International Fuel Cells, LLC

Utc Fuel Cells, LLC

United Technologies Corporation

Utc Power Corporation

Glenn W Scheffler

Paul R Margiott

Richard D Breault

Robert R Fredley

Albert P Grasso

Leslie L Van Dine

Peter F Foley

Sean Haggerty

Paul A Grubb

Peter A Golovchenko

Michael L Perry

Carl Anthony Reiser

Richard A Sederquist

John L Preston

Donald L Maricle

Deliang Yang

Thomas J Corrigan

Jung S Yi

Herbert J Setzer

Francis J Luczak

Craig R Schroll

Stanley P Bonk

Margaret M Steinbugler

Zakiul Kabir

George Vartanian

Robert J Misage

Daniel W Beal

Martin L Abrams

Alfred P Meyer

Edmund K Parenti, Jr

Daniel L D'Aquila

Francis A Kocum

Valerie A Maston

Brian F Dufner

Karen L Parenti

Christopher W Callahan

Christopher R Teeling

Yasar Tanrikut

A method for operating a fuel cell power plant to supply power to an internal load and an external load, includes the steps of evaluating power needs of the internal and external loads to determine a fixed IDC value sufficient to supply the needs; providing auxiliary power to the internal load and output power to the external load so as to maintain operation of the fuel cell power plant at the fixed IDC value; and adjusting at least one of the auxiliary power to the internal load and output power to the external load so as to maintain operation of the fuel cell power plant at the fixed IDC value. Operation within a preselected voltage range is also provided.

Fixed IDC operation of fuel cell power plant

A method for operating a fuel cell power plant to supply power to an internal load and an external load, includes the steps of evaluating power needs of the internal and external loads to determine a fixed IDC value sufficient to supply the needs; providing auxiliary power to the internal load and output power to the external load so as to maintain operation of the fuel cell power plant at the fixed IDC value; and adjusting at least one of the auxiliary power to the internal load and output power to the external load so as to maintain operation of the fuel cell power plant at the fixed IDC value.

Water flow field inlet manifolds () are disposed at the fuel cell stack () base. Water flow field outlet manifolds () are located at the fuel cell stack top. Outlet and inlet manifolds are interconnected () so gas bubbles leaking through the porous water transport plate cause flow by natural convection, with no mechanical water pump. Variation in water level within a standpipe () controls () the temperature or flow of coolant. In another embodiment, the water is not circulated, but gas and excess water are vented from the water outlet manifolds. Water channels () may be vertical. A hydrophobic region () provides gas leakage to ensure bubble pumping of water. An external heat exchanger () maximizes water density differential for convective flow.

PEM fuel cell passive water management

A fuel cell system that includes fuel processing components, such as a reformer and shift converter, for converting an organic fuel to hydrogen, is shut-down by disconnecting the fuel cell from its load and purging the fuel processing components of residual hydrogen with a flow of air. The purge air may be forced through the components in series or in parallel, using a blower; or, the purge air may be allowed to enter the components through a low inlet, whereupon the air rises through the components by natural circulation and exits through a high outlet, along with the residual hydrogen.

Shut-down procedure for fuel cell fuel processing system

A proton exchange membrane (PEM) fuel cell includes fuel and oxidant flow field plates ( ) having fuel and oxidant channels ( ), and water channels, the ends ( ) of which that are adjacent to the corresponding reactant gas inlet manifold ( ) are dead ended, the other ends ( ) draining excess water into the corresponding reactant gas exhaust manifold ( ). Flow restrictors ( ) maintain reactant gas pressure above exit manifold pressure, and may comprise interdigitated channels ( ). Solid reactant gas flow field plates have small holes ( ) between reactant gas channels ( ) and water drain channels ( ). In one embodiment, the fuel cells of a stack may be separated by either coolant plates ( ) or solid plates ( ) or both. In a second embodiment, coolant plates ( ) have weep holes ( ) that inject water into the ends ( ) of the reactant gas water channels which are in the region of the inlet manifold ( ), thereby assuring humidification of the reactants.

Passive water management fuel cell

A procedure for shutting down an operating fuel cell system that recirculates a portion of the anode exhaust in a recycle loop, includes disconnecting the primary load from the external circuit, stopping the flow of air to the cathode, and applying an auxiliary resistive load across the cells to reduce and/or limit cell voltage and reduce the cathode potential while fuel is still flowing to the anode and the anode exhaust is recirculating. The fuel flow is then stopped, but the anode exhaust continues to be circulated in the recycle loop to bring the hydrogen therein into contact with a catalyst in the presence of oxygen to convert the hydrogen to water, such as in a catalytic burner. The recirculating is continued until substantially all the hydrogen is removed. The cell may then be completely shut down. No inert gas purge is required as part of the shut-down process.

Procedure for shutting down a fuel cell system having an anode exhaust recycle loop

A method and system are provided for controlling a fuel cell power plant ( ). A demand signal (M ) representing the anticipated current/power required by the electrical load(s) is provided. A current signal (I ) representative of the actual current drawn by the load(s) ( ) is provided. The greater of the demand signal (M ) and the current signal (I ) is selected ( ) and utilized to provide a control signal (Mx, Mx&prime;, Mx&Prime;) for regulating one or more of the reactants and coolant ( ). One or more status signals (Xp, Xp&prime;, Xp&Prime;, Vap) indicative of the status of a regulated one of more of the reactant/coolant and/or a respective operating process effected, is provided. Each status signal is transformed to a respective load capability signal ( ). The lesser of the demand signal (M ) and each of the load capability signals ( ) is selected ( ) to provide an output signal (M ) for commensurately controlling a system load ( ).

Predictive control arrangement for load-following fuel cell-powered applications

A fuel cell power plant having a fuel cell assembly includes an anode provided with a fuel stream, a cathode provided with an oxidant stream, an ion exchange membrane oriented between said anode and said cathode, and a coolant loop circulating a coolant stream in fluid communication with the fuel cell assembly. An oxidant source is utilized for supplying the fuel cell assembly with the oxidant stream at a predetermined pressure, while a coolant regulator oriented along the coolant loop lowers the coolant stream to a subambient pressure prior to the coolant stream coming into fluid communication with the fuel cell assembly.

Subambient pressure coolant loop for a fuel cell power plant

A compact and efficient fuel reformer which is operable to produce a hydrogen-enriched process fuel from a raw fuel such as natural gas, or the like includes a compact array of catalyst tubes which are contained in a heat-insulated housing. The catalyst tube array preferably includes a multitude of catalyst tubes that are arranged in a hexagonal array. The housing includes internal hexagonal thermal insulation so as to ensure even heating of the catalyst tubes. The diameter of the tubes is sized so that spacing between adjacent tubes in the array can be minimized for efficient heat transfer. The interior of each of the catalyst tubes includes a hollow dead-ended central tube which serves as a fines trap for collecting catalyst fines that may become entrained in the fuel stream. The catalyst tubes are also provided with an upper frusto-conical portion which serves to extend the catalyst bed and provide a catalyst reserve. The assembly includes a side-fired startup burner which allows for an improved diffusion burner orifice array at the top of the reformer. The catalyst tubes are supported by side walls of the assembly in a manner that stabilizes the tubes in the assembly. In the assembly, the internal transverse manifold plates are tied together by portions of the tube assemblies so as to form a composite beam that supports the weight of the catalyst tube array.

Hydrocarbon fuel gas reformer assembly for a fuel cell power plant

A fuel cell (,), having a proton exchange membrane (,), an anode and a cathode, and cathode and anode water transport plates (,), includes a water capillary edge seal to optimize and greatly improve fuel cell operation without the need for additional seals or impregnation of the water transport plates. The water filled porous bodies of the water transport plates (,) use the capillary forces of the water, which is a product of the electrochemical reaction of the fuel cell (,) and the preferred coolant, to prevent gas intrusion into the water system and over board leakage of the gases as well as the resultant hazardous mixture of gaseous fuel and oxidizing gas.

Fuel cell with water capillary edge seal

The present invention discloses a corrosion resistant fuel cell in which an ion impermeable protective layer is positioned over at least a portion of the noncatalyzed carbon based components. This layer prevents reactant ions or molecules form reaching localized high potential areas of these components and corroding the carbon material.

Corrosion resistant fuel cell assembly

Ammonia which is found in fuel cell fuel gases is removed therefrom by passing the fuel gas stream through a scrubber bed of porous carbon pellets containing phosphoric acid. The ammonia reacts with the phosphoric acid in the scrubber bed to form ammonium phosphate compounds which remain in the scrubber bed. The ammonia content of the fuel gas stream is thus lowered to a concentration of about one ppm or less. By maintaining the temperature of the fuel gas stream passing through the scrubber bed in a range of about 400.degree. F. to about 450.degree. F. sufficient phosphoric acid will also be evaporated from the scrubber bed to replace acid electrolyte lost during operation of the power plant. Adjustments in the temperature of the fuel gas flowing through the scrubber may be made in order to match electrolyte losses which occur during different operating phases of the power plant. The scrubber formed in accordance with this invention thus serves two functions, one being to remove ammonia from the fuel gas stream, and the other being to replenish electrolyte lost in the power plant during normal operation thereof.

System for treatment of acid fuel cell fuel gas stream

The cell stack assembly of a fuel cell power plant is provided with a cooling system which provides optimum cell operating temperatures across each cell in the stack and also produces an optimum amount of steam. The cooling system includes at least one bypass through which a fraction of the coolant is fed from the coolant inlet side of the stack to the coolant outlet side of the stack. The bypass ensures that a fraction of the coolant is not heated to its target operating temperatures as it passes through the stack. This results in a more uniform cell operating temperature profile from the coolant inlet to the coolant outlet side of each cell; and also results in a lessening of excess steam production in the power plant.

System and method for providing optimum cell operating temperatures and

A simplified solid polymer electrolyte fuel cell power plant utilizes porous conductive separator plates having central passages which are filled with circulating coolant water. The coolant water passes through a heat exchanger which rejects heat generated in the power plant. Water appearing on the cathode side of each cell membrane is pumped into the water circulation passages through the porous oxidant reactant flow field plates by a positive .DELTA.P created between the cathode reactant flow field of each cell and the coolant water circulation passages between each cell. In order to create the desired .DELTA.P, at least one of the reactant gas streams will be referenced to the coolant water loop so as to create a coolant loop pressure which is less than the referenced reactant gas stream pressure. Excess water is removed from the coolant water stream. The system can operate at ambient or at elevated pressures. Each cell in the power plant is individually cooled on demand, and the power plant does not require a separate cooling section or reactant stream humidifying devices.

Water management system for solid polymer electrolyte fuel cell power

A fuel cell (10) system in which a nitrogen (N.sub.2) gas is used on the anode section (11) and a nitrogen/oxygen (N.sub.2 /O.sub.2) gaseous mix is used on the cathode section (12) to maintain the cathode at an acceptable voltage potential during adverse conditions occurring particularly during off-power conditions, for example, during power plant shutdown, start-up and hot holds. During power plant shutdown, the cathode section is purged with a gaseous mixture of, for example, one-half percent (0.5%) oxygen (O.sub.2) and ninety-nine and a half percent (99.5%) nitrogen (N.sub.2) supplied from an ejector (21) bleeding in air (24/28) into a high pressure stream (27) of nitrogen (N.sub.2) as the primary of majority gas. Thereafter the fuel gas in the fuel processor (31) and the anode section (11) is purged with nitrogen gas to prevent nickel (Ni) carbonyl from forming from the shift catalyst. A switched dummy electrical load (30) is used to bring the cathode potential down rapidly during the start of the purges. The 0.5%/99.5% O.sub.2 N.sub.2 mixture maintains the cathode potential between 0.3 and 0.7 volts, and this is sufficient to maintain the cathode potential at 0.3 volts for the case of H.sub.2 diffusing to the cathode through a 2 mil thick electrolyte filled matrix and below 0.8 volts for no diffusion at open circuit conditions. The ejector meters high pressure nitrogen gas with a choked orifice or venturi and uses the energy in the gas from the orifice or venture to suck ambient air into the nitrogen stream before entering the cathode section.

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Tolland, CT, United States of America

Glenn W Scheffler