摘要:
A homogeneous ceria-based mixed-metal oxide, useful as a catalyst support, a co-catalyst and/or a getter has a relatively large surface area per weight, typically exceeding 150 m2/g, a structure of nanocrystallites having diameters of less than 4 nm, and including pores larger than the nanocrystallites and having diameters in the range of 4 to about 9 nm. The ratio of pore volumes, VP, to skeletal structure volumes, VS, is typically less than about 2.5, and the surface area per unit volume of the oxide material is greater than 320 m2/cm3, for low internal mass transfer resistance and large effective surface area for reaction activity. The mixed metal oxide is ceria-based, includes Zr and or Hf, and is made by a novel co-precipitation process. A highly dispersed catalyst metal, typically a noble metal such as Pt, may be loaded on to the mixed metal oxide support from a catalyst metal-containing solution following a selected acid surface treatment of the oxide support. Appropriate ratioing of the Ce and other metal constituents of the oxide support contribute to it retaining in a cubic phase and enhancing catalytic performance. Rhenium is preferably further loaded on to the mixed-metal oxide support and passivated, to increase the activity of the catalyst. The metal-loaded mixed-metal oxide catalyst is applied particularly in water gas shift reactions as associated with fuel processing systems, as for fuel cells.
摘要:
A homogeneous ceria-based mixed-metal oxide, useful as a catalyst support, a co-catalyst and/or a getter has a relatively large surface area per weight, typically exceeding 150 m2/g, a structure of nanocrystallites having diameters of less than 4 nm, and including pores larger than the nanocrystallites and having diameters in the range of 4 to about 9 nm. The ratio of pore volumes, VP, to skeletal structure volumes, VS, is typically less than about 2.5, and the surface area per unit volume of the oxide material is greater than 320 m2/cm3, for low internal mass transfer resistance and large effective surface area for reaction activity. The mixed metal oxide is ceria-based, includes Zr and or Hf, and is made by a novel co-precipitation process. A highly dispersed catalyst metal, typically a noble metal such as Pt, may be loaded on to the mixed metal oxide support from a catalyst metal-containing solution following a selected acid surface treatment of the oxide support. Appropriate ratioing of the Ce and other metal constituents of the oxide support contribute to it retaining in a cubic phase and enhancing catalytic performance. Rhenium is preferably further loaded on to the mixed-metal oxide support and passivated, to increase the activity of the catalyst. The metal-loaded mixed-metal oxide catalyst is applied particularly in water gas shift reactions as associated with fuel processing systems, as for fuel cells.
摘要翻译:可用作催化剂载体,助催化剂和/或吸气剂的均匀的二氧化铈基混合金属氧化物具有相对较大的每重量的表面积,通常超过150m 2 / g, 具有直径小于4nm的纳米晶体的结构,并且包括大于纳米微晶并且直径在4至约9nm范围内的孔。 孔体积V V P与骨架结构体积V S S的比例通常小于约2.5,并且氧化物材料的每单位体积的表面积为 大于320m 2 / cm 3,因为低的内部传质阻力和反应活性的大的有效表面积。 复合金属氧化物是二氧化铈基,包括Zr和Hf,并且通过新的共沉淀法制备。 通过选择的氧化物载体的酸表面处理,可以将高度分散的催化剂金属(通常为贵金属如Pt)负载到来自含催化剂金属的溶液的混合金属氧化物载体上。 Ce和其他金属成分对氧化物载体的适当比例有助于其保持立方相并提高催化性能。 优选将铼进一步负载在混合金属氧化物载体上并钝化,以提高催化剂的活性。 负载金属的混合金属氧化物催化剂特别适用于燃料处理系统与燃料电池相关的水煤气变换反应。
摘要:
The materials of adjoining porous metal substrate (12), oxide (14), and Pd-alloy membrane (16) layers of a composite, H2—separation palladium membrane (10) have respective thermal expansion coefficients (TEC) which differ from one another so little as to resist failure by TEC mismatch from thermal cycling. TEC differences (20, 22) of less than 3 μm/(m.k) between materials of adjacent layers are achieved by a composite system of a 446 stainless steel substrate, an oxide layer of 4 wt % yittria-zirconia, and a 77 wt % Pd-23 wt % Ag or 60 wt % Pd-40 wt % Cu, membrane, having TECs of 11, 11, and 13.9 μm/(m.k), respectively. The Intermediate oxide layer comprises particles forming pores having an average pore sizeless than 5 microns, and preferably less than about 3 microns, in thickness.
摘要:
The fuel processing system of the present invention supplies a flow of H2-rich reformate to a water gas shift membrane reactor, comprising a water gas shift reaction region and a permeate region, separated by an H2-separation membrane H2 formed over a catalyst in the reaction region selectively passes through the H2-separation membrane to the permeate region for delivery to a use point (such as the fuel cell of a fuel cell power plant) A sweep gas, preferably steam, removes the H2 from the permeate region The direction of sweep gas flow relative to the reformate flow is controlled for H2-separation performance and is used to determine the loading of the catalyst in the reaction region Coolant, thermal and/or pressure control subsystems of the fuel cell power plant may be integrated with the fuel processing system
摘要:
A power system for an aircraft includes a solid oxide fuel cell system which generates electric power for the aircraft and an exhaust stream; and a heat exchanger for transferring heat from the exhaust stream of the solid oxide fuel cell to a heat requiring system or component of the aircraft. The heat can be transferred to fuel for the primary engine of the aircraft. Further, the same fuel can be used to power both the primary engine and the SOFC. A heat exchanger is positioned to cool reformate before feeding to the fuel cell. SOFC exhaust is treated and used as inerting gas. Finally, oxidant to the SOFC can be obtained from the aircraft cabin, or exterior, or both.
摘要:
A fuel processing system (FPS) (110) is provided for a fuel cell power plant (115) having a fuel cell stack assembly (CSA) (56). A water gas shift (WGS) reaction section (12, 120) of the FPS (110) reduces the concentration of carbon monoxide (CO) in the supplied hydrocarbon reformate, and a preferred oxidation (PROX) section (40) further reduces the CO concentration to an acceptable level. The WGS section (12, 120) includes a reactor (124) with a high activity catalyst for reducing the reformate Co concentration to a relatively low level, e.g., 2,000 ppmv or less, thereby relatively reducing the structural volume of the FPS (110). The high activity catalyst is active at temperatures as low as 250° C., and may be a noble-metal-on-ceria catalyst of Pt and Re on a nanocrystaline, cerium oxide-based support. Then only a low temperature PROX reactor (46) is required for preferential oxidation in the FPS (110).
摘要:
A sulfur scrubbing method and structure is operable to remove substantially all of the sulfur present in an undiluted oxygenated hydrocarbon fuel stock supply which can be used to power an internal combustion engine or a fuel cell power plant in a mobile environment, such as an automobile, bus, truck, boat, or the like, or in a stationary environment. The fuel stock can be gasoline, diesel fuel, or other like fuels which contain relatively high levels of organic sulfur compounds such as mercaptans, sulfides, disulfides, thiophenes, and the like. The undiluted hydrocarbon fuel supply is passed through a desulfurizer bed which is provided with a high surface area nickel reactant, and wherein essentially all of the nickel reactant in the scrubber bed reacts with sulfur in the fuel stream, so as to remove sulfur from the fuel stream by converting it to nickel sulfide on the scrubber bed. The desulfurized organic remnants of the fuel stream continue through the remainder of the fuel processing system in the fuel cell power plant, or through the internal combustion engine. The desulfurizer bed is preferably formed from a high surface area ceramic foam monolith, the pores of which are coated with the high surface area nickel reactant. The use of the foam monolith combined with the high surface area of the reactant, enables essentially 100% of the nickel reactant to come into contact with the fuel stream being desulfurized. The scrubber bed can also be formed from high surface area nickel coated alumina pellets, from a high surface area nickel coated ceramic extrusion, from high surface area nickel pellets, and from high surface area nickel extrudates.
摘要:
An H2-permeable membrane system (117) comprises an electroless-deposited plating (115) of Pd or Pd alloy on a porous support (110, 110′). The Pd plating comprises face-centered cubic crystals cumulatively having a morphology of hexagonal platelets. The permeability to H2 of the membrane plating (115) on the porous support is significantly enhanced, being at least greater than about 1.3×10−8 mol·m−1·s−·Pa−0.5 at 350° C., and even greater than about 3.4×10−8 mol·m−1·s−1·Pa−0.5. The porous support (110, 110′) may be stainless steel (1100 and include a thin ceramic interlayer (110′) on which the Pd is plated. The method of providing the electroless-deposited plating includes preheating a Pd electroless plating solution to near a plating temperature substantially greater than room temperature, e.g. 60° C., prior to plating.
摘要:
A homogeneous ceria-based mixed-metal oxide, useful as a catalyst support, a co-catalyst and/or a getter has a relatively large surface area per weight, typically exceeding 150 m2/g, a structure of nanocrystallites having diameters of less than 4 nm, and including pores larger than the nanocrystallites and having diameters in the range of 4 to about 9 nm. The ratio of pore volumes, VP, to skeletal structure volumes, VS, is typically less than about 2.5, and the surface area per unit volume of the oxide material is greater than 320 m2/cm3, for low internal mass transfer resistance and large effective surface area for reaction activity. The mixed metal oxide is ceria-based, includes Zr and or Hf, and is made by a novel co-precipitation process. A highly dispersed catalyst metal, typically a noble metal such as Pt, may be loaded on to the mixed metal oxide support from a catalyst metal-containing solution following a selected acid surface treatment of the oxide support. Appropriate ratioing of the Ce and other metal constituents of the oxide support contribute to it retaining in a cubic phase and enhancing catalytic performance. Rhenium is preferably further loaded on to the mixed-metal oxide support and passivated, to increase the activity of the catalyst. The metal-loaded mixed-metal oxide catalyst is applied particularly in water gas shift reactions as associated with fuel processing systems, as for fuel cells.
摘要:
A sulfur scrubbing method and structure is operable to remove substantially all of the sulfur present in an undiluted oxygenated hydrocarbon fuel stock supply which can be used to power an internal combustion engine or a fuel cell power plant in a mobile environment, such as an automobile, bus, truck, boat, or the like, or in a stationary environment. The fuel stock can be gasoline, diesel fuel, or other like fuels which contain relatively high levels of organic sulfur compounds such as mercaptans, sulfides, disulfides, thiophenes, and the like. The undiluted hydrocarbon fuel supply is passed through a desulfurizer bed which is provided with a high surface area nickel reactant, and wherein essentially all of the nickel reactant in the scrubber bed reacts with sulfur in the fuel stream, so as to remove sulfur from the fuel stream by converting it to nickel sulfide on the scrubber bed. The desulfurized organic remnants of the fuel stream continue through the remainder of the fuel processing system in the fuel cell power plant, or through the internal combustion engine. The desulfurizer bed is preferably formed from a high surface area ceramic foam monolith, the pores of which are coated with the high surface area nickel reactant. The use of the foam monolith combined with the high surface area of the reactant, enables essentially 100% of the nickel reactant to come into contact with the fuel stream being desulfurized. The scrubber bed can also be formed from high surface area nickel coated alumina pellets, from a high surface area nickel coated ceramic extrusion, from high surface area nickel pellets, and from high surface area nickel extrudates.