摘要:
In a solid-oxide fuel cell system, the fuel cell stacks, the fuel reformer, tail gas combuster, heat exchangers, and fuel/air manifold, are contained in a “hot zone” within a thermal enclosure. A separate and larger structural enclosure surrounds the thermal enclosure, defining a “cool zone” outside the thermal enclosure for incorporation of “cool” components such as the air supply system and the electronic control system. To prevent unwanted temperature rise in the cool zone during shutdown, from residual heat escaping from the hot zone through the thermal enclosure, the structural enclosure is provided with vents through the lower and upper walls thereof to permit thermal convective circulation of air through the enclosure. The vents are baffled to prevent entry of splash and other contaminants, and the lower vent is provided with a float valve to prevent flooding of the enclosure in event of immersion of the SOFC system.
摘要:
A solid-oxide fuel cell system including an integrated reforming unit comprising a hydrocarbon fuel reformer; an integral tail gas and cathode air combustor and reformer heat exchanger; a fuel pre-heater and fuel injector cooler; a fuel injector and fuel/air mixer and vaporizer; a reforming air pre-heating heat exchanger; a reforming air temperature control valve and means; and a pre-reformer start-up combustor. The integration of a plate reformer, tail gas combustor, and combustor gas heat exchanger allows for efficient operation modes of the reformer, both endothermic and exothermic as desired. The combustor gas heat exchanger aids in temperature regulation of the reformer and reduces significant thermal gradients in the unit.
摘要:
A solid-oxide fuel cell system having “hot” components, e.g., the fuel cell stacks, the fuel reformer, tail gas combuster, heat exchangers, and fuel/air manifold, contained in a “hot zone” within a thermal enclosure intended specifically for minimizing heat transfer to its exterior and having no significant structural or protective function for its contents. A two-part clamshell arrangement allows all piping and leads which must pass through the enclosure to do so at the join line between the parts, thus eliminating need for ports and fittings in the thermal enclosure. A separate and larger structural enclosure surrounds the thermal enclosure, defining a “cool zone” outside the thermal enclosure for incorporation of “cool” components, e.g., the air supply system and the electronic control system, and providing structural protection for all components of the fuel cell system.
摘要:
In a fuel cell assembly, nickel-based anodes are readily oxidized when exposed to oxygen as may happen through atmospheric invasion of the assembly during cool-down following shutdown of the assembly. Repeated anode oxidation and reduction can be destructive of the anodes, leading to cracking and failure. To prevent such oxygen migration, check valves and oxygen getter devices containing oxygen-scavenging material such as metallic nickel are provided in the reformate passageways leading to and from the anodes. The check valves preferably are closed by gravity. Oxidation of the oxygen-gettering material is readily reversed through reduction by reformate when the assembly is restarted.
摘要:
In a fuel cell assembly, nickel-based anodes are readily oxidized when exposed to oxygen as may happen through atmospheric invasion of the assembly during cool-down following shutdown of the assembly. Repeated anode oxidation and reduction can be destructive of the anodes, leading to cracking and failure. To prevent such oxygen migration, oxygen getter devices containing oxygen-gettering material such as metallic nickel are provided in the fuel passageways leading to and from the anodes. Oxidation of the oxygen-gettering material is readily reversed through reduction by fuel when the assembly is restarted.
摘要:
A load frame with mechanical springs for providing compression to a fuel cell stack during assembly and operation of a fuel cell assembly. The stack assembly load frame includes a base plate for supporting the stack, a moveable spring holder above the stack, a retaining plate above the spring holder, and tubular supports or rods retaining the post-sintered spacing established by the applied load defining the spacing of the base plate from the retaining plate. A spring for maintaining compression in each stack is positioned between the spring holder and the retaining plate. The invention further comprises a method for assembling a fuel cell assembly to provide an adequate compressive load to the stack during assembly and operation.
摘要:
An improved system for more uniformly distributing gaseous fuel over the anode surface of a fuel cell, comprising an interconnect subassembly for electrically connecting anodes and cathodes of adjacent fuel cells in a fuel cell stack. The subassembly includes a perforated plate disposed adjacent the anode surface. The plate may be parallel to or inclined to the anode surface and forms a first wall of a fuel plenum for uniformly distributing fuel via the perforations over the entire surface of the anode. The second wall of the plenum is a plate separating the fuel flow from air flowing across the cathode. Electrical continuity across the interconnect subassembly may be provided, for example, by non-planar upsets such as bumps and dimples in the two plenum plate components, or by metallic foam or filaments disposed between the plates and the electrodes.
摘要:
A dual function composite oxygen transport membrane having a layered structure of mixed conducting oxygen transport materials on a first side of a porous substrate and a reforming catalyst layer on an opposing second side of the porous substrate. The layered structure of the mixed conducting oxygen transport materials contains an intermediate porous layer of mixed conducting oxygen transport materials formed on the porous substrate with a dense impervious layer of mixed conducting oxygen transport materials over the intermediate porous layer, and an optional surface exchange layer of mixed conducting oxygen transport materials over the dense impervious layer. The layered structure and the reforming catalyst layer are formed in separate steps.
摘要:
A method of operating an oxygen transport membrane based reforming system employing one or more packs of thermally coupled panels of reformer tubes and oxygen transport membrane (“OTM”) reactors close to thermo-neutral point is provided. The method produces syngas by converting a hydrocarbon-containing feed, such as natural gas in the reformer tubes of a pack by endothermic steam reforming reactions. The heat required for endothermic reforming reactions is provided by exothermic oxidizing reactions occurring inside the OTM reactors of the pack. At a thermo-neutral point the heat released by exothermic reactions matches the heat required to support endothermic reactions and heat losses in the pack. The method modulates the flow rate of hydrocarbon-containing feed and/or steam-to-carbon ratio of the combined feed to the pack to maintain the surface temperature of oxygen transport membrane reactors below a target maximum temperature. The syngas product oxygen-to-carbon ratio is maintained within a desired target range such that the OTM based reforming system is operated close to thermo-neutral point.
摘要:
A system and method for air temperature control in an oxygen transport membrane based reactor is provided. The system and method involves introducing a specific quantity of cooling air or trim air in between stages in a multistage oxygen transport membrane based reactor or furnace to maintain generally consistent surface temperatures of the oxygen transport membrane elements and associated reactors. The associated reactors may include reforming reactors, boilers or process gas heaters.