Dispersing device for membrane casting solution

Abstract

The utility model provides the dispersing device for the membrane casting liquid, which adopts the frame-type stirring kettle to replace a traditional high-speed shearing device, so that thick slurry can be fully mixed, the dispersity of the membrane casting liquid is improved, and the preparation quality of a composite membrane is improved; the hollow stainless steel pipe with the screen is arranged in the stirring frame, the screen is also distributed on the stirring shaft, the vacuum device can vacuumize slurry in the stirring kettle through the screen distributed on the stirring shaft and / or the hollow stainless steel pipe, and inorganic powder in a membrane casting solution can be effectively prevented from entering the vacuum pipe; therefore, the purity of the membrane casting solution is ensured. The device disclosed by the utility model is used for vacuumizing while stirring raw materials, and the prepared composite diaphragm and inorganic hydrophilic material are uniformly dispersed, uniform and compact in pore passage, high in bubble point pressure and low in hydrogen permeability.

Description

Technical Field

[0001] The utility model relates to the technical field of hydrogen production by electrolyzing water, and specifically to a dispersion device for casting solution. Background Art

[0002] The technology of hydrogen production by electrolyzing water has become a research hotspot for hydrogen production due to its cleanliness and high efficiency. Its core component - the composite diaphragm for hydrogen production by electrolyzing water, whose performance directly affects the electrolysis efficiency, hydrogen purity and equipment life. An ideal diaphragm needs to have excellent ion conductivity, airtightness and mechanical strength to ensure the stable and efficient electrolysis process.

[0003] With the development of materials science, the preparation technology of composite diaphragms has made significant progress. The phase inversion method for film formation, as the mainstream, realizes the optimization of the microstructure of the diaphragm by precisely controlling the composition and process of the casting solution, thereby improving the overall performance. However, in the pursuit of high-performance composite diaphragms, a series of technical challenges are also faced.

[0004] In response to the need to improve the hydrophilicity of the composite diaphragm, the existing technical solutions generally adopt the method of adding a large amount of inorganic hydrophilic particles (such as zirconia) to the casting solution. However, due to the high density and easy agglomeration characteristics of zirconia particles, their dispersion stability in the casting solution has become a major problem.

[0005] In addition, the viscosity of the casting solution is relatively high, and a large amount of gas will inevitably be mixed in during the configuration process, generating a large number of bubbles. If these bubbles cannot be effectively removed, there will be pinholes on the surface of the polymer film, seriously affecting the forming quality and final performance of the diaphragm.

[0006] Therefore, the existing technology usually adopts the high-speed shear mixing technology to try to achieve the uniform dispersion of the casting solution, and removes the bubbles by standing or vacuum degassing. Although high-speed shear can improve the dispersibility of particles to a certain extent, during the long-term standing or vacuum degassing process, due to the gravity effect, the inorganic particles may still settle, resulting in uneven composition of the upper and lower parts of the casting solution.

[0007] Moreover, whether it is standing or vacuum degassing, as described in CN116803475A, it is difficult to completely remove the fine bubbles in the casting solution, especially inside the resin (the pore distribution is uneven). These remaining bubbles will expand into pores during the diaphragm forming process, resulting in larger pore diameters on the diaphragm surface, reduced airtightness, and affecting the electrolysis efficiency and hydrogen purity.

[0008] In addition, dispersing the casting solution through multiple steps such as high-speed shear, standing or vacuum degassing not only makes the operation cumbersome, but also increases the production cost and the difficulty of quality control. Content of the Utility Model

[0009] In order to solve the deficiencies of the existing technology, the utility model provides a dispersion device for casting solution, including:

[0010] Stirring kettle, connected to the raw material supply system, for mixing raw materials to obtain a mixed slurry,

[0011] Among them, the components of the stirring kettle include:

[0012] Stirring shaft, which is of a hollow structure and is distributed with a sieve mesh thereon,

[0013] Stirring frame, fixedly connected to the stirring shaft, and internally provided with a hollow stainless steel pipe,

[0014] The hollow stainless steel pipes are arranged crosswise and are distributed with a sieve mesh thereon,

[0015] Stirring motor, connected to the stirring shaft, for driving the stirring shaft to drive the stirring frame to rotate,

[0016] Shell, provided on the outside of the stirring kettle, for loading other components of the stirring kettle; vacuum device, connected to one end of the stirring kettle, for performing vacuum defoaming treatment on the mixed slurry in the stirring kettle to obtain a casting solution;

[0017] Delivery pipeline, connected to the other end of the stirring kettle, for transporting the casting solution that has been dispersed in the stirring kettle to the outside.

[0018] Preferably, the raw materials include one or several combinations of inorganic powder, resin, dispersant and solvent.

[0019] Preferably, the inorganic powder is an inorganic hydrophilic powder. For example, the inorganic hydrophilic powder can be one or several combinations of ultrafine silica, bentonite, diatomite, iron oxide, boehmite, aluminum hydroxide, zirconium oxide.

[0020] Preferably, the particle size of the inorganic powder is ≥21 nm, preferably ≥16 nm, and more preferably ≥11 nm.

[0021] Preferably, the resin can be a polymer alloy composed of one or several of polyphenylene sulfide, polysulfone, polyethersulfone, polyimide, polyetheretherketone, polyvinylidene fluoride, polyolefin.

[0022] More preferably, the resin forms a diaphragm matrix.

[0023] More preferably, the diaphragm matrix can be one layer or multiple layers (two or more layers) of resin.

[0024] More preferably, the resin can be a polyolefin matrix.

[0025] Specifically, the polyolefin matrix can be a polyethylene diaphragm matrix, a polypropylene diaphragm matrix, a polyethylene - polypropylene double - layer diaphragm matrix or a polyethylene - polypropylene - polyethylene three - layer diaphragm matrix.

[0026] Preferably, the solvent includes one or more of water, alcohol, ether, ester, ketone, nitrile, alkane, halogenated hydrocarbon, and aromatic hydrocarbon, and is preferably a solvent selected from one or a combination of more than one of the following: water, N,N-dimethylformamide, methanol, ethanol, ether, tetrahydrofuran, acetonitrile, valeronitrile, methoxypropionitrile, butyronitrile, adiponitrile, phenylacetonitrile, chloroacetonitrile, acetone, cyclohexane, dichloromethane, chloroform, carbon tetrachloride, ethyl acetate, acetone, N-methylpyrrolidone, toluene, and petroleum ether.

[0027] Preferably, the raw material further includes an organic binder.

[0028] More preferably, the organic binder is at least one of the following chemical substances: polyvinyl alcohol, polytetrafluoroethylene, polyvinylidene fluoride, modified styrene-butadiene rubber (modified SBR), fluororubber, and polyurethane.

[0029] Preferably, the shape of the sieve on the stirring shaft can be one or a combination of several of the following: circular sieve holes, square sieve holes, hexagonal sieve holes, triangular sieve holes, and mesh sieve (non-single-shaped holes).

[0030] More preferably, the aperture of the sieve on the stirring shaft is ≤20 nm, preferably ≤15 nm, and more preferably ≤10 nm.

[0031] Preferably, the connection method between the stirring shaft and the stirring frame is selected from one or a combination of several of the following: welding, bolt connection, pin connection, binder connection, and key connection.

[0032] Preferably, the width of the stirring frame is 1 / 4 - 5 / 6 of the diameter of the stirring kettle, preferably 1 / 3 - 4 / 5, and more preferably 1 / 2 - 3 / 4.

[0033] Preferably, the height of the stirring frame is 1 / 4 - 5 / 6 of the height of the stirring kettle, preferably 1 / 3 - 4 / 5, and more preferably 1 / 2 - 3 / 4.

[0034] Preferably, the pipe diameter of the hollow stainless steel pipe is 5 - 150 mm, preferably 10 - 120 mm, and more preferably 20 - 100 mm.

[0035] Preferably, the wall thickness of the hollow stainless steel pipe is 1 - 15 mm, preferably 2 - 12 mm, and more preferably 3 - 10 mm.

[0036] Preferably, the shape of the sieve on the hollow stainless steel pipe can be one or a combination of several of the following: circular sieve holes, square sieve holes, hexagonal sieve holes, triangular sieve holes, and mesh sieve (non-single-shaped holes).

[0037] More preferably, the aperture of the sieve on the hollow stainless steel pipe is ≤20 nm, preferably ≤15 nm, and more preferably ≤10 nm.

[0038] More preferably, the shape of the sieve on the stirring shaft may be the same as or different from the shape of the sieve on the hollow stainless steel tube.

[0039] More preferably, the aperture size of the sieve on the stirring shaft may be the same as or different from the aperture size of the sieve on the hollow stainless steel tube.

[0040] In a preferred embodiment, the vacuum device is respectively connected to the sieve on the stirring shaft and / or the sieve on the hollow stainless steel tube, and the raw materials in the stirring kettle are evacuated through the sieve on the stirring shaft and / or the sieve on the hollow stainless steel tube.

[0041] In a preferred embodiment, the stirring frame is a solid stainless steel frame.

[0042] In a preferred embodiment, the vacuum device is selected from one or a combination of several of the following: vacuum pump, vacuum generator, vacuum unit, vacuum coating machine, vacuum furnace, vacuum packaging machine, vacuum drying oven, vacuum valve, vacuum storage tank, vacuum filter.

[0043] Preferably, the vacuum pump is selected from one or a combination of several of the following: reciprocating vacuum pump, rotary vacuum pump, momentum transfer pump.

[0044] Preferably, the material of the conveying pipeline is selected from one or a combination of several of the following: stainless steel, polypropylene, polyethylene, polytetrafluoroethylene, polyvinyl chloride, glass, ceramic.

[0045] In a preferred embodiment, the method of using the dispersion device for the casting solution comprises the steps of:

[0046] Adding raw materials into the stirring kettle, starting the stirring motor, and starting stirring;

[0047] Starting the vacuum device, setting the vacuum degree to a preset value, removing the bubbles in the slurry, and obtaining a casting solution with uniform dispersion and low foam;

[0048] After the vacuum evacuation is completed, stop stirring, open the discharge port of the stirring kettle, and convey the uniformly dispersed casting solution to the coating equipment through the conveying pipeline.

[0049] In a preferred embodiment, the stirring speed of the stirring motor is 20 - 200 r / min, preferably 50 - 150 r / min, and more preferably 80 - 100 r / min.

[0050] In a preferred embodiment, the stirring time of the stirring motor is 0.5 - 5 h, preferably 1 - 4 h, and more preferably 2 - 3 h.

[0051] In a preferred embodiment, the degree of vacuum is (-0.3)-(-0.1) MPa, preferably (-0.4)-(-0.1) MPa, more preferably (-0.5)-(-0.1) MPa.

[0052] In a preferred embodiment, in the slurry, the addition amount (mass fraction) of the organic binder is 1-20%, preferably 3-15%, more preferably 5-10%.

[0053] In a preferred embodiment, in the slurry, the addition amount (mass fraction) of the inorganic powder is 1-20%, preferably 3-15%, more preferably 5-10%.

[0054] Preferably, the casting solution is used to prepare a polymer separator by the phase inversion film formation method.

[0055] Specifically, the phase inversion film formation method includes one or more combinations of immersion precipitation phase inversion method, thermal induced phase inversion method, vapor induced phase inversion method, and solvent evaporation gel method.

[0056] More preferably, the thickness of the polymer separator is 50-500 μm, preferably 80-400 μm, more preferably 100-300 μm.

[0057] More preferably, the porosity of the polymer separator is 20-80%, preferably 30-70%, more preferably 40-60%.

[0058] The beneficial effects of the present utility model are as follows:

[0059] The present utility model provides a dispersion device for a casting solution. A stirring kettle with frame stirring is adopted to replace the traditional high-speed shearing device, which can fully mix the viscous slurry, improve the dispersion of the casting solution, and thus improve the preparation quality of the composite separator; a hollow stainless steel pipe with a screen is arranged in the stirring frame, and the stirring shaft is also distributed with a screen. The vacuum device can not only evacuate the slurry in the stirring kettle through the screens distributed on the stirring shaft and / or the hollow stainless steel pipe, but also effectively prevent the inorganic powder in the casting solution from entering the vacuum tube, thereby ensuring the purity of the casting solution. The device of the present utility model evacuates the vacuum while stirring the raw materials. The prepared composite separator has uniform dispersion of the inorganic hydrophilic material, uniform and dense pores, high bubble point pressure, and low hydrogen permeability. Description of the Drawings

[0060] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0061] Figure 1 It is a schematic structural diagram of the device in Embodiment 1 of the present invention.

[0062] The description of the reference numerals is as follows:

[0063] 1. Stirring kettle; 101. Stirring shaft; 102. Stirring frame; 103. Hollow stainless steel pipe;

[0064] 104. Shell; 2. Vacuum device; 3. Delivery pipeline. Detailed implementation manners

[0065] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0066] It should be noted that if there are directional indications (such as up, down, left, right, front, back,...) involved in the embodiments of the present invention, then the directional indications are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0067] In the present invention, unless otherwise clearly defined and limited, terms such as "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0068] In addition, if descriptions such as "first" and "second" are involved in the embodiments of the present utility model, the descriptions of "first", "second", etc. are only for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and / or" appearing throughout the text includes three parallel scenarios. Taking "A and / or B" as an example, it includes Scenario A, or Scenario B, or the scenario where both A and B are satisfied simultaneously. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0069] Embodiment 1

[0070] This embodiment provides a dispersion device for a casting solution, as Figure 1 shown, including: a stirring kettle 1, including:

[0071] A stirring shaft 101: designed as a hollow structure and having a screen with a pore size less than 10 nm distributed on its surface, which not only reduces the weight of the stirring shaft but also allows vacuum suction to be carried out through the inside of the stirring shaft during the stirring process, helping to remove air bubbles in the slurry.

[0072] A stirring frame 102: welded to the stirring shaft 101 and having hollow stainless steel tubes 103 arranged crosswise inside. The hollow stainless steel tubes 103 also have a screen with a pore size less than 10 nm distributed on them to prevent inorganic powder in the slurry from entering the tubes and at the same time assist in the vacuum degassing process. The stirring frame 102 is made of a solid stainless steel frame and is designed as a frame-type stirrer for high-viscosity slurry to improve the stirring efficiency and dispersion effect.

[0073] A stirring motor: connected to the stirring shaft 102, providing power to drive the rotation of the stirring shaft and the stirring frame to achieve uniform mixing of the slurry.

[0074] A housing 104: provided on the outside of the stirring kettle 1, used to load other components of the stirring kettle 1 and protect the internal equipment from the external environment.

[0075] A vacuum device 2, connected to one end of the stirring kettle 1, and performing vacuum degassing treatment on the mixed slurry in the stirring kettle 1 through the screens in the stirring shaft 101 and the hollow stainless steel tubes 103.

[0076] A conveying pipeline 3, connected to the other end of the stirring kettle 1, responsible for conveying the uniformly dispersed and vacuum-degassed casting solution to an external coating device.

[0077] Embodiment 2

[0078] This embodiment provides a method for using the device described in Embodiment 1.

[0079] Among them, the raw materials are selected as follows:

[0080] (1) Inorganic hydrophilic powder: A combination of ultrafine silica and bentonite is selected to improve the hydrophilicity and mechanical strength of the separator.

[0081] (2) Resin: A polymer alloy of polyphenylene sulfide and polyethersulfone is used as the matrix material to ensure the chemical corrosion resistance and thermal stability of the separator.

[0082] (3) Solvent: A mixed solvent of water and N,N-dimethylformamide is selected to optimize the dissolution effect and subsequent drying process.

[0083] (4) Organic binder: An appropriate amount of polyvinyl alcohol is added as the binder to improve the overall bonding strength of the separator.

[0084] The steps of the usage method include:

[0085] S1. Add the slurry prepared in Step 1 into the stirring kettle, start the stirring motor, with a stirring speed of 100 r / min and a stirring time of 30 minutes.

[0086] S2. Start the vacuum device, set the vacuum degree to -0.1 MPa and the vacuum time to 30 minutes. Evacuate the inside of the stirring kettle through the vacuum device to remove the bubbles in the slurry.

[0087] After the vacuum evacuation is completed, stop the stirring, open the discharge port of the stirring kettle 1, and transport the uniformly dispersed casting solution to the coating equipment through the conveying pipeline 3.

[0088] Comparative Example 1

[0089] This comparative example prepares the casting solution by the method of static defoaming. The steps include:

[0090] Use the same stirring kettle 1 as in Example 2 for the preliminary mixing of the casting solution, but do not connect the vacuum device.

[0091] After the mixing is completed, transfer the casting solution to another container for static defoaming treatment, with a static time of 30 min.

[0092] Comparative Example 2

[0093] This comparative example prepares the casting solution by the method of vacuum defoaming. The steps include:

[0094] Adopt a traditional vacuum defoaming device, which has a vacuum pump and a corresponding sealed container.

[0095] Pour the prepared casting solution (obtained by mixing through a high-speed shearing device) into a sealed container, seal it, and connect a vacuum pump.

[0096] Turn on the vacuum pump to evacuate the container. Set the evacuation time to 30 minutes to remove the bubbles in the casting solution.

[0097] After degassing is completed, stop evacuating, and take out the casting solution for subsequent coating operations.

[0098] Prepare polymer films from the casting solutions of Example 2, Comparative Example 1, and Comparative Example 2 by coating. Characterize the properties of these polymer films, and the results are shown in Table 1.

[0099] Table 1. Characterization results of the diaphragm properties obtained from the casting solutions of Example 1, Comparative Example 1, and Comparative Example 2

[0100]

[0101] As can be seen from Table 1, the dispersion device of the casting solution of the present utility model can significantly improve the preparation quality of the casting solution for the electrolytic water hydrogen production composite diaphragm. The pore size is small, with a maximum of only 89 nm, the bubble point pressure is as high as 3.1 bar, the contact angle is only 32°, and the hydrogen permeability is low, thereby improving the electrolysis efficiency and hydrogen production.

[0102] At the same time, since Example 2 performs stirring and vacuum degassing simultaneously, it overcomes the defects of traditional static degassing and vacuum degassing, and can be widely applied to the preparation process of other chemical products to improve the purity and quality of the products.

[0103] Moreover, in the field of material processing, the dispersion device of the present utility model can effectively solve problems such as uneven slurry mixing and bubble residue during the material processing process, improve the processing quality and efficiency of the material, and make the pore channels of the material dense and uniform.

[0104] The above are only the preferred embodiments of the present utility model, and do not limit the patent scope of the present utility model accordingly. Any equivalent structural transformation made under the inventive concept of the present utility model by using the content of the specification and drawings of the present utility model, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present utility model.

Claims

1. A dispersion device for a casting solution, characterized in that, Including: A stirring kettle, connected to a raw material supply system, for mixing raw materials to obtain a mixed slurry, wherein the components of the stirring kettle include: A stirring shaft, which is of a hollow structure and is distributed with a sieve on it, A stirring frame, fixedly connected to the stirring shaft, and internally provided with hollow stainless steel pipes, the hollow stainless steel pipes are arranged in a cross pattern and are distributed with a sieve on them, A stirring motor, connected to the stirring shaft, for driving the stirring shaft to drive the stirring frame to rotate, A housing, arranged outside the stirring kettle, for loading other components of the stirring kettle; A vacuum device, communicated with one end of the stirring kettle, for performing vacuum defoaming treatment on the mixed slurry in the stirring kettle to obtain a casting solution; A conveying pipeline, communicated with the other end of the stirring kettle, for conveying the casting solution dispersed in the stirring kettle to the outside.

2. The device according to claim 1, wherein The raw materials include one or several combinations of inorganic powder, resin, dispersant and solvent.

3. The device according to claim 1, characterized in that, The aperture of the sieve on the stirring shaft is ≤ 10 nm.

4. The device according to claim 1, characterized in that The connection mode between the stirring shaft and the stirring frame is selected from one or several combinations of welding, bolt connection, pin connection, binder connection, key connection.

5. The device according to claim 1, characterized in that, The width of the stirring frame is 1 / 2 - 3 / 4 of the diameter of the stirring kettle.

6. The device according to claim 1, characterized in that, The pipe diameter of the hollow stainless steel pipe is 20 - 100 mm.

7. The device according to claim 1, characterized in that, The aperture of the sieve on the hollow stainless steel pipe is ≤ 10 nm.

8. The device according to claim 1, characterized in that The vacuum device is respectively communicated with the sieve on the stirring shaft and the sieve on the hollow stainless steel pipe.

9. The device according to claim 1, characterized in that, The stirring frame is a solid stainless steel frame.

10. The device according to claim 1, characterized in that, The material of the conveying pipeline is selected from one or several combinations of stainless steel, polypropylene, polyethylene, polytetrafluoroethylene, polyvinyl chloride, glass, ceramic.

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