JP7033701B2 - Hydrogen generation system - Google Patents

Description

The present invention relates to a hydrogen generation system that produces high-purity hydrogen from a hydrogen-containing gas by utilizing an electrochemical reaction.

Conventionally, an electrochemical device that produces high-purity hydrogen from a hydrogen-containing gas using an electrolyte membrane-electrode assembly in which an electrolyte membrane that selectively transports hydrogen ions is arranged between an anode and a cathode has been known. Has been done.

When a humidified hydrogen-containing gas is supplied to the anode of this electrochemical device and a current is passed from the anode to the cathode through the electrolyte membrane, the hydrogen shown in (Chemical formula 1) is hydrogen ion (H) at the anode. An oxidation reaction that dissociates into electrons occurs with ⁺ ), and a reduction reaction occurs at the cathode where hydrogen ions (H ⁺ ) shown in (Chemical formula 2) and electrons are combined to generate hydrogen.

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

FIG. 6 is a schematic diagram of a conventional hydrogen generation system. As shown in FIG. 6, the conventional electrochemical device 200 includes an electrolyte membrane-electrode assembly 120, an anode side separator 104, a cathode side separator 105, an anode terminal plate 106, a cathode terminal plate 107, and a voltage application. It is provided with a unit 113.

In the electrolyte membrane-electrode assembly 120, the anode 102 is arranged on one main surface of the electrolyte membrane 101, and the cathode 103 is arranged on the other main surface of the electrolyte membrane 101. The anode 102 and the cathode 103 are mainly composed of a catalyst made of a noble metal such as platinum (Pt) and a catalyst-supported carbon that supports the catalyst.

The anode terminal plate 106 arranged so as to be electrically connected to the anode 102 via the anode-side separator 104 includes a hydrogen-containing gas inlet pipe 110 that supplies hydrogen-containing gas to the anode-side separator 104 and an anode-side separator. A residual gas outlet pipe 112 for deriving the residual gas from 104 is connected.

In the electrochemical device 200, the hydrogen-containing gas from the hydrogen-containing gas inlet pipe 110 is supplied from the anode-side separator 104 to the anode 102, and the residual gas not supplied to the anode 102 is the residual gas outlet from the anode-side separator 104. It is configured to be discharged to the tube 112.

Further, the hydrogen-containing gas is humidified in the middle of the hydrogen-containing gas inlet pipe 110 so that the humidified hydrogen-containing gas is supplied to the anode 102 of the electrolyte membrane-electrode assembly 120 via the anode-side separator 104. A humidifying tank 109 is arranged.

A hydrogen outlet tube 111 that discharges hydrogen generated by the cathode 103 from the cathode-side separator 105 is connected to the cathode terminal plate 107 that is arranged so as to be electrically connected to the cathode 103 via the cathode-side separator 105. Has been done.

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 terminal plate 106, and the negative electrode terminal of the voltage application unit 113 is the cathode terminal plate. Connected to 107.

Then, the current from the positive electrode terminal of the voltage application unit 113 flows from the anode terminal plate 106 in the order of the anode side separator 104, the anode 102, the electrolyte membrane 101, the cathode 103, the cathode side separator 105, and the cathode terminal plate 107. , Flows to the negative electrode terminal of the voltage application unit 113.

In this way, the electrochemical device 200 generates hydrogen at the cathode 103 from the hydrogen-containing gas supplied to the anode 102, and extracts high-purity hydrogen from the hydrogen outlet tube 111 (for example, Patent Document). 1).

Special Publication No. 62-59184

However, in the conventional configuration, the hydrogen in the hydrogen-containing gas supplied to the electrolyte membrane-electrode assembly 120 is insufficient for the magnitude of the current flowing through the electrolyte membrane-electrode assembly 120 of the electrochemical device 200. In the so-called electrochemical device 200, when hydrogen deficiency occurs, a reaction to generate hydrogen ions from hydrogen in the hydrogen-containing gas shown in (Chemical formula 1) occurs in the upstream part of the anode gas flow path, but the middle flow There is a shortage of hydrogen in the downstream area.

At this time, in the middle to downstream part of the anode gas flow path, instead of the reaction of generating hydrogen ions from hydrogen, hydrogen ions are generated from the catalyst-supported carbon of the anode and water shown in (Chemical formula 3) and (Chemical formula 4). An oxidative corrosion reaction occurs.

The oxidative corrosion reaction of the catalyst-supported carbon of this anode is concentrated only in the portion where hydrogen is deficient and water is present. Due to the local oxidative corrosion of the oxidatively corroded carbon, the resistance overvoltage increases due to the decrease in the conductive path of the catalyst layer, and the Pt supported on the oxidatively corroded carbon is missing to reduce the reaction area. The reaction overvoltage rises due to. As a result, there is a problem that the hydrogen purification efficiency of the electrochemical device is lowered.

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

The present invention solves the above-mentioned conventional problems, and is an electrochemical device that suppresses oxidative corrosion of the catalyst-supported carbon of the anode to prevent an increase in resistance overvoltage and an increase in reaction overvoltage even when a hydrogen-containing gas is deficient. It is an object of the present invention to provide a hydrogen generation system comprising.

In order to solve the above-mentioned conventional problems, the hydrogen generation system of the present invention comprises an electrolyte membrane, an anode arranged on one surface of the electrolyte membrane, and a cathode arranged on the other surface. -It has an electrode junction, an anode-side separator and a cathode-side separator arranged on both outer sides of the anode and the cathode, supplies a hydrogen-containing gas to the anode, and a current in a predetermined direction between the anode and the cathode. It is equipped with an electrochemical device that generates hydrogen at the cathode, a gas supply means that supplies hydrogen-containing gas to the anode, and a power supply for passing a current between the cathode and the cathode of the electrochemical device. The cathode side separator has a cathode gas flow path provided on the surface abutting the cathode and a cathode gas outlet communicating with the cathode gas flow path, and the electrochemical device stores water in the cathode gas flow path. In a hydrogen generation system that produces hydrogen in a state of being, the cathode is composed of at least an anode catalyst layer made of carbon carrying a catalyst, at least carbon for corrosion that does not carry a catalyst, and a carbon or non-carbon gas diffusion layer. The carbon for corrosion is characterized in that it is more easily oxidatively corroded than other carbons constituting the cathode. Further, the hydrogen generation system of the present invention is characterized in that the temperature of the cathode side separator is lower than the temperature of the anode side separator and that the cathode side separator has a water supply inlet for injecting water into the cathode gas flow path. It has the characteristics of either one of them.

With this configuration, when the hydrogen (hydrogen-containing gas) supplied to the anode is depleted, the hydrogen in the hydrogen-containing gas shown in (Chemical formula 1) is dissociated into hydrogen ions and electrons in the upstream part of the anode gas flow path. Happens. On the other hand, in the middle to the downstream part, hydrogen is insufficient and an oxidative corrosion reaction that generates hydrogen ions from carbon and water shown in (Chemical formula 3) and (Chemical formula 4) occurs.

The oxidative corrosion reaction of the carbons shown in (Chemical Formula 3) and (Chemical Formula 4) occurs with respect to the carbon that is most easily oxidatively corroded among the carbons present in the anode. The carbon present in the anode is the catalyst-supported carbon, the carbon constituting the gas diffusion layer when carbon is used as the material of the gas diffusion layer, and the carbon constituting the separator when carbon is used as the material of the separator. , And carbon for corrosion.

In this configuration, since the corrosive carbon is the material most easily oxidatively corroded, the corrosive carbon is used for the reaction, and the catalyst-supported carbon is not oxidatively corroded. Since the catalyst-supported carbon is not oxidatively corroded, it is possible to prevent the catalyst from being lost due to the disappearance of the supported carbon and to suppress a decrease in the reaction area.

Further, the carbon oxidative corrosion reaction shown in (Chemical 3) and (Chemical formula 4) requires water. In this configuration, water is stored in the gas flow path provided in the cathode side separator, and the water stored in the cathode gas flow path moves to the anode through the electrolyte membrane, and the water deficient in the anode can be supplemented.

This reduces the bias and deficiency of water in the anode, and can prevent the decrease in the conductive path of the catalyst layer caused by the oxidative corrosion reaction of carbon in the anode being locally concentrated and oxidatively corroded.

The hydrogen generation system of the present invention suppresses a decrease in the conductive path and a decrease in the reaction area of the catalyst layer caused by oxidative corrosion of the catalyst-supporting carbon of the anode when the hydrogen-containing gas is deficient, and increases the resistance overvoltage and the reaction overvoltage. And prevent. This makes it possible to provide a highly reliable hydrogen generation system capable of maintaining the hydrogen purification efficiency of the electrochemical device even when the hydrogen-containing gas is deficient.

Schematic diagram of the hydrogen generation system according to the first embodiment of the present invention. Schematic diagram of the hydrogen generation system according to the second embodiment of the present invention. Schematic diagram of the hydrogen generation system according to the third embodiment of the present invention. Schematic diagram of the hydrogen generation system according to the fourth embodiment of the present invention. Schematic diagram of the hydrogen generation system according to the fifth embodiment of the present invention. Schematic diagram of a conventional hydrogen generation system

The first invention comprises an electrolyte membrane-electrode junction composed of an electrolyte membrane, an anode arranged on one surface of the electrolyte membrane, and a cathode arranged on the other surface, and both outer sides of the anode and cathode. It has an anode-side separator and a cathode-side separator arranged in the cathode, and supplies hydrogen-containing gas to the cathode and passes a current in a predetermined direction between the anode and the cathode to generate hydrogen at the cathode. It comprises a chemical device, a gas supply means for supplying hydrogen-containing gas to the anode, and a power source for passing a current between the cathode and the cathode of the electrochemical device, and the cathode side separator is on the surface abutting the cathode. It has a provided cathode gas flow path and a cathode gas outlet that communicates with the cathode gas flow path, and the electrochemical device is a hydrogen generation system that generates hydrogen while water is stored in the cathode gas flow path. The cathode is composed of at least an anode catalyst layer made of carbon carrying a cathode, at least carbon for corrosion that does not carry a catalyst, and a carbon or non-carbon gas diffusion layer.
It is a hydrogen generation system characterized in that the carbon for corrosion is more easily oxidatively corroded than other carbons constituting the anode, and the temperature of the cathode side separator is lower than the temperature of the anode side separator. ..

As a result, when the hydrogen (hydrogen-containing gas) supplied to the anode is insufficient, the carbon for corrosion, which is the carbon most easily oxidatively corroded at the anode, is consumed instead of hydrogen, so that the catalyst-supported carbon is oxidatively corroded. This is suppressed, and the increase in reaction overvoltage, which consists of a decrease in the reaction area, is suppressed.

As for the water required for the carbon oxidative corrosion reaction, the water stored in the cathode gas flow path permeates the electrolyte membrane and moves to the anode to supply the water required for the carbon oxidative corrosion reaction. The reaction is not locally concentrated, and the increase in resistance overvoltage due to the decrease in the conductive path of the catalyst layer is suppressed.

Further, since the temperature of the cathode side separator is lower than the temperature of the anode side separator, the state of water at the cathode is a gas as compared with the case where the temperature of the cathode side separator is higher than the temperature of the anode side separator. It is more likely to become a liquid, and it is possible to prevent the gas from flowing out of the cathode gas flow path together with the generated gas, so that more water can be stored in the cathode gas flow path. Further, it becomes easy to permeate the electrolyte membrane and supply water to the anode, and the decrease of the conductive path of the catalyst layer can be suppressed without the oxidative corrosion reaction being locally concentrated. On the other hand, in the anode-side separator, the water state is more likely to be gas than the liquid, as compared with the case where the temperature of the anode-side separator is lower than the temperature of the cathode-side separator, and the anode gas flow path and the gas diffusion layer. By preventing the water from clogging, the hydrogen required for the hydrogen oxidation reaction shown in (Chemical formula 1) can be supplied to the anode without deficiency. Due to these actions, even if the hydrogen-containing gas supplied to the anode is insufficient, it is possible to suppress a decrease in the hydrogen purification efficiency of the electrochemical device.

The second invention comprises an electrolyte membrane-electrode junction composed of an electrolyte membrane, an anode arranged on one surface of the electrolyte membrane, and a cathode arranged on the other surface, and both outer sides of the anode and cathode. It has an anode-side separator and a cathode-side separator arranged in the cathode, and supplies hydrogen-containing gas to the cathode and passes a current in a predetermined direction between the anode and the cathode to generate hydrogen at the cathode. It comprises a chemical device, a gas supply means for supplying hydrogen-containing gas to the anode, and a power source for passing a current between the cathode and the cathode of the electrochemical device, and the cathode side separator is on the surface abutting the cathode. It has a provided cathode gas flow path and a cathode gas outlet that communicates with the cathode gas flow path, and the electrochemical device is a hydrogen generation system that generates hydrogen while water is stored in the cathode gas flow path. The cathode has at least an anode catalyst layer made of carbon carrying a catalyst, at least a corrosion carbon not supporting a catalyst, and a carbon or non-carbon gas diffusion layer, and the corrosion carbon constitutes an anode. It is more susceptible to oxidative corrosion than other carbons, and the cathode side separator is a hydrogen generation system characterized by having a water supply inlet for injecting water into the cathode gas flow path .

As a result, when the hydrogen (hydrogen-containing gas) supplied to the anode is insufficient, the carbon for corrosion, which is the carbon most easily oxidatively corroded at the anode, is consumed instead of hydrogen, so that the catalyst-supported carbon is oxidatively corroded. A reaction consisting of a decrease in the reaction area
The rise of overvoltage is suppressed.

As for the water required for the carbon oxidative corrosion reaction, the water stored in the cathode gas flow path permeates the electrolyte membrane and moves to the anode to supply the water required for the carbon oxidative corrosion reaction. The reaction is not locally concentrated, and the increase in resistance overvoltage due to the decrease in the conductive path of the catalyst layer is suppressed.

In addition, by injecting water into the cathode gas flow path from the water supply inlet, water can be more reliably stored in the cathode gas flow path, and it becomes easier to permeate the electrolyte membrane and supply water to the anode, resulting in an oxidative corrosion reaction. There is no local concentration, and an increase in resistance overvoltage due to a decrease in the conductive path of the catalyst layer can be suppressed.

Due to these actions, even if the hydrogen-containing gas supplied to the anode is insufficient, it is possible to suppress a decrease in the hydrogen purification efficiency of the electrochemical device.

The third invention is a hydrogen generation system, in particular, characterized in that the cathode gas outlet of the first invention or the second invention is arranged vertically upward from the lowermost end of the cathode gas flow path .

As a result, the water in the portion vertically lower than the cathode gas outlet in the cathode gas flow path is hard to flow out from the cathode gas outlet due to the action of gravity, so that water can be reliably stored in the cathode gas flow path. It is possible to easily permeate the electrolyte membrane and supply water to the anode, and it is possible to suppress an increase in resistance overvoltage due to a decrease in the conductive path of the catalyst layer without locally concentrating the oxidative corrosion reaction.

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

(Embodiment 1)
FIG. 1 shows a schematic diagram of a hydrogen generation system according to the first embodiment of the present invention.

As shown in FIG. 1, in the electrochemical device 10 used in the hydrogen generation system 50 of the present embodiment, the electrolyte membrane-electrode assembly 9 in which the electrolyte membrane 4 is sandwiched between the anode 5A and the cathode 5C is separated on the anode side. It is configured to be sandwiched between 1A and the cathode side separator 1C. Further, the electrochemical device 10 is arranged so that both main surfaces of the electrolyte membrane-electrode assembly 9 (electrolyte membrane 4) are parallel to the vertical direction.

The anode 5A is composed of an anode catalyst layer 3A, a corrosion carbon layer 13A and an anode gas diffusion layer 2A, and the cathode 5C is composed of a cathode catalyst layer 3C and a cathode gas diffusion layer 2C. The electrolyte membrane 4 is arranged between the anode 5A and the cathode 5C.

The anode catalyst layer 3A is arranged on one main surface of the electrolyte membrane 4. The cathode catalyst layer 3C is arranged on the other main surface of the electrolyte membrane 4. The corrosive carbon layer 13A is arranged on the main surface of the anode catalyst layer 3A that does not face the electrolyte membrane 4. The anode gas diffusion layer 2A is arranged on the main surface of the corrosive carbon layer 13A that does not face the anode catalyst layer 3A. The cathode gas diffusion layer 2C is arranged on the main surface of the cathode catalyst layer 3C that does not face the electrolyte membrane 4.

Here, as the electrolyte membrane 4, a perfluorocarbon sulfonic acid-based polymer electrolyte membrane having a sulfonic acid group is used. The anode catalyst layer 3A and the cathode catalyst layer 3C are formed by mixing carbon particles carrying platinum and ionomer and applying the mixture to the electrolyte membrane 4 or a transfer film for transferring the catalyst layer to the electrolyte membrane 4. Is used. Further, carbon felt is used for the anode gas diffusion layer 2A and the cathode gas diffusion layer 2C.

The corrosive carbon layer 13A has carbon and ionomer. The carbon used for the corrosive carbon layer 13A is composed of carbon that is more easily corroded than the platinum-supported carbon used for the anode catalyst layer 3A.

The susceptibility of carbon to corrosion can be determined by the degree of graphitization and the specific surface area. When carbon is heat-treated at high temperature, the degree of graphitization increases. The lower the degree of graphitization, the more functional groups that trigger oxidative corrosion. Further, carbon having a larger specific surface area is more likely to be oxidatively corroded because it has more functional groups per unit volume. Therefore, specifically, as the corrosive carbon, carbon having a lower degree of graphitization than the platinum-supported carbon used for the anode catalyst layer 3A is used.

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

The anode side separator 1A is provided with an anode gas inlet 11A, an anode gas 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 side separator 1A that comes into contact with the anode gas diffusion layer 2A (anode 5A), and the upstream end communicates with the anode gas inlet 11A and the downstream end communicates with the anode gas outlet 12A. Communicating.

The gas supply means 16 supplies hydrogen-containing gas to the anode gas inlet 11A via the gas supply pipe 15. The anode gas inlet 11A is a hydrogen-containing gas supply passage for supplying the hydrogen-containing gas to the anode 5A via the anode gas flow path 14A.

The anode gas outlet 12A is for discharging hydrogen-containing gas from the anode 5A to discharge the hydrogen-containing gas (hydrogen-containing gas not used for hydrogen generation at the cathode 5C) remaining in the anode 5A without penetrating the cathode 5C. It is a passage.

Further, the cathode side separator 1C is provided with a cathode gas outlet 12C and a cathode gas flow path 14C.

The cathode gas flow path 14C has a groove shape on the surface of the cathode side separator 1C that comes into contact with the cathode gas diffusion layer 2C (cathode 5C) so that hydrogen generated by the cathode 5C flows from bottom to top against gravity. It is formed and communicates with the cathode gas outlet 12C arranged vertically above the upper end portion (most downstream portion) of the cathode gas flow path 14C.

The cathode gas outlet 12C is a hydrogen discharge passage for discharging hydrogen that has permeated through the cathode 5C from the cathode 5C.

The power supply 17 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 a predetermined direction is a current in a direction flowing from the anode 5A of the electrochemical device 10 to the cathode 5C via the electrolyte membrane 4. The positive pole terminal of the power supply 17 is connected to the anode side separator 1A, and the negative pole terminal of the power supply 17 is connected to the cathode side separator 1C.

The gas supply means 16 supplies the humidified hydrogen-containing gas to the electrochemical device 10 from the anode gas inlet 11A. The gas supply means 16 uses a fuel reformer that produces hydrogen-containing gas from city gas by utilizing a reforming reaction.

The operation and operation of the hydrogen generation system 50 of the present embodiment configured as described above will be described below.

First, a case where a sufficient amount of hydrogen-containing gas is supplied to the anode 5A of the electrochemical device 10 with respect to the magnitude of the current flowing through the electrochemical device 10 will be described.

First, the hydrogen-containing gas humidified from the gas supply means 16 is supplied to the anode gas flow path 14A via the gas supply pipe 15 and the anode gas inlet 11A. The hydrogen-containing gas supplied by the gas supply means 16 to the anode 5A has a gas temperature of 70 ° C. and a relative humidity of 90%.

The hydrogen-containing gas supplied by the gas supply means 16 to the anode 5A has a carbon monoxide content of 0.00146%, a carbon dioxide content of 14.6%, and a hydrogen content of 58.4. %.

Next, the power source 17 causes a current of 90 A to flow between the anode 5A and the cathode 5C in the direction of flowing from the anode 5A to the cathode 5C via the electrolyte membrane 4.

Then, the amount of hydrogen-containing gas supplied from the gas supply means 16 to the electrochemical device 10 is adjusted so that the fuel utilization rate becomes 90%. Then, due to the reaction of (Chemical formula 1), hydrogen dissociates into hydrogen ions and electrons at the anode 5A, the hydrogen ions pass through the electrolyte membrane 4 and move to the cathode 5C side, and the electrons pass through the power source 17 to the cathode 5C. It moves, and by the reaction of (Chemical formula 2), hydrogen ions and electrons are combined at the cathode 5C to form hydrogen.

When hydrogen ions permeate through the electrolyte membrane 4, they move to the cathode 5C side with the water contained in the electrolyte membrane 4, and in order for hydrogen ions to move in the electrolyte membrane 4, the electrolyte membrane 4 moves water. Since it is essential to contain the hydrogen-containing gas, the hydrogen-containing gas supplied to the anode 5A is humidified and supplied as described above.

Of the hydrogen-containing gas supplied to the anode 5A, the hydrogen-containing gas that did not permeate through the cathode 5C and remained in the anode 5A (hydrogen-containing gas that was not used for hydrogen generation at the cathode 5C) became hydrogen-containing off-gas. Then, it is discharged from the anode gas outlet 12A.

The electrolyte membrane 4 contains a small amount of carbon monoxide and carbon dioxide from the cathode gas outlet 12C because the electrolyte membrane 4 made of a polymer permeates carbon monoxide and carbon dioxide, although the amount is small. In the present embodiment, a hydrogen-containing gas having a hydrogen purity of 99.97% is discharged.

Here, the hydrogen purification efficiency is calculated from the hydrogen gas flow rate generated in the cathode 5C, the current value instructed to the power supply 17, and the voltage value between the anode 5A and the cathode 5C of the electrochemical device 10 measured by the measuring instrument. ..

The hydrogen purification efficiency is expressed by the ratio of the energy of hydrogen obtained from the cathode 5C to the electric energy input to the power source 17.

The hydrogen gas flow rate (NL / s) generated at the cathode 5C is described below using the current value (A) and the return hydrogen gas flow rate that back-permeates the electrolyte membrane 4 from the cathode 5C to the anode 5A and returns. It can be represented by (Equation 1).

Here, the return hydrogen gas flow rate depends on the type, thickness, and water content of the electrolyte membrane 4, and the partial pressure of the hydrogen gas between the anode 5A and the cathode 5C. In the present embodiment, the return hydrogen gas flow rate is 0.00035 (NL / s), and the current value of the current flowing from the anode 5A to the cathode 5C via the electrolyte membrane 4 is 90 (A), so that hydrogen is used. The gas flow rate is 0.01010 (NL / s).

Therefore, the hydrogen energy obtained from the cathode 5C is the following (Equation 2) using the hydrogen gas flow rate (NL / s), 22.4 (NL / mol) and the high calorific value of hydrogen 285800 (J / mol). Can be represented.

Further, the electric energy to be input to the power source 17 can be calculated from the current value (A) and the voltage (V). In the present embodiment, the current value was 0.075 (V) when a current having a current value of 90 (A) was passed from the anode 5A to the cathode 5C via the electrolyte membrane 4. The hydrogen purification efficiency can be calculated by the following (Equation 3), which is 19.1 in the present embodiment.

Next, the behavior of the hydrogen generation system 50 when the hydrogen-containing gas is deficient will be described. As described above, a current with a current value of 90 (A) is passed from the anode 5A to the cathode 5C via the electrolyte membrane 4, and hydrogen-containing gas having a gas temperature of 70 ° C. and a relative humidity of 90% is used as fuel. When supplying to the anode 5A so that the ratio becomes 90%, the hydrogen-containing gas does not temporarily flow to the electrochemical device 10 in which the hydrogen-containing gas is shut off once every 10 seconds for 2 seconds and then flows again. Set aside time. This is done for 1 minute to create a state in which the hydrogen-containing gas is deficient.

When the hydrogen-containing gas is deficient, the hydrogen required for the reaction of (Chemical formula 2) is insufficient for the current 90A flowed by the power supply 17, and the anode 5A has carbon as shown in (Chemical formula 3) and (Chemical formula 4). An oxidative corrosion reaction occurs that produces hydrogen ions from water.

The carbon present in the anode 5A is platinum-supported carbon, corrosive carbon, carbon constituting the gas diffusion layer, and carbon constituting the anode side separator 1A. Among them, the corrosive carbon most easily oxidatively corroded is Used in the reaction and corroded.

In addition, water is also consumed in the reactions of (Chemical 3) and (Chemical formula 4). The water supplied as the humidifying gas of the anode 5A is necessary to wet the electrolyte membrane 4, the anode catalyst layer 3A, and the cathode catalyst layer 3C to facilitate the movement of hydrogen ions, so that more water is supplied. There is a need.

In the present embodiment, the cathode gas outlet 12C from which the hydrogen generated by the cathode 5C is discharged is arranged vertically above the upper end of the cathode 5C (cathode gas flow path 14C).

As a result, the water that has permeated through the electrolyte membrane 4 from the anode 5A can be stored up to the height of the cathode gas outlet 12C of the cathode gas flow path 14C. The water stored in the cathode gas flow path 14C constantly wets the electrolyte membrane 4 from the cathode 5C side, permeates the electrolyte membrane 4, and can supply water to the anode 5A as well.

After the operation in which the hydrogen-containing gas is deficient, when the operation is performed under the original operating conditions in which the hydrogen-containing gas is not deficient, the voltage between the anode 5A and the cathode 5C of the electrochemical device 10 is 0.076 (V). The hydrogen purification efficiency was 18.8, and even if the operation was performed in which the hydrogen-containing gas was deficient, almost no decrease in the hydrogen purification efficiency was observed.

As described above, in the hydrogen generation system 50 of the present embodiment, there is more oxidative corrosion between the anode catalyst layer 3A and the anode gas diffusion layer 2A than the carbon constituting the anode catalyst layer 3A and the anode gas diffusion layer 2A. Since the corrosive carbon layer 13A made of corrosive carbon that is easily corroded is provided, in the oxidative corrosion reaction of carbon when the hydrogen-containing gas supplied to the anode 5A is depleted, the carbon that is most easily oxidatively corroded in the anode 5A is for corrosion. Since the corrosive carbon of the carbon layer 13A is consumed instead of hydrogen, the catalyst-supported carbon is oxidatively corroded, the reaction area is reduced, and the reaction overvoltage is suppressed from rising.

Further, the hydrogen generation system 50 of the present embodiment is provided on the cathode side separator 1C, communicates with the cathode gas flow path 14C formed in a groove shape on the surface in contact with the cathode 5C, and permeates the cathode 5C. The cathode gas outlet 12C, which discharges water from the cathode 5C, is arranged vertically above the upper ends of the cathode 5C and the cathode gas flow path 14C, so that the electrochemical device 10 stores water in the cathode gas flow path 14C. It will generate hydrogen in the state of cathode.

Therefore, the water stored in the cathode gas flow path 14C permeates the electrolyte membrane 4 and moves to the anode 5A, so that the water required for the oxidative corrosion reaction of carbon can be supplied.

As a result, the oxidative corrosion reaction does not concentrate locally, and the increase in resistance overvoltage due to the decrease in the conductive path of the catalyst layer can be suppressed. From the above, even if a deficiency of the hydrogen-containing gas occurs, it is possible to suppress a decrease in the hydrogen purification efficiency of the electrochemical device 10.

In the present embodiment, the composition of the hydrogen-containing gas is carbon monoxide, carbon dioxide, and hydrogen, but the composition is not limited to this as long as it contains hydrogen.

In the present embodiment, the operating conditions when the hydrogen-containing gas is deficient are cut off once every 10 seconds for 2 seconds, but the cutoff time interval and the cutoff time are not limited to this. ..

(Embodiment 2)
FIG. 2 shows a schematic diagram of the hydrogen generation system according to the second embodiment of the present invention. In the hydrogen generation system 60 according to the second embodiment of the present invention, the position of the cathode gas outlet 12C of the hydrogen generation system 50 according to the first embodiment is lowered to the central position in the vertical direction of the cathode 5C. Other than this configuration, the configuration is the same as that of the hydrogen generation system 50 in the first embodiment, and duplicate description will be omitted.

The operation and operation of the hydrogen generation system 60 of the present embodiment configured as described above will be described.

In the hydrogen generation system 60 of the present embodiment, the position of the cathode gas outlet 12C of the electrochemical device 10 is arranged in the center of the cathode 5C in the vertical direction as shown in FIG. 2, so that the cathode gas flow path 14C is arranged. Water can be stored in the cathode gas flow path 14C from below in the vertical direction to the height of the cathode gas outlet 12C.

The water stored in the cathode gas flow path 14C permeates the electrolyte membrane 4 and moves to the anode 5A. In this way, the water required for the oxidative corrosion reaction of carbon is supplied from the cathode gas flow path 14C to the anode 5A via the electrolyte membrane 4, so that the oxidative corrosion reaction is suppressed from being locally concentrated and the anode catalyst layer. It is possible to suppress the decrease of the conductive path of 3A.

Since the electrolyte membrane 4 allows water to permeate well, it has an effect of supplying water to the anode 5A corresponding to the portion of the cathode gas flow path 14C where water is not stored.

First, the hydrogen purification efficiency when the hydrogen generation system 60 is operated by supplying a sufficient amount of hydrogen-containing gas to the anode 5A of the electrochemical device 10 with respect to the magnitude of the current flowing through the electrochemical device 10. To calculate.

The hydrogen-containing gas supplied by the gas supply means 16 to the anode 5A has a gas temperature of 70 ° C. and a relative humidity of 90%.

The hydrogen-containing gas has a carbon monoxide content of 0.00146%, a carbon dioxide content of 14.6%, and a hydrogen content of 58.4%.

Next, a current in the direction of flowing from the anode 5A to the cathode 5C via the electrolyte membrane 4 is passed between the anode 5A and the cathode 5C by the power supply 17 at a current value of 90 (A).

Then, the amount of hydrogen-containing gas supplied from the gas supply means 16 to the electrochemical device 10 is adjusted so that the fuel utilization rate becomes 90%.

At this time, the voltage between the anode 5A and the cathode 5C of the electrochemical device 10 is 0.73 (V), and the hydrogen purification efficiency is 19.6 from the amount of hydrogen produced (Equation 3).

Next, the behavior of the hydrogen generation system 60 when the hydrogen-containing gas is deficient will be described. As described above, a current having a current value of 90 (A) is passed from the anode 5A to the cathode 5C via the electrolyte membrane 4, and a hydrogen-containing gas having a gas temperature of 70 ° C. and a relative humidity of 90% is used as fuel. When the hydrogen-containing gas is flowing to the anode 5A so that the utilization rate is 90%, the hydrogen-containing gas is shut off once every 10 seconds for 2 seconds and then flowed again. Is provided. This is done for 1 minute to create a state in which the hydrogen-containing gas is deficient.

After the operation in which the hydrogen-containing gas is deficient, when the operation is performed under the original operating conditions in which the hydrogen-containing gas is not deficient, the voltage between the anode 5A and the cathode 5C of the electrochemical device 10 is 0.074 (V). The hydrogen purification efficiency was 19.3, and even if the operation was performed in which the hydrogen-containing gas was deficient, almost no decrease in the hydrogen purification efficiency was observed.

As described above, in the hydrogen generation system 60 of the present embodiment, the positions of the cathode gas outlet 12C of the electrochemical device 10 in the vertical direction with respect to the cathode 5C are different from those of the hydrogen generation system 50 of the first embodiment. In the hydrogen generation system 60 of the present embodiment, the cathode gas outlet 12C of the electrochemical device 10 is arranged at the center of the cathode 5C in the vertical direction.

As a result, the water stored up to the height of the cathode gas outlet 12C in the cathode gas flow path 14C permeates the electrolyte membrane 4 and is supplied to the anode 5A. Then, water permeates through the electrolyte membrane 4, and water can be supplied to the portion of the anode 5A facing the portion where water is not stored in the cathode gas flow path 14C.

On the other hand, since water is supplied to the anode 5A corresponding to the upstream of the anode gas flow path 14A by steam from the humidified anode gas, the probability of water shortage is low, and water is uniformly supplied over the entire surface of the anode 5A. It becomes a state.

Therefore, even if an oxidative corrosion reaction of carbon occurs when the hydrogen-containing gas supplied to the anode 5A is deficient, the oxidative corrosion reaction does not locally concentrate because there is no bias in water, and the conductive path of the anode catalyst layer 3A. It is possible to suppress an increase in resistance overvoltage, which is a decrease.

Further, in the carbon constituting the anode 5A, the corrosive carbon of the corrosive carbon layer 13A, which is most easily oxidatively corroded, is consumed instead of hydrogen, so that the catalyst-supported carbon is oxidatively corroded and the reaction area is reduced, resulting in a reaction. Suppresses the rise of overvoltage. From the above, even if a deficiency of the hydrogen-containing gas occurs, it is possible to suppress a decrease in the hydrogen purification efficiency of the electrochemical device 10.

In the present embodiment, the composition of the hydrogen-containing gas is carbon monoxide, carbon dioxide, and hydrogen, but the composition is not limited to this as long as it contains hydrogen.

In the present embodiment, the position of the cathode gas outlet 12C is set to the center in the vertical direction, but even if the position is not exactly the center and is slightly deviated from the center in the vertical direction, the position is higher than the center in the vertical direction. It may be on the upper side.

(Embodiment 3)
FIG. 3 shows a schematic diagram of the hydrogen generation system according to the third embodiment of the present invention.

In the hydrogen generation system 70 according to the third embodiment of the present invention, the anode 5A is vertically downward with respect to the electrolyte membrane 4 and the cathode 5C is the electrochemical device 10 of the hydrogen generation system 60 according to the second embodiment. It corresponds to the one installed so as to be on the upper side in the vertical direction.

In the hydrogen generation system 50 of the first embodiment and the hydrogen generation system 60 of the second embodiment, both main surfaces of the electrolyte membrane-electrode assembly 9 (electrolyte membrane 4) are electrochemically oriented so as to be parallel to the vertical direction. Although the device 10 is arranged, in the hydrogen generation system 70 of the third embodiment, both main surfaces of the electrolyte membrane-electrode assembly 9 (electrolyte membrane 4) are perpendicular to the vertical direction (both main surfaces are horizontal). At the same time, the electrochemical device 10 is arranged so that the cathode 5C is located on the upper side in the vertical direction of the anode 5A, and the cathode gas outlet 12C is on the upper side in the vertical direction with respect to the cathode 5C.

Other configurations are the same as those of the hydrogen generation system 60 of the second embodiment, and redundant description will be omitted.

The operation and operation of the hydrogen generation system 70 of the present embodiment configured as described above will be described.

In the hydrogen generation system 70, since the cathode gas outlet 12C is located above the cathode 5C in the vertical direction, water can be stored in all of the cathode gas flow paths 14C. The water stored in the cathode gas flow path 14C can constantly wet the electrolyte membrane 4 from the cathode 5C side, permeate the electrolyte membrane 4, and supply water to the anode 5A.

First, the hydrogen purification efficiency when the hydrogen generation system 70 is operating by supplying a sufficient amount of hydrogen-containing gas to the anode 5A of the electrochemical device 10 with respect to the magnitude of the current flowing through the electrochemical device 10. To calculate.

The hydrogen-containing gas supplied by the gas supply means 16 to the anode 5A has a gas temperature of 70 ° C. and a relative humidity of 90%.

The hydrogen-containing gas has a carbon monoxide content of 0.00146%, a carbon dioxide content of 14.6%, and a hydrogen content of 58.4%.

Next, a current in the direction of flowing from the anode 5A to the cathode 5C via the electrolyte membrane 4 is passed between the anode 5A and the cathode 5C by the power supply 17 at a current value of 90 (A).

Then, the amount of hydrogen-containing gas supplied from the gas supply means 16 to the electrochemical device 10 is adjusted so that the fuel utilization rate becomes 90%.

At this time, the voltage between the anode 5A and the cathode 5C of the electrochemical device 10 is 0.75 (V), and the hydrogen purification efficiency is 19.1 from (Equation 3).

Next, the behavior of the hydrogen generation system 60 when the hydrogen-containing gas is deficient will be described. As described above, a current with a current value of 90 (A) is passed from the anode 5A to the cathode 5C via the electrolyte membrane 4, and hydrogen-containing gas having a gas temperature of 70 ° C. and a relative humidity of 90% is used as fuel. When the hydrogen-containing gas is supplied to the anode 5A so that the ratio is 90%, the hydrogen-containing gas is shut off once every 10 seconds for 2 seconds and then flowed again. Is provided. This is done for 1 minute to create a state in which the hydrogen-containing gas is deficient.

After the operation in which the hydrogen-containing gas is deficient, when the operation is performed under the original operating conditions in which the hydrogen-containing gas is not deficient, the voltage between the anode 5A and the cathode 5C of the electrochemical device 10 is 0.076 (V). The hydrogen purification efficiency was 18.8, and even if the operation was performed in which the hydrogen-containing gas was deficient, almost no decrease in the hydrogen purification efficiency was observed.

As described above, in the hydrogen generation system 70 of the present embodiment, the orientation of the electrochemical device 10 is different from that of the hydrogen generation system 60 of the second embodiment, and the hydrogen generation system 70 of the present embodiment has a different orientation. The anode 5A is on the lower side in the vertical direction and the cathode 5C is on the upper side in the vertical direction with respect to the electrolyte membrane 4, and water can be stored in all of the cathode gas flow paths 14C.

With this configuration, the water stored in the cathode gas flow path 14C can be permeated into the electrolyte membrane 4 and supplied to the anode 5A, and the bias and deficiency of water in the anode 5A can be reduced.

Therefore, even if an oxidative corrosion reaction of carbon occurs when the hydrogen-containing gas supplied to the anode 5A is deficient, the oxidative corrosion reaction does not locally concentrate because there is no bias in water, and the conductive path of the anode catalyst layer 3A. It is possible to suppress an increase in resistance overvoltage, which is a decrease.

Further, in the anode 5A, the corrosive carbon of the corrosive carbon layer 13A, which is the carbon most easily oxidatively corroded, is consumed instead of hydrogen, so that the catalyst-supported carbon is oxidatively corroded and the reaction area is reduced, resulting in a reaction overvoltage. Suppresses the rise. From the above, even if a deficiency of the hydrogen-containing gas occurs, it is possible to suppress a decrease in the hydrogen purification efficiency of the electrochemical device.

In the present embodiment, the composition of the hydrogen-containing gas is carbon monoxide, carbon dioxide, and hydrogen, but the composition is not limited to this as long as it contains hydrogen.

In the present embodiment, the electrochemical device 10 is provided with the main surface of the electrolyte membrane 4 horizontally so that the cathode 5C is on the upper side in the vertical direction with respect to the electrolyte membrane 4, but the present invention is not limited to this. It does not matter if the main surface of the film 4 is not exactly horizontal and is slightly inclined with respect to the horizontal.

(Embodiment 4)
FIG. 4 shows a schematic diagram of the hydrogen generation system according to the fourth embodiment of the present invention.

In the hydrogen generation system 80 according to the fourth embodiment of the present invention, the anode heater 19A is provided outside the anode side separator 1A of the hydrogen generation system 50 according to the first embodiment, and the cathode heater 19C is provided outside the cathode side separator 1C. ing.

Further, the temperature controller 18 for controlling the anode heater 19A and the cathode heater 19C is provided. Other than this configuration, the configuration is the same as that of the first embodiment, and duplicate description will be omitted.

First, the hydrogen purification efficiency when the hydrogen generation system 80 is operating by supplying a sufficient amount of hydrogen-containing gas to the anode 5A of the electrochemical device 10 with respect to the magnitude of the current flowing through the electrochemical device 10. To calculate.

The hydrogen-containing gas supplied by the gas supply means 16 to the anode 5A has a gas temperature of 70 ° C. and a relative humidity of 90%. The hydrogen-containing gas has a carbon monoxide content of 0.00146%, a carbon dioxide content of 14.6%, and a hydrogen content of 58.4%.

The temperature of the anode heater 19A was set to 73 ° C., and the temperature of the cathode heater 19C was set to 65 ° C.

Next, a current in the direction of flowing from the anode 5A to the cathode 5C via the electrolyte membrane 4 is passed between the anode 5A and the cathode 5C by the power supply 17 at a current value of 90 (A).

Then, the amount of hydrogen-containing gas supplied from the gas supply means 16 to the electrochemical device 10 is adjusted so that the fuel utilization rate becomes 90%.

At this time, the voltage between the anode 5A and the cathode 5C of the electrochemical device 10 was 0.068 (V), so that the hydrogen purification efficiency was 21.1 from (Equation 3).

The operation and operation of the hydrogen generation system 80 of the present embodiment configured as described above will be described.

Since the cathode gas outlet 12C of the electrochemical device 10 is located above the cathode 5C (cathode gas flow path 14C) in the vertical direction, water can be stored in all of the cathode gas flow paths 14C.

Further, the temperature of the anode heater 19A is set to be higher than that of the cathode heater 19C (the temperature of the cathode heater 19C is set to be lower than that of the anode heater 19A).

As a result, on the cathode 5C side, the water vapor that has permeated the cathode 5C is dewed to change the state into liquid water, and it becomes easier to store water in the cathode gas flow path 14C, as compared with the case where such a temperature condition is not set. ..

Further, as compared with the case where such a temperature condition is not set, hydrogen as a fuel reaches the anode catalyst layer 3A by suppressing dew condensation of the hydrogen-containing gas humidified in the anode gas flow path 14A on the anode 5A side. This facilitates the process, and the effect of lowering the diffusion overvoltage due to the diffusion of the hydrogen-containing gas can be obtained.

Further, the water stored in the cathode gas flow path 14C can constantly wet the electrolyte membrane 4 from the cathode 5C side, pass through the electrolyte membrane 4, and supply water to the anode 5A.

Next, the behavior of the hydrogen generation system 80 when the hydrogen-containing gas is deficient will be described. As described above, a current with a current value of 90 (A) is passed from the anode 5A to the cathode 5C via the electrolyte membrane 4, and hydrogen-containing gas having a gas temperature of 70 ° C. and a relative humidity of 90% is used as fuel. When the hydrogen-containing gas is supplied to the anode 5A so that the ratio is 90%, the hydrogen-containing gas is shut off once every 10 seconds for 2 seconds and then flowed again. Is provided. This is done for 1 minute to create a state in which the hydrogen-containing gas is deficient.

After the operation in which the hydrogen-containing gas was deficient, when the operation was performed under the original operating conditions in which the hydrogen-containing gas was not deficient, the voltage between the anode 5A and the cathode 5C of the electrochemical device 10 was 0.069 (V). However, the hydrogen purification efficiency was 20.9, and even if the operation was performed in which the hydrogen-containing gas was deficient, almost no decrease in the hydrogen purification efficiency was observed.

As described above, in the present embodiment, the electrochemical device 10 is provided with a heater so that the temperature of the anode 5A can be controlled higher than that of the cathode 5C (the temperature of the cathode 5C is lower than that of the anode 5A). ..

As a result, it becomes easier to store water in the cathode gas flow path 14C as compared with the case where the temperature relationship between the anode 5A and the cathode 5C is not set so, so that the water stored in the cathode gas flow path 14C is transferred to the electrolyte membrane 4. It can be permeated and reliably supplied to the anode 5A.

Therefore, even if the oxidative corrosion reaction of carbon occurs when the hydrogen-containing gas supplied to the anode 5A is insufficient, the oxidative corrosion reaction of carbon is locally concentrated because the bias or shortage of water is unlikely to occur in the anode 5A. It is possible to suppress an increase in resistance overvoltage due to a decrease in the conductive path of the catalyst layer.

Further, in the anode 5A, the corrosive carbon of the corrosive carbon layer 13A, which is the carbon most easily oxidatively corroded, is consumed instead of hydrogen, so that the catalyst-supported carbon is oxidatively corroded and the reaction area is reduced, resulting in a reaction overvoltage. Suppresses the rise.

From the above, even if a deficiency of the hydrogen-containing gas occurs, it is possible to suppress a decrease in the hydrogen purification efficiency of the electrochemical device.

In the present embodiment, the composition of the hydrogen-containing gas is carbon monoxide, carbon dioxide, and hydrogen, but the composition is not limited to this as long as it contains hydrogen.

In the present embodiment, the heater is arranged outside each separator, but the heater may be provided inside the separator.

(Embodiment 5)
FIG. 5 shows a schematic diagram of the hydrogen generation system according to the fifth embodiment of the present invention.

The hydrogen generation system 90 according to the fifth embodiment of the present invention is provided with a cathode water inlet 11C communicating with the cathode gas flow path 14C on the lower side in the vertical direction of the cathode gas flow path 14C of the hydrogen generation system 50 of the first embodiment. The cathode water inlet 11C and the water supply means 20 are connected by a water supply pipe 21.

A water pump is used as the water supply means 20. Other than this configuration, the configuration is the same as that of the hydrogen generation system 50 of the first embodiment, and redundant description will be omitted.

First, as in the first embodiment, a sufficient amount of hydrogen-containing gas is supplied to the anode 5A of the electrochemical device 10 with respect to the magnitude of the current flowing through the electrochemical device 10, and the hydrogen generation system 90 operates. Calculate the hydrogen purification efficiency when doing.

The hydrogen-containing gas supplied by the gas supply means 16 to the anode 5A has a gas temperature of 70 ° C. and a relative humidity of 90%.

The hydrogen-containing gas has a carbon monoxide content of 0.00146%, a carbon dioxide content of 14.6%, and a hydrogen content of 58.4%.

Water is supplied from the water supply means 20 to the cathode gas flow path 14C via the water supply pipe 21 and the cathode water inlet 11C, and the water supply is stopped when the cathode gas outlet 12C overflows.

A current in the direction of flowing from the anode 5A to the cathode 5C via the electrolyte membrane 4 is passed between the anode 5A and the cathode 5C by the power supply 17 at a current value of 90 (A).

Then, the amount of hydrogen-containing gas supplied from the gas supply means 16 to the electrochemical device 10 is adjusted so that the fuel utilization rate becomes 90%.

At this time, the voltage between the anode 5A and the cathode 5C of the electrochemical device 10 is 0.079 (V), and the hydrogen purification efficiency is 18.1 from (Equation 3).

The operation and operation of the hydrogen generation system 90 of the present embodiment configured as described above will be described.

With this configuration, since the cathode gas outlet 12C is located on the upper side in the vertical direction with respect to the cathode 5C (cathode gas flow path 14C), water can be stored in all of the cathode gas flow paths 14C.

Further, by supplying water from the vertically lower side of the cathode gas flow path 14C by the water supply means 20 and the cathode water inlet 11C, the cathode gas flow path 14C is arbitrary regardless of the temperature of the electrochemical device 10 or the ambient temperature. The amount of water can be reliably stored.

Then, the water stored in the cathode gas flow path 14C can constantly wet the electrolyte membrane 4 from the cathode 5C side, pass through the electrolyte membrane 4, and supply water to the anode 5A.

Next, the behavior of the hydrogen generation system 60 when the hydrogen-containing gas is deficient will be described. As described above, a current having a current value of 90 (A) is passed from the anode 5A to the cathode 5C via the electrolyte membrane 4, and hydrogen-containing gas having a gas temperature of 70 ° C. and a relative humidity of 90% is used as fuel. When the rate is 90% and the current is flowing through the anode 5A, the hydrogen-containing gas is shut off once every 10 seconds for 2 seconds and then flowed again, so that the electrochemical device 10 is provided with a time during which the hydrogen-containing gas does not flow temporarily. This is done for 1 minute to create a state in which the hydrogen-containing gas is deficient.

After the operation in which the hydrogen-containing gas is deficient, when the operation is performed under the original operating conditions in which the hydrogen-containing gas is not deficient, the voltage between the anode 5A and the cathode 5C of the electrochemical device 10 is 0.080 (V). The hydrogen purification efficiency was 17.9, and even if the operation was performed in which the hydrogen-containing gas was deficient, almost no decrease in the hydrogen purification efficiency was observed.

As described above, in the present embodiment, the cathode water inlet 11C communicating with the cathode gas flow path 14C is provided on the lower side in the vertical direction of the cathode gas flow path 14C of the electrochemical device 10, and the cathode water inlet 11C is provided. By connecting the water supply means 20 with the water supply pipe 21, it is possible to reliably store water in the cathode gas flow path 14C and eliminate the bias or shortage of water in the anode 5A.

As a result, even if an oxidative corrosion reaction of carbon occurs when the hydrogen-containing gas supplied to the anode 5A is deficient, the oxidative corrosion reaction does not concentrate locally, and the resistance overvoltage increases due to the decrease in the conductive path of the anode catalyst layer 3A. Can be suppressed.

Further, when an oxidative corrosion reaction occurs, the corrosive carbon of the corrosive carbon layer 13A, which is the carbon most easily oxidatively corroded at the anode 5A, is consumed instead of hydrogen, so that the catalyst-supported carbon is oxidatively corroded and reacts. The area is reduced and the reaction overvoltage is suppressed from rising.

From the above, even if the hydrogen-containing gas supplied to the anode 5A is deficient, it is possible to suppress a decrease in the hydrogen purification efficiency of the electrochemical device 10.

In the present embodiment, the composition of the hydrogen-containing gas is carbon monoxide, carbon dioxide, and hydrogen, but the composition is not limited to this as long as it contains hydrogen.

In the present embodiment, a water pump is used as the water supply means 20, but the present invention is not limited to this as long as it can supply water.

As described above, the hydrogen generation system according to the present invention can suppress the decrease in the reaction area due to the lack of the catalyst caused by the oxidative corrosion of the catalyst-supported carbon of the anode when the deficiency of the hydrogen-containing gas occurs. Therefore, it is most suitable for a hydrogen generation system equipped with an electrochemical device that generates high-purity hydrogen from a hydrogen-containing gas using an electrolyte membrane-electrode assembly.

1A Cathode side separator 1C Cathode side separator 2A Cathode gas diffusion layer 2C Cathode gas diffusion layer 3A Cathode catalyst layer 3C Cathode catalyst layer 4 Electrolyte membrane 5A Cathode 5C Cathode 9 Electrolyte membrane-electrode assembly 10 Electrochemical device 11A Anodic gas inlet 11C Cathode Water inlet 12A Anodic gas outlet 12C Cathode gas outlet 13A Corrosion carbon layer 14A Anodic gas flow path 14C Cathode gas flow path 15 Gas supply piping 16 Gas supply means 17 Power supply 18 Temperature controller 19A Anodic heater 19C Cathode heater 20 Water supply means 21 Water supply piping 50 Hydrogen generation system 60 Hydrogen generation system 70 Hydrogen generation system 80 Hydrogen generation system 90 Hydrogen generation system

Claims (3)

An electrolyte membrane-electrode junction composed of an anode and an anode arranged on one surface of the electrolyte membrane and a cathode arranged on the other surface, and arranged on both outer sides of the anode and the cathode. It has an anode-side separator and a cathode-side separator, and supplies hydrogen-containing gas to the anode and causes a current in a predetermined direction to flow between the anode and the cathode to generate hydrogen at the cathode. With electrochemical devices,
A gas supply means for supplying the hydrogen-containing gas to the anode,
A power source for passing an electric current between the anode and the cathode of the electrochemical device is provided.
The cathode-side separator has a cathode gas flow path provided on a surface abutting the cathode and a cathode gas outlet communicating with the cathode gas flow path.
The electrochemical device is a hydrogen generation system that generates hydrogen in a state where water is stored in the cathode gas flow path.
The anode has at least an anode catalyst layer made of carbon carrying a catalyst, at least a corrosive carbon not supporting a catalyst, and a carbon or non-carbon gas diffusion layer.
A hydrogen generation system , wherein the corrosive carbon is more easily oxidatively corroded than other carbon constituting the anode, and the temperature of the cathode side separator is lower than the temperature of the anode side separator . An electrolyte membrane-electrode junction composed of an anode and an anode arranged on one surface of the electrolyte membrane and a cathode arranged on the other surface, and arranged on both outer sides of the anode and the cathode. It has an anode-side separator and a cathode-side separator, and supplies hydrogen-containing gas to the anode and causes a current in a predetermined direction to flow between the anode and the cathode to generate hydrogen at the cathode. With electrochemical devices,
A gas supply means for supplying the hydrogen-containing gas to the anode,
A power source for passing an electric current between the anode and the cathode of the electrochemical device is provided.
The cathode-side separator has a cathode gas flow path provided on a surface abutting the cathode and a cathode gas outlet communicating with the cathode gas flow path.
The electrochemical device is a hydrogen generation system that generates hydrogen in a state where water is stored in the cathode gas flow path.
The anode has at least an anode catalyst layer made of carbon carrying a catalyst, at least corrosive carbon not supporting a catalyst, and a carbon or non-carbon gas diffusion layer.
The corrosive carbon is more susceptible to oxidative corrosion than other carbons constituting the anode, and the cathode side separator has a water supply inlet for injecting water into the cathode gas flow path. .. The hydrogen generation system according to claim 1 or 2 , wherein the cathode gas outlet is arranged on the upper side in the vertical direction from the lowermost end of the cathode gas flow path.

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