Nexant, Inc.

Gas Research Institute

Bechtel Corporation

Tan-Ping Chen

A system for generating electricity which includes an internal manifold fuel cell stack having an anode fuel gas duct, an anode exhaust gas duct, a cathode air duct and a cathode exhaust duct and a plenum having a fuel gas inlet, an anode exhaust gas outlet, an air inlet and a cathode exhaust gas outlet, which plenum is adapted to deliver a fuel gas and air to the internal manifold fuel cell stack. At least one air preheat panel is provided having two parallel planar surfaces disposed proximate and parallel to the internal manifold fuel cell stack and forming at least one air duct between the two parallel planar surfaces, which at least one air duct extends parallel to the two planar surfaces and has at least one cold air inlet and at least one preheated air outlet. The preheated air outlet is in fluid communication with the cathode air duct. In accordance with one embodiment, the internal manifold fuel cell stack, plenum and the at least one air preheat panel are all disposed within a housing.

System for generating electricity

A fuel cell stack (,) includes at least first and second cells (,) and a separator assembly (,). Each cell includes an anode (,), a cathode (,) and electrolyte (,) between them. The separator assembly includes a fluid separator (,) having a fuel side, an oxidant side, an anode spacer element (,) between the fuel side and the anode of the first cell and a cathode spacer element (,) between the oxidant side and the cathode of the second cell. The separator assembly further includes a cathode exhaust passageway(,), having an exhaust inlet (,) at the central region (,) of the cathode spacer element, and an anode feed passageway (,), including a continuous loop anode feed tube, located spaced apart from the cell peripheral edge, with radially inwardly and outwardly directed fuel outlets (,). An air deflector (,) helps prevent radially inwardly moving air from contacting the anode while permitting the air access to the peripheral edge (,) of the cathode spacer element. An anode recycle passageway (,) has a recycle inlet (,) fluidly coupled to spent fuel, including residual fuel and cell reaction product water, at the center of the anode, and a recycle outlet (,), within the anode feed passageway, so that the cell reaction product water can be used as a steam source for internal reforming.

Fuel cell stack system and operating method

A fuel cell assembly (,) includes a vessel (,) containing a gas-permeable, porous housing (,). A fuel cell stack (,), including cells (,) and interconnect plates (,), is contained within the porous housing. Each interconnect plate has oxidant and fuel sides (,) adjacent to the cathode (,) and anode (,) of adjacent cells. Fuel (,) is supplied to the fuel side at positions (,) midway between the center (,) and the periphery (,) of the fuel side. Reaction products (,) are withdrawn from the center of the fuel side. Flue gas (,) is withdrawn from the center (,) of the oxidant side. Air is preheated as it passes through the porous housing to the fuel cell stack. The preheated air combusts residual fuel (,) flowing radially outwardly from the periphery of the stack to further heat the air to the stack operating temperature to eliminate any external preheating of the air. Corrugations (,) on the interconnect plates act as flow deflectors and form the electrical contact surfaces for adjacent cells. The fuel cell stack is preferably oriented horizontally and is allowed to thermally expand and contract in a substantially free manner, to minimize damage to the cells, until the fuel cell stack is close to an operating temperature.

Fuel cell assembly

A fuel cell assembly (2) includes a vessel (4) containing a gas-permeable, porous housing (16). A fuel cell stack (14), including cells (42) and interconnect plates (44), is contained within the porous housing. Each interconnect plate has oxidant and fuel sides (64, 60) adjacent to the cathode (58) and anode (62) of adjacent cells. Fuel (68) is supplied to the fuel side at positions (78) midway between the center (82) and the periphery (80) of the fuel side. Reaction products (90) are withdrawn from the center of the fuel side. Flue gas (100) is withdrawn from the center (98) of the oxidant side. Air is preheated as it passes through the porous housing to the fuel cell stack. The preheated air combusts residual fuel (110) flowing radially outwardly from the periphery of the stack to further heat the air to the stack operating temperature to eliminate any external preheating of the air. Corrugations (66, 67) on the interconnect plates act as flow deflectors and form the electrical contact surfaces for adjacent cells. The fuel cell stack is preferably oriented horizontally and is allowed to thermally expand and contract in a substantially free manner, to minimize damage to the cells, until the fuel cell stack is close to an operating temperature.

Growing community of inventors

Walnut Creek, CA, United States of America

Tan-Ping Chen