JP2020056087A - Hydrogen generation system and operation method thereof - Google Patents

Abstract

To restore the hydrogen purification efficiency of a hydrogen generation system by removing carbon monoxide adsorbed to a catalyst of an anode when the hydrogen purification efficiency decreases.SOLUTION: A hydrogen generation system comprises: an electrochemical device 10 for generating hydrogen at a cathode 5C by comprising an electrolyte membrane-electrode conjugant 9, supplying hydrogen-containing gas to an anode 5A, and flowing an electric current between the anode 5A and the cathode 5C; gas supplying means 16 for supplying the hydrogen-containing gas to the anode 5A; a power supply 13 for flowing the electric current between the anode 5A and the cathode 5C; and a controller 15. The controller 15 increases the current value of the power supply 13 to 110A so that a hydrogen utilization rate becomes 110% when the hydrogen utilization rate is 90% and the hydrogen generation system 20 is operated so that the current value is kept 90A, and when the hydrogen purification efficiency decreases to 18 or lower.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hydrogen generation system that generates high-purity hydrogen gas from a hydrogen-containing gas using an electrochemical reaction, and a method of operating the same.

  BACKGROUND ART Conventionally, there is known an electrochemical device that generates high-purity hydrogen gas from a hydrogen-containing gas by using an electrolyte membrane-electrode assembly in which an electrolyte membrane that selectively transports hydrogen ions is disposed between an anode and a cathode. Have been.

An anode of such an electrochemical device is supplied with a hydrogen-containing gas containing impurities, which is humidified so as to have a high dew point, and a current flows from the anode to the cathode via the electrolyte membrane. Then, an oxidation reaction occurs in which hydrogen dissociates into hydrogen ions (H ⁺ ) and electrons as shown in (Chem. 1). At the cathode, hydrogen ions (H ⁺ ) and electrons shown in (Chem. ² ) combine to form hydrogen. The resulting reduction reaction takes place.

（化１）と（化２）に示す電気化学反応により、アノードに供給された水素含有ガスから、カソードにおいて水素ガスが生成される。このとき、水素含有ガス中の水素のみがアノード側からカソード側へ移動するため、高純度の水素ガスを得ることができる。

By the electrochemical reaction shown in (Chemical Formula 1) and (Chemical Formula 2), hydrogen gas is generated at the cathode from the hydrogen-containing gas supplied to the anode. At this time, only hydrogen in the hydrogen-containing gas moves from the anode side to the cathode side, so that high-purity hydrogen gas can be obtained.

  The hydrogen-containing gas supplied to the anode of the electrochemical device is supplied, for example, by a fuel processor to convert a hydrocarbon-based fuel such as 13A gas or propane gas into steam reforming, partial oxidation reforming, or autothermal reforming. It is generated by quality.

  The hydrogen-containing gas obtained by using such a reforming reaction contains impurities such as carbon monoxide and carbon dioxide. It is known that carbon monoxide poisons the catalyst of the anode of the electrochemical device and lowers the catalytic performance (for example, see Patent Document 1).

  FIG. 9 is a schematic diagram of a conventional electrochemical device disclosed in Patent Document 1. As shown in FIG. 9, the conventional electrochemical device 200 includes an electrolyte membrane-electrode assembly, an anode separator 101A, a cathode separator 101C, an anode end plate 108A, a cathode end plate 108C, a voltage application unit 113, It has.

  The electrolyte membrane-electrode assembly has an anode catalyst layer 103A disposed on one main surface of the electrolyte membrane 104, a cathode catalyst layer 103C disposed on the other main surface of the electrolyte membrane 104, and an electrolyte membrane 104 on the anode catalyst layer 103A. The anode gas diffusion layer 102A is provided on a surface that does not face the cathode gas diffusion layer 102C, and the cathode gas diffusion layer 102C is provided on a surface of the cathode catalyst layer 103C that does not face the electrolyte membrane 104.

  The anode separator 101A has a groove-shaped anode gas flow path 114A formed on a surface that contacts the anode gas diffusion layer 102A. The cathode separator 101C has a groove-shaped cathode gas flow channel 114C formed on a surface that contacts the cathode gas diffusion layer 102C.

  Then, an electrolyte membrane-electrode assembly is arranged between the anode separator 101A and the cathode separator 101C.

  The anode end plate 108A is arranged on the surface of the anode separator 101A opposite to the surface on which the anode gas flow paths 114A are formed.

  An anode inlet pipe for supplying a hydrogen-containing gas to the anode gas flow path 114A is connected to a surface of the anode end plate 108A opposite to the surface facing the anode separator 101A. The anode end plate 108A makes the anode gas flow passage 114A communicate with the anode inlet pipe.

  The cathode end plate 108C is arranged on the surface of the cathode separator 101C opposite to the surface on which the cathode gas flow channel 114C is formed.

  A cathode outlet pipe for discharging hydrogen gas from the cathode gas flow channel 114C is connected to a surface of the cathode end plate 108C opposite to a surface facing the cathode separator 101C. The cathode end plate 108C makes the cathode gas flow path 114C communicate with the cathode outlet pipe.

  The voltage application unit 113 is a DC power supply having a positive electrode terminal and a negative electrode terminal. The positive electrode terminal of the voltage application unit 113 is connected to the anode separator 101A, and the negative electrode terminal of the voltage application unit 113 is connected to the cathode separator 101C. Connected.

  Then, the voltage applying unit 113 is provided between the anode separator 101A and the cathode separator 101C, from the anode separator 101A, to the anode gas diffusion layer 102A, the anode catalyst layer 103A, the electrolyte membrane 104, the cathode catalyst layer 103C, and the cathode gas diffusion layer 102C. Is passed in this order, and a current flowing through the cathode separator 101C is passed.

JP-A-2017-145187

  However, in the conventional configuration, the catalyst of the anode catalyst layer 103A is poisoned by impurities such as carbon monoxide contained in the hydrogen-containing gas supplied to the anode catalyst layer 103A, and the active site of the catalyst of the anode catalyst layer 103A is reduced. There was a problem that the reduction in hydrogen purification efficiency would be reduced.

  Here, the hydrogen purification efficiency is the ratio of the energy of the generated hydrogen to the electric energy input to the electrochemical device.

  The present invention solves the conventional problems, and removes poisonous substances adsorbed on the catalyst of the anode catalyst layer when the hydrogen purification efficiency of the electrochemical device decreases, thereby reducing the hydrogen purification efficiency of the electrochemical device. It is an object of the present invention to provide a hydrogen generation system capable of recovering a reduced amount and an operation method thereof.

  In order to solve the conventional problems, the hydrogen generation system of the present invention comprises an electrolyte membrane, an anode disposed on one main surface of the electrolyte membrane, and a cathode disposed on the other main surface of the electrolyte membrane. An electrochemical device that constitutes an electrode assembly, supplies a hydrogen-containing gas to the anode, and flows a current in a predetermined direction between the anode and the cathode to generate hydrogen at the cathode, and a gas that supplies the hydrogen-containing gas. A supply means, and a power supply for causing a current to flow between the anode and the cathode of the electrochemical device, wherein the amount of hydrogen generated at the cathode by the current is divided by the amount of hydrogen supplied to the anode and multiplied by 100 When the hydrogen generation system is operating, the electric energy supplied to the power supply is controlled so that the fuel utilization rate indicating that the fuel utilization is less than 100% and the current value of the current from the power supply is constant. Either the case where the hydrogen purification efficiency indicating the ratio of the hydrogen energy obtained from the cathode falls below the threshold value or the case where the voltage between the anode and the cathode rises above the threshold value, or the fuel utilization rate becomes 100%. %, The voltage between the anode and the cathode is constant, so that when the current value of the power supply decreases below the threshold value and when the hydrogen discharged from the cathode is At least when the flow rate is reduced below the threshold value or when the flow rate of the hydrogen-containing off-gas discharged from the anode is increased above the threshold value, at least the power supply current value is set so that the fuel utilization exceeds 100%. Either increasing the flow rate or decreasing the flow rate of the hydrogen-containing gas supplied from the gas supply means is performed.

  In this configuration, when the catalyst of the anode catalyst layer is poisoned by impurities such as carbon monoxide and a phenomenon such as a reduction in hydrogen purification efficiency below a threshold occurs, a hydrogen gas having a fuel utilization rate exceeding 100% is generated. When the starvation operation is performed, in addition to the electrochemical reaction shown in (Chem. 1), the electrochemical reactions shown in (Chem. 3), (Chem. 4) and (Chem. 5) occur at the anode.

ここで、燃料利用率が１００％を超える水素ガス欠乏運転とは、電気化学デバイスのアノードとカソードとの間に流す電流によりカソードで生成される水素量に対して、アノードに供給する水素含有ガス中の水素量が少ない状態で運転することである。

Here, the hydrogen gas deficient operation in which the fuel utilization exceeds 100% refers to the hydrogen-containing gas supplied to the anode with respect to the amount of hydrogen generated at the cathode by the current flowing between the anode and the cathode of the electrochemical device. It is to operate in a state where the amount of hydrogen is small.

  In such a hydrogen gas deficient operation, the amount of hydrogen ions becomes insufficient with only the hydrogen ions produced from hydrogen by the electrochemical reaction shown in (Chemical Formula 1). Therefore, in addition to the electrochemical reaction shown in (Chemical Formula 1), In order to produce the shortage of hydrogen ions, the electrochemical reactions shown in (Chem. 3), (Chem. 4) and (Chem. 5) occur at the anode.

Further, when the electrochemical reactions shown in (Chem. 3), (Chem. 4) and (Chem. 5) occur at the anode,
When the poisoning substance adsorbed on the active site of the catalyst in the anode catalyst layer is a poisoning substance that can be removed by oxidation, the poisoning substance can be removed.

  As described above, since the active site of the catalyst in the anode catalyst layer, which has been reduced by the adsorption of the poisonous substance, recovers, the decrease in the hydrogen purification efficiency of the electrochemical device can be recovered.

  ADVANTAGE OF THE INVENTION The hydrogen generation system of this invention and its operating method can remove the poisoning substance which can be oxidized and removed, such as carbon monoxide adsorbed by the catalyst of the anode catalyst layer. As a result, even if the poisoning substance is adsorbed on the catalyst of the anode catalyst layer and the active site of the catalyst on the anode catalyst layer is reduced, the poisoning substance adsorbed on the catalyst on the anode catalyst layer is removed. Since the active site of the catalyst recovers and returns to its original state, the decrease in the hydrogen purification efficiency of the electrochemical device can be recovered.

  Further, by recovering the hydrogen purification efficiency, electric energy used for the hydrogen generation system can be reduced, so that a hydrogen generation system with high energy saving can be provided.

Schematic diagram of the hydrogen generation system according to Embodiments 1 to 3 of the present invention Flow chart showing a flow of processing executed by the controller in the hydrogen generation system according to Embodiment 1 of the present invention. Flowchart showing the flow of processing executed by the controller in the hydrogen generation system according to Embodiment 2 of the present invention. Flow chart showing a flow of processing executed by a controller in the hydrogen generation system according to Embodiment 3 of the present invention. Schematic diagram of a hydrogen generation system in a hydrogen generation system according to Embodiment 4 of the present invention. Flow chart showing a flow of a process executed by a controller in the hydrogen generation system according to Embodiment 4 of the present invention. Schematic diagram of a hydrogen generation system in a hydrogen generation system according to Embodiment 5 of the present invention. Flow chart showing a flow of a process executed by a controller in the hydrogen generation system according to Embodiment 5 of the present invention. Schematic diagram of a conventional electrochemical device

  In the first invention, an electrolyte membrane-electrode assembly is constituted by an electrolyte membrane and an anode arranged on one main surface of the electrolyte membrane and a cathode arranged on the other main surface of the electrolyte membrane, and the anode contains hydrogen. A gas is supplied, and an electric current in a predetermined direction is caused to flow between the anode and the cathode, so that an electrochemical device that generates hydrogen at the cathode, a gas supply unit that supplies a hydrogen-containing gas, and a gas supply unit between the anode and the cathode A hydrogen generation system comprising a power supply for flowing an electric current and a controller, wherein the controller divides the amount of hydrogen generated at the cathode by the current by the amount of hydrogen supplied to the anode and multiplies the ratio by 100. When the hydrogen generation system is operating, the cathode is not used for the electric energy supplied to the power supply so that the indicated fuel utilization is less than 100% and the current value of the current from the power supply is constant. When the hydrogen purification efficiency indicating the ratio of the obtained hydrogen energy falls below the threshold, at least the current value of the power supply is increased or the hydrogen-containing gas supplied from the gas supply means is increased so that the fuel utilization exceeds 100%. The method is characterized in that one of the steps of reducing the flow rate is performed.

With this configuration, the catalyst of the anode catalyst layer is poisoned by impurities such as carbon monoxide,
When the hydrogen purification efficiency falls below the threshold value, the fuel gas is operated in a hydrogen gas deficient state in which the fuel utilization rate exceeds 100%. At the same time as the chemical reaction occurs, the poisoning substances adsorbed on the catalyst in the anode catalyst layer are oxidized and removed, so the active site of the catalyst in the anode catalyst layer is restored and the decrease in the hydrogen purification efficiency of the electrochemical device is recovered. Can be done.

  According to a second invention, an electrolyte membrane-electrode assembly is constituted by an electrolyte membrane and an anode arranged on one main surface of the electrolyte membrane and a cathode arranged on the other main surface of the electrolyte membrane, and the anode contains hydrogen. A gas is supplied, and an electric current in a predetermined direction is caused to flow between the anode and the cathode, so that an electrochemical device that generates hydrogen at the cathode, a gas supply unit that supplies a hydrogen-containing gas, and a gas supply unit between the anode and the cathode A hydrogen generation system including a power supply for flowing a current, a measuring device for measuring a voltage between an anode and a cathode, and a controller, wherein the controller determines an amount of hydrogen generated at the cathode by the current. When the hydrogen generation system is operated such that the fuel utilization rate, which is a ratio obtained by dividing by the amount of hydrogen supplied to the anode and multiplied by 100, is less than 100% and the current value of the current from the power supply is constant. When the voltage between the anode and the cathode measured by the measuring device rises above the threshold, at least the current value of the power supply is increased or supplied from the gas supply means so that the fuel utilization exceeds 100%. It is characterized in that either one of reducing the flow rate of the hydrogen-containing gas is performed.

  With this configuration, when the electrochemical device is operated at a constant current, the voltage between the anode and the cathode is measured by a measuring device, and when the voltage rises above a threshold, the fuel utilization exceeds 100%. Since the hydrogen gas deficient operation is performed, the poisoning substances adsorbed on the catalyst of the anode catalyst layer can be oxidized and removed by the hydrogen gas deficient operation. Therefore, the active site of the catalyst in the anode catalyst layer is recovered, and the decrease in the hydrogen purification efficiency of the electrochemical device can be recovered.

  According to a third invention, an electrolyte membrane-electrode assembly is constituted by an electrolyte membrane and an anode arranged on one main surface of the electrolyte membrane and a cathode arranged on the other main surface of the electrolyte membrane, and the anode contains hydrogen. A gas is supplied, and an electric current in a predetermined direction is caused to flow between the anode and the cathode, so that an electrochemical device that generates hydrogen at the cathode, a gas supply unit that supplies a hydrogen-containing gas, and a gas supply unit between the anode and the cathode A hydrogen generation system comprising a power supply for flowing an electric current and a controller, wherein the controller divides the amount of hydrogen generated at the cathode by the current by the amount of hydrogen supplied to the anode and multiplies the ratio by 100. When the current value of the power supply becomes smaller than the threshold value when the hydrogen generation system is operated so that the indicated fuel utilization is less than 100% and the voltage between the anode and the cathode is constant. In addition, at least one of increasing the current value of the power supply or decreasing the flow rate of the hydrogen-containing gas supplied from the gas supply means is performed so that the fuel utilization exceeds 100%. Things.

  With this configuration, when the electrochemical device is operated at a constant voltage, the current value of the power supply is detected, and when the current value becomes smaller than the threshold, the hydrogen gas deficient operation in which the fuel utilization exceeds 100% is performed. The poisoning substance adsorbed on the catalyst of the anode catalyst layer can be oxidized and removed by the hydrogen gas deficient operation. Therefore, the active site of the catalyst in the anode catalyst layer is recovered, and the decrease in the hydrogen purification efficiency of the electrochemical device can be recovered.

In a fourth aspect, an electrolyte membrane-electrode assembly is constituted by an electrolyte membrane and an anode disposed on one main surface of the electrolyte membrane and a cathode disposed on the other main surface of the electrolyte membrane, and the anode contains hydrogen. A gas is supplied, and an electric current in a predetermined direction is caused to flow between the anode and the cathode, so that an electrochemical device that generates hydrogen at the cathode, a gas supply unit that supplies a hydrogen-containing gas, and a gas supply unit between the anode and the cathode A hydrogen generation system comprising: a power supply for flowing an electric current; a first flow meter for measuring an amount of hydrogen discharged from a cathode; and a controller, the controller comprising: an amount of hydrogen generated at the cathode by the electric current Is divided by the amount of hydrogen supplied to the anode and multiplied by 100 to operate the hydrogen generation system so that the fuel utilization is less than 100% and the voltage between the anode and the cathode is constant. When the flow rate of hydrogen measured by the first flow meter decreases below the threshold value, at least the current value of the power supply is increased or supplied from the gas supply means so that the fuel utilization exceeds 100%. It is characterized in that either one of reducing the flow rate of the hydrogen-containing gas is performed.

  With this configuration, when the electrochemical device is operated at a constant voltage, the amount of hydrogen generated at the cathode is measured by the first flow meter that measures the amount of hydrogen discharged from the cathode, and the amount of hydrogen is smaller than the threshold. Since the hydrogen gas deficient operation in which the fuel utilization rate exceeds 100% is performed when the fuel gas decreases, the poisoning substances adsorbed on the catalyst of the anode catalyst layer can be oxidized and removed by the hydrogen gas deficient operation. Therefore, the active site of the catalyst in the anode catalyst layer is recovered, and the decrease in the hydrogen purification efficiency of the electrochemical device can be recovered.

  In a fifth aspect, an electrolyte membrane-electrode assembly is constituted by an electrolyte membrane and an anode arranged on one main surface of the electrolyte membrane and a cathode arranged on the other main surface of the electrolyte membrane, and the anode contains hydrogen. A gas is supplied, and an electric current in a predetermined direction is caused to flow between the anode and the cathode, so that an electrochemical device that generates hydrogen at the cathode, a gas supply unit that supplies a hydrogen-containing gas, and a gas supply unit between the anode and the cathode A hydrogen generation system comprising: a power supply for flowing a current; a second flow meter for measuring a flow rate of a hydrogen-containing off-gas discharged from an anode; and a controller, wherein the controller is configured to control a cathode at a cathode by the current. The amount of hydrogen generated is divided by the amount of hydrogen supplied to the anode and multiplied by 100, so that the fuel utilization is less than 100% and the water between the anode and the cathode is constant. If the flow rate of the hydrogen-containing off-gas measured by the second flow meter increases above the threshold value during operation of the generation system, at least the current value of the power supply is increased so that the fuel utilization exceeds 100%. Or reducing the flow rate of the hydrogen-containing gas supplied from the gas supply means.

  With this configuration, when the electrochemical device is operated at a constant voltage, the flow rate of the hydrogen-containing off-gas discharged from the anode is measured by the second flow meter, and when the flow rate increases to a threshold or more, the fuel utilization rate increases. Since the hydrogen gas deficient operation exceeding 100% is performed, the poisoning substance adsorbed on the catalyst of the anode catalyst layer can be oxidized and removed by the hydrogen gas deficient operation. Therefore, the active site of the catalyst in the anode catalyst layer is recovered, and the decrease in the hydrogen purification efficiency of the electrochemical device can be recovered.

In a sixth aspect, an electrolyte membrane-electrode assembly is constituted by an electrolyte membrane and an anode arranged on one main surface of the electrolyte membrane and a cathode arranged on the other main surface of the electrolyte membrane, and the anode contains hydrogen. An electrochemical device that generates hydrogen at the cathode by supplying a gas and flowing a current in a predetermined direction between the anode and the cathode, a gas supply unit that supplies a hydrogen-containing gas, and an anode and a cathode of the electrochemical device. And a power supply for causing a current to flow between the hydrogen supply system and the power supply, wherein the ratio is obtained by dividing the amount of hydrogen generated at the cathode by the current by the amount of hydrogen supplied to the anode and multiplying by 100. When the hydrogen generation system is operated, the electric energy supplied to the power source is controlled so that the fuel utilization is less than 100% and the current value of the current from the power source is constant. Either the case where the hydrogen purification efficiency indicating the ratio of the hydrogen energy obtained from the battery drops below the threshold value or the case where the voltage between the anode and the cathode rises above the threshold value, or the fuel utilization rate becomes 100%. %, The voltage between the anode and the cathode is constant, so that when the current value of the power supply decreases below the threshold value and when the hydrogen discharged from the cathode is At least when the flow rate decreases below the threshold value or when the flow rate of the hydrogen-containing off-gas discharged from the anode increases above the threshold value, at least the current value of the power supply so that the fuel utilization exceeds 100%. Or increasing the flow rate of the hydrogen-containing gas supplied from the gas supply means.

  According to this operation method, when the catalyst of the anode catalyst layer is poisoned by impurities such as carbon monoxide, and a phenomenon such as a reduction in hydrogen purification efficiency lowers below a threshold occurs, the fuel utilization rate exceeds 100%. Since the gas deficient operation is performed, the electrochemical reaction shown in (Chem. 3), (Chem. 4) and (Chem. 5) occurs by the hydrogen deficient operation, and at the same time, the poisoning substance adsorbed on the catalyst of the anode catalyst layer is removed. Since it is oxidized and removed, the active site of the catalyst in the anode catalyst layer is restored. Therefore, it is possible to provide an operation method for recovering a decrease in the hydrogen purification efficiency of the electrochemical device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a schematic diagram of a hydrogen generation system according to Embodiment 1 of the present invention. FIG. 2 is a flowchart showing a flow of processing executed by the controller in the hydrogen generation system according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the hydrogen generation system 20 according to the first embodiment includes an electrochemical device 10, a power supply 13, a controller 15, a gas supply unit 16, and a measuring device 17.

  The electrochemical device 10 has a configuration in which an electrolyte membrane-electrode assembly 9 in which an electrolyte membrane 4 is sandwiched between an anode 5A and a cathode 5C is sandwiched between an anode separator 1A and a cathode separator 1C.

  The anode 5A includes an anode catalyst layer 3A and an anode gas diffusion layer 2A, and the cathode 5C includes a cathode catalyst layer 3C and a cathode gas diffusion layer 2C. The electrolyte membrane 4 is disposed between the anode 5A and the cathode 5C.

  The electrolyte membrane-electrode assembly 9 has an anode catalyst layer 3A and an anode gas diffusion layer 2A laminated on one main surface of the electrolyte membrane 4, and a cathode catalyst layer 3C and a cathode catalyst on the other main surface of the electrolyte membrane 4. The gas diffusion layer 2C and the gas diffusion layer 2C are stacked.

  The anode catalyst layer 3A is disposed on one main surface of the electrolyte membrane 4. Cathode catalyst layer 3C is arranged on the other main surface of electrolyte membrane 4. The anode gas diffusion layer 2A is arranged on a surface of the anode catalyst layer 3A that does not face the electrolyte membrane 4. The cathode gas diffusion layer 2C is disposed on a surface of the cathode catalyst layer 3C that does not face the electrolyte membrane 4.

  Here, a polymer electrolyte membrane of a perfluorocarbon sulfonic acid group having a sulfonic acid group is used as the electrolyte membrane 4. As the anode catalyst layer 3A and the cathode catalyst layer 3C, those formed by coating and forming carbon particles carrying platinum are used. Further, carbon felt is used for the anode gas diffusion layer 2A and the cathode gas diffusion layer 2C.

  The anode separator 1A and the cathode separator 1C are made of compressed carbon which is a conductive member having no gas permeability.

  The anode separator 1A is provided with an anode-side inlet 11A, an anode-side outlet 12A, and an anode gas flow path 14A.

The anode gas flow path 14A is formed in a groove shape on the surface of the anode separator 1A that contacts the anode gas diffusion layer 2A (anode 5A), and the upstream end communicates with the anode inlet 11A and the downstream end communicates with the anode outlet 12A. ing.

  The anode-side inlet 11A is a hydrogen-containing gas supply passage for supplying a hydrogen-containing gas to the anode 5A via the anode gas flow path 14A. The anode-side outlet 12A discharges the hydrogen-containing gas remaining on the anode 5A without passing through the cathode 5C (the hydrogen-containing gas not used for hydrogen generation at the cathode 5C) from the anode 5A (anode gas flow path 14A). For discharging hydrogen-containing gas.

  The cathode separator 1C is provided with a cathode-side outlet 12C and a cathode gas flow path 14C.

  The cathode gas flow path 14C is formed in a groove shape on a surface of the cathode separator 1C that contacts the cathode gas diffusion layer 2C (cathode 5C), and has a downstream end communicating with the cathode-side outlet 12C.

  The cathode-side outlet 12C is used for discharging a hydrogen-containing gas (hydrogen gas generated by combining hydrogen ions and electrons at the cathode 5C) permeated to the cathode 5C from the cathode 5C (cathode gas passage 14C). It is a passage.

  The power supply 13 is a DC power supply that allows a current in a predetermined direction to flow between the anode 5A and the cathode 5C. Here, the current in the predetermined direction is a current flowing from the anode 5A of the electrochemical device 10 to the cathode 5C via the electrolyte membrane 4. The positive terminal of the power supply 13 is connected to the anode separator 1A, and the negative terminal of the power supply 13 is connected to the cathode separator 1C.

  Then, the power supply 13 causes a current to flow through the anode separator 1A, the electrolyte membrane 4, and the cathode 5C from the anode separator 1A to the cathode separator 1C in this order between the anode separator 1A and the cathode separator 1C.

  The gas supply means 16 supplies the humidified hydrogen-containing gas to the electrochemical device 10 from the anode-side inlet 11A. The gas supply unit 16 is configured by a fuel reformer that generates and supplies a hydrogen-containing gas from a city gas using a reforming reaction.

  The measuring device 17 measures a voltage value between the anode 5A and the cathode 5C of the electrochemical device 10.

  The controller 15 is connected to the power supply 13, the gas supply unit 16, and the measuring device 17, obtains a voltage value between the anode 5 </ b> A and the cathode 5 </ b> C from the measuring device 17, and supplies the voltage value to the electrochemical device 10 from the gas supplying unit 16. The supply amount of the hydrogen-containing gas to be supplied and the current value flowing from the power supply 13 to the electrochemical device 10 are controlled.

  The gas supply unit 16 is configured to be able to supply the hydrogen-containing gas at the supply amount of the hydrogen-containing gas specified by the controller 15 to the electrochemical device 10, and the power supply 13 controls the current value of the current value specified by the controller 15. It is configured such that a current can flow from the anode 5A of the electrochemical device 10 to the cathode 5C via the electrolyte membrane 4.

  The electrochemical device 10 is provided with a temperature controller (not shown) for adjusting the temperature, and the temperature controller uses a heat exchanger or a rubber heater for keeping the set temperature constant.

  The operation and operation of the hydrogen generation system 20 according to the present embodiment configured as described above will be described with reference to FIGS.

  First, in S1, a hydrogen-containing gas is supplied from the gas supply means 16 to the anode 5A via the anode-side inlet 11A of the electrochemical device 10.

  The hydrogen-containing gas supplied by the gas supply means 16 has a gas temperature of 85 ° C. and a relative humidity of 90%. The hydrogen-containing gas supplied by the gas supply means 16 has a content ratio of carbon monoxide of 0.002%, a content ratio of carbon dioxide of 20%, and a content ratio of hydrogen of 79.998%.

  Next, in S2, a current in the direction of flowing from the anode 5A to the cathode 5C via the electrolyte membrane 4 to the cathode 5C with a current value of 90A is supplied between the anode 5A and the cathode 5C of the electrochemical device 10 by the power source 13, The supply amount of the hydrogen-containing gas from the gas supply means 16 to the electrochemical device 10 is adjusted so that the utilization rate becomes 90%.

  In S2, even after the supply rate of the hydrogen-containing gas from the gas supply means 16 is adjusted so that the fuel utilization rate becomes 90%, the hydrogen generation operation is performed at a constant current so that the current value of 90A is maintained.

  By supplying a current from the anode 5A to the cathode 5C via the electrolyte membrane 4 while the hydrogen-containing gas is being supplied to the anode 5A, the hydrogen contained in the hydrogen-containing gas is dissociated into hydrogen ions and electrons at the anode 5A. Then, the hydrogen ions pass through the electrolyte membrane 4 and move to the cathode 5C, and the electrons move to the cathode 5C via the power supply 13, where the hydrogen ions and the electrons combine to generate hydrogen gas.

  Of the hydrogen-containing gas supplied to the anode 5A, the hydrogen-containing gas remaining on the anode 5A without permeating the cathode 5C (the hydrogen-containing gas not used for hydrogen generation at the cathode 5C) is a hydrogen-containing off-gas. And discharged from the anode side outlet 12A.

  The electrolyte membrane 4 is made of a polymer. In particular, although the electrolyte membrane 4 is composed of a small amount of carbon monoxide and carbon dioxide, it permeates a small amount of carbon monoxide and carbon dioxide from the cathode outlet 12C. For example, a hydrogen-containing gas having a hydrogen purity of 99.97% is discharged.

  In S3, the controller 15 determines the hydrogen gas flow rate based on the flow rate of the hydrogen gas generated at the cathode 5C, the current value instructed by the power supply 13, and the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17. Calculate the purification efficiency.

  The hydrogen purification efficiency is represented by the ratio of the energy of hydrogen obtained from the cathode 5C to the electric energy supplied to the power supply 13.

  The flow rate (NL / s) of the hydrogen gas generated at the cathode 5C is calculated using the current value (A) and the flow rate of the returning hydrogen gas that passes through the electrolyte membrane 4 from the cathode 5C to the anode 5A and returns as follows. It can be represented by 1).

ここで、戻り水素ガス流量は、電解質膜４の種類、厚み、含水率及びアノード５Ａとカ
ソード５Ｃの水素ガスの分圧に依存する。本実施の形態においては、戻り水素ガス流量は０．００３５（ＮＬ／ｓ）であり、電流値は９０（Ａ）であるので、水素ガス流量は０．１１１４ＮＬ／ｓとなる。

Here, the flow rate of the returned hydrogen gas depends on the type, thickness, and water content of the electrolyte membrane 4 and the partial pressure of the hydrogen gas at the anode 5A and the cathode 5C. In the present embodiment, since the return hydrogen gas flow rate is 0.0035 (NL / s) and the current value is 90 (A), the hydrogen gas flow rate is 0.1114 NL / s.

  Accordingly, the hydrogen energy obtained from the cathode 5C can be expressed by the following (Equation 2) using the hydrogen gas flow rate (NL / s), 22.4, and the higher calorific value of hydrogen 285800 (kJ / mol).

また、電源１３に投入する電気エネルギーは、電流値（Ａ）と電圧（Ｖ）から計算できる。したがって、水素純化効率は、下記の（数３）で計算することができる。

The electric energy to be supplied to the power supply 13 can be calculated from the current value (A) and the voltage (V). Therefore, the hydrogen purification efficiency can be calculated by the following (Equation 3).

Ｓ４において、水素純化効率が１８以下に低下したかどうかを判定する。そして、水素純化効率が１８以下に低下した場合はＳ５に移行し、Ｓ５において、電流一定で運転することを取りやめ、燃料利用率が１１０％となるように電流値を１１０Ａに大きくして、水素ガス欠乏運転を行い、Ｓ６に進む。Ｓ４において、水素純化効率が１８よりも高い場合は、再びＳ３に戻る。

In S4, it is determined whether the hydrogen purification efficiency has decreased to 18 or less. When the hydrogen purification efficiency drops to 18 or less, the process proceeds to S5, in which the operation at a constant current is stopped, and the current value is increased to 110A so that the fuel utilization rate becomes 110%, and the hydrogen value is increased. A gas-deficient operation is performed, and the process proceeds to S6. In step S4, if the hydrogen purification efficiency is higher than 18, the process returns to step S3.

  In S6, it is determined whether or not the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 has dropped to −0.8 V or less.

  Then, when the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 falls below −0.8 V, the process returns to S2, and in S2, the electrolyte membrane 4 is removed from the anode 5A. The current value of the current flowing in the direction to the cathode 5C via the cathode is set to 90A, and the supply amount of the hydrogen-containing gas supplied by the gas supply means 16 is adjusted so that the fuel utilization becomes 90%.

  In S2, even after adjusting the supply amount of the hydrogen-containing gas from the gas supply means 16 so that the fuel utilization becomes 90%, the operation is performed at a constant current so that the current value of 90A is maintained.

  In S6, when the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 is higher than −0.8 V, the process returns to S6.

As described above, the hydrogen generation system 20 of the present embodiment includes the electrolyte membrane 4, the anode 5 </ b> A disposed on one main surface of the electrolyte membrane 4, and the cathode 5 </ b> C disposed on the other main surface of the electrolyte membrane 4. To form an electrolyte membrane-electrode assembly 9, supplying a hydrogen-containing gas to the anode 5A and flowing a current in a predetermined direction between the anode 5A and the cathode 5C, thereby generating hydrogen at the cathode 5C. 10, a gas supply means 16 for supplying a hydrogen-containing gas, a power supply 13 for flowing a current between the anode 5A and the cathode 5C of the electrochemical device 10, and a controller 15. The fuel utilization rate, which is a ratio obtained by dividing the amount of hydrogen generated at the cathode 5C by the current by the amount of hydrogen supplied to the anode 5A and multiplying by 100, is less than 100% (90%). Hydrogen purification indicating the ratio of the hydrogen energy obtained from the cathode 5C to the electric energy supplied to the power supply 13 when the hydrogen generation system 20 is operating so that the current value of the flow is constant (at 90 A). When the efficiency drops below the threshold (18), the constant current operation is stopped, and the current value of the power supply 13 is increased to 110 A so that the fuel utilization becomes 110%.

  Thereby, when the hydrogen purifying efficiency is reduced to the threshold (18) or less and the hydrogen gas deficient operation with the fuel utilization of 110% is performed, the electrochemical reactions shown in (Chem. 3), (Chem. 4) and (Chem. 5) At the same time, carbon monoxide (poisoning substance) adsorbed on the catalyst of the anode catalyst layer 3A is oxidized and removed by an electrochemical reaction shown in the following (Chem. 6). In Chemical Formula 6, Pt-COad indicates a state in which carbon monoxide is adsorbed on Pt as a catalyst.

（化６）に示す電気化学反応により、アノード触媒層３Ａの触媒の活性部位に吸着した一酸化炭素が酸化除去して取り除かれ、一酸化炭素の吸着により減少したアノード触媒層３Ａの触媒の活性部位が回復する。

The carbon monoxide adsorbed on the active site of the catalyst of the anode catalyst layer 3A is oxidized and removed by the electrochemical reaction shown in Chemical formula 6, and the activity of the catalyst of the anode catalyst layer 3A reduced by the adsorption of carbon monoxide is reduced. The part recovers.

  This makes it possible to recover the decrease in the hydrogen purification efficiency of the electrochemical device 10. By performing this hydrogen gas deficient operation at the timing when the hydrogen purification efficiency has dropped below the threshold value, it is possible to operate the hydrogen generation system 20 with the hydrogen purification efficiency always high.

  The poisoning substance that poisons the catalyst of the anode catalyst layer 3A is not limited to carbon monoxide, and any poisoning substance that can be oxidized and removed by other substances can be used as the active site of the catalyst of the anode catalyst layer 3A. Can be recovered.

  In addition, the threshold value of the hydrogen purification efficiency for making the determination to increase the fuel utilization rate is not limited to 18 employed in the present embodiment, but may be reduced from the initial state according to the electrochemical device used and the operating conditions. It can be set according to the state.

  Note that the fuel utilization rate used in the hydrogen gas deficient operation of the catalyst of the anode catalyst layer 3A is not limited to 110% used in the present embodiment, but may be any fuel utilization rate exceeding 100%. When a substance having a high oxidation-reduction potential is adsorbed, it can be removed by setting a large fuel utilization rate or lengthening the operation time of the hydrogen gas deficient operation.

(Embodiment 2)
The schematic diagram of the hydrogen generation system in the second embodiment of the present invention is the same as the schematic diagram of hydrogen generation system 20 in the first embodiment shown in FIG. FIG. 3 is a flowchart showing a flow of processing executed by the controller in the hydrogen generation system according to Embodiment 2 of the present invention.

  In the hydrogen generation system 20 of the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. The second embodiment is different from the first embodiment in the control operation of the controller 15 (the condition for shifting to the hydrogen gas deficient operation).

The hydrogen generation system 20 according to the first embodiment operates under the control of the controller 15 so that the fuel utilization is less than 100% and the current value of the current from the power supply 13 is constant. Sometimes, when the hydrogen purification efficiency drops below the threshold, the fuel utilization rate becomes 100
% Of hydrogen gas deficient operation.

  On the other hand, the hydrogen generation system 20 according to the second embodiment is controlled by the controller 15 so that the fuel utilization is less than 100% and the current value of the current from the power supply 13 is constant. When the voltage between the anode 5A and the cathode 5C measured by the measuring device 17 rises above the threshold value during the operation of the fuel cell, a hydrogen gas deficient operation in which the fuel utilization exceeds 100% is performed. And

  Hereinafter, the operation and operation of the hydrogen generation system 20 according to Embodiment 2 will be described with reference to FIGS. 1 and 3.

  First, in S11, a hydrogen-containing gas is supplied from the gas supply means 16 to the anode 5A via the anode-side inlet 11A of the electrochemical device 10.

  The hydrogen-containing gas supplied by the gas supply means 16 has a gas temperature of 85 ° C. and a relative humidity of 90%. The hydrogen-containing gas supplied by the gas supply means 16 has a content ratio of carbon monoxide of 0.002%, a content ratio of carbon dioxide of 20%, and a content ratio of hydrogen of 79.998%.

  Next, in S12, a current in a direction of flowing from the anode 5A to the cathode 5C via the electrolyte membrane 4 to the cathode 5C at a current value of 90A is supplied between the anode 5A and the cathode 5C of the electrochemical device 10 by the power source 13, The supply amount of the hydrogen-containing gas from the gas supply means 16 to the electrochemical device 10 is adjusted so that the utilization rate becomes 90%.

  In S12, even after the supply amount of the hydrogen-containing gas from the gas supply means 16 is adjusted so that the fuel utilization rate becomes 90%, the hydrogen generation operation is performed at a constant current so that the current value of 90A is maintained.

  By supplying a current from the anode 5A to the cathode 5C via the electrolyte membrane 4 while the hydrogen-containing gas is being supplied to the anode 5A, the hydrogen contained in the hydrogen-containing gas is dissociated into hydrogen ions and electrons at the anode 5A. Then, the hydrogen ions pass through the electrolyte membrane 4 and move to the cathode 5C, and the electrons move to the cathode 5C via the power supply 13, where the hydrogen ions and the electrons combine to generate hydrogen gas.

  Of the hydrogen-containing gas supplied to the anode 5A, the hydrogen-containing gas remaining on the anode 5A without permeating the cathode 5C (the hydrogen-containing gas not used for hydrogen generation at the cathode 5C) is a hydrogen-containing off-gas. And discharged from the anode side outlet 12A.

  The electrolyte membrane 4 is made of a polymer. In particular, although the electrolyte membrane 4 is composed of a small amount of carbon monoxide and carbon dioxide, it permeates a small amount of carbon monoxide and carbon dioxide from the cathode outlet 12C. For example, a hydrogen-containing gas having a hydrogen purity of 99.97% is discharged.

  In S13, it is determined whether or not the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 has risen to a threshold value of 30 mV or more.

  When the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 rises to 30 mV or more, the process proceeds to S14, and the fuel utilization rate becomes 110% in S14. As described above, the supply amount of the hydrogen-containing gas supplied by the gas supply means 16 is reduced, the hydrogen gas deficient operation is performed, and the process proceeds to S15.

In S13, when the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 is lower than 30 mV, the process returns to S13 again.

  Next, in S15, when the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 drops to −0.8 V or less, the process returns to S12, and in S12, the anode 5A The current value of the current flowing in the direction from the flow through the electrolyte membrane 4 to the cathode 5C is set to 90 A, and the supply amount of the hydrogen-containing gas supplied by the gas supply means 16 is adjusted so that the fuel utilization becomes 90%.

  In S12, even after the supply amount of the hydrogen-containing gas from the gas supply means 16 is adjusted so that the fuel utilization becomes 90%, the operation is performed at a constant current so that the current value of 90A is maintained.

  In S15, when the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 is higher than −0.8 V, the process returns to S15.

  As described above, the hydrogen generation system 20 of the present embodiment includes the electrolyte membrane 4, the anode 5 </ b> A disposed on one main surface of the electrolyte membrane 4, and the cathode 5 </ b> C disposed on the other main surface of the electrolyte membrane 4. To form an electrolyte membrane-electrode assembly 9, supplying a hydrogen-containing gas to the anode 5A and flowing a current in a predetermined direction between the anode 5A and the cathode 5C, thereby generating hydrogen at the cathode 5C. 10, a gas supply means 16 for supplying a hydrogen-containing gas, a power supply 13 for flowing a current between the anode 5A and the cathode 5C of the electrochemical device 10, and a voltage value between the anode 5A and the cathode 5C. The measuring device 17 includes a measuring device 17 and a controller 15. The controller 15 divides the amount of hydrogen generated at the cathode 5C by the electric current by the amount of hydrogen supplied to the anode 5A and multiplies by 100. When the hydrogen generation system 20 is operated so that the fuel utilization indicating the ratio is less than 100% (90%) and the current value of the current from the power supply 13 is constant (at 90 A), When the measured voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 rises to a threshold value (30 mV) or more, the constant current operation is stopped and the gas supply means is set so that the fuel utilization becomes 110%. It is characterized in that the supply amount of the hydrogen-containing gas supplied from 16 to the anode 5A is reduced.

  With this, when the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 rises above the threshold value, when the hydrogen gas deficient operation in which the fuel utilization exceeds 100% is performed, At the same time as the electrochemical reactions shown in Chemical Formulas 3), 4) and 5) occur, the carbon monoxide (poisoning substance) adsorbed on the catalyst of the anode catalyst layer 3A is converted into the electric chemical shown in Chemical Formula 6 It is oxidized and removed by a chemical reaction.

  Therefore, the active site of the catalyst in the anode catalyst layer 3A is recovered, and the decrease in the hydrogen purification efficiency of the electrochemical device 10 can be recovered.

  This hydrogen gas deficient operation is performed at the timing when the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 rises above the threshold value, thereby improving the hydrogen purification efficiency of the hydrogen generation system 20. You can always drive in a high state.

  The poisoning substance that poisons the catalyst of the anode catalyst layer 3A is not limited to carbon monoxide. If the poisoning substance can be oxidized and removed by other substances, the active site of the catalyst of the anode catalyst layer 3A is reduced. Can be recovered.

  Note that the voltage value (threshold) between the anode 5A and the cathode 5C for making a decision to increase the fuel utilization rate is not limited to 30 mV employed in the present embodiment, but may be adjusted according to the electrochemical device used and operating conditions. Thus, it can be set in accordance with an acceptable performance degradation state from the initial state.

  Note that the fuel utilization rate used in the hydrogen gas deficient operation of the catalyst of the anode catalyst layer 3A is not limited to 110% used in the present embodiment, but may be any fuel utilization rate exceeding 100%. When a substance having a high oxidation-reduction potential is adsorbed, it can be removed by setting a large fuel utilization rate or lengthening the operation time of the hydrogen gas deficient operation.

(Embodiment 3)
The schematic diagram of the hydrogen generation system in the third embodiment of the present invention is the same as the schematic diagram of hydrogen generation system 20 in the first embodiment shown in FIG. FIG. 4 is a flowchart showing a flow of processing executed by the controller in the hydrogen generation system according to Embodiment 3 of the present invention.

  In the hydrogen generation system 20 of the third embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. The third embodiment is different from the first embodiment in the control operation of the controller 15 (the condition for shifting to the hydrogen gas deficient operation).

  The hydrogen generation system 20 according to the first embodiment operates under the control of the controller 15 so that the fuel utilization is less than 100% and the current value of the current from the power supply 13 is constant. Sometimes, when the hydrogen purification efficiency drops below the threshold value, a hydrogen gas deficient operation in which the fuel utilization exceeds 100% is performed.

  On the other hand, the hydrogen generation system 20 according to the third embodiment operates under the control of the controller 15 such that the fuel utilization is less than 100% and the voltage between the anode 5A and the cathode 5C is constant. When the generation system 20 is operating, when the current value of the power supply 13 becomes smaller than the threshold value, a hydrogen gas deficient operation in which the fuel utilization exceeds 100% is performed.

  Hereinafter, the operation and operation of the hydrogen generation system 20 according to Embodiment 3 will be described with reference to FIGS. 1 and 4.

  First, in S21, a hydrogen-containing gas is supplied from the gas supply means 16 to the anode 5A via the anode-side inlet 11A of the electrochemical device 10.

  The hydrogen-containing gas supplied by the gas supply means 16 has a gas temperature of 85 ° C. and a relative humidity of 90%. The hydrogen-containing gas supplied by the gas supply means 16 has a content ratio of carbon monoxide of 0.002%, a content ratio of carbon dioxide of 20%, and a content ratio of hydrogen of 79.998%.

  Next, in S22, the power source 13 causes a current of 90 A to flow between the anode 5A and the cathode 5C of the electrochemical device 10 in a direction from the anode 5A to the cathode 5C via the electrolyte membrane 4, thereby causing the fuel to flow. The supply amount of the hydrogen-containing gas from the gas supply means 16 to the electrochemical device 10 is adjusted so that the utilization rate becomes 90%.

  In S22, after adjusting the supply amount of the hydrogen-containing gas from the gas supply means 16 so that the fuel utilization rate becomes 90%, the distance between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 is measured. The hydrogen generation operation is performed at a constant voltage so that the above voltage value is maintained.

By supplying a current from the anode 5A to the cathode 5C via the electrolyte membrane 4 while the hydrogen-containing gas is being supplied to the anode 5A, the hydrogen contained in the hydrogen-containing gas is dissociated into hydrogen ions and electrons at the anode 5A. The hydrogen ions pass through the electrolyte membrane 4 and pass through the cathode 5
C, the electrons move to the cathode 5C via the power source 13, and at the cathode 5C, hydrogen ions and electrons are combined to generate hydrogen gas.

  Of the hydrogen-containing gas supplied to the anode 5A, the hydrogen-containing gas remaining on the anode 5A without permeating the cathode 5C (the hydrogen-containing gas not used for hydrogen generation at the cathode 5C) is a hydrogen-containing off-gas. And discharged from the anode side outlet 12A.

  The electrolyte membrane 4 is made of a polymer. In particular, although the electrolyte membrane 4 is composed of a small amount of carbon monoxide and carbon dioxide, it permeates a small amount of carbon monoxide and carbon dioxide from the cathode outlet 12C. For example, a hydrogen-containing gas having a hydrogen purity of 99.97% is discharged.

  In S23, it is determined whether the current value of the power supply 13 has become smaller than the threshold value of 70A or less. Then, when the current value of the power supply 13 becomes 70 A or less, the process proceeds to S24. In S24, the constant voltage operation is canceled, and the current value of the power supply 13 is increased so that the fuel utilization becomes 110%. A hydrogen gas deficient operation is performed, and the process proceeds to S25. In S23, when the current value of the power supply 13 is larger than 70A, the process returns to S23 again.

  In S25, it is determined whether or not the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 has dropped to −0.8 V or less.

  Then, when the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 decreases to −0.8 V or less, the process returns to S22. The current value of the current flowing in the direction to the cathode 5C via the line 4 is set to 90A, and the supply amount of the hydrogen-containing gas supplied by the gas supply means 16 is adjusted so that the fuel utilization rate becomes 90%.

  In S22, after adjusting the supply amount of the hydrogen-containing gas from the gas supply means 16 so that the fuel utilization rate becomes 90%, the distance between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 is measured. The hydrogen generation operation is performed at a constant voltage so that the above voltage value is maintained.

  In S25, when the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 is higher than −0.8 V, the process returns to S25.

  As described above, the hydrogen generation system 20 of the present embodiment includes the electrolyte membrane 4, the anode 5 </ b> A disposed on one main surface of the electrolyte membrane 4, and the cathode 5 </ b> C disposed on the other main surface of the electrolyte membrane 4. To form an electrolyte membrane-electrode assembly 9, supplying a hydrogen-containing gas to the anode 5A and flowing a current in a predetermined direction between the anode 5A and the cathode 5C, thereby generating hydrogen at the cathode 5C. 10, a gas supply means 16 for supplying a hydrogen-containing gas, a power supply 13 for flowing a current between the anode 5A and the cathode 5C of the electrochemical device 10, and a voltage value between the anode 5A and the cathode 5C. The measuring device 17 includes a measuring device 17 and a controller 15. The controller 15 divides the amount of hydrogen generated at the cathode 5C by the current by the amount of hydrogen supplied to the anode 5A and multiplies by 100. When the hydrogen generation system 20 is operated so that the fuel utilization indicating the ratio is less than 100% (90%) and the voltage between the anode 5A and the cathode 5C is constant, the current value of the power supply 13 Is smaller than the threshold value (70 A), the constant voltage operation is stopped, and the current value of the power supply 13 is increased so that the fuel utilization rate becomes 110%.

Accordingly, when the hydrogen generation system 20 is operated so that the voltage between the anode 5A and the cathode 5C becomes constant, when the current value of the power supply 13 becomes smaller than the threshold value (70A), the fuel utilization is performed. When a hydrogen gas deficient operation with a rate exceeding 100% is performed, (Chem. 3), (Chem. 4)
At the same time as the electrochemical reaction shown in (Chem. 5) occurs, carbon monoxide (poisoning substance) adsorbed on the catalyst of the anode catalyst layer 3A is oxidized and removed by the electrochemical reaction shown in (Chem. 6).

  Therefore, the active site of the catalyst in the anode catalyst layer 3A is recovered, and the decrease in the hydrogen purification efficiency of the electrochemical device 10 can be recovered. By performing the hydrogen gas deficient operation at the timing when the current value of the power supply 13 becomes smaller than or equal to the threshold value, the hydrogen generation system 20 can always be operated with a high hydrogen purification efficiency.

  The poisoning substance that poisons the catalyst of the anode catalyst layer 3A is not limited to carbon monoxide. If the poisoning substance can be oxidized and removed by other substances, the active site of the catalyst of the anode catalyst layer 3A is changed. Can be recovered.

  The current value (threshold value) for making a decision to increase the fuel utilization rate is not limited to 70 A adopted in the present embodiment, but may be reduced from the initial state according to the electrochemical device used and the operating conditions. It can be set according to the state.

  Note that the fuel utilization rate used in the hydrogen gas deficient operation of the catalyst of the anode catalyst layer 3A is not limited to 110% used in the present embodiment, but may be any fuel utilization rate exceeding 100%. When a substance having a high oxidation-reduction potential is adsorbed, it can be removed by setting a large fuel utilization rate or lengthening the operation time of the hydrogen gas deficient operation.

(Embodiment 4)
FIG. 5 shows a schematic diagram of a hydrogen generation system according to Embodiment 4 of the present invention. FIG. 6 is a flowchart showing a flow of processing executed by the controller in the hydrogen generation system according to Embodiment 4 of the present invention.

  In the hydrogen generation system 30 of the fourth embodiment shown in FIG. 5, the same components as those of the hydrogen generation system 20 of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

  The hydrogen generation system 30 according to the fourth embodiment is the same as the hydrogen generation system 20 according to the first embodiment, except that the first flow meter 18 measures the flow rate of hydrogen gas discharged from the cathode-side outlet 12C of the electrochemical device 10 to the cathode discharge path. Is provided.

  Further, the hydrogen generation system 30 of the fourth embodiment differs from the hydrogen generation system 20 of the first embodiment in the control operation of the controller 15 (conditions for shifting to the hydrogen gas deficient operation).

  The hydrogen generation system 20 according to the first embodiment operates under the control of the controller 15 so that the fuel utilization is less than 100% and the current value of the current from the power supply 13 is constant. Sometimes, when the hydrogen purification efficiency drops below the threshold value, a hydrogen gas deficient operation in which the fuel utilization exceeds 100% is performed.

  On the other hand, the hydrogen generation system 30 according to the fourth embodiment operates under the control of the controller 15 so that the fuel utilization is less than 100% and the voltage between the anode 5A and the cathode 5C is constant. During the operation of the generation system 30, the flow rate of hydrogen measured by the first flow meter 18 decreased below the threshold. The voltage between the anode 5A and the cathode 5C measured by the measuring instrument 17 rose above the threshold. In this case, a hydrogen gas deficient operation in which the fuel utilization exceeds 100% is performed.

Hereinafter, the operation and operation of the hydrogen generation system 30 according to the fourth embodiment will be described with reference to FIGS.

  First, in S31, a hydrogen-containing gas is supplied from the gas supply means 16 to the anode 5A via the anode-side inlet 11A of the electrochemical device 10.

  The hydrogen-containing gas supplied by the gas supply means 16 has a gas temperature of 85 ° C. and a relative humidity of 90%. The hydrogen-containing gas supplied by the gas supply means 16 has a content ratio of carbon monoxide of 0.002%, a content ratio of carbon dioxide of 20%, and a content ratio of hydrogen of 79.998%.

  Next, in S32, a current in a direction of flowing from the anode 5A to the cathode 5C through the electrolyte membrane 4 to the cathode 5C at a current value of 90A is supplied between the anode 5A and the cathode 5C of the electrochemical device 10 by the power source 13, The supply amount of the hydrogen-containing gas from the gas supply means 16 to the electrochemical device 10 is adjusted so that the utilization rate becomes 90%.

  In S32, after adjusting the supply amount of the hydrogen-containing gas from the gas supply means 16 so that the fuel utilization rate becomes 90%, the distance between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 is measured. The hydrogen generation operation is performed at a constant voltage so that the above voltage value is maintained.

  By supplying a current from the anode 5A to the cathode 5C via the electrolyte membrane 4 while the hydrogen-containing gas is being supplied to the anode 5A, the hydrogen contained in the hydrogen-containing gas is dissociated into hydrogen ions and electrons at the anode 5A. Then, the hydrogen ions pass through the electrolyte membrane 4 and move to the cathode 5C, and the electrons move to the cathode 5C via the power supply 13, where the hydrogen ions and the electrons combine to generate hydrogen gas.

  Of the hydrogen-containing gas supplied to the anode 5A, the hydrogen-containing gas remaining on the anode 5A without permeating the cathode 5C (the hydrogen-containing gas not used for hydrogen generation at the cathode 5C) is a hydrogen-containing off-gas. And discharged from the anode side outlet 12A.

  The electrolyte membrane 4 is made of a polymer. In particular, although the electrolyte membrane 4 is composed of a small amount of carbon monoxide and carbon dioxide, it permeates a small amount of carbon monoxide and carbon dioxide from the cathode outlet 12C. For example, a hydrogen-containing gas having a hydrogen purity of 99.97% is discharged.

  In S33, the flow rate of the hydrogen gas discharged from the cathode side outlet 12C to the cathode discharge path is measured by the first flow meter 18, and the flow rate of the hydrogen gas measured by the first flow meter 18 is 0.07 NL / threshold. It is determined whether it has decreased to s or less.

  If the flow rate of the hydrogen gas measured by the first flow meter 18 has decreased to 0.07 NL / s or less, the process proceeds to S34, in which the constant voltage operation is stopped, and the fuel utilization rate becomes 110%. Then, the supply amount of the hydrogen-containing gas supplied from the gas supply means 16 to the electrochemical device 10 is reduced, a hydrogen gas deficient operation is performed, and the process proceeds to S35.

  In S33, when the flow rate of the hydrogen gas measured by the first flow meter 18 is larger than 0.07 NL / s, the process returns to S33 again.

  In S35, it is determined whether or not the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 has dropped to −0.8 V or less.

Then, when the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 drops to −0.8 V or less, the process returns to S32, and in S32, the electrolyte membrane is connected from the anode 5A to the electrolyte membrane. The current value of the current flowing in the direction to the cathode 5C via the line 4 is set to 90A, and the supply amount of the hydrogen-containing gas supplied by the gas supply means 16 is adjusted so that the fuel utilization rate becomes 90%.

  In S32, after adjusting the supply amount of the hydrogen-containing gas from the gas supply means 16 so that the fuel utilization rate becomes 90%, the distance between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 is measured. The hydrogen generation operation is performed at a constant voltage so that the above voltage value is maintained.

  In S35, when the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 is higher than −0.8 V, the process returns to S35 again.

  As described above, the hydrogen generation system 30 of the present embodiment includes the electrolyte membrane 4, the anode 5 </ b> A disposed on one main surface of the electrolyte membrane 4, and the cathode 5 </ b> C disposed on the other main surface of the electrolyte membrane 4. To form an electrolyte membrane-electrode assembly 9, supplying a hydrogen-containing gas to the anode 5A and flowing a current in a predetermined direction between the anode 5A and the cathode 5C, thereby generating hydrogen at the cathode 5C. 10, a gas supply means 16 for supplying a hydrogen-containing gas, a power supply 13 for flowing a current between the anode 5A and the cathode 5C of the electrochemical device 10, and a voltage value between the anode 5A and the cathode 5C. A measuring device 17 for measuring, a first flow meter 18 for measuring a flow rate of hydrogen gas discharged from the cathode 5C, and a controller 15 are provided. When the fuel utilization rate, which is a ratio of the generated hydrogen amount divided by the hydrogen amount supplied to the anode 5A and multiplied by 100, is less than 100% (90%), the voltage between the anode 5A and the cathode 5C becomes constant. As described above, when the hydrogen generation system 30 is operating and the flow rate of the hydrogen gas measured by the first flow meter 18 decreases below the threshold value (0.07 NL / s), the constant voltage operation is stopped. In addition, the supply amount of the hydrogen-containing gas supplied from the gas supply means 16 to the anode 5A is reduced so that the fuel utilization rate becomes 110%.

  As a result, the flow rate of the hydrogen gas measured by the first flow meter 18 decreases below the threshold value while the hydrogen generation system 30 is operating so that the voltage between the anode 5A and the cathode 5C becomes constant. In this case, when a hydrogen gas deficiency operation in which the fuel utilization exceeds 100% is performed, the electrochemical reactions shown in (Chem. 3), (Chem. 4) and (Chem. 5) occur, and at the same time, the catalyst of the anode catalyst layer 3A The carbon monoxide (poisonous substance) adsorbed on the surface is oxidized and removed by an electrochemical reaction shown in (Chem. 6).

  Therefore, the active site of the catalyst in the anode catalyst layer 3A is recovered, and the decrease in hydrogen purification efficiency can be recovered. By performing the hydrogen gas deficient operation at a timing when the amount of hydrogen generated at the cathode is reduced to a threshold value or less, the hydrogen generation system 30 can always be operated with a high hydrogen purification efficiency.

  The poisoning substance that poisons the catalyst of the anode catalyst layer 3A is not limited to carbon monoxide. If the poisoning substance can be oxidized and removed by other substances, the active site of the catalyst of the anode catalyst layer 3A is changed. Can be recovered.

  The flow rate value (threshold value) of the first flow meter 18 for making a determination to increase the fuel utilization rate is not limited to 0.07 NL / s adopted in the present embodiment, but depends on the electrochemical device used and operating conditions. At the same time, the setting can be made in accordance with the permissible performance reduction state from the initial state.

Note that the fuel utilization rate used in the hydrogen gas deficient operation of the catalyst of the anode catalyst layer 3A is not limited to 110% used in the present embodiment, but may be any fuel utilization rate exceeding 100%. When a substance having a high oxidation-reduction potential is adsorbed, it can be removed by setting a large fuel utilization rate or lengthening the operation time of the hydrogen gas deficient operation.

(Embodiment 5)
FIG. 7 shows a schematic diagram of a hydrogen generation system according to Embodiment 5 of the present invention. FIG. 8 is a flowchart showing a flow of processing executed by the controller in the hydrogen generation system according to Embodiment 5 of the present invention.

  In the hydrogen generation system 40 of the fifth embodiment shown in FIG. 7, the same components as those of the hydrogen generation system 20 of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

  The hydrogen generation system 40 according to the fifth embodiment is the same as the hydrogen generation system 20 according to the first embodiment, except that the second flow rate measures the flow rate of the hydrogen-containing off-gas discharged from the anode-side outlet 12A of the electrochemical device 10 to the anode discharge path. In this configuration, a total of 19 is provided.

  Furthermore, the hydrogen generation system 40 of the fifth embodiment is different from the hydrogen generation system 20 of the first embodiment in the control operation of the controller 15 (the condition for shifting to the hydrogen gas deficient operation).

  The hydrogen generation system 20 according to the first embodiment operates under the control of the controller 15 so that the fuel utilization is less than 100% and the current value of the current from the power supply 13 is constant. Sometimes, when the hydrogen purification efficiency drops below the threshold value, a hydrogen gas deficient operation in which the fuel utilization exceeds 100% is performed.

  On the other hand, the hydrogen generation system 40 of the fifth embodiment operates under the control of the controller 15 so that the fuel utilization rate is less than 100% and the voltage between the anode 5A and the cathode 5C is constant. If the flow rate of the hydrogen-containing off-gas discharged from the anode-side outlet 12A to the anode discharge path measured by the second flow meter 19 increases to a threshold value or more while operating the generation system 40, the fuel utilization rate becomes 100%. % Hydrogen-starved operation.

  Hereinafter, the operation and operation of the hydrogen generation system 40 according to the fifth embodiment will be described with reference to FIGS. 7 and 8.

  First, in S41, a hydrogen-containing gas is supplied from the gas supply means 16 to the anode 5A via the anode-side inlet 11A of the electrochemical device 10.

  The hydrogen-containing gas supplied by the gas supply means 16 has a gas temperature of 85 ° C. and a relative humidity of 90%. The hydrogen-containing gas supplied by the gas supply means 16 has a content ratio of carbon monoxide of 0.002%, a content ratio of carbon dioxide of 20%, and a content ratio of hydrogen of 79.998%.

  Next, in S42, a current in a direction of flowing from the anode 5A to the cathode 5C via the electrolyte membrane 4 to the cathode 5C with a current value of 90A is supplied between the anode 5A and the cathode 5C of the electrochemical device 10 by the power source 13, The supply amount of the hydrogen-containing gas from the gas supply means 16 to the electrochemical device 10 is adjusted so that the utilization rate becomes 90%.

  In S42, after adjusting the supply amount of the hydrogen-containing gas from the gas supply means 16 so that the fuel utilization rate becomes 90%, the distance between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 is measured. The hydrogen generation operation is performed at a constant voltage so that the above voltage value is maintained.

  By supplying a current from the anode 5A to the cathode 5C via the electrolyte membrane 4 while the hydrogen-containing gas is being supplied to the anode 5A, the hydrogen contained in the hydrogen-containing gas is dissociated into hydrogen ions and electrons at the anode 5A. Then, the hydrogen ions pass through the electrolyte membrane 4 and move to the cathode 5C, and the electrons move to the cathode 5C via the power supply 13, where the hydrogen ions and the electrons combine to generate hydrogen gas.

  Of the hydrogen-containing gas supplied to the anode 5A, the hydrogen-containing gas remaining on the anode 5A without permeating the cathode 5C (the hydrogen-containing gas not used for hydrogen generation at the cathode 5C) is a hydrogen-containing off-gas. And discharged from the anode side outlet 12A.

  The electrolyte membrane 4 is made of a polymer. In particular, although the electrolyte membrane 4 is composed of a small amount of carbon monoxide and carbon dioxide, it permeates a small amount of carbon monoxide and carbon dioxide from the cathode outlet 12C. For example, a hydrogen-containing gas having a hydrogen purity of 99.97% is discharged.

  In S43, the flow rate of the hydrogen-containing off-gas discharged from the anode-side outlet 12A of the electrochemical device 10 to the anode discharge path is measured by the second flow meter 19, and the flow rate of the hydrogen-containing off-gas is measured by the second flow meter 19 from the anode-side outlet 12A. It is determined whether the flow rate of the hydrogen-containing off-gas discharged to the discharge path has increased to a threshold value of 0.035 NL / s or more.

  When the flow rate of the hydrogen-containing off-gas discharged from the anode-side outlet 12A to the anode discharge path measured by the second flow meter 19 has increased to 0.035 NL / s or more, the process proceeds to S44, and in S44, the voltage is The constant operation is stopped, the current value of the power supply 13 is increased so that the fuel utilization becomes 110%, a hydrogen gas deficient operation is performed, and the process proceeds to S45.

  In S43, when the flow rate of the hydrogen-containing off-gas discharged from the anode-side outlet 12A to the anode discharge path measured by the second flow meter 19 is less than 0.035 NL / s, the process returns to S43.

  In S45, it is determined whether or not the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 has dropped to −0.8 V or less.

  Then, when the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 drops to −0.8 V or less, the process returns to S42. The current value of the current flowing in the direction to the cathode 5C via the line 4 is set to 90A, and the supply amount of the hydrogen-containing gas supplied by the gas supply means 16 is adjusted so that the fuel utilization rate becomes 90%.

  In S42, after adjusting the supply amount of the hydrogen-containing gas from the gas supply means 16 so that the fuel utilization rate becomes 90%, the distance between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 is measured. The hydrogen generation operation is performed at a constant voltage so that the above voltage value is maintained.

  In S45, when the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring device 17 is higher than −0.8 V, the process returns to S45 again.

As described above, the hydrogen generation system 40 of the present embodiment includes the electrolyte membrane 4, the anode 5 </ b> A arranged on one main surface of the electrolyte membrane 4, and the cathode 5 </ b> C arranged on the other main surface of the electrolyte membrane 4. To form an electrolyte membrane-electrode assembly 9, supplying a hydrogen-containing gas to the anode 5A and flowing a current in a predetermined direction between the anode 5A and the cathode 5C, thereby generating hydrogen at the cathode 5C. 10, a gas supply means 16 for supplying a hydrogen-containing gas, a power supply 13 for flowing a current between the anode 5A and the cathode 5C of the electrochemical device 10, and a voltage value between the anode 5A and the cathode 5C. A measuring device 17 for measuring, a second flow meter 19 for measuring a flow rate of the hydrogen-containing off-gas discharged from the anode 5A, and a controller 15 are provided. The amount of hydrogen generated in the anode 5A is divided by the amount of hydrogen supplied to the anode 5A and multiplied by 100, and the fuel utilization is less than 100% (90%), and the voltage between the anode 5A and the cathode 5C is less than 100%. If the flow rate of the hydrogen-containing off-gas measured by the second flow meter 19 increases to be equal to or more than the threshold (0.035 NL / s) while operating the hydrogen generation system 40 so as to be constant, the voltage is kept constant. The operation is stopped, and the current value of the power supply 13 is increased so that the fuel utilization rate becomes 110%.

  Thereby, when the hydrogen generation system 40 is operated so that the voltage between the anode 5A and the cathode 5C becomes constant, the flow rate of the hydrogen-containing off-gas measured by the second flow meter 19 becomes equal to or higher than the threshold value. When the hydrogen gas deficiency operation in which the fuel utilization exceeds 100% is performed in the case of the increase, the electrochemical reactions shown in (Chem. 3), (Chem. 4) and (Chem. 5) occur, and at the same time, the anode catalyst layer 3A The carbon monoxide (poisonous substance) adsorbed on the catalyst is oxidized and removed by an electrochemical reaction shown in (Chem. 6).

  Therefore, the active site of the catalyst in the anode catalyst layer 3A is recovered, and the decrease in hydrogen purification efficiency can be recovered. By performing the hydrogen gas deficient operation at a timing when the flow rate of the hydrogen-containing off-gas discharged from the anode 5A increases to a threshold value or more, the hydrogen purification system 40 can always be operated with a high hydrogen purification efficiency.

  The poisoning substance that poisons the catalyst of the anode catalyst layer 3A is not limited to carbon monoxide. If the poisoning substance can be oxidized and removed by other substances, the active site of the catalyst of the anode catalyst layer 3A is changed. Can be recovered.

  In addition, the flow value (threshold) of the second flow meter 19 for determining to increase the fuel utilization rate is not limited to 0.035 NL / s adopted in the present embodiment, but depends on the electrochemical device used and the operating conditions. At the same time, the setting can be made in accordance with the permissible performance reduction state from the initial state.

  Note that the fuel utilization rate used in the hydrogen gas deficient operation of the catalyst of the anode catalyst layer 3A is not limited to 110% used in the present embodiment, but may be any fuel utilization rate exceeding 100%. When a substance having a high oxidation-reduction potential is adsorbed, it can be removed by setting a large fuel utilization rate or lengthening the operation time of the hydrogen gas deficient operation.

  As described above, the hydrogen generation system and the method for operating the same according to the present invention remove the impurities adsorbed on the catalyst of the anode catalyst layer while maintaining the performance of generating hydrogen at a high level, and improve the hydrogen purification efficiency of the electrochemical device. Therefore, the present invention can also be applied to uses such as removal of impurities of an electrochemical device which refuses to mix another gas.

Reference Signs List 1A anode separator 1C cathode separator 2A anode gas diffusion layer 2C cathode gas diffusion layer 3A anode catalyst layer 3C cathode catalyst layer 4 electrolyte membrane 5A anode 5C cathode 9 electrolyte membrane-electrode assembly 10 electrochemical device 11A anode side inlet 12A anode side outlet 12C Cathode side outlet 13 Power supply 14A Anode gas flow path 14C Cathode gas flow path 15 Controller 16 Gas supply means 17 Measuring instrument 18 First flow meter 19 Second flow meter 20, 30, 40 Hydrogen generation system

Claims (6)

An electrolyte membrane and an anode arranged on one main surface of the electrolyte membrane and a cathode arranged on the other main surface of the electrolyte membrane constitute an electrolyte membrane-electrode assembly, and a hydrogen-containing gas is supplied to the anode. An electrochemical device that generates hydrogen at the cathode by flowing a current in a predetermined direction between the anode and the cathode,
Gas supply means for supplying the hydrogen-containing gas,
A power supply for flowing the current between the anode and the cathode;
A hydrogen generation system comprising: a controller;
The controller determines that the fuel utilization rate, which is a ratio of the amount of hydrogen generated at the cathode by the current divided by the amount of hydrogen supplied to the anode and multiplied by 100, is less than 100%; As the value becomes constant, the hydrogen purification efficiency indicating the ratio of the hydrogen energy obtained from the cathode to the electric energy supplied to the power supply is reduced below the threshold when the hydrogen generation system is operating. In this case, at least one of increasing the current value of the power supply or decreasing the flow rate of the hydrogen-containing gas supplied from the gas supply unit is performed so that the fuel utilization rate exceeds 100%. A hydrogen generation system, characterized in that: An electrolyte membrane and an anode arranged on one main surface of the electrolyte membrane and a cathode arranged on the other main surface of the electrolyte membrane constitute an electrolyte membrane-electrode assembly, and a hydrogen-containing gas is supplied to the anode. An electrochemical device that generates hydrogen at the cathode by flowing a current in a predetermined direction between the anode and the cathode,
Gas supply means for supplying the hydrogen-containing gas,
A power supply for flowing the current between the anode and the cathode;
A measuring instrument for measuring a voltage between the anode and the cathode,
A hydrogen generation system comprising: a controller;
The controller determines that the fuel utilization rate, which is a ratio of the amount of hydrogen generated at the cathode by the current divided by the amount of hydrogen supplied to the anode and multiplied by 100, is less than 100%; In order to keep the value constant, when operating the hydrogen generation system, when the voltage between the anode and the cathode measured by the measuring device rises above a threshold, the fuel utilization rate is increased. At least one of increasing the current value of the power supply or decreasing the flow rate of the hydrogen-containing gas supplied from the gas supply unit so as to exceed 100% is performed. . An electrolyte membrane and an anode arranged on one main surface of the electrolyte membrane and a cathode arranged on the other main surface of the electrolyte membrane constitute an electrolyte membrane-electrode assembly, and a hydrogen-containing gas is supplied to the anode. An electrochemical device that generates hydrogen at the cathode by flowing a current in a predetermined direction between the anode and the cathode,
Gas supply means for supplying the hydrogen-containing gas,
A power supply for flowing the current between the anode and the cathode;
A measuring instrument for measuring a voltage between the anode and the cathode,
A hydrogen generation system comprising: a controller;
The controller is configured to divide the amount of hydrogen generated at the cathode by the current by the amount of hydrogen supplied to the anode and multiply by 100 to obtain a fuel utilization ratio of less than 100%. When the hydrogen generation system is operated so that the voltage between them becomes constant, at least when the current value of the power supply becomes smaller than the threshold value, the fuel utilization exceeds 100%. A hydrogen generation system, which performs one of increasing a current value of the power supply or decreasing a flow rate of the hydrogen-containing gas supplied from the gas supply unit. An electrolyte membrane and an anode arranged on one main surface of the electrolyte membrane and a cathode arranged on the other main surface of the electrolyte membrane constitute an electrolyte membrane-electrode assembly, and a hydrogen-containing gas is supplied to the anode. An electrochemical device that generates hydrogen at the cathode by flowing a current in a predetermined direction between the anode and the cathode,
Gas supply means for supplying the hydrogen-containing gas,
A power supply for flowing the current between the anode and the cathode;
A first flow meter for measuring a flow rate of hydrogen discharged from the cathode,
A hydrogen generation system comprising: a controller;
The controller is configured to divide the amount of hydrogen generated at the cathode by the current by the amount of hydrogen supplied to the anode and multiply by 100 to obtain a fuel utilization rate of less than 100%. During the operation of the hydrogen generation system, when the flow rate of hydrogen measured by the first flow meter decreases below a threshold so that the voltage between the fuel cells becomes constant, the fuel utilization rate decreases to 100%. A hydrogen generation system characterized by performing at least one of increasing the current value of the power supply or decreasing the flow rate of the hydrogen-containing gas supplied from the gas supply unit so as to exceed the above value. An electrolyte membrane and an anode arranged on one main surface of the electrolyte membrane and a cathode arranged on the other main surface of the electrolyte membrane constitute an electrolyte membrane-electrode assembly, and a hydrogen-containing gas is supplied to the anode. An electrochemical device that generates hydrogen at the cathode by flowing a current in a predetermined direction between the anode and the cathode,
Gas supply means for supplying the hydrogen-containing gas,
A power supply for flowing the current between the anode and the cathode;
A second flow meter for measuring the flow rate of the hydrogen-containing off-gas discharged from the anode,
A hydrogen generation system comprising: a controller;
The controller is configured to divide the amount of hydrogen generated at the cathode by the current by the amount of hydrogen supplied to the anode and multiply by 100 to obtain a fuel utilization rate of less than 100%. During the operation of the hydrogen generation system, when the flow rate of the hydrogen-containing off-gas measured by the second flow meter increases to a threshold value or more, so that the voltage between the fuel cells becomes constant, the fuel utilization rate increases. At least one of increasing the current value of the power supply or decreasing the flow rate of the hydrogen-containing gas supplied from the gas supply unit so as to exceed 100% is performed. . An electrolyte membrane and an anode arranged on one main surface of the electrolyte membrane and a cathode arranged on the other main surface of the electrolyte membrane constitute an electrolyte membrane-electrode assembly, and a hydrogen-containing gas is supplied to the anode. An electrochemical device that generates hydrogen at the cathode by flowing a current in a predetermined direction between the anode and the cathode,
Gas supply means for supplying the hydrogen-containing gas,
A power supply for flowing a current between the anode and the cathode of the electrochemical device, comprising:
The amount of hydrogen generated at the cathode by the current divided by the amount of hydrogen supplied to the anode and multiplied by 100 is less than 100%, and the current value of the current by the power supply is constant. As described above, when the hydrogen generation system is operating, when the hydrogen purification efficiency indicating the ratio of the hydrogen energy obtained from the cathode to the electric energy supplied to the power supply is reduced to a threshold or less, the anode and Either the case where the voltage between the cathode and the voltage rises above a threshold, or
When operating the hydrogen generation system, the current value of the power supply decreases below a threshold so that the fuel utilization is less than 100% and the voltage between the anode and the cathode is constant. Either when the flow rate of hydrogen discharged from the cathode decreases below a threshold or when the flow rate of hydrogen-containing off gas discharged from the anode increases above a threshold,
At least one of increasing the current value of the power supply or decreasing the flow rate of the hydrogen-containing gas supplied from the gas supply unit so that the fuel utilization exceeds 100%. Characteristic method of operating a hydrogen generation system.

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