A fuel cell system includes a solid oxide fuel cell capable of generating power by receiving a supply of a reformed gas and an oxidant gas; an oxidant gas supply device that supplies the oxidant gas to the fuel cell; a reforming unit that supplies the reformed gas to the fuel cell; a fuel supply device that supplies a fuel which is a raw material for the reformed gas to the reforming unit; a combustion unit that combusts discharged gases of the fuel cell, wherein the reforming unit can reform the fuel into the reformed gas by exchanging heat with a combustion gas produced by the combustion unit; and a first control unit controls the fuel supply device to additionally supply the fuel to the fuel cell through the reforming unit in order to prevent the oxidant gas from flowing in from downstream of a fuel electrode of the fuel cell at the time of stopping the system. The fuel cell system further includes a second control unit that controls to supply the fuel to the reforming unit before the additional supply so that the temperature of the reformed gas flowing into the fuel cell does not exceed a predetermined temperature at the time of stopping the system.

A high efficiency hydrogen fuel system for an aircraft at high altitude which utilizes compressors to compress air to a sufficiently high pressure for the fuel cell. Liquid hydrogen is compressed and then utilized in heat exchangers to cool the compressed air, maintaining the air at a temperature low enough for the fuel cell. The hydrogen is also used to cool the fuel cell as it is also depressurized prior to its entry in the fuel cell cycle. A water condensation system allows for water removal from the airstream to reduce impacts to the atmosphere. The hydrogen fuel system may be used with VTOL aircraft, which may allow them to fly at higher elevations. The hydrogen fuel system may be used with other subsonic and supersonic aircraft, such as with asymmetric wing aircraft.

A system and method are provided for increasing efficiency of a solid oxide fuel cell (SOFC) system by recapturing water via a condensate extraction system that extracts water from a hot cathode exhaust flow of the SOFC stack. Further, the SOFC system can include a radiant heater which has a fuel inlet, an air intake, and an exhaust outlet independent and separate from the power generating components in the SOFC system. The radiant heater can bring the SOFC stack up to operating temperature quickly and/or maintain near operational mode temperatures of the SOFC stack during a hibernation mode.

A method for ammonia decomposition is disclosed. The method may comprise providing a catalyst comprising an zirconia support and a layer adjacent to the support. The layer comprises a tetragonal phase comprising zirconium, cerium, and oxygen, an oxide of at least one of an alkali metal and a rare earth metal, and an active metal. The method may comprise bringing the catalyst in contact with ammonia at a temperature of from about 400° C. to 700° C. to generate a reformate stream comprising hydrogen and nitrogen at an ammonia conversion efficiency of at least about 70%. The method may comprise directing the hydrogen to generate electricity. The method may comprise generating heat for a reformer comprising the catalyst by combustion of gases or by electricity generated from hydrogen.

A non-catalytic microcombustion based FFC for the direct use of hydrocarbons for power generation. The potential for high FFC performance (450 mW.Math.cm.sup.−2 power density and 50% fuel utilization) in propane/air microcombustion exhaust was demonstrated. The micro flow reactor was used as a fuel reformer for equivalence ratios from 1-5.5. Soot formation in the micro flow reactor was not observed at equivalence ratios from 1 to 5.5 and maximum wall temperatures ranging from 750 to 900° C. H.sub.2 and CO concentrations in the exhaust were found to have a strong temperature dependence that varies with the maximum wall temperature and the local flame temperature.

A fuel cell system comprising at least one fuel cell arranged for a reformation of a hydrocarbon and a hydrocarbon generation unit connected to an anode outlet of the fuel cell for generating the hydrocarbon from carbon monoxide and hydrogen included in a partially unconverted exhaust stream of the anode outlet of the fuel cell, where the fuel cell is thermally decoupled from the hydrocarbon generation unit so that the exothermal hydrocarbon generation reaction and the endothermal reformation reaction proceed without one reaction thermally interfering the other.

An air supply system, comprising at least two air blowers and at least two communication valves; wherein one air blower is connected to a main air passage through the corresponding communication valve; and at least one other is connected to a reformer air passage and a stack air passage through at least one other communication valve, respectively. At least two air blowers are provided to connect the at least two communication valves.

A fuel cell system that raises temperature of fuel cells by supplying heated air to the fuel cells during starting up period. The fuel cell system includes a plurality of fuel cells, a fuel supply path connected parallelly to the fuel cells to provide fuel thereto, an air supply path connected serially to the fuel cells to provide air thereto, a heat exchanger arranged in the fuel supply path to heat air or fuel, an air heat exchanger arranged in the air supply path to heat air; and a connection path connecting a position of the air supply path upstream to the air heat exchanger with a position of the fuel supply path upstream to the heat exchanger. A first control valve is arranged in the air supply path for controlling the air flowing into to the air heat exchanger. A second control valve arranged in the connection path for controlling the air flowing into the heat exchanger. The fuel cell system controls opening degrees of the first and second control valves during the start-up period of the fuel cell system to supply heated air to the fuel cells through both the air supply path and the fuel supply path.

-- A coating composition enables film formation at low cost with a simple method by using a zirconium alkoxide and an yttrium compound as starting raw materials, and enables a dense yttria-stabilized zirconia layer to be obtained, The coating composition containing the zirconium alkoxide, the yttrium compound, a chelate compound, a catalyst, water, and an organic solvent is obtained. The coating composition may also contain yttria-stabilized zirconia fine particles

A fuel cell system includes at least one spark igniter containing an insulated cable where at least a first end of the insulated cable is positioned within a reaction zone of the fuel cell system. A power supply is configured to provide a direct current (DC) voltage to the at least one spark igniter such that a spark is generated at the first end of the insulated cable.