A monolithic biomass industrial catalyst, its preparation method and application

Abstract

This invention belongs to the field of methanol synthesis catalyst technology, specifically relating to an industrial catalyst for methanol synthesis, and its preparation method and application. Cordierite honeycomb ceramics are pretreated to increase their specific surface area. Al₂O₃ powder, boehmite powder, and biochar powder are mixed in a mass ratio of 1:5:1 to 1:9:4 to form biochar aluminum powder. This biochar aluminum powder is then made into biochar aluminum colloid, and copper nitrate is added to the biochar aluminum colloid to form a biochar active sol. The biochar active sol is then attached to the surface of the pretreated cordierite honeycomb ceramics, maintaining the honeycomb structure. The catalyst is then aged, shaped, and calcined to obtain the final product. The industrial catalyst prepared by this invention has advantages such as simple composition, low airflow resistance, good thermal stability, high compressive strength, and corrosion resistance, enabling high-efficiency and long-term methanol synthesis.

Description

Technical Field

[0001] This invention belongs to the field of methanol synthesis catalyst technology, and relates to industrial catalysts for methanol synthesis, specifically a biomass monolithic industrial catalyst, its preparation method, and its application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Methanol is typically produced from syngas (hydrogen, carbon monoxide, and carbon dioxide) in the presence of a catalyst. The catalyst can lower the reaction temperature and pressure, improve reaction efficiency, and enhance the selectivity of methanol as a product. According to the inventors' research, current methanol synthesis catalysts contain numerous components, such as copper, zinc, magnesium, aluminum, expensive graphite, and molecular sieves, resulting in poor economic efficiency. Furthermore, these catalysts require further processing (e.g., tableting) before industrial application. This secondary processing significantly reduces the catalyst's mechanical strength and stability. Moreover, the processed catalyst, especially in tablet form, exhibits greater resistance to gas flow, limiting its use to low space velocities (~10000 h⁻¹). -1 Methanol production at high space velocities (≥50000h) is not suitable. -1 Industrial production. Furthermore, in practical applications, industrial catalysts often suffer from uneven temperature distribution within the reaction system due to the large reaction bed, leading to localized overheating and catalyst deactivation. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a biomass monolithic industrial catalyst, its preparation method, and its application. The industrial catalyst prepared by the present invention has advantages such as simple composition, low airflow resistance, good thermal stability, high compressive strength, corrosion resistance, and easy molding. When applied to the industrial production of methanol synthesis, it can improve reaction efficiency, increase catalyst life, and thus reduce the cost of methanol synthesis.

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

[0006] On the one hand, a method for preparing a biomass monolithic industrial catalyst includes the following steps:

[0007] The cordierite honeycomb ceramic is pretreated to increase its specific surface area.

[0008] Al2O3 powder, boehmite powder and biochar powder are prepared into biochar aluminum powder in a mass ratio of 1:5:1 to 1:9:4. The biochar aluminum powder is then made into biomass aluminum gel. Then, active metal salts are added to the biomass aluminum gel to make biomass active sol.

[0009] The biomass active sol is attached to the surface of pretreated cordierite honeycomb ceramics, and the cordierite honeycomb ceramics with biomass active sol attached retain the honeycomb structure. Then, the ceramics are aged, shaped, and calcined to obtain the final product.

[0010] Cordierite honeycomb ceramic is a type of honeycomb ceramic material with the chemical composition 2MgO·2Al2O3·5SiO2. Its anisotropic crystal structure gives it "orienting" extrusion properties, an extremely low coefficient of thermal expansion, and good mechanical strength, thermal stability, and corrosion resistance. This invention uses cordierite honeycomb ceramic as the matrix for a catalyst, which has an extremely low coefficient of thermal expansion (<1.8*10). -6 / K), which can improve the thermal shock resistance of the catalyst; it has an extremely high melting point (1450℃), which can enhance the catalyst's anti-sintering performance, thus maintaining stable physicochemical properties for a long time at 1200℃; it has good axial compressive strength (≥10MPa), which can adapt to the impact environment of multi-layered catalyst stacking and high-space velocity airflow, thus effectively utilizing the space in the reaction tower and adapting to high-space velocity industrial reaction conditions; it has strong acid, alkali and corrosion resistance, which can effectively inhibit catalyst poisoning; its honeycomb structure can reduce the airflow resistance of the reaction and adapt to high-space velocity reactions (≥50000h). -1 However, cordierite honeycomb ceramics have a relatively small specific surface area (<1m²). 2 If the active component is directly loaded ( / g), the loading amount is small, the specific surface area is small, and the reaction site that the support can provide for the active component is limited.

[0011] This invention first uses Al2O3 powder and pseudoboehmite powder to prepare aluminum colloid via powder dispersion, which serves as a coating material. This coating is used to load the active components onto cordierite honeycomb ceramics, thereby improving the loading strength and catalyst stability. Secondly, this invention adds biochar powder during the aluminum colloid preparation process. Biochar powder has an extremely large surface area (1500–3500 m²). 2 The catalyst ( / g) not only better adsorbs active components and increases their loading, but also forms a three-component system with aluminum colloid and copper active component. Subsequent aging and calcination further enhance the catalyst's thermal stability. Furthermore, the pretreatment process increases its specific surface area, which is beneficial for the composite of biomass active sol and cordierite honeycomb ceramics, thereby improving the loading efficiency of active components.

[0012] On the other hand, a biomass monolithic industrial catalyst is obtained by the above preparation method.

[0013] Thirdly, the application of one of the above-mentioned biomass monolithic industrial catalysts in the catalytic synthesis of methanol from carbon monoxide, carbon dioxide, and hydrogen, wherein the methanol synthesis process has a space velocity of 20,000–100,000 h⁻¹. -1 The temperature ranges from 220 to 350℃.

[0014] Experiments have shown that the biomass monolithic industrial catalyst provided by this invention exhibits high activity in methanol synthesis under high space velocity conditions, which can greatly improve the methanol production efficiency.

[0015] The beneficial effects of this invention are as follows:

[0016] 1. The biomass monolithic industrial catalyst prepared by this invention is made from renewable powdered biomass and inexpensive cordierite, pseudothallium powder and Al2O3 powder. The raw materials are widely available, low in cost, universal, easy to industrialize, and have potential market value.

[0017] 2. The biomass monolithic industrial catalyst provided by this invention has the characteristics of low gas resistance, strong thermal stability and high compressive strength, thus it can be applied to the industrial catalytic synthesis of methanol at high reaction temperatures and high space velocities.

[0018] 3. The method for preparing the biomass monolithic industrial catalyst provided by this invention, and its application in catalyzing methanol synthesis, enables the recycling of biomass resources, thereby achieving green production. Detailed Implementation

[0019] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0020] 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.

[0021] In view of the problems of existing methanol synthesis catalysts, such as high preparation cost, poor thermal stability, low compressive strength, poor corrosion resistance and low applicable space velocity, this invention proposes a biomass monolithic industrial catalyst, its preparation method and application.

[0022] A typical embodiment of the present invention provides a method for preparing a biomass monolithic industrial catalyst, comprising the following steps:

[0023] The cordierite honeycomb ceramic is pretreated to increase its specific surface area.

[0024] Al2O3 powder, boehmite powder and biochar powder are prepared into biochar aluminum powder in a mass ratio of 1:5:1 to 1:9:4. The biochar aluminum powder is then made into biomass aluminum gel. Copper nitrate is then added to the biomass aluminum gel to prepare biomass active sol.

[0025] The biomass active sol is attached to the surface of pretreated cordierite honeycomb ceramics, and the cordierite honeycomb ceramics with biomass active sol attached retain the honeycomb structure. Then, the ceramics are aged, shaped, and calcined to obtain the final product.

[0026] Methods to increase specific surface area include sputtering, ion implantation, and chemical etching, among which chemical etching includes acid etching, alkaline etching, and oxidative etching. In some embodiments, the pretreatment includes hydrothermal pickling. The hydrothermal pickling method described in this invention is a process performed using a hydrothermal method. The hydrothermal method described in this invention involves heating water as a solvent under closed conditions to achieve a reaction system pressure higher than the ambient air pressure. Hydrothermal pickling not only increases the specific surface area but also facilitates increased pore volume, further promoting the composite formation of biomass active sol and cordierite honeycomb ceramics.

[0027] In one or more embodiments, the hydrothermal pickling temperature is 150–250°C. Under these conditions, the pickling efficiency is higher, and it is more conducive to increasing the specific surface area and pore volume of cordierite honeycomb ceramics. The hydrothermal pickling time is 1–2 hours. The acid used in the hydrothermal pickling is hydrochloric acid, sulfuric acid, nitric acid, etc. Specifically, the acid used in the hydrothermal pickling is dilute nitric acid, which refers to a nitric acid solution with a mass concentration not exceeding 20%, preferably 5–20%. Using dilute nitric acid is beneficial for subsequent removal, and nitrate ions are more conducive to matching with active metals, thereby increasing the loading efficiency of active components.

[0028] In one or more embodiments, the pretreatment includes calcining the cordierite honeycomb ceramic. Calcination removes impurities from its surface and pores. Calcination prior to hydrothermal pickling not only removes impurities from its surface and pores but also prevents impurities in the surface pores from affecting the increase in specific surface area, thereby enhancing the effect of hydrothermal pickling on improving the specific surface area of ​​the cordierite honeycomb ceramic.

[0029] Specifically, the firing temperature for removing impurities from the surface and pores of cordierite honeycomb ceramics is 300–450℃. Under these conditions, the efficiency of impurity removal is higher. The firing time is 1–2.5 hours.

[0030] In one or more embodiments, hydrothermal acid washing is followed by pretreatment calcination. Calcination after hydrothermal acid washing not only helps remove residual acid from the surface and pores of the cordierite honeycomb ceramic, but also regulates the pore structure and ensures the formulation strength of the cordierite honeycomb ceramic after acid treatment, thus facilitating the application of the prepared monolithic biomass industrial catalyst in high-space-velocity industrial applications. Specifically, in the pretreatment calcination, the programmed temperature rise is 350–500°C. More specifically, the heating rate in the pretreatment calcination is 5–10°C / min. This condition is more conducive to the recovery of the mineral phase structure.

[0031] In one or more embodiments, the hydrothermal acid pickling is followed by washing and drying. Washing removes nitric acid adhering to the surface, while drying removes moisture. Simultaneously, drying before pretreatment and calcination prevents rapid moisture evaporation during calcination from damaging the pore structure of the cordierite honeycomb ceramic. Specifically, after hydrothermal acid pickling, the surface is washed with water until neutral. The drying temperature is 80–120°C.

[0032] In some embodiments, the biomass is produced by drying, crushing, and pyrolyzing biomass, and the biomass is waste biomass, such as dead tree branches. This facilitates waste recycling and reduces costs.

[0033] In one or more embodiments, the pyrolysis temperature for preparing biochar powder is 400–600°C. This temperature is more conducive to increasing the specific surface area of ​​the biochar powder.

[0034] The process of preparing biomass aluminum gel from biochar aluminum powder according to this invention is as follows: dissolving biochar aluminum powder, adding a gelling agent to perform sol-solution to obtain biomass aluminum gel. The gelling agent can be sulfuric acid, nitric acid, or hydrochloric acid. Using dilute nitric acid as the gelling agent is more conducive to subsequent removal. The concentration of dilute nitric acid used during sol-solution is 5-10%. The pH of the biomass aluminum gel is 2-4. Generally, aluminum gel has a pH of 2, which is relatively acidic. Due to the large specific surface area and high hydrophilicity of biochar, which can increase the viscosity of the solution, it is conducive to sol formation. Therefore, the pH of the resulting biomass aluminum gel is slightly higher, 3-4 is sufficient.

[0035] The purpose of adding the active metal salt in this invention is to impart an active component to the catalyst. Active metals include copper, zinc, magnesium, etc. In some embodiments, the active metal salt is an active metal nitrate. Since the acid used in the preceding processes of this invention is nitric acid, using a nitrate allows for better matching. Specifically, the active metal salt is copper nitrate. More specifically, in the biomass active sol, the amount of copper nitrate, based on the mass percentage of CuO, is 5-25%.

[0036] The biomass active sol is attached to the surface of pretreated cordierite honeycomb ceramics, and the cordierite honeycomb ceramics with the attached biomass active sol maintain the honeycomb structure. The purpose is to ensure that the biomass active sol is completely attached to the surface and pores of the pretreated cordierite honeycomb ceramics, while maintaining the overall morphology of the cordierite honeycomb ceramics after the biomass active sol is attached. This allows the prepared catalyst to maintain the honeycomb structure, reduce gas flow resistance in the reaction, and adapt to high space velocity reactions. This can be achieved by immersing the pretreated cordierite honeycomb ceramics in the biomass active sol, ensuring complete contact, and then blowing away excess sol from the pores. Alternatively, biomass active sol can be poured into the pretreated cordierite honeycomb ceramics, ensuring complete contact between the poured biomass active sol and the pretreated cordierite honeycomb ceramics, and then blowing away or leaching away excess sol from the pores.

[0037] In some embodiments, the aging time is 8 to 16 hours.

[0038] In some embodiments, the material is aged, dried, and then shaped and calcined.

[0039] In some embodiments, during the molding calcination, the temperature is programmed to rise to 450–600°C. Specifically, the heating rate during molding calcination is 5–10°C / min. This condition is more conducive to improving the overall thermal stability of the catalyst. The molding calcination time is 2–4 hours.

[0040] The pretreatment calcination and forming calcination described in this invention are both calcination processes. The purpose of naming them separately is to distinguish between calcinations, not to limit the purpose of calcination.

[0041] Another embodiment of the present invention provides a biomass monolithic industrial catalyst, obtained by the above preparation method.

[0042] A third embodiment of the present invention provides the application of the above-mentioned biomass monolithic industrial catalyst in the catalytic synthesis of methanol from carbon monoxide, carbon dioxide, and hydrogen, wherein the space velocity during the methanol synthesis process is 20,000 to 100,000 h⁻¹. -1 The temperature ranges from 220 to 350℃.

[0043] In some embodiments, the volume ratio of carbon monoxide, carbon dioxide, and hydrogen is 5:1:13 to 8:1:25. This condition is more conducive to the complete reaction of the materials.

[0044] In some embodiments, the biomass monolithic industrial catalyst is activated at 220–300°C in a mixed atmosphere of hydrogen and nitrogen before catalysis. The activation time is preferably 2–4 hours. In the mixed atmosphere of hydrogen and nitrogen, the volume fraction of hydrogen is preferably 5–20%.

[0045] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0046] In the following examples, the generated methanol was analyzed using an Agilent 2977C gas chromatography-mass spectrometry (GC-MS) system.

[0047] Example 1

[0048] Dead tree branches were selected as raw materials, dried at 70°C to remove excess moisture, and crushed to 100 mesh to form powdered biomass pulverizer. Then, the pulverizer was placed in a flowing nitrogen atmosphere at 400°C for 2 hours to generate biochar powder.

[0049] After cleaning and drying the cordierite honeycomb ceramic with deionized water, it was calcined in a muffle furnace at 400℃ for 2 hours. The pre-treated cordierite was then immersed in a high-pressure reactor containing 10% dilute nitric acid and placed in an oven at 200℃ for 1.5 hours. The cordierite treated with dilute nitric acid was then cleaned with deionized water until neutral and dried in an oven at 100℃. The dried sample was then placed in a muffle furnace, and the temperature was raised to 400℃ with a programmed heating rate of 5℃ / min. The sample was then calcined at this temperature for 1 hour. The specific surface area and pore volume of the obtained cordierite carrier were tested using a NOVA4200e, and the compressive strength was tested using a compressive strength tester. The results are shown in Table 1.

[0050] Take 10g of Al2O3 powder, 65g of boehmite and 10g of biochar powder and mix them in a ball mill jar containing alumina grinding balls. Ball mill intermittently for 7 hours to obtain biochar aluminum powder. Place it in a beaker, add a small amount of deionized water and stir until it becomes a suspension. During stirring, add diluted nitric acid solution (10%) dropwise to dissolve the gel. Control the pH of the prepared biochar aluminum gel to be 3. Add 28.4g of Cu(NO3)2·3H2O solid to the aluminum gel and stir to dissolve it completely. Let it stand and age for 4 hours to obtain 10% CuO / biochar aluminum gel.

[0051] Acid-treated cordierite was immersed in aged 10% CuO / biomass alumina sol and stirred continuously for 0.5 hours to ensure full contact between the cordierite and the sol. After removal, excess sol in the pores was blown away with a rubber bulb, and the mixture was aged for 12 hours. It was then dried in an oven at 70°C for 1 hour, and then transferred to a muffle furnace with a programmed heating rate of 10°C / min to raise the temperature to 450°C. The mixture was then calcined at this temperature for 2 hours to obtain a 10% CuO / biomass monolithic catalyst.

[0052] 20g of biomass monolithic catalyst was loaded into the reaction chamber and reduced for 2h at 270℃ in a 5% H2 / N2 atmosphere.

[0053] Select an airspeed of 50,000 h-1 A mixture of carbon monoxide, carbon dioxide, and hydrogen with a volume fraction of 7:1:23 is introduced into the reaction chamber as a reaction raw material, and a methanol mixture containing water vapor is generated under normal pressure and a temperature of 270°C.

[0054] The generated mixed solution and unreacted mixed gas flow through a condenser. The unreacted raw materials are returned to the reaction chamber. The condensed mixed solution is distilled at 85°C and condensed again through the heat exchanger in the reaction chamber. The density of the resulting methanol solution is tested and its concentration is calculated. The results are shown in Table 2.

[0055] Table 1. Specific surface area of ​​cordierite carrier before and after acid treatment

[0056] substance Blank Iolite 10% acid treatment <![CDATA[Specific surface area (m 2 / g)]]> 0.29 144.1 <![CDATA[Pore volume (cm 3 / g)]]> 0.015 0.050 Compressive strength (MPa) 9.9 9.7

[0057] Table 2 Characterization of methanol synthesis catalyzed by CuO / biomass monolithic catalyst

[0058] substance methanol water content / % 85.48 14.52

[0059] Example 2:

[0060] Dead tree branches were selected as raw materials, dried at 80℃ to remove excess moisture, and crushed to 200 mesh to form powdered biomass pulverizer. Then, it was placed in a flowing nitrogen atmosphere at 450℃ for 2 hours to generate biochar powder.

[0061] After cleaning and drying the cordierite honeycomb ceramic with deionized water, it was calcined in a muffle furnace at 450℃ for 2 hours. The pre-treated cordierite was then immersed in a high-pressure reactor containing 15% dilute nitric acid and placed in an oven at 150℃ for 2 hours. The cordierite treated with dilute nitric acid was then cleaned with deionized water until neutral and dried in an oven at 110℃. The dried sample was then placed in a muffle furnace, and the temperature was raised to 450℃ with a programmed heating rate of 10℃ / min. The sample was then calcined at this temperature for 1 hour. The specific surface area and pore volume of the obtained cordierite carrier were tested using a NOVA 4200e instrument, and the compressive strength was tested using a compressive strength tester. The results are shown in Table 3.

[0062] 10g of Al2O3 powder, 60g of boehmite and 15g of biochar powder were mixed and placed in a ball mill jar containing alumina grinding balls. The mixture was intermittently ball milled for 8 hours to obtain biochar aluminum powder. The mixture was placed in a beaker and a small amount of deionized water was added and stirred until it reached a suspension state. During stirring, a diluted nitric acid solution (5%) was added dropwise to dissolve the mixture. The pH of the prepared biochar aluminum glue was controlled to be 4. 64.3g of Cu(NO3)2·3H2O solid was added to the aluminum glue and stirred until it was fully dissolved. The mixture was allowed to stand and age for 5 hours to obtain 20% CuO / biochar aluminum glue.

[0063] Acid-treated cordierite was immersed in aged 20% CuO / biomass alumina sol and stirred continuously for 1 hour to ensure full contact between the cordierite and the sol. After removal, excess sol in the pores was blown away with a rubber bulb, and the mixture was aged for 12 hours. It was then dried in an oven at 80°C for 2 hours, and then transferred to a muffle furnace with a programmed heating rate of 10°C / min to raise the temperature to 500°C. The mixture was then calcined at this temperature for 3 hours to obtain a 20% CuO / biomass monolithic catalyst.

[0064] 20g of biomass monolithic catalyst was loaded into the reaction chamber and reduced for 2h at 250℃ in a 9% H2 / N2 atmosphere.

[0065] Select airspeed as 100,000 h -1 A mixture of carbon monoxide, carbon dioxide, and hydrogen with a volume fraction of 7:1:23 is introduced into the reaction chamber as a reaction raw material, and a methanol mixture containing water vapor is generated under normal pressure and a temperature of 300°C.

[0066] The generated mixed solution and unreacted mixed gas flow through a condenser. The unreacted raw materials are returned to the reaction chamber. The condensed mixed solution is distilled at 90°C and condensed again through the heat exchanger in the reaction chamber. The density of the resulting methanol solution is tested and its concentration is calculated. The results are shown in Table 4.

[0067] Table 3 Specific surface area of ​​cordierite carrier before and after acid treatment

[0068]

[0069]

[0070] Table 4 Characterization of methanol synthesis catalyzed by CuO / biomass monolithic catalyst

[0071] substance methanol water content / % 93.62 6.38

[0072] As can be seen from the data in Tables 1 and 3, the specific surface area and pore volume of cordierite increased significantly after acid treatment, which is beneficial to the loading of CuO / biomass alumina gel and the stability of the catalyst. The compressive strength can still maintain a high level after acid treatment, which has a great advantage in terms of industrialization compared with the compressive strength of common methanol synthesis catalysts on the market (<1MPa).

[0073] As can be seen from the data in Tables 2 and 4, the catalyst prepared by the method of the present invention has a high space velocity (50000 h⁻¹). -1 and 100000h -1 The catalyst still exhibits high activity, indicating that it is suitable for industrial conditions with high space velocities, which greatly improves production efficiency.

[0074] The product of this invention is a high-concentration methanol solution. The condensation and reflux of the reactants in the reaction system and the utilization of heat exchange in the reaction chamber reduce the energy consumption and improve the efficiency of the reaction.

[0075] Calculations show that the cost of the industrial catalyst prepared using the materials and process of this invention is RMB 19,000 to RMB 25,000 per ton, which is more economical than commercial methanol synthesis catalysts on the market (≥ RMB 50,000 per ton).

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. The application of a biomass monolithic industrial catalyst in the catalytic synthesis of methanol from carbon monoxide, carbon dioxide, and hydrogen, characterized in that, During the synthesis of methanol, the space velocity is 20,000~100,000 h⁻¹ -1 The temperature is 220~350 ℃; The preparation method of the biomass monolithic industrial catalyst includes the following steps: The cordierite honeycomb ceramic is pretreated to increase its specific surface area. Al2O3 powder, boehmite powder and biochar powder are prepared into biochar aluminum powder in a mass ratio of 1:5:1 to 1:9:

4. The biochar aluminum powder is then made into biomass aluminum gel. Then, active metal salts are added to the biomass aluminum gel to make biomass active sol. The biomass active sol is attached to the surface of pretreated cordierite honeycomb ceramics, and the cordierite honeycomb ceramics with biomass active sol attached retain the honeycomb structure. Then, the ceramics are aged, shaped, and calcined to obtain the final product.

2. The application as described in claim 1, characterized in that, The pretreatment includes hydrothermal pickling.

3. The application as described in claim 2, characterized in that, The temperature for hydrothermal pickling is 150~250 ℃; the pickling time is 1~2 h; the acid used in hydrothermal pickling is dilute nitric acid, which refers to a nitric acid solution with a mass concentration not exceeding 20%.

4. The application as described in claim 3, characterized in that, The concentration of the dilute nitric acid is 5-20%.

5. The application as described in claim 2, characterized in that, After hydrothermal pickling, the product is washed and dried; after hydrothermal pickling, it is washed with water until neutral; the drying temperature is 80~120 ℃; then it undergoes pretreatment and calcination. During the pretreatment calcination, the temperature is programmed to rise to 350~500 ℃; the heating rate during the pretreatment calcination is 5~10 ℃ / min.

6. The application as described in claim 1, characterized in that, The pretreatment includes firing the cordierite honeycomb ceramic; The firing temperature for removing impurities from the surface and pores of cordierite honeycomb ceramics is 300~450 ℃; the firing time is 1~2.5h.

7. The application as described in claim 1, characterized in that, The biomass is produced by drying, crushing, and pyrolyzing biomass, and the biomass is waste biomass; The pyrolysis temperature for preparing biochar powder is 300~400 ℃; The active metal salt is an active metal nitrate; the active metal salt is copper nitrate; in the biomass active sol, the amount of copper nitrate, calculated as the mass percentage of CuO, is 5-25%.

8. The application as described in claim 1, characterized in that, The aging time is 8-16 hours; After aging, it is dried and then shaped and calcined. During the molding and calcination process, the temperature is programmed to rise to 450~600 ℃; the heating rate during molding and calcination is 5~10 ℃ / min; and the molding and calcination time is 2~4 h.

9. The application as described in claim 1, characterized in that, The volume ratio of carbon monoxide, carbon dioxide, and hydrogen is 5:1:13 to 8:1:

25. Before catalysis, the biomass monolithic industrial catalyst is activated by heating to 220~300℃ in a mixed atmosphere of hydrogen and nitrogen for 2~4 h; the volume fraction of hydrogen in the mixed atmosphere is 5~20%.

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