Cathode structure with uniform gas-liquid pressure difference and chlor-alkali electrolytic tank comprising same

Abstract

The invention provides a cathode structure with uniform gas-liquid pressure difference and a chlor-alkali electrolytic tank comprising the cathode structure. The cathode structure comprises a gas chamber, a diffusion electrode and a catholyte chamber which are sequentially stacked, one side, facing the diffusion electrode, of the gas chamber is provided with a gas inlet branch channel close to the gas inlet, a gas outlet confluence channel close to the gas outlet, and a plurality of branch gas channels are arranged between the gas inlet branch channel and the gas outlet confluence channel; one side, facing the diffusion electrode, of the catholyte chamber is provided with a liquid inlet sub-channel close to the liquid inlet, a liquid outlet converging channel close to the liquid outlet, and a plurality of sub-liquid channels are arranged between the liquid inlet sub-channel and the liquid outlet converging channel. The cathode structure disclosed by the invention not only can realize uniform shunting, but also can remarkably reduce the pressure difference between the gas chamber and the cathode liquid chamber, is beneficial to process adjustment and exploration of optimal process conditions, is simple in structure and low in processing cost, has a self-adjustment function when the process fluctuates, and can recover to normal process conditions without starting and stopping.

Description

Technical Field

[0001] The invention belongs to the technical field of cathode structure design, and relates to a cathode structure with uniform gas-pressure differential and a chlor-alkali electrolytic cell comprising the cathode structure. Background Art

[0002] Chlorine and caustic soda produced in the chlor-alkali industry are one of the main raw materials for many important chemical products and are widely used in metallurgy, chemical industry, pesticide and other industries. The traditional chlor-alkali process produces chlorine at the anode and hydrogen at the cathode.

[0003] In recent years, in order to reduce the cell voltage, oxygen reduction reaction is used at the cathode to replace hydrogen evolution reaction, and gas diffusion electrode is used to overcome the defect of low solubility of oxygen in aqueous solution to increase current density. Therefore, the cathode structure includes a gas chamber, a gas diffusion electrode and a cathode liquid chamber. The gas diffusion electrode (GDE) is a special porous membrane electrode that can form a three-phase (gas, liquid, solid) membrane electrode, including a catalyst layer, a current collecting layer and a gas diffusion layer. Among them, the gas diffusion layer is connected to the gas chamber, composed of a gas-permeable and hydrophobic material, and is used for gas diffusion; the current collecting layer is between the gas diffusion layer and the catalyst layer, and is composed of a metal material, which is used to collect electrons, conduct current, and act as a supporting structure; the catalyst layer is connected to the cathode liquid chamber, and is composed of a hydrophilic material, which is the place where the catalytic reaction takes place.

[0004] Importantly, the key process parameter for the smooth operation of the oxygen reduction reaction at the cathode is the pressure difference between the gas and the cathode liquid. If the pressure difference between the gas and the cathode liquid is too low, the oxygen mass transfer is poor, and the current density is difficult to increase due to the influence of mass transfer. In addition, too low a pressure will cause the cathode liquid to seep into the gas chamber through the gas diffusion electrode, causing shutdown. If the pressure difference between the gas and the cathode liquid is too high, a large amount of gas will enter the cathode liquid chamber to form bubbles. Since the gas is a poor conductor with low conductivity, the increase in the gas content of the cathode chamber will cause the entire cathode voltage to be high, the energy consumption to be high, and the production cost to increase. The ideal cathode device has a uniform pressure difference between the gas and the cathode liquid throughout the cathode structure.

[0005] However, under the current process conditions, the superficial flow rates of gas and liquid are very low. If the traditional empty parallel flow channel is used, the friction resistance of the gas-liquid fluid can be ignored. The pressure difference between the gas chamber and the cathode liquid chamber is mainly caused by the static pressure difference, and the density of the gas is much smaller than that of the cathode liquid (generally 1:1000). Therefore, the pressure in the gas chamber can be maintained constant, while the pressure in the cathode liquid chamber changes greatly with the liquid level. This causes the pressure difference between the gas and the cathode liquid to change continuously in the vertical height, which brings great difficulties to process control. The main methods to solve this problem are air bag compensation structure and falling film structure. The air bag compensation structure is complex. In order to prevent the cathode liquid from entering the air bag, a very small gap with high hydrophobicity is required, which is difficult to process and costly. The falling film structure requires the addition of multiple components such as elastic elements and percolators, and once the process fluctuates, the gas enters the cathode chamber and it is difficult to discharge automatically, making it difficult to reduce the voltage and it must be restarted and stopped.

[0006] In order to solve the above problems, the present invention proposes a cathode structure for a chlor-alkali electrolytic cell with uniform gas-hydraulic pressure difference. Summary of the invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a cathode structure with uniform gas-liquid pressure difference and a chlor-alkali electrolytic cell including the same. In the present invention, through the specific setting of the cathode structure, not only can the diversion be uniform, but also the pressure difference between the gas chamber and the cathode liquid chamber can be significantly reduced, which is conducive to adjusting the process and exploring the optimal process conditions. It has a simple structure and low processing cost. It has a self-adjustment function when the process fluctuates, and can restore to normal process conditions without starting or stopping.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In the first aspect, the present invention provides a cathode structure with uniform gas-liquid pressure difference, the cathode structure comprising a gas chamber, a diffusion electrode and a cathode liquid chamber which are stacked in sequence; an air inlet is arranged at the bottom of the gas chamber, an air outlet is arranged at the top, and the side faces the diffusion electrode, an air inlet branch channel is arranged near the air inlet of the gas chamber, an air outlet converging channel is arranged near the air outlet, and a plurality of air branch channels are arranged between the air inlet branch channel and the air outlet converging channel; a liquid inlet is arranged at the bottom of the cathode liquid chamber, a liquid outlet is arranged at the top, and the side faces the diffusion electrode, an air inlet branch channel is arranged near the liquid inlet of the gas chamber, a liquid outlet converging channel is arranged near the liquid outlet, and a plurality of liquid branch channels are arranged between the liquid inlet branch channel and the liquid outlet converging channel.

[0010] In the present invention, through the specific setting of the cathode structure, not only can the flow be evenly distributed, but also the pressure difference between the gas chamber and the cathode liquid chamber can be significantly reduced, which is conducive to adjusting the process and exploring the optimal process conditions. It has a simple structure and low processing cost. It has a self-adjusting function when the process fluctuates, and can return to normal process conditions without starting or stopping.

[0011] It should be noted that the specific number of "several" in the present invention is not particularly limited, and those skilled in the art can make adaptive adjustments according to actual conditions.

[0012] As a preferred technical solution of the present invention, the air intake branch channel is arranged perpendicular to the air intake direction.

[0013] Preferably, the air outlet confluence channel is arranged perpendicular to the air inlet direction.

[0014] As a preferred technical solution of the present invention, the air branch passage is arranged parallel to the air intake direction.

[0015] It should be noted that the relative positions of the gas inlet shunt channel, gas outlet confluence channel, liquid inlet shunt channel, liquid outlet confluence channel, gas inlet, gas outlet, liquid inlet and liquid outlet are defined in the present invention, that is, the gas and cathode liquid are both in a vertical state of bottom-in and top-out, which can not only ensure that the direction of pressure difference reduction in the gas chamber is consistent with the direction of liquid static pressure difference reduction, so that the pressure difference between the gas chamber and the cathode liquid chamber is constant. Moreover, once the process fluctuates, the gas enters the liquid chamber through the gas diffusion electrode, and the upward flowing liquid can quickly sweep the bubbles out of the liquid chamber, reducing the gas content, thereby reducing the voltage difference of the cathode.

[0016] As a preferred technical solution of the present invention, a throttling hole is provided on each of the gas branch channels along the direction of the gas.

[0017] As a preferred technical solution of the present invention, the throttling channel is a gradually contracting and expanding structure.

[0018] It should be noted that the throttling channel in the present invention adopts a gradually contracting and expanding structure, which can not only enhance the friction resistance by expanding and contracting the flow channel, so that the pressure difference between the gas chamber and the cathode liquid chamber is constant in the vertical height, but also avoid the sudden expansion and contraction of the gas flow channel to form a reflux structure, which makes the gas mass transfer coefficient unevenly distributed in the vertical direction, thereby causing uneven current distribution, affecting the service life of the gas diffusion electrode, and other problems.

[0019] As a preferred technical solution of the present invention, the number of throttling holes is 50h-1; wherein h is the length of the air channel, in mm.

[0020] It should be noted that the number of throttling channels in the present invention is 50h-1, which represents 50*h minus 1. This number limitation can not only ensure that the pressure difference fluctuation between the gas and liquid sides does not exceed 200pa, close to constant pressure, but also avoid the problem of processing difficulties and increased costs caused by overly complex structures.

[0021] It should be noted that the present invention does not impose any special limitation on the specific length h of the gas channel, which can be set with reference to the size of the overall cathode structure, and those skilled in the art can make adaptive adjustments according to actual conditions.

[0022] As a preferred technical solution of the present invention, the distance between adjacent throttling channels is 20 to 30 mm, for example, it can be 20 mm, 22 mm, 24 mm, 26 mm, 28 mm, 30 mm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] In the present invention, the distance between adjacent throttling channels is 20-30 mm, which can ensure that the pressure difference fluctuation between the gas and liquid sides does not exceed 200 Pa.

[0024] As a preferred technical solution of the present invention, the side of the liquid distribution channel facing the liquid inlet is a diversion hole.

[0025] Preferably, the diversion hole is a gradually contracting and expanding structure.

[0026] As a preferred technical solution of the present invention, the ratio of the sum of the areas at the minimum cross-sectional area of ​​the diversion holes to the cross-sectional area of ​​the liquid inlet diversion channel is (0.25-0.35):1, for example, it can be 0.25:1, 0.27:1, 0.29:1, 0.3:1, 0.32:1, 0.34:1, 0.35:1, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] It should be noted that the specific structure and cross-sectional area setting of the diversion holes are limited in the present invention, which can make the friction resistance of the liquid passing through the diversion holes much greater than the friction resistance of the liquid passing through the liquid inlet diversion channel, so that the liquid is evenly distributed in each parallel diversion channel, and the gradually shrinking and expanding structure can avoid the sudden expansion and contraction of the liquid flow channel to form a reflux structure, resulting in uneven mass transfer on the cathode liquid side, uneven current distribution, affecting the service life of the gas diffusion electrode and other problems.

[0028] In a second aspect, the present invention provides a chlor-alkali electrolytic cell, comprising the cathode structure described in the first aspect.

[0029] It should be noted that the chlor-alkali electrolytic cell in the present invention can be any form of electrolytic cell structure, and its structure can include the cathode structure in the present invention. The specific connection method and existence method of the cathode structure can be adaptively adjusted by those skilled in the art according to actual conditions.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The oxygen reduction reaction is used at the cathode to replace the traditional hydrogen evolution reaction in the chlor-alkali electrolytic cell. Since the oxygen reduction potential is higher than that of the hydrogen evolution reaction, the cell voltage can be greatly reduced at the same current density, which can reduce energy consumption and production costs.

[0032] (2) Simple structure and low processing difficulty. Compared with the existing air bag compensation structure and falling film structure, the current structure only adds a throttle hole in the gas parallel flow channel, relying on the expansion and contraction of the flow channel to enhance the friction resistance of the gas, so that the friction resistance on the gas side is equal to the static pressure difference on the liquid side, so that the pressure difference between the gas and the liquid is close to constant in the entire cathode structure, which is conducive to experimental exploration of the optimal process conditions. The constant pressure difference can not only avoid the flooding problem caused by the bottom gas pressure being too low compared to the cathode liquid, but also avoid the top gas pressure being too high compared to the cathode liquid, causing oxygen to enter the cathode liquid chamber to form bubbles, making the process stable and safe. This structure not only realizes the process of constant pressure difference between the gas side and the cathode liquid side, but also does not have strict hydrophobic material and processing accuracy requirements like the air bag compensation structure, nor does it add multiple components such as elastic elements and percolators like the falling film structure, thus greatly reducing the complexity and cost of the equipment.

[0033] (3) Uniform diversion effect. The throttling holes set in the gas chamber can make the friction resistance of the gas passing through the gas parallel channels much greater than the friction resistance of the gas passing through the gas diversion main pipeline, so it can act as a gas distributor, so that the gas flow channels in each parallel branch pipe are evenly distributed. At the same time, diversion holes are also set in the cathode liquid chamber, so that the friction resistance of the liquid passing through the diversion holes is much greater than the friction resistance of the liquid passing through the liquid inlet diversion channel, so that the liquid is evenly distributed in each parallel diversion channel, ensuring uniform current distribution in the horizontal direction and enhancing the service life of the electrode.

[0034] (4) It has an automatic adjustment function when the process fluctuates. When the process fluctuates, for example, the pressure on the gas side is suddenly much greater than the pressure on the liquid side, and oxygen enters the cathode liquid chamber and bubbles, the bubbles formed can be taken away in time by the cathode liquid flowing from bottom to top, and will not cause bubbles to accumulate in the cathode chamber like the falling film structure, thereby causing the voltage to continue to increase. The machine must be stopped and the bubbles must be manually removed to restore the normal potential.

[0035] (5) Uniform gas-liquid mass transfer. Both the gas chamber and the cathode liquid chamber use a gradually shrinking and expanding hole structure to avoid the sudden expansion and contraction of the flow channel to form a reflux structure, which makes the mass transfer level in the vertical direction uneven, resulting in uneven current distribution, affecting the service life of the gas diffusion electrode and other problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 An overall schematic diagram of a cathode structure provided in a specific embodiment of the present invention;

[0037] Figure 2 A schematic diagram of the structure of a gas chamber in a cathode structure provided in a specific embodiment of the present invention;

[0038] Figure 3 A schematic diagram of the structure of a cathode liquid chamber in a cathode structure provided in a specific embodiment of the present invention;

[0039] Among them, 1-gas chamber; 2-diffusion electrode; 3-cathode liquid chamber; 4-air inlet; 5-liquid inlet; 6-air outlet; 7-liquid outlet; 8-air inlet diverter channel; 9-air diverter channel; 10-throttling hole channel; 11-air outlet confluence channel; 12-liquid inlet diverter channel; 13-diverter hole; 14-liquid diverter channel; 15-liquid outlet confluence channel. DETAILED DESCRIPTION

[0040] It should be understood that, in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0041] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0042] Those skilled in the art should understand that the present invention necessarily includes necessary pipelines, conventional valves and general pump equipment for realizing a complete process, but the above content does not belong to the main inventive point of the present invention. Those skilled in the art can add layouts on their own based on the process flow and equipment structure selection, and the present invention does not make special requirements and specific limitations on this.

[0043] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0044] In one embodiment, the present invention provides a cathode structure with a uniform gas-pressure differential, such as Figure 1 , Figure 2 and Figure 3 As shown, the cathode structure includes a gas chamber 1, a diffusion electrode 2 and a cathode liquid chamber 3 which are stacked in sequence; an air inlet 4 is provided at the bottom of the gas chamber 1, and an air outlet 6 is provided at the top, and the side faces the diffusion electrode 2; an air inlet branch channel 8 is provided near the air inlet 4 of the gas chamber 1, and an air outlet confluence channel 11 is provided near the air outlet 6, and a plurality of air branch channels 9 are provided between the air inlet branch channel 8 and the air outlet confluence channel 11; a liquid inlet 5 is provided at the bottom of the cathode liquid chamber 3, and a liquid outlet 7 is provided at the top, and the side faces the diffusion electrode 2; a liquid inlet branch channel 12 is provided near the liquid inlet 5 of the cathode liquid chamber 3, and a liquid outlet confluence channel 15 is provided near the liquid outlet 7, and a plurality of liquid branch channels 14 are provided between the liquid inlet branch channel 12 and the liquid outlet confluence channel 15.

[0045] In the present invention, through the specific setting of the cathode structure, not only can the flow be evenly distributed, but also the pressure difference between the gas chamber 1 and the cathode liquid chamber 3 can be significantly reduced, which is conducive to adjusting the process and exploring the optimal process conditions. It has a simple structure and low processing cost. It has a self-adjusting function when the process fluctuates, and can restore to normal process conditions without starting or stopping.

[0046] Furthermore, the air inlet branch channel 8 is arranged perpendicular to the air inlet direction, and the air outlet converging channel 11 is arranged perpendicular to the air inlet direction.

[0047] Furthermore, the air branch passage 9 is arranged parallel to the air intake direction.

[0048] It should be noted that the relative positions of the gas inlet flow channel 8, the gas outlet confluence channel 11, the liquid inlet flow channel 12, the liquid outlet confluence channel 15, the gas inlet 4, the gas outlet 6, the liquid inlet 5 and the liquid outlet 7 are defined in the present invention, that is, the gas and the cathode liquid are both in a vertical state of entering from the bottom and exiting from the top, which can not only ensure that the direction of the pressure difference reduction in the gas chamber 1 is consistent with the direction of the liquid static pressure difference reduction, so that the pressure difference between the gas chamber 1 and the cathode liquid chamber 3 is constant. Moreover, once the process fluctuates, the gas enters the liquid chamber through the gas diffusion electrode 2, and the upward flowing liquid can quickly sweep the bubbles out of the liquid chamber, reduce the gas content, and thus reduce the voltage difference of the cathode.

[0049] Furthermore, along the direction of the gas, a throttling hole 10 is provided on each gas branch channel 9 .

[0050] Furthermore, the throttling channel 10 is a gradually contracting and expanding structure.

[0051] It should be noted that the throttling channel 10 in the present invention adopts a gradually contracting and expanding structure, which can not only enhance the friction resistance by expanding and contracting the flow channel, so that the pressure difference between the gas chamber 1 and the cathode liquid chamber 3 is constant in the vertical height, but also avoid the sudden expansion and contraction of the gas flow channel to form a reflux structure, which makes the gas mass transfer coefficient unevenly distributed in the vertical direction, thereby causing uneven current distribution, affecting the service life of the gas diffusion electrode 2 and other problems.

[0052] Furthermore, the number of throttling holes 10 is 50h-1, wherein h is the length of the air distribution channel 9, in mm.

[0053] It should be noted that the throttling channel 10 in the present invention is provided with 50h-1, which can not only ensure that the pressure difference fluctuation between the gas and liquid sides does not exceed 200pa, close to constant pressure, but also avoid the problem of processing difficulties and increased costs caused by overly complex structures.

[0054] Furthermore, the distance between adjacent throttling channels 10 is 20 to 30 mm, for example, it can be 20 mm, 22 mm, 24 mm, 26 mm, 28 mm, 30 mm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0055] Furthermore, a side of the liquid dividing channel 14 facing the liquid inlet 5 is a flow dividing hole 13 .

[0056] Furthermore, the diverter hole 13 is a gradually contracting and expanding structure.

[0057] Furthermore, the ratio of the sum of the areas at the minimum cross-sectional area of ​​the diversion hole 13 to the cross-sectional area of ​​the liquid inlet diversion channel 12 is (0.25-0.35):1, for example, it can be 0.25:1, 0.27:1, 0.29:1, 0.3:1, 0.32:1, 0.34:1, 0.35:1, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0058] It should be noted that the specific structure and cross-sectional area setting of the diverter hole 13 are limited in the present invention, which can make the friction resistance of the liquid passing through the diverter hole 13 much greater than the friction resistance of the liquid passing through the liquid inlet diverter channel 12, so that the liquid is evenly distributed in each parallel diverter channel 14, and the gradually shrinking and expanding structure can avoid the sudden expansion and contraction of the liquid flow channel to form a reflux structure, resulting in uneven mass transfer on the cathode liquid side, uneven current distribution, affecting the service life of the gas diffusion electrode 2, and other problems.

[0059] In another specific embodiment, the present invention provides a chlor-alkali electrolytic cell, which includes the cathode structure described above.

[0060] It should be noted that the chlor-alkali electrolytic cell in the present invention can be any form of electrolytic cell structure, and its structure can include the cathode structure in the present invention. The specific connection method and existence method of the cathode structure can be adaptively adjusted by those skilled in the art according to actual conditions.

[0061] Example 1

[0062] This embodiment provides a cathode structure with a uniform gas-pressure differential, wherein:

[0063] The cathode structure includes a gas chamber 1, a diffusion electrode 2 and a cathode liquid chamber 3 which are stacked in sequence; an air inlet 4 is arranged at the bottom of the gas chamber 1, and an air outlet 6 is arranged at the top, and faces the side of the diffusion electrode 2; an air inlet branch channel 8 is arranged near the air inlet 4 of the gas chamber 1, and an air outlet confluence channel 11 is arranged near the air outlet 6, and a plurality of air branch channels 9 are arranged between the air inlet branch channel 8 and the air outlet confluence channel 11; a liquid inlet 5 is arranged at the bottom of the cathode liquid chamber 3, and a liquid outlet 7 is arranged at the top, and faces the side of the diffusion electrode 2; a liquid inlet branch channel 12 is arranged near the liquid inlet 5 of the cathode liquid chamber 3, and a liquid outlet confluence channel 15 is arranged near the liquid outlet 7, and a plurality of liquid branch channels 14 are arranged between the liquid inlet branch channel 12 and the liquid outlet confluence channel 15.

[0064] The air inlet branch channel 8 is arranged perpendicular to the air inlet direction, the air outlet converging channel 11 is arranged perpendicular to the air inlet direction, and the air branch channel 9 is arranged parallel to the air inlet direction.

[0065] Along the direction of the gas, each gas channel 9 is provided with a throttling hole 10, and the throttling hole 10 is a gradually contracting and expanding structure, and there are 50h-1 throttling holes 10; wherein, h is the length of the gas channel 9, which is 500mm; and the distance between adjacent throttling holes 10 is 20mm.

[0066] The side of the liquid diversion channel 14 facing the liquid inlet 5 is a diversion hole 13, which is a gradually contracting and expanding structure. The ratio of the total area of ​​the diversion hole 13 at the minimum cross-sectional area to the cross-sectional area of ​​the liquid inlet diversion channel 12 is 0.3:1.

[0067] Example 2

[0068] This embodiment provides a cathode structure, which is different from Embodiment 1 in that the ratio of the total area of ​​the minimum cross-sectional area of ​​the diverter hole 13 to the cross-sectional area of ​​the liquid inlet diverter channel 12 is 0.23:1, and other parameters and conditions are the same as those in Embodiment 1.

[0069] Example 3

[0070] This embodiment provides a cathode structure, which is different from Embodiment 1 in that the ratio of the total area of ​​the minimum cross-sectional area of ​​the diverter hole 13 to the cross-sectional area of ​​the liquid inlet diverter channel 12 is 0.36:1, and other parameters and conditions are the same as those in Embodiment 1.

[0071] Comparative Example 1

[0072] This comparative example provides a cathode structure, which is different from Example 1 in that the flow channel structure of the gas outlet chamber is the same as the flow channel structure of the cathode liquid chamber 3, and other parameters and conditions are the same as those of Example 1.

[0073] By testing the flow distribution and pressure drop of the cathode structures in the above embodiments and comparative examples, it is found that:

[0074] Compared with the cathode structures in Examples 2 and 3, the cathode structure of Example 1 has a lower pressure drop while ensuring uniform flow. This is because the ratio of the sum of the areas at the minimum cross-sectional area of ​​the diverter hole 13 to the cross-sectional area of ​​the liquid inlet diverter channel 12 is limited to 0.25 to 0.35:1, so that the pressure drop generated by the diverter hole is just large enough to ensure uniform flow distribution without causing energy waste.

[0075] Compared with the cathode structure in comparative example 1, the cathode structure of embodiment 1 has better performance of uniform gas-liquid pressure difference. This is because the present application distinguishes the specific structures of the gas chamber 1 and the cathode liquid chamber 3, so that there is a strong friction resistance in the gas channel 9 in the gas chamber 1, while the friction resistance of the liquid channel 14 in the cathode liquid chamber 3 is negligible, and the pressure difference change only comes from the static pressure difference of the liquid. The cathode structure in the present invention makes the friction resistance on the gas side equal to the static pressure difference on the liquid side, thereby ensuring that the pressure difference between the gas and the liquid is close to constant over the entire cathode structure.

[0076] In summary, the present invention can not only achieve uniform flow diversion through the specific setting of the cathode structure, but also significantly reduce the pressure difference between the gas chamber 1 and the cathode liquid chamber 3, which is beneficial to adjust the process and explore the optimal process conditions. It has a simple structure and low processing cost. It has a self-adjusting function when the process fluctuates, and can restore to normal process conditions without starting or stopping.

[0077] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A cathode structure with uniform gas-pressure differential, characterized in that: The cathode structure comprises a gas chamber, a diffusion electrode and a cathode liquid chamber which are stacked in sequence; The gas chamber is provided with an air inlet at the bottom and an air outlet at the top, and the air inlet is directed toward one side of the diffusion electrode. The gas chamber is provided with an air inlet branch channel near the air inlet, and an air outlet converging channel near the air outlet. A plurality of air branch channels are provided between the air inlet branch channel and the air outlet converging channel. The cathode liquid chamber is provided with a liquid inlet at the bottom and a liquid outlet at the top, and faces one side of the diffusion electrode. The cathode liquid chamber is provided with a liquid inlet branch channel near the liquid inlet, and a liquid outlet confluence channel near the liquid outlet. A plurality of liquid branch channels are provided between the liquid inlet branch channel and the liquid outlet confluence channel.

2. The cathode structure according to claim 1, characterized in that: The air intake branch channel is arranged perpendicular to the air intake direction; Preferably, the air outlet confluence channel is arranged perpendicular to the air inlet direction.

3. The cathode structure according to claim 1 or 2, characterized in that: The air branch passage is arranged parallel to the air intake direction.

4. The cathode structure according to claim 1, characterized in that: Along the direction of the gas, each of the gas distribution channels is provided with a throttling hole.

5. The cathode structure according to claim 4, characterized in that: The throttling channel is a gradually contracting and expanding structure.

6. The cathode structure according to claim 4 or 5, characterized in that: The throttling channel is provided with 50h-1; Wherein, h is the length of the air channel, in mm.

7. The cathode structure according to any one of claims 4 to 6, characterized in that: The distance between adjacent throttling channels is 20 to 30 mm.

8. The cathode structure according to any one of claims 1 to 7, characterized in that: The side of the liquid distribution channel facing the liquid inlet is a diversion hole; Preferably, the diversion hole is a gradually contracting and expanding structure.

9. The cathode structure according to claim 8, characterized in that: The ratio of the total area of ​​the diversion hole at the minimum cross-sectional area to the cross-sectional area of ​​the liquid inlet diversion channel is (0.25-0.35):

1.

10. A chlor-alkali electrolytic cell, characterized in that: The chlor-alkali electrolytic cell comprises the cathode structure according to any one of claims 1-9.

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