Abstract: The invention reduces free water volume in a fuel cell power plant so support systems of the plant are freeze tolerant. The fuel cell power plant includes a coolant system having a sealed cooler plate that circulates an antifreeze coolant in heat exchange with a fuel cell and that collects fuel cell water; a water vapor removal system that removes water vapor from the antifreeze coolant to regulate the antifreeze concentration; and a start-up system having a start-up heat exchanger and a start-up valve that selectively direct heated antifreeze coolant into the cooler plate for a start-up procedure. The plant may also include a fuel processing system that utilizes the removed water vapor, and that is in heat exchange with the start-up heat exchanger. The antifreeze coolant is a low vapor pressure solution, such as an alkanetriol or polyethylene glycol.

Abstract: A fuel cell system includes a fuel cell for reacting a hydrogen rich gas; a fuel processor system for converting a hydrocarbon fuel-steam mixture into said hydrogen rich gas; and a system for preparing the hydrocarbon fuel-steam mixture which includes (a) structure for superheating a hydrocarbon fuel so as to provide a superheated fuel, and (b) structure for mixing water with the superheated fuel so as to provide the hydrocarbon fuel-steam mixture.

Abstract: 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.

Abstract: A fuel cell power plant having a plurality of functionally integrated components including a fuel cell assembly provided with a fuel stream, an oxidant stream and a coolant stream. The fuel cell power plant functionally integrates a mass and heat recovery device for promoting a transfer of thermal energy and moisture between a first gaseous stream and a second gaseous stream, and a burner for processing the fuel exhausted from the fuel cell assembly during operation thereof. A housing chamber is utilized which accepts the oxidant stream exhausted from the fuel cell assembly after the exhausted oxidant stream has merged with a burner gaseous stream exhausted from the burner. The resultant merged airflow is subsequently directed to the housing chamber and to the mass and heat recovery device as the first gaseous stream.

Abstract: A direct antifreeze cooled fuel cell power plant is disclosed. The plant includes at least one fuel cell a thermal management system that directs flow of a cooling fluid for controlling heat within the plant, including a direct antifreeze solution passing through the water transport plate. The plant also integrates the direct antifreeze solution with a direct mass and heat transfer device, a water treatment system, and a steam injection system so that the direct antifreeze solution minimizes problems related to operation of the plant in sub-freezing conditions. A preferred antifreeze solution is an alkanetriol selected from the group consisting of glycerol, butanetriol, and pentanetriol. The direct antifreeze solutions minimize movement of the antifreeze as a vapor out of a water transport plate into contact with cathode or anode catalysts, and also minimize direct antifreeze solution loss from other power plant systems.

Abstract: A coolant treatment system for a direct antifreeze cooled fuel cell power plant including a degassifier for providing interaction between an oxidant and an antifreeze solution which has circulated throughout the fuel cell power plant so that dissolved gases within the antifreeze solution are removed. The fuel cell power plant is configured to allow the antifreeze solution to be in direct fluid communication with the fuel cell assemblies comprising the fuel cell power plant.

Abstract: 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.

Abstract: 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.

Abstract: An operating system for a direct antifreeze cooled fuel cell power plant is disclosed for producing electrical energy from reducing and process oxidant fluid reactant streams. The system includes at least one fuel cell for producing electrical energy from the reducing and oxidant fluid streams; fuel processing components for processing a hydrocarbon fuel into the reducing fluid; a thermal management system that directs flow of a cooling fluid for controlling heat within the plant including a porous water transport plate adjacent and in fluid communication with a cathode catalyst of the fuel cell; a direct antifreeze solution passing through the water transport plate; and, a split oxidant passage that directs the process oxidant stream into and through the fuel cell.

Abstract: An improved water management system for PEM fuel cells is provided. Catalyst layers are disposed on both sides of a proton exchange membrane. Porous plates are positioned adjacent the catalyst layers. Water transport plates are positioned adjacent the porous plates and the reactant gas are humidified at their inlets, in one embodiment by fins, while moisture is removed in the fuel flow path and at the oxidant outlet, in one embodiment by other fins.

Abstract: A direct antifreeze cooled fuel cell power plant system is disclosed for producing electrical energy from reducing and process oxidant fluid reactant streams. The system includes at least one fuel cell for producing electrical energy from the reducing and oxidant fluid streams; a thermal management system that directs flow of a cooling fluid for controlling temperature within the plant including a porous water transport plate adjacent and in direct fluid communication with a cathode catalyst of the fuel cell; a direct antifreeze solution passing through the water transport plate; and, fuel processing components secured in fluid communication with the thermal management system for processing a hydrocarbon fuel into the reducing fluid and for controlling a concentration of a direct antifreeze in the direct antifreeze solution.

Abstract: The invention is an operating system for a fuel cell power plant that includes at least one fuel cell for producing electrical energy from a reducing and oxidant fluid and fuel processing components including a reformer and a burner for processing a hydrocarbon fuel into the reducing fluid, and a direct mass and heat transfer device secured in fluid communication with both a process oxidant stream and a plant exhaust passage, so that the device directly transfers mass such as water exiting the plant in a plant exhaust stream back into the plant within the process oxidant stream. The invention also includes a split oxidant passage that directs the process oxidant stream through the fuel cell and a reformer feed portion of the process oxidant stream into fluid communication with the fuel processing components.

Abstract: The invention is a humidification system for a fuel cell power plant. The system includes at least one fuel cell comprising a coolant flow field adjacent the cathode flow field. The coolant flow field includes a coolant inlet, a coolant outlet, and a split-path coolant distribution channel between the coolant inlet and outlet. The split-path distribution channel directs some of the coolest portion of the coolant stream to flow adjacent the cathode inlet and some of the coolest portion to flow adjacent the cathode outlet. The humidification system lowers a temperature of the process oxidant stream adjacent the cathode inlet, thereby increasing relative humidity of the stream in the cathode flow field adjacent the cathode inlet.

Abstract: The invention is a water retention system for a fuel cell power plant having at least one fuel cell and a coolant loop with a coolant reservoir and coolant passages for directing a coolant fluid through the fuel cell. An air conditioning unit is provided for directing a refrigerant to a first heat exchanger that cools secondary process air and for directing water condensed from the secondary process air to the coolant reservoir. The air conditioning unit also directs the refrigerant to a second heat exchanger that cools the coolant fluid within the coolant loop, and to a third heat exchanger that cools a plant exhaust stream exiting the plant. Water condensed from the plant exhaust is also directed from the third heat exchanger into the coolant reservoir.

Abstract: A method and apparatus for removing contaminants from the coolant supply of a fuel cell power plant, wherein coolant which has been exhausted from the fuel cell power plant is fed to an oxidant manifold. The exhausted coolant interacts with the oxidant flowing through the oxidant manifold, thereby effectuating removal of contaminants from the exhausted coolant.

Abstract: A water treatment system for a fuel cell stack, wherein a degassifier provides for interaction between an oxidant and a coolant which has circulated throughout the fuel cell stack so that dissolved gases within the circulated coolant are removed.

Abstract: The invention is a pressurized water recovery system for a fuel cell power plant including at least one fuel cell having an electrolyte between anode and cathode electrodes for producing an electric current from a reducing fluid and an oxidant stream. A coolant loop directs a coolant fluid from a reservoir through a coolant passage to the fuel cell and back to the reservoir, and the coolant loop also receives coolant fluid through water lines secured between condensing heat exchangers and the coolant reservoir. A process exhaust passage directs a process exhaust stream from adjacent the cathode and anode electrodes out of the fuel cell and into a condensing heat exchanger. Whenever the power plant is under coolant stress, a process exhaust valve selectively directs a portion of the process exhaust stream out of the process exhaust passage to a supercharger that pressurizes the received portion of the process exhaust stream and directs the pressurized portion to a pressurized condensing heat exchanger.

Abstract: The present invention relates to a method and apparatus for creating steam from the cooling stream of a proton exchange membrane (PEM) fuel cell. As the cooling stream exits the PEM fuel cell, a portion of the cooling fluid is extracted from the circulating cooling stream, thereby creating a secondary stream of cooling fluid. This secondary stream passes through a restriction, which decreases the pressure of the secondary stream to its saturation pressure, such that when the secondary stream enters a flash evaporator it transforms into steam. Creating steam from the cooling stream of a PEM fuel cell power plant provides the fuel processor with a co-generated source of steam without adding a significant amount of auxiliary equipment to the power plant.

Abstract: A mass transfer composite membrane for use with a fuel cell power plant includes a transfer medium core between opposed, rigid, porous support sheets. An inlet surface of the composite membrane is positioned in contact with an oxidant inlet stream of a fuel cell power plant, and an opposed exhaust surface of the composite membrane is positioned in contact with an exhaust stream exiting the fuel cell power plant to recover mass such as water from the exhaust stream and transfer it into the oxidant inlet stream entering the fuel cell. The transfer medium core may comprise any of a variety of materials for sorbing a fluid substance consisting of polar molecules such as water molecules from a fluid stream consisting of polar and non-polar molecules. A preferred transfer medium core is an ionomeric membrane such as a water saturated polyfluorosulfonic acid ionomer membrane.

Abstract: A mass and heat recovery system for a fuel cell power plant includes at least one fuel cell for producing electrical energy, hydrocarbon fuel processing components for producing a hydrogen rich reducing fluid for the fuel cell, and a direct mass and heat transfer device for recovering mass and heat such as water vapor leaving the plant. The fuel processing components include an auxiliary burner that provides heat to generate steam and a reformer that receives the steam mixed with a hydrocarbon fuel along with a small amount of air and converts the mixture to a hydrogen rich stream appropriate for supplying hydrogen to the anode electrode.