JP2017002344A - Gas generation device and gas generation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas generation device capable of removing air dissolved in water, before water electrolysis reaction and capturing high purity hydrogen and oxygen.SOLUTION: A gas generation method and a gas generation device are configured to: before water electrolysis reaction 8, heat pure water to optimal temperature of the water electrolysis reaction; then decompress an air phase contacting the pure water; thereby collect air dissolved in the pure water into capture parts 31a, 31b; and block the air capture parts 31a, 31b from the pure water. Thereby the pure water becomes in a sealed state of not contacting any gas, and electrolysis is started.SELECTED DRAWING: Figure 2

Description

The present invention relates to a gas generator and a gas generation method. In particular, the present invention relates to an apparatus for generating hydrogen or oxygen by electrolysis of water, a method for generating hydrogen, or oxygen.

  In devices that use hydrogen, such as semiconductor cleaning processes, devices that use oxygen, such as medical equipment and welding machines, and devices that use both hydrogen and oxygen, such as fuel cells, impure gases other than hydrogen and oxygen are present. It must be free of contamination.

  That is, the purity of hydrogen and oxygen is required to be extremely high. For this reason, in the conventional gas production | generation apparatus, in order to raise the purity of hydrogen and oxygen, various devices have been made | formed.

  That is, what inhibits the high purity of hydrogen and oxygen generated by water electrolysis is component gas of air such as nitrogen, oxygen, argon and carbon dioxide dissolved in pure water as a raw material of hydrogen and oxygen. .

  Therefore, after hydrogen and oxygen are generated by water electrolysis, a method of removing these mixed gases is common. For example, a method of arranging one or more adsorption-type removal devices for each mixed gas is known.

  However, in such a method, the removal device becomes large and needs to be frequently replaced. For this reason, it has become an obstacle to lower the production cost of hydrogen and oxygen. Thus, a method has been proposed in which oxygen is blown into pure water to be subjected to water electrolysis in advance, and a gas other than oxygen dissolved in the pure water is expelled into the atmosphere, followed by water electrolysis (Patent Document 1). .

  By this method, pure water in which only oxygen is dissolved and other gases are not dissolved is electrolyzed to generate hydrogen containing only oxygen and water vapor on the negative electrode side, and oxygen and water vapor are removed from this mixed gas. High purity hydrogen can be obtained.

  With reference to FIG. 1, a gas generator 1 disclosed in Patent Document 1 will be described. Pure water is supplied to the storage tank 3 from a pure water source 2 connected to a pure water production apparatus (not shown). Next, pure water is sent from the storage tank 3 to the oxygen-side gas-liquid separator 5 by the pump 4. Further, it is sent by the pump 6 to the oxygen side flow path of the electrolytic cell 8 partitioned by the electrolyte membrane 7. When a voltage is applied to the electrolysis cell 8 by the power supply device 9, a water electrolysis reaction of pure water occurs in the electrolysis cell 8.

  At this time, oxygen is generated in flowing pure water in the oxygen-side flow path, and is sent to the upper gas phase section 11 of the oxygen-side gas-liquid separator 5 through the pipe 10 together with the pure water. In the upper gas phase section 11 of the oxygen-side gas-liquid separator 5, gaseous oxygen and liquid pure water are separated. Of these, the pure water merges with the pure water in the lower liquid phase portion 12 of the oxygen-side gas-liquid separator 5 and is sent again to the electrolysis cell 8 by the pump 6.

  Part of the gaseous oxygen is sent directly to the oxygen storage tank 14 through the pipe 13. The remaining gaseous oxygen passes through the pipe 15 and is sent to the ejection port 17 in the lower liquid phase part 16 of the storage tank 3. The gaseous oxygen ejected from the ejection port 17 rises in the pure water of the lower liquid phase part 16 of the storage tank 3, reaches the upper gas phase part 18 of the storage tank 3, and further passes through the pipe 19 to the oxygen side. It is sent to the storage tank 14. In the storage tank 3, oxygen blown into the lower liquid phase portion 16 is dissolved in pure water while rising in the lower liquid phase portion 16 by buoyancy, that is, Gases other than oxygen such as nitrogen, argon and carbon dioxide are expelled from the pure water.

  By this action, the pure water in the storage tank 3 is in a state where the dissolved gas other than oxygen is in a very low concentration along with the elapsed time of the water electrolysis reaction. When such pure water is sent to the oxygen side of the electrolytic cell 8, hydrogen as a gas generated by the water electrolysis reaction on the hydrogen side of the electrolyte membrane 7 and unpermeated through the electrolyte membrane 7 from the oxygen side to the hydrogen side. The reaction pure water is mixed. This mixture of hydrogen and pure water is sent from the hydrogen flow path of the electrolysis cell 8 through the pipe 20 to the hydrogen side gas-liquid separator 21. Among these, liquid pure water is dropped from the upper gas phase portion 11 of the hydrogen-side gas-liquid separator 21 to the pure water in the lower liquid phase portion 12, and is further returned to the storage tank 3 through the pipe 22.

  The gaseous hydrogen is sent to the deoxygenation column 24 and the dehydration column 25 through the pipe 23, where a trace amount of oxygen and water vapor contained in the hydrogen is removed, and then sent to the hydrogen-side storage tank 26. According to such a gas generator 1 of Patent Document 1, it is reported that 99.9999% of hydrogen can be obtained.

JP 58-189383 A

However, when hydrogen or oxygen generated by the gas generator 1 of Patent Document 1 as described above is supplied to a fuel cell to generate power, there are the following problems.
(1) At the initial stage of the water electrolysis reaction of the electrolytic cell 8, the oxygen side storage tank 14, the pipe 13, the pipe 15, the pipe 19, the upper gas phase part 18 of the storage tank 3, and the oxygen gas / liquid separator 5 Air remains in the phase portion 11. Since these residual air is stored in the oxygen side storage tank 14 together with oxygen, the oxygen concentration in the oxygen side storage tank 14 decreases. Therefore, when the oxygen in the oxygen-side storage tank 14 is supplied to the fuel cell and power generation is performed, the output voltage of the fuel cell is reduced as compared with the case where pure oxygen is supplied.

  (2) At the initial stage of the water electrolysis reaction of the electrolysis cell 8, since air remains in the pipe 10, the upper gas phase portion 11 of the oxygen-side gas-liquid separation device 5, and the pipe 15, it is stored from the electrolysis cell 8. The oxygen concentration supplied to the lower liquid phase part 16 of the tank 3 is in a low state. Therefore, the air component other than oxygen in the pure water, that is, nitrogen, argon, carbon dioxide, etc., is not sufficiently driven out by oxygen in the lower liquid phase part 16, and nitrogen, argon, carbon dioxide, etc. are electrolyzed together with pure water. It is supplied to the cell 8. When such pure water is supplied to the electrolysis cell 8, unreacted pure water that permeates the electrolyte membrane 7 appears on the hydrogen side, and the concentration of hydrogen generated by the water electrolysis reaction decreases. Accordingly, when such hydrogen is supplied to the fuel cell to generate power, the output voltage of the fuel cell is lower than when pure hydrogen is supplied.

  (3) A column for removing mixed gas compared to a method in which a special removal column is provided for each mixed gas such as nitrogen, argon, carbon dioxide, etc. after hydrogen or oxygen is generated by water electrolysis. Is only one type of deoxygenation column 24. However, in order to continue high-purity hydrogen collection by a long-time water electrolysis reaction, it is necessary to frequently replace the expensive deoxygenation column 24, which is an obstacle to lowering the production cost of hydrogen.

  Therefore, the object of the present invention is to provide high-concentration hydrogen that does not contain any gas other than water vapor and oxygen, and water vapor and hydrogen, in each of the oxygen or hydrogen storage tanks from immediately after the start of the water electrolysis reaction to the end of the reaction. And a gas generation method capable of storing oxygen and oxygen.

  In order to solve the above problems, an electrolysis cell that electrolyzes water to generate hydrogen and oxygen, an air collecting device connected to the electrolysis cell, and hydrogen or oxygen generated from the electrolysis cell are separated from water. A gas generator including a gas-liquid separator to be collected, a buffer cylinder connected to an electrolysis cell, and a storage tank for storing hydrogen or oxygen is used.

  An introduction step of introducing water into each of the devices connected to the electrolysis cell, the air collection unit, and the gas-liquid separation unit, and an air collection step of heating the water and collecting the gas in the water with the air collection device A gas generation step of decomposing water in an electrolysis cell to generate hydrogen or oxygen; a separation step of separating the generated hydrogen or oxygen from water by a gas-liquid separator; and hydrogen or And a storage process for collecting and storing oxygen in a storage tank.

  According to the present invention, pure water is heated to the optimum temperature for the water electrolysis reaction in advance of the water electrolysis reaction, and the air dissolved in the pure water is reduced by reducing the air phase in contact with the pure water. It can be manifested in the air collection part.

  Further, by shutting off the air collecting part from pure water, the pure water can be in a sealed state where it does not come into contact with any gas.

  Thereafter, since the water electrolysis reaction is started, it does not come into contact with a gas other than hydrogen or oxygen to be collected even during the water electrolysis reaction. Therefore, from the start of the water electrolysis reaction to the end of the reaction, it is always possible to store high concentrations of hydrogen and oxygen that do not contain any gas other than water vapor and hydrogen, and water vapor and oxygen.

Schematic diagram of water electrolysis hydrogen oxygen generator of Patent Document 1 Schematic diagram of water electrolysis hydrogen oxygen generator of Example 1 (A)-(f) Sectional drawing which shows the state transition in the water electrolysis hydrogen oxygen generator of an Example (A)-(g) Sectional drawing which shows the state transition in the water electrolysis hydrogen oxygen generator of an Example (A)-(c) Sectional drawing which shows the state transition in the water electrolysis hydrogen oxygen generator of an Example Schematic diagram of fuel cell stack evaluation system

Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment 1)
FIG. 2 is a schematic diagram of the water electrolysis hydrogen oxygen generator 27 in the first embodiment.

<Overall configuration>
In FIG. 2, the water electrolysis hydrogen oxygen generator 27 in Embodiment 1 mainly includes an electrolysis cell 8, gas-liquid separators 28a and 28b, storage tanks 29a and 29b, buffer cylinders 30a and 30b, air It is comprised from the collection parts 31a and 31b and the pressure reduction cylinders 32a and 32b.

<Overall process>
In FIG. 2, the pure water injected from the storage tanks 29a and 29b reaches the air collecting parts 31a and 31b through the gas-liquid separators 28a and 28b and the pipes 33a and 33b.

  Thereafter, the pure water is returned to the gas-liquid separators 28 a and 28 b through the electrolytic cell 8 and the pipes 34 a and 34 b by the action of the pump 6.

  In the pipes 33a and 33b, buffer cylinders 30a and 30b are installed at positions in contact with the pipe side surfaces.

  Further, decompression cylinders 32a and 32b are installed above the air collection portions 31a and 31b. When the injection of pure water is continued as described above, all the air remaining in the pure water flowable range of the water electrolysis hydrogen oxygen generator 27 is expelled to the outside from the hollow rods 35a and 35b of the decompression cylinders 32a and 32b. It is.

  Thereafter, if the valves 36a and 36b and the valves 37a and 37b are closed, the pure water is cut off from the outside air, and only the inside of the decompression cylinders 32a and 32b comes into contact with the remaining air.

  In this state, when pure water is heated by the heaters 38a and 38b of the air collecting portions 31a and 31b, the air solubility of the pure water is lowered, and the air dissolved in the pure water becomes apparent as a gas. The exposed air rises to the upper part of the air collection parts 31a and 31b and is collected inside the above-described decompression cylinders 32a and 32b. As the trapped air increases, the hollow rods 35a, 35b are pushed up. When the push-up of the hollow rods 35a and 35b is completed, the hollow rods 35a and 35b of the decompression cylinders 32a and 32b are forcibly pulled up to increase the volume in the decompression cylinders 32a and 32b. The remaining air is depressurized. By this depressurization operation, the dissolved air in the pure water is further revealed and collected in the depressurization cylinders 32a and 32b. In this state, the valves 39a and 39b are closed so that the pure water is in a sealed state where the dissolved air is extremely small and does not contact any gas.

  When a DC voltage is applied to the positive and negative electrodes of the electrolytic cell 8 by the power supply device 9 in such a state where the sealed pure water circulates, oxygen and hydrogen are generated from the positive and negative electrodes of the electrolytic cell 8 respectively. . While oxygen and hydrogen are contained in pure water, the oxygen and hydrogen are transported to the gas-liquid separators 28a and 28b through the pipes 34a and 34b together with the flow of pure water. At this time, the generated pure water corresponding to the volume of hydrogen oxygen is such that the rods 40a and 40b of the buffer cylinders 30a and 30b rise vertically upward (upward in the drawing), and the internal volumes of the buffer cylinders 30a and 30b increase. Is absorbed by.

<Air collection parts 31a and 31b and decompression cylinders 32a and 32b>
In FIG. 2, the air collection parts 31a and 31b are composed of pure water inlets 41a and 41b, pure water tanks 42a and 42b, pipes 43a and 43b, pipes 44a and 44b, and heaters 38a and 38b. .

  The upper ends of the pure water inlets 41a and 41b are arranged vertically above the pipes 44a and 44b. The decompression cylinders 32a and 32b are composed of valves 39a and 39b, hollow rods 35a and 35b, and valves 36a and 36b.

  Immediately after the injection of pure water, pure water sent from the pump 6 is sent to the pure water tanks 42a and 42b from the pure water inlets 41a and 41b, and the air in the pure water tanks 42a and 42b is hollowed with the pipes 43a and 43b. Drive out to the outside through the rods 35a, 35b.

  At this time, the pure water itself circulates from the pipes 44 a and 44 b to the electrolysis cell 8. In the pure water in this state, an amount of air corresponding to the partial pressure of air in the atmosphere and the solubility determined by the temperature of the atmosphere is dissolved. Next, when the pure water in the pure water tanks 42a and 42b is heated by the heaters 38a and 38b, the solubility of the pure water in the air is reduced, so that the air becomes manifest as a gas. The air manifested in the pure water rises in the pure water tanks 42a and 42b by buoyancy and is expelled to the outside through the pipes 43a and 43b and the hollow rods 35a and 35b.

  As described above, after the dissolved water is removed by heating the pure water, the valves 36a and 36b are closed and the hollow rods 35a and 35b are pulled up by an external force (not shown) to increase the internal volumes of the decompression cylinders 32a and 32b. Reduce the internal air pressure. When the pressure drops, the air dissolved in the pure water becomes more obvious and is collected inside the decompression cylinders 32a and 32b. In this state, when the valves 39a and 39b are closed, the pure water is circulated in a sealed state in which dissolved air is removed by both heating and decompression and is not in contact with any gas.

  The upper ends of the pure water inlets 41a and 41b are arranged vertically above the pipes 44a and 44b. As a result, the pure water flows into the pipes 44a and 44b after passing through the pure water tanks 42a and 42b. The gas can be surely removed in the pure water tanks 42a and 42b.

<Buffer cylinders 30a and 30b>
In FIG. 2, buffer cylinders 30a and 30b are installed downstream of the gas-liquid separators 28a and 28b in the flow direction of pure water (arrows in FIG. 2). Pure water is a state in which dissolved air is removed and it circulates in a sealed state without contact with any gas. In this state, when a DC voltage is applied to the positive and negative electrodes of the electrolytic cell 8 by the power supply device 9, hydrogen and oxygen are generated from the pipes 34a and 34b, respectively.

  The hydrogen and oxygen are collected on the gas-liquid separators 28a and 28b and the upper portions of the storage tanks 29a and 29b, respectively. The generated pure water corresponding to the volume of hydrogen or oxygen flows into the buffer cylinders 30a and 30b from the gas-liquid separators 28a and 28b and the storage tanks 29a and 29b through the pipes 33a and 33b.

  At this time, the pure water that has flowed up pushes up the rods 40a and 40b. The number of moles of hydrogen and oxygen generated in the water electrolysis reaction of the electrolysis cell 8 is 2: 1. Therefore, the volume of the gas-liquid separators 28a and 28b, the storage tanks 29a and 29b, and the buffer cylinders 30a and 30b is 2: 1, and the volume of hydrogen and oxygen to be collected is 2: 1. The pressure was made equal. By doing so, the electrolyte membrane 7 that partitions the hydrogen-side flow path and the oxygen-side flow path inside the electrolytic cell 8 is prevented from causing a pressure difference, thereby preventing the electrolyte membrane 7 from being damaged due to the pressure difference. Can do.

<Process>
3 (a) to 5 (c) show a gas-liquid separator 28 (28a, 28b) and an air collecting unit used in the water electrolysis hydrogen oxygen generator 27 of the first embodiment of the present invention shown in FIG. It is a state transition diagram of 31 (31a, 31b). That is, from the start of the reaction preparation work, the action of the buffer cylinder 30 (30a, 30b) during the water electrolysis reaction, the full replacement of the storage tank 29 (29a, 29b) for storing hydrogen and oxygen generated by the water electrolysis reaction, It represents the state transition until the reaction start possible state again.

<Process 1: Start preparation work>
This will be described with reference to FIG. In FIG. 3A, the needle valve 45 is closed and all other valves are open (hereinafter, the hand valve is shown as being open and closed as ●), and the inlet 54 of the storage tank 29 is shown. Begin injecting pure water. Hereinafter, the rod 40 of the buffer cylinders 30a and 30b is fixed by the brake 46 until FIG.

  The next step will be described with reference to FIG. If the pure water injection is continued while the pump 6 is operated, the residual air in the pure water flowable range is expelled to the outside through the hollow rod 35 of the decompression cylinder 32 by the flowing pure water. As a result, the flowable range of pure water is completely filled with pure water, and the water surface is at a position beyond the height of the valve 37 of the storage tank 29 and to a middle height position inside the decompression cylinder 32. come. In this state, the valves 36 and 37 are closed.

  The next step will be described with reference to FIG. While operating the pump 6, the heater 38 is turned on in a state where the pure water circulates within the flowable range, and the pure water inside the air collecting unit 31 is heated. The air solubility of pure water decreases due to heating, and gaseous air that cannot be dissolved becomes apparent in the form of bubbles, rises by buoyancy, and is collected inside the decompression cylinder 32 through the pipe 43. At this time, since the valve 36 is closed, the hollow rod 35 of the decompression cylinder 32 rises by an amount corresponding to the volume of the collected air.

  The next step will be described with reference to FIG. When the lifting of the hollow rod 35 of the decompression cylinder 32 is finished, the hollow rod 35 of the decompression cylinder 32 is forcibly pulled up by another external force (not shown), and the internal volume of the decompression cylinder 32 is increased. Reduce internal pressure. In the first embodiment, the internal volume of the decompression cylinder 32 is increased to 5 times in FIG. 3 (d) compared to FIG. 3 (c). As a result, the pressure inside the decompression cylinder 32 is reduced to 1/5, and the partial pressure of the air in contact with pure water is reduced to 1/5. By this decompression operation, the air solubility of pure water further decreases, and the air as a gas that can no longer be dissolved becomes more apparent in the form of bubbles and rises by buoyancy, passes through the pipe 43 and enters the interior of the decompression cylinder 32. It is collected.

  The next step will be described with reference to FIGS. 3 (e) and 3 (f). When the manifestation of the dissolved air ends, the valve 39 is closed. As a result, the pure water is sealed within the flowable range without being in contact with any gas (FIG. 3 (e)). Next, the valve 36 is opened to return the pressure inside the decompression cylinder 32 to atmospheric pressure, and the hollow rod 35 that has been raised is lowered to the original position (FIG. 3 (f)). This operation is for ensuring safety and for preventing the hollow rod 35 from inadvertently moving. This completes the preparation of water electrolysis reaction start of the electrolysis cell 8.

<Process 2: From the start of water electrolysis reaction to full replacement of storage tank 29>
This will be described with reference to FIG. In the above state, a DC voltage is applied between the positive and negative electrodes of the electrolysis cell 8 to release the brake 46 of the rod 40 of the buffer cylinder 30. Hydrogen and oxygen generated in the water electrolysis reaction are transported from the electrolytic cell 8 through the pipe 34 to the inside of the gas-liquid separator 28 together with the pure water circulation flow. Hydrogen and oxygen rise in the pure water by buoyancy and are collected in the upper part of the storage tank 29 and the gas-liquid separator 28. Pure water is sealed within a flowable range and is incompressible. Accordingly, the generated pure water corresponding to the volume of hydrogen or oxygen moves to the buffer cylinder 30 through the pipe 33, pushes up the rod 40 of the buffer cylinder 30, and is stored in the space 47.

  The subsequent process will be described with reference to FIG. If the above reaction continues, the pressure of the hydrogen and oxygen collected in the storage tank 29 and the gas-liquid separator 28 is equal to the atmospheric pressure immediately after the rod 40 of the buffer cylinder 30 reaches the upper limit. As the reaction continues further, the pressure of hydrogen and oxygen rises above atmospheric pressure. In the first embodiment, the reaction was continued until the pressure gauge 48 reached 10 atm.

  The subsequent process will be described with reference to FIGS. 4C and 4D. When the above reaction is completed, the valves 49, 50, 51, 52 are closed, the metal fitting 53 is released, and the storage tank 29 in which hydrogen and oxygen have been collected is removed (FIG. 4 (c)). Next, an empty storage tank 29 is attached, and the valves 37, 51 and 52 are left open (FIG. 4 (d)).

<Process 3: Again until water electrolysis reaction is possible>
This will be described with reference to FIG. Next, as in FIG. 3 (b), pure water is injected from the inlet 54 at the top of the storage tank 29, and the valve 37 is closed when the water surface reaches a position exceeding the height of the valve 37 at the upper end of the storage tank 29. .

  The subsequent process will be described with reference to FIG. In the above state, when the valves 49 and 50 are opened, the pure water in the storage tank 29 and the high-pressure hydrogen and oxygen in the gas-liquid separator 28 are exchanged, and the water surfaces of both the pure water are at the same height.

  The subsequent process will be described with reference to FIG. When the needle valve 45 is opened little by little, the pure water in the storage tank 29 and the high-pressure hydrogen and oxygen in the gas-liquid separator 28 are pushed out to the outside. At the same time, the pressures of the pure water in the storage tank 29 and the hydrogen and oxygen in the gas-liquid separator 28 are reduced. When the water level reaches the lower limit by the water level pipe 55, the needle valve 45 is closed and the drainage is stopped. This state is a state in which the full replacement of the storage tank 29 is completed and the water electrolysis reaction can be started again. That is, although it is the same as that of the state of FIG.4 (b), the pressure of the pure water of the storage tank 29 and the hydrogen of the gas-liquid separation apparatus 28 and oxygen becomes a value of 1 atmosphere or more and 10 atmospheres or less.

<Process 4: Final work>
This will be described with reference to FIGS. 5 (a), 5 (b), and 5 (c). At the end of the operation of the water electrolysis hydrogen oxygen generator 27, first, application of a DC voltage to the electrolysis cell 8 is stopped. After removing the full storage tank 29 as shown in FIG. 5 (a), the connection port 56 of the gas-liquid separator 28 communicates with a dedicated exhaust pipe (not shown) maintained at atmospheric pressure or lower. Connect the exhaust hose (not shown) and open the valve 49. By this operation, high-pressure hydrogen and oxygen remaining in the upper part of the gas-liquid separator 28 pass through the exhaust hose and reach the exhaust dedicated pipe. After the remaining hydrogen and oxygen are sufficiently exhausted to reach atmospheric pressure in this way, the exhaust hose is removed. Next, the needle valve 45 and the valves 39 and 50 are opened, and the rod 40 of the buffer cylinder 30 is pushed down by an external force (not shown).

  By this operation (FIG. 5B), all the pure water in the pure water flowable range can be drained (FIG. 5C). When starting the production of hydrogen and oxygen again, in the state of FIG. 5C, the empty storage tank 29 is connected and the operation of FIG. 3A is started.

<Evaluation>
FIG. 6 is a schematic diagram of a fuel cell stack evaluation device 57. With this evaluation apparatus, the water electrolysis hydrogen oxygen generation apparatus 27 of the first embodiment is evaluated.

  The following four patterns of gas were supplied to generate power for the fuel cell. In other words, the following four patterns of gas were supplied to the same fuel cell stack to clarify the difference in performance.

  Gas (A): Comparative example, hydrogen containing 25% carbon dioxide as the negative electrode gas, and oxygen containing 80% nitrogen as the positive electrode gas are supplied. This is a gas having the same component as the gas supplied to a commercially available household fuel cell.

  Gas (B): Comparative Example, pure hydrogen is supplied as a negative electrode gas, and pure oxygen is supplied as a positive electrode gas. This is a gas in a commercially available hydrogen and oxygen cylinder, and the hydrogen concentration and oxygen concentration are 99.99% or more.

  Gas (C): Comparative example, hydrogen according to Patent Document 1 as negative electrode gas, and oxygen according to Patent Document 1 as positive electrode gas.

  Gas (D): Hydrogen produced by the water electrolysis hydrogen-oxygen generator of Embodiment 1 as the negative electrode gas, and oxygen produced in the same manner as the positive electrode gas are supplied. When generating the gas (D), the heaters 38a and 38b of the air collection parts 31a and 31b in FIG. 2 were set to 80 ° C. during the water electrolysis reaction.

  In addition, when producing | generating gas (C) and gas (D), the hydrogen and oxygen which generate | occur | produced in the initial stage of water electrolysis reaction were collected in the storage tank.

<Configuration of evaluation device>
FIG. 6 shows an evaluation device 57 for supplying the gas (D) from the gas (A) to evaluate the performance of the fuel cell, a supply device 58a for supplying the negative gas of the gas (A), and the gas (A). Supply device 58b for supplying positive gas, supply device 59a for supplying negative gas of gas (B), supply device 59b for supplying positive gas of gas (B), supply device 60a for supplying negative gas of gas (C) , A supply device 60b for supplying a positive gas of gas (C), a supply device 61a for supplying a negative gas of gas (D), and a supply device 61b for supplying a positive gas of gas (C).

  The evaluation device 57 includes a fuel cell stack 62, an inverter 63 that extracts current, a voltmeter 64 that measures voltage, a cooling water tank 65 that collects reaction heat, a cooling water pump 66, a heat exchanger 77, and a fuel cell. And mass flow controllers 67a and 67b for supplying positive and negative gas to the stack 62.

  The negative gas supply device 58a and the positive gas supply device 58b of the gas (A) are configured by storage tanks 68a and 68b in which the respective gases are sealed, and heated bubbling humidifiers 69a and 69b for humidifying the respective gases.

  The negative electrode gas supply device 59a and the positive gas supply device 59b of the gas (B) are constituted by storage tanks 70a and 70b in which the respective gases are sealed, and heated bubbling humidifiers 71a and 71b for humidifying the respective gases.

  The gas (C) negative electrode gas supply device 60a and the positive gas supply device 60b are constituted by storage tanks 72a and 72b in which the respective gases are sealed, and heated bubbling humidifiers 73a and 73b for humidifying the respective gases.

  The negative gas supply device 61a and the positive gas supply device 61b of the gas (D) are configured by storage tanks 74a and 74b and heaters 75a and 75b in which the respective gases are sealed.

<Evaluation device process>
When introducing gas (A) to gas (D) into the evaluation device 57, connection ports Aa, Ba, Ca, Da and connection port Fa are connected, connection ports Ab, Bb, Cb, Db and connection port Fb are connected. The fuel cell stack 62 was connected to supply a negative electrode gas and a positive electrode gas.

  Among these, when supplying the gas (A), gas (B), and gas (C) to the evaluation device 57, the heating bubbling humidifiers 69a, 69b, 71a, 71b, 73a, 73b are heated to 65 ° C. Humidified.

  Moreover, when supplying gas (D) to the evaluation apparatus 57, heater 75a, 75b was heated to 65 degreeC. The mass flow controllers 67a and 67b were heated to 90 ° C. by the heaters 76a and 76b. The reason why the mass flow controllers 67a and 67b are heated is to heat the mass flow controllers 67a and 67b to a temperature higher than the dew point of the gas to be supplied, thereby preventing a failure due to condensation inside the mass flow controllers 67a and 67b.

  When the gases (A) to (D) are supplied in the above-described state, the fuel cell stack 62 enters an open circuit state (referred to as OCV), and then an electric current is taken out by the inverter 63.

  At this time, the stepped current is increased until the required current value is reached. At this time, as the characteristics of the fuel cell stack 62, the voltage drops as the current to be extracted increases (referred to as IV characteristics), but when the voltage value stabilizes with time after reaching the final current value, the voltage value is This is an index for evaluating the performance of the stack 62. Further, in order to stabilize the voltage of the fuel cell stack 62 during power generation, it is necessary to stabilize the temperature of the cooling water flowing through the cooling water path in the fuel cell stack 62. Therefore, the set temperature of the heat exchanger 77 and the flow rate set value of the cooling water pump 66 in FIG. 6 are adjusted so that the cooling water to the fuel cell stack 62 has an inlet temperature of 60 ° C. and an outlet temperature of 70 ° C.

  With the evaluation device 57 as described above, the voltage ratio of the fuel cell stack 62 when the gas (A) to the gas (D) are supplied is as shown in Table 1, where the voltage ratio of the gas (B) is 100. The voltage ratio of gas (A) was 90.7, the voltage ratio of gas (C) was 99.2, and the voltage ratio of gas (D) was 99.7.

  The voltage ratio of Comparative Example 1 is 90.7%, while the stable voltage ratio of Comparative Example 2 is 100%. In Comparative Example 1, hydrogen containing 25% carbon dioxide is supplied to the negative electrode and oxygen containing 80% nitrogen is supplied to the positive electrode, whereas in Comparative Example 2, pure hydrogen is supplied to the negative electrode and pure oxygen is supplied to the positive electrode. It is to be done. This is because an output improvement effect called a gain voltage appears.

  In addition, the voltage ratio of the example is 99.7%, which is almost the same as the voltage ratio of the comparative example 2. Therefore, according to the water electrolysis hydrogen oxygen generator of Embodiment 1 of the present invention, it can be seen that almost 100% of hydrogen and oxygen can be collected from the initial reaction of the electrolysis cell.

  On the other hand, the voltage ratio of Comparative Example 3 is 99.2%, which is slightly smaller than the voltage ratio of Example 99.7%. However, a deoxygenation column 24 is used. In the embodiment, the above values are obtained without using the deoxygenation column 24.

  There are three possible causes for the decrease in the voltage ratio in Comparative Example 3.

  The first is that at the beginning of the water electrolysis reaction, the oxygen concentration in the storage tank was lower than that of pure oxygen due to the air remaining in the oxygen side piping, pure water tank and storage tank. .

  Second, the temperature of pure water rises due to the water electrolysis reaction heat of the electrolysis cell 8, and the dissolved air in the pure water becomes obvious and is collected in the storage tank together with oxygen, so the oxygen concentration in the storage tank is It is lower than pure oxygen.

  The third is that the dissolved air in the pure water passes through the electrolyte membrane and reaches the hydrogen side, and flows downstream with the generated hydrogen, and is stored in a storage tank by a gas other than oxygen, such as carbon dioxide and argon, that cannot be removed by the deoxygenation column. It is that the hydrogen concentration in the inside decreased.

  In the embodiment, the above three points are solved, and the voltage ratio is considered high.

  The water electrolysis hydrogen-oxygen generator of the present invention heats pure water to the optimum temperature for the water electrolysis reaction in advance of the water electrolysis reaction, and depressurizes the air phase in contact with the deionized water. The air dissolved in the air can be revealed in the air collecting part.

  Further, by shutting off the air collecting part from pure water, the pure water can be in a sealed state where it does not come into contact with any gas. Thereafter, since the water electrolysis reaction is started, it does not come into contact with a gas other than hydrogen or oxygen to be collected even during the water electrolysis reaction.

  Therefore, from the start of the water electrolysis reaction to the end of the reaction, it is always possible to store high concentrations of hydrogen and oxygen that do not contain any gas other than water vapor and hydrogen, and water vapor and oxygen. Therefore, the hydrogen / oxygen generator is optimal for supplying hydrogen or oxygen to facilities using hydrogen or oxygen.

(Note)
In the above example, both oxygen and hydrogen were generated. However, only one of them may be generated. That is, one gas is not recovered, and the other gas is recovered and provided in the above example.

  For example, in the case of a hydrogen generator, the water electrolysis hydrogen oxygen generator 27 in FIG. 2 is only required on the left side. It comprises an electrolysis cell 8, a hydrogen gas-liquid separator 28a, a hydrogen storage tank 29a, a hydrogen buffer cylinder 30a, a hydrogen air collecting part 31a, and a hydrogen decompression cylinder 32a. The In the case of an oxygen generator, the components on the opposite side to the above in FIG.

The water electrolysis hydrogen oxygen generator of the present invention can be used as a device for supplying hydrogen or oxygen.

DESCRIPTION OF SYMBOLS 1 Gas production | generation apparatus 2 Pure water source 3 Reservoir 4 Pump 5 Oxygen side gas-liquid separation apparatus 6 Pump 7 Electrolyte membrane 8 Electrolysis cell 9 Power supply apparatus 11 Upper gas phase part 12 Lower liquid phase parts 10, 13, 15, 19, 20, 22, 23, 33, 33a, 34, 34a, 43, 43a, 44a Pipe 14 Oxygen side storage tank 16 Lower liquid phase part 17 Ejection port 18 Upper gas phase part 21 Hydrogen side gas-liquid separator 24 Deoxygenation column 25 Dehydration Column 26 Hydrogen-side storage tank 27 Water electrolysis hydrogen oxygen generator 28 Gas-liquid separator 28a Gas-liquid separator 29, 29a Storage tank 30, 30a Buffer cylinder 31, 31a Air collector 32, 32a Decompression cylinder 35, 35a Hollow rod 36, 36a, 37, 37a, 39, 39a Valve 38, 38a Heater 40, 40a Rod 41a Pure water inlet 42a Pure water tank 45 Needle valve 46 Brake 47 Space 48 Pressure gauge 49 Valve 53 Metal fitting 54 Inlet 55 Water level pipe 56 Connection port 57 Evaluation device 58a, 58b, 59a, 59b, 60a, 60b, 61a, 61b Supply device 62 Fuel cell stack 63 Inverter 64 Voltage Total 65 Cooling water tank 66 Cooling water pump 67a Mass flow controllers 68a, 70a Storage tank 69a Heated bubbling humidifier 71a, 73a Heated bubbling humidifier 72a, 74a Storage tank 75a, 76a Heater 77 Heat exchanger 99 Voltage ratio Aa, Ab , Fa, Fb connection port

Claims (12)

An electrolysis cell that electrolyzes water to produce hydrogen and oxygen;
An air collection device connected to the electrolysis cell;
A gas-liquid separator that separates and collects hydrogen or oxygen generated from the electrolytic cell from the water;
A buffer cylinder coupled to the electrolysis cell;
A storage tank connected to the gas-liquid separator and storing the hydrogen or oxygen;
A gas generating device. The gas generation device according to claim 1, wherein the buffer cylinder has a variable internal volume. The gas generating device according to claim 1, wherein an inlet end of water to the air collecting device is located at an upper part in a vertical direction from an outlet of water to the outside from the air collecting device. A heater for heating the water is provided at a lower portion of the air collecting device, and air generated from the water heated by the heater is collected at an upper portion of the air collecting device by buoyancy. 4. The gas generator according to any one of items 1 to 3. The gas production | generation apparatus of any one of Claim 1 to 4 with which the air collection cylinder was connected with the perpendicular direction upper part of the said air collection apparatus. The gas generator according to claim 5, wherein the collected air can be depressurized by enlarging the internal volume of the air collecting cylinder. The gas generating device according to claim 5 or 6, wherein the air collecting cylinder has a mechanism capable of expelling internal air to the outside. The gas generator according to any one of claims 5 to 7, wherein the water can be sealed so as not to come into contact with any gas by operation of a connection valve of the air collecting cylinder. The gas generator according to any one of claims 1 to 8, wherein the water can be circulated in a sealed state. The gas generating device according to any one of claims 1 to 9, wherein water corresponding to a volume corresponding to hydrogen and oxygen generated from the electrolysis cell can be stored by expanding an internal volume of the buffer cylinder. The electrolysis cell is one,
The air collection device for hydrogen connected to the electrolysis cell;
The gas-liquid separator for hydrogen that separates and collects hydrogen generated from the electrolysis cell from the water; and
The buffer cylinder for hydrogen connected to the electrolysis cell;

The storage tank for hydrogen storing the hydrogen;
The air collection device for oxygen connected to the electrolysis cell;
The gas-liquid separator for oxygen that separates and collects oxygen generated from the electrolytic cell from the water; and
The buffer cylinder for oxygen connected to the electrolysis cell;
The storage tank for oxygen storing the hydrogen or the oxygen;
The gas production | generation apparatus of any one of Claims 1-10 containing these. An introduction step of introducing water into each of the devices connected to the electrolysis cell, the air collection unit, the gas-liquid separation unit, and the storage tank;
An air collecting step of heating the water and collecting a gas in the water with the air collecting device;
A gas generation step of decomposing the water and generating hydrogen or oxygen in the electrolysis cell;
A separation step of separating the generated hydrogen or oxygen from the water with a gas-liquid separator;
A storage step of collecting or storing the hydrogen or oxygen in the storage tank;
A gas generation method comprising:

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