Method and Apparatus for Generating Hydrogen

Abstract

Method and apparatus for generating hydrogen from a fuel comprising an endothermically decomposable compound, preferably methanol, and optionally comprising water. A catalyst is preferably used to decompose the methanol into hydrogen and CO. The catalyst preferably has low selectivity for reacting the CO and water to form CO 2 and hydrogen. A permselective membrane, preferably cleaned by the water, is used to separate the hydrogen. The retentate has fuel value and is reacted or otherwise burned in order to provide heat for the decomposition reaction.

1 . An apparatus for producing hydrogen, the apparatus comprising:
 a reactor comprising a catalyst, said catalyst being selective for decomposing an endothermically decomposable compound to form hydrogen and a primary byproduct having a heat value;   a permselective membrane for separating the hydrogen from said primary byproduct; and   a burner for oxidizing said primary byproduct, said burner in thermal contact with said reactor;   wherein said burner provides sufficient heat to said reactor to drive decomposition of said compound.   
     
     
         2 . The apparatus of  claim 1  wherein said endothermically decomposable compound comprises methanol. 
     
     
         3 . The apparatus of  claim 1  wherein said fuel comprises up to approximately 25 wt % water. 
     
     
         4 . The apparatus of  claim 3  wherein said fuel comprises up to approximately 10 wt % water. 
     
     
         5 . The apparatus of  claim 4  wherein said fuel comprises approximately 5 wt % water and approximately 95 wt % methanol. 
     
     
         6 . The device of  claim 3  wherein the water cleans said permselective membrane. 
     
     
         7 . The device of  claim 1  wherein said catalyst is selective for methanol decomposition over a reaction selected from the group consisting of a water-gas-shift reaction, formation of methane, formation of methyl formate, and formation of dimethyl ether. 
     
     
         8 . The apparatus of  claim 1  wherein said primary byproduct comprises carbon monoxide. 
     
     
         9 . The apparatus of  claim 1  wherein said reactor, said membrane, and said burner are thermally integrated within a single module. 
     
     
         10 . The apparatus of  claim 1  further comprising a variable pressure and/or variable flow rate pressurized fuel source. 
     
     
         11 . The apparatus of  claim 1  further comprising a heat exchanger. 
     
     
         12 . The apparatus of  claim 1  further comprising a pressure regulator for regulating a pressure of the separated hydrogen. 
     
     
         13 . The apparatus of  claim 1  further comprising a pressure regulator for regulating a pressure of said separated primary byproduct. 
     
     
         14 . The apparatus of  claim 1  comprising a compressed air source for supplying an oxidizing gas to said burner. 
     
     
         15 . The apparatus of  claim 1  further comprising a venturi ejector for drawing air into said burner together with said separated primary byproduct. 
     
     
         16 . The apparatus of  claim 15  wherein said venture ejector comprises an orifice restrictor disposed in a nozzle. 
     
     
         17 . The apparatus of  claim 16  wherein said orifice restrictor restricts flow of said separated primary byproduct, thereby increasing a back-pressure in said reactor. 
     
     
         18 . The apparatus of  claim 15  wherein said venture ejector is configured so that expansion of pressurized separated primary byproduct provides force to drive the air. 
     
     
         19 . An electric power source that comprises a fuel cell and the apparatus of  claim 1 .