Fuel Cell System and Method for Generating Electrical Energy Using a Fuel Cell System

Abstract

A fuel-cell system, particularly a fuel-cell system for a drive system of a motor vehicle, includes an autothermic reformer unit configured to generate hydrogen from a raw material. The hydrogen is used to operate a fuel-cell unit disposed downstream of the reformer unit. An oxidation device configured to convert carbon monoxide into carbon dioxide is disposed between the reformer unit and the fuel cell unit. A water injection device is disposed in the oxidation device and is configured to inject water into the oxidation device.

1 . A fuel-cell system, comprising: 
 a reformer unit configured to produce hydrogen from a raw material;    a fuel-cell unit disposed downstream of the reformer unit and operable in accordance with the hydrogen produced by the reformer unit;    an oxidation device configured to convert carbon monoxide into carbon dioxide and disposed between the reformer unit and the fuel-cell unit; and    a water-injection device disposed at the oxidation device and configured to inject water into the oxidation device.    
     
     
         2 . The fuel-cell system according to  claim 1 , wherein the fuel-cell system includes a drive system of a motor vehicle.  
     
     
         3 . The fuel-cell system according to  claim 1 , wherein the raw material includes a liquid raw material.  
     
     
         4 . The fuel-cell system according to  claim 1 , wherein the reformer unit includes a mixer configured to mix the raw material and an oxygen-containing substance.  
     
     
         5 . The fuel-cell system according to  claim 4 , wherein the oxygen-containing substance includes at least one of water and air.  
     
     
         6 . The fuel-cell system according to  claim 1 , further comprising a two-stage compressor configured to supply compressed air to at least one of a process gas between the oxidation device and the fuel-cell unit and a cathode of the fuel-cell unit.  
     
     
         7 . The fuel-cell system according to  claim 1 , further comprising a water separation device disposed in at least one of an exhaust-gas stream from a cathode of the fuel-cell unit, an exhaust-gas stream from an anode of the fuel-cell unit and a cleaned-gas stream from the oxidation unit, the water separating device being configured to separate the water contained in the corresponding gas and to supply the water to a water-storage device disposed upstream from the reformer unit.  
     
     
         8 . The fuel-cell system according to  claim 7 , wherein the water separation device includes a condenser.  
     
     
         9 . The fuel-cell system according to  claim 7 , further comprising a water circulation loop configured to cool at least one of the water separation device, the fuel-cell unit, air supplied to a cathode of the fuel-cell unit and air supplied to the reformer unit.  
     
     
         10 . The fuel-cell system according to  claim 1 , further comprising a catalytic burner configured to combust exhaust gas from an anode of the fuel-cell unit and to direct corresponding waste heat through a heat exchanger to the reformer unit.  
     
     
         11 . The fuel-cell system according to  claim 10 , wherein the catalytic burner is connected to a supply tank supplying the raw material.  
     
     
         12 . The fuel-cell system according to  claim 1 , further comprising: 
 an expander disposed in an exhaust-gas stream of a cathode of the fuel-cell unit; and    a compressor disposed in a supply-air stream of the fuel-cell unit;    wherein the expander and the compressor are arranged on a common shaft.    
     
     
         13 . The fuel-cell unit according to  claim 12 , wherein the compressor includes a two-stage compressor.  
     
     
         14 . The fuel-cell unit according to  claim 1 , wherein the raw material includes a hydrogen-containing substance.  
     
     
         15 . The fuel-cell unit according to  claim 14 , wherein the hydrogen-containing substance includes at least one of methanol and gasoline.  
     
     
         16 . A method for generating electrical energy using a fuel-cell system, comprising the steps of: 
 producing hydrogen from a raw material in a reforming process, a fuel-cell unit of the fuel-cell system being operable in accordance with the produced hydrogen;    oxidizing carbon monoxide into carbon dioxide after the reforming process and upstream of the fuel-cell unit; and    injecting water during the oxidizing step.    
     
     
         17 . The method according to  claim 16 , wherein the fuel-cell system includes a drive system of a motor vehicle.  
     
     
         18 . The method according to  claim 16 , wherein the water is injected as one of a vapor and an aerosol.  
     
     
         19 . The method according to  claim 16 , further comprising the step of supplying compressed air to at least one of a process gas between a carbon monoxide oxidizing unit and the fuel-cell unit and a cathode of the fuel-cell unit.  
     
     
         20 . The method according to claim  32 , further comprising the steps of: 
 separating water from at least one of a cathode-exhaust stream of the fuel-cell unit and an anode-exhaust stream of the fuel-cell unit; and    supplying the separated water to the reforming process.    
     
     
         21 . The method according to  claim 16 , further comprising the steps of: 
 burning an exhaust gas from an anode of the fuel-cell unit; and    supplying waste heat generated by the burning step to the reforming process.    
     
     
         22 . The method according to  claim 16 , further comprising the steps of: 
 burning the raw material; and    supplying heat energy generated by the raw material burning step to the reforming process.    
     
     
         23 . The method according to  claim 16 , wherein the raw material includes a hydrogen-containing substance.  
     
     
         24 . The method according to  claim 23 , wherein the hydrogen-containing substance includes at least one of methanol and gasoline.