Alkali system for water electrolysis hydrogen production system

Abstract

The utility model discloses a water-alkali system for an electrolytic water hydrogen production system, which comprises a water replenishing system, an alkali preparation system, a water replenishing valve group and a water-alkali tank, a partition plate is arranged in the water-alkali tank and divides the water-alkali tank into a pure water tank and an alkali liquor tank, a communicating pipe is arranged at the bottoms of the pure water tank and the alkali liquor tank, a communicating valve is arranged on the communicating pipe, and the communicating valve is connected with the water replenishing system. The pure water tank is communicated with the water replenishing system, and the alkali liquor tank is respectively communicated with the water replenishing system and the alkali preparation system; a caustic soda flake adding port, a water supplementing port, an alkali liquor outlet, an alkali liquor inlet, a first drain outlet and a first liquid level meter are arranged on one side of the alkali liquor box; and a pure water replenishing port, a pure water outlet, a second drain outlet, a pure water backflow port and a second liquid level meter are arranged on the side of the pure water tank. The device can meet the operation and use requirements of alkali preparation, normal operation water replenishing and shutdown alkali removal of a water electrolysis hydrogen production system, and meanwhile, the volume of the alkali liquor box can be reduced, so that the equipment investment and the occupied area are reduced.

Description

Technical Field

[0001] The utility model relates to the field of water electrolysis hydrogen production, in particular to a water alkali system used in a water electrolysis hydrogen production system. Background Art

[0002] According to the GGII "China Water Electrolysis Hydrogen Production Project Database", as of May 2023, the total hydrogen production scale of domestic water electrolysis hydrogen production projects under construction and planning exceeds 19GW, of which the total hydrogen production scale of green hydrogen projects under construction exceeds 2.8GW. At present, the alkaline water electrolysis hydrogen production system is the mainstream technology of water electrolysis hydrogen production system, and its equipment market share accounts for more than 95% of domestic water electrolysis hydrogen production projects. Alkaline water electrolysis hydrogen production systems mostly use pure water as raw material and 30% KOH solution as electrolyte. Therefore, the alkali preparation system and pure water replenishment system are also important components of the water electrolysis hydrogen production system. Before the operation of the water electrolysis hydrogen production system, alkali solution must be configured, and alkali withdrawal operation must be performed when it is shut down. The alkali solution in the electrolytic cell and separation system is returned to the alkali solution tank for recovery. The specification requires that the volume of the raw water storage tank should not be less than the raw water consumption of 8h, and the volume of the alkali solution tank should be greater than the sum of the total volume of each water electrolysis hydrogen production device and the alkali solution pipeline. According to calculations, the gas production capacity is 1000Nm 3 / h electrolysis water system, a set of 8m 3 Pure water tank and a set of 20m 3 Alkali liquid tank. For projects requiring a large total gas production of the electrolytic cell, the required water replenishment and alkali preparation system has a larger capacity, and the overall system has problems such as large footprint and high investment cost. Utility Model Content

[0003] Purpose of the utility model: The purpose of the utility model is to provide a dual-acting water alkali system which combines the alkali preparation system and the water replenishment system into one in the electrolysis water hydrogen production system, so as to reduce the volume of the pure water tank and the alkali liquid tank, thereby reducing the floor space and investment cost of the pure water tank and the alkali liquid tank.

[0004] Technical solution: The utility model discloses a water alkali system for a water electrolysis hydrogen production system, comprising a water replenishment system, an alkali preparation system and a water replenishment valve group, and also comprising a water alkali tank, wherein a partition is arranged in the water alkali tank, and the partition divides the water alkali tank into a pure water tank and an alkali liquid tank, and connecting pipes are arranged at the bottom of the pure water tank and the alkali liquid tank, and a connecting valve is arranged on the connecting pipe, the pure water tank is connected with the water replenishment system, and the alkali liquid tank is respectively connected with the water replenishment system and the alkali preparation system; the alkali liquid tank side is provided with a caustic soda flake addition inlet, a water replenishment inlet, an alkali liquid outlet, an alkali liquid inlet, a first sewage outlet and a first liquid level gauge; the pure water tank side is provided with a pure water replenishment inlet, a pure water outlet, a second sewage outlet and a second liquid level gauge.

[0005] Furthermore, the alkali solution box is provided with an alkali solution heating device and a thermometer.

[0006] Furthermore, the alkali liquid outlet on the alkali liquid tank side is connected to an inlet pipeline equipped with an alkali liquid circulation pump, the alkali liquid inlet is connected to an outlet pipeline equipped with an alkali liquid circulation pump, and the water replenishment port is connected to a water replenishment system.

[0007] Furthermore, the pure water replenishment port on the pure water tank side includes a first pure water replenishment port and a second pure water replenishment port, the first pure water replenishment port is connected to the replenishment system, the pure water outlet is connected to the hydrogen-alkali separator replenishment port pipeline, the second pure water replenishment port is connected to the dehydrogenation alkali separator replenishment port pipeline and is provided with a pure water pump outlet reflux valve.

[0008] Furthermore, a first pure water pump and a second pure water pump are connected in parallel to the water replenishment pipe of the dehydrogenation alkali separator.

[0009] Furthermore, the partition is detachably connected to the inner wall of the water alkali box.

[0010] Furthermore, the water replenishment system is provided with a water replenishment flow meter.

[0011] Furthermore, a first water replenishment pneumatic valve and a first water replenishment manual valve are provided on the water replenishment port and the water replenishment system connecting pipeline, and a second water replenishment pneumatic valve and a second water replenishment manual valve are provided on the first pure water replenishment port and the water replenishment system connecting pipeline.

[0012] Furthermore, a first pure water pump inlet manual valve and a first pure water pump inlet filter are provided on the pipeline connecting the first pure water pump to the pure water outlet, and a first pure water pump outlet check valve and a first pure water pump outlet manual valve are provided on the pipeline connecting the first pure water pump to the water replenishment port of the hydrogen-alkali separator; a second pure water pump inlet manual valve and a second pure water pump inlet filter are provided on the pipeline connecting the second pure water pump to the pure water outlet, and a second pure water pump outlet check valve and a second pure water pump outlet manual valve are provided on the pipeline connecting the second pure water pump to the water replenishment port of the hydrogen-alkali separator.

[0013] Furthermore, a flow meter is also provided on the alkali liquid tank side.

[0014] Beneficial effects: Compared with the prior art, the utility model has the following advantages: the utility model can meet the operational requirements of alkali preparation, water replenishment during normal operation, and alkali withdrawal during shutdown of the water electrolysis hydrogen production system, and at the same time, the volume of the alkali liquid tank can be reduced, thereby reducing equipment investment and floor space. In addition, according to the system use requirements, the heating device of the alkali liquid tank can be selectively turned on to preheat the alkali liquid before the water electrolysis system is put into operation, thereby increasing the initial temperature of the alkali liquid and reducing the system cold start time. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the system structure of the utility model. DETAILED DESCRIPTION

[0016] The technical solution of the utility model is further described below in conjunction with the accompanying drawings.

[0017] As shown in the figure, the utility model provides a water alkali system for a water electrolysis hydrogen production system, including a water replenishment system, an alkali preparation system and a water replenishment valve group, and also includes a water alkali tank, a partition 1 is provided in the water alkali tank, the partition 1 is detachably connected to the inner wall of the water alkali tank, the partition 1 divides the water alkali tank into a pure water tank 2 and an alkali liquid tank 3, the bottom of the pure water tank 2 and the alkali liquid tank 3 are respectively provided with a first opening 35 and a second opening 36, the first opening 35 and the second opening 36 are connected, a connecting valve 4 is provided on the connecting pipe, the pure water tank 2 is connected with the water replenishment system, and the alkali liquid tank 3 is respectively connected with the water replenishment system and the alkali liquid tank 3; the alkali flake addition port 5, the water replenishment port 17, the alkali liquid outlet 6, the alkali liquid inlet 7, the first sewage outlet 8 and the first liquid level gauge 9 are provided on the alkali liquid tank side; the pure water water replenishment port, the pure water outlet 10, the second sewage outlet 11 and the second liquid level gauge 12 are provided on the pure water tank 2 side, and the second liquid level gauge 12 is a magnetic flap liquid level gauge. The alkali liquid tank 3 is provided with an alkali liquid heating device 13 and a thermometer 14. The alkali liquid outlet on the alkali liquid tank 3 side is connected to the inlet pipe 15 equipped with an alkali liquid circulation pump, the alkali liquid inlet is connected to the outlet pipe 16 equipped with the alkali liquid circulation pump, and the water replenishment port 17 is connected to the water replenishment system. The pure water replenishment port on the pure water tank 2 side includes a first pure water replenishment port 18 and a second pure water replenishment port, the first pure water replenishment port 18 is connected to the water replenishment system, the pure water outlet 10 is connected to the hydrogen-alkali separator replenishment port pipeline, the second pure water replenishment port is connected to the hydrogen-alkali separator replenishment port pipeline and is provided with a pure water pump outlet reflux valve 19. The first pure water pump 20 and the second pure water pump 21 are connected in parallel to the water supply port pipeline of the dehydrogenation alkali separator. The first pure water pump 20 is connected to the pure water outlet 10 by a first pure water pump inlet manual valve 27 and a first pure water pump inlet filter 28. The first pure water pump 20 is connected to the water supply port of the hydrogen-alkali separator by a first pure water pump outlet check valve 29 and a first pure water pump outlet manual valve 30. The second pure water pump 21 is connected to the pure water outlet 10 by a second pure water pump inlet manual valve 31 and a second pure water pump inlet filter 32. The second pure water pump 21 is connected to the water supply port of the hydrogen-alkali separator by a second pure water pump outlet check valve 33 and a second pure water pump outlet manual valve 34. The water supply system is provided with a water supply flowmeter 22. The water replenishment port 17 and the water replenishment system connecting pipe are provided with a first water replenishment pneumatic valve 23 and a first water replenishment manual valve 24, and the first pure water replenishment port 18 and the water replenishment system connecting pipe are provided with a second water replenishment pneumatic valve 25 and a second water replenishment manual valve 26. A flow meter is also provided on the alkali liquid tank side.

[0018] When 30% alkali solution is required, 0.3M KOH raw material is manually poured in according to the total alkali solution mass M to be configured, and then the water replenishment pneumatic valve of the alkali solution tank is opened, and 0.7M pure water is added through the flow meter display or the magnetic flap level meter conversion, and the connecting valve between the pure water tank side and the alkali solution tank side is opened, so that the 30% concentration KOH solution of the total mass M is stored in the water alkali tanks on both sides. At the same time, the electric heating device on the alkali solution tank side can be turned on to preheat the alkali solution, saving the startup time of the electrolytic cell. By using this type of water alkali tank, the 20 cubic alkali solution tank of the 1000Nm3 / h electrolytic water system can be reduced to 12 cubic meters.

[0019] When the electrolysis water system is operating normally, the alkali liquid in the alkali liquid tank has been pumped into the electrolytic cell and the separation system equipment and pipelines. At this time, you only need to close the connecting valves on the water tank side and the alkali liquid tank side, and only use the volume on the pure water tank side. Replenish the pure water tank through the pure water tank replenishment switch valve and the pure water tank side liquid level gauge, and then replenish the raw water to the electrolysis water system through the replenishment pump. At this time, the alkali liquid tank side is empty and can be used as a system backup tank.

[0020] When the electrolytic water system needs to be de-alkalied, the pure water on the pure water tank side can be emptied first, and then the connecting valve can be opened to use both sides as alkali storage tanks. The alkali in the electrolytic cell and separation system pipeline can be discharged to the water alkali tank for storage through the alkali circulation pump de-alkali pipeline. Before the next electrolytic water system is put into operation, the alkali can be preheated by turning on the heating device on the alkali tank side, thereby reducing the cold start time of the electrolytic water system.

Claims

1. A water alkali system for a water electrolysis hydrogen production system, comprising a water replenishment system, an alkali preparation system and a water replenishment valve group, characterized in that: The invention also comprises a water alkali tank, wherein a partition (1) is provided inside the water alkali tank, wherein the partition (1) divides the water alkali tank into a pure water tank (2) and an alkali liquid tank (3), wherein a connecting pipe is provided at the bottom of the pure water tank (2) and the alkali liquid tank (3), wherein a connecting valve (4) is provided on the connecting pipe, wherein the pure water tank (2) is connected to a water replenishment system, and the alkali liquid tank (3) is connected to a water replenishment system and an alkali preparation system respectively; wherein the alkali liquid tank side is provided with a caustic soda flake addition inlet (5), a water replenishment inlet (17), an alkali liquid outlet (6), an alkali liquid inlet (7), a first sewage outlet (8) and a first liquid level gauge (9); wherein the pure water tank (2) side is provided with a pure water replenishment inlet, a pure water outlet (10), a second sewage outlet (11) and a second liquid level gauge (12).

2. The water-alkali system for a water electrolysis hydrogen production system according to claim 1, characterized in that: An alkali solution heating device (13) and a thermometer (14) are arranged in the alkali solution box.

3. The water-alkali system for a water electrolysis hydrogen production system according to claim 1, characterized in that: The alkali liquid outlet (6) on the alkali liquid tank (3) side is connected to an inlet pipeline (15) equipped with an alkali liquid circulation pump, the alkali liquid inlet (7) is connected to an outlet pipeline (16) equipped with an alkali liquid circulation pump, and the water replenishment port (17) is connected to a water replenishment system.

4. The water-alkali system for a water electrolysis hydrogen production system according to claim 2, characterized in that: The pure water replenishment port on the pure water tank (2) side comprises a first pure water replenishment port (18) and a second pure water replenishment port, wherein the first pure water replenishment port (18) is connected to the replenishment system, the pure water outlet (10) is connected to the hydrogen-alkali separator replenishment port pipeline, and the second pure water replenishment port is connected to the dehydrogenation alkali separator replenishment port pipeline and is provided with a pure water pump outlet reflux valve (19).

5. The water-alkali system for a water electrolysis hydrogen production system according to claim 4, characterized in that: A first pure water pump (20) and a second pure water pump (21) are connected in parallel to the water replenishment pipe of the hydrogen-alkali separator.

6. The water-alkali system for a water electrolysis hydrogen production system according to claim 1, characterized in that: The partition (1) is detachably connected to the inner wall of the water alkali box.

7. The water-alkali system for a water electrolysis hydrogen production system according to claim 1, characterized in that: The water replenishment system is provided with a water replenishment flow meter (22).

8. The water-alkali system for a water electrolysis hydrogen production system according to claim 4, characterized in that: The water replenishment port (17) and the water replenishment system connecting pipeline are provided with a first water replenishment pneumatic valve (23) and a first water replenishment manual valve (24), and the first pure water replenishment port (18) and the water replenishment system connecting pipeline are provided with a second water replenishment pneumatic valve (25) and a second water replenishment manual valve (26).

9. The water-alkali system for a water electrolysis hydrogen production system according to claim 5, characterized in that: A first pure water pump inlet manual valve (27) and a first pure water pump inlet filter (28) are provided on the pipeline connecting the first pure water pump (20) with the pure water outlet (10); a first pure water pump outlet check valve (29) and a first pure water pump outlet manual valve (30) are provided on the pipeline connecting the first pure water pump (20) with the water replenishment port of the hydrogen-alkali separator; a second pure water pump inlet manual valve (31) and a second pure water pump inlet filter (32) are provided on the pipeline connecting the second pure water pump (21) with the pure water outlet (10); a second pure water pump outlet check valve (33) and a second pure water pump outlet manual valve (34) are provided on the pipeline connecting the second pure water pump (21) with the water replenishment port of the hydrogen-alkali separator.

10. The water-alkali system for a water electrolysis hydrogen production system according to claim 1, characterized in that: A flow meter is also provided on the alkali liquid tank side.

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