Tubular electrolytic cell for enhancing bubble coalescence and separation, electrolysis device and electrolysis method

Abstract

The invention discloses a tubular electrolytic cell for strengthening bubble coalescence and separation, an electrolysis device and an electrolysis method. The tubular electrolytic cell comprises a shell and a plurality of electrode tubes arranged in the shell; the electrode tube comprises a tubular diaphragm, an in-tube electrode and an out-tube electrode, the in-tube electrode and the out-tube electrode are arranged on the inner surface and the outer surface of the tubular diaphragm respectively, a tube pass channel is formed in the in-tube electrode, and a shell pass channel is formed between the outside of the out-tube electrode and the inner wall of the shell; a bubble coalescence flow guide structure is also arranged in the tube pass channel and is used for inducing micro bubbles generated by electrolysis to grow and export; the bubble coalescence flow guide structure comprises a supporting column and weaving inner pieces fixed to the upper portion and the lower portion of the supporting column. The woven inner part is formed by weaving hydrophilic silk threads and hydrophobic silk threads, and a flow channel is macroscopically formed. According to the invention, the woven inner part is arranged in the tube pass channel, so that coalescence and rapid separation of bubbles are promoted, bubble foaming is effectively prevented, and the gas content of the electrolytic cell is reduced.

Description

Technical Field

[0001] This invention belongs to the field of water electrolysis for hydrogen production technology, specifically relating to a tubular electrolyzer, electrolysis device, and electrolysis method for enhancing bubble coalescence and separation. Background Technology

[0002] Hydrogen energy, as a zero-carbon energy carrier, not only has very high energy density, but also enables large-scale, long-term energy storage, making it an important carrier for the green and low-carbon transformation of energy.

[0003] Among all current methods of hydrogen production via water electrolysis, alkaline water electrolysis is the most widely used in industrial hydrogen production due to its low equipment cost and mature process. However, its further development is currently constrained by excessively high energy consumption. This is mainly because a large number of small bubbles are generated during the water electrolysis process, especially at high current densities. These small bubbles cause ohmic resistance drops, affecting the conductivity within the electrolyzer and the effective reaction area on the electrode surface, thus increasing energy consumption and operational risks. Therefore, researching how to reduce the impact of bubbles on electrolysis efficiency is of great significance. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in the prior art by proposing a tubular electrolytic cell, electrolysis device, and electrolysis method for enhancing bubble coalescence and separation.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A first aspect of the present invention is to provide a tubular electrolytic cell for enhancing bubble coalescence and separation, the tubular electrolytic cell comprising a housing and a plurality of electrode tubes disposed within the housing, and a tube sheet for fixing the electrode tubes;

[0007] The electrode tube includes a tubular diaphragm, and an inner electrode and an outer electrode respectively disposed on the inner and outer surfaces of the tubular diaphragm. The inner electrode forms a tube-side channel, and the outer side of the outer electrode, the inner wall of the shell, and the tube sheet form a shell-side channel.

[0008] The tube passage is also equipped with a bubble coalescence guiding structure to induce the growth and outflow of microbubbles generated by electrolysis; the bubble coalescence guiding structure includes a support column and a braided inner component fixed to the upper and lower parts of the support column; the braided inner component is made of hydrophilic and hydrophobic yarns, wherein:

[0009] The hydrophilic and hydrophobic threads are spirally wound to form braided threads, which are braided in an M-shape to form a braided inner part with multiple flow channels on a macroscopic scale; the braided inner part is spirally wound on the support column.

[0010] In some embodiments, the angle α between the flow channel of the woven inner part and the horizontal plane is set to 20° < α < 65°.

[0011] In some embodiments, the volume ratio of the hydrophilic filaments to the hydrophobic filaments is 2:1 to 6:1, and the diameter of the hydrophilic or hydrophobic filaments is 80 μm to 200 μm.

[0012] The hydrophilic filament is made of one or more of the following materials: platinum, nickel, graphene, titanium, and stainless steel.

[0013] The hydrophobic filaments are made of one or more of polytetrafluoroethylene, polyvinylidene fluoride, polyolefins, and polyamides.

[0014] In some embodiments, the spacing between the hydrophilic or hydrophobic threads in the braided inner component is 0.1 mm to 1.0 mm; the braiding density is 50 to 200 mesh; the porosity of the braided inner component at the lower part of the support column is 83% to 87%; and the porosity of the braided inner component at the upper part is 90% to 95%.

[0015] In some embodiments, the bubble coalescence and flow guiding structure further includes a spiral flow channel disposed on the support column, the spiral flow channel being located between the upper and lower woven inner parts, and the spiral angle of the spiral flow channel being 20° to 65°;

[0016] The spiral flow channel has a width of 95 mm to 155 mm and a height of 650 mm to 850 mm; the spiral flow channel is made of one of nickel, stainless steel, and nickel-iron-chromium alloy.

[0017] In some embodiments, the tubular electrolytic cell has a cylindrical structure with a diameter of 1500 mm to 2500 mm and a height of 1600 mm to 1800 mm;

[0018] The electrode tube has an inner diameter of 100 mm to 160 mm, an outer diameter of 110 mm to 180 mm, a tube thickness of 10 mm to 40 mm, and a height of 1400 mm to 1600 mm.

[0019] In some embodiments, the diameter of the support column is 50 mm to 80 mm and the height is 1350 mm to 1550 mm; the material of the support column is selected from nickel, stainless steel and nickel-iron-chromium alloy.

[0020] The length of the woven inner part at the lower part of the support column is 200 mm to 250 mm, and the distance between it and the bottom of the support column is 200 mm to 300 mm.

[0021] The woven inner part of the upper part of the support column has a length of 200 mm to 250 mm and is installed close to the spiral flow channel.

[0022] A second aspect of the present invention is to provide an electrolysis method using the above-described tubular electrolytic cell, the electrolysis method comprising the following steps:

[0023] The electrolyte enters the tube-side channel from the bottom of the tubular electrolyzer and flows upward. After electrolysis, the electrolyte becomes a gas-liquid mixture containing a large number of microbubbles. As the microbubbles rise, they pass through the braided inner components. Due to the low wettability of the hydrophobic threads in the braided inner components, they provide aggregation sites for the microbubbles at the microscopic level, continuously inducing the microbubbles to coalesce and grow. Meanwhile, the spiral upward flow channel structure formed by the braided inner components at the macroscopic level induces larger bubbles to detach rapidly, reducing bubble accumulation and blockage.

[0024] The shell-side electrolyte enters from the bottom of the tubular electrolytic cell and flows upward in the shell-side channel, washing the outer surface of all electrode tubes. The bubbles generated by electrolysis are efficiently carried away by the flowing shell-side electrolyte.

[0025] In some embodiments, the flow rate of the electrolyte in the tubular electrolytic cell is 0.03 m / s to 0.07 m / s, and the current density is 250 A / m² to 800 A / m²; under normal pressure, the operating temperature of the tubular electrolytic cell is 55 ℃ to 85 ℃.

[0026] A third aspect of the present invention is to provide an electrolysis apparatus employing the above-described tubular electrolytic cell, the electrolysis apparatus comprising the above-described tubular electrolytic cell, and a first circulation unit and a second circulation unit arranged in parallel.

[0027] The first circulation unit includes a first gas-liquid separator, a first alkaline solution mixer and a first circulation pump connected in sequence. The inlet of the first gas-liquid separator and the outlet of the first circulation pump are respectively connected to the inlet and outlet of the tube side channel of the tubular electrolyzer to realize the circulation of the tube side electrolyte.

[0028] The second circulation unit includes a second gas-liquid separator, a second alkaline solution mixer, and a second circulation pump connected in sequence. The inlet of the second gas-liquid separator and the outlet of the second circulation pump are respectively connected to the inlet and outlet of the shell-side channel of the tubular electrolyzer to realize the circulation of the shell-side electrolyte.

[0029] The gas phase outlets of the first gas-liquid separator and the second gas-liquid separator are respectively connected to a gas processing device.

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

[0031] (1) The tubular electrolytic cell of the present invention forms a shell-and-tube heat exchanger structure by setting several electrode tubes inside the shell. In the shell-side channel, since the whole is interconnected and combined with the curved surface characteristics of the electrode tubes, the shell-side electrolyte washes the outer surface of all electrode tubes during the flow process, and the bubbles generated by electrolysis are efficiently carried away by the flowing shell-side electrolyte.

[0032] (2) The present invention provides a bubble coalescence guiding structure composed of support columns and braided inner components within the tube channel. The braided inner components are made of hydrophilic and hydrophobic composite yarns and form a macroscopic spiral upward flow channel. From a microscopic perspective, the inherent low surface wettability of the hydrophobic material continuously provides nucleation sites for microbubble coalescence on the wall surface, promoting the spontaneous coalescence and growth of microbubbles. At the macroscopic structural level, the spiral upward flow channel can guide larger bubbles to accelerate their escape, thereby effectively suppressing bubble aggregation and the resulting channel blockage. It can also improve the uniformity of fluid-wall contact and enhance the stability of electrolysis.

[0033] (3) The present invention further provides a spiral flow channel between the braided inner parts in the bubble coalescence and flow guiding structure to provide a spiral upward channel for the gas and liquid phases, so that the fluid flows uniformly in the tube channel, fully contacts the electrode inside the tube, strengthens the mass transfer and heat transfer process, and improves the electrolysis efficiency.

[0034] (4) The tubular electrolyzer of the present invention can effectively control the size of the bubbles in the tubular electrolyte to the millimeter level, prevent the bubbles from foaming, reduce the gas content, optimize the flow field distribution and fluid uniformity in the tubular electrolyzer, thereby improving the overall electrolysis efficiency and operational stability. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the tubular electrolytic cell of the present invention.

[0036] Figure 2 This is a top view of the electrode tube.

[0037] Figure 3 This is a schematic diagram of the structure of a single electrode tube with a built-in bubble coalescence and flow guiding structure.

[0038] Figure 4 This is a schematic diagram of the bubble coalescence and flow guiding structure.

[0039] Figure 5 a and Figure 5 In the diagram, b represents the top view and unfolded schematic diagram of the woven inner part, respectively.

[0040] Figure 6 This is a schematic diagram of the braided inner components being wound on the support column.

[0041] Figure 7This is a schematic diagram illustrating the principle of enhanced bubble coalescence and separation in the tubular electrolytic cell of the present invention.

[0042] Figure 8 This is a schematic diagram of the electrolysis device of the present invention.

[0043] Figure 9 This is a comparison chart of the gas holdup of Example 3 and Comparative Example 1 under different apparent liquid rates.

[0044] Figure 10 This is a comparison chart of energy consumption between Example 3 and Comparative Example 1 at different apparent liquid rates.

[0045] In the picture:

[0046] 10 - Tubular electrolytic cell; 20 - First gas-liquid separator; 30 - First alkali solution mixer; 40 - First circulating pump; 50 - Second gas-liquid separator; 60 - Second alkali solution mixer; 70 - Second circulating pump; 80 - Gas processing equipment;

[0047] 100 - Shell; 110 - Tube-side inlet; 120 - Shell-side inlet; 130 - Tube-side outlet; 140 - Shell-side outlet; 150 - Tube sheet;

[0048] 200 - Electrode tube; 210 - Tubular diaphragm; 220 - Inner electrode; 230 - Outer electrode;

[0049] 300 - Bubble coalescence and flow guiding structure; 310 - Support column; 320 - Braided inner part; 330 - Spiral flow channel. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are all within the scope of protection of this application.

[0051] Example 1: A tubular electrolyzer for enhanced bubble coalescence and separation

[0052] refer to Figure 1 The tubular electrolytic cell 10 for enhanced bubble coalescence and separation in this embodiment adopts a vertical structure, including a shell 100 and a plurality of electrode tubes 200 disposed in the shell, and a tube plate 150 for fixing the electrode tubes 200; the tube plate 150 is provided with a plurality of through holes (not shown in the figure) adapted to the electrode tubes 200, and the upper and lower ends of the electrode tubes 200 are fixed in the through holes.

[0053] Combination Figure 2As shown, the electrode tube 200 is hollow inside and includes a tubular diaphragm 210, and an inner electrode 220 and an outer electrode 230 respectively disposed on the inner and outer surfaces of the tubular diaphragm 210. The inner electrode 220 forms a tube-side channel, and the outer side of the outer electrode 230, the inner wall of the housing 100, and the tube sheet 150 form a shell-side channel.

[0054] The lower part of the housing 100 is provided with a tube-side inlet 110 and a shell-side inlet 120, and the upper part is provided with a tube-side outlet 130 and a shell-side outlet 140.

[0055] When one of the inner electrode 220 and the outer electrode 230 acts as the cathode, the other acts as the anode. During electrolysis, the electrolyte flows through both the tube-side and shell-side channels from bottom to top. Hydrogen evolution occurs in one channel, and oxygen evolution occurs in the other, avoiding direct contact between hydrogen and oxygen and significantly reducing the risk of hydrogen-oxygen cross-contamination. During electrolysis, numerous microbubbles form on the inner and outer surfaces of the electrode tube 200. Because the shell-side channel is entirely connected, and considering the curved surface of the electrode tube 200, the flowing electrolyte in the shell side washes over the outer surface of all electrode tubes 200, efficiently carrying away the bubbles generated during electrolysis. In contrast, the shell-side channel, which consists of several smaller internal spaces, is more prone to bubble blockage compared to the entirely connected tube-side channel.

[0056] Therefore, as Figure 3 and Figure 4 As shown, the present invention also provides a bubble coalescence and flow guiding structure 300 in the tube channel, which is used to induce the growth and discharge of micro bubbles in the gas-liquid mixture generated by electrolysis in the tube channel, while improving the flow field distribution of the fluid and making the flow field distribution uniform.

[0057] The bubble coalescence guiding structure 300 includes a support column 310 and a braided inner component 320 fixed to the upper and lower parts of the support column 310; the braided inner component 320 is woven from hydrophilic and hydrophobic yarns, wherein:

[0058] like Figure 5 and Figure 6 As shown, the hydrophilic and hydrophobic threads are spirally wound to form braided threads, which are braided in an M-shape to form a braided inner part 320 with multiple flow channels on a macroscopic scale; the braided inner part 320 is spirally wound on the support column 310.

[0059] Furthermore, the angle α between the flow channel of the woven inner part 320 and the horizontal plane is set to 20° < α < 65°;

[0060] Furthermore, in the braided inner component 320, the volume ratio of hydrophilic yarns to hydrophobic yarns is 2:1 to 6:1. The hydrophobic yarns facilitate the coalescence of microbubbles, forming larger bubbles, while an appropriate amount of hydrophilic yarns helps the large bubbles formed by coalescence to detach quickly along the flow channel. The diameter of the hydrophilic or hydrophobic yarns is 80 μm to 200 μm.

[0061] Furthermore, the hydrophilic filament is made of one or more of platinum, nickel, graphene, titanium, and stainless steel; the hydrophobic filament is made of one or more of polytetrafluoroethylene, polyvinylidene fluoride, polyolefin, and polyamide.

[0062] Furthermore, in the braided inner part 320, the spacing between the hydrophilic or hydrophobic threads is 0.1 mm to 1.0 mm; the braiding density is 50 to 200 mesh; the porosity of the braided inner part 320 at the lower part of the support column 310 is 83% to 87%, and the porosity of the braided inner part 320 at the upper part is 90% to 95%.

[0063] Preferably, return to Figure 4 The bubble coalescence and flow guiding structure 300 further includes a spiral flow channel 330 disposed on the support column 310. The spiral flow channel 330 is located between the upper and lower woven inner parts 320 and is used to guide the bubbles to rise. The spiral angle of the spiral flow channel 330 is 20° to 65°.

[0064] Furthermore, in the electrode tube 200, the tubular diaphragm 210 serves as an ion transport layer, used to isolate the inner and outer electrodes and the gas while conducting ions. Its material is preferably a modified polyphenylene sulfide composite material or other alkali-resistant, high-temperature-resistant, high-performance polymer materials commonly used in this technical field, such as Zirfon AG™ and PPS / ZrO2.

[0065] Both the inner electrode 220 and the outer electrode 230 include an electrode substrate and a catalyst layer. The catalyst layer is bonded to the electrode substrate by coating, sintering, deposition, or integral molding. The catalyst layer material is selected from one or more nickel-based materials, such as Raney nickel or Ni-Mo-based catalysts; the electrode substrate material can be selected from one or more of stainless steel, iron, and nickel, such as perforated nickel plates or nickel mesh.

[0066] Furthermore, in the bubble coalescence guiding structure 300, the support column 310 is fixed to the center of the electrode tube 200 by welding or stainless steel screws, providing welding points for the braided inner part 320 and the spiral flow channel 330; the braided inner part 320 and the spiral flow channel 330 are fixed to the support column 310 by welding, and the weld is sprayed with tantalum coating or covered with PTFE (polytetrafluoroethylene) lining to prevent the gap from being corroded by the electrolyte.

[0067] Furthermore, the tubular electrolytic cell 10 has a cylindrical structure with a diameter of 1500 mm to 2500 mm and a height of 1600 mm to 1800 mm;

[0068] The electrode tube 200 has an inner diameter of 100 mm to 160 mm, an outer diameter of 110 mm to 180 mm, a tube thickness of 10 mm to 40 mm, and a height of 1400 mm to 1600 mm.

[0069] Furthermore, the diameter of the support column 310 is 50 mm to 80 mm, and the height is 1350 mm to 1550 mm; the material of the support column is selected from nickel, stainless steel, and nickel-iron-chromium alloy.

[0070] The length of the woven inner part 320 at the lower part of the support column 310 is 200 mm to 250 mm, and the distance between it and the bottom of the support column 310 is 200 mm to 300 mm.

[0071] The woven inner part 320 on the upper part of the support column 310 has a length of 200 mm to 250 mm and is installed close to the spiral flow channel 330.

[0072] Furthermore, the spiral flow channel 330 has a flow channel width of 95 mm to 155 mm and a height of 650 mm to 850 mm; the spiral flow channel 330 is made of one of nickel, stainless steel, and nickel-iron-chromium alloy.

[0073] like Figure 7 As shown, the working principle of the tubular electrolytic cell 10 is as follows:

[0074] On the one hand, the tube-side electrolyte flows from bottom to top through the tube-side inlet 110 of the tubular electrolytic cell 10. After electrolysis, the tube-side electrolyte becomes a gas-liquid mixture containing a large number of microbubbles.

[0075] As the microbubbles rise, they flow through the braided inner component 320. Due to the low wettability of the hydrophobic yarns in the braided inner component 320, it provides aggregation sites for the microbubbles at the micro level, continuously inducing the microbubbles to coalesce and grow. Meanwhile, the spiral upward flow channel structure formed by the braided inner component 320 at the macro level can induce larger bubbles to detach rapidly, reducing bubble accumulation and blockage. At the same time, it can also guide the fluid to rise in a spiral, improving the uniformity of fluid distribution.

[0076] Furthermore, the braided inner part 320 at the lower part of the support column 310 has a smaller porosity, which can better intercept microbubbles and promote their aggregation. Under the action of liquid phase drag, the bubbles rise along the spiral flow channel 330 and aggregate and grow. The spiral flow channel 330 provides a spiral upward channel for the gas and liquid phases, so that the fluid flows uniformly in the tube side channel, fully contacts the electrode 220 inside the tube, enhances the mass and heat transfer process, and improves the electrolysis efficiency. Finally, because the braided inner part 320 at the upper part of the support column 310 has a larger porosity, the large bubbles formed by aggregation can be quickly detached without causing pore blockage.

[0077] On the other hand, the shell-side electrolyte enters from the bottom of the tubular electrolytic cell 10 and flows upward in the shell-side channel, washing the outer surface of all electrode tubes 200. The bubbles generated by electrolysis are efficiently carried away by the flowing shell-side electrolyte.

[0078] During the electrolysis process, the flow rate of the electrolyte in the tubular electrolytic cell 10 is 0.03 m / s to 0.07 m / s, and the current density is 250 A / m² to 800 A / m²; under normal pressure, the operating temperature of the tubular electrolytic cell 10 is 55 ℃ to 85 ℃.

[0079] Example 2

[0080] like Figure 8 As shown, the electrolysis apparatus of this embodiment includes the tubular electrolytic cell 10 of the above embodiment 1, and a first circulation unit and a second circulation unit arranged in parallel;

[0081] The first circulation unit includes a first gas-liquid separator 20, a first alkaline solution mixer 30 and a first circulation pump 40 connected in sequence. The inlet of the first gas-liquid separator 20 and the outlet of the first circulation pump 40 are respectively connected to the inlet and outlet of the tube side channel of the tubular electrolyzer 10 to realize the circulation of the tube side electrolyte.

[0082] The second circulation unit includes a second gas-liquid separator 50, a second alkaline solution mixer 60 and a second circulation pump 70 connected in sequence. The inlet of the second gas-liquid separator 50 and the outlet of the second circulation pump 70 are respectively connected to the inlet and outlet of the shell-side channel of the tubular electrolyzer 10 to realize the circulation of the shell-side electrolyte.

[0083] The gas phase outlets of the first gas-liquid separator 20 and the second gas-liquid separator 30 are respectively connected to a gas processing device 80 to receive the separated gas for drying and pressurization, which facilitates subsequent data analysis.

[0084] It should be noted that the first gas-liquid separator 20, the first alkaline solution mixer 30, the first circulating pump 40, the second gas-liquid separator 50, the second alkaline solution mixer 60, the second circulating pump 70, and the gas processing equipment 80 mentioned above are all conventional equipment in the field and can be selected according to actual needs. Their specific structures will not be described in detail here.

[0085] In the aforementioned electrolysis apparatus, the shell-side electrolyte and the tube-side electrolyte from the tubular electrolytic cell 10 undergo gas-liquid separation. The separated gas is then dried and pressurized, and the treated gas can be stored and used. The separated electrolyte is returned to the corresponding shell-side and tube-side channels to achieve electrolyte circulation.

[0086] Example 3

[0087] The electrolysis apparatus described in Example 1 was used to electrolyze a 30 wt% potassium hydroxide solution to generate hydrogen and oxygen. The electrolyte inlet volumetric flow rate was set to 56000 mL / min, the electrolyte flow rate was 0.05 m / s, the current density was 312.5 A / m², and the electrolysis cell operating temperature was 70 ℃.

[0088] In the tubular electrolytic cell of this embodiment, the bubble coalescence guiding structure includes a braided inner part with a porosity of 85% at the lower part of the support column, a braided inner part with a porosity of 95% at the upper part, and a spiral flow channel located between the braided inner parts. The spiral angle of the spiral flow channel is 30°, and the material of the spiral flow channel is nickel.

[0089] The flow channel of the braided inner component forms a 30° angle with the horizontal plane. In the braided inner component, the hydrophilic yarns are made of nickel, and the hydrophobic yarns are made of polytetrafluoroethylene (PTFE). The spacing between each yarn is 0.5 mm, the diameter of both hydrophilic and hydrophobic yarns is 120 μm, the braiding density is 80 mesh, and the volume ratio of hydrophilic to hydrophobic yarns is 3:1.

[0090] Example 4

[0091] This embodiment is basically the same as the tubular electrolytic cell and electrolysis conditions in Embodiment 3, except that a spiral flow channel is not installed in the bubble coalescence guiding structure.

[0092] Comparative Example 1

[0093] This comparative example is basically the same as the tubular electrolyzer and electrolysis conditions in Example 3, except that the bubble coalescence and flow guiding structure is not used.

[0094] Comparative Example 2

[0095] This embodiment is basically the same as the tubular electrolytic cell and electrolysis conditions in Embodiment 3. The difference is that, in the bubble coalescence guiding structure, the upper part of the support column is not equipped with braided internals.

[0096] Comparative Example 3

[0097] This embodiment is basically the same as the tubular electrolytic cell and electrolysis conditions in Embodiment 3. The difference is that the lower part of the support column is not equipped with braided internals in the bubble coalescence guiding structure.

[0098] The bubble size and gas holdup in the top tube electrolyte of the tubular electrolyzers of Examples 3-4 and Comparative Examples 1-3 after electrolysis are shown in Table 1 below. A comparison of gas holdup and energy consumption of the tubular electrolyzers of Example 3 and Comparative Example 1 at different apparent flow rates is also provided. Figure 9 and Figure 10 As shown.

[0099] Table 1

[0100]

[0101] As can be seen from the results in Table 1, Examples 3 and 4, employing the bubble coalescence and flow guiding structure of the present invention, can significantly increase the bubble size in the tube-side electrolyte, reducing it to the millimeter scale. Larger bubbles rise faster, thereby driving the bubble cluster to dissipate and reducing the gas holdup. Furthermore, by adding spiral flow channels between the braided inner components, the bubble removal effect can be further improved, with a gas holdup as low as 6%. In contrast, Comparative Example 1, which does not employ the bubble coalescence and flow guiding structure, has bubble sizes of only 100µm~900µm and a gas holdup as high as 17%. Figure 9 and Figure 10 It can be seen that, under different apparent flow rates, the gas holdup and energy consumption of Comparative Example 1 are much higher than those of Example 3.

[0102] Furthermore, comparing Example 3, Comparative Example 2, and Comparative Example 3, it can be seen that when woven inner components are only provided at the upper or lower part of the support column, the bubble coalescence effect is poor. When no woven inner components are provided at the lower part of the support column, large bubbles cannot coalesce to form a group of small bubbles that then dissipate, resulting in a higher gas content. However, when no woven inner components are provided at the upper part of the support column, secondary induced coalescence is lacking, resulting in a lower bubble size and a higher gas content compared to Example 3.

[0103] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A tubular electrolytic cell for enhanced bubble coalescence and separation, characterized in that, The tubular electrolysis includes a shell and a plurality of electrode tubes disposed within the shell, as well as a tube sheet for fixing the electrode tubes; The electrode tube includes a tubular diaphragm, and an inner electrode and an outer electrode respectively disposed on the inner and outer surfaces of the tubular diaphragm. The inner electrode forms a tube-side channel, and the outer side of the outer electrode, the inner wall of the shell, and the tube sheet form a shell-side channel. The tube passage is also equipped with a bubble coalescence guiding structure to induce the growth and outflow of microbubbles generated by electrolysis; the bubble coalescence guiding structure includes a support column and a braided inner component fixed to the upper and lower parts of the support column; the braided inner component is made of hydrophilic and hydrophobic yarns, wherein: The hydrophilic and hydrophobic threads are spirally wound to form braided threads, which are braided in an M-shape to form a braided inner part with multiple flow channels on a macroscopic scale; the braided inner part is spirally wound on the support column.

2. The tubular electrolytic cell for enhanced bubble coalescence and separation according to claim 1, characterized in that, The angle α between the flow channel of the woven inner part and the horizontal plane is set to 20° < α < 65°.

3. The tubular electrolytic cell for enhanced bubble coalescence and separation according to claim 1, characterized in that, The volume ratio of the hydrophilic filaments to the hydrophobic filaments is 2:1 to 6:1, and the diameter of the hydrophilic or hydrophobic filaments is 80 μm to 200 μm. The hydrophilic filament is made of one or more of the following materials: platinum, nickel, graphene, titanium, and stainless steel. The hydrophobic filaments are made of one or more of polytetrafluoroethylene, polyvinylidene fluoride, polyolefins, and polyamides.

4. The tubular electrolytic cell for enhanced bubble coalescence and separation according to claim 1, characterized in that, In the braided inner component, the spacing between the hydrophilic or hydrophobic threads is 0.1 mm to 1.0 mm; the braiding density is 50 to 200 mesh; the porosity of the braided inner component at the lower part of the support column is 83% to 87%; and the porosity of the braided inner component at the upper part is 90% to 95%.

5. The tubular electrolytic cell for enhanced bubble coalescence and separation according to claim 1, characterized in that, The bubble coalescence and flow guiding structure also includes a spiral flow channel disposed on the support column. The spiral flow channel is located between the upper and lower woven inner parts, and the spiral angle of the spiral flow channel is 20° to 65°. The spiral flow channel has a width of 95 mm to 155 mm and a height of 650 mm to 850 mm; the spiral flow channel is made of one of nickel, stainless steel, and nickel-iron-chromium alloy.

6. The tubular electrolytic cell for enhanced bubble coalescence and separation according to claim 1, characterized in that, The tubular electrolytic cell has a cylindrical structure with a diameter of 1500 mm to 2500 mm and a height of 1600 mm to 1800 mm. The electrode tube has an inner diameter of 100 mm to 160 mm, an outer diameter of 110 mm to 180 mm, a tube thickness of 10 mm to 40 mm, and a height of 1400 mm to 1600 mm.

7. The tubular electrolytic cell for enhanced bubble coalescence and separation according to claim 5, characterized in that, The diameter of the support column is 50 mm to 80 mm, and the height is 1350 mm to 1550 mm; the material of the support column is selected from nickel, stainless steel, and nickel-iron-chromium alloy. The length of the woven inner part at the lower part of the support column is 200 mm to 250 mm, and the distance between it and the bottom of the support column is 200 mm to 300 mm. The length of the woven inner part on the upper part of the support column is 200 mm to 250 mm, and it is installed close to the spiral flow channel.

8. An electrolysis method using the tubular electrolytic cell according to any one of claims 1 to 7, characterized in that, The electrolysis method includes the following steps: The electrolyte enters the tube-side channel from the bottom of the tubular electrolyzer and flows upward. After electrolysis, the electrolyte becomes a gas-liquid mixture containing a large number of microbubbles. As the microbubbles rise, they pass through the braided inner components. Due to the low wettability of the hydrophobic threads in the braided inner components, they provide aggregation sites for the microbubbles at the microscopic level, continuously inducing the microbubbles to coalesce and grow. Meanwhile, the spiral upward flow channel structure formed by the braided inner components at the macroscopic level induces larger bubbles to detach rapidly, reducing bubble accumulation and blockage. The shell-side electrolyte enters from the bottom of the tubular electrolytic cell and flows upward in the shell-side channel, washing the outer surface of all electrode tubes. The bubbles generated by electrolysis are efficiently carried away by the flowing shell-side electrolyte.

9. The electrolysis method according to claim 8, characterized in that, The flow rate of the electrolyte in the tubular electrolytic cell is 0.03 m / s to 0.07 m / s, and the current density is 250 A / m² to 800 A / m². Under normal pressure, the operating temperature of the tubular electrolytic cell is 55℃ to 85℃.

10. An electrolysis apparatus, characterized in that, The electrolysis device includes the tubular electrolytic cell according to any one of claims 1 to 7, and the electrolysis device includes the above-mentioned tubular electrolytic cell, and a first circulation unit and a second circulation unit arranged in parallel; The first circulation unit includes a first gas-liquid separator, a first alkaline solution mixer and a first circulation pump connected in sequence. The inlet of the first gas-liquid separator and the outlet of the first circulation pump are respectively connected to the inlet and outlet of the tube side channel of the tubular electrolyzer to realize the circulation of the tube side electrolyte. The second circulation unit includes a second gas-liquid separator, a second alkaline solution mixer, and a second circulation pump connected in sequence. The inlet of the second gas-liquid separator and the outlet of the second circulation pump are respectively connected to the inlet and outlet of the shell-side channel of the tubular electrolyzer to realize the circulation of the shell-side electrolyte. The gas phase outlets of the first gas-liquid separator and the second gas-liquid separator are respectively connected to a gas processing device.

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