Method for thermal spraying pretreatment of lignin to produce hydrogen catalyst and treatment device thereof

Abstract

The application discloses a kind of hydrogen production catalysts of thermal spraying pretreatment lignin and its processing device, belong to biomass energy conversion production technical field;To solve the problem of existing hydrogen production reaction conversion rate is not ideal, the present application designs new processing device for pretreatment lignin hydrogen production catalyst, mainly including cyclone 1 and thermal spraying machine 2, the processing device can make lignin do cyclone motion in cyclone under the driving of external high-pressure gas, increase the turbulent degree of lignin in cyclone, let the surface of lignin fully contact with atomized hydrogen production catalyst small droplet, and make small droplet adhere to its surface;The present application uses thermal spraying technology coupling cyclone field structure, hydrogen production catalyst solid powder is heated to molten state by thermal spraying technology, and cyclone is designed to make lignin flow in cyclone, so that atomized hydrogen production catalyst is uniformly sprayed on the surface of lignin, so as to realize the improvement of hydrogen production reaction conversion rate.

Description

Technical Field

[0001] This invention belongs to the field of biomass energy conversion and production technology, specifically relating to a method and apparatus for thermal spraying pretreatment of lignin-based hydrogen production catalysts. Background Technology

[0002] The world today faces increasingly prominent energy shortages and environmental pollution problems, making the development and use of renewable resources to replace traditional fossil fuels an urgent priority. Biomass is a widely available and inexpensive renewable energy source, and new technologies using it as a raw material to produce fuels and fine chemicals have attracted widespread attention worldwide. Lignin, as an important component of lignocellulosic biomass, is a major byproduct of the ethanol production industry and the pulp and paper industry. Due to the stability resulting from its highly random polymer structure, the full utilization of lignin presents significant challenges.

[0003] Lignin is an aromatic polymer with a three-dimensional structure, containing numerous phenylpropanol structural units (including p-hydroxyphenylpropanol, guaiacol, eugenol, etc.). Similar to the gasification of other biomass species, the final decomposition products of lignin are a mixture of gaseous molecules such as H2, CO, CO2, and CH4, collectively known as syngas. Syngas has been proven useful for industrial applications in power generation, pure hydrogen production, synthesis of liquid fuels, and chemicals. The specific proportions of its components depend on the reaction temperature and pressure, the presence of steam and oxygen, the heating rate, and the choice of catalyst. The ratio of methane to hydrogen in the lignin-to-hydrogen reaction mixture can be selectively controlled through catalyst selection.

[0004] Hydrogen is an environmentally friendly energy source with high energy density and its combustion product is only water, causing no pollution to the environment. With the increasing depletion of traditional fossil fuels and tightening controls on carbon emissions, hydrogen energy is expected to become one of the main energy drivers of global economic development within decades. Therefore, research on the application of lignin in hydrogen production technology has significant practical importance and enormous application potential. The production of combustible gas from lignin can be achieved through three different methods: (i) conventional hydrogen production using oxygen or water vapor at high temperatures and near atmospheric pressure; (ii) pyrolysis gas release in the absence of reactive agents (i.e., air or steam); and (iii) catalytic hydrogen production in supercritical water at moderate temperatures and high pressures. An ideal hydrogen production catalyst from lignin should exhibit the following properties: high activity in opening the phenolic ring and subsequently breaking the C-C bond; high activity in the water-gas shift reaction and low activity in breaking the CO bond; and reasonable hydrothermal stability.

[0005] Traditional lignin catalytic gasification involves physically mixing lignin with a hydrogen production catalyst and then passing the mixture into a fluidized bed reactor. Inhomogeneous mixing results in only a portion of the reactants making sufficient contact with the hydrogen production catalyst, leading to a low hydrogen production rate. To address this, nickel-magnesium alloy catalysts are typically nano-sized to improve the contact efficiency between the catalyst and lignin. However, nano-sized catalysts are easily lost during the fluidized bed reaction. Pre-treating the nickel-magnesium alloy catalyst in a tubular bomb reactor, converting it from a solid to a gas under high-temperature vacuum, and then cooling it to allow the catalyst to adhere to the lignin surface can improve the contact efficiency. However, this process involves vacuuming and pressurization, requiring significant latent heat to transform the nickel-magnesium alloy from solid to liquid and then to gas, resulting in high energy consumption and a complex process that can only be operated intermittently.

[0006] Chinese Patent CN110562916A, filed on September 25, 2019, discloses a method for hydrogen production through lignin black liquor adsorption-enhanced reforming. This method removes CO2 generated during the reforming process through adsorption, directly obtaining high-purity hydrogen in one step. However, its raw material is limited to lignin black liquor, which is a cooking liquor containing inorganic salts and large amounts of lignin, cellulose, and hemicellulose used in the pulp and paper industry. Therefore, this reforming hydrogen production method is not suitable for conventional lignin. Korean Patent KR20240008149A, filed on July 11, 2022, provides an integrated system for continuous flow lignin decomposition and low-pressure hydrogen production. This invention employs a modular microfluidic system to improve lignin decomposition efficiency and innovatively provides a continuous flow lignin decomposition system capable of continuous flow lignin decomposition processes and real-time separation and extraction. However, the decomposition unit in the continuous flow lignin decomposition system includes a fluid flow reactor, which comprises multiple modules in which microfluidic tubes are arranged and connected to each other. Therefore, the system is not only complex and cumbersome in terms of setup and structure, but also requires the control of multiple modules during use.

[0007] In summary, existing technologies for improving the contact efficiency between catalysts and lignin still suffer from problems such as easy catalyst loss, high energy consumption, and complex processes. Therefore, there is an urgent need to develop a highly efficient and energy-saving method to maximize the contact between the catalyst and lignin, and ultimately improve the conversion rate of the lignin-to-hydrogen reaction. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention innovates a method and apparatus for thermally spraying pretreatment of lignin hydrogen production catalyst. The apparatus enables lignin to swirl within a hydrocyclone under the influence of external high-pressure gas, increasing the turbulence of the lignin within the hydrocyclone. This allows the surface of the lignin to fully contact the atomized hydrogen production catalyst droplets, causing the droplets to adhere to its surface, thereby improving the hydrogen production reaction conversion rate.

[0009] The technical solution of the present invention is as follows:

[0010] One of the objectives of this invention is to provide a processing device for thermally spraying pretreatment of lignin hydrogen production catalyst, the processing device mainly including a hydrocyclone 1 and a thermal spraying machine 2;

[0011] The hydrocyclone 1 is composed of a safety valve 1-1, a support plate 1-2 and a conical shell 1-3. The safety valve 1-1 is located at the center of the top of the conical shell 1-3. The outer edge of the top is provided with an annular support plate 1-2. A lignin inlet 3 is provided on the wall of the upper part of the hydrocyclone 1. The bottom of the conical shell 1-3 is connected to the lignin outlet 4.

[0012] The thermal spraying machine 2 consists of a mixed gas inlet 2-1, a nozzle 2-2, a catalyst powder inlet 5, and a powder delivery gas inlet 6. The nozzle 2-2 is welded to the other side of the upper part of the cyclone separator 1. The mixed gas inlet 2-1 extends laterally through the upper part of the thermal spraying machine 2. The powder delivery gas inlet 6 is parallel to the mixed gas inlet 2-1, located in the middle of the thermal spraying machine 2, and connected to the nozzle 2-2. The catalyst powder inlet 5 is longitudinally arranged at the tail of the thermal spraying machine 2 and communicates upward with the powder delivery gas inlet 6.

[0013] Furthermore, the thermal spraying machine is any one of plasma metal melting spraying machine, supersonic flame metal melting spraying machine, electric arc metal melting spraying machine, or flame combustion metal melting spraying machine.

[0014] Furthermore, the conical shells 1-3 are made of N08120 alloy.

[0015] The second objective of this invention is to provide a method for pretreating lignin hydrogen production catalyst by thermal spraying. The method couples thermal spraying technology with a swirling flow field structure. The hydrogen production catalyst solid powder is heated to a molten state by thermal spraying technology, and the lignin is made to swirl within the process device. The swirling lignin surface fully contacts the atomized hydrogen production catalyst fine droplets, and the fine droplets are uniformly attached to its surface.

[0016] Furthermore, this includes the following steps:

[0017] S1. Using external high-pressure gas, lignin is transported from lignin inlet 3 into hydrocyclone 1, where it undergoes swirling motion.

[0018] S2. Under the condition that the heat source is provided by the mixed gas inlet 2-1, the hydrogen production catalyst is added to the thermal spraying machine 2 through the catalyst powder inlet 5, and high-pressure nitrogen is delivered through the powder delivery gas inlet 6.

[0019] S3. The hydrogen production catalyst is melted in the high-temperature area 2-3 formed by the heat source at nozzle 2-2 of the thermal spraying machine, and atomized into fine droplets under high pressure nitrogen gas, and evenly sprayed onto the lignin surface that is in swirling motion.

[0020] S4. The lignin after spraying flows out from lignin outlet 4 and is finally transported to the fluidized bed reactor for hydrogen production reaction.

[0021] Furthermore, the external high-pressure gas in S1 is nitrogen, and the gas velocity is 10-20 m / s.

[0022] Furthermore, when the thermal spraying machine in S2 is a flame-fired metal melting spraying machine, acetylene-oxygen mixture is used as the heat source;

[0023] When the thermal spraying machine is a plasma metal melting spraying machine, the plasma spray gun generates a plasma flame as the heat source.

[0024] When the thermal spraying machine is a supersonic flame metal melting spraying machine, it uses a combustible mixture formed by supersonic ejected oxygen and fuel as a heat source. The fuel can be any one of propylene, propane, hydrogen or natural gas.

[0025] When the thermal spraying machine is an arc metal melting spraying machine, the high-temperature area formed by spark discharge generated by high-speed electron beam bombarding air and electrode materials is used as the heat source.

[0026] Furthermore, the mass ratio of lignin to hydrogen production catalyst is 100:1 to 2.

[0027] Furthermore, the hydrogen production catalyst in S2 is any one of a nickel-magnesium alloy, a copper-nickel alloy, or a combination of a nickel-magnesium alloy and nickel chloride.

[0028] Furthermore, the temperature of the molten metal inside the thermal spraying machine 2 in S2 is 450–1100°C.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] 1. This invention is the first to innovate a pretreatment device for lignin-based hydrogen production catalysts, which couples thermal spraying technology with a swirling flow field structure. The thermal spraying technology rapidly melts the catalyst, avoiding the problems of high energy consumption, complex processing procedures, and intermittent operation of traditional tubular reactors. Furthermore, the device enables lignin to swirl within a hydrocyclone under the influence of external high-pressure gas, increasing the turbulence of the lignin within the hydrocyclone. This allows each surface of the lignin to fully contact the atomized hydrogen production catalyst droplets, and for the droplets to adhere to its surface, thereby improving the hydrogen production reaction conversion rate. Compared with traditional industrial methods, this invention effectively improves the contact efficiency between the catalyst and lignin, as well as the hydrogen production reaction conversion rate.

[0031] 2. This invention couples thermal spraying technology with a swirling flow field structure. The hydrogen production catalyst solid powder is heated to a molten state using thermal spraying, and a swirling flow device is designed to cause lignin to swirl within it. This allows the atomized catalyst to be uniformly sprayed onto the lignin surface, effectively improving the contact efficiency between the hydrogen production catalyst and lignin. This solves the problem of unsatisfactory reaction conversion rate caused by low contact efficiency between the hydrogen production catalyst and lignin, and significantly improves the catalytic efficiency of lignin in the hydrogen production reaction. Under the conditions of a reaction temperature of 350℃, lignin mixed with 5wt% NaOH, and a nitrogen flow rate of 10m / s, 1000g of lignin sprayed using this invention undergoes a hydrogen production reaction in a fluidized bed, achieving a final gas yield of 59.1%, of which the hydrogen yield is 11.8% and the methane yield is 5.4%.

[0032] 3. The present invention provides a method and apparatus for pretreating lignin hydrogen production catalyst by thermal spraying. By thermally spraying lignin onto the surface of the hydrogen production catalyst, additional adhesion is generated between the two and the catalyst is utilized. This overcomes the problems of easy catalyst loss and high energy consumption in traditional lignin hydrogen production reactions, effectively reducing the energy consumption of the hydrogen production reaction process. It is not only environmentally friendly, but also simplifies the processing flow and allows for continuous operation. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the thermal spraying pretreatment lignin hydrogen production catalyst treatment device according to the present invention;

[0034] Wherein, 1-cyclone separator; 1-1-safety valve; 1-2-support plate; 1-3-conical shell; 2-thermal sprayer; 2-1-mixed gas inlet; 2-2-nozzle; 2-3-ring combustion flame; 3-lignin inlet; 4-lignin outlet; 5-catalyst powder inlet; 6-powder delivery gas inlet. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in more detail below with reference to the appendix and specific embodiments. However, the scope of protection of this invention is not limited to these embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0036] In the quantitative experiments in the following examples, three replicate experiments were set up, and the average value of the results was taken.

[0037] Unless otherwise specified, the experimental methods described in the following examples are conventional methods.

[0038] Example 1

[0039] See appendix Figure 1 This embodiment provides a processing device for thermally spraying pretreatment of lignin hydrogen production catalyst, the processing device mainly including a hydrocyclone 1 and a thermal spraying machine 2.

[0040] Traditional lignin catalytic gasification involves physically mixing lignin and catalyst before feeding them into a fluidized bed reactor. This uneven mixing results in insufficient contact between some reactants and the catalyst, leading to a low hydrogen production rate. Furthermore, it suffers from problems such as easy catalyst loss, high energy consumption, and complex processes. Therefore, in this embodiment, the hydrocyclone 1 consists of a safety valve 1-1, a support plate 1-2, and a conical shell 1-3. After the lignin is transported into the hydrocyclone through external high-pressure gas, it can undergo swirling motion within the hydrocyclone, increasing the turbulence of the lignin and ensuring that the lignin surface fully contacts the atomized catalyst droplets.

[0041] The safety valve 1-1 is located at the center of the top of the conical shell 1-3, and an annular support plate 1-2 is provided on the outer edge below the top. The safety valve 1-1 can control the device pressure to not exceed 20MPa, thus protecting personal safety and ensuring the normal operation of the equipment.

[0042] The upper side wall of the hydrocyclone 1 is provided with a lignin inlet 3, and the bottom of the conical shell 1-3 is connected to the lignin outlet 4. The sprayed lignin flows out from the lignin outlet 4 and is directly transported to the fluidized bed reactor for hydrogen production reaction.

[0043] The thermal spraying machine 2 consists of a mixed gas inlet 2-1, a nozzle 2-2, a catalyst powder inlet 5, and a powder feeding gas inlet 6. The nozzle 2-2 is welded to the other side of the upper part of the hydrocyclone 1. The mixed gas inlet 2-1 extends laterally through the upper part of the thermal spraying machine 2. The powder feeding gas inlet 6 is parallel to the mixed gas inlet 2-1, located in the middle of the thermal spraying machine 2, and connected to the nozzle 2-2. The catalyst powder inlet 5 is longitudinally arranged at the tail of the thermal spraying machine 2 and communicates upward with the powder feeding gas inlet 6. The thermal spraying machine 2 forms an annular combustion flame at the nozzle, which melts the hydrogen production catalyst under the combustion flame and atomizes it into fine droplets under the action of high-pressure nitrogen, thereby improving the contact efficiency between the hydrogen production catalyst and lignin.

[0044] The thermal spraying machine is any one of plasma metal melting spraying machine, supersonic flame metal melting spraying machine, electric arc metal melting spraying machine, or flame combustion metal melting spraying machine. The above-mentioned thermal spraying machines are simple and convenient, and the process is relatively flexible. They can be widely used for metal and alloy powders.

[0045] The conical shells 1-3 are made of N08120 alloy, which is a solid solution strengthened heat-resistant alloy and has excellent strength at high temperatures.

[0046] The working principle and usage process of this invention are as follows:

[0047] In practical use, lignin enters hydrocyclone 1 from lignin inlet 3 under the influence of high-pressure gas, and undergoes swirling motion in hydrocyclone 1; copper-nickel alloy catalyst is added to thermal sprayer 2 through catalyst powder inlet 5. Taking a supersonic flame metal melting sprayer as an example, propylene-oxygen mixture enters from mixed gas inlet 2-1 as a heat source, and high-pressure nitrogen enters from powder delivery gas inlet 6; the copper-nickel alloy catalyst melts at nozzle 2-2 of the supersonic flame metal melting sprayer, and is atomized into fine droplets under the action of high-pressure nitrogen and sprayed onto the surface of lignin. The sprayed lignin flows out from lignin outlet 4 and is transported to a fluidized bed reactor, where a hydrogen production reaction takes place.

[0048] Example 2

[0049] This embodiment provides a method for pretreating lignin-based hydrogen production catalysts with thermal spraying, including the following steps:

[0050] S1. Using nitrogen gas, 1000g of lignin is transported from lignin inlet 3 into hydrocyclone 1, where it undergoes swirling motion. The nitrogen gas flow rate is 10m / s.

[0051] S2. Under the condition that the mixed gas inlet 2-1 provides heat source, 20g of nickel-magnesium alloy catalyst is added to the flame combustion metal melting spraying machine through the catalyst powder inlet 5, and high-pressure nitrogen is delivered through the powder delivery gas inlet 6.

[0052] S3. An annular combustion flame 2-3 is formed by introducing an acetylene-oxygen mixture as a heat source through nozzle 2-2 of the flame-burning metal melting spraying machine to melt the nickel-magnesium alloy catalyst. The temperature of the molten metal in the flame-burning metal melting spraying machine is 750℃. Under the action of high-pressure nitrogen, the nickel-magnesium alloy catalyst is atomized into fine droplets and uniformly sprayed onto the lignin surface that is in swirling motion.

[0053] S4. The lignin after spraying flows out from lignin outlet 4 and is finally transported to the fluidized bed reactor for hydrogen production reaction.

[0054] Example 3

[0055] This embodiment provides a method for pretreating lignin-based hydrogen production catalysts with thermal spraying, including the following steps:

[0056] S1. Using nitrogen gas, 1000g of lignin is transported from lignin inlet 3 into hydrocyclone 1, where it undergoes swirling motion. The nitrogen gas flow rate is 20m / s.

[0057] S2. Under the condition that the mixed gas inlet 2-1 provides heat source, 10g of nickel-magnesium alloy and nickel chloride composition is added to the plasma metal melting spraying machine through catalyst powder inlet 5, while high-pressure nitrogen is delivered through powder delivery gas inlet 6.

[0058] S3. The plasma flame generated by the plasma spray gun (also known as the plasma arc generator) through the nozzle 2-2 of the plasma metal melting spray machine melts the nickel-magnesium alloy and nickel chloride composition. The temperature of the molten metal in the plasma metal melting spray machine is 450℃. Under the action of high-pressure nitrogen, the nickel-magnesium alloy and nickel chloride composition are atomized into fine droplets and uniformly sprayed onto the lignin surface that is in swirling motion.

[0059] S4. The lignin after spraying flows out from lignin outlet 4 and is finally transported to the fluidized bed reactor for hydrogen production reaction.

[0060] Depending on the actual implementation, an electric arc metal melting spraying machine can also be selected, which uses the high-temperature area formed by the spark discharge generated by the high-speed electron beam bombarding the air and electrode materials as the heat source. The temperature of the molten metal in the thermal spraying machine is adjusted between 450 and 1100°C.

[0061] Performance testing

[0062] The lignin pretreated by the thermal spraying method in Example 2 was transported to a fluidized bed reactor for hydrogen production reaction. The reaction temperature was 350°C, the nitrogen flow rate was 10 m / s, and 5 wt% NaOH was mixed in the lignin.

[0063] A control group was set up, in which 1000g of lignin and 20g of nickel-magnesium alloy catalyst were directly added into a fluidized bed reactor for hydrogen production reaction. The reaction temperature was 350℃, the nitrogen flow rate was 10m / s, and 5wt% NaOH was mixed in the lignin.

[0064] Test results: Example 2 had a final gas yield of 59.1%, with a hydrogen yield of 11.8% and a methane yield of 5.4%; the control group had a final gas yield of 44.1%, with a hydrogen yield of 6.7% and a methane yield of 3.1%.

[0065] The test results show that the method and apparatus for thermal spraying pretreatment of lignin hydrogen production catalyst provided by the present invention can effectively improve the contact efficiency between the catalyst and lignin and the conversion rate of its hydrogen production reaction.

[0066] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A thermal spray pretreated lignin hydrogen production catalyst processing apparatus, characterized by, The processing device mainly includes a hydrocyclone (1) and a thermal spraying machine (2); The hydrocyclone (1) consists of a safety valve (1-1), a support plate (1-2), and a conical shell (1-3). The safety valve (1-1) is located at the center of the top of the conical shell (1-3), and an annular support plate (1-2) is provided on the outer edge below the top. A lignin inlet (3) is provided on the wall of the upper part of the hydrocyclone (1), and the bottom of the conical shell (1-3) is connected to the lignin outlet (4). The thermal spraying machine (2) consists of a mixed gas inlet (2-1), a nozzle (2-2), a catalyst powder inlet (5), and a powder delivery gas inlet (6); the nozzle (2-2) is welded to the other side of the upper part of the cyclone separator (1); the mixed gas inlet (2-1) extends laterally through the upper part of the thermal spraying machine (2); the powder delivery gas inlet (6) is parallel to the mixed gas inlet (2-1), located in the middle of the thermal spraying machine (2), and connected to the nozzle (2-2); the catalyst powder inlet (5) is longitudinally arranged at the tail of the thermal spraying machine (2) and communicates upward with the powder delivery gas inlet (6).

2. The treatment device for hydrogen production catalyst pretreated by thermal spraying of lignin according to claim 1, characterized in that, The thermal spraying machine (2) is any one of plasma metal melting spraying machine, supersonic flame metal melting spraying machine, electric arc metal melting spraying machine or flame combustion metal melting spraying machine.

3. The treatment device for preparing a hydrogen catalyst by thermal spraying of a pretreated lignin according to claim 1, characterized in that, The conical shell (1-3) is made of N08120 alloy.

4. A method for preparing hydrogen catalyst by thermal spraying pretreated lignin using the processing device according to any one of claims 1-3, characterized in that, The method couples thermal spraying technology with a swirling field structure. The solid powder of the hydrogen production catalyst is heated to a molten state by thermal spraying technology, and the lignin is made to swirl within it using the processing device. The lignin surface undergoing swirling motion fully contacts the atomized hydrogen production catalyst droplets, and the droplets are uniformly attached to its surface.

5. The method of claim 4, wherein the thermally sprayed pretreated lignin hydrogen catalyst is characterized by: Includes the following steps: S1. Using external high-pressure gas, lignin is transported from the lignin inlet (3) into the hydrocyclone (1) and swirled in the hydrocyclone (1); S2. Under the condition that the heat source is provided by the mixed gas inlet (2-1), the hydrogen production catalyst is added to the thermal spraying machine (2) through the catalyst powder inlet (5), and high-pressure nitrogen is delivered through the powder delivery gas inlet (6). S3. The hydrogen production catalyst is melted in the high-temperature area (2-3) formed by the heat source at the nozzle (2-2) of the thermal spraying machine (2), and atomized into fine droplets under the action of high-pressure nitrogen, and uniformly sprayed onto the lignin surface that is in swirling motion. S4. The lignin after spraying flows out from the lignin outlet (4) and is finally transported to the fluidized bed reactor for hydrogen production reaction.

6. The method of claim 5, wherein the thermally sprayed pretreated lignin hydrogen catalyst is characterized by: The external high-pressure gas in S1 is nitrogen, and the gas velocity is 10-20 m / s.

7. The method of claim 5, wherein the thermal spray pretreated lignin hydrogen catalyst is characterized by: When the thermal spraying machine in S2 is a flame combustion metal melting spraying machine, acetylene-oxygen mixture is used as the heat source. When the thermal spraying machine is a plasma metal melting spraying machine, the plasma spray gun generates a plasma flame as the heat source. When the thermal spraying machine is a supersonic flame metal melting spraying machine, it uses a combustible mixture formed by supersonic ejected oxygen and fuel as a heat source. The fuel can be any one of propylene, propane, hydrogen or natural gas. When the thermal spraying machine is an arc metal melting spraying machine, the high-temperature area formed by spark discharge generated by high-speed electron beam bombarding air and electrode materials is used as the heat source.

8. The method for thermally spraying pretreatment of lignin-based hydrogen production catalyst according to claim 5, characterized in that, The mass ratio of lignin to hydrogen production catalyst is 100:1 to 2.

9. The method for thermally spraying pretreatment of lignin-based hydrogen production catalyst according to claim 5, characterized in that, The hydrogen production catalyst in S2 is any one of nickel-magnesium alloy, copper-nickel alloy, or a combination of nickel-magnesium alloy and nickel chloride.

10. The method for thermally spraying pretreated lignin-based hydrogen production catalyst according to claim 5, characterized in that, The temperature of the molten metal in the thermal spraying machine (2) in S2 is 450-1100℃.

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