Abstract: The rate of platinum recrystallization of a platinum supported on carbon catalyst is reduced by depositing porous carbon on and around the supported platinum crystallites. The reduced rate of platinum recrystallization results in higher platinum surface areas over a period of time and therefore improves the performance of the catalyst. The porous carbon can be deposited by any suitable technique, a preferred method being to heat the supported platinum in the presence of carbon monoxide to decompose the carbon monoxide thereby depositing carbon on and around the platinum crystallites.

Abstract: The rate of platinum recrystallization of a platinum supported on carbon catalyst is reduced and the activity of the catalyst is increased by depositing porous carbon on and around the supported platinum crystallites and then heating the catalyst in an inert atmosphere or vacuum at a high temperature.

Abstract: In a stack of electrochemical cells, such as fuel cells, distinct channels behind each electrode for carrying reactant gas are eliminated by using highly porous gas distribution layers, such as porous electrode substrate material. This gas distribution layer must be sufficiently thick and have enough pores sufficiently large to permit a substantially free flow of reactant gas therethrough both perpendicular to and parallel to the catalyst layer.

Abstract: In a fuel cell power plant the anode and cathode exhausts are combined and burned in a burner with a first portion of the burner exhaust being delivered into fuel conditioning apparatus to provide the heat for converting a carbonaceous fuel to hydrogen. The hydrogen is then fed to the anode side of the fuel cells. A second portion of the burner exhaust is preferably used to drive a turbocharger for compressing the fuel cell oxidant which is usually air. If the fuel cells do not operate on pressurized reactants, then the energy in the second portion of the burner exhaust can be used for any other suitable purpose.

Abstract: In an electrochemical cell, such as a fuel cell, the gas distribution layer, which is the layer of material disposed directly behind and contiguous with the catalyst layer, is made from gas porous open cell carbon foam. Vitreous carbon foam is preferred. Vitreous carbon foam is extremely corrision resistant to many of the very reactive chemicals which might be used as an electrolyte in a fuel cell, such as phosphoric acid. It also has low electrical resistivity, good thermal conductivity, and can be made very thin and inexpensively. Preferably the cell catalyst layer is applied directly to one surface of the foam layer.

Abstract: A ribbed electrode substrate for an electrochemical cell comprises a gas porous substrate having ribs of hydrophilic material extending across one side thereof. The other side of the substrate is substantially flat and may have a catalyst layer disposed thereon. In one embodiment a stack of fuel cells uses electrodes having these ribbed substrates. A flat, gas impermeable plate separates the electrode substrates of adjacent cells, the ribs of each substrate abutting opposite surfaces of the plate forming channels for carrying reactant gas across the cells. Electrolyte is stored in the ribs, which are hydrophilic. The electrolyte in the ribs moves to and from the electrolyte matrix of the cell by capillary action through the substrate.

Abstract: A method for fabricating porous carbon sheet material and in particular for fabricating porous carbon fuel cell electrode substrates comprises coating carbon fibers with a mixture of furfuryl alcohol and a catalyst which polymerizes furfuryl alcohol, forming the fibers into a mat or sheet of the desired size and thickness, heating the mat to polymerize the furfuryl alcohol and to cure the resin so formed, and further heating the mat to carbonize the resin.Phosphoric acid is the preferred polymerization catalyst when the sheet material is to be used as a fuel cell electrode substrate. The method produces electrode substrates which are highly porous yet strong and which are also corrosion resistant, thermally conductive and electrically conductive.

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 for steam reforming a hydrocarbon feedstock to produce hydrogen, includes a plurality of reactor tubes disposed within a furnace. A portion of each reactor extends into the burner cavity or combustion volume of the furnace. Baffles, such as sleeves, are disposed around these portions of the reactor tubes to shield the tubes from excessive radiant heat from the wall of the burner cavity and to more evenly distribute heat among and around all of the reactors. These baffles permit the reactor tubes to be closely packed within the furnace and reduce temperature differences between the tubes.

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.

Abstract: In a fuel cell power plant comprising a plurality of stacks of molten carbonate fuel cells the CO.sub.2 produced at the anodes of the cells is combined with the process air for the cathode side of the stacks. The CO.sub.2 rich mixture is fed from stack to stack in series through the cathode sides thereof with heat being removed from the cathode side exhaust streams between consecutive stacks. This process improves cell performance by increasing the CO.sub.2 partial pressure within the stacks. The process also makes it possible to reduce the required heat exchanger heat transfer area needed to cool the cell exhaust products.

Abstract: A tubular catalytic reactor, such as for steam reforming a hydrocarbon feedstock to produce hydrogen, is disposed within a furnace and includes an annular first bed of reaction catalyst. A second bed of reaction catalyst is disposed coaxial with the first bed and inwardly thereof. Product gases from the first bed, without adding heat thereto, are passed through the second bed essentially adiabatically resulting in a substantial reduction in the amount of unreacted hydrocarbons heavier than methane which were present in the product gases leaving the first bed. The apparatus is compact and uses only the sensible heat in the reaction products leaving the first bed to reduce the level of unwanted hydrocarbons. Thus, in the process of the present invention, the reduction in the level of unwanted heavier hydrocarbons is accomplished in compact apparatus without burning additional fuel and without extracting additional heat energy from the furnace.

Abstract: An electrolyte reservoir layer disposed behind and adjacent one of the catalyst layers of a fuel cell is porous and hydrophilic to the electrolyte. In one embodiment the reservoir layer includes impregnations of hydrophobic material on the catalyst facing surface thereof and holes leading from the other surface to the impregnations for providing reactant gas passages through the reservoir layer to the catalyst layer. The impregnations of hydrophobic material are designed to provide good distribution of the reactant gas into the catalyst layer without consuming a large volume of the reservoir. In a preferred embodiment the reservoir is also the electrode substrate whereby the catalyst layer is bonded to the surface thereof.

Abstract: A support material for platinum, platinum alloys, or other noble metal catalyst, is made from carbon particles by heat treating the carbon until it is at least partially graphitized, depositing a metal on the heat treated carbon particles which will catalyze the oxidation of graphite in an oxidizing atmosphere, and oxidizing the surfaces of the heat treated carbon particles at the sites of the catalyst crystals to pit or etch the surfaces at these sites. When this material is used as a support for platinum it reduces the rate of platinum migration when the supported platinum catalyst is heated in the presence of a liquid, thereby reducing the loss of platinum surface area which often occurs under these conditions.

Abstract: The output from a selective oxidizer is controlled by modifying the rate of oxidant input in accordance with the operating temperature of the selective oxidizer. In a preferred embodiment, wherein the selective oxidizer has a slow temperature response, gross adjustments to the oxidant feed flow rate are made as a function of the fuel feed flow rate into the selective oxidizer, in addition to the fine adjustments made as a function of temperature.

Abstract: A method of fabricating a fuel cell electrode comprising an electrocatalyst and binder wherein the colloidal chemistry of the aqueous catalyst and the binder suspension are controlled during the deposition of the catalyst/binder onto an electrode substrate. Control is by addition of acids, bases, or salts to an aqueous suspension of binder and catalyst to adjust the pH to within certain ranges to form a flocculate. The flocculate is then fabricated into an electrode. The catalyst/binder distribution within the electrode and electrochemical performance, including decay characteristics, of the electrode are improved.

Abstract: A power plant for the generation of electricity utilizes high temperature fuel cells, such as molten carbonate fuel cells, as its main power supply. Part of the oxidant exhaust stream from the fuel cell is recycled through the fuel cell. Waste energy from the fuel cell in the form of exhaust gases, such as part of the oxidant exhaust, drives a turbocharger for compressing the oxidant used in the fuel cell. In a preferred embodiment the oxidant exhaust also is the source of energy for powering a bottoming cycle, such as a steam driven turbogenerator. Power plant efficiency is improved by making maximum use of the energy and heat generated within the system.

Abstract: An electrolyte reservoir layer disposed behind and adjacent one of the catalyst layers of a fuel cell is porous and hydrophilic to the electrolyte. In one embodiment the reservoir layer includes impregnations of hydrophobic material to provide reactant gas passages through the reservoir layer to the catalyst layer. Additionally the reservoir layer includes impregnations of a material similar to the fuel cell electrolyte retaining matrix material to improve electrolyte transfer from the matrix into the reservoir. The impregnations of hydrophobic material are designed to provide good distribution of the reactant gas into the catalyst layer without consuming a large volume of the reservoir. In a preferred embodiment the reservoir is also the electrode substrate whereby the catalyst layer is bonded to the surface thereof.

Abstract: An electrolyte reservoir layer disposed behind and adjacent one of the catalyst layers of a fuel cell is a porous, hydrophilic material. Excess liquid volume wicks into the reservoir layer through the catalyst layer and fills the smaller pores within the reservoir. The larger pores remain empty and provide clear passageways for the reactant gas to reach the catalyst. Wetproofing of the reservoir layer is not required. In a preferred embodiment the reservoir layer is the electrode substrate whereby the catalyst layer is bonded to the surface thereof.

Abstract: A support material for platinum, platinum alloys, or other noble metal catalyst, is made from carbon particles by heat treating the carbon until it is at least partially graphitized, depositing a metal on the heat treated carbon particles which will catalyze the oxidation of graphite in an oxidizing atmopshere, and oxidizing the surfaces of the heat treated carbon particles at the sites of the catalyst crysals to pit or etch the surfaces at these sites. When this material is used as a support for platinum it reduces the rate of platinum migration when the supported platinum catalyst is heated in the presence of a liquid, thereby reducing the loss of platinum surface area which often occurs under these conditions.