A carbon dioxide production system 10A includes: a fuel cell stack 16; a separation unit 20 that separates anode off-gas into a non-fuel gas including at least carbon dioxide and water and a regenerative fuel gas; a second heat exchanger 32 that separates water from the non-fuel gas; a water tank 42; and a carbon dioxide recovery tank 48 that recovers the carbon dioxide after the water has been separated.

A fuel cell system includes: a reformer which generates a reformed gas containing hydrogen by reacting hydrocarbon and moisture with each other; a fuel cell stack which generates electric energy through electrochemical reaction of the reformed gas and an oxidant; an ejector which, using steam as a drive fluid, sucks either a raw fuel containing the hydrocarbon or a recycled gas recovered from an anode exhaust gas, and supplies a resultant gas to the reformer; and a vaporizer which generates the steam by vaporizing water, wherein an operation temperature of the fuel cell stack is higher than a boiling point of water at an operation pressure, and the vaporizer generates the steam through heat exchange with the anode exhaust gas.

A fuel cell system including: a first fuel cell performing power generation using a fuel gas; a separation membrane separating at least one of carbon dioxide or water vapor from an anode off gas discharged from the first fuel cell; a second fuel cell disposed in the downstream of the separation membrane and performing power generation using the anode off gas, the anode off gas having at least one of carbon dioxide or water vapor separated therefrom; and a distribution channel disposed on a permeation side of the separation membrane and distributing any of the following: a raw material gas serving as the fuel gas to be reformed and used for the power generation of the first fuel cell, a cathode gas including oxygen to be used for the power generation of the first fuel cell, an anode off gas discharged from the second fuel cell, a cathode off gas discharged from the first fuel cell and to be supplied to the second fuel cell, or a cathode off gas discharged from the second fuel cell, in which at least one of permeability coefficient ratio α1 of the separation membrane or permeability coefficient ratio α2 of the separation membrane is 30 or higher.

An electrochemical module (EM) transfers a fluid across a membrane thereof using oxygen as a carrier gas. The EM has an anion exchange membrane (AEM) disposed between a first and second electrodes, each of which includes a catalyst. At an inlet side, the catalyst facilitates reaction of the fluid with carrier gas, such that an anion is formed. The anion is transported across the AEM in the presence of an electric field applied to the electrodes. At an outlet side, the catalyst facilitates dissociation of the anion back to the fluid and carrier gas. In some embodiments, the fluid comprises carbon dioxide, and the transporting by the EM is part of a heating/cooling cycle or a power generation cycle, or is used to capture carbon dioxide for storage or regeneration of stale air. In some embodiments, the fluid comprises water vapor, and the transporting by the EM dehumidifies air.

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.

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 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 fuel cell device (10) comprising a reformer (26) is disclosed, which is provided for reforming fuel (B) for electrochemical conversion in a fuel cell unit (12), and a fuel cell unit (12), which is provided to electrochemically convert reformed fuel (RB). It is proposed to arrange a heat exchanger (40) downstream of the reformer (26) and upstream of the fuel cell unit (12) in relation to a supply of reformed fuel (RB) to the fuel cell unit (12).

A flame-assisted fuel cell gas turbine hybrid system including a first combustor, a second combustor, and a flame-assisted solid oxide fuel cell configured to receive syngas from the first combustor, react the syngas with oxygen ions to yield carbon dioxide and water, and provide unreacted syngas to the second combustor. The first combustor is configured to receive heated compressed air from an aircraft engine compressor and the second combustor is configured to provide heated air to an aircraft engine gas turbine to generate mechanical power.