United Technologies Corporation

International Fuel Cells, LLC

Robert J Misage

Albert P Grasso

Paul R Margiott

Glenn W Scheffler

Herbert J Setzer

George T Suljak, Jr

Edmund K Parenti, Jr

Joseph J Faitani

George W Austin, Jr

Daniel L D'Aquila

Bryan J Dec

Terry J Chase

A fuel cell stack includes a plurality of fuel cells juxtaposed with one another in the stack and each including a pair of plate-shaped anode and cathode electrodes that face one another, and a quantity of liquid electrolyte present at least between the electrodes. A number of separator plates that are substantially impermeable to liquids but wettable by electrolyte is interposed between respective successive electrodes of adjacent ones of the fuel cells. Each such separator plate has edge portions situated at a periphery of the fuel stack and having a peripheral surface, and marginal surfaces respectively facing the successive electrodes and forming respective interfaces therewith. Migration of any electrolyte that may be present at one of the interfaces to the other of the interfaces and thus from one to the other of the adjacent fuel cells is prevented by providing a layer of a material that is non-wettable by the electrolyte at least on the peripheral surface of the separator plate, but advantageously also on the marginal surfaces.

Fuel cell stack liquid electrolyte migration prevention arrangement

In order to achieve good stack water chemistry and minimize corrosion in a fuel cell stack water cooling loop, the oxygen concentration in the water must remain within a relatively narrow range. Stacks using steam separators produce water in the separators which is relatively devoid of oxygen. Makeup water is used to replace the steam lost from the separator, which makeup water is relatively rich in oxygen. The flow rates of the makeup water and steam separator water are controlled to produce a proper oxygen concentration in the recirculated coolant water. Some of the makeup water will be added directly into the steam separator so that it will be stripped of oxygen and the rest will be added subsequent to the steam separator.

Controlling oxygen concentrations in fuel cell cooling water loops

A heat exchanger uses the heat from processed fuel gas from a reformer for a fuel cell to superheat steam, to preheat raw fuel prior to entering the reformer and to heat a water-steam coolant mixture from the fuel cells. The processed fuel gas temperature is thus lowered to a level useful in the fuel cell reaction. The four temperature adjustments are accomplished in a single heat exchanger with only three heat transfer cores. The heat exchanger is preheated by circulating coolant and purge steam from the power section during startup of the latter.

Heat exchanger for fuel cell power plant reformer

To more uniformly distribute heat to the plurality of catalyst tubes in a catalytic reaction furnace, the burner disposed in the furnace above the tops of the tubes includes concentric primary and secondary annular fuel and air outlets. The fuel-air mixture from the primary outlet is directed towards the tubes adjacent the furnace wall, and the burning secondary fuel-air mixture is directed horizontally from the secondary outlet and a portion thereof is deflected downwardly by a slotted baffle toward the tubes in the center of the furnace while the remaining portion passes through the slotted baffle to another baffle disposed radially outwardly therefrom which deflects it downwardly in the vicinity of the tubes between those in the center and those near the wall of the furnace.

Catalytic reactor with improved burner

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Manchester, CT, United States of America

Robert J Misage