Communicating pipe, gas-liquid separation method thereof and water electrolysis hydrogen production device comprising communicating pipe

Abstract

The invention discloses a communicating pipe, a gas-liquid separation method thereof and a water electrolysis hydrogen production device comprising the communicating pipe. The communicating pipe comprises a main pipeline, a gas capturing pipe and a porous gas guide pipe. The main pipeline is a main body, the air capturing pipes are densely arranged in the main pipeline and are tightly connected with one another, the outer wall of the air capturing pipe on the outermost layer is tightly connected with the inner wall of the main pipeline and is fixed in the main pipeline, a porous air guide pipe is arranged in each air capturing pipe, and the outer wall of each porous air guide pipe is connected with the inner wall of the air capturing pipe through a connecting column; the porous gas guide pipe is fixed in the middle of the gas trapping pipe and keeps a certain distance from the gas trapping pipe, the gas trapping pipe intercepts bubbles in the main pipeline through the hydrophilicity and roughness of the pipeline, small bubbles are fused into large bubbles, and the large bubbles are transported upwards through buoyancy or guided away through the porous gas guide pipe. The gas content of the solution passing through the communicating pipe is greatly reduced, passive gas-liquid separation is achieved, and the situation of hydrogen and oxygen mixing caused by the communicating pipe is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of water electrolysis hydrogen production, and specifically relates to the technical field of gas-liquid separation in water electrolysis hydrogen production equipment, and specifically relates to a connecting pipe, a method for gas-liquid separation thereof, and a water electrolysis hydrogen production device comprising the same. Background Art

[0002] Clean and low-carbon are the development trends of future energy. Hydrogen energy, with its zero emission and high energy characteristics, is considered to be an ideal future energy carrier and has received widespread attention from all over the world. Large-scale and cheap hydrogen production has become one of the key links in the development and utilization of hydrogen energy. In commercial production, the main sources of hydrogen include natural gas, oil, coal and electrolysis. However, as the main source of industrial hydrogen, the production process of fossil fuel reforming hydrogen will emit a large amount of CO2 and other greenhouse gases, causing serious pollution to the environment.

[0003] In contrast, hydrogen production through water electrolysis using renewable energy is an efficient and green way to produce hydrogen. The production process does not emit greenhouse gases, which meets the requirements of low-carbon and green development. In China, alkaline water electrolysis dominates the water electrolysis industry, with relatively mature technology and low equipment cost, and is an important means to achieve large-scale hydrogen production.

[0004] However, in the process of producing hydrogen by alkaline water electrolysis, gas-liquid separation is a key link. The cathode and anode of the electrolyzer produce a mixture of hydrogen, oxygen and alkali solution. The circulating electrolyte leading to the cathode and anode is stored in different tanks. After a long period of operation, the concentration of alkali solution in the cathode tank and the anode tank is inconsistent due to the inconsistent water content consumed by the cathode and anode. It is necessary to use a connecting pipe to connect the alkali solution in the two tanks to eliminate the concentration difference. During the actual operation, the solutions in the two tanks will be periodically exchanged. However, due to the connection of the alkali solution, small bubbles will enter the other tank through the connecting pipe during the exchange of alkali solution, causing the oxygen content in hydrogen and the hydrogen content in oxygen to exceed the standard, which is easy to cause safety hazards. However, the current device does not fully solve the hydrogen-oxygen mixing problem caused by the connecting pipe. The alkali solution circulation pump will circulate the hydrogen / oxygen alkali solution to the electrolyzer, resulting in a decrease in the purity of hydrogen / oxygen in the electrolyzer and an increased risk of explosion.

[0005] In order to solve the above problems, the present invention is proposed. Summary of the invention

[0006] In order to solve the above-mentioned problem of gas crossover caused by the connecting pipe between the cathode alkali solution storage tank and the anode alkali solution storage tank in the water electrolysis device, the present invention provides a new type of pipeline design, which can achieve the separation of tiny bubbles in the solution when the solution in the cathode alkali solution storage tank and the anode alkali solution storage tank is exchanged, thereby realizing the exchange of pure solutions in the two tanks, greatly reducing the gas crossover caused by the connection of the tanks, and improving the purity of hydrogen and oxygen in the electrolyzer.

[0007] The connecting pipe of the present invention comprises a main pipe, an air capture pipe and a porous air guide pipe, wherein the main pipe is the main body, and the air capture pipes are densely arranged inside the main pipe, and the air capture pipes are tightly connected to each other, and the outer wall of the outermost air capture pipe is tightly connected to the inner wall of the main pipe and fixed inside the main pipe, and each air capture pipe has a porous air guide pipe inside, and the outer wall of the porous air guide pipe is connected to the inner wall of the air capture pipe by a connecting column, and the porous air guide pipe is fixed in the middle of the air capture pipe and keeps a certain distance from the air capture pipe, and the air capture pipe intercepts the bubbles in the main pipe by the air affinity and roughness of the pipe itself, and the small bubbles merge into large bubbles, which are transported upward by buoyancy or guided away by the porous air guide pipe, and the gas content of the solution after passing through the connecting pipe is greatly reduced, so as to realize passive gas-liquid separation and reduce the hydrogen-oxygen mixing caused by the connecting pipe.

[0008] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is:

[0009] The first aspect of the present invention provides a connecting pipe, which includes a main pipe 1, an air capture pipe 3, and a porous air guide pipe 6;

[0010] The main pipeline 1 includes a plurality of air-catching tubes 3 inside, each of which has an air-catching tube outer wall 4 and an air-catching tube inner wall 5. The air-catching tube outer walls 4 of adjacent air-catching tubes 3 are fitted to each other (closely attached and fixed), and the air-catching tube outer wall 4 of the air-catching tube 3 located outside is fitted to the main pipeline inner wall 2 of the main pipeline 1 (closely attached and fixed);

[0011] Each of the air catching tubes 3 has a porous air guide tube 6 at its central axis. The porous air guide tube 6 has a porous air guide tube inner wall 10 and a porous air guide tube outer wall 11. The porous air guide tube 6 has a plurality of through holes on its wall that connect the porous air guide tube outer wall 11 with the porous air guide tube inner wall 10.

[0012] Preferably, the porous air guide tube 6 is fixed to the central axis of the air capture tube 3 by a bilaterally symmetrical fixing member 9. Of course, there are many ways to fix the porous air guide tube 6 to the central axis of the middle of the air capture tube 3, including but not limited to fixing it using a fixing member 9. The fixing member 9 can be selected from a connecting column.

[0013] Preferably, the plurality of air-catching tubes 3 are horizontally arranged with the main pipeline 1 , and the plurality of air-catching tubes 3 are gathered in parallel inside the main pipeline 1 .

[0014] Preferably, the main pipeline 1 comprises a first pipeline opening 7 at one end and a second pipeline opening 8 at the other end;

[0015] The outer wall of the main pipe 1 is made of metal material such as steel, and the inner wall 2 of the main pipe is made of alkali corrosion-resistant material such as polytetrafluoroethylene lining, and the inner wall 2 of the main pipe is roughened.

[0016] Preferably, the air capture tube 3 is made of an alkali corrosion-resistant material including but not limited to polytetrafluoroethylene, and the air capture tube outer wall 4 and the air capture tube inner wall 5 are rough surfaces.

[0017] Preferably, there are various connection modes between the plurality of air capture tubes 3, including but not limited to adhesive connection, rope connection, etc.;

[0018] There are many ways to connect the air capture pipe 3 and the main pipeline 1, including but not limited to adhesive connection, rope connection, etc.

[0019] Preferably, the porous air guide tube 6 is made of a corrosion-resistant, gas-friendly material, which may be made by coating or using an integrated material, including but not limited to polytetrafluoroethylene.

[0020] Preferably, the size of the porous air guide tube 6 is smaller than that of the air capture tube 3;

[0021] The through holes on the wall of the porous air duct 6, that is, there are a large number of tiny through holes on the wall of the porous air duct 6. The through holes can be distributed in a variety of ways, including but not limited to random size and uniform size. There are a variety of ways to arrange the through holes, including ordered arrangement and disordered arrangement.

[0022] The second aspect of the present invention provides a method for gas-liquid separation using the connecting pipe according to the first aspect of the present invention, wherein the first pipe opening 7 is an inlet for a gas-liquid mixture, and the second pipe opening 8 is an outlet for a liquid;

[0023] The gas-liquid mixture enters from the first pipe opening 7, and the bubbles in the liquid are adhered to the inner wall 5 of the air catching tube, and are gradually accumulated from small bubbles into large bubbles. The large bubbles accumulated on the inner wall 5 of the air catching tube move upward due to the buoyancy, and can be driven from the outer wall 11 of the porous air guiding tube. When the large bubbles in the inner wall 5 of the air catching tube accumulate to a certain extent, they touch the outer wall 11 of the porous air guiding tube, and are introduced into the porous air guiding tube 6 through the through holes on the wall of the porous air guiding tube 6, and the bubble-free liquid flows out from the second pipe opening 8, thereby realizing the gas-liquid separation of the gas-liquid mixture.

[0024] The third aspect of the present invention provides a water electrolysis hydrogen production device comprising the connecting pipe described in the first aspect of the present invention, through which the connecting pipe described in the first aspect of the present invention is used to remove gas from the electrolyte using the method described in the second aspect of the present invention.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The connecting pipes designed in the present invention by means of different pipe inner sleeves can increase the interaction area between tiny bubbles and the gas-friendly pipe lining during electrolyte exchange, thereby improving the probability of tiny bubble retention. In the case of a large amount of bubble accumulation, rapid bubble transport can be achieved through the porous air guide pipe to prevent the entire bubble from clogging the pipe. Parallel vertically arranged pipes can also achieve rapid solution transport. With extremely small pipe sizes, the phenomenon of hydrogen and oxygen crossover caused by the connecting pipes between alkali solution storage tanks when exchanging electrolytes in the water electrolysis equipment can be greatly reduced, thereby improving the purity of hydrogen and oxygen produced by the water electrolysis equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

[0028] Figure 1 It is a schematic diagram of the connecting pipe structure of the present invention.

[0029] Figure 2 It is a top view of the connecting pipe of the present invention.

[0030] Figure 3 It is a cross-sectional view of the connecting pipe of the present invention.

[0031] Figure 4 Actual photos of the air guide tube material absorbing bubbles.

[0032] The names of the figure marks in the figure description are as follows: 1. main pipeline; 2. inner wall of main pipeline; 3. air capture pipe; 4. outer wall of air capture pipe; 5. inner wall of air capture pipe; 6. porous air guide pipe; 7. first pipeline opening; 8. second pipeline opening 2; 9. fixing part; 10. inner wall of porous air guide pipe; 11. outer wall of porous air guide pipe; 12. upper part of air capture pipe; 13. lower part of air capture pipe. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with embodiments.

[0034] Those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the art or the product specifications are used. If the manufacturer of the materials or equipment used is not specified, they are all conventional products that can be purchased.

[0035] Those skilled in the art will appreciate that, unless expressly stated otherwise, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" to another element, it may be directly connected to the other element, or there may be intermediate elements. In addition, the "connection" used herein may include wireless connections.

[0036] In the description of the present invention, unless otherwise specified, "plurality" means two or more than two. The terms "inside", "upper", "lower", etc., indicating positions or state relationships, are based on the positions or state relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operate in a specific position, and therefore cannot be understood as limiting the present invention.

[0037] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "provided with" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention will be understood according to specific circumstances.

[0038] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as those generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0039] The connecting pipe of the embodiment of the present invention comprises a main pipe 1, an air catching pipe 3, and a porous air guide pipe 6;

[0040] The main pipeline 1 includes a plurality of air-catching tubes 3 inside, each of which has an air-catching tube outer wall 4 and an air-catching tube inner wall 5. The air-catching tube outer walls 4 of adjacent air-catching tubes 3 are tightly fixed to each other, and the air-catching tube outer wall 4 of the air-catching tube 3 located on the outside is tightly fixed to the main pipeline inner wall 2 of the main pipeline 1;

[0041] Each of the air catching tubes 3 has a porous air guide tube 6 at its central axis. The porous air guide tube 6 has a porous air guide tube inner wall 10 and a porous air guide tube outer wall 11. The porous air guide tube 6 has a plurality of through holes on its wall that connect the porous air guide tube outer wall 11 with the porous air guide tube inner wall 10.

[0042] The porous air guide tube 6 is fixed to the central axis of the air capture tube 3 through a bilaterally symmetrical fixing member 9 .

[0043] The plurality of air-catching pipes 3 are arranged horizontally with the main pipe 1 , and the plurality of air-catching pipes 3 are gathered in parallel inside the main pipe 1 .

[0044] The main pipeline 1 includes a first pipeline opening 7 at one end and a second pipeline opening 8 at the other end;

[0045] The outer wall of the main pipe 1 is made of metal steel, the inner wall 2 of the main pipe is lined with polytetrafluoroethylene, a material resistant to alkali corrosion, and the inner wall 2 of the main pipe is roughened.

[0046] The air capture tube 3 is made of polytetrafluoroethylene, which is resistant to alkali corrosion, and the outer wall 4 and the inner wall 5 of the air capture tube are rough surfaces.

[0047] The connection between the plurality of air capture tubes 3 is adhesive connection;

[0048] The air capture pipe 3 and the main pipe 1 are connected by adhesive.

[0049] The porous air guide tube 6 is made of polytetrafluoroethylene, a corrosion-resistant and gas-friendly material.

[0050] The size of the porous air guide tube 6 is smaller than that of the air capture tube 3;

[0051] The through holes on the wall of the porous air guide tube 6 have uniform sizes and are arranged in an orderly manner.

[0052] The connecting pipe is used in a gas-liquid separation method, wherein the first pipe opening 7 is an inlet for a gas-liquid mixture, and the second pipe opening 8 is an outlet for a liquid;

[0053] The gas-liquid mixture enters from the first pipe opening 7, and the bubbles in the liquid are adhered to the inner wall 5 of the air catching tube, and are gradually accumulated from small bubbles into large bubbles. The large bubbles accumulated on the inner wall 5 of the air catching tube move upward due to the buoyancy, and can be driven from the outer wall 11 of the porous air guiding tube. When the large bubbles in the inner wall 5 of the air catching tube accumulate to a certain extent, they touch the outer wall 11 of the porous air guiding tube, and are introduced into the porous air guiding tube 6 through the through holes on the wall of the porous air guiding tube 6, and the bubble-free liquid flows out from the second pipe opening 8, thereby realizing the gas-liquid separation of the gas-liquid mixture.

[0054] The connecting pipe of this embodiment is used in a water electrolysis hydrogen production device to separate the gas in the electrolyte. The specific embodiment is as follows:

[0055] Example 1

[0056] Combined with Figure 1-3 The connecting pipe includes a main pipe 1, the first pipe port 7 of the main pipe is connected to the cathode liquid storage tank of the water electrolysis equipment, and the connection method includes but is not limited to direct pipe connection. The second pipe port 8 is connected to the anode liquid storage tank. Under working conditions, the cathode and anode liquid storage tanks begin to exchange solutions through the connecting pipe main pipe 1, and the electrolyte mixed bubbles in the cathode liquid storage tank enter from the first pipe port 7 and flow out from the second pipe port 8 to the anode liquid storage tank. There are a large number of air capture tubes 3 inside the main pipe 1. The material of the air capture tube 3 is an aerophilic material. The bubbles are adhered to the inner wall 5 of the air capture tube under the action of the aerophilic material, and gradually accumulate from small bubbles to large bubbles. The inner wall 5 of the air capture tube has a rough texture, which can increase the probability of collision with the bubbles and improve the efficiency of bubble removal. The bubbles are mainly accumulated in the upper part 12 of the air capture tube. Due to the upward action of buoyancy, the large bubbles accumulated on the inner wall will not continue to be washed downward even if there is a certain downward force of the electrolyte fluid, resulting in the situation that the bubbles are carried away by the fluid. There is a porous air guide tube 6 inside the air capture tube 3. The porous air guide tube is made of a super-air-friendly porous material, which can guide bubbles from the outer wall 11 of the porous air guide tube into the porous air guide tube 6 through the micro holes on the wall of the air guide tube. The inner wall 10 of the porous air guide tube is gas. When the large bubbles in the inner wall 5 of the air capture tube accumulate to a certain extent, they touch the outer wall 11 of the porous air guide tube, and the bubbles will be absorbed by the porous air guide tube. Figure 4 Thus, after the electrolyte at the cathode pipe port enters from the first pipe port 7 and a large number of bubbles are removed, the pure electrolyte without bubbles flows from the second pipe port 8 into the anode liquid storage tank.

[0057] The liquid in the connecting pipe flows periodically. After flowing from the cathode liquid storage tank through the connecting pipe main pipe 1 into the anode liquid storage tank, the electrolyte will flow back, flowing from the anode liquid storage tank through the connecting pipe main pipe 1 into the cathode liquid storage tank. The electrolyte enters from the second pipe port 8 and is discharged from the first pipe port 7. When the solution flows back, the bubbles staying on the upper part of the inner wall 5 of the air capture tube are brought back to the cathode liquid storage tank by the refluxed electrolyte, so that the bubbles flow back. At the same time, the electrolyte from the anode liquid storage tank will also carry a large number of bubbles, which are captured by the inner wall 5 of the air capture tube. When accumulated to a certain extent, they are absorbed by the porous air guide tube 6. The bubbles are mainly accumulated in the lower part 13 of the air capture tube, so that the bubbles in the refluxed electrolyte are trapped, and the pure gas-free electrolyte flows back to the cathode liquid storage tank.

[0058] Example 2

[0059] The positions of the liquid storage tanks in Example 1 can be interchanged, and the specific implementation method is as follows: Figure 1-3 The connecting pipe includes a main pipe 1, the first pipe port 7 of the main pipe is connected to the anode liquid storage tank of the electrolytic water device, and the connection method includes but is not limited to direct pipe connection. The second pipe port 8 is connected to the cathode liquid storage tank. Under working conditions, the cathode and anode liquid storage tanks begin to exchange solutions through the connecting pipe main pipe 1, and the electrolyte mixed bubbles in the anode liquid storage tank enter from the first pipe port 7 and flow out from the second pipe port 8 to the cathode liquid storage tank. There are a large number of air capture tubes 3 inside the main pipe 1. The material of the air capture tube 3 is an aerophilic material. The bubbles are adhered to the inner wall 5 of the air capture tube under the action of the aerophilic material, and gradually accumulate from small bubbles to large bubbles. The inner wall 5 of the air capture tube has a rough texture, which can increase the probability of collision with the bubbles and improve the efficiency of bubble removal. The bubbles are mainly accumulated in the upper part 12 of the air capture tube. Due to the upward action of buoyancy, the large bubbles accumulated on the inner wall will not continue to be washed downward even if there is a certain downward force of the electrolyte fluid, resulting in the situation that the bubbles are carried away by the fluid. There is a porous air guide tube 6 inside the air capture tube (3). The porous air guide tube is made of a super-air-friendly porous material, which can guide bubbles from the outer wall 11 of the porous air guide tube into the porous air guide tube 6 through the micro holes on the wall of the air guide tube. The inner wall 10 of the porous air guide tube is gas. When large bubbles in the inner wall 5 of the air capture tube accumulate to a certain extent, they touch the outer wall 11 of the porous air guide tube, and the bubbles will be absorbed by the porous air guide tube. Figure 4 Thus, after the electrolyte at the cathode pipe port enters from the first pipe port 7 and a large number of bubbles are removed, the pure electrolyte without bubbles flows into the cathode liquid storage tank from the second pipe port 8.

[0060] The liquid in the connecting pipe flows periodically. After flowing from the anode liquid storage tank through the connecting pipe main pipe 1 into the cathode liquid storage tank, the electrolyte will flow back, flowing from the cathode liquid storage tank through the connecting pipe main pipe 1 into the anode liquid storage tank. The electrolyte enters from the second pipe port 8 and is discharged from the first pipe port 7. When the solution flows back, the bubbles staying on the upper part of the inner wall 5 of the air capture tube are brought back to the anode liquid storage tank by the refluxed electrolyte, so that the bubbles flow back. At the same time, the electrolyte from the cathode liquid storage tank will also carry a large number of bubbles, which are captured by the inner wall 5 of the air capture tube. When accumulated to a certain extent, they are absorbed by the porous air guide tube 6. The bubbles are mainly accumulated in the lower part 13 of the air capture tube, so that the bubbles in the refluxed electrolyte are trapped, and the pure gas-free electrolyte flows back to the anode liquid storage tank.

Claims

1. A connecting pipe, characterized in that: It comprises a main pipeline (1), an air capture pipe (3), and a porous air guide pipe (6); The main pipeline (1) comprises a plurality of air-collecting tubes (3) inside, wherein the air-collecting tubes (3) have an air-collecting tube outer wall (4) and an air-collecting tube inner wall (5), the air-collecting tube outer walls (4) of adjacent air-collecting tubes (3) are in contact with each other, and the air-collecting tube outer walls (4) of the air-collecting tubes (3) located on the outside are in contact with the main pipeline inner wall (2) of the main pipeline (1); Each of the air capture tubes (3) has a porous air guide tube (6) at its central axis, the porous air guide tube (6) having a porous air guide tube inner wall (10) and a porous air guide tube outer wall (11), and the porous air guide tube (6) has a plurality of through holes on its wall that connect the porous air guide tube outer wall (11) with the porous air guide tube inner wall (10).

2. The connecting pipe according to claim 1, characterized in that: The porous air guide tube (6) is fixed to the central axis of the air capture tube (3) via a left-right symmetrical fixing piece (9).

3. The connecting pipe according to claim 1, characterized in that: The plurality of air-catching pipes (3) are arranged horizontally with the main pipe (1), and the plurality of air-catching pipes (3) are gathered in parallel inside the main pipe (1).

4. The connecting pipe according to claim 1, characterized in that: The main pipeline (1) comprises a first pipeline opening (7) located at one end and a second pipeline opening (8) located at the other end; The outer wall of the main pipeline (1) is made of metal, the inner wall (2) of the main pipeline is made of a material resistant to alkali corrosion, and the inner wall (2) of the main pipeline is roughened.

5. The connecting pipe according to claim 1, characterized in that: The air capture tube (3) is made of a material resistant to alkali corrosion, and the outer wall (4) and the inner wall (5) of the air capture tube are rough surfaces.

6. The connecting pipe according to claim 1, characterized in that: The connection method between the plurality of air capture pipes (3) includes adhesive connection and rope connection; The connection method between the air capture pipe (3) and the main pipeline (1) includes adhesive connection and rope connection.

7. The connecting pipe according to claim 1, characterized in that: The porous air guide tube (6) is made of a corrosion-resistant, gas-friendly material, which may be coated or made of an integrated material, including polytetrafluoroethylene.

8. The connecting pipe according to claim 1, characterized in that: The size of the porous air guide tube (6) is smaller than that of the air capture tube (3); The through holes on the wall of the porous air guide tube (6) have various size distribution modes, including random size and uniform size; and the through holes have various arrangement modes, including ordered arrangement and disordered arrangement.

9. A method for gas-liquid separation using the connecting pipe according to any one of claims 1 to 8, characterized in that: The first pipe opening (7) is an inlet for the gas-liquid mixture, and the second pipe opening (8) is an outlet for the liquid; The gas-liquid mixture enters from the first pipe opening (7), and the bubbles in the liquid are adhered to the inner wall (5) of the gas catching pipe, and gradually accumulate from small bubbles to large bubbles. The large bubbles accumulated on the inner wall (5) of the gas catching pipe move upward due to the buoyancy, and can be pushed from the outer wall (11) of the porous gas guiding pipe. When the large bubbles in the inner wall (5) of the gas catching pipe accumulate to a certain extent, they touch the outer wall (11) of the porous gas guiding pipe, and are introduced into the porous gas guiding pipe (6) through the through holes on the wall of the porous gas guiding pipe (6), and the bubble-free liquid flows out from the second pipe opening (8), thereby achieving gas-liquid separation of the gas-liquid mixture.

10. A water electrolysis hydrogen production device comprising the connecting pipe according to any one of claims 1 to 8, characterized in that: The gas in the electrolyte is removed by using the connecting pipe described in any one of claims 1 to 8 and the method described in claim 9.

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