Gas separation reflux device for hydrogen production by water electrolysis

Abstract

The utility model discloses a gas separation reflux device for hydrogen production by water electrolysis, and belongs to the field of hydrogen production by water electrolysis. Comprising a switch valve and a first needle valve used for adjusting the flow rate of liquid, the switch valve and the first needle valve are sequentially connected through a communicating pipe, a diaphragm is connected beside the switch valve, and the diameter of the diaphragm is larger than that of the communicating pipe used for connecting all parts. And a switch valve is arranged at the rear end of the diaphragm and is used for controlling the backflow of the electrolyte. The diameter of the diaphragm is 1-5 cm larger than that of the communicating pipe. The rear end of the first needle valve is connected with a second needle valve. The needle hole diameter of the first needle valve and the needle hole diameter of the second needle valve can be adjusted to be 0.3-0.8 mm, and the first needle valve and the second needle valve are used for further controlling the backflow speed of the electrolyte. The gas separation reflux device for hydrogen production through water electrolysis can achieve the effects of being simple in structure and effectively reducing the concentration of hydrogen in oxygen in a post-treatment system.

Description

Technical Field

[0001] This utility model relates to hydrogen production by water electrolysis, and more particularly to a gas-barrier reflux device for hydrogen production by water electrolysis. Background Technology

[0002] Electrolysis of water to produce hydrogen is a technology that directly converts electrical energy into hydrogen energy, offering advantages such as high conversion efficiency, no pollution, and no carbon emissions. Currently, anion exchange membrane electrolyzers (AEM) and proton exchange membrane electrolyzers (PEM) widely adopt a single-sided circulating electrolyte mode at the anode. However, due to the effects of electric drag force and osmosis, a large amount of electrolyte on the cathode side of the electrolyzer also needs to be returned to the anode side or the electrolyzer. In existing differential pressure designs, the hydrogen and oxygen towers of the post-treatment system are directly connected by pipelines. When the switching valve is activated, because the pressure on the hydrogen side is slightly higher than that on the oxygen side, the electrolyte on the hydrogen side will directly flow back to the oxygen side. However, under high pressure, hydrogen bubbles are small, leading to a large amount of hydrogen dissolving in the electrolyte, resulting in a high hydrogen concentration in the oxygen and even posing a safety hazard of explosion.

[0003] In the post-treatment stage of AEM and PEM water electrolysis systems, the electrolyte on the hydrogen side flows back to the oxygen side through separation or circulation paths, leading to an abnormally high hydrogen concentration in the oxygen. This phenomenon mainly stems from design flaws in the post-treatment system. For example, the gas-liquid separator may be inefficient, failing to effectively trap dissolved oxygen or microbubbles; since most AEM and PEM water electrolysis systems are differential pressure designs, the hydrogen side pressure is high, and the reflux rate is fast, causing the hydrogen-containing electrolyte to enter the oxygen side too quickly, resulting in an excessively high hydrogen concentration in the oxygen of the electrolyzer.

[0004] Currently, some manufacturers use the method of adding small buffer tanks for secondary separation to solve the above problems, but this solution makes the entire post-processing framework structure relatively bulky. Summary of the Invention

[0005] Purpose of the utility model: The purpose of this utility model is to provide a gas-barrier reflux device for hydrogen production by water electrolysis that has a simple structure and effectively reduces the hydrogen concentration in oxygen in the post-treatment system.

[0006] Technical solution: The gas-barrier reflux device for hydrogen production by water electrolysis described in this utility model includes a switch valve and a first needle valve for adjusting the liquid flow rate, which are connected in sequence through a connecting pipe. A diaphragm is connected next to the switch valve, and the diameter of the diaphragm is larger than the diameter of the connecting pipe for connecting the various components.

[0007] Preferably, the diameter of the diaphragm is 1-5 cm larger than the diameter of the connecting tube; more preferably, the diameter of the diaphragm is 2 cm larger than the diameter of the connecting tube.

[0008] Preferably, a second needle valve is connected to the rear end of the first needle valve to control the return flow rate of the electrolyte.

[0009] Preferably, the diaphragm is an alkaline PPS diaphragm, which has both gas-blocking and liquid-permeable properties, allowing liquid to pass through while preventing gas from passing through, thus completing preliminary gas-liquid separation. The alkaline PPS diaphragm has good chemical stability and corrosion resistance, and can withstand the corrosion of the electrolyte. The alkaline PPS diaphragm has a microporous structure with a pore size ranging from 0.2 to 0.4 micrometers, which can block hydrogen bubbles from passing through but allows electrolyte to pass through. The alkaline PPS diaphragm is placed in the electrolyte flow channel of the gas-blocking reflux device to provide preliminary gas blocking for the electrolyte.

[0010] Preferably, a switching valve is provided at the rear end of the diaphragm to control the backflow of the electrolyte.

[0011] Preferably, the needle diameter of the first needle valve and the second needle valve can be adjusted to 0.3-0.8 mm to further control the reflux rate of the electrolyte.

[0012] Preferably, a third needle valve is connected to the rear end of the second needle valve to control the return flow rate of the electrolyte.

[0013] Beneficial effects: Compared with the prior art, this utility model has the following advantages: (1) The device uses an alkaline PPS diaphragm for initial gas blocking, which can greatly reduce the return of hydrogen-containing electrolyte to the oxygen side and reduce the safety hazard of excessive hydrogen concentration in oxygen; (2) The device is equipped with a switch valve and two needle valves. By adjusting the opening of the switch valve and controlling the needle diameter of the needle valve, the speed of the return of hydrogen-containing electrolyte to the oxygen side can be reduced, thus reducing the safety hazard of excessive hydrogen concentration in oxygen and reducing equipment risk; (3) By setting an alkaline PPS diaphragm and needle valve in the return path of the electrolyte, the device avoids the design of adding a small buffer tank in the traditional structure. The whole device structure is compact and simple, suitable for small and medium-sized post-processing frames, and avoids the problem of the bulky structure of the whole post-processing frame caused by adding a buffer tank. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall appearance of the present utility model;

[0015] Figure 2 This is a schematic diagram showing the connection relationship between the device described in this utility model and the hydrogen tower and oxygen tower during use. Detailed Implementation

[0016] The technical solution of this utility model will be further described below with reference to the embodiments.

[0017] Example 1

[0018] As shown in the figure, the gas-barrier reflux device for hydrogen production by water electrolysis of this utility model includes a diaphragm 2, a switching valve 3, a first needle valve 4 and a second needle valve 5 for adjusting the liquid flow rate, which are connected in sequence through a connecting pipe 1. The diameter of the diaphragm 2 is larger than the diameter of the connecting pipe 1 used to connect the various components.

[0019] The device is equipped with a double needle valve after the switching valve. The needle diameter of the double needle valve is adjustable to further control the electrolyte reflux rate.

[0020] An electrolytic cell includes a cathode side and an anode side, with an electrolyte circulation system located on the anode side. For example... Figure 2 As shown, the gas-blocking reflux device of this invention is installed between the cathode-side hydrogen tower and the anode-side oxygen tower to control the rate at which the electrolyte flows back from the cathode side to the anode side. Firstly, utilizing the property of the alkaline PPS membrane that can block gas but transmit electrolyte, hydrogen reflux into the oxygen tower is largely prevented in the first step. Secondly, the electrolyte reflux is controlled by a switching valve. Through a double-needle valve design, the reflux rate of the electrolyte is minimized, allowing hydrogen and electrolyte to separate in the hydrogen tower, thereby ensuring that the hydrogen content in the oxygen of the equipment remains within a low range, meeting safe production conditions.

[0021] In this embodiment, the diameter of the connecting pipe is 2cm.

[0022] The alkaline PPS diaphragm is made of polyphenylene sulfide (PPS) material and can withstand corrosion from a 30 wt% potassium hydroxide solution. The PPS diaphragm is flange-sealed and is circular with a diameter of 4 cm.

[0023] By fully opening the needle hole of the first needle valve and adjusting the needle hole diameter of the second needle valve to about 0.5 mm, the rate at which the hydrogen-containing electrolyte flows back to the oxygen side can be reduced to 0.2-1 liters / minute.

[0024] According to the oxygen-hydrogen concentration analyzer, the oxygen-hydrogen concentration in the 5 standard cubic meter post-treatment system can be reduced to about 0.6%.

[0025] Example 2

[0026] The similarities between this embodiment and Embodiment 1 will not be repeated here. The difference is that the diaphragm is a circle with a diameter of 6 cm.

[0027] According to the oxygen-hydrogen concentration analyzer, the oxygen-hydrogen concentration in the post-treatment system of small standard units can be reduced to about 0.5%.

[0028] Example 3

[0029] The similarities between this embodiment and Embodiment 1 will not be repeated here. The difference is that the diaphragm is a circle with a diameter of 6 cm.

[0030] Adjusting the orifice diameter of both the first and second needle valves to approximately 0.5 mm can reduce the rate at which the hydrogen-containing electrolyte flows back to the oxygen side to 0.1-0.5 L / min. Using an oxygen-hydrogen concentration analyzer, it can be determined that in a small-scale post-treatment system, the hydrogen concentration in the oxygen can be reduced to approximately 0.2%.

[0031] Comparative Example 1

[0032] The similarities between this embodiment and Embodiment 1 will not be repeated here. The difference is that no diaphragm is provided.

[0033] By fully opening the needle hole of the first needle valve and adjusting the needle hole diameter of the second needle valve to about 0.5 mm, the rate at which the hydrogen-containing electrolyte flows back to the oxygen side can be reduced to 0.2-1 liters / minute.

[0034] According to the oxygen-hydrogen concentration analyzer, the hydrogen concentration in the oxygen in the post-treatment system of the small standard is about 1%, and the liquid level control is unstable.

Claims

1. A backflow device for electrolysis of water for hydrogen production, comprising a switching valve (3) and a first needle valve (4) for adjusting the flow rate of liquid connected in series through a communication pipe (1), characterized in that, A diaphragm (2) is connected beside the switch valve (3), and the diameter of the diaphragm (2) is larger than that of the communication pipe (1) for connecting each part.

2. The gas barrier flow device for hydrogen production by water electrolysis according to claim 1, characterized in that, The diameter of the diaphragm (2) is 1-5 cm larger than that of the communication pipe (1).

3. The gas barrier flowback device for hydrogen production by electrolysis of water of claim 1, wherein, The diameter of the diaphragm (2) is 2 cm larger than that of the communication pipe (1).

4. The gas barrier flowback device for hydrogen production by water electrolysis of claim 1, wherein, The second needle valve (5) is connected at the rear end of the first needle valve (4).

5. The gas barrier flow device for hydrogen production by water electrolysis according to claim 1, characterized in that, The diaphragm (2) is an alkaline PPS diaphragm with air resistance and liquid permeability.

6. The gas barrier flow device for hydrogen production by water electrolysis according to claim 1, characterized in that, The switch valve (3) is arranged at the rear end of the diaphragm (2).

7. The gas barrier flow device for hydrogen production by water electrolysis according to claim 4, characterized in that, The needle hole diameter of the first needle valve (4) and the second needle valve (5) can be adjusted to 0.3-0.8 mm.

8. The gas barrier flow device for hydrogen production by water electrolysis according to claim 4, characterized in that, The third needle valve is connected at the rear end of the second needle valve (5).

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