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 are provided for reducing the concentration of carbon monoxide in a gaseous reactant stream comprising carbon monoxide and water vapor. The catalyst bed of a water gas shift reactor is preferably divided into two sections. Alternatively, an assembly which includes two sequential reactors can be employed. The first section or reactor operates in an adiabatic fashion whereas the second section or reactor is cooled, thereby facilitating the further conversion of carbon monoxide in the second section or reactor. The gaseous reactant stream exiting the second section or reactor typically has a carbon monoxide concentration in the range from about 0.06% to about 0.14% by volume.

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 fuel cell power plant in which the fuel cell stack is enclosed within a containment vessel and in which reformer burner exhaust is used to pressurize and purge the containment vessel is disclosed. The fuel cell power plant provides dynamic pressure balancing between the purge gas and fuel cell reactants to prevent leakage of the reactants from the fuel cell yet avoid an excessive pressure differential between the fuel cell and the containment vessel.

Abstract: The fuel cell stack is made from two basic finished component subassemblies which are stacked repetitively atop each other in alternating fashion. One of the components is an electrode subassembly, and the other is a separator plate-flow field subassembly. The subassemblies are formed from several different material layers which are sintered and shrunk to operating size and density prior to the stack being assembled. The finished subassemblies are layered atop each other to form the stack and then heated to an elevated subsintering temperature and subjected to a light compressive load so that abutting surfaces of the adjacent subassemlies are creep flattened into intimate adherent contact with each other thereby forming a monolithic stack assembly.

Abstract: The fuel cell power plant operates at higher reactant pressures, and thus higher power density (lower cost) and efficiency, by providing reactant reformer steam from a separate steam boiler. Instead of supplying coolant steam to the reformer, the coolant is operated in a closed loop apart from the reformer, and the coolant steam is used to drive a steam generator to produce additional electricity. A portion of the raw fuel is burned within the steam boiler and the remainder is passed through the reformer and thence to the fuel cells. Boiler exhaust is used to drive a turocompressor which pressurizes the air used on the cathode side of the fuel cells.

Abstract: The fuel cell power plant operates at higher reactant pressures, and thus higher power density (lower cost) and efficiency, by providing reactant reformer steam from a separate steam boiler. Instead of supplying coolant steam to the reformer, the coolant is operated in a closed loop apart from the reformer, and the coolant steam is used to drive a steam generator to produce additional electricity. A portion of the raw fuel is burned within the steam boiler and the remainder is passed through the reformer and thence to the fuel cells. Boiler exhaust is used to drive a turocompressor which pressurizes the air used on the cathode side of the fuel cells.

Abstract: A reformer apparatus 8 has a heat shield 17 for a reformer duct 16. Various construction details which increase the durability of the heat shield are developed. In one embodiment, the heat shield includes a plurality of rings 82 which are axially and circumferentially segmented, the rings being supported by a platform on which the stack of rings rests. At least one of the rings has a pair of segments each of which has a V-shaped identation in the end which receives a V-shaped projection of the adjacent segment leaving a circumferential gap between the segments which does not extend radially between the segments of the ring.

Abstract: A catalytic reaction apparatus, such as for steam reforming a hydrocarbon feedstock to produce hydrogen, includes a tubular reactor disposed within a furnace. The reactor includes an annular reaction chamber which is heated along its outer wall by a countercurrent flow of furnace gases traveling through a narrow annulus external thereof. The reaction chamber is also heated along its inner wall by regenerative heat from the reaction products which leave the annular chamber and flow countercurrent to the flow within the reaction chamber through a narrow annulus disposed along the inner wall thereof. This apparatus is capable of high reactor thermal efficiency over a wide range of heating rates, including very high heating rates. The apparatus is very compact and is particularly suited for use with a large number of closely packed tubular reactors disposed within a single furnace.

Abstract: Compact reaction apparatus, such as apparatus for steam reforming a hydrocarbon feedstock to produce hydrogen, comprises a plurality of tubular reactors vertically disposed and closely packed within a furnace. The furnace is divided into an enhanced heat transfer portion and a burner cavity. Each of the several reactors is disposed partly within the burner cavity and partly within the enhanced heat transfer portion. Heat transfer means, such as particles of a heat transfer packing material, is disposed within the enhanced heat transfer portion of the furnace and is constructed and arranged to provide substantially uniform and enhanced conductive, convective, and radiant heating of that portion of the reactors disposed within the heat transfer portion.