A fuel cell system includes a fuel feeder that supplies fuel, a fuel cell stack that generates power through an electrochemical reaction using air and a hydrogen-containing gas generated from the fuel, a temperature sensor that senses the temperature of the fuel cell stack, and a controller. The fuel cell stack has a membrane electrode assembly including an electrolyte membrane through which protons can pass, a cathode on one side of the electrolyte membrane, and an anode on the other side of the electrolyte membrane. The controller defines an upper limit of current output from the fuel cell stack on the basis of the temperature of the fuel cell stack and the supply of the fuel and keeps the current output from the fuel cell stack at or below the upper limit.

The invention relates to bio-electrochemical systems for the generation of methane from organic material and for reducing chemical oxygen demand and nitrogenous waste through denitrification. The invention further relates to an electrode for use in, and a system for, the adaptive control of bio-electrochemical systems as well as a fuel cell.

A valve device for controlling an air flow of a fuel cell stack includes: a housing connected to the fuel cell stack and including a plurality of manifolds formed therein; a disk rotatably provided in the housing to control the air flow of the fuel cell stack; and a central shaft provided at the center of the housing to rotate the disk.

A valve device for controlling an air flow of a fuel cell stack includes: a housing connected to the fuel cell stack and including a plurality of manifolds formed therein; a disk rotatably provided in the housing to control the air flow of the fuel cell stack; and a central shaft provided at the center of the housing to rotate the disk.

A system for controlling gas flow in a fuel cell circuit includes a fuel cell stack, a pressure sensor, and a valve to adjust a flow of gas through the fuel cell circuit. The system further includes an ECU designed to estimate pressure values of the gas at multiple locations in the fuel cell circuit based on the detected pressure of the gas and based on flow resistance values (including at the valve), the estimated pressure values including an estimated sensor pressure value at a location of the pressure sensor. The ECU is further designed to determine a pressure deviation between the detected pressure and the estimated sensor pressure value. The ECU is further designed to adjust the flow resistance value of the valve to determine a final flow resistance value of the valve that causes the pressure deviation to reach or drop below a threshold deviation amount.

A system for controlling gas flow in a fuel cell circuit includes a fuel cell stack, a pressure sensor, and a valve to adjust a flow of gas through the fuel cell circuit. The system further includes an ECU designed to estimate pressure values of the gas at multiple locations in the fuel cell circuit based on the detected pressure of the gas and based on flow resistance values (including at the valve), the estimated pressure values including an estimated sensor pressure value at a location of the pressure sensor. The ECU is further designed to determine a pressure deviation between the detected pressure and the estimated sensor pressure value. The ECU is further designed to adjust the flow resistance value of the valve to determine a final flow resistance value of the valve that causes the pressure deviation to reach or drop below a threshold deviation amount.

A reaction device comprising: a first flow path to which a fuel gas is supplied; a second flow path to which a gas containing oxygen is supplied; a hydrogen permeable membrane that separates the first flow path and the second flow path and allows hydrogen contained in the fuel gas supplied to the first flow path to permeate toward the second flow path; and a catalyst that is provided in the second flow path and promotes oxidation reaction between the oxygen and hydrogen passing through the hydrogen permeable membrane, wherein the hydrogen permeable membrane comprises a barium zirconium oxide membrane.

A fuel cell system is provided that includes a fuel cell with an assembly of multiple individual cells, each of which has an anode section, an electrolyte membrane, and a cathode section, an anode gas supply, which leads to an anode gas inlet and includes a fuel cell and a fuel metering device, a cathode gas supply, and a passive anode gas recirculation device, which connects an anode gas outlet to the recirculation gas inlet of a mixer arranged in the anode gas supply. The fuel cell system is started up after a standstill in that in a first phase, the fuel cell is activated while fuel is supplied from the fuel source, and the anode recirculation is suppressed without actively blocking the anode gas recirculation device, and in a second phase, anode gas is recirculated in addition to the supply of fuel from the fuel source.

A fuel cell device with a fuel tank which has a fuel supply line which is branched into fuel portion supply lines, having a plurality of fuel cell stacks which stacks each have, on the anode inlet side, a fuel connection which is respectively fluidically connected to one of the fuel portion supply lines. Exclusively one of the fuel cell stacks is connected on the anode outlet side to a fuel recirculation line. The flow guidance of the fuel recirculation line is selected in such a way that the fuel can be returned exclusively into the fuel cell stack connected to the fuel recirculation line. Furthermore, a method for operating the fuel cell device is provided.

The invention relates to a process for the thermal decomposition of ammonia. The process comprises passing ammonia through a conduit which contains an ammonia decomposition catalyst in a part thereof. At least a section of the part of the conduit which contains the catalyst is immersed in molten lead as heat transfer medium, which is at a temperature at which the catalyst is capable of catalyzing the decomposition of ammonia into hydrogen and nitrogen. A reactor for carrying out this process is also disclosed.