A fuel cell hot box for improving the system efficiency of a fuel cell. Fuel cell stack parts, an after burner, a reformer, an air pre-heating zone, and a fuel-heat exchanger are provided in a housing allowing heat of the fuel cell stack parts and heat of combustion gas generated in the after burner to be used for reforming, preheating fuel and preheating air at the same time to avoid wasting energy. The fuel cell stack parts under thermal stress can be cooled to improve durability of the stack parts to increase a lifetime of a total system, and the stack parts can share the central chamber part to simplify a structure of the fuel cell hot box. In addition, the reformer includes an opening and closing unit to properly distribute the high-temperature combustion gas so that a reforming ratio is adjustable according to an operating condition of the fuel.

The present invention provides a fuel cell cap that includes a flanged edge region in which a gasket is positioned, and which is adapted to be sealingly fit over the edge of fuel cell and successive heat energy transmitting sections that concentrate the heat energy for ultimate emission. A dome-shaped first region is integral with and positioned radially inward from the flanged edge region followed by a first stack region of cylindrical cross-sectional shape that is integral with and extending upwardly from the dome-shaped first region. Next, a second stack region of cylindrical cross-section shape extends upwardly from the first stack region and is of a second diameter smaller than the first diameter. Finally, an inwardly tapering region extends upwardly from the second stack region and emits the heat energy from the cap.

A fuel cell system includes a reformer, fuel cell stacks, and an exhaust-gas combustor. The reformer has a tubular shape extending in an axial direction and reforms raw fuel into combustion gas. The fuel cell stacks generate electric power from the fuel gas and oxidant gas. The fuel cell stacks are arranged radially outward of the reformer in a circumferential direction to face the reformer in a radial direction. The exhaust-gas combustor burns fuel gas that is not used and included in exhaust gas from the fuel cell stacks. The exhaust-gas combustor is arranged radially inward of the reformer to face the reformer in the radial direction. Each fuel cell stack includes flat plate type cells stacked in the radial direction. This achieves downsizing of the fuel cell system.

A fuel cell system includes a reformer, fuel cell stacks, and an exhaust-gas combustor. The reformer has a tubular shape extending in an axial direction and reforms raw fuel into combustion gas. The fuel cell stacks generate electric power from the fuel gas and oxidant gas. The fuel cell stacks are arranged radially outward of the reformer in a circumferential direction to face the reformer in a radial direction. The exhaust-gas combustor burns fuel gas that is not used and included in exhaust gas from the fuel cell stacks. The exhaust-gas combustor is arranged radially inward of the reformer to face the reformer in the radial direction. Each fuel cell stack includes flat plate type cells stacked in the radial direction. This achieves downsizing of the fuel cell system.

A fuel cell hot box for improving the system efficiency of a fuel cell. Fuel cell stack parts, an after burner, a reformer, an air pre-heating zone, and a fuel-heat exchanger are provided in a housing allowing heat of the fuel cell stack parts and heat of combustion gas generated in the after burner to be used for reforming, preheating fuel and preheating air at the same time to avoid wasting energy. The fuel cell stack parts under thermal stress can be cooled to improve durability of the stack parts to increase a lifetime of a total system, and the stack parts can share the central chamber part to simplify a structure of the fuel cell hot box. In addition, the reformer includes an opening and closing unit to properly distribute the high-temperature combustion gas so that a reforming ratio is adjustable according to an operating condition of the fuel.

A fuel cell hot box for improving the system efficiency of a fuel cell. Fuel cell stack parts, an after burner, a reformer, an air pre-heating zone, and a fuel-heat exchanger are provided in a housing allowing heat of the fuel cell stack parts and heat of combustion gas generated in the after burner to be used for reforming, preheating fuel and preheating air at the same time to avoid wasting energy. The fuel cell stack parts under thermal stress can be cooled to improve durability of the stack parts to increase a lifetime of a total system, and the stack parts can share the central chamber part to simplify a structure of the fuel cell hot box. In addition, the reformer includes an opening and closing unit to properly distribute the high-temperature combustion gas so that a reforming ratio is adjustable according to an operating condition of the fuel.

A fuel cell system and method for using a peak shaving gas, the system including: a fuel inlet configured to receive fuel from a fuel source; a catalytic partial oxidation (CPOx) reactor configured to at least partially oxidize the fuel during startup of the system; a blower configured to provide air to the CPOx reactor; a gas analyzer configured to determine a composition of fuel provided to the CPOx reactor from the fuel inlet; an oxidation catalyst configured to reduce an O.sub.2 content of fuel received from the CPOx reactor; a reforming catalyst configured to partially reform fuel received from the oxidation catalyst; and a stack of fuel cells configured to generate electricity using fuel received from the reforming catalyst.

A fuel cell system includes a reformer, fuel cell stacks, and an exhaust-gas combustor. The reformer has a tubular shape extending in an axial direction and reforms raw fuel into combustion gas. The fuel cell stacks generate electric power from the fuel gas and oxidant gas. The fuel cell stacks are arranged radially outward of the reformer in a circumferential direction to face the reformer in a radial direction. The exhaust-gas combustor burns fuel gas that is not used and included in exhaust gas from the fuel cell stacks. The exhaust-gas combustor is arranged radially inward of the reformer to face the reformer in the radial direction. Each fuel cell stack includes flat plate type cells stacked in the radial direction. This achieves downsizing of the fuel cell system.

A fuel cell system includes a reformer, fuel cell stacks, and an exhaust-gas combustor. The reformer has a tubular shape extending in an axial direction and reforms raw fuel into combustion gas. The fuel cell stacks generate electric power from the fuel gas and oxidant gas. The fuel cell stacks are arranged radially outward of the reformer in a circumferential direction to face the reformer in a radial direction. The exhaust-gas combustor burns fuel gas that is not used and included in exhaust gas from the fuel cell stacks. The exhaust-gas combustor is arranged radially inward of the reformer to face the reformer in the radial direction. Each fuel cell stack includes flat plate type cells stacked in the radial direction. This achieves downsizing of the fuel cell system.

A solid oxide fuel cell (SOFC) system includes high thermal conductivity materials such as copper to increase thermal energy transfer by thermal conduction. The copper is protected from oxidation by nickel electroplating and protected from thermal damage by providing oxidation resistant liners inside combustion chambers.