Series functional lye tank and alkaline water electrolysis hydrogen production system with the lye tank

Abstract

The present invention relates to a series-connected functional lye tank and an alkaline water electrolysis hydrogen production system with the lye tank. The series-connected functional lye tank includes at least three serially connected lye tanks; among them, the middle lye tank is a functional lye tank for treating dissolved gases in the electrolyte. Compared with the prior art, through the design of the series-connected functional lye tank, the present invention significantly reduces the concentration of impurity gases dissolved in the lye entering the electrolytic cell through the low-pressure degassing process, effectively improving the safety of the electrolytic hydrogen production system.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen production by alkaline water electrolysis, and more particularly to a series-connected functional alkaline liquid tank and an alkaline water electrolysis hydrogen production system with the alkaline liquid tank. Background Art

[0002] The development of hydrogen energy technology meets the major strategic needs of the country and is one of the important paths to achieve "carbon peak and carbon neutrality". The development of hydrogen production technology is a prerequisite for the wide application of hydrogen energy. Electrolytic water hydrogen production is one of the most commonly used hydrogen production technologies at present. Among them, the alkaline water electrolysis hydrogen production technology is relatively mature and has been commercialized. With the continuous increase in the demand for hydrogen, the electrolytic hydrogen production system is continuously enlarged, and the hydrogen production capacity of a single electrolytic cell has exceeded 1200 Nm 3 / h.

[0003] In order to further improve the hydrogen production capacity of the hydrogen production system, a combined electrolytic hydrogen production system formed by parallel connection of multiple electrolytic cells has gradually emerged. These systems usually share the alkaline liquid circulation, gas-liquid separation and gas purification systems, simplify the complexity of the electrolytic hydrogen production system, and reduce the equipment cost. During the alkaline liquid circulation process, due to the dissolution characteristics of gases, the alkaline water flowing out of the alkaline liquid tank into the electrolytic cell is mixed with mixed gases. When the concentration of impurity gases inside the electrolytic cell is too high, there are potential safety hazards.

[0004] Therefore, how to reduce the concentration of dissolved gases in the alkaline liquid entering the electrolytic cell is crucial for improving the safety of the electrolytic hydrogen production system. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned existing technologies and provide a series-connected functional alkaline liquid tank and an alkaline water electrolysis hydrogen production system with the alkaline liquid tank. Through the design of the series-connected functional alkaline tank, the concentration of dissolved impurity gases in the alkaline liquid entering the electrolytic cell is significantly reduced through the low-pressure degassing process, effectively improving the safety of the electrolytic hydrogen production system.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] According to the first aspect of the present invention, there is provided a series-connected functional alkaline liquid tank, including at least 3 series-connected alkaline liquid tanks; wherein, the middle alkaline liquid tank is a functional alkaline liquid tank for treating dissolved gases in the electrolyte.

[0008] Preferably, the number of the series-connected alkaline liquid tanks is 3 to 5.

[0009] Preferably, the functional alkaline liquid tank is externally connected with a vacuum device for performing low-pressure or vacuum treatment on the functional alkaline liquid tank to reduce the concentration of dissolved gases in the alkaline liquid.

[0010] Preferably, a lye heating device with controllable temperature is further provided in the functional lye tank.

[0011] According to a second aspect of the present invention, there is provided an alkaline water electrolysis hydrogen production system, including an electrolyzer, a lye circulation device, a gas-liquid separation device, and a gas purification device. The lye circulation device includes a gas separator, the series-connected functional lye tank according to any one of claims 1-4, a circulation pump, a cooler, a heater, and a filter connected in sequence;

[0012] After the two paths of electrolyte from the combined electrolyzer pass through the gas separator in the lye circulation device, they converge into the series-connected functional lye tank, and then pass through the circulation pump, cooler, heater, and filter in sequence, and are circulated into the combined electrolyzer;

[0013] The gas produced by the decomposition of the combined electrolyzer is connected to the gas-liquid separation device through the gas separator and then connected to the gas purification device.

[0014] Preferably, the combined electrolyzer includes a plurality of electrolyzers connected in series or in parallel.

[0015] Preferably, the gas separator includes a hydrogen-side separator and an oxygen-side separator.

[0016] Preferably, the gas-liquid separation device includes two paths of separation devices, including a hydrogen-side gas-liquid separation device and an oxygen-side gas-liquid separation device.

[0017] Preferably, the hydrogen-side gas-liquid separation device includes a hydrogen-side separator, a hydrogen-side heat exchanger, and a hydrogen-side back pressure valve, and is connected to the hydrogen purification system.

[0018] Preferably, the oxygen-side gas-liquid separation device includes an oxygen-side separator, an oxygen-side heat exchanger, and an oxygen-side back pressure valve, and is connected to the oxygen purification system.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1) The series-connected functional lye tank designed by the present invention can reduce the solubility of hydrogen and oxygen in the lye by reducing the saturated vapor pressure inside the lye tank by using a plurality of series-connected lye tanks instead of the traditional single or no lye tank, reduce the concentration of dissolved hydrogen and oxygen in the lye, ensure that the dissolved hydrogen / oxygen concentration in the reflux lye remains low, and effectively improve the safety of the electrolyzer;

[0021] 2) The present invention significantly reduces the concentration of impurity gases dissolved in the lye entering the electrolyzer through the low-pressure degassing process of the functional lye tank by a vacuum device, and effectively improves the safety of the electrolysis hydrogen production system;

[0022] 3) The present invention can use an alkali solution heating device with a controllable temperature to control foreseeable operating conditions such as the temperature of the alkali solution for the functional alkali solution tank according to the operating state of the electrolytic cell. Description of the Drawings

[0023] Figure 1 It is a schematic structural diagram of the series-connected functional alkali solution tank of the present invention and an alkaline water electrolysis hydrogen production system with this alkali solution tank. Detailed Embodiments

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] Embodiment

[0026] As Figure 1 shown, this embodiment provides a series-connected functional alkali solution tank and an alkaline water electrolysis hydrogen production system with this alkali solution tank. The system includes a combined electrolytic cell, an alkali solution circulation device, a gas-liquid separation device, and a gas purification device. Among them, the alkali solution circulation device includes a gas separator, a series-connected functional alkali solution tank, a circulation pump, a cooler, a heater, and a filter connected in sequence.

[0027] The series-connected functional alkali solution tank includes at least 3 series-connected alkali solution tanks; among them, the middle alkali solution tank is a functional alkali solution tank for treating dissolved gases in the electrolyte solution. The number of the series-connected alkali solution tanks is 3-5.

[0028] The alkali solution tank is the core component in the alkali solution circulation process. In the series-connected functional alkali solution tank, multiple series-connected alkali solution tanks are used to replace the traditional single or no alkali solution tank. In this embodiment, 3 series-connected alkali solution tanks are adopted. The first alkali solution tank mainly mixes the alkali solutions flowing out of the hydrogen separator and the oxygen separator. The alkali solution flows from the first alkali solution tank into the second alkali solution tank, and the second alkali solution tank is subjected to low-pressure / vacuum treatment to reduce the saturated vapor pressure inside the alkali solution tank, reduce the solubility of hydrogen and oxygen in the alkali solution, and reduce the concentration of dissolved hydrogen and oxygen in the alkali solution. The alkali solution in the second alkali solution tank flows into the third alkali solution tank to test the concentration of dissolved hydrogen / oxygen in the alkali solution, ensuring that the reflux alkali solution maintains a low concentration of dissolved hydrogen / oxygen and improving the safety of the electrolytic cell.

[0029] The functional alkali solution tank is externally connected with a vacuum device for performing low-pressure or vacuum treatment on the functional alkali solution tank to reduce the concentration of dissolved gases in the alkali solution.

[0030] The functional lye tank is also provided with a lye heating device with controllable temperature.

[0031] The two-way electrolyte from the combined electrolyzer passes through the gas separator in the lye circulation device, converges into the series-connected functional lye tank, and then sequentially passes through a circulation pump, a cooler, a heater, and a filter, and is circulated into the combined electrolyzer;

[0032] The gas produced by the decomposition of the combined electrolyzer is connected to the gas-liquid separation device through the gas separator and then connected to the gas purification device.

[0033] Among them, the combined electrolyzer is composed of multiple electrolyzers with the same / different hydrogen production capacities combined in series / parallel. In this solution, 5 electrolyzers with different hydrogen production capacities are connected in parallel, and the hydrogen production capacities are 1000 Nm 3 / h, 800 Nm 3 / h, 600 Nm 3 / h, 400 Nm 3 / h, 200 Nm 3 / h. The gas mixture flowing out of the electrolyzer flows into the hydrogen / oxygen separator in parallel.

[0034] The gas-liquid separation device includes two-way separation devices, including a gas-liquid separation device on the hydrogen side and a gas-liquid separation device on the oxygen side. Among them, the gas-liquid separation device on the hydrogen side includes a hydrogen side separator, a hydrogen side heat exchanger, and a hydrogen side back pressure valve, and is connected to the hydrogen purification system; the gas-liquid separation device on the oxygen side includes an oxygen side separator, an oxygen side heat exchanger, and an oxygen side back pressure valve, and is connected to the oxygen purification system.

[0035] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of various equivalent modifications or substitutions within the technical scope disclosed by the present invention, and these modifications or substitutions should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A series-connected functional lye tank, characterized in that, It includes at least 3 serially connected lye tanks; among them, the middle lye tank is a functional lye tank for treating dissolved gases in the electrolyte solution; The functional lye tank is externally connected with a vacuum device for performing low-pressure or vacuum treatment on the functional lye tank to reduce the concentration of dissolved gases in the lye.

2. The series-connected functional lye tank according to claim 1, wherein, The number of the serially connected lye tanks is 3 to 5.

3. The series functional lye tank according to claim 1, characterized in that, The functional lye tank is also provided with a lye heating device with controllable temperature.

4. An alkaline water electrolysis hydrogen production system, comprising a combined electrolyzer, an alkaline solution circulation device, a gas-liquid separation device and a gas purification device, characterized in that, The lye circulation device includes a gas separator, the series-connected functional lye tank according to any one of claims 1-3, a circulation pump, a cooler, a heater, and a filter that are connected in sequence; The two paths of electrolyte solution coming out of the combined electrolytic cell pass through the gas separator in the lye circulation device, then converge to the series-connected functional lye tank, and then sequentially pass through the circulation pump, the cooler, the heater, and the filter, and are circulated into the combined electrolytic cell; The gas produced by the decomposition of the combined electrolytic cell is connected to the gas-liquid separation device through the gas separator and then connected to the gas purification device.

5. The alkaline water electrolysis hydrogen production system according to claim 4, characterized in that, The combined electrolytic cell includes a plurality of serially or parallelly connected electrolytic cells.

6. The alkaline water electrolysis hydrogen production system according to claim 4, characterized in that, The gas separator includes a hydrogen-side separator and an oxygen-side separator.

7. The alkaline water electrolysis hydrogen production system according to claim 4, characterized in that, The gas-liquid separation device includes two paths of separation devices, including a hydrogen-side gas-liquid separation device and an oxygen-side gas-liquid separation device.

8. The alkaline water electrolysis hydrogen production system according to claim 7, characterized in that, The hydrogen-side gas-liquid separation device includes a hydrogen-side separator, a hydrogen-side heat exchanger, and a hydrogen-side back pressure valve, and is connected to the hydrogen purification system.

9. The alkaline water electrolysis hydrogen production system according to claim 7, characterized in that, The oxygen-side gas-liquid separation device includes an oxygen-side separator, an oxygen-side heat exchanger, and an oxygen-side back pressure valve, and is connected to the oxygen purification system.

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