Abstract: A fuel cell electric power generation system includes an electric power generation subsystem, a fuel processing subsystem including a furnace, an oxidant subsystem, a water circulation subsystem, and a temperature control subsystem. Interactions between the subsystems are simplified and component integration improves thermal and electrical efficiency of the system. In one embodiment, a reformer, a fuel stream humidifier and a heat exchanger are disposed within the furnace, with the humidifier outlet fluidly connected to the reformer inlet and the heat exchanger outlet fluidly connected to a desulfurizer located outside of the furnace. The fuel processing subsystem can also include a shift reactor that exchanges heat with a cathode exhaust stream directed to the shift reactor from the power generation subsystem. After passing through the shift reactor, the cathode exhaust stream is preferably directed to the furnace burner.

Abstract: Improved fuel processing systems convert a hydrocarbon fuel into a reformate stream comprising hydrogen. Improved steam reformers and fuel processing systems employ steam reforming catalyst compositions that are oxygen-tolerant and/or sulfur-tolerant. Improved fuel processing systems employ shift reactors comprise shift catalyst compositions that are oxygen-tolerant and self-reducing. Improved fuel processing systems also comprise a preoxidizer or first-stage selective oxidizer, shift reactor, and selective oxidizer connected in series. An improved integrated reactor comprises a metal oxide bed and shift catalyst bed, and fuel processing systems comprising the improved integrated reactor.

Abstract: A fuel cell electric power generation system comprises an electric power generation subsystem, a fuel processing subsystem, an oxidant subsystem, a water circulation subsystem, and a temperature control subsystem. The improved system employs a novel arrangement of components that provides improved interaction between the subsystems while also simplifying the apparatus by integrating components to provide improved thermal and electrical efficiency. The fuel processing subsystem preferably comprises a furnace for providing heat to a plurality of components disposed within the furnace. In one embodiment, a reformer, a fuel stream humidifier, and a heat exchanger are all disposed within the furnace vessel, with the outlet of the humidifier fluidly connected to the inlet of the reformer and the outlet of the heat exchanger fluidly connected to a desulfurizer located external to the furnace.

Abstract: A fuel cell electric power generation system comprises an electric power generation subsystem, a fuel processing subsystem, an oxidant subsystem, a water circulation subsystem, and a temperature control subsystem. The improved system employs a novel arrangement of components which provides improved interaction between the subsystems while also simplifying the apparatus by integrating components to provide improved thermal and electrical efficiency. The fuel processing subsystem preferably comprises a furnace for providing heat to a plurality of components disposed within the furnace. In one embodiment, a reformer, a fuel stream humidifier, and a heat exchanger are all disposed within the furnace vessel, with the outlet of the humidifier fluidly connected to the inlet of the reformer and the outlet of the heat exchanger fluidly connected to a desulfurizer located external to the furnace.

Abstract: An apparatus for the two-stage selective oxidation of carbon monoxide to carbon dioxide in a fuel stream comprising hydrogen and carbon monoxide. The apparatus includes primary and secondary reaction chambers, which deliver a hydrogen-rich outlet gas stream having a carbon monoxide concentration of less than about 5 ppm. When an increase in the carbon monoxide concentration in the outlet stream of the primary reaction chamber is detected, then the flow through the primary reaction chamber is reversed. The selective oxidizer employs a temperature-based control strategy as an oxygen-containing gas stream flow rate adjustment around the flow rate initially set in direct proportion to the fuel gas stream flow rate. The control strategy regulates the amount of oxygen-containing gas mixed with the gaseous fuel stream as a function of the difference between the temperature at a location at or near the end of the primary reaction chamber and the temperature at the outlet of the primary reaction chamber.

Abstract: An apparatus and method are provided for the two-stage selective oxidation of carbon monoxide to carbon dioxide in a fuel stream comprising hydrogen and carbon monoxide. The apparatus includes primary and secondary reaction chambers, which deliver a hydrogen-rich outlet gas stream having a carbon monoxide concentration of less than about 5 ppm. When an increase in the carbon monoxide concentration in the outlet stream of the primary reaction chamber is detected, then the flow through the primary reaction chamber is reversed. The selective oxidizer employs a temperature-based control strategy as an oxygen-containing gas stream flow rate adjustment around the flow rate initially set in direct proportion to the fuel gas stream flow rate.

Abstract: A catalytic hydrocarbon reformer operates at lower temperature and pressure relative to conventional reformers. Convective heat transfer between the hot combustion gas stream and the reactor tube is enhanced through use of a narrow gap heat transfer area, which induces turbulent flow of the combustion gas stream across the reactor tube. The reactor tube includes a catalyst fines collection tube to accumulate and retain catalyst particles or fines entrained in the reformate gas stream.

Abstract: A method and apparatus for selectively oxidizing the carbon monoxide present in a mixture of gases, including hydrogen, to carbon dioxide is disclosed. Oxygen or an oxygen-containing gas mixture is introduced at locations along the latter portion of the reaction chamber in an isothermal reactor to selectively oxidize the carbon monoxide to carbon dioxide and to suppress the reverse to water-shift reaction, which produces carbon monoxide and water from carbon dioxide and hydrogen.

Abstract: A method and apparatus is provided for removing water accumulated at the cathode of an electrochemical fuel cell incorporating a solid polymer ion exchange membrane. Liquid water accumulated at the cathode can be removed by maintaining a partial pressure of water vapor in the hydrogen-containing gas supply below the saturation pressure of water vapor therein such that water accumulated at the cathode is drawn by a concentration gradient toward the anode across the membrane and is absorbed as water vapor into the hydrogen-containing gas supply between the inlet and the outlet. In one embodiment, the partial pressure of water vapor in the hydrogen-containing gas supply is maintained below the saturation pressure of water vapor therein by imparting a pressure drop between the inlet and the outlet sufficient to draw water accumulated at the cathode toward the anode.

Abstract: A solid polymer fuel cell electric power generation system removes a substantial portion of water accumulated at the cathode in the outlet fuel stream of the anode. The system permits the operation of a hydrogen/oxygen fuel cell in a dead-ended mode where substantially pure oxygen is employed as the oxidant supply or using low oxygen stoichiometry where a dilute oxidant source, such as oxygen-containing air, is employed as the oxidant supply. The system thereby eliminates the need for an oxygen recirculation pump in systems operating on substantially pure oxygen, and substantially reduces the parasitic load to pressurize the oxidant stream in systems operating on dilute oxidant streams.

Abstract: A power plant system produces utility grade electrical AC power from gaseous or liquid hydrocarbon fuels using a fuel cell stack employing ion exchange membranes. The fuel is desulfurized, mixed with water, heated and vaporized before being introduced into a reformer. The reformer produces a hydrogen-rich gas which is then directed through a series of heat exchangers, shift converters and a selective oxidizer. The processed fuel stream is combined in the fuel cell stack with a pressurized oxidant stream to generate DC power. Oxidant pressure is supplied by compressors driven by turbines using heated system exhaust gases. The DC power is converted into utility grade AC power using an inverter augmented by a battery peaking unit for rapid load following. The water generated in the fuel cell stack is recycled and used to cool the fuel cell stack and to humidify the fuel stream and oxidant stream prior to their introduction to the fuel cell stack.

Abstract: A method and apparatus for selectively oxidizing the carbon monoxide present in a mixture of gases, including hydrogen, to carbon dioxide is disclosed. Oxygen or an oxygen-containing gas mixture is introduced at locations along the latter portion of the reaction chamber in an isothermal reactor to selectively oxidize the carbon monoxide to carbon dioxide and to suppress the reverse water-shift reaction, which produces carbon monoxide and water from carbon dioxide and hydrogen.

Abstract: A membrane electrode and seal assembly for an electrochemical fuel cell comprises first and second layers of porous electrically conductive sheet material, such as carbon fiber paper. The sheet material layers have a solid polymer ion exchange membrane interposed therebetween. The sheet material layers cover and support the membrane over substantially its entire surface area. The sheet material layers are coated with a catalyst to render them electrochemically active, and are bonded together with the membrane to form a consolidated assembly. Openings are formed in the layers of sheet material and the membrane to accommodate the passage of fluids through the assembly. Channels formed in the layers of sheet material generally circumscribe the openings and the electrochemically active region of the sheet material. Solid preformed gaskets are disposed in the channels. The gasketing technique can also be applied to the membrane and seal assemblies of the humidification portion of fuel cell stacks.

Abstract: A method and apparatus is provided for removing water accumulated at the cathode of an electrochemical fuel cell incorporating a solid polymer ion exchange membrane. Liquid water accumulated at the cathode can be removed by maintaining a partial pressure of water vapor in the hydrogen-containing gas supply below the saturation pressure of water vapor therein such that water accumulated at the cathode is drawn by a concentration gradient toward the anode across the membrane and is absorbed as water vapor into the hydrogen-containing gas supply between the inlet and the outlet. In one embodiment, the partial pressure of water vapor in the hydrogen-containing gas supply is maintained below the saturation pressure of water vapor therein by imparting a pressure drop between the inlet and the outlet sufficient to draw water accumulated at the cathode toward the anode.

Abstract: A compact modular isothermal reactor for converting a feedstock such as methanol into a fuel usable in power generation systems, such as electrochemical fuel cells, is provided. The reactor includes a sealing plate, a baffle plate having heat transfer surfaces extending toward the sealing plate, and a housing having an interior substantially circumscribing the heat transfer surfaces The cooperating surfaces of the sealing plate, baffle plate, heat transfer surfaces and housing interior define a labyrinthine channel for containing a suitable quantity of solid catalyst and through which feedstock flows. The cooperating surfaces of a fluid flow plate and the baffle plate define a flow passage for carrying a thermal fluid. Heat is transferred from the thermal fluid to the feedstock by the heat transfer surfaces. In two alternative designs, thermally conductive pins extending from the baffle plate or a pair of spaced folded thermally conductive plates transfer heat to the interior of a catalyst containment vessel.

Abstract: An integrated fuel cell power generation system comprises a fuel cell stack having a humidification section and an electrochemically active section. The humidification section imparts water vapor to an inlet hydrogen containing fuel stream and an inlet oxygen containing oxidant stream. The electrochemically active section comprises fuel cells for promoting the electrocatalytic conversion of the humidified fuel and oxidant streams to electric current and product water. The electrochemically active section also includes a coolant water stream for absorbing heat generated in the active section. The system includes a heat exchanger for removing heat from the coolant water stream exiting the active section, a water separator for removing water from the oxidant stream exiting the fuel cell stack, and a coolant reservoir for receiving the removed water stream from the water separator and from the heat exchanger. The coolant water stream is drawn from the coolant reservoir.

Abstract: Novel fluid flow field plates for use in a solid polymer electrolyte fuel cell include in a major surface thereof, multiple continuous open-faced fluid flow channels each of which traverses the central area of the plate surface in a serpentine manner. Each of the channels has a fluid inlet at one end and a fluid outlet at the other end which are directly connected to common fluid supply and exhaust openings, respectively, defined in the plate.

Abstract: The invention disclosed is a novel fluid flow field plate for use in a solid polymer electrolyte fuel cell. The plate includes in a major surface thereof, a continuous open-faced fluid flow channel which traverses the central area of the plate surface in a serpentine manner. The channel has a fluid inlet at one end for receiving a reactant gas and a fluid exhaust at the other end for removing excess reactant gas and reaction products from the cell.