Abstract:
Die Erfindung betrifft ein Verfahren zum Betrieb eines Brennstoffzellensystems (1) mit mindestens einer Brennstoffzelle (2), wobei ein Massenstrom (10) die Brennstoffzelle (2) durchströmt. Erfindungsgemäß ist vorgesehen, dass das Verfahren einen ersten Schritt zur Erkennung eines Abweichens von einem zulässigen Betriebsbereich (B) enthält, wobei der erste Schritt folgende Einzelschritte umfasst: Definieren des zulässigen Betriebsbereich (B) dadurch, dass einem Massenstromwert ( m ) zulässige Druckdifferenzen (ΔP) aus einem ersten Druck (P 1 ) des Massenstroms (10) vor der Brennstoffzelle (2) und einem zweiten Druck (P 2 ) des Massenstroms (10) nach der Brennstoffzelle (2) innerhalb von Toleranzgrenzen (B', B") zugeordnet werden, Messen des ersten Drucks (P 1 ) vor einem Eintritt des Massenstroms (10) in die Brennstoffzelle (2) an einem Zeitpunkt, Messen des zweiten Drucks (P 2 ) nach einem Austritt des Massenstroms (10) aus der Brennstoffzelle (2) an dem Zeitpunkt, Schließen auf ein Abweichen von dem zulässigen Betriebbereich (B), wenn ein Betriebspunkt (A, A 1 , A 2 , A 3 , A 4 , A 5 ), der durch eine Zuordnung des Massenstromwertes ( m ) des, insbesondere zeitgleich, durchströmenden Massenstroms (10) zu einer gemessenen Druckdifferenz (ΔP) aus dem gemessenen ersten Druck (P 1 ) und dem gemessenen zweiten Druck (P 2 ) charakterisiert ist, außerhalb der Toleranzgrenzen (B', B") des zulässigen Betriebsbereichs (B) liegt, und dass das Verfahren einen zweiten Schritt enthält, bei dem aus dem Abweichen von dem zulässigen Betriebsbereich (B) eine Schlussfolgerung gezogen wird und das Brennstoffzellensystem (1) zu einer entsprechenden Reaktion veranlasst wird. Ferner ist die Erfindung auch auf ein Brennstoffzellensystem gemäß des Patentanspruchs 13 gerichtet.
Abstract:
The invention concerns fuel cell systems that achieve an increased level of operating safety. In this the operating safety of fuel cell systems with occurring system- and/or safety-critical conditions can be increased in a simple and economical manner. In a fuel cell system according to the invention there exists at least one supply for at least one oxidizable fluid, at least one supply for at least one oxidizing fluid, and at least one exhaust for at least one exhaust gas. With the use of at least one sensor a system- and/or safety-critical condition can be detected and by means of this at least one of the supply pipes for oxidizable fluid and/or oxidizing fluid and/or the exhaust pipe for exhaust gas can be completely or partially closed and/or opened by means of at least one closing device. Alone or additionally, a supply pipe for a non-, or hardly oxidizable fluid can be released and/or the electrical load can be altered or switched off.
Abstract:
The method for limiting the output voltage of a PEM fuel cell system operating in, or near, zero load conditions, in such a way as to minimize degradation of performance over time, comprises : supplying a hydrogen stream to the anode of said fuel cell; supplying an oxygen stream to the cathode of said fuel cell; monitoring an output voltage of the fuel cell; monitoring a hydrogen pressure in the fuel cell; monitoring an oxygen pressure in the fuel cell; limiting the hydrogen stream and the oxygen stream while actuating controllable recirculating pumps for the hydrogen and the oxygen in such a way as to bring and maintain the hydrogen and oxygen pressures below 1 bar absolute while maintaining said hydrogen pressure between 70 and 130 % of said oxygen pressure, so that the output voltage remains below.90 volts.
Abstract:
A method of starting operation of a fuel cell system (100) comprising a fuel cell stack (HO), the method comprising the steps of: i) opening an anode inlet valve (153) to allow fuel to enter an anode volume of the fuel cell stack (110); H) operating an air compressor (133) in fluid communication with a cathode air inlet (126) of the fuel cell stack (110) to allow air to enter a cathode volume of the fuel cell stack (110); iii) monitoring the temperature of the cathode inlet (126) and/or outlet (121); and iv) operating a water injection system to inject water into the cathode volume once the temperature of fluid passing through the cathode inlet and/or outlet exceeds a preset level, wherein a current drawn from the fuel cell stack (110) is limited to prevent a voltage measured across one or more cells in the fuel cell stack (110) from falling below a first voltage threshold.
Abstract:
Disclosed is a segmented modular solid oxide fuel cell device having a plurality of independently controllable electrical power producing segments disposed within a common thermal environment. Also disclosed are methods for selectively operating one or more segments of the disclosed segmented modular solid oxide fuel cell device. Also disclosed are methods for performing a maintenance process on one or more segments of a segmented modular fuel cell device during fuel cell operation.
Abstract:
An operation method at the time of load increase of fuel cell system (10) includes in this order a first step of determining a target power generation amount of the fuel cell module (12), a second step of increasing the flow rate of the oxygen-containing gas supplied to the fuel cell module (12), a third step of increasing the flow rate of the water supplied to the fuel cell module (12), a fourth step of increasing the flow rate of the fuel gas supplied to the fuel cell module (12), a fifth step of increasing the power generation amount of the fuel cell module (12), and a sixth step of detecting whether the power generation amount of the fuel cell module (12) reaches the target power generation amount or more.
Abstract:
A method of operating a fuel cell system (10) includes the steps of detecting whether supply of a raw fuel to a fuel cell module (12) is stopped or not, starting supply of water vapor to an electrode surface of an anode based on the temperature of a fuel cell stack (34) when stop of the supply of the raw fuel is detected, starting supply of reverse electrical current to an electrolyte electrode assembly in a direction opposite to electrical current flowing at the time of power generation based on the temperature of the fuel cell stack (34), stopping the supply of the reverse electrical current at least based on any of the temperature of the fuel cell stack (34) and the temperature of an evaporator (38), and stopping the supply of the water vapor at least based on any of the temperature of the fuel cell stack (34) and the temperature of the evaporator (38).