A fuel cell system comprising (i) at least one fuel cell stack (30) comprising at least one intermediate-temperature solid oxide fuel cell, and having an anode inlet (41) and a cathode inlet (61) and (ii) a reformer (70) for reforming a hydrocarbon fuel to a reformate, and a reformer heat exchanger (160); and defining: an anode inlet gas fluid flow path from a fuel source (90) to said reformer (70) to said fuel cell stack anode inlet (41); a cathode inlet gas fluid flow path from an oxidant inlet (140, 140′, 140″) through at least one cathode inlet gas heat exchanger (110, 150) to said reformer heat exchanger (160) to said fuel cell stack cathode inlet (61); wherein said at least one cathode inlet gas heat exchanger (110, 150) is arranged to heat relatively low temperature cathode inlet gas by transfer of heat from at least one of (i) an anode off-gas fluid flow path and (ii) a cathode off-gas fluid flow path; wherein said reformer heat exchanger is arranged for heating said anode inlet gas from said relatively high temperature cathode inlet gas to a temperature T.sub.3 at the anode inlet that is below a temperature T.sub.1 at the cathode inlet; and wherein oxidant flow control means (200) for controlled mixing of low temperature oxidant from the or each oxidant inlet (140, 140′, 140″) with high temperature cathode inlet gas to control a temperature T.sub.1 at the cathode inlet (61) relative to a temperature T.sub.3 at the anode inlet (41) and at a level higher than T.sub.3.

A fuel cell system comprising (i) at least one fuel cell stack (30) comprising at least one intermediate-temperature solid oxide fuel cell, and having an anode inlet (41) and a cathode inlet (61) and (ii) a reformer (70) for reforming a hydrocarbon fuel to a reformate, and a reformer heat exchanger (160); and defining: an anode inlet gas fluid flow path from a fuel source (90) to said reformer (70) to said fuel cell stack anode inlet (41); a cathode inlet gas fluid flow path from an oxidant inlet (140, 140′, 140″) through at least one cathode inlet gas heat exchanger (110, 150) to said reformer heat exchanger (160) to said fuel cell stack cathode inlet (61); wherein said at least one cathode inlet gas heat exchanger (110, 150) is arranged to heat relatively low temperature cathode inlet gas by transfer of heat from at least one of (i) an anode off-gas fluid flow path and (ii) a cathode off-gas fluid flow path; wherein said reformer heat exchanger is arranged for heating said anode inlet gas from said relatively high temperature cathode inlet gas to a temperature T.sub.3 at the anode inlet that is below a temperature T.sub.1 at the cathode inlet; and wherein oxidant flow control means (200) for controlled mixing of low temperature oxidant from the or each oxidant inlet (140, 140′, 140″) with high temperature cathode inlet gas to control a temperature T.sub.1 at the cathode inlet (61) relative to a temperature T.sub.3 at the anode inlet (41) and at a level higher than T.sub.3.

A fuel cell module includes: a cell stack in which fuel cells are stacked; and a stack temperature controller through which the oxidant gas before being supplied to the cell stack flows. The fuel cell module includes a warm-up burner that produces combustion gas for warming the cell stack. The warm-up burner is arranged outside a housing space in which the cell stack is housed. The stack temperature controller is arranged to face the cell stack with a predetermined gap therebetween so as to exchange heat with the cell stack. The stack temperature controller is located adjacent to a combustion gas passage through which the combustion gas generated by the warm-up burner flows so as to allow heat exchange between the oxidant gas flowing through the stack temperature controller and the combustion gas generated by the warm-up burner.

A fuel cell module includes: a cell stack in which fuel cells are stacked; and a stack temperature controller through which the oxidant gas before being supplied to the cell stack flows. The fuel cell module includes a warm-up burner that produces combustion gas for warming the cell stack. The warm-up burner is arranged outside a housing space in which the cell stack is housed. The stack temperature controller is arranged to face the cell stack with a predetermined gap therebetween so as to exchange heat with the cell stack. The stack temperature controller is located adjacent to a combustion gas passage through which the combustion gas generated by the warm-up burner flows so as to allow heat exchange between the oxidant gas flowing through the stack temperature controller and the combustion gas generated by the warm-up burner.

Aspects of methods and systems to reduce degradation of a fuel cell (110) during start-up and shut-down cycles are disclosed. An anode exhaust stream (201′) is periodically directed via fluid communication through an oxygen capture media (86). After shut-down of the fuel cell and before or during start-up said media (86) removes oxygen in the anode exhaust stream. Periodically, heating the oxygen capture media (86) is employed to purge the oxygen collected and regenerate the media.

A method of maintaining a thermal balance in a solid oxide reversible fuel cell system comprising a solid oxide reversible fuel cell, an air intake for providing air to the solid oxide reversible fuel cell, and a steam reformer fluidly coupled to the solid oxide fuel cell for providing fuel to the solid oxide reversible fuel cell. The method comprising operating the solid oxide reversible fuel cell system in a forward mode in which the steam former receives natural gas and produces hydrogen gas and carbon monoxide to be provided to the solid oxide reversible fuel cell, and operating the solid oxide reversible fuel cell system in a reverse mode in which the steam reformer receives hydrogen gas and carbon dioxide from the solid oxide reversible fuel cell and produces natural gas and water.

A method of maintaining a thermal balance in a solid oxide reversible fuel cell system comprising a solid oxide reversible fuel cell, an air intake for providing air to the solid oxide reversible fuel cell, and a steam reformer fluidly coupled to the solid oxide fuel cell for providing fuel to the solid oxide reversible fuel cell. The method comprising operating the solid oxide reversible fuel cell system in a forward mode in which the steam former receives natural gas and produces hydrogen gas and carbon monoxide to be provided to the solid oxide reversible fuel cell, and operating the solid oxide reversible fuel cell system in a reverse mode in which the steam reformer receives hydrogen gas and carbon dioxide from the solid oxide reversible fuel cell and produces natural gas and water.

A fuel cell system including a fuel cell stack comprising at least one fuel cell and having an anode inlet, a cathode inlet, an anode off-gas outlet, a cathode off-gas outlet, and defining separate flow paths for flow of anode inlet gas, cathode inlet gas, anode off-gas and cathode off-gas. The fuel cell system further comprises a reformer for reforming a fuel to a reformate, the reformer comprising a reformer inlet for anode inlet gas, a reformer outlet for exhausting anode inlet gas, and a reformer heat exchanger. There is also provided a a pre-heater for heating cathode inlet gas, the cathode inlet gas pre-heater comprising a pre-heater inlet for cathode inlet gas, a pre-heater outlet for exhausting cathode inlet gas, and a pre-heater heat exchanger, and a heat source for providing heat source gas.

A method of operating a fuel cell system includes the operating a fuel cell unit, the recovery at the outlet of the fuel cell unit of a carbon dioxide-rich anodic gas flow, the cooling of the anodic gas flow and the condensation of the water present in the anodic gas flow in order to form a dry anodic flow, the introduction of the dry anodic flow into a carbon dioxide capture unit in order to form a carbon dioxide gas flow and a carbon dioxide-depleted anodic flow, the recycling of at least portion of the carbon dioxide-depleted anodic flow into the fuel feed flow.

A method of operating a fuel cell system includes the operating a fuel cell unit, the recovery at the outlet of the fuel cell unit of a carbon dioxide-rich anodic gas flow, the cooling of the anodic gas flow and the condensation of the water present in the anodic gas flow in order to form a dry anodic flow, the introduction of the dry anodic flow into a carbon dioxide capture unit in order to form a carbon dioxide gas flow and a carbon dioxide-depleted anodic flow, the recycling of at least portion of the carbon dioxide-depleted anodic flow into the fuel feed flow.