Abstract: A separator scrubber (58) and isolation loop (78) decontaminates a fuel reactant stream of a fuel cell (12). Water passes over surfaces of an ammonia dissolving means (61) within the scrubber (58) while the fuel reactant stream simultaneously passes over the surfaces to remove contaminants from the fuel reactant into the water. An accumulator (68) collects the separated contaminants and water, and an isolation loop pump (84) directs flow of the separated contaminant stream through the isolation loop (78). A heat exchanger (86) and an ion exchange bed (88) modify the heat of, and remove contaminants from, the separated contaminant stream, and the isolation loop (78) directs the decontaminated stream back onto the packed bed (62)-. Separating contaminants from the fuel reactant stream and then isolating and concentrating the separated contaminants within the ion exchange bed (88) minimizes cost and maintenance requirements.

Abstract: A liquid-gas separator assembly is used in separating gas bubbles from a liquid coolant which liquid coolant is used in a polymer electrolyte membrane (PEM) fuel cell power plant. The assembly includes a cylindrical housing containing a central tube which is surrounded by an annular chamber. The annular chamber is defined by the outer surface of the central tube and the inner surface of the cylindrical housing. An inlet line injects a stream of the coolant from the fuel cell stack area of the power plant into the bottom of the central tube in a tangential flow pattern so that the coolant and gas bubble mixture swirls upwardly through the central tube. The swirling flow pattern of the coolant and gas bubble mixture causes the gas bubbles to separate from the liquid coolant so that the gas in the mixture will migrate to the central portion of the swirl tube and the liquid component of the mixture will centrifugally migrate to the inner wall of the swirl tube.

Abstract: A separator scrubber (58) and isolation loop (78) decontaminates a fuel reactant stream of a fuel cell (12). Water passes over surfaces of an ammonia dissolving means (61) within the scrubber (58) while the fuel reactant stream simultaneously passes over the surfaces to remove contaminants from the fuel reactant into the water. An accumulator (68) collects the separated contaminants and water, and an isolation loop pump (84) directs flow of the separated contaminant stream through the isolation loop (78). A heat exchanger (86) and an ion exchange bed (88) modify the heat of, and remove contaminants from, the separated contaminant stream, and the isolation loop (78) directs the decontaminated stream back onto the packed bed (62)-. Separating contaminants from the fuel reactant stream and then isolating and concentrating the separated contaminants within the ion exchange bed (88) minimizes cost and maintenance requirements.

Abstract: A liquid-gas separator assembly is used in separating gas bubbles from a liquid coolant. The assembly includes a cylindrical housing containing a central tube which is surrounded by an annular chamber. The annular chamber is defined by the outer surface of the central tube and the inner surface of the cylindrical housing. An inlet line injects a stream of the coolant from the fuel cell stack area of the power plant into the bottom of the central tube in a tangential flow pattern so that the coolant and gas bubble mixture swirls upwardly through the central tube. The swirling flow pattern of the coolant and gas bubble mixture causes the gas bubbles to separate from the liquid coolant. The gaseous component of the separated mixture is then expelled from the housing through an outlet in the upper portion of the housing, and the coolant liquid descends through the annular chamber to the bottom of the housing.

Abstract: A liquid-gas separator assembly is used in separating gas bubbles from a liquid coolant which liquid coolant is used in a polymer electrolyte membrane (PEM) fuel cell power plant. The assembly includes a cylindrical housing containing a central tube which is surrounded by an annular chamber. The annular chamber is defined by the outer surface of the central tube and the inner surface of the cylindrical housing. An inlet line injects a stream of the coolant from the fuel cell stack area of the power plant into the bottom of the central tube in a tangential flow pattern so that the coolant and gas bubble mixture swirls upwardly through the central tube. The swirling flow pattern of the coolant and gas bubble mixture causes the gas bubbles to separate from the liquid coolant so that the gas in the mixture will migrate to the central portion of the swirl tube and the liquid component of the mixture will centrifugally migrate to the inner wall of the swirl tube.

Abstract: An arrangement is provided in a fuel cell power plant (10) for dispensing (58 74, 60, 64) a liquid medium, such as water (66), into a process oxidant (air) stream (53) that flows through one gas channel (42) in an energy recovery device (ERD) (32). An exhaust gas stream (48) containing heat and moisture from the fuel cell (12) flows through another channel (44) in the ERD. An enthalpy exchange barrier (46) separates the one and the other gas channels, but allows mass and/or heat transfer therebetween. The water is injected into the air stream (53) in a controlled (70, 74) amount, and perhaps temperature (78), in response to sensed parameters (80, 84, 90) of the power plant, including the process air stream, to adjust one or more conditions in the power plant. Controlling ERD dryness, providing a defrost capability for the ERD, and/or preventing excessive water accumulation in the system are several of the conditions controlled.

Abstract: An arrangement and process are provided for regulating the humidification or dew point of inlet air supplied (124, 224, 324, 424) to combustion-supported reaction means (20, 120) of a fuel processing system in a fuel cell power plant (110, 210, 310, 410). In addition to flowing exhaust gas(es) (28, 128) in heat and energy exchange relation with inlet air through a primary energy recovery device (ERD) (30) of the gas/gas type, a supplemental ERD (50) of the gas/liquid (water) type uses water temperature to passively condense moisture from a gas stream, either of inlet air or of exhaust gas, to regulate the dew point of the air supplied to the combustion-supported reaction means (20, 120). The supplemental ERD (50) may have a gas channel (134) and a water channel (132) separated by an enthalpy exchange barrier (136), and may be relatively upstream or downstream of the primary ERD (30) relative to the flow of inlet air through the latter to regulate dew point indirectly or directly, respectively.

Abstract: Method and apparatus are provided for removing contaminants from a hydrogen processor feed stream, as in a fuel cell power plant (110). Inlet oxidant (38), typically air, required by a catalytic hydrogen processor (34) in a fuel processor (14) for a fuel cell stack assembly (12) in the power plant (110), may contain contaminants such as SO2 and the like. A cleansing arrangement, which includes an accumulator/degasifier (142, 46) acting as a scrubber, and possibly also a water transfer device (118), receives the inlet oxidant and provides the desired cleansing of contaminants. Water in the water transfer device and in the accumulator/degasifier serves to dissolve the water-soluble contaminants and cleanse them from the oxidant stream. The cleansed oxidant stream (138?) is then delivered to the hydrogen processor and to the fuel cell assembly, with minimal inclusion of detrimental contaminants such as sulfur.

Abstract: A fuel cell power plant system includes the ability to operate an enthalpy recovery device even under cold conditions. A bypass arrangement allows for selectively bypassing one or more portions of the enthalpy recovery device under selected conditions. In one example, the enthalpy recovery device is completely bypassed under selected temperature conditions to allow the device to freeze and then later to be used under more favorable temperature conditions. In another example, the enthalpy recovery device is selectively bypassed during a system startup operation. One example includes a heater associated with the enthalpy recovery device. Another example includes preheating oxidant supplied to one portion of the enthalpy recovery device.

Abstract: Method and apparatus are provided for removing contaminants from a hydrogen processor feed stream, as in a fuel cell power plant (110). Inlet oxidant (38), typically air, required by a catalytic hydrogen processor (34) in a fuel processor (14) for a fuel cell stack assembly (12) in the power plant (110), may contain contaminants such as SO2 and the like. A cleansing arrangement, which includes an accumulator/degasifier (142, 46) acting as a scrubber, and possibly also a water transfer device (118), receives the inlet oxidant and provides the desired cleansing of contaminants. Water in the water transfer device and in the accumulator/degasifier serves to dissolve the water-soluble contaminants and cleanse them from the oxidant stream. The cleansed oxidant stream (138?) is then delivered to the hydrogen processor and to the fuel cell assembly, with minimal inclusion of detrimental contaminants such as sulfur.

Abstract: Water flow field inlet manifolds (33, 37) are disposed at the fuel cell stack (11) base. Water flow field outlet manifolds (34, 38) are located at the fuel cell stack top. Outlet and inlet manifolds are interconnected (41-43, 47, 49, 50) 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 (58) controls (56, 60, 62, 63) 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 (70) may be vertical. A hydrophobic region (80) provides gas leakage to ensure bubble pumping of water. An external heat exchanger (77) maximizes water density differential for convective flow.

Abstract: Water flow field inlet manifolds (33, 37) are disposed at the fuel cell stack (11) base. Water flow field outlet manifolds (34, 38) are located at the fuel cell stack top. Outlet and inlet manifolds are interconnected (41-43, 47, 49, 50) 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 (58) controls (56, 60, 62, 63) 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 (70) may be vertical. A hydrophobic region (80) provides gas leakage to ensure bubble pumping of water. An external heat exchanger (77) maximizes water density differential for convective flow.

Abstract: Method and apparatus are provided for removing contaminants from a hydrogen processor feed stream, as in a fuel cell power plant (110). Inlet oxidant (38), typically air, required by a catalytic hydrogen processor (34) in a fuel processor (14) for a fuel cell stack assembly (12) in the power plant (110), may contain contaminants such as SO2 and the like. A cleansing arrangement, which includes an accumulator/degasifier (142, 46) acting as a scrubber, and possibly also a water transfer device (118), receives the inlet oxidant and provides the desired cleansing of contaminants. Water in the water transfer device and in the accumulator/degasifier serves to dissolve the water-soluble contaminants and cleanse them from the oxidant stream. The cleansed oxidant stream (138′) is then delivered to the hydrogen processor and to the fuel cell assembly, with minimal inclusion of detrimental contaminants such as sulfur.

Abstract: A keep warm system for a fuel cell, power plant (10), typically of the PEM type, prevents freeze-sensitive portions of the power plant, such as the cell stack assembly (CSA) (12) and the water management system (28, 30), from freezing under extreme cold external temperatures, during extended storage (CSA shut-down) periods. Pre-stored and pressurized fuel, typically hydrogen (25), normally used to fuel the anode (16) of the CSA, is used as fuel for a catalytic oxidation reaction at a catalytic burner (66) to produce heated gas that convectively passes in heat exchange relation with the freeze sensitive portions (12, 28, 30) of the power plant (10). The convective flow of the heated gases induces the air flow to the burner (66), obviating the need for parasitic electrical loads.

Abstract: A proton exchange membrane (PEM) fuel cell includes fuel and oxidant flow field plates (26, 40) having fuel and oxidant channels (27, 28; 41, 44), and water channels, the ends (29, 48) of which that are adjacent to the corresponding reactant gas inlet manifold (34, 42) are dead ended, the other ends (31, 50) draining excess water into the corresponding reactant gas exhaust manifold (36, 45). Flow restrictors (39, 47) maintain reactant gas pressure above exit manifold pressure, and may comprise interdigitated channels (65, 66; 76, 78). Solid reactant gas flow field plates have small holes (85, 88) between reactant gas channels (27, 28; 41) and water drain channels (29, 30; 49, 50). In one embodiment, the fuel cells of a stack may be separated by either coolant plates (51) or solid plates (55) or both.

Abstract: A direct antifreeze cooled fuel cell is disclosed for producing electrical energy from reducing and process oxidant fluid streams that includes an electrolyte secured between an anode catalyst and a cathode catalyst; a porous anode substrate secured in direct fluid communication with and supporting the anode catalyst; a porous wetproofed cathode substrate secured in direct fluid communication with and supporting the cathode catalyst; a porous water transport or cooler plate secured in direct fluid communication with the porous cathode substrate; and, a direct antifreeze solution passing through the porous water transport plate. A preferred direct antifreeze solution passing through the porous water transport plate remains essentially within the water transport plate and does not poison the catalysts.

Abstract: A stack of plates (121) (such as fuel cells, electrochemical cells, or enthalpy exchange plates) is surrounded by a sleeve manifold (119) which is shaped to provide manifold chambers (34-39; 146-149; 151-153; 156-158; 161-163; 180-187), and including surfaces (142) for seals (143) to isolate the manifold chambers from each other. Sleeve manifolds (119a, 119b, 119c) may be formed of material of varying thickness, by machining, casting, or extrusion, or may be formed of material (119d) of uniform thickness by bending, casting or extrusion. Sleeve manifolds may be formed of metal, graphite, plastic or reinforced plastic.

Abstract: A stack of plates (121) (such as fuel cells, electrochemical cells, or enthalpy exchange plates) is surrounded by a sleeve manifold (119) which is shaped to provide manifold chambers (34-39; 146-149; 151-153; 156-158; 161-163; 180-187), and including surfaces (142) for seals (143) to isolate the manifold chambers from each other. Sleeve manifolds (119a, 119b, 119c) may be formed of material of varying thickness, by machining, casting, or extrusion, or may be formed of material (119d) of uniform thickness by bending, casting or extrusion. Sleeve manifolds may be formed of metal, graphite, plastic or reinforced plastic.

Abstract: A liquid-gas separator assembly is used in separating gas bubbles from a liquid coolant which liquid coolant is used in a polymer electrolyte membrane (PEM) fuel cell power plant. The assembly includes a cylindrical housing containing a central tube which is surrounded by an annular chamber. The annular chamber is defined by the outer surface of the central tube and the inner surface of the cylindrical housing. An inlet line injects a stream of the coolant from the fuel cell stack area of the power plant into the bottom of the central tube in a tangential flow pattern so that the coolant and gas bubble mixture swirls upwardly through the central tube. The swirling flow pattern of the coolant and gas bubble mixture causes the gas bubbles to separate from the liquid coolant so that the gas in the mixture will migrate to the central portion of the swirl tube and the liquid component of the mixture will centrifugally migrate to the inner wall of the swirl tube.

Abstract: A system and method are provided for managing water coolant in a PEM fuel cell system's (10) coolant circuit (14). Gas-liquid separating apparatus (26) serves to efficiently transport liquid coolant containing gases, and to separate gases from the liquid coolant. The liquid coolant having the gases removed therefrom is then circulated through the liquid circuit by means of a conventional pump (24). A vacuum pump (28), such as a liquid eductor (28′), associated with the gas-liquid separating apparatus (26), serves to efficiently transport gas-phase and/or gas-liquid phase, fluids and to assist in the degasification of the liquid coolant. The eductor discharges to a separator/accumulator (30; 30′) which further facilitates separation of gases from liquid coolant.