Preparation system of metal fiber felt microporous layer for PEM electrolytic water hydrogen production

Abstract

The utility model discloses a kind of preparation systems of PEM electrolytic water hydrogen production with metal fiber felt microporous layer, including spraying chamber and setting chamber, the spraying chamber is connected with setting chamber and is communicated and is formed into forming channel for conveying component to pass through, the conveying component is used to send fiber felt along forming channel, the spraying chamber includes several spray guns, slurry mixed with coating is atomized after the spray gun and evenly covered on metal fiber felt base material for forming microporous layer;The setting chamber includes heating unit, the heating unit is designed to, the spray coating for forming microporous layer on the fiber felt is dried to set. The utility model is reasonable in structure, high efficiency, low in cost and microporous layer with gradient pore size can be formed conveniently.

Description

Technical Field

[0001] This utility model relates to the field of PEM electrolysis for hydrogen production technology, specifically a preparation system for a metal fiber felt microporous layer for PEM electrolysis for hydrogen production. Background Technology

[0002] The combination of metal diffusion layers and microporous layers (MPLs) has wide applications in various fields, especially in energy, environmental protection, and chemical engineering. For example, in fuel cells, it can be used as a gas diffusion layer (GDL), water management layer, gas transport layer, and thermal management layer; in PEM water electrolysis for hydrogen production, it can be used as an electrode material, a membrane material for gas-liquid separation, or a catalyst support; in hydrogen purification and filtration, it can be used for multi-stage filtration of impurities and adsorbent supports in hydrogen. Among these, microporous layers with gradient pore sizes have significant advantages and perform better as gas diffusion layers (GDLs) in various fields, especially in PEM water electrolysis for hydrogen production.

[0003] In existing technologies, metal diffusion layers typically utilize metal fiber felt boards. Metal powder is applied as a coating onto the metal fiber felt board to create a microporous layer. The methods for preparing this microporous layer generally include the following: one is plasma spraying, specifically atmospheric plasma spraying and vacuum plasma spraying. Atmospheric plasma spraying is performed in an atmospheric environment, where the coating is easily oxidized due to the influence of oxygen and the high temperature of the spray gun. The resulting oxides affect the electrochemical properties of the microporous layer, reducing its conductivity. Vacuum plasma spraying, on the other hand, requires operation in a vacuum environment, which is not only expensive but also necessitates repeated vacuuming, resulting in low production efficiency and significantly increased production costs. Furthermore, the uniformity of the microporous layer prepared by plasma spraying in existing technologies is only 10-20% of the spray thickness, indicating poor uniformity.

[0004] Another method is the scraping coating method. Under normal temperature and pressure, a slurry mixed with paint is evenly applied to the base of the metal fiber felt board. Subsequent processing forms a microporous layer. While this method avoids paint oxidation, the uniformity of the coating after application is only 3-10% of the coating thickness. However, this method limits the scraping area, and complete coverage scraping can lead to slurry overflow and waste. Furthermore, the paint suspension in the slurry is poor, and only one type of microporous layer with a specific pore size can be formed in a single scraping, making continuous production impossible. Preparing microporous layers with gradient pore sizes has a long production cycle and high cost. Additionally, because metal fiber felt boards possess… Due to its porous structure and excellent liquid diffusion capabilities, the dry fiber felt board easily absorbs a large amount of solution during scraping, causing an imbalance in the paint-to-solvent ratio and making it impossible to achieve a smooth scraped surface. Furthermore, while wetting the fiber felt board for scraping can ensure a healthy paint-to-solvent ratio and good results in the first half, the solvent accumulates as the scraper advances in the second half, leading to excessive solvent and disrupting the uniform distribution of the paint, resulting in poor surface uniformity. Additionally, the scraping area is limited; increasing the area reduces both the scraping effect and uniformity. Utility Model Content

[0005] This utility model discloses a system for preparing a metal fiber felt microporous layer for PEM water electrolysis to produce hydrogen. It solves the technical problems of easy oxidation, high cost, and low efficiency in existing metal fiber felt microporous layer preparation processes. The system offers the advantages of a reasonable structure, high efficiency, low cost, and the ability to easily form microporous layers with gradient pore sizes. The technical solution adopted is as follows:

[0006] A system for preparing a microporous layer of metal fiber felt for PEM water electrolysis to produce hydrogen includes a spraying chamber and a setting chamber. The spraying chamber and the setting chamber are connected to form a forming channel through which a conveying component passes. The conveying component transports the fiber felt along the forming channel. The spraying chamber includes several spray guns, through which a slurry mixed with paint is atomized and uniformly applied to the metal fiber felt substrate to form a microporous layer. The setting chamber includes a heating unit designed to dry and set the sprayed layer on the fiber felt used to form the microporous layer. Preferably, the spraying chamber includes a spraying inlet and a spraying outlet, which are horizontally elongated to accommodate the conveying component and effectively isolate the spraying chamber from the external environment. Preferably, the setting chamber includes a setting inlet and a setting outlet, which are horizontally elongated to allow the conveying component to pass through and effectively isolate the setting chamber from the external environment. Preferably, the conveying assembly includes multiple length segments connected end to end, and each length segment can be driven separately to precisely control the speed at which the metal fiber felt substrate is conveyed forward along the forming channel, so as to match the different speed requirements of the substrate being conveyed forward in the spraying chamber or the shaping chamber.

[0007] Based on the above technical solution, several spray guns are arranged axially along the forming channel in the spraying chamber to spray and form a coating layer of a set thickness or to form multiple coating layers stacked together. Preferably, the several spray guns are divided into multiple groups, and the multiple groups of spray guns are arranged axially along the forming channel to spray coatings of one particle size or multiple particle sizes. When spraying coatings of one particle size, a coating layer with a set thickness can be formed. When spraying coatings of multiple particle sizes, multiple coating layers can be formed to obtain a microporous layer with different pore sizes.

[0008] Based on the above technical solution, the spray gun is positioned in the spraying chamber with adjustable vertical position and angle, and the spray gun includes an adjustment unit for adjusting the spraying speed and flow rate of the slurry.

[0009] Based on the above technical solution, the slurry mixed with paint is supplied to the spray gun via a diaphragm pump.

[0010] Based on the above technical solution, multiple sets of forming modules formed by the spraying chamber and the shaping chamber are arranged in parallel, and the forming channel runs through multiple sets of forming modules.

[0011] Based on the above technical solution, a dust removal chamber is also included. The forming channel extends through the dust removal chamber, and the conveying assembly transports the fiber felt through the dust removal chamber into the spraying chamber and the setting chamber. Preferably, the dust removal chamber is designed to achieve a cleanliness level of less than Class 1000, reducing the contact between external dust or particles and the metal fiber felt substrate. Preferably, the dust removal chamber includes an air inlet and a dust removal filter unit. The airflow introduced through the air inlet flows through the dust removal filter unit and, after filtration, can also blow away dust or other particles on the fiber felt substrate to achieve a dust removal effect.

[0012] Based on the above technical solution, a negative pressure environment is formed in the spraying chamber to prevent the slurry mixed with paint from overflowing. Preferably, the airflow formed in the spraying chamber flows from top to bottom, guiding the slurry mixed with paint downward to contact the metal fiber felt substrate, reducing slurry overflow or splashing, and facilitating the slurry to fall along a set path.

[0013] Based on the above technical solution, the spraying chamber is equipped with water curtains located on both sides of the conveying assembly, and two water tanks are provided below the spraying chamber to collect the slurry. Preferably, the bottom surface of the water tanks has an inclined angle, and the drain outlet of the water tanks is located at a lower position to guide the collected water mixed with slurry into the water collection tank.

[0014] Based on the above technical solution, the heating unit includes several heating resistance wires, and the heating unit is electrically connected to an external controller to automatically control the drying conditions. Preferably, the heating resistance wires are arranged near the middle area of ​​the heating unit, so that the temperature in the setting chamber first rises and then falls along the transport direction of the fiber felt substrate, reducing the impact on adjacent spraying chambers; preferably, the setting chamber includes an insulation layer to reduce heat exchange with the outside.

[0015] Based on the above technical solutions, the dust removal chamber, spraying chamber, and setting chamber are located close to each other to reduce the contact between the metal fiber felt substrate and the outside environment; or the spraying chamber and setting chamber are covered by a shell, the inner cavity of which is relatively independent from the external environment but communicates with the dust removal chamber, so that the conveying component transports the fiber felt through the dust removal chamber into the spraying chamber and setting chamber. Preferably, the inner cavity of the shell can achieve a cleanliness level of less than Class 1000, reducing contamination of the metal fiber felt substrate or sprayed coating. The inner cavity of the shell includes an air inlet and a dust removal filter unit to purify the flowing air.

[0016] Beneficial effects

[0017] This invention features an ingenious design, comprising a spraying chamber and a setting chamber arranged sequentially. During the process of the conveying component transporting the metal fiber felt substrate forward through the spraying chamber, the spray gun can uniformly coat a slurry containing a coating of a set particle size, resulting in good uniformity. Afterwards, preliminary setting can be performed in the setting chamber, ensuring that the coating powder in the sprayed layer is not dispersed and has a certain cohesive force. Even when multiple sprayed layers are stacked, they maintain a stable state, facilitating subsequent sintering processes. Ultimately, a microporous layer with gradient or other forms of pore size changes is formed, effectively achieving the preparation of gradient pore sizes at room temperature. The process is simple, efficient, and low-cost, avoiding the powder oxidation problem in high-temperature spraying. Furthermore, it allows for continuous production, overcoming the low efficiency and long production cycle problems of the scraping method.

[0018] In this invention, the spray gun in the spraying chamber atomizes the slurry before spraying, resulting in better spray uniformity and reducing the uniformity of the microporous layer to about 5% of the coating thickness. It is also flexible in use; by adjusting the spray gun's speed and flow rate, it can be used to apply various coatings and meet diverse process requirements. Furthermore, the spraying chamber is under negative pressure, creating a downward airflow. This guides the slurry mixed with coating downwards to contact the metal fiber felt substrate, while reducing slurry overflow or splashing. This minimizes disturbance to the spraying area caused by overflowing or splashing slurry, allowing the slurry to fall along a predetermined path and further improving spray uniformity. In addition, the atomized spraying method has minimal physical impact on the substrate and the already formed coating, resulting in stable and uniform thickness growth. A water curtain is also installed in the spraying chamber, preventing slurry from splashing onto the side walls and affecting subsequent spraying operations, and facilitating the recycling of slurry splashed to the sides, reducing waste.

[0019] In this invention, the heating resistance wires in the setting chamber are concentrated in the middle area of ​​the setting chamber. This allows the temperature in the setting chamber to rise first and then fall along the transport direction of the fiber felt substrate. On the one hand, this allows the sprayed coating to gradually set, resulting in a good setting effect. On the other hand, it reduces the impact on adjacent spraying chambers. After drying, the coating in the sprayed coating has adhesion, and the formed pore structure is stable, preventing collapse and other issues from occurring.

[0020] In this invention, the spraying chamber and the setting chamber are close to each other or are covered by a shell, which reduces contact with the external environment, reduces pollution, and helps improve the quality of the finished metal fiber felt microporous layer. In this invention, multiple sets of forming modules formed by the spraying chamber and the setting chamber are arranged side-by-side along the forming channel. After forming one sprayed layer, drying and setting are performed, thus forming multiple sprayed layers. This results in a stable, non-collapsed multi-layered structure, providing conditions for forming a larger thickness of microporous layer and exhibiting good adaptability. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only one embodiment of this utility model. For those skilled in the art, other embodiments can be derived from the provided drawings without creative effort.

[0022] Figure 1 Example 1: A schematic diagram of the structure of this utility model;

[0023] Figure 2 : A structural schematic diagram of the elevation view of the spray booth in Example 1;

[0024] Figure 3 : A schematic diagram of the top view of the molding chamber in Example 1;

[0025] Figure 4 : A schematic diagram of the microporous layer prepared by the preparation system in Example 1;

[0026] Figure 5 Example 2: A schematic diagram of the structure of this utility model; Detailed Implementation

[0027] The following description and accompanying drawings fully illustrate specific embodiments described herein to enable those skilled in the art to practice them. Some embodiments may include or substitute parts and features of other embodiments. The scope of the embodiments herein encompasses the entire scope of the claims and all available equivalents thereof. Throughout this document, the terms “first,” “second,” etc., are used only to distinguish one element from another without requiring or implying any actual relationship or order between the elements. Indeed, a first element can also be referred to as a second element, and vice versa. Furthermore, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a structure, apparatus, or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a structure, apparatus, or device. Without further limitation, an element defined by the phrase “comprising one…” does not exclude the presence of other identical elements in the structure, apparatus, or device that includes said element. The various embodiments described herein are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments; similar or identical parts between embodiments can be referred to interchangeably.

[0028] The terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" used in this document to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings. They are used solely for the convenience of describing the document and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description herein, unless otherwise specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two elements; they can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0029] In this document, unless otherwise stated, the term "multiple" means two or more.

[0030] In this article, the character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0031] In this article, the term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0032] Example 1

[0033] like Figure 1 The system shown is a preparation system for a metal fiber felt microporous layer for PEM electrolysis to produce hydrogen, including a conveying component 4, a dust removal chamber 1, a spraying chamber 2 and a shaping chamber 3.

[0034] In the prior art, the conveying assembly 4 in this application includes a conveyor belt and a conveying drive. The conveying drive includes a conveying motor, a conveying drive wheel, a conveying driven wheel, and multiple tensioning wheels. The conveyor belt is fitted over the conveying drive wheel and the conveying driven wheel. The conveying motor can transmit rotational motion to the conveying drive wheel, and the metal fiber felt, as the substrate, is conveyed forward by the conveyor belt. In other embodiments of this application, the conveying assembly 4 includes multiple length segments connected end to end. These multiple length segments correspond to the dust removal chamber 1, the spraying chamber 2, and the setting chamber 3, respectively. The multiple length segments can be driven by different motors to precisely control the speed at which the metal fiber felt substrate is conveyed forward along the forming channel, so as to match the different speed requirements of the substrate conveyed forward in the spraying chamber 2 or the setting chamber 3.

[0035] The inner cavities of the dust removal chamber 1, the spraying chamber 2, and the shaping chamber 3 are connected to form a forming channel through which the conveying component 4 passes. The conveying component 4 transports the fiber felt through the dust removal chamber 1 and then into the spraying chamber 2 and the shaping chamber 3.

[0036] Dust removal chamber 1 is existing technology. It filters air containing dust or other particles through airflow, and the filtered clean air is then discharged back into the environment. In this embodiment, dust removal chamber 1 is designed to achieve a cleanliness level below Class 1000. In other embodiments of this utility model, the cleanliness level of dust removal chamber 11 can be slightly lower or higher to reduce the contact between external dust or particles and the metal fiber felt substrate. In this embodiment, dust removal chamber 1 includes a dust removal fan, a dust removal air inlet, a dust removal air outlet, and a dust removal filter unit. The dust removal air inlet is located at the top of dust removal chamber 1, and the dust removal air outlet is located at the bottom of dust removal chamber 1. The dust removal fan is located at the dust removal air inlet. The dust removal filter unit is existing technology, and those skilled in the art can select it according to their needs. Under the action of the dust removal fan, the airflow introduced through the dust removal air inlet is filtered by the dust removal filter unit and then discharged. This not only creates a purified circulating airflow in dust removal chamber 1, but also blows away dust or other particles on the fiber felt substrate to achieve a dust removal effect, facilitating the subsequent application of the coating-mixed slurry onto the substrate.

[0037] like Figure 2As shown, the spraying chamber 2 includes several spray guns 5. The slurry mixed with paint is atomized by the spray guns 5 and uniformly covers the metal fiber felt substrate to form a microporous layer. In this embodiment, the paint is a metal powder, such as titanium, stainless steel, nickel, copper powder, etc., and the solvent is water. The metal powder and water are mixed to form a slurry. In other embodiments of this application, other metal powders or non-metal powders can also be used as the paint, and the solvent can be appropriately selected. This is prior art and will not be described in detail. In this embodiment, the spraying area formed by the nozzle of the spray gun 5 spans the width of the conveyor belt, so as to ensure that the metal fiber felt substrate can be completely sprayed.

[0038] Several spray guns 5 are divided into multiple groups, arranged one after the other along the axial direction of the forming channel, to spray and form a coating layer of a set thickness or to create multiple overlapping coating layers. In this embodiment, the inner diameter of the nozzle of the spray gun 5 is 1~3mm to facilitate the smooth spraying of various metal particles of different sizes. Specifically, when multiple groups of spray guns 5 spray coatings of the same particle size, the inner diameter of the nozzles of different groups of spray guns 5 remains consistent, and the conveyor belt simultaneously conveys the metal fiber felt substrate forward, which can form a coating layer of a set thickness and better ensure the uniformity of the spraying. When multiple groups of spray guns 5 spray coatings of different particle sizes, the different groups of spray guns 5 can be matched with different inner diameters of the nozzle.

[0039] Multiple spray guns 5 operate simultaneously, gradually forming sprayed layers of different thicknesses with set parameters, resulting in better spray uniformity and improved pore size uniformity in the microporous layer. When multiple spray guns 5 spray coatings of different particle sizes, sprayed layers with different pore sizes can be formed. In this embodiment, the metal fiber felt uses titanium fiber felt with a surface pore size of 30 μm as the substrate. The spray guns 5 are divided into three groups. The first group of spray guns 5, near the dust removal chamber, sprays a slurry mixed with titanium powder coating of 50 μm particle size, forming a 0.1 mm thick bottom layer. The second group of spray guns 5, in the middle, sprays a slurry mixed with titanium powder coating of 30 μm particle size, forming a 0.1 mm thick intermediate layer. The third group of spray guns 5, near the setting chamber 3, sprays a slurry mixed with titanium powder coating of 10 μm particle size, forming a 0.1 mm thick top layer. This results in a gradient pore size variation in the subsequently formed microporous layer. Figure 4 As shown. In other embodiments of this utility model, two or more layers of coatings with different particle sizes can be set, and the thickness of the coating layer for each particle size is 0.01-2 mm. The particle size variation of the coatings in multiple coating layers can also be flexibly adjusted.

[0040] In this embodiment, the spray guns 5 are positioned vertically and at an adjustable angle within the spray chamber 2. Specifically, each set of spray guns 5 is connected to a telescopic rod 6. By adjusting the telescopic rod 6, the distance between the spray gun 5 and the conveyor belt can be adjusted to accommodate the spraying of coatings with various particle sizes. Furthermore, the head of the spray gun 5 is connected upwards via a joint (not shown), which allows adjustment of the spraying direction of the spray gun 5, thus making its use more flexible. The joint is existing technology and will not be described in detail here.

[0041] The inlet of spray gun 5 is connected to a diaphragm pump via a pipeline, and the slurry mixed with paint is supplied to spray gun 5 via the diaphragm pump. This pipeline is equipped with an adjustment unit for regulating the spraying speed and flow rate of the slurry from spray gun 5. This adjustment unit is existing technology, and those skilled in the art can select it according to their needs; further details are omitted here.

[0042] like Figure 2 As shown, a negative pressure environment is formed inside the spray chamber 2 to prevent the slurry mixed with paint from overflowing. In this embodiment, the top of the spray chamber 2 is provided with several fan-shaped air nozzles, so that the airflow formed inside the spray chamber 2 flows from top to bottom to form a negative pressure environment. On the one hand, this guides the slurry mixed with paint downward to contact the metal fiber felt substrate, and on the other hand, it reduces the overflow or splashing of the slurry. This reduces the disturbance of the spraying area by the overflowing or splashing slurry, which is conducive to the slurry falling along the set path and improves the uniformity of spraying.

[0043] like Figure 2 As shown, the spray booth 2 is equipped with water curtains 7 located on both sides of the conveying assembly. Specifically, the top surface of the spray booth 2 has two narrow water outlet lines extending along the axis of the conveying assembly 4, slightly higher than the spray gun 5. Below the spray booth 2 are two water tanks 8 to receive the water curtains 7 and collect the mixture of slurry and water. The bottom surface of the water tanks 8 has an inclined angle, and the drain outlet of the water tanks 8 is located at a lower position to guide the collected water mixed with slurry into the water collection tank, allowing the paint to be recycled and reducing waste.

[0044] The setting chamber 3 includes a heating unit designed to dry and set the sprayed coating on the metal fiber felt. In this embodiment, the setting chamber 3 includes an insulation layer to reduce heat exchange with the outside, lower energy consumption, and minimize the impact on the spraying chamber 2. The heating unit 10 includes several heating resistance wires and is electrically connected to an external controller to automatically control drying conditions such as drying time and drying temperature. In this embodiment, the drying conditions are designed such that the temperature in the central area of ​​the setting chamber is 60 degrees Celsius, and the solvent in the slurry, which accounts for 70% by mass, is evaporated and dried to 40%, thus preventing the coating in the slurry from dispersing and ensuring it has a certain degree of cohesion. In other embodiments of the invention, the drying conditions are designed such that the solvent in the slurry is evaporated and dried to a mass ratio of 25-85%.

[0045] In this embodiment, as Figure 3As shown, the heating resistance wires are concentrated in the middle area of ​​the setting chamber 3, so that the temperature in the setting chamber rises and then falls along the transport direction of the fiber felt substrate. This allows the sprayed coating to gradually set, resulting in a good setting effect, and also reduces the impact on adjacent spraying chambers. In addition, the setting chamber 3 is also equipped with a setting fan, a setting air inlet, a setting air outlet, and a setting filter unit. The setting filter unit is located at the setting air outlet and the setting air inlet, and the setting fan is located at the setting air outlet. Under the action of the fan, a large airflow is formed in the setting chamber, which accelerates the drying process.

[0046] In this embodiment, as Figure 1 As shown, to isolate the dust removal chamber 1, spraying chamber 2, and setting chamber 3 from the external environment, the dust removal chamber 1 includes a dust removal inlet 11 and a dust removal outlet 12, which are horizontally elongated to allow the conveying component 4 to pass through; the spraying chamber 2 includes a spraying inlet 21 and a spraying outlet 22, which are horizontally elongated to accommodate the conveying component 4, thus effectively isolating the spraying chamber 2 from the external environment; the setting chamber 3 includes a setting inlet 21 and a setting outlet 22, which are horizontally elongated to allow the conveying component 4 to pass through, thus effectively isolating the setting chamber 3 from the outside environment.

[0047] In addition, the dust removal chamber 1, the spraying chamber 2 and the shaping chamber 3 are arranged in pairs and their internal cavities are connected. This can prevent them from coming into contact with the external environment during the spraying and forming process, which is conducive to improving the quality of the finished product after sintering.

[0048] Example 2

[0049] The difference between Example 2 and Example 1 is that, as Figure 5As shown, three sets of molding modules are arranged side-by-side, with the spraying chamber 2 and the setting chamber 3 spaced apart, and the molding channel runs through the three sets of molding modules. The spacing between the spraying chamber 2 and the setting chamber 3 reduces mutual interference and better matches the different processing rhythms of the two chambers. For example, when the substrate is transported between the spraying chamber 2 and the setting chamber 3, the time between the substrate entering the setting chamber 3 can be used to provide conditions for the previous substrate to dry effectively in the setting chamber 3. Along the conveying direction of the conveying component 4, three sets of forming modules are arranged sequentially. Three sets of spray guns 5 are respectively located in three spraying chambers 2. Specifically, the first set of spray guns 5 sprays a slurry mixed with titanium powder coating of 50µm particle size, spraying a 0.1mm thick base coat before entering the adjacent setting chamber 3 for drying and setting. Then, the second set of spray guns 5 sprays a slurry mixed with titanium powder coating of 30µm particle size, spraying a 0.1mm thick intermediate coat before entering the adjacent setting chamber 3 for drying and setting. Finally, the third set of spray guns 5 sprays a slurry mixed with titanium powder coating of 10µm particle size, spraying a 0.1mm thick top coat before entering the adjacent setting chamber 3 for drying and setting. This process of spraying and drying each coat layer separately results in good setting effect, more stable metal fiber felt and coating structure, and facilitates subsequent sintering. Figure 4 As shown.

[0050] In this embodiment, to further reduce the contamination of the metal fiber felt substrate caused by contact with the external environment, at least the spraying chamber 2 and the setting chamber 3 are covered by a shell 9. The inner cavity of the shell 9 is relatively independent from the external environment but connected to the dust removal chamber 1. The conveying assembly 4 transports the fiber felt through the dust removal chamber 1 and then into the spraying chamber 2 and the setting chamber 3. In this embodiment, the inner cavity of the shell 9 can achieve a cleanliness level of less than Class 1000, reducing contamination to the metal fiber felt substrate or the sprayed coating. The inner cavity of the shell 9 includes a shell fan, a shell air inlet, and a shell filter unit to purify the flowing air. Specifically, the shell air inlet is located at the top of the shell, the shell fan is located at the shell air inlet, and the shell filter unit is existing technology, which can be selected by those skilled in the art according to their needs. The shell filter unit is located at the shell air inlet. Under the action of the shell fan, the airflow introduced through the shell air inlet flows through the shell filter unit and is discharged, forming a purified circulating airflow within the shell.

[0051] The present invention has been described above by way of example, but the present invention is not limited to the specific embodiments described above. Any modifications or variations made based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A system for preparing a microporous metal fiber felt layer for PEM water electrolysis to produce hydrogen, characterized in that, It includes a spraying chamber (2) and a shaping chamber (3). The spraying chamber (2) and the shaping chamber (3) are connected to form a forming channel through which the conveying component (4) passes. The conveying component (4) is used to transport the fiber felt along the forming channel. The spraying chamber (2) includes several spray guns (5). The slurry mixed with paint is atomized by the spray guns (5) and uniformly covers the metal fiber felt substrate to form a microporous layer. The shaping chamber (5) includes a heating unit (10). The heating unit (10) is designed to dry the sprayed layer on the fiber felt to form a microporous layer for shaping.

2. The preparation system for the metal fiber felt microporous layer for PEM electrolysis of water to produce hydrogen according to claim 1, characterized in that, Several spray guns (5) are arranged axially along the forming channel in the spraying chamber (2) to spray and form a sprayed layer of a set thickness or to form multiple sprayed layers stacked together.

3. The preparation system for the metal fiber felt microporous layer for PEM electrolysis of water to produce hydrogen according to claim 2, characterized in that, The spray gun (5) is positioned in the spraying chamber (2) with adjustable vertical position and angle, and the spray gun (5) includes an adjustment unit for adjusting the spraying speed and flow rate of the slurry.

4. The preparation system for the metal fiber felt microporous layer for PEM electrolysis of water to produce hydrogen according to claim 3, characterized in that, The slurry mixed with paint is supplied to the spray gun (5) via a diaphragm pump.

5. The preparation system for the metal fiber felt microporous layer for PEM electrolysis of water to produce hydrogen according to claim 1, characterized in that, The spraying chamber (2) and the shaping chamber (3) form multiple sets of molding modules arranged in parallel, and the molding channel runs through multiple sets of molding modules.

6. The preparation system for the metal fiber felt microporous layer for PEM electrolysis of water to produce hydrogen according to any one of claims 1 to 5, characterized in that, It also includes a dust removal chamber (1), the forming channel extends through the dust removal chamber (1), and the conveying assembly (4) transports the fiber felt through the dust removal chamber (1) into the spraying chamber (2) and the shaping chamber (3).

7. The preparation system for the metal fiber felt microporous layer for PEM electrolysis of water to produce hydrogen according to claim 6, characterized in that, A negative pressure environment is formed inside the spraying chamber (2) to prevent the slurry mixed with paint from overflowing.

8. The preparation system for the metal fiber felt microporous layer for PEM electrolysis of water to produce hydrogen according to claim 7, characterized in that, The spraying chamber (2) is equipped with water curtains (7) located on both sides of the conveying assembly (4), and two water tanks (8) are provided below the spraying chamber (2) to receive the water curtains (7) and collect the slurry.

9. The preparation system for the metal fiber felt microporous layer for PEM electrolysis of water to produce hydrogen according to claim 6, characterized in that, The heating unit (10) includes several heating resistance wires, and the heating unit (10) is electrically connected to an external controller to automatically control the drying conditions.

10. The system for preparing a metal fiber felt microporous layer for PEM electrolysis of water to produce hydrogen according to any one of claims 7 to 9, characterized in that, The dust removal chamber (1), spraying chamber (2) and shaping chamber (3) are close to each other to reduce the contact between the metal fiber felt substrate and the outside world; or the spraying chamber (2) and shaping chamber (3) are covered with a shell (9), the inner cavity of the shell (9) is relatively independent from the outside environment and connected to the dust removal chamber (1), so that the conveying component (4) transports the fiber felt through the dust removal chamber (1) and then into the spraying chamber (2) and shaping chamber (3).

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