Dry water electrolysis hydrogen gas producing apparatus

Abstract

To provide a dry water electrolysis hydrogen gas producing apparatus capable of smoothly producing dry water electrolysis hydrogen gas even during a restart-up time.SOLUTION: Provided is a dry water electrolysis hydrogen gas producing apparatus including a water electrolysis device that electrolyzes water to generate humid water electrolysis hydrogen gas containing hydrogen and water vapor, an absorber that brings the humid water electrolysis hydrogen gas into contact with an absorbent liquid to obtain dry water electrolysis hydrogen gas and humid absorbent liquid, a hydrogen booster pump that pressurizes the dry water electrolysis hydrogen gas, a storage device that stores the pressurized dry water electrolysis hydrogen gas, a regenerator that brings the humid absorbent liquid into contact with regeneration dry hydrogen gas (dry water electrolysis hydrogen gas) to obtain dry absorbent liquid and humid regeneration hydrogen gas, and a liquid delivery pump that sends the humid absorbent liquid to the regenerator, where the humid regeneration hydrogen gas has a higher pressure than the humid water electrolysis hydrogen gas, and this pressure difference is used as a driving force to introduce the dry water electrolysis hydrogen gas from the regenerator to the water electrolysis device.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present application relates to a dry water electrolysis hydrogen gas production apparatus. [Background technology]

[0002] Patent Documents 1 to 3 disclose dry water electrolysis hydrogen gas production equipment. The dry water electrolysis hydrogen gas production equipment is mainly composed of a water electrolysis device, an absorber, and a regenerator. The water electrolysis device electrolyzes water to generate wet water electrolysis hydrogen gas containing hydrogen and water vapor. The absorber brings the wet water electrolysis hydrogen gas into contact with an absorbing solution to obtain dry water electrolysis hydrogen gas and a wet absorbing solution. The regenerator removes moisture from the wet absorbing solution to regenerate the absorbing solution. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7116397 [Patent Document 2] JP 2018-51543 A [Patent Document 3] Patent Publication No. 2021-7938 Summary of the Invention [Problem to be solved by the invention]

[0004] In the regenerator, a part of the produced dry water electrolysis hydrogen gas may be used as dry hydrogen gas for regeneration and brought into contact with the wet absorbing solution to remove moisture from the wet absorbing solution and regenerate the absorbing solution.

[0005] However, when restarting the device, it is necessary to first introduce regeneration gas into the regenerator. In the configuration of the conventional technology, when part of the dry water electrolysis hydrogen gas is used as the dry hydrogen gas for regeneration, there is a problem that the dry water electrolysis hydrogen gas cannot be produced because there is no dry water electrolysis hydrogen gas at the start of the device.

[0006] In view of the above circumstances, a main object of the present disclosure is to provide a dry water electrolysis hydrogen gas production apparatus that can smoothly produce dry water electrolysis hydrogen gas even when restarted. [Means for solving the problem]

[0007] A first aspect of the present disclosure is a dry water electrolysis hydrogen gas production apparatus including: a water electrolysis device that electrolyzes water to produce wet water electrolysis hydrogen gas containing hydrogen and water vapor; an absorber that brings the wet water electrolysis hydrogen gas into contact with an absorbing liquid to obtain dry water electrolysis hydrogen gas with reduced humidity and a wet absorbing liquid that selectively absorbs water vapor; a hydrogen boost pump that boosts the dry water electrolysis hydrogen gas; a storage device that stores the pressurized dry water electrolysis hydrogen gas; a regenerator that brings the wet absorbing liquid into contact with dry hydrogen gas for regeneration to obtain a dry absorbing liquid with reduced moisture content and wet regenerating hydrogen gas with increased humidity; and a liquid delivery pump that delivers the wet absorbing liquid to the regenerator; the dry hydrogen gas for regeneration is the dry water electrolysis hydrogen gas stored in the storage device, and the wet regenerating hydrogen gas has a higher pressure than the wet water electrolysis hydrogen gas, and is introduced from the regenerator to the water electrolysis device using the pressure difference between them as a driving force. Effect of the Invention

[0008] In the dry water electrolysis hydrogen gas production apparatus of the present disclosure, the dry water electrolysis hydrogen gas stored after pressure increase is used as the dry hydrogen gas for regeneration, so that the dry hydrogen gas for regeneration can be introduced into the regenerator even during restart. Therefore, the dry water electrolysis hydrogen gas production apparatus of the present disclosure can smoothly produce dry water electrolysis hydrogen gas even during restart. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram of a dry water electrolysis hydrogen gas production apparatus 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Dry water electrolysis hydrogen gas production equipment] The dry water electrolysis hydrogen gas production apparatus of the present disclosure is an apparatus for continuously producing dry water electrolysis hydrogen gas. The dry water electrolysis hydrogen gas production apparatus of the present disclosure will be described using a dry water electrolysis hydrogen gas production apparatus 1 as one embodiment.

[0011] A block diagram of the dry water electrolysis hydrogen gas production apparatus 1 is shown in Fig. 1. As shown in Fig. 1, the dry water electrolysis hydrogen gas production apparatus 1 mainly includes a water electrolysis device 10 that electrolyzes water to generate wet water electrolysis hydrogen gas 20 containing hydrogen and water vapor, an absorber 30 that brings the wet water electrolysis hydrogen gas 20 into contact with an absorbing liquid (dry absorbing liquid 38) to obtain a dry water electrolysis hydrogen gas 261 with reduced humidity and a wet absorbing liquid 37 that selectively absorbs water vapor, a hydrogen boost pump 28 that boosts the dry water electrolysis hydrogen gas 261, a storage device 27 that stores the boosted dry water electrolysis hydrogen gas 261, a regenerator 34 that brings the wet absorbing liquid 37 into contact with a dry hydrogen gas 40 for regeneration to obtain a dry absorbing liquid 38 with reduced moisture content and a wet hydrogen gas for regeneration 45 with increased humidity, and a liquid delivery pump 35 that delivers the wet absorbing liquid 37 to the regenerator 34. Other members will be described later as necessary.

[0012] <Water electrolysis device 10> The water electrolysis device 10 electrolyzes water to generate wet-water electrolysis hydrogen gas 20 containing hydrogen and water vapor. The water electrolysis device 10 generates oxygen in addition to the wet-water electrolysis hydrogen gas 20. The form of the water electrolysis device 10 is not particularly limited, and examples thereof include an alkaline water electrolysis device, a solid polymer water electrolysis device, and a high-temperature steam electrolysis device.

[0013] Wet-water electrolyzed hydrogen gas 20 produced in the water electrolysis device 10 undergoes heat exchange with cooling water 22 in the heat exchanger 21 and is adjusted to a desired temperature. Then, the flow rate of the wet-water electrolyzed hydrogen gas 20 is controlled by a flow rate controller 231 and sent to the absorber 30.

[0014] <Absorber 30> The absorber 30 brings the wet water electrolysis hydrogen gas 20 into contact with an absorbing liquid (dry absorbing liquid 38) to obtain a dry water electrolysis hydrogen gas 261 with reduced humidity and a wet absorbing liquid 37 that selectively absorbs water vapor. The absorber 30 functions as a gas-liquid separator, and the dry water electrolysis hydrogen gas 261 and the wet absorbing liquid 37 are separated into gas and liquid.

[0015] The absorbing liquid is a liquid absorbing medium having the property of absorbing and releasing water. For example, a mixed solution of an ionic liquid and an inorganic salt can be used. The absorbing liquid and the inorganic salt can be, for example, the absorbing liquid and the inorganic salt described in any one of Patent Documents 1 to 3.

[0016] As shown in Fig. 1, the absorbing liquid (dry absorbing liquid 38) is introduced from the top of the absorber 30, and the wet water electrolysis hydrogen gas 20 is introduced from the bottom of the absorber 30. They come into contact with each other inside the absorber 30. The absorbing liquid in the absorber 30 may be temperature controlled. For example, the temperature may be kept constant at 25°C. The pressure inside the absorber 30 may be controlled by providing a pressure regulating valve or the like.

[0017] Water vapor in the wet water electrolysis hydrogen gas 20 is absorbed by the absorbing liquid and reduced. The hydrogen gas with reduced moisture (dry water electrolysis hydrogen gas 261) is introduced into the trap 24 from the top of the absorber 30. The trap 24 can remove the absorbing liquid entrained by the hydrogen. The hydrogen that has passed through the trap 24 is passed through a dew point meter 25 to measure the dew point, and is sent to a hydrogen boost pump 28. The absorbing liquid that has absorbed moisture in the absorber 30 (wet absorbing liquid 37) is sent from the bottom of the absorber 30 to a liquid sending pump 35, passes through a flow meter 31, a heat exchanger 321, and a heater 33, and is introduced into the regenerator 34.

[0018] <Hydrogen booster pump 28> The hydrogen boost pump 28 boosts the pressure of the dry water electrolysis hydrogen gas 261. As a result, the pressure of the dry water electrolysis hydrogen gas 261 becomes higher than that of the wet water electrolysis hydrogen gas 20, and as described below, the water electrolysis hydrogen gas can be circulated using the pressure difference as a driving force. A known pump can be used as the hydrogen boost pump 28.

[0019] <Storage Unit 27> The storage device 27 stores the dry water electrolysis hydrogen gas 261 boosted by the hydrogen boost pump. A portion of the dry water electrolysis hydrogen gas 261 stored in the storage device 27 is appropriately extracted and used as the dry hydrogen gas 40 for regeneration.

[0020] As shown in FIG. 1, the dry hydrogen gas for regeneration 40 (dry water electrolysis hydrogen gas 261) discharged from the storage device 27 is reduced to a predetermined pressure by a regulator 411 and introduced into the regenerator 34 through a flow meter 42.

[0021] <Regenerator 34> The regenerator 34 brings the wet absorbing liquid 37 into contact with the dry hydrogen gas for regeneration 40 to obtain a dry absorbing liquid 38 having a reduced moisture content and a wet hydrogen gas for regeneration 48 having an increased humidity.

[0022] As described above, the wet absorbing liquid 37 is heated by the heater 33 and adjusted to a predetermined temperature. For example, it may be adjusted to a constant temperature such as 100°C, 80°C, or 60°C. The flow rate of the dry hydrogen gas for regeneration 40 is not particularly limited, but for example, the wet absorbing liquid 37:dry hydrogen gas for regeneration 40 (volume ratio (atmospheric pressure)) is preferably 1:300 to 1:1, and more preferably 1:200 to 1:1. A smaller amount of the dry hydrogen gas for regeneration 40 is preferable because it reduces the energy required for regeneration.

[0023] 1, the wet absorbing liquid 37 is introduced from the top of the regenerator 34. The dry hydrogen gas for regeneration 40 is introduced from the bottom of the regenerator 34. They come into contact with each other inside the regenerator 34. The moisture in the wet absorbing liquid 37 is absorbed by the dry hydrogen gas for regeneration 40 and decreases. The wet absorbing liquid 37 is dried to approximately the vapor pressure of the dry hydrogen gas for regeneration 40 introduced into the regenerator 34.

[0024] The obtained dry absorption liquid 38 (regenerated absorption liquid) is discharged from the bottom of the regenerator 34. The discharged dry absorption liquid 38 undergoes heat exchange in the heat exchangers 321 and 322. Here, since the pressure inside the regenerator 34 is higher than the pressure inside the absorber 30, the dry absorption liquid 38 is spontaneously introduced from the regenerator 34 to the absorber 30.

[0025] The obtained wet regeneration hydrogen gas 48 is reduced in pressure to a predetermined level via regulator 412 and introduced into the water electrolysis device 10. Here, the wet regeneration hydrogen gas 48 is reduced in pressure by regulator 412, but the pressure is set higher than the pressure of the wet water electrolysis hydrogen gas 20. Therefore, with the pressure difference as a driving force, the wet regeneration hydrogen gas 48 is spontaneously introduced from the regenerator 34 into the water electrolysis device 10.

[0026] <Liquid transfer pump 35> The liquid sending pump 35 sends the wet absorbing liquid 37 to the regenerator 34. The sent wet absorbing liquid 37 passes through the flowmeter 31, the heat exchanger 321, and the heater 33, and is introduced into the regenerator 34. In the heat exchanger 321, heat is exchanged between the wet absorbing liquid 37 and the dry absorbing liquid 38. As described above, the pressure inside the regenerator 34 is higher than the pressure inside the absorber 30. Therefore, the movement of the dry absorbing liquid 38 (absorbing liquid) from the regenerator 34 to the absorber 30 occurs spontaneously, but the reverse does not occur. For this reason, the liquid sending pump 35 is provided, which circulates the absorbing liquid.

[0027] <Effects> In the dry water electrolysis hydrogen gas production apparatus 1, the dry water electrolysis hydrogen gas 261 stored after pressure increase is used as the dry hydrogen gas for regeneration 40, so that the dry hydrogen gas for regeneration can be introduced into the regenerator even during restart. Therefore, the dry water electrolysis hydrogen gas production apparatus of the present disclosure can smoothly produce dry water electrolysis hydrogen gas even during restart. Details will be described below.

[0028] (When the device is stopped) During normal operation, the three-way valve 44 is set to the water electrolysis device 10 side, and the wet regeneration hydrogen gas 48 flows from the regenerator to the water electrolysis device 10. When the device is stopped, the three-way valve 44 is switched from the water electrolysis device 10 side to the exhaust port 43 side, and the valves on the inlet and outlet sides of the absorber 30 are closed. As a result, the wet regeneration hydrogen gas 48 is exhausted from the exhaust port 43. When the device is stopped, the water electrolysis device 10 is stopped and the supply of the wet water electrolysis hydrogen gas 20 is stopped. On the other hand, even when the device is stopped, the liquid delivery pump 35 continues to operate and the dry regeneration hydrogen gas 40 continues to be supplied from the lower part of the regenerator 34. As a result, the entire absorption liquid circulating in the absorber 30 and the regenerator 34 can be dried by gas-liquid contact. After the entire absorption liquid is sufficiently dried, the valves on the inlet and outlet sides of the regenerator 34 are closed to stop the supply of the dry regeneration hydrogen gas 40, and the operation of the liquid delivery pump 35 is stopped.

[0029] (When restarting) The liquid delivery pump 35 is operated to start circulation of the absorption liquid between the regenerator 34 and the absorber 30. Next, the three-way valve 44 is switched from the exhaust port 43 side to the water electrolysis device 10 side, and the inlet and outlet valves of the absorber 30 and the regenerator 34 are opened to start circulation of the wet water electrolysis hydrogen gas 20 and the dry hydrogen gas for regeneration 40.

[0030] (effect) In the configuration of the conventional technology, when a part of the dry water electrolysis hydrogen gas is used as the dry hydrogen gas for regeneration, there is a problem that the dry water electrolysis hydrogen gas cannot be produced when the device is started because there is no dry water electrolysis hydrogen gas itself. In addition, even if the configuration of the conventional technology is used, the above problem does not occur if the hydrogen boost pump and the liquid delivery pump are always operated, including when there is no need to operate the regenerator, such as when water electrolysis is stopped, but this leads to a problem of wasting energy to operate the actuators all the time. In contrast, the dry water electrolysis hydrogen gas production device 1 can use the stored dry hydrogen gas for regeneration 40, so that dry water electrolysis hydrogen gas can be produced smoothly even when restarted. In addition, when the device is stopped, all the actuators of the entire device can be stopped, which contributes to energy saving.

[0031] In addition, in the configuration of the conventional technology, a hydrogen boost pump is required when circulating hydrogen gas with increased humidity due to the movement of moisture from the wet absorbent during absorption solution regeneration to the water electrolysis device. Hydrogen boost pumps are generally expensive, which increases the initial cost of the entire device. In contrast, in the dry water electrolysis hydrogen gas production device 1, the pressure difference between the wet regeneration hydrogen gas 45 and the wet water electrolysis hydrogen gas 20 is used as a driving force to spontaneously move the wet regeneration hydrogen gas 48 from the regenerator 34 to the water electrolysis device 10, so there is no need to install a hydrogen boost pump for moving the wet regeneration hydrogen gas 48 from the regenerator 34 to the water electrolysis device 10.

[0032] The dry water electrolysis hydrogen gas production apparatus of the present disclosure has been described above using one embodiment. The dry water electrolysis hydrogen gas production apparatus of the present disclosure can smoothly produce dry water electrolysis hydrogen gas even when restarted.

[0033] [Dry water electrolysis hydrogen gas production method] The method for producing dry water electrolysis hydrogen gas according to the present disclosure is as follows: That is, the method for producing dry water electrolysis hydrogen gas includes a water electrolysis step of producing wet water electrolysis hydrogen gas containing hydrogen and water vapor by electrolyzing water, an absorption step of bringing the wet water electrolysis hydrogen gas into contact with an absorbing liquid to obtain dry water electrolysis hydrogen gas with reduced humidity and a wet absorbing liquid that selectively absorbs water vapor, a pressure increase step of increasing the pressure of the dry water electrolysis hydrogen gas, a storage step of storing the pressurized dry water electrolysis hydrogen gas, a regeneration step of bringing the wet absorbing liquid into contact with a dry hydrogen gas for regeneration to obtain a dry absorbing liquid with reduced moisture content and a wet regenerating hydrogen gas with increased humidity, and a liquid delivery step of delivering the wet absorbing liquid to the regeneration step, in which the dry hydrogen gas for regeneration is the dry water electrolysis hydrogen gas stored in a storage device, and the wet regenerating hydrogen gas has a higher pressure than the wet water electrolysis hydrogen gas, and is introduced from the regeneration step to the water electrolysis step using the pressure difference between the two as a driving force.

[0034] The method for producing dry water electrolysis hydrogen gas according to the present disclosure can be carried out using the above-mentioned dry water electrolysis hydrogen gas production device. According to the method for producing dry water electrolysis hydrogen gas according to the present disclosure, dry water electrolysis hydrogen gas can be produced smoothly even at the time of restart. The details of the method for producing dry water electrolysis hydrogen gas according to the present disclosure have been described above, so a detailed description thereof will be omitted here. [Explanation of symbols]

[0035] 1. Water electrolysis hydrogen gas production equipment 10 Water electrolysis equipment 20 Wet water electrolysis hydrogen gas 21 Heat exchanger 22 Cooling water 231 Flow control meter 24 Trap 25 Dew point meter 261 Dry Water Electrolysis Hydrogen Gas 27 Storage Device 28 Hydrogen booster pump 30 Absorber 31 Flow meter 321 Heat exchanger 322 Heat Exchanger 33 Heater 34 Regenerator 35 Liquid delivery pump 36 Cooling water 37 Wet absorbent 38 Dry Absorbent 40 Dry hydrogen gas for regeneration 411 Regulator 412 Regulator 42 Flow meter 43 Exhaust port 44 Three-way switching valve 45 Hydrogen gas for wet regeneration

Claims

[Claim 1] a water electrolysis device that electrolyzes water to generate wet water electrolysis hydrogen gas containing hydrogen and water vapor; an absorber that brings the wet water electrolysis hydrogen gas into contact with an absorbing solution to obtain a dry water electrolysis hydrogen gas having reduced humidity and a wet absorbing solution that selectively absorbs the water vapor; a hydrogen booster pump that boosts the dry water electrolysis hydrogen gas; a storage device for storing the pressurized dry water electrolysis hydrogen gas; a regenerator for contacting the wet absorbing liquid with dry hydrogen gas for regeneration to obtain a dry absorbing liquid having a reduced moisture content and a wet hydrogen gas for regeneration having an increased humidity; A liquid sending pump that sends the wet absorbing liquid to the regenerator, the dry hydrogen gas for regeneration is the dry water electrolysis hydrogen gas stored in the storage device, The wet regenerating hydrogen gas has a higher pressure than the wet water electrolysis hydrogen gas, and is introduced from the regenerator to the water electrolysis device using the pressure difference as a driving force. Dry water electrolysis hydrogen gas production equipment.

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