High-temperature heat treatment equipment and methods for mass production of catalysts for fuel cells / water electrolyzers

Abstract

This invention provides a high-temperature heat treatment device and method for the mass production of catalysts for fuel cell water electrolyzers. The tubular furnace has a feed pipe at its inlet end, and multiple atomizing nozzles communicating with the feed pipe are located inside the furnace. An inner lining forming the heat treatment zone within the furnace is provided inside, with a storage compartment between the lining and the furnace body. The lining has multiple micropores communicating with the storage compartment. A discharge pipe is sealed and fixed at the end of the furnace body away from the feed pipe, communicating with the storage compartment. The atomizing nozzles penetrate the lining and communicate with the heat treatment zone. Multiple air guide pipes penetrating the furnace body and the lining are located at the bottom of the furnace. This invention rapidly dries the atomized powder at high temperature, and then utilizes the presence of morphological airflow combined with ultrasonic oscillation to effectively prevent the catalyst from re-agglomerating during the mass heat treatment process, thereby achieving mass and continuous heat treatment and avoiding undesirable phenomena such as insufficient catalyst heat treatment during the heat treatment stage.

Description

Technical Field

[0001] This invention relates to the field of fuel cell / water electrolyzer technology, and more particularly to a high-temperature heat treatment equipment and method for mass production of fuel cell / water electrolyzer catalysts. Background Technology

[0002] Proton exchange membrane fuel cells / water electrolyzers, as energy conversion devices, possess advantages such as low operating temperature, fast start-up, high specific power, simple structure, and environmental friendliness, and have broad application prospects in electric vehicles, portable power supplies, and stationary power stations. However, the industrialization of proton exchange membrane fuel cells / water electrolyzers is still constrained by cost and durability, and the precious metal catalyst materials used are one of the main reasons for the high cost and poor stability of fuel cells / water electrolyzers.

[0003] After the platinum-carbon catalyst for fuel cells / water electrolyzers is prepared, it needs to undergo a heat treatment process to obtain catalyst powder. During this process, the reaction temperature, heating time, and stirring method have a significant impact on the particle size and crystallinity of the platinum-carbon catalyst, while the size and distribution of platinum nanoparticles are key to determining the catalyst performance. However, most existing heat treatment methods for platinum-carbon catalysts involve drying in a reactor. During reactor drying, the catalyst in batches is placed statically inside the tank, which can lead to insufficient drying and catalyst agglomeration. The conventional approach is to increase the drying temperature, but this can cause the structure of the catalyst on the periphery of the pile to be damaged by the high temperature. Therefore, the platinum-carbon catalyst prepared by the existing heat treatment method has low yield, poor batch stability, serious waste, and high energy consumption.

[0004] On the other hand, when using a reactor for heat treatment, it is impossible to achieve continuous operation of batch catalysts. It is necessary to put some catalysts into the tank for heating, then cool them down and take them out, and then put some catalysts in again for heating. This repeated heating and cooling process will waste energy, time and manpower, and places more stringent requirements on the reactor's ability to withstand sudden temperature changes, making it difficult to achieve mass production.

[0005] In addition, carbon black or residual platinum-carbon catalysts are easily adsorbed inside the reactor and on the surface of its components, making them difficult to clean and causing blockage of the channels. Furthermore, the slurry will separate in the pipeline, resulting in poor consistency and hindering continuous production in the same period.

[0006] In addition, during the high-temperature treatment stage of the catalyst, the lattice recombination of the platinum metal in the catalyst also determines the catalytic performance of the catalyst. For small batches of catalysts, the high-temperature treatment stage in the past was carried out in the laboratory using a high-temperature tube furnace. The high-temperature tube furnace is similar to a reaction vessel and is also a furnace body with temperature control function. Even in the heat treatment process of small batches of catalysts, there are still some untreated catalysts that have not been heat treated, or even those that have clumped together.

[0007] Therefore, it is necessary to provide a new type of heat treatment equipment to solve the problems of severe agglomeration of the prepared catalyst, the presence of solvent inside the agglomerates that has not been completely dried, the inability to reorganize the catalyst inside the agglomerates through high temperature, resulting in waste of catalyst materials and poor performance. Summary of the Invention

[0008] To address the aforementioned technical problems of catalyst agglomeration, incomplete drying, low yield, and energy waste during catalyst preparation, this invention provides a high-temperature heat treatment device and method for the mass production of fuel cell / water electrolyzer catalysts. This invention primarily utilizes the rapid drying of atomized powder at high temperature, followed by the use of morphological airflow combined with ultrasonic oscillation. This effectively prevents the catalyst from re-agglomerating during the batch heat treatment process, allowing it to remain suspended within the furnace. This ensures sufficient heat treatment of the batch catalysts within the furnace. Furthermore, the combination of these two methods effectively reduces the accumulation of powder / particles on the furnace wall, minimizing waste. This achieves continuous heat treatment of the batch catalysts and avoids undesirable phenomena such as insufficient heat treatment during the heat treatment stage.

[0009] The technical means employed in this invention are as follows:

[0010] A high-temperature heat treatment device for mass production of fuel cell / water electrolyzer catalysts includes a tubular furnace, the tubular furnace including a furnace body, a feed pipe at the feed end of the furnace body, and a plurality of atomizing nozzles communicating with the feed pipe inside the furnace body;

[0011] The furnace body is coaxially provided with an inner lining layer, which constitutes the heat treatment area inside the furnace body. A material storage partition is provided between the inner lining layer and the furnace body. The inner lining layer is provided with a plurality of micropores arranged in a circular array that communicate with the material storage partition. A discharge pipe is sealed and fixed at the end of the furnace body away from the material conveying pipe. The discharge pipe communicates with the material storage partition. The atomizing nozzle penetrates the inner lining layer and communicates with the heat treatment area.

[0012] The tubular furnace is equipped with an ultrasonic oscillator.

[0013] The bottom array of the furnace body is provided with multiple gas guide pipes that penetrate the furnace body and the inner lining.

[0014] The aforementioned design of a storage compartment within the tubular furnace enables the simultaneous and continuous operation of the two processes: heat treatment of catalyst powder and its subsequent extraction and storage.

[0015] The present invention is further configured such that: the gas guide pipe is connected to an air compressor, and the air compressor delivers high-temperature gas into the furnace body.

[0016] The present invention is further configured such that: there are no fewer than two ultrasonic oscillators, all of which are disposed within the storage compartment.

[0017] The present invention is further configured such that: the inner lining layer is made of stainless steel, and the pore size of the micropores is 50-100μm.

[0018] The invention is further configured such that: the end of the conveying pipe furthest from the furnace body is connected to a storage tank; the outlet of the storage tank is equipped with a switch valve; the end of the discharge pipe furthest from the storage compartment is connected to a finished product tank; and a pump is installed between the discharge pipe and the finished product tank. Discharge is achieved through vacuum extraction, allowing the processed catalyst powder to be continuously produced from the furnace chamber without opening the furnace, thus realizing continuous production.

[0019] This invention also discloses a high-temperature heat treatment method for the mass production of catalysts for fuel cells / water electrolyzers, using the aforementioned high-temperature heat treatment equipment. The treatment method includes the following steps:

[0020] Step 1: Prepare the catalyst solution and place it in the storage tank;

[0021] Step 2: Turn on the material pump, air compressor, and ultrasonic oscillator to start the tube furnace with empty material.

[0022] Step 3: Open the atomizing nozzle, switch valve, and tubular furnace heating system to atomize the catalyst solution in the storage tank and spray it into the heat treatment area. Before the catalyst solution undergoes heat treatment, turn on all electrical components to allow the tubular furnace to operate empty for a period of time. This can effectively remove various impurities accumulated in the tubular furnace and improve the purity of the subsequent catalyst.

[0023] Step 4: The sprayed atomized catalyst solution is rapidly heated to powder form by the high temperature inside the tubular furnace and the high temperature airflow in the gas guide pipe, thus completing the heat treatment process. At the same time, it is suspended in the furnace body under the action of the airflow in the gas guide pipe and the vibration of the ultrasonic oscillator.

[0024] Step 5: Under the action of the pump, the catalyst powder that has completed the heat treatment process is drawn into the storage compartment and then enters the finished product tank through the storage compartment and the discharge pipe for storage.

[0025] The present invention is further configured such that the gas introduced by the air compressor in steps two and three is a mixture of hydrogen and argon, wherein the volume percentage of hydrogen is 5% and the volume percentage of argon is 95%.

[0026] The present invention is further configured such that the tube furnace in step two operates with empty material for 5-10 minutes.

[0027] The present invention is further configured such that the heating temperature of the tubular furnace body in step three is 400-800℃.

[0028] The present invention is further configured such that: the flow rate at the atomizing nozzle in step three is 1-10 mL / min; the gas flow rate of the air compressor is 10-50 L / s; and the oscillation frequency of the ultrasonic oscillator is 50-100 kHz.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] 1. The heat treatment equipment of this invention first uses an atomizing nozzle to spray the catalyst solution into the furnace body in an atomized form, ensuring that the catalyst solution is dispersed in small particles within the furnace body. The high-temperature system inside the tubular furnace is used to achieve rapid heating for heat treatment of the catalyst solution. During this process, the gas introduced by the air compressor simultaneously forms a high-temperature continuous airflow within the furnace body, which fully contacts the catalyst. The orderly airflow can also quickly discharge the liquid from the furnace body, further accelerating the heat treatment process. On the other hand, the presence of the morphological airflow, combined with the use of ultrasonic oscillation, can effectively prevent the catalyst from re-agglomerating during the heat treatment process in batches. That is, it can be in a floating and suspended state within the furnace body, ensuring that the batch of catalyst is fully heat-treated within the furnace body. Furthermore, the combination of these two methods can also effectively reduce the accumulation of powder / particles on the furnace body wall, reducing waste. Finally, under the action of the pump, the heat-treated catalyst powder is drawn through the micropores and enters the finished product tank for storage through the storage compartment and discharge pipe.

[0031] 2. The heat treatment equipment of the present invention adopts a vacuum extraction method for material discharge, which enables the processed catalyst powder to be produced continuously from the furnace cavity without opening the furnace cavity, thus realizing continuous production; in addition, the present invention is equipped with an external storage tank, which can realize real-time continuous feeding, and the feeding is atomized, which will not cause blockage in the furnace body or incomplete drying due to excessive material entering at one time.

[0032] 3. The present invention designs a storage compartment in the tube furnace to achieve the simultaneity and continuity of the two processes of catalyst powder heat treatment and the subsequent extraction and storage. The structure is simple, the control is convenient, and it is suitable for the heat treatment of large batches of catalysts.

[0033] 4. The present invention designs ultrasonic oscillators inside the storage compartment, and there are at least two of them, which can ensure that they act on the inner wall of the furnace body and the inner lining wall at the same time, reducing the accumulation of catalyst powder on either inner wall.

[0034] 5. Before the catalyst solution undergoes heat treatment, all electrical components are turned on to allow the tube furnace to operate with empty material for a period of time. This effectively removes various impurities accumulated in the tube furnace and improves the purity of the subsequent catalyst.

[0035] 6. The tube furnace is filled with a mixture of hydrogen and argon gas. In addition to achieving the above functions, it also allows the active metal components in the catalyst to undergo lattice recombination, which enables them to better catalyze the reaction. Furthermore, the controlled hydrogen content in this process is not dangerous.

[0036] 7. In step two of this invention, the gas flow rate of the air compressor is less than that of the air compressor in step three. This can reduce gas source waste while achieving airflow circulation and ventilation in the furnace. In step two, the vibration frequency of the ultrasonic oscillator is higher than that of the ultrasonic oscillator in step three. This can achieve the cleaning of impurities and dust in the furnace through a larger frequency vibration in a short time.

[0037] 8. The novel tubular furnace designed in this invention, combined with the functional design of the tubular furnace, provides a completely new processing technology and parameters to effectively solve the problems such as insufficient heat treatment during the batch catalyst heat treatment process.

[0038] In summary, this invention aims to achieve continuous heat treatment of catalysts in batches and avoid undesirable phenomena such as insufficient heat treatment of catalysts during the heat treatment stage. Based on the above reasons, this invention can be widely applied in the field of fuel cells / water electrolyzers. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the high-temperature heat treatment equipment of the present invention.

[0041] In the diagram: 1. Furnace body; 1-1. Feeding pipe; 1-2. Atomizing nozzle; 1-3. Discharge pipe; 2. Inner lining; 2-1. Micropores; 3. Heat treatment zone; 4. Storage compartment; 5. Ultrasonic oscillator; 6. Air compressor; 6-1. Air guide pipe; 7. Storage tank; 7-1. Switch valve; 8. Finished product tank; 8-1. Pump. Detailed Implementation

[0042] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0045] like Figure 1 As shown, the present invention provides a high-temperature heat treatment device for mass production of fuel cell / water electrolyzer catalysts, including a tubular furnace. The tubular furnace is mainly a cylindrical furnace body 1. The furnace body 1 is equipped with electrical components such as resistance wire heating sleeves to form a heating system to achieve heating of the furnace body 1.

[0046] Several atomizing nozzles 1-2 are designed inside the furnace body 1 of the tubular furnace. In this embodiment, three atomizing nozzles 1-2 are preferably set. At the same time, a storage tank 7 for storing the catalyst solution to be heat-treated is designed outside the tubular furnace. The storage tank 7 is connected to the feed end of the furnace body 1 of the tubular furnace through a conveying pipe 1-1. Specifically, the conveying pipe 1-1 is connected to each of the atomizing nozzles 1-2. A switch valve 7-1 is set at the discharge port of the storage tank 7 on the conveying pipe 1-1 to control the discharge of the storage tank 7.

[0047] The tubular furnace is equipped with a stainless steel lining 2 (using a conventional design in the art – the lining 2 is connected to the furnace body 1 via a metal connecting frame). The lining 2 is also cylindrical and coaxial with the furnace body 1. The lining 2 is hollow, and its internal space forms a heat treatment zone 3. There is an interval between the lining 2 and the furnace body 1, which is a storage compartment 4. At the same time, the lining 2 has a circumferential array of multiple micropores 2-1 that communicate with the storage compartment 4. The pore diameter of the micropores 2-1 is 50-100μm, specifically 60μm. A discharge pipe 1-3 is sealed inside the storage compartment 4 and communicates with the external finished product tank 8. The discharge pipe 1-3 is equipped with a pump 8-1 to extract the catalyst powder from the storage compartment 4 into the finished product tank 8.

[0048] This tubular furnace further includes at least two ultrasonic oscillators 5 evenly arranged within the storage compartment 4 to prevent catalyst powder accumulation on the inner wall of the furnace body 1 or the inner lining 2. Simultaneously, the bottom of the furnace body 1 is arrayed with several gas guide pipes 6-1 penetrating the furnace body 1 and the inner lining 2. The furnace body 1 is equipped with an exhaust pipe identical to the one inside (not shown in the figure). The end of each gas guide pipe 6-1 away from the furnace body 1 is connected to an external air compressor 6. The air compressor 6 is also connected to a gas source. In this invention, the gas source is a mixture of hydrogen and argon, with hydrogen accounting for 5% of the volume and argon accounting for 95%. After the air compressor 6 compresses the mixed gas, it brings the gas to a certain temperature before introducing it into the furnace body 1, thereby heating the catalyst solution and venting gas from the furnace body 1.

[0049] The present invention also discloses a method for high-temperature heat treatment using the above-mentioned equipment: Step 1, the prepared catalyst solution is poured into storage tank 7 for storage.

[0050] Step two: First, turn on the material pump 8-1, air compressor 6, and ultrasonic oscillator 5 to make the tubular furnace empty for about 5 minutes. The air compressor 6 has a gas flow rate of 10L / s and the ultrasonic oscillator 5 has an oscillation frequency of 100KHz. This causes the dust and impurities accumulated in the tubular furnace to fall off and be blown out under the vibration of the ultrasonic oscillator 5.

[0051] Step 3: After completing the empty material operation, increase the gas flow rate of the air compressor 6 to 40L / s and appropriately reduce the oscillation frequency of the ultrasonic oscillator 5 to 60KHz. Then, turn on the tube furnace heating system to raise the temperature inside the tube furnace to 500℃. Open the switch valve 7-1 at the atomizing nozzle and the storage tank 7 to allow the catalyst solution in the storage tank 7 to enter each atomizing nozzle 1-2 through the conveying pipe 1-1. The atomized catalyst solution is sprayed into the heat treatment zone 3 by the atomizing nozzle 1-2 at a flow rate of 5mL / min.

[0052] Step four: The atomized catalyst solution is rapidly heated under the high temperature inside the tube furnace and the airflow through the gas pipe 6-1. The solvent evaporates and is discharged through the exhaust pipe, forming catalyst powder, thus completing the heat treatment process.

[0053] Step 5: Then, under the action of airflow through the gas pipe 6-1 and the action of ultrasonic oscillator 5, the catalyst powder is suspended in the furnace body 1. Under the action of the pump 8-1, the catalyst powder that has completed the heat treatment process is drawn into each processing layer and enters the finished product tank 8 through the storage partition 4 and the discharge pipe 1-3 for storage.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-temperature heat treatment device for mass production of fuel cell / water electrolyzer catalysts, comprising a tubular furnace, wherein the tubular furnace includes a furnace body (1), and the feed end of the furnace body (1) is provided with a feed pipe (1-1), characterized in that: The furnace body (1) is equipped with multiple atomizing nozzles (1-2) that communicate with the material conveying pipe (1-1). The furnace body (1) is provided with an inner lining (2) coaxially, and the inner lining (2) constitutes the heat treatment area (3) inside the furnace body (1). A storage partition (4) is provided between the inner lining (2) and the furnace body (1). The inner lining (2) is provided with a plurality of micropores (2-1) that communicate with the storage partition (4) in a circular array. The furnace body (1) is sealed and fixed at one end away from the conveying pipe (1-1) with a discharge pipe (1-3). The discharge pipe (1-3) communicates with the storage partition (4). The atomizing nozzle (1-2) penetrates the inner lining (2) and communicates with the heat treatment area (3). The tubular furnace is equipped with an ultrasonic oscillator (5). The bottom array of the furnace body (1) is provided with multiple gas guide pipes (6-1) that penetrate the furnace body (1) and the inner lining layer (2). The gas guide pipe (6-1) is connected to the air compressor (6), and the air compressor (6) delivers high-temperature gas into the furnace body (1); The end of the conveying pipe (1-1) away from the furnace body (1) is connected to the storage tank (7). There is a switch valve (7-1) at the outlet of the storage tank (7). The end of the discharge pipe (1-3) away from the storage partition (4) is connected to the finished product tank (8). A pump (8-1) is provided between the discharge pipe (1-3) and the finished product tank (8).

2. The high-temperature heat treatment equipment for mass production of fuel cell / water electrolyzer catalysts according to claim 1, characterized in that: There are at least two ultrasonic oscillators (5), all of which are installed in the storage compartment (4).

3. The high-temperature heat treatment equipment for mass production of fuel cell / water electrolyzer catalysts according to claim 1, characterized in that: The inner lining (2) is made of stainless steel, and the pore size of the micropores (2-1) is 50-100μm.

4. A high-temperature heat treatment method for mass production of catalysts for fuel cells / water electrolyzers, characterized in that: Using the high-temperature heat treatment equipment according to any one of claims 1-3, the treatment method includes the following steps: Step 1: Prepare the catalyst solution and place it in the storage tank (7); Step 2: Turn on the material pump (8-1), air compressor (6), and ultrasonic oscillator (5) to make the tubular furnace empty. Step 3: The pump (8-1), air compressor (6), and ultrasonic oscillator (5) continue to work, and the atomizing nozzle, switch valve (7-1), and tubular furnace heating system are opened so that the catalyst solution in the storage tank (7) is sprayed out in an atomized form from the atomizing nozzle into the heat treatment area (3); Step 4: The sprayed atomized catalyst solution is rapidly heated to powder form by the high temperature inside the tubular furnace and the high temperature airflow from the gas pipe (6-1), thus completing the heat treatment process. At the same time, it is suspended in the furnace body (1) under the action of the airflow from the gas pipe (6-1) and the oscillation of the ultrasonic oscillator (5). Step 5: Under the action of the pump (8-1), the catalyst powder that has completed the heat treatment process is pumped to the storage compartment (4) and then enters the finished product tank (8) along the storage compartment (4) and the discharge pipe (1-3) for storage.

5. The high-temperature heat treatment method for mass production of fuel cell / water electrolyzer catalyst according to claim 4, characterized in that: In steps two and three, the air compressor (6) introduces a mixture of hydrogen and argon, with hydrogen accounting for 5% of the volume and argon accounting for 95% of the volume.

6. The high-temperature heat treatment method for mass production of fuel cell / water electrolyzer catalyst according to claim 4, characterized in that: In step two, the tubular furnace is empty for 5-10 minutes, and in step three, the heating temperature of the tubular furnace body (1) is 400-800℃.

7. The high-temperature heat treatment method for mass production of fuel cell / water electrolyzer catalyst according to claim 4, characterized in that: In step three, the flow rate at the atomizing nozzle (1-2) is 1-10 mL / min; the gas flow rate of the air compressor (6) is 10-50 L / s; and the oscillation frequency of the ultrasonic oscillator (5) is 50-100 KHz.

8. The high-temperature heat treatment method for mass production of fuel cell / water electrolyzer catalyst according to claim 4, characterized in that: In step two, the gas flow rate of the air compressor (6) is less than that of the air compressor (6) in step three, and the vibration frequency of the ultrasonic oscillator (5) in step two is higher than that of the ultrasonic oscillator (5) in step three.

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