Dry water electrolysis hydrogen gas producing device

Abstract

To provide a dry water electrolysis hydrogen gas producing device capable of cutting cost.SOLUTION: Provided is a dry water electrolysis hydrogen gas producing device that includes a water electrolysis device that electrolyzes water to generate wet water electrolysis hydrogen gas, a heat exchanger that lowers a dew point of the wet water electrolysis hydrogen gas discharged from the water electrolysis device to obtain low-humidity water electrolysis hydrogen gas, an absorber that brings the low-humidity water electrolysis hydrogen gas into contact with an absorbent liquid to obtain dry water electrolysis hydrogen gas and wet absorbent liquid, a regenerator that brings the wet absorbent liquid into contact with dry hydrogen gas for regeneration (low-humidity water electrolysis hydrogen gas) to obtain dry absorbent liquid and wet regeneration hydrogen gas, a liquid delivery pump that sends the wet absorbent liquid to the regenerator, a diverter valve placed between the heat exchanger and the absorber, and a regulator placed between the diverter valve and the absorber that reduces the pressure of the wet water electrolysis hydrogen gas, with the pressure of the regenerator being higher than the pressure at the inlet of the absorber, driving the wet regeneration hydrogen gas from the regenerator to the absorber due to this pressure difference.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, the dry hydrogen gas for regeneration may be brought into contact with the wet absorbing liquid to regenerate the absorbing liquid. In this case, it is desirable to circulate the dry hydrogen gas for regeneration (wet hydrogen gas for regeneration) with increased humidity to the water electrolysis device in order to prevent a decrease in production efficiency. However, when circulating the wet hydrogen gas for regeneration from the outlet of the regenerator to the water electrolysis device, a hydrogen boost pump is required because the hydrogen pressure in the water electrolysis device is higher than the regenerator pressure, which creates a problem of increasing the initial cost of the entire device.

[0005] In view of the above-mentioned circumstances, a main object of the present disclosure is to provide a dry water electrolysis hydrogen gas production apparatus that enables cost reduction. [Means for solving the problem]

[0006] A first aspect of the present disclosure includes a water electrolysis device that electrolyzes water to generate wet water electrolysis hydrogen gas containing hydrogen and water vapor, a heat exchanger that lowers the dew point of the wet water electrolysis hydrogen gas discharged from the water electrolysis device to obtain low-humidity water electrolysis hydrogen gas, an absorber that brings the low-humidity 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 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 hydrogen gas for regeneration with increased humidity, and a regenerator that delivers the wet absorbing liquid to the regenerator. a diversion valve disposed between the heat exchanger and the absorber for circulating a portion of the low-humidity water electrolysis hydrogen gas to the absorber side and the remainder to the regenerator side; and a regulator disposed between the diversion valve and the absorber for reducing the pressure of the low-humidity water electrolysis hydrogen gas discharged from the diversion valve toward the absorber, wherein the dry hydrogen gas for regeneration is low-humidity water electrolysis hydrogen gas, the pressure of the regenerator is higher than the pressure at the absorber inlet, and the wet hydrogen gas for regeneration moves from the regenerator to the absorber using the pressure difference as a driving force. Effect of the Invention

[0007] In the dry water electrolysis hydrogen gas production apparatus of the present disclosure, the pressure in the regenerator is higher than the pressure at the absorber inlet, and the wet regeneration hydrogen gas moves from the regenerator to the absorber using the pressure difference as a driving force. Therefore, a hydrogen boost pump is not required for the movement of the wet regeneration hydrogen gas. Therefore, the dry water electrolysis hydrogen gas production apparatus of the present disclosure can reduce costs. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram of a dry water electrolysis hydrogen gas production apparatus 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [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.

[0010] A block diagram of a dry water electrolysis hydrogen gas production apparatus 1 is shown in Figure 1. As shown in Figure 1, the dry water electrolysis hydrogen gas production apparatus 1 mainly includes a water electrolysis device 10 that electrolyzes water to produce wet water electrolysis hydrogen gas 20 containing hydrogen and water vapor, a heat exchanger 21 that lowers the dew point of the wet water electrolysis hydrogen gas 20 discharged from the water electrolysis device 10 to obtain low-humidity water electrolysis hydrogen gas, an absorber 30 that brings the low-humidity water electrolysis hydrogen gas into contact with an absorbing liquid (dry absorbing liquid 38) to obtain dry water electrolysis hydrogen gas 26 with reduced humidity and wet absorbing liquid 37 that selectively absorbs water vapor, and a dry hydrogen gas 40 for regeneration that is supplied to the wet absorbing liquid 37. The system further comprises a regenerator 34 that contacts the absorbent 30 with a dry absorption solution 38 having a reduced moisture content and a wet hydrogen gas for regeneration 45 having an increased humidity, a liquid feed pump 35 that feeds the wet absorption solution 37 to the regenerator 34, a diverter valve 28 that is disposed between the heat exchanger 21 and the absorber 30 and distributes a portion of the low-humidity water electrolysis hydrogen gas to the absorber 30 side and the remainder to the regenerator 34 side, and a regulator 29 that is disposed between the diverter valve 28 and the absorber 30 and reduces the pressure of the low-humidity water electrolysis hydrogen gas discharged from the diverter valve 28 toward the absorber 30. Other members will be described later as necessary.

[0011] <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. The wet-water electrolysis hydrogen gas 20 generated in the water electrolysis device 10 is sent to a heat exchanger 21.

[0012] <Heat exchanger 21> The heat exchanger 21 lowers the dew point of the wet water electrolysis hydrogen gas 20 discharged from the water electrolysis device 10, thereby obtaining low-humidity water electrolysis hydrogen gas. The heat exchanger 21 performs heat exchange using cooling water 22, thereby lowering the dew point of the wet water electrolysis hydrogen gas 20. The obtained low-humidity water electrolysis hydrogen gas is sent to the flow dividing valve 28.

[0013] <Flow Diverter Valve 28> The flow dividing valve 28 is disposed between the heat exchanger 21 and the absorber 30, and distributes a portion of the low-humidity water electrolysis hydrogen gas to the absorber 30 side, and distributes the remainder to the regenerator 34 side. The low-humidity water electrolysis gas discharged to the regenerator 34 side serves as regenerator dry hydrogen gas 40. The distribution ratio of the low-humidity water electrolysis hydrogen gas 20 can be appropriately set to a desired value.

[0014] The low-humidity water electrolysis hydrogen gas discharged from the flow dividing valve 28 to the absorber 30 side is sent to the regulator 29. The low-humidity water electrolysis hydrogen gas discharged from the flow dividing valve 28 to the regenerator 34 side is sent to the regenerator 34 via the flow meter 43.

[0015] <Regulator 29> The regulator 29 is disposed between the diverter valve 28 and the absorber 30, and serves to reduce the pressure of the low-humidity water electrolysis hydrogen gas discharged from the diverter valve 28 toward the absorber 30. The low-humidity water electrolysis hydrogen gas discharged from the regulator 29 is sent to the absorber 30. At this time, the low-humidity water electrolysis hydrogen gas is joined with the wet regeneration hydrogen gas 45. Therefore, the regulator 29 reduces the pressure of the low-humidity water electrolysis hydrogen gas to the same level as the wet regeneration hydrogen gas 45.

[0016] <Absorber 30> The absorber 30 brings the low-humidity water electrolysis hydrogen gas (or a mixed gas of low-humidity water electrolysis hydrogen gas and wet regenerating hydrogen gas 45) into contact with an absorbing liquid (dry absorbing liquid 38) to obtain the dry water electrolysis hydrogen gas 26 with reduced humidity and the 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 26 and the wet absorbing liquid 37 are separated into gas and liquid.

[0017] 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.

[0018] As shown in Fig. 1, the absorbing liquid (dry absorbing liquid 38) is introduced from the top of the absorber 30, and the low-humidity water electrolysis hydrogen gas is introduced from the bottom of the absorber 30. They come into contact with each other inside the absorber 30. The absorbing liquid inside 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.

[0019] Water vapor in the low humidity water electrolysis hydrogen gas is absorbed by the absorbing liquid and reduced. Hydrogen with reduced moisture (dry water electrolysis hydrogen gas 26) is introduced into the trap 24 from the top of the absorber 30. The trap 24 can remove the absorbing liquid entrained in 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 storage device 27. 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.

[0020] <Regenerator 34> The regenerator 34 brings the wet absorption liquid 37 into contact with dry hydrogen gas for regeneration 40 (low-humidity water electrolysis hydrogen gas) to obtain a dry absorption liquid 38 with a reduced moisture content and wet hydrogen gas for regeneration 45 with increased humidity.

[0021] 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.

[0022] 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. Then, 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.

[0023] 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.

[0024] The obtained wet regeneration hydrogen gas 45 exchanges heat with cooling water 42 in the heat exchanger 41 to lower the dew point, and then merges with the low humidity water electrolysis hydrogen gas discharged from the regulator 29.

[0025] Here, the low humidity water electrolysis hydrogen gas discharged from the regulator 29 is decompressed to a pressure approximately equal to that of the wet regeneration hydrogen gas 45, so the pressure in the regenerator 34 is higher than the pressure at the inlet of the absorber 30. Therefore, the wet regeneration hydrogen gas 45 moves from the regenerator 34 to the absorber 30, driven by the pressure difference.

[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 pressure in the regenerator 34 is higher than the pressure at the inlet of the absorber 30, and the pressure difference between these two is used as a driving force to move the wet regeneration hydrogen gas 45 from the regenerator 34 toward the absorber 30. Therefore, no hydrogen boost pump is required for the movement of the wet regeneration hydrogen gas 45. Therefore, the dry water electrolysis hydrogen gas production apparatus 1 can reduce costs.

[0028] 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 does not require a hydrogen boost pump for the movement of the wet regenerating hydrogen gas 45, which allows for cost reduction.

[0029] [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, a water electrolysis step of electrolyzing water to generate wet water electrolysis hydrogen gas containing hydrogen and water vapor, a heat exchange step of lowering the dew point of the wet water electrolysis hydrogen gas discharged from the water electrolysis step to obtain low-humidity water electrolysis hydrogen gas, an absorption step of contacting the low-humidity water electrolysis hydrogen gas with an absorbing solution to obtain dry water electrolysis hydrogen gas with reduced humidity and a wet absorbing solution that selectively absorbs water vapor, a regeneration step of contacting the wet absorbing solution with dry hydrogen gas for regeneration to obtain a dry absorbing solution with reduced moisture content and a wet hydrogen gas for regeneration with increased humidity, a liquid delivery step of delivering the wet absorbing solution to the regeneration step, and a heat exchange step and an absorption step performed between the water electrolysis step and the water electrolysis step. the dry hydrogen gas for regeneration is low-humidity water electrolysis hydrogen gas, the pressure of the dry hydrogen gas for regeneration in the regeneration step is higher than the pressure of the wet water electrolysis hydrogen gas after pressure reduction in the pressure reduction step, and the wet regeneration hydrogen gas discharged from the regenerator step is merged with the wet water electrolysis hydrogen gas after pressure reduction in the pressure reduction step using the pressure difference as a driving force.

[0030] The dry water electrolysis hydrogen gas production method of the present disclosure can be carried out using the above-mentioned dry water electrolysis hydrogen gas production device. According to the dry water electrolysis hydrogen gas production method of the present disclosure, a hydrogen boost pump is not required for the movement of the wet regenerating hydrogen gas, so costs can be reduced. The details of the dry water electrolysis hydrogen gas production method of the present disclosure have been described above, so a detailed description will be omitted here. [Explanation of symbols]

[0031] 1. Water electrolysis hydrogen gas production equipment 10 Water electrolysis equipment 20 Wet water electrolysis hydrogen gas 21 Heat exchanger 22 Cooling water 23 Flow control meter 24 Trap 25 Dew point meter 26 Dry water electrolysis hydrogen gas 27 Storage Device 28 Diverter valve 29 Regulator 30 Absorber 31 Flowmeter 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 41 Heat exchanger 42 Cooling water 43 Flow meter 44 Drain 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; a heat exchanger for lowering the dew point of the wet water electrolysis hydrogen gas discharged from the water electrolysis apparatus to obtain low-humidity water electrolysis hydrogen gas; an absorber that brings the low-humidity water electrolysis hydrogen gas into contact with an absorbing solution to obtain a dry water electrolysis hydrogen gas having a reduced humidity and a wet absorbing solution that selectively absorbs the water vapor; 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; a dividing valve disposed between the heat exchanger and the absorber for allowing a portion of the low humidity water electrolysis hydrogen gas to flow to the absorber side and the remainder to flow to the regenerator side; a regulator disposed between the diverter valve and the absorber, for reducing the pressure of the low humidity water electrolysis hydrogen gas discharged from the diverter valve toward the absorber; the dry hydrogen gas for regeneration is the low humidity water electrolysis hydrogen gas, The pressure of the regenerator is higher than the pressure at the inlet of the absorber, and the wet regenerating hydrogen gas moves from the regenerator to the absorber using the pressure difference as a driving force. Dry water electrolysis hydrogen gas production equipment.

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