 1  where said oxygen is provided by introduction of air. 
   
   
       3 . The process of  claim 1  wherein said hydrogen sulfide in (a) is provided as a raw acid gas from the production of petrochemical products, said gas comprising hydrogen sulfide and carbon dioxide (CO 2 ), and optionally, gaseous hydrocarbons. 
   
   
       4 . The process of  claim 3  wherein before said water in (b) is added, the product sulfur dioxide is separated from the other gaseous combustion products and unreacted gases. 
   
   
       5 . The process of  claim 1  wherein said sulfur in (a) is comprised in a combustible, carbon-containing compound, or mixture of compounds. 
   
   
       6 . The process of  claim 5  wherein said combustible, carbon-containing compound or compounds is selected from one or more of hard coal, soft coal, or coke products. 
   
   
       7 . The process of  claim 5  wherein said combustible, carbon-containing compound or compounds is a sulfur-laden heavy oil or bitumen. 
   
   
       8 . The process of  claim 1 , wherein the electrical current is applied using a voltage below 0.50 volts. 
   
   
       9 . The process of  claim 1 , further comprising removing the sulfuric acid from the process. 
   
   
       10 . The process of  claim 1 , wherein step (b) is operated at a temperature of about 125° F. (about 52° C.). 
   
   
       11 . A system for producing hydrogen gas comprising:
 a. an acid gas stream containing hydrogen sulfide;   b. an air stream;   c. a burner configured to burn the acid gas stream and air stream and produce a product stream having at least sulfur dioxide, water, and heat;   d. a boiler unit operatively connected to the product stream of the burner and configured to capture heat from the burner, and generate at least a steam stream and an exhaust gas stream having at least SO 2 ;   e. an SO 2  separation unit operatively connected to the exhaust gas stream of the boiler unit and configured to remove SO 2  from the exhaust gas stream and generate an SO 2  exit stream; and   f. an electrolytic cell operatively connected to the SO 2  exit stream and configured to produce hydrogen gas (H 2 ).   
   
   
       12 . The system of  claim 11 , further comprising: an electrical generator driven by at least a portion of the steam stream and configured to provide electricity to the electrolytic cell. 
   
   
       13 . The system of  claim 11 , wherein the SO 2  separation unit is a solvent based SO 2  separation unit. 
   
   
       14 . The system of  claim 11 , further comprising a water inlet stream configured to provide water to the electrolytic cell. 
   
   
       15 . The system of  claim 11 , further comprising a regeneration unit operatively connected to the SO 2  separation unit and configured to produce at least one water stream, wherein at least a portion of the steam stream is supplied to the regeneration unit and at least a portion of the water stream is supplied to the boiler unit. 
   
   
       16 . The system of  claim 11 , further comprising:
 a. a sulfuric acid purge stream configured to take off at least sulfuric acid from the SO 2  separation unit; and   b. a sulfuric acid exit stream configured to remove sulfuric acid from the electrolytic cell.   
   
   
       17 . The system of  claim 11 , wherein the SO 2  separation unit is configured to operate at a temperature of about 100° F. (about 38° C.). 
   
   
       18 . The system of  claim 15 , wherein the regeneration unit is configured to operate at a temperature of about 300° F. (about 149° C.).