Low temperature autothermal steam reformation of methane in a fluidized bed

Abstract

A process of producing hydrogen by autothermal steam reformation of a hydrocarbon comprises the steps of providing a reactor vessel having a fluidized catalyst bed, introducing steam and a gaseous hydrocarbon, introducing oxygen, maintaining the bed temperature below the spontaneous combustion temperature of the hydrocarbon in a fluidized bed, and withdrawing hydrogen by means of a perm selective membrane. An apparatus for producing hydrogen comprises a reactor vessel, steam and hydrocarbon inlets, an oxygen inlet, a fluidized bed of catalyst within the reactor vessel and a perm selective membrane for withdrawing hydrogen from the reactor.

What is claimed:  
     
         1 . A fluidized bed reactor for producing and separating hydrogen comprising: 
 (a) a reactor vessel comprising a closed reaction chamber having a reaction zone and a freeboard zone, said reaction zone comprising a bed of a suitable fluidized particle catalyst;    (b) means for pre-heating the reaction zone;    (c) means for introducing steam and a gaseous hydrocarbon into the reaction zone;    (d) an oxygen inlet for introducing oxygen into the reaction zone; and    (e) means for separating hydrogen and withdrawing hydrogen from the reaction chamber.    
     
     
         2 . The reactor of  claim 1  wherein reaction chamber comprises a perforated distributor plate forming a floor of the chamber and said oxygen inlet is above the distributor plate.  
     
     
         3 . The reactor of  claim 2  wherein the oxygen inlet is a sparging tube.  
     
     
         4 . The reactor of  claim 1  further comprising means for controlling the heating means in response to autothermic or the absence of autothermic conditions within the reaction chamber.  
     
     
         5 . The reactor of  claim 1  wherein the hydrogen separation means is a tubular membrane within the reaction chamber having a bore in fluid communication with an outlet outside the reaction chamber.  
     
     
         6 . The reactor of  claim 5  wherein the tubular membrane is metallic and comprised of one of palladium, niobium, tantalum or any suitable alloy or combination thereof.  
     
     
         7 . The reactor of  claim 6  wherein the tubular membrane is comprised of niobium and/or tantalum having a palladium coating.  
     
     
         8 . The reactor of  claim 7  wherein the tubular membrane has an external surface and an internal surface and both surfaces are coated with palladium.  
     
     
         9 . The reactor of  claim 8  wherein the tubular membrane is internally reinforced to resist external crushing forces.  
     
     
         10 . The reactor of  claim 5  wherein the tubular membrane is U-shaped and defines a bore in fluid communication with an outlet and an inlet outside the reaction chamber.  
     
     
         11 . A fluidized bed reactor for producing and separating hydrogen comprising: 
 (a) a reactor vessel comprising a closed reaction chamber having a reaction zone and a freeboard zone, said reaction zone comprising a bed of a suitable fluidized particulate catalyst;    (b) a reaction zone pre-heater;    (c) a steam inlet and a gaseous hydrocarbon inlet into the reaction zone;    (d) an oxygen inlet for introducing oxygen into the reaction zone; and    (e) a tubular membrane for separating and withdrawing hydrogen from the reaction chamber.    
     
     
         12 . The reactor of  claim 11  wherein reaction chamber comprises a perforated distributor plate forming a floor of the chamber and said oxygen inlet is above the distributor plate.  
     
     
         13 . The reactor of  claim 12  wherein the oxygen inlet is a sparging tube.  
     
     
         14 . The reactor of  claim 11  further comprising means for controlling the heating means in response to autothermic or the absence of autothermic conditions within the reaction chamber.  
     
     
         15 . The reactor of  claim 11  wherein the tubular membrane is metallic and comprised of one of palladium, niobium, tantalum or any suitable alloy or combination thereof.  
     
     
         16 . The reactor of  claim 15  wherein the tubular membrane is comprised of niobium and/or tantalum having a palladium coating.  
     
     
         17 . The reactor of  claim 16  wherein the tubular membrane has an external surface and an internal surface and both surfaces are coated with palladium.  
     
     
         18 . The reactor of  claim 17  wherein the tubular membrane is internally reinforced to resist external crushing forces.  
     
     
         19 . The reactor of  claim 18  wherein the tubular membrane is U-shaped and defines a bore in fluid communication with an outlet and an inlet outside the reaction chamber.