Abstract: The invention is a hydrogen passivation shut down system for a fuel cell power plant (10, 200). During shut down of the plant (10, 200), hydrogen fuel is permitted to transfer between an anode flow path (24, 24?) and a cathode flow path (38, 38?). A controlled-oxidant flow device (209) near an oxygen source (58?) permits a minimal amount of atmospheric oxygen to enter the power plant (200) during shut down to equalize pressure between ambient atmosphere and the flow paths (24?, 28?) and to keep limited atmospheric oxygen entering the power plant (200) through the device (209) as far as possible from fuel cell flow fields (28?, 42?). A non-leaking hydrogen inlet valve (202), a non-leaking cathode exhaust valve (208), and a combined oxidant and fuel exhaust line (206) also minimize penetration of oxygen into the shut down power plant (200).

Abstract: A fuel cell power plant (100) having a stack of fuel cells (102), each having an anode (104), a fuel reactant gas flow field plate (118), a cathode (106), an oxidant reactant gas flow field plate (120), and an electrolyte (101) between the anode and cathode. The stack has coolant channels (131), an air blower (144), air inlet (139a) and outlet (141a) valves, and a cathode recycle loop using either the primary air blower or a cathode recycle blower (135). A shutdown process includes recycling air through the cathodes with only one of an air inlet valve or air exit valve closed, while applying fresh fuel and recycling fuel through the anodes until oxygen is about 4% or less, or average cell voltage is about 0.2 or less, or for predetermined period of time.

Abstract: A fuel cell power plant (5) includes a stack (6) of fuel cells, each of which have an anode (9), a cathode (10), and a PEM (11) disposed between the anode and the cathode. A controller (17) recognizes an indication (67) of no load demand (68) by a load (59), to operate (45) an air recycle loop (44-46) utilizing the process air blower (35) and transfer the power output (57) of the stack from the load (59) to an auxiliary load (60), comprising a resistance which will consume a predetermined small amount of power in response to the current applied thereto, when the stack operates at a critical voltage above which fuel cell corrosion is unacceptable. Fuel and air will also be reduced (16, 40). The controller may cause increased cathode recycle when the critical voltage is reached and increased air when the voltage is a fraction of a volt below the critical voltage.

Abstract: A fuel cell power plant (100) having a stack of fuel cells (102), each having an anode (104), a fuel reactant gas flow field plate (118), a cathode (106), an oxidant reactant gas flow field plate (120), and an electrolyte (101) between the anode and cathode. The stack has coolant channels (131), an air blower (144), air inlet (139a) and outlet (141a) valves, and a cathode recycle loop using either the primary air blower or a cathode recycle blower (135). A shutdown process includes recycling air through the cathodes with only one of an air inlet valve or air exit valve closed, while applying fresh fuel and recycling fuel through the anodes until oxygen is about 4% or less, or average cell voltage is about 0.2 or less, or for predetermined period of time.

Abstract: A fuel cell includes a cathode having an air flow field. An anode includes an inlet and an outlet for providing unused fuel to a fuel recycling line. A pressure regulator is arranged upstream from an ejector and communicates with the air flow field for adjusting a fuel pressure at the motive inlet in response to an air pressure associated with the air flow field. The cathode and/or anode includes a porous water transport plate adjacent to the air flow field and/or fuel flow field respectively. A back pressure valve is arranged downstream from the air flow field for producing an air back pressure that generates a desired differential pressure across the water transport plate. The back pressure valve is controlled to achieve the desired differential pressure across the water transport plate so that the fuel cell maintains water balance.

Abstract: The invention is a hydrogen passivation shut down system for a fuel cell power plant (10, 200). During shut down of the plant (10, 200), hydrogen fuel is permitted to transfer between an anode flow path (24, 24?) and a cathode flow path (38, 38?). A controlled-oxidant flow device (209) near an oxygen source (58?) permits a minimal amount of atmospheric oxygen to enter the power plant (200) during shut down to equalize pressure between ambient atmosphere and the flow paths (24?, 28?) and to keep limited atmospheric oxygen entering the power plant (200) through the device (209) as far as possible from fuel cell flow fields (28?, 42?). A non-leaking hydrogen inlet valve (202), a non-leaking cathode exhaust valve (208), and a combined oxidant and fuel exhaust line (206) also minimize penetration of oxygen into the shut down power plant (200).

Abstract: The air blower (18) of a fuel cell power plant (9) is used to force water out of the coolant flow fields (27) of a fuel cell stack (10), a coolant pump (35) and a heat exchanger (40) through a valve (46) which is closed during normal operation. The water removal occurs as part of a shutdown procedure in which the fuel cell stack continues to operate so that it provides the power for the air pump and to assist in water removal (such as retaining low vapor pressure). The water flow to an accumulator (33) is blocked by a valve (29) during the shutdown procedure.

Abstract: The outflow of coolers or water transport plates of a fuel cell stack (15) is fed to the inlet of a gas/liquid separator (12), the liquid output of which is connected through a primary pump (11a) to a liquid accumulator (21). A secondary pump (44) connected to the liquid output (20) of the liquid accumulator is fed to the principal inlet (31) of an eductor (32), the secondary inlet being connected to the gas output of the gas/liquid separator. The outlet (37) of the eductor is fed through a conduit (38) to a point below liquid level in the liquid accumulator. Thus, failure of the secondary pump (44) will not cause cavitation of the primary pump (11a) through the eductor so that coolant will continue to flow through the fuel cell stack. A demineralizer (26) is fed through a pressure reducing orifice (25) from the outlet of the secondary pump.

Abstract: This invention relates to a new and distinct cultivar of strawberry plant named ‘DrisStrawEleven’. The new cultivar is primarily characterized by its medium-sized, conical-shaped fruit having a strong sweetness and medium acidity and moderate resistance to Strawberry Moftle Virus, is disclosed.