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 - 24 . (canceled) 
     
     
         25 . 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;   an oxygen source configured to supply a first oxygen-containing substance to the oxidation device; and   a water-injection device disposed at the oxidation device;   wherein the fuel-cell system is arranged such that, during operation of the fuel-cell system, the water-injection device injects water into the oxidation device during each operation of the oxidation device for the conversion.   
     
     
         26 . The fuel-cell system according to  claim 25 , wherein the fuel-cell system includes a drive system of a motor vehicle. 
     
     
         27 . The fuel-cell system according to  claim 25 , wherein the raw material includes a liquid raw material. 
     
     
         28 . The fuel-cell system according to  claim 25 , wherein the reformer unit includes a mixer configured to mix the raw material and a second oxygen-containing substance. 
     
     
         29 . The fuel-cell system according to  claim 28 , wherein the second oxygen-containing substance includes at least one of water and air. 
     
     
         30 . The fuel-cell system according to  claim 25 , 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. 
     
     
         31 . The fuel-cell system according to  claim 25 , 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. 
     
     
         32 . The fuel-cell system according to  claim 31 , wherein the water separation device includes a condenser. 
     
     
         33 . The fuel-cell system according to  claim 31 , 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. 
     
     
         34 . The fuel-cell system according to  claim 25 , 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. 
     
     
         35 . The fuel-cell system according to  claim 34 , wherein the catalytic burner is connected to a supply tank supplying the raw material. 
     
     
         36 . The fuel-cell system according to  claim 25 , 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.   
     
     
         37 . The fuel-cell unit according to  claim 36 , wherein the compressor includes a two-stage compressor. 
     
     
         38 . The fuel-cell unit according to  claim 25 , wherein the raw material includes a hydrogen-containing substance. 
     
     
         39 . The fuel-cell unit according to  claim 38 , wherein the hydrogen-containing substance includes at least one of methanol and gasoline. 
     
     
         40 . The fuel-cell system according to  claim 25 , further comprising:
 a two-stage compressor including:
 a first stage via which compressed air at a first pressure is supplied to a cathode of the fuel-cell unit; and 
 a second stage via which compressed air at a second pressure higher than the first pressure is supplied to the reformer unit. 
   
     
     
         41 . The fuel-cell system according to  claim 25 , further comprising a water separation device disposed in a cleaned-gas stream from the oxidation unit, the water separation device being configured to separate the water contained in the corresponding gas and to supply the water to a water-storage device that supplies the water injected by the water-injection device into the oxidation device. 
     
     
         42 . The fuel-cell system according to  claim 25 , further comprising:
 a first water-storage device disposed in a first water circulation loop, the water-injection device obtaining the water injected into the oxidation device from the first water-storage device via circulation of the water of the first water-storage device through the first water circulation loop; and   at least one second water-storage device disposed in a second water circulation loop arranged for circulating the water of the at least one second water-storage device in proximity to elements of the fuel-cell system for cooling the elements;   wherein the circulation of the water of the first water-storage device through the first water circulation loop and the circulation of the water of the at least one second water-storage device through the second water circulation loop are separately controlled.   
     
     
         43 . The fuel-cell system according to  claim 25 , wherein, for each supply of the first-oxygen containing substance to the oxidation unit, a corresponding amount of water is injected by the water-injection device into the oxidation device. 
     
     
         44 . A method for generating electrical energy using a fuel-cell system, comprising:
 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   for the oxidizing, during the oxidizing:   supplying a first oxygen containing substance; and   injecting water.   
     
     
         45 . The method according to  claim 44 , wherein the fuel-cell system includes a drive system of a motor vehicle. 
     
     
         46 . The method according to  claim 44 , wherein the water is injected as one of a vapor and an aerosol. 
     
     
         47 . The method according to  claim 44 , further comprising 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. 
     
     
         48 . The method according to  claim 44 , further comprising:
 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.   
     
     
         49 . The method according to  claim 44 , further comprising:
 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.   
     
     
         50 . The method according to  claim 44 , further comprising:
 burning the raw material; and   supplying heat energy generated by the raw material burning to the reforming process.   
     
     
         51 . The method according to  claim 44 , wherein the raw material includes a hydrogen-containing substance. 
     
     
         52 . The method according to  claim 51 , wherein the hydrogen-containing substance includes at least one of methanol and gasoline. 
     
     
         53 . The method according to  claim 44 , further comprising:
 supplying compressed air at a first pressure to a cathode of the fuel-cell unit; and   supplying compressed air at a second pressure higher than the first pressure to a reformer unit that performs the reforming process.   
     
     
         54 . The method according to  claim 44 , further comprising:
 separating water from a cleaned-gas of a stream from an oxidation unit that performs the oxidizing step; and   supplying the separated water to a water-storage device that supplies the water that is injected during the oxidizing step.   
     
     
         55 . The method according to  claim 44 , further comprising separately controlling a first water circulation loop for providing the water that is injected during the oxidizing step from a first water-storage device and a second water circulation loop for circulating water from at least one second water-storage device for cooling elements of the fuel-cell system.