A method for operating a fuel cell system is provided. The method includes controlling a provision of fuel to the fuel cell system operating in a steady-state mode. The catalyst sensor is operated by providing a portion of the fuel and anode exhaust generated by the system to the catalyst sensor. Further, a change in an outlet temperature of the catalyst sensor is detected. Thereafter, it is determined whether a reformation catalyst of the catalyst sensor is poisoned by contaminants in the fuel based on the detected change in the outlet temperature.

A method of detecting degradation of a membrane electrode assembly of a fuel cell is provided. In the method, it is possible to detect degradation (cross leakage) of the fuel cell. In the measurement step, the pressure drop value of the pressure of the fuel gas which decreases in the power generation state after discharging of the predetermined amount of the fuel gas, in each predetermined period of time is measured a plurality of times. Thereafter, in the determination step, it is determined that the membrane electrode assembly has been degraded in the case where the minimum pressure drop value, among a plurality of pressure measurement values, exceeds a threshold value.

System for recirculating hydrogen in a fuel cell including a tank having an inlet connectable to an outlet of the fuel cell and an outlet connectable to a line for feeding hydrogen to the fuel cell; the recirculation system includes a first check valve and a second check valve; the first check valve can be inserted between the outlet of the fuel cell and the inlet of the tank, for adjusting a flow from the fuel cell to the tank whilst the second check valve can be inserted between the outlet of the tank and the hydrogen feed line, for adjusting a flow of hydrogen from the tank to the feed line.

The present invention relates to a method for adjusting an operating mode of a fuel cell system (1) comprising: at least one fuel cell stack (2) having an anode portion (3) and a cathode portion (4); an anode supply line (5) for conveying fuel from a fuel source (6) to the anode portion (3); a fuel supply device (7) for supplying the fuel in the anode supply line (5) to the anode portion (3); an anode discharge line (8) for discharging anode exhaust gas from the anode portion (3) into the environment; and a purge unit (9) for purging the anode portion (3); said method comprising the steps of: determining a purge start time and/or a purge duration in which the anode portion (3) is intended to be purged by the purge unit (9); and shifting the fuel supply device (7) from a normal operation into a fuel-supply operation specific to the purge operation on the basis of the determined purge start time and/or purge duration, wherein the shifting into the fuel-supply operation specific to the purge operation is carried out temporally before and/or during the determined purge duration. The invention also relates to a fuel cell system (1), a computer program product (16) and a memory means having a computer program product (16) stored thereon for carrying out the method according to the invention.

A fuel cell system includes a fuel cell having a cathode and an anode configured to receive a portion of a hhydrocarbon feed and to output an anode exhaust stream comprising carbon dioxide, hydrogen, and water; and an electrolyzer cell having a cathode and an anode. The anode of the electrolyzer cell is configured to receive a first portion of the anode exhaust stream and another portion of the hydrocarbon feed, and to generate a hydrogen stream.

A fuel cell system includes an inlet pipe configured to guide a fuel gas injected from an injector to a fuel cell stack, and a gas liquid separator configured to perform gas liquid separation of a fuel exhaust gas discharged from the fuel cell stack. The gas liquid separator is directly coupled to a lower portion of the inlet pipe. A connection channel configured to connect the inside of the gas liquid separator and a channel in the inlet pipe together is formed in a part coupling the gas liquid separator and the inlet pipe together.

A method for controlling a carbon dioxide utilization in a fuel cell assembly includes: measuring a voltage across the fuel cell assembly; determining an estimated carbon dioxide utilization of the fuel cell assembly based on at least the measured voltage across the fuel cell assembly by determining an expected voltage of the fuel cell assembly based on at least a temperature of the fuel cell assembly, a current density across the fuel cell assembly, a fuel utilization of the fuel cell assembly, and a cathode oxygen utilization of the fuel cell assembly; determining the estimated carbon dioxide utilization based on a comparison between the measured voltage and the determined expected voltage; comparing the determined estimated carbon dioxide utilization to a predetermined threshold utilization; and upon determining that the determined estimated carbon dioxide utilization is higher than the predetermined threshold utilization, reducing the carbon utilization of the fuel cell assembly.

The embodiment relates to an energy conversion system having: a Solid Oxide Fuel Cell (SOFC) unit (A) having an anode and a cathode side, for receiving a fuel (1) and a steam of oxidant (4) and for converting a fraction of chemical power of the fuel (1) into electric power; a combustor unit (B) to receive unconverted fuel (5) and unconverted oxidant (6), configured for converting the unconverted fuel (5) and the unconverted oxidant (6) into product gas (10); an expander unit (C) to receive the product gas (10) and configured for expanding said product gas (10) into flue gas (12); a cooler unit (E) in thermal relationship with a heat sink (27) and configured for cooling said flue gas (12); a separator (F) for removing condensed species (15) from the cooled gas (14) exiting the cooler unit (E); and a first compression unit (K) for increasing the pressure of said oxidant (26, 4, 8) to a value suitable for the SOFC unit (A) and the combustor unit (B).

A fuel cell system includes a fuel cell stack, a fuel inlet conduit configured to provide a fuel to a fuel inlet of the fuel cell stack, an electrochemical pump separator containing an electrolyte, a cathode, and a carbon monoxide tolerant anode, a fuel exhaust conduit that operatively connects a fuel exhaust outlet of the fuel cell stack to an anode inlet of the electrochemical pump separator, and a product conduit which operatively connects a cathode outlet of the electrochemical pump separator to the fuel inlet conduit.

Disclosed are a method of controlling an operation of a fuel cell and a fuel cell operating system including an air compressor disposed on an air supply line and configured to compress an oxidation gas to be supplied to a fuel cell stack and supply the compressed air to a fuel cell inlet side, an air discharge line configured to discharge the oxidation gas from the fuel cell stack, a bypass line configured to branch off from the air discharge line through a valve, connected to the air supply line, and configured to resupply the discharged oxidation gas to the fuel cell inlet side, and a control unit configured to control a flow rate of the oxidation gas to be supplied to the fuel cell stack by controlling the valve on the bypass line depending on a cell ratio value which is a ratio of the fuel cells each being applied with a voltage lower than a first voltage among the fuel cells.