JP3772260B2 - Hydrogen supply device using solid polymer water electrolyzer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water electrolyzer that electrolyzes water using a solid polymer electrolyte membrane and generates oxygen at an anode and hydrogen at a cathode, and more specifically, high-pressure hydrogen gas of 35 to 70 MPa, for example, at a hydrogen station for a fuel cell. The present invention relates to a hydrogen supply apparatus capable of supplying
[0002]
[Prior art]
A polymer electrolyte membrane that electrolyzes water, generates oxygen at the anode and hydrogen at the cathode, and a hydrogen gas / liquid that separates water and hydrogen generated at the cathode of the water electrolysis tank A hydrogen supply apparatus comprising a separator, an oxygen gas-liquid separator that separates oxygen and water generated at the anode of the water electrolysis tank, and an electrolyzed water circulation line that supplies water to the water electrolysis tank has been conventionally known. It has been.
[0003]
As shown in FIGS. 2 and 3, the polymer electrolyte water electrolyzer is composed of an anode main electrode (1) and a cathode main electrode (2) disposed at both ends, and these main electrodes (1) and (2). A plurality of unit cells (16) arranged in series between and a pair of end plates (13) sandwiching a combination of anode main electrode (1) -multiple unit cells (16) -cathode main electrode (2) from both sides And bolts (14) and nuts (15) that pass through the four corners of the pair of end plates (13) and tighten the anode main electrode (1), the plurality of unit cells (16), and the cathode main electrode (2) from both sides. ). One cell (16) consists of the anode side of the bipolar plate (9), the anode feeder (7), the electrode assembly film (3), the cathode feeder (8), and the adjacent bipolar plate (9). It is mainly configured from the cathode side. At the peripheral edge of each cell (16) is an O-ring that seals the inside and outside of the water electrolysis cell between the electrode assembly membrane (3) and the surface of the bipolar plate (9) on the cathode power supply (8) side. (17) is interposed.
[0004]
As shown in FIG. 3, in the water electrolysis tank (51), a water supply header (10) is formed at the center of the lower end portion, and a hydrogen header (11) and an oxygen header (12) are formed in parallel with the upper end portion. Is formed.
[0005]
In the above hydrogen supply device, heat is generated by the electrolytic reaction of the water electrolysis tank, and the exhaust heat is generated by the movement by the circulating water on the oxygen side and the latent heat of vaporization of the water vapor on the hydrogen side.
[0006]
In this apparatus, the internal pressure is maintained by an O-ring (17) provided on the outer periphery of the water electrolysis tank, and the pressure of the generated gas is less than 1.1 MPa (10 kg / cm ² G). ing.
[0007]
[Problems to be solved by the invention]
By the way, the use of hydrogen in fuel cells is progressing, and for that purpose, it is a problem to supply high-pressure hydrogen gas of 35 to 70 MPa at a hydrogen station for fuel cells.
[0008]
However, when water electrolysis is performed at a high pressure of about several tens of MPa using the conventional hydrogen supply device, the amount of water vapor generated on the hydrogen side is extremely reduced, and sufficient exhaust heat cannot be obtained. There has been a problem that the temperature of the electrolyte membrane locally rises above the heat-resistant temperature and the electrolyte membrane is damaged.
[0009]
Moreover, when water electrolysis is performed at a high pressure of about several tens of MPa using the conventional hydrogen supply device, there is a problem that the seal by the O-ring is broken. Therefore, in order to obtain high-pressure hydrogen gas, it is necessary to produce low-pressure hydrogen using a conventional hydrogen supply device and pressurize this with a gas pump (compressor). There is a problem that a device for pressurization becomes a large scale. Therefore, it is conceivable to install a water electrolysis tank in the pressure vessel (see JP-A-6-33283), but the point that can handle a high pressure of about several tens of MPa and the structure of the pressure vessel are as simple and small in capacity as possible. Satisfactory things have not been obtained.
[0010]
It is an object of the present invention to provide a hydrogen supply device using a solid polymer type water electrolysis tank that prevents the electrolyte membrane from being damaged even when water electrolysis is performed at a high pressure of about several tens of MPa. .
[0011]
Furthermore, the present invention is a solid polymer type that has pressure resistance even when water electrolysis is performed at a high pressure of about several tens of MPa, and can make the structure of the pressure vessel as simple and small in capacity as possible. It is an object to provide a hydrogen supply device using a water electrolysis tank.
[0012]
[Means for Solving the Problems]
A hydrogen supply apparatus using the solid polymer type water electrolyzer of the present invention comprises a solid polymer type water electrolyzer that electrolyzes water using a polymer electrolyte membrane, generates oxygen at the anode and hydrogen at the cathode, A hydrogen gas-liquid separator that separates hydrogen and water generated at the cathode of the water electrolysis tank, an oxygen gas-liquid separator that separates oxygen and water generated at the anode of the water electrolysis tank, and water to the water electrolysis tank In a hydrogen supply device provided with an electrolyzed water circulation line to be supplied, a pressure vessel for storing the water electrolyzer so that the gap with the water electrolyzer is filled with water, and the water in the pressure vessel was taken out and processed. A cooling water circulation line that is later returned to the container is further provided, and a rectifying plate is provided in the water filling gap of the pressure container .
[0013]
In the hydrogen supply apparatus using the solid polymer type water electrolyzer of the present invention, the differential pressure for controlling the water circulation amount of the cooling water circulation line so that the differential pressure between the inside of the electrolyzer and the water filling part of the pressure vessel becomes a predetermined value. It is preferable to further include a control line. In this case, the differential pressure control line includes the pressure on the pressure vessel side of the cooling water circulation line = the pressure of the cooling water supplied to the pressure vessel (corresponding to the pressure outside the water electrolyzer) and the hydrogen gas / liquid separator or oxygen gas / liquid. The difference from the pressure of the separator (corresponding to the pressure inside the water electrolyzer) is controlled. Then, the water electrolysis tank is maintained at a positive internal pressure so that the pressure outside the water electrolysis tank is lower by several K to 10K than the pressure inside the water electrolysis tank.
[0014]
Integer Nagareban is for cooling water to impinge uniformly in water electrolyser, the shape, for example, but are porous plate type, but is not particularly limited.
[0015]
Furthermore, it is preferable that a deionization device comprising an RO membrane or an ion exchange membrane is provided in the cooling water circulation line. The cooling water does not have to be pure water as much as electrolyzed water, and is deionized water that does not cause electrical corrosion between the material of the outer periphery of the water electrolysis tank and the material of the liquid container of the pressure vessel. Since it is good, sufficient water quality can be ensured even with an RO membrane.
[0016]
In the case where the differential pressure control line is provided, the water electrolysis tank may be provided with a pressurizing device for tightening the tank with a predetermined tightening force. The electrode assembly film, the power feeder and the bipolar plate of the water electrolysis tank need to be tightened with an appropriate tightening force in order to conduct electricity uniformly over the entire surface. In the case where a differential pressure control line is provided, the pressure difference between the inside and outside of the water electrolyzer is kept constant even when the pressure of the gas to be produced is high. Can be set.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be specifically described based on examples. In the following description, the left and right refer to the left and right in the figure.
[0018]
In FIG. 1, a hydrogen supply apparatus using a solid polymer type water electrolyzer uses a polymer electrolyte membrane to electrolyze water, and generates oxygen at the anode and hydrogen at the cathode, respectively. (51), a pressure vessel (21) for containing the water electrolyzer (51), a hydrogen line (22) extending from the hydrogen discharge port of the water electrolyzer (51) through the right side wall of the pressure vessel (21), A hydrogen gas-liquid separator (23) provided in the hydrogen line (22) for separating hydrogen and water generated at the cathode of the water electrolyzer (51) and a pressure from the oxygen outlet of the water electrolyzer (51) An oxygen line (24) extending through the top wall of the vessel (21), an oxygen gas-liquid separator (25) for separating oxygen and water generated at the anode of the water electrolysis tank (51), and a pressure vessel ( An electrolyzed water circulation line (26) passing through the right side wall of 21) and leading to the feed header of the water electrolysis tank (51), and a cooling water circulation line (27) extending through the bottom wall of the pressure vessel (21), Electrolyzer (51) and pressure capacity A differential pressure control line (28) for controlling the water circulation amount of the cooling water circulation line (27) so that the differential pressure with respect to (21) becomes a predetermined value, and a pure water for storing pure water used in the water electrolysis tank (51). The water tank (29), the pure water introduction line (30) connecting the pure water tank (29) and the oxygen gas / liquid separator (25), the gas phase portion of the hydrogen gas / liquid separator (23) and the oxygen gas A gas pressure equalization line line (31) connecting the gas phase part of the liquid separator (25) and a DC power source (not shown) connected to the water electrolysis tank (51) are provided.
[0019]
The water electrolyzer (51) is the same as the conventional one shown in FIGS. 2 and 3, and the right end plate (13) is connected to the right wall of the pressure vessel (21) via the support plate (32). By being fixed, it is held in the pressure vessel (21). The gap between the pressure vessel (21) and the water electrolyzer (51) is filled with pure water, and a porous plate type rectifier plate (33) is inserted in the upper and lower water filling gaps of the pressure vessel (21). Each is provided. The support plate (32) is also provided with a plurality of holes for allowing cooling water to pass therethrough. A pressurizing device (34) for fastening the water electrolyzer (51) with a predetermined fastening force is also attached to the support plate (32).
[0020]
The hydrogen containing water taken out in the hydrogen line (22) is separated into hydrogen and pure water by the hydrogen gas-liquid separator (23), and the separated hydrogen is supplied to the hydrogen pressure regulating valve in the hydrogen line (22). Supplied to the outside at the pressure set in (35). The pure water separated by the hydrogen gas / liquid separator (23) is sent to the oxygen gas / liquid separator (25).
[0021]
The oxygen separated by the oxygen gas-liquid separator (25) is supplied to the outside at the pressure set in the oxygen pressure regulating valve (36). The pure water separated by the oxygen gas / liquid separator (25) passes through the piping (26a) on the oxygen gas / liquid separator side, and then is supplied to the water electrolysis tank (51) by the electrolyzed water circulation line (26). The water in the pure water tank (29) is sent to the oxygen gas-liquid separator (25) by the water supply pump (37) provided in the pure water introduction line (30), and the oxygen gas-liquid separator (25) Is supplied to the pipe (26a) on the oxygen gas-liquid separator side of the electrolyzed water circulation line (26). A circulating pump (38) is provided in the electrolyzed water circulation line (26).
[0022]
One end of the cooling water circulation line (27) is connected to a cooling water outlet provided on the right side wall of the pressure vessel (21), and the other end of the cooling water inlet () provided on the left end portion of the bottom wall of the pressure vessel (21). It is connected to the. The cooling water circulation line (27) includes a check valve (39), a cooler (40), a cooling water tank (41), a circulation pump (42), a deionization device (43) composed of an RO membrane, a check valve ( 44) and a pressure regulating valve (45) are provided in this order from the side close to the cooling water outlet of the pressure vessel (21).
[0023]
The differential pressure control line (28) has one end connected to the cooling water inlet of the cooling water circulation line (27) and the other end connected to the oxygen gas / liquid separator (25) (or hydrogen gas / liquid separator (23)). At the same time, the pressure regulating valve (45) of the cooling water circulation line (27) is controlled by the differential pressure ΔP0 between both ends.
[0024]
According to the hydrogen supply device using this polymer electrolyte water electrolyzer, water for electrolysis is pressurized and supplied to the feed header (10) of the water electrolyzer (51) by the electrolyzed water circulation line (26). (10) is led into each unit cell (16) and electrolyzed on the surface of the electrode assembly film (3), and oxygen is generated on the anode side and hydrogen is generated on the cathode side. The generated oxygen and hydrogen respectively reach the anode side and the cathode side of the bipolar plate (9) through the porous power feeders (7) and (8), and further the gas flow path provided in the bipolar plate (9) The water reaches the upper part of the water electrolysis tank (51), and is discharged through the oxygen header (11) and the hydrogen header (12) above the water electrolysis tank (51).
[0025]
Oxygen generated at the anode of the water electrolysis tank (51) is sent to the oxygen gas-liquid separator (25), and hydrogen generated at the cathode is sent to the hydrogen gas-liquid separator (23). At this time, most of the water coming out of the water electrolysis tank (51) is sent to the oxygen side. The water separated by the hydrogen gas-liquid separator (23) is sent to the oxygen gas-liquid separator (25), and is sent to the electrolyzed water circulation line (26) together with the newly supplied pure water, and the circulation pump (38 ) Is supplied again as pure water for electrolysis directly to the water electrolysis tank (51) (apart from the cooling water introduced into the pressure vessel (21)). Pure water is supplied to the water electrolyzer (51) by separating the pure water into oxygen gas and liquid using the water supply pump (37) according to the preset value of the oxygen gas and liquid separator (25). This is done by supplying to the vessel (25). In this way, pure water for electrolysis pressurized to a pressure commensurate with the desired pressure (a pressure allowing for the pressure loss in the water electrolysis tank (51) and the piping) is supplied to the water electrolysis tank (51). The oxygen separated by the oxygen gas-liquid separator (25) is supplied to the outside based on the set pressure of the oxygen pressure regulating valve (36), and the hydrogen generated at the cathode is set by the hydrogen pressure regulating valve (35). It is supplied to the outside based on the pressure. The hydrogen pressure regulating valve (35) is set so as to obtain a high pressure hydrogen gas of 35 to 70 MPa.
[0026]
The cooling water in the pressure vessel (21) is extracted from the cooling water outlet side of the cooling water circulation line (27), cooled by the cooler (40), and stored in the cooling water tank (41). Then, the water in the cooling water tank (41) is forcibly sent into the pressure vessel (21) by the circulation pump (42), so that the cooling water having a flow rate higher than a predetermined level flows into the pressure vessel (21). It is. This cooling water flows again into the cooling water outlet side of the cooling water circulation line (27) after the flow direction and the residence time are adjusted by the rectifying plate (33). Thus, the cooling water for cooling the electrolytic cell (51) is circulated.
[0027]
The cooling water supplied to the pressure vessel (21) is passed through a deionization device (43) made of an RO membrane, so that the deionized water has a degree that does not corrode the electrolytic cell (51) and the pressure vessel (21). Is done.
[0028]
The electrolytic reaction in the water electrolyzer (51) is an exothermic reaction, and its exhaust heat is transferred by circulating water on the oxygen side, latent heat of vaporization of water vapor on the hydrogen side, and heat transfer to the cooling water flowing through the pressure vessel (21). Has been done by. When water electrolysis is performed at a high pressure, the amount of water vapor generated on the hydrogen side is drastically reduced, but the heat exhausted by the latent heat of vaporization of this water vapor is exhausted by heat transfer to the cooling water flowing in the pressure vessel (21). Is compensated by Thus, even when high-pressure hydrogen gas is generated, the electrode assembly membrane (electrolyte membrane) (3) is prevented from being damaged by heat.
[0029]
When operating this hydrogen supply device, the differential pressure control line (28) detects the difference ΔP0 between the pressure near the cooling water inlet of the cooling water circulation line (27) and the pressure of the hydrogen gas-liquid separator (23). The pressure regulating valve (45) for determining the circulation amount of the cooling water circulation line (27) is controlled. At this time, the inside of the electrolytic cell (51) is controlled to be a slightly positive pressure compared with the pressure of the water filling part (that is, the outside of the water electrolytic cell), and thereby, the O provided in the electrolytic cell (51) is controlled. Damage to the ring (17) is prevented.
[0030]
【The invention's effect】
According to the present invention, the gap between the water electrolysis tank includes a pressure vessel to contain the water electrolyzer as filled with water, the water filling the gap of the pressure vessel, since the rectifying plates are provided, the cooling Water hits the water electrolysis tank uniformly, and the water filled in the gap with the water electrolysis tank can apply pressure to the water electrolysis tank and ensure the pressure resistance of the pressure vessel. In addition, since it further includes a cooling water circulation line that takes out the water in the pressure vessel to the outside and treats it into the vessel, the electrolytic cell is efficiently cooled by the cooling water having a flow rate of a predetermined value or more. The temperature of the electrolyte membrane is suppressed from being locally higher than the heat-resistant temperature, and even when water electrolysis is performed at a high pressure of about several tens of MPa, the electrolyte membrane is prevented from being damaged.
[0031]
Moreover, in the case of further comprising a differential pressure control line for controlling the water circulation amount of the cooling water circulation line so that the differential pressure between the inside of the electrolytic cell and the water filling part of the pressure vessel becomes a predetermined value, the inside of the electrolytic cell is filled with water. It is possible to control the pressure so as to be slightly positive compared with the pressure of the portion, and thereby, damage to the O-ring provided in the electrolytic cell is prevented.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a hydrogen supply apparatus according to the present invention.
FIG. 2 is an exploded perspective view showing a polymer electrolyte water electrolyzer used in the present invention.
FIG. 3 is a vertical sectional view of the same.
[Explanation of symbols]
(21): Pressure vessel
(23): Hydrogen gas-liquid separator
(25): Oxygen gas-liquid separator
(26): Electrolyzed water circulation line
(27): Cooling water circulation line
(28): Differential pressure control line
(33): Rectifying plate
(34): Pressurizing device
(43): Deionizer
(51): Solid polymer water electrolyzer

Claims (5)

A polymer electrolyte membrane that electrolyzes water, generates oxygen at the anode and hydrogen at the cathode, and a hydrogen gas / liquid that separates water and hydrogen generated at the cathode of the water electrolysis tank In a hydrogen supply apparatus comprising a separator, an oxygen gas-liquid separator that separates oxygen and water generated at the anode of the water electrolysis tank, and an electrolyzed water circulation line that supplies water to the water electrolysis tank, the water electrolysis tank A pressure vessel that houses the water electrolyzer so that the gap between the pressure vessel and the water is filled with water, and a cooling water circulation line that takes out the water in the pressure vessel to the outside and treats it, and returns it to the vessel. A hydrogen supply device using a solid polymer type water electrolysis tank, characterized in that a rectifying plate is provided in the water filling gap .   The pressure difference control line which controls the amount of water circulation of a cooling water circulation line is further provided so that the differential pressure of the inside of a water electrolysis tank and the water filling part of a pressure vessel may become a predetermined value, The 1st characterized by the above-mentioned. Hydrogen supply device using solid polymer type water electrolyzer.   3. The polymer electrolyte water electrolysis according to claim 2, wherein the differential pressure control line controls the difference between the pressure on the pressure vessel side of the cooling water circulation line and the pressure of the hydrogen gas-liquid separator or oxygen gas-liquid separator. Hydrogen supply device using a tank. The hydrogen supply device using the solid polymer water electrolyzer according to any one of claims 1 to 3 , wherein a deionization device comprising an RO membrane or an ion exchange membrane is provided in the cooling water circulation line. The hydrogen supply apparatus using the polymer electrolyte water electrolyzer according to any one of claims 2 to 4 , wherein the water electrolyzer is provided with a pressurizing device for tightening the tank with a predetermined tightening force.

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