摘要:
An exothermic reaction and an endothermic reaction are thermally combined in a reactor having at least one oxygen selective ion transport membrane that provides the exothermic reaction with oxygen from an oxygen-containing gas such as air. The thermal requirements of the endothermic reaction are satisfied by the exothermic reaction. Dependent on the reactor design employed, the exothermic and endothermic reactions may be gaseously combined.
摘要:
A reactor comprising: a hollow shell defining a hermetic enclosure; a plurality of tube sheets disposed within said hermetic enclosure, a first one of said plurality of tube sheets defining a first chamber; at least one reaction tube each having a first end and an opposing second end, said first end being fixedly attached and substantially hermetically sealed to one end of said plurality of tube sheets and opening into said first chamber, the second end being axially unrestrained; each of said reaction tubes is comprised of an oxygen selective ion transport membrane with an anode side wherein said oxygen selective ion transport membrane is formed from a mixed conductor metal oxide that is effective for the transport of elemental oxygen at elevated temperatures and at least a portion of said first and second heat transfer sections are formed of metal; each of said reaction tubes includes first and second heat transfer sections and a reaction section, said reaction section disposed between said first and second heat transfer sections; a reforming catalyst disposed about said anode side of said oxygen selective ion transport membrane; a first process gas inlet; a second process gas inlet; and, a plurality of outlets.
摘要:
A method for determining the water transfer in a water vapor transfer unit of a fuel cell system that employs a model based approach. The method includes determining a capacity ratio of wet streams and dry streams flowing through the water vapor transfer unit, determining the number of mass transfer units of the water vapor transfer unit, estimating a mass transfer effectiveness value given the capacity ratio and the number of mass transfer units for the water vapor transfer unit, and determining the amount of water transferred in the water vapor transfer unit using the mass transfer effectiveness value, the mass flow rates on a dry basis of the dry stream and the wet stream, and the mass flow rates of water of the dry inlet stream and the wet inlet stream.
摘要:
A system for the slow purge of a fuel cell stack. A pump can be used to keep the coolant circulating, so that the stack, an associated radiator, and coolant plumbing therebetween are maintained at the same temperature. The heat from the stack, liquid coolant, and radiator can be used to provide the heat of vaporization of the liquid in the stack, and the liquid water can be removed from the stack as water vapor. Because the air flow rate is relatively low, there is sufficient time for the water to vaporize and for the air to come to the same temperature as the stack, which is also facilitated by high surface area for heat transfer. Purge air can be drawn into the stack through the radiator, via a purge air blower, which preheats the air to help avoid frigid air contacting the stack.
摘要:
A bipolar plate for a fuel cell is provided that includes a pair of unipolar plates having a separator plate disposed therebetween. One of the unipolar plates is produced from a porous material to minimize cathode transport resistance at high current density. A fuel cell stack including a fuel cell and the bipolar plate is also provided.
摘要:
A fuel cell system is described having a fuel cell stack including a PEM fuel cell having an anode and a cathode, the fuel cell stack further including an anode outlet and an anode inlet, a hydrogen storage device in communication with the anode inlet and configured to supply a hydrogen gas to the fuel cell stack, and an accumulation reservoir in communication with the anode outlet of the fuel cell stack. The accumulation reservoir is configured to accumulate a quantity of water and an exhaust stream including the hydrogen gas during a purge event and resupply the exhaust stream to the fuel cell stack after the purge event is complete. The accumulation reservoir can be a second fuel cell stack. A method of operating the fuel cell system is also provided.
摘要:
A bipolar plate for a fuel cell is provided that includes a pair of unipolar plates having a separator plate disposed therebetween. One of the unipolar plates is produced from a porous material to minimize cathode transport resistance at high current density. A fuel cell stack including a fuel cell and the bipolar plate is also provided.
摘要:
A model uses various operating characteristics of a fuel cell to predict the relative humidity profile that is occurring within the fuel cell as a function of the reaction progress. The model is used to predict the relative humidity profile that will occur in response to changes to one or more of the operating characteristics of the fuel cell. A high frequency resistance of the fuel cell can also be used as a measure that is indicative of the humidity within the fuel cell. The model and/or the high frequency resistance can be used in a closed-loop feedback system to control the operation of the fuel cell to maintain the humidification of the MEA and fuel cells within a desired range to achieve a desired fuel cell performance.
摘要:
A strategy of controlling a state of hydration of a fuel cell(s) and actively managing operation of the fuel cell(s) to achieve a desired state of hydration. The control strategy monitors the state of hydration and a rate of change of the state of hydration which are used to control the operation of the fuel cell(s). A supervisory control strategy is implemented that alters the operating parameters of the fuel cell(s) based upon the state of hydration, the rate of change of the state of hydration, and a desired operational range for the state of hydration.
摘要:
A fuel cell system that includes an over-arching algorithm for providing a strategy that reduces relative humidity cycling of the cathode outlet gas between wet and dry operation to extend the useful life of the membrane. The algorithm receives sensor signals indicative of operating parameters of the fuel cell system. The algorithm maintains a cathode exhaust gas relative humidity in a wet operating mode if the operating parameters of the fuel cell system are able to sustain the cathode gas relative humidity above a first predetermined value, and maintains the cathode exhaust gas relative humidity in a dry operating mode if the operating parameters of the fuel cell system are able to sustain the cathode gas relative humidity below a second predetermined value.