Method for preparing biogas dry reforming carbon-based catalyst by utilizing biogas residue pyrolysis biochar, biogas dry reforming carbon-based catalyst and application thereof

Abstract

The invention discloses a method for preparing a biogas dry reforming carbon-based catalyst by utilizing biogas residue pyrolysis biochar, a biogas dry reforming carbon-based catalyst and an application thereof. The preparation method comprises: 1) drying, crushing and screening anaerobic biogas residue from kitchen waste to obtain pretreated biogas residue; 2) mixing the pretreated biogas residue with an aqueous solution of an activator, impregnating the mixture, filtering and drying the mixture to obtain modified biogas residue; 3) pyrolyzing the modified biogas residue at a temperature of 500°C-800°C in an N2 atmosphere to obtain a biogas residue biochar matrix; 4) dissolving the biogas residue biochar matrix in anhydrous ethanol to form a colloidal solution, magnetically stirring the colloidal solution at a temperature of 30°C-60°C, adding an alcohol solution of a metal salt for impregnation, and continuously stirring until the solvent is completely volatilized to obtain catalyst powder; and 5) calcining the catalyst powder at a temperature of 700°C-900°C in an N2 atmosphere, pressing the catalyst powder into tablets, crushing the catalyst powder and screening the catalyst to obtain a biogas dry reforming carbon-based catalyst. In this way, the utilization rate of biogas residue can be improved, which is beneficial to reducing the preparation cost of the catalyst.

Description

Technical Field

[0001] The present invention relates to the technical field of resource utilization of biogas residue left after anaerobic fermentation of kitchen waste and high-value utilization of biogas, and specifically to a method for preparing a biogas dry reforming carbon-based catalyst by utilizing biochar from biogas residue pyrolysis, a biogas dry reforming carbon-based catalyst and its application. Background Art

[0002] In my country, kitchen waste is mostly treated using anaerobic processes, which produces large amounts of biogas residue that is difficult to dispose of. Currently, methods for disposing of biogas residue include landfill, incineration, composting, and land use. Improper disposal or indiscriminate discharge of biogas residue can cause severe eutrophication of water bodies and affect crop growth.

[0003] Therefore, the current biogas residue treatment methods still need to be improved. Summary of the Invention

[0004] The present invention is based on the inventor's discovery and understanding of the following facts and problems:

[0005] Biogas is a gas produced during the anaerobic fermentation of organic waste, such as food waste and kitchen waste. Its main components are CH4 and CO2. Biogas can be utilized primarily for power generation and cogeneration. Currently, second-generation resource-based technologies are developing that use biogas as a raw material to produce gaseous products through a catalytic process. Among these technologies, biogas dry reforming is a promising new technology that can simultaneously convert CH4 and CO2 into synthesis gas, facilitating the conversion of biogas into high-value-added downstream chemical products. Current dry reforming catalysts are primarily composed of active metals and a matrix. Commonly used commercial matrices, such as Al2O3, SiO2, MgO, and ZrO2, consume large amounts of organic templates during production and typically use relatively expensive surfactants, which increases the cost of catalyst preparation.

[0006] The main components of the sludge left after anaerobic fermentation of kitchen waste are undecomposed organic solids and newly formed microorganisms. It is rich in organic matter, humic acid, nitrogen, phosphorus and potassium. Among them, organic matter accounts for 30% to 50%, humic acid accounts for 10% to 20%, total nitrogen accounts for 0.8% to 2.0%, total phosphorus accounts for 0.4% to 1.2%, and total potassium accounts for 0.6% to 2.0%. The composition and properties of sludge vary with different raw materials.

[0007] Biochar prepared from pyrolysis of biogas residue has the advantages of large specific surface area, developed porous structure, strong stability, and rich oxygen-containing functional groups. It can be used for the adsorption of pollutants such as ammonia nitrogen and phosphorus in sewage and for the catalytic degradation of dyes. Biochar prepared from anaerobic biogas residue is rich in alkali / alkaline earth metals and oxygen-containing functional groups and has a high specific surface area. If biochar from the pyrolysis of biogas residue can be used as a matrix to synthesize a carbon-based catalyst for biogas dry reforming, then it is possible to expand the utilization of biogas residue while reducing the preparation cost of the catalyst, which is conducive to the large-scale application of biogas dry reforming technology. At present, there is no literature disclosing such technology at home and abroad.

[0008] In view of this, the present invention aims to alleviate or solve at least one of the above-mentioned problems to at least some extent.

[0009] In one aspect of the present invention, the present invention proposes a method for preparing a biogas dry reforming carbon-based catalyst by utilizing biogas residue pyrolysis biochar. In some embodiments of the present invention, the method for preparing a biogas dry reforming carbon-based catalyst by utilizing biogas residue pyrolysis biochar comprises the following steps: 1) drying the anaerobic biogas residue from kitchen waste, crushing and screening the dried biogas residue to obtain pretreated biogas residue; 2) mixing the pretreated biogas residue with an aqueous solution of an activator, impregnating the mixture, filtering and drying the mixture to obtain modified biogas residue; 3) pyrolyzing the modified biogas residue obtained in step 2) at a temperature of 500°C-800°C and in an N2 atmosphere to obtain a biogas residue biochar-based catalyst. 4) dissolving the biochar matrix in anhydrous ethanol to form a colloidal solution, magnetically stirring the colloidal solution at 30°C-60°C, adding a metal salt alcohol solution dropwise for impregnation during the stirring process, and continuing stirring until the solvent is completely evaporated to obtain a catalyst powder; 5) calcining the catalyst powder at 700°C-900°C in an N2 atmosphere, and then using a tablet press to press the calcined powder into tablets, crush it, and sieve it to obtain a biogas dry reforming carbon-based catalyst. Using anaerobic biogas residue as a matrix to prepare the catalyst can improve the utilization rate of the biogas residue; using the treated biogas residue as the catalyst matrix for biogas dry reforming can help reduce the catalyst preparation cost, thereby facilitating the large-scale utilization of biogas dry reforming technology.

[0010] In some embodiments of the present invention, in step 4), the mass of the metal element in the alcoholic solution of the metal salt added is a, the mass of the biogas residue biochar matrix in the colloidal solution is b, and the value of a / (a+b) is 5%-20%. This helps improve the catalytic efficiency of the catalyst.

[0011] In some embodiments of the present invention, the metal salt includes at least one of Ni nitrate, Fe nitrate, Co nitrate, Rh nitrate and Pd nitrate; and / or, in the alcohol solution of the metal salt, the solvent includes at least one of ethanol, n-propanol, isopropanol, n-butanol and isobutanol.

[0012] In some embodiments of the present invention, the metal salt comprises two of Ni nitrate, Fe nitrate, Co nitrate, Rh nitrate, and Pd nitrate, and the molar ratio of the two metal elements in the alcohol solution of the metal salt is 1:3-3:1. Thus, the prepared catalyst contains two metals, and the different metal elements complement each other, which is more conducive to improving the catalytic efficiency of the catalyst.

[0013] In some embodiments of the present invention, the activator includes at least one of KOH, ZnCl2, MgCl2, CaCl2, and FeCl3. Such activators can improve the acidity and alkalinity and / or site activity of the biogas residue biochar matrix, at least to a certain extent, thereby improving the catalytic efficiency of the catalyst.

[0014] In some embodiments of the present invention, in step 1), the anaerobic digestate from kitchen waste is dried at 80°C-95°C for 12-24 hours; and / or, in step 1), the digestate is sieved using a 20-100 mesh sieve. Pretreatment using the above conditions can produce dry digestate with relatively uniform particles.

[0015] In some embodiments of the present invention, in step 2), the mass ratio of the pretreated biogas residue to the activating agent is 1:1-1:2.5; and / or the immersion time in step 2) is 24-48 hours. This facilitates sufficient contact between the activating agent and the biogas residue, thereby improving the performance of the substrate.

[0016] In some embodiments of the present invention, the method for preparing a biogas dry reforming carbon-based catalyst satisfies at least one of the following conditions: in step 3), the pyrolysis time is 1-3 hours; in step 4), the speed of magnetic stirring is 400r / min-800r / min; in step 5), the calcination time is 3-6 hours; the particle size of the biogas dry reforming carbon-based catalyst is 20 mesh-100 mesh.

[0017] In another aspect, the present invention provides a biogas dry reforming carbon-based catalyst. In some embodiments of the present invention, the biogas dry reforming carbon-based catalyst is prepared using the method described above. As a result, the biogas dry reforming carbon-based catalyst has high catalytic activity and can catalyze the biogas dry reforming reaction, converting CH4 and CO2 in the biogas into synthesis gas, thereby promoting the conversion of biogas into high-value-added downstream chemical products.

[0018] In another aspect, the present invention provides the use of the aforementioned biogas dry reforming carbon-based catalyst in biogas dry reforming. The aforementioned biogas dry reforming carbon-based catalyst can be used in the biogas dry reforming process to provide a good catalytic effect. Furthermore, the carbon-based catalyst has a low preparation cost, facilitating the large-scale application of biogas dry reforming technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0020] Figure 1 A flow chart of a method for preparing a biogas dry reforming carbon-based catalyst by pyrolyzing biochar from biogas residue according to one embodiment of the present invention is shown. DETAILED DESCRIPTION

[0021] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0022] In one aspect of the present invention, a method for preparing a biogas dry reforming carbon-based catalyst by pyrolyzing biochar from biogas residue is proposed. Figure 1 The method for preparing a biogas dry reforming carbon-based catalyst by pyrolyzing biochar from biogas residue may include the following steps:

[0023] 1) Drying the anaerobic digestate from kitchen waste, crushing and screening the dried digestate to obtain pretreated digestate.

[0024] In some embodiments of the present invention, in step 1), the anaerobic digestate from kitchen waste can be dried at 80°C-95°C for 12-24 hours. For example, the anaerobic digestate can be dried at 80°C, 85°C, 90°C, or 95°C for 12 hours, 15 hours, 18 hours, 20 hours, 24 hours, etc. Drying the anaerobic digestate under the above conditions can remove moisture and volatile impurities from the anaerobic digestate, which is beneficial for the subsequent preparation of the catalyst.

[0025] In some embodiments of the invention, the digestate may be comminuted using a plant comminutor.

[0026] In some embodiments of the present invention, in step 1), the crushed biogas residue can be screened using a 20-mesh sieve to a 100-mesh sieve. For example, the biogas residue can be screened using a 20-mesh sieve, a 40-mesh sieve, a 60-mesh sieve, or a 100-mesh sieve to obtain biogas residue with smaller particles and more uniform size, so as to facilitate the subsequent loading of the catalyst active substance (metal catalyst).

[0027] In step 1), the anaerobic digestate is pretreated to remove moisture from the anaerobic digestate, and the digestate is crushed and sieved to obtain digestate with uniform particles and smaller sizes.

[0028] 2) The pretreated biogas residue is mixed with an aqueous solution of an activator, and after immersion, the mixture is filtered and dried to obtain a modified biogas residue.

[0029] In some embodiments of the present invention, the activator may include at least one of KOH, ZnCl2, MgCl2, CaCl2, and FeCl3. In some embodiments of the present invention, the activator may be KOH, ZnCl2, MgCl2, CaCl2, or FeCl3. In other embodiments of the present invention, the activator may include two or more of KOH, ZnCl2, MgCl2, CaCl2, and FeCl3. The above-mentioned activators can improve the acidity and alkalinity of the matrix and / or the site activity, etc., which is beneficial to the subsequent loading of the catalyst active material, thereby facilitating the improvement of the catalyst activity.

[0030] In some embodiments of the present invention, in step 2), the mass ratio of pretreated biogas residue to activator can be 1:1-1:2.5. For example, the mass ratio of pretreated biogas residue to activator can be 1:1, 1:1.5, 1:2, 1:2.5, etc. Thus, the pretreated biogas residue and the activator have a suitable mass ratio, which is beneficial to sufficient contact and reaction between the activator and the pretreated biogas residue, thereby improving the acidity and alkalinity of the matrix and / or site activity, and further improving the catalytic efficiency of the catalyst.

[0031] In the present invention, there is no specific limitation on the concentration of the aqueous solution of the activator, and those skilled in the art can set and adjust the concentration of the aqueous solution of the activator according to actual needs.

[0032] In some embodiments of the present invention, the immersion time in step 2) may be 24-48 hours, for example, 24 hours, 30 hours, 36 hours, 40 hours, 48 ​​hours, etc. Longer immersion time of the pretreated biogas residue and the aqueous solution of the activator facilitates sufficient contact and reaction between the activator and the biogas residue, thereby modifying the biogas residue to impart suitable acidity and alkalinity and higher site activity.

[0033] 3) Pyrolyzing the modified biogas residue obtained in step 2) at a temperature of 500° C. to 800° C. in a N 2 atmosphere to obtain a biogas residue biochar matrix.

[0034] In some embodiments of the present invention, the modified biogas residue prepared in step 2) can be pyrolyzed at 500°C, 600°C, 650°C, 700°C, 750°C or 800°C to decompose the biogas residue to form biochar.

[0035] In some embodiments of the present invention, during the pyrolysis process, the flow rate of N2 can be 20ml / min-40ml / min. For example, the flow rate of N2 can be 20ml / min, 25ml / min, 30ml / min, 35ml / min or 40ml / min. Continuously introducing N2 at the above flow rate during the pyrolysis process is beneficial to removing water and impurities produced by the pyrolysis of sludge.

[0036] In some embodiments of the present invention, in step 3), the pyrolysis time can be 1-3 hours, for example, the pyrolysis time can be 1 hour, 1.5 hours, 2 hours, 2.5 hours or 3 hours, thereby allowing the biogas residue to be more fully pyrolyzed, removing organic matter in the biogas residue and obtaining a biochar matrix with better performance.

[0037] 4) dissolving the biogas residue biochar matrix in anhydrous ethanol to form a colloidal solution, magnetically stirring the colloidal solution at a temperature of 30° C. to 60° C., adding an alcohol solution of a metal salt dropwise during the stirring process for impregnation, and continuing to stir until the solvent is completely evaporated to obtain a catalyst powder.

[0038] In some embodiments of the present invention, the colloidal solution can be magnetically stirred at 30°C, 35°C, 40°C, 45°C, 50°C, 55°C or 60°C. Stirring at this temperature is conducive to the volatilization of the organic solvent.

[0039] In some embodiments of the present invention, in step 4), the speed of magnetic stirring can be 400 r / min-800 r / min, for example, the speed of magnetic stirring can be 400 r / min, 500 r / min, 600 r / min, 700 r / min, 800 r / min, etc. Stirring at the above speed is conducive to sufficient mixing of the colloidal solution and the alcohol solution of the metal salt, and is conducive to the volatilization of the organic solvent to obtain a mixture with uniform components.

[0040] In some embodiments of the present invention, the metal salt may include at least one of Ni nitrate, Fe nitrate, Co nitrate, Rh nitrate, and Pd nitrate. The above metal salts can form metal catalysts after calcination and be supported on the biochar matrix.

[0041] In some embodiments of the present invention, the metal salt may include two of Ni nitrate, Fe nitrate, Co nitrate, Rh nitrate and Pd nitrate, and the molar ratio of the two metal elements in the alcohol solution of the metal salt may be 1:3-3:1. In some embodiments of the present invention, the metal salt may include Ni nitrate and Fe nitrate, and the molar ratio of nickel element to iron element in the alcohol solution of the metal salt may be 1:3, 1:1, 2:1 or 3:1. In other embodiments of the present invention, the metal salt may include Ni nitrate and Co nitrate, or the metal salt may include Rh nitrate and Pd nitrate, or the metal salt may include Fe nitrate and Co nitrate.

[0042] In some embodiments of the present invention, in step 4), the mass of the metal element in the alcoholic solution of the added metal salt is a, the mass of the biogas residue biochar matrix in the colloidal solution is b, and the ratio a / (a+b) is 5%-20%. For example, the ratio a / (a+b) can be 5%, 8%, 10%, 12%, 15%, or 20%. The above ratio of raw materials, after calcination, results in a catalyst having an appropriate content of metal active material, which is beneficial for improving the catalytic efficiency of the catalyst.

[0043] In some embodiments of the present invention, the solvent in the alcoholic solution of the metal salt may include at least one of ethanol, n-propanol, isopropanol, n-butanol, and isobutanol. In some specific embodiments of the present invention, the solvent in the alcoholic solution of the metal salt may be ethanol, n-propanol, isopropanol, n-butanol, or isobutanol. In other specific embodiments of the present invention, the solvent in the alcoholic solution of the metal salt may consist of two or more of ethanol, n-propanol, isopropanol, n-butanol, and isobutanol.

[0044] 5) calcining the catalyst powder at a temperature of 700° C. to 900° C. in an N 2 atmosphere, and then using a tablet press to press the calcined powder into tablets, crushing and screening the powder to obtain a biogas dry reforming carbon-based catalyst.

[0045] In some embodiments of the present invention, the catalyst powder may be calcined at 700° C., 750° C., 800° C., 850° C., or 900° C. This allows the metal salt to decompose to form a metal catalyst that is loaded on the biochar matrix, resulting in a catalyst with good stability.

[0046] In some embodiments of the present invention, in step 5), the calcination time can be 3-6 hours, for example, the calcination time can be 3 hours, 4 hours, 5 hours or 6 hours, thereby facilitating the full reaction of the catalyst precursor and allowing the metal salt to completely react to form a metal catalyst.

[0047] In some embodiments of the present invention, the particle size of the biogas dry reforming carbon-based catalyst can be 20 mesh to 100 mesh. For example, the particle size of the biogas dry reforming carbon-based catalyst can be 20 mesh, 30 mesh, 50 mesh, or 100 mesh. In some embodiments of the present invention, in step 5), the crushed powder can be sieved using a 20-100 mesh sieve to obtain a catalyst with a suitable and uniform particle size.

[0048] In general, the preparation of biogas dry reforming catalyst using the method proposed in the present invention has the following advantages:

[0049] 1. Preparing biochar from sludge, a by-product of anaerobic fermentation of kitchen waste, and using it as a matrix to synthesize carbon-based catalysts can provide a new way to solve the problem of anaerobic sludge disposal and the high-value utilization of sludge.

[0050] 2. The catalyst produced by the method proposed in the present invention has strong catalytic activity and good stability, and is suitable for biogas dry reforming technology.

[0051] 3. Biochar prepared using biogas residue as raw material is cheaper than commercial substrates, which can reduce the synthesis cost of biogas dry reforming catalysts, facilitate the large-scale application of biogas dry reforming technology, and realize the simultaneous resource utilization of biogas residue and biogas from anaerobic fermentation of kitchen waste.

[0052] In another aspect, the present invention provides a biogas dry reforming carbon-based catalyst. In some embodiments of the present invention, the biogas dry reforming carbon-based catalyst is prepared using the aforementioned method. As a result, the catalyst exhibits excellent stability and strong catalytic activity, making it suitable for biogas dry reforming. The catalyst also has a wide range of raw material sources and a low substrate preparation cost, which helps reduce the catalyst synthesis cost.

[0053] In another aspect, the present invention provides the use of the aforementioned biogas dry reforming carbon-based catalyst in biogas dry reforming. The biogas dry reforming carbon-based catalyst exhibits excellent stability and strong catalytic activity, enabling simultaneous conversion of CH4 and CO2 into synthesis gas, promoting the high-value-added conversion of biogas into downstream chemical products.

[0054] The present invention will be described below by specific examples, and it will be appreciated by those skilled in the art that the following specific examples are merely for illustrative purposes and are not intended to limit the scope of the invention in any way. In addition, in the following examples, unless otherwise specified, the materials and equipment employed are all commercially available. If, in the following examples, specific processing conditions and treatment process are not clearly described, then conditions and methods well known in the art may be employed to process.

[0055] Example 1

[0056] Reference Figure 1 A method for preparing a biogas dry reforming carbon-based catalyst by pyrolyzing biochar from biogas residue comprises the following steps:

[0057] 1) drying the anaerobic digestate from kitchen waste at 80° C. for 12 hours, crushing it with a plant grinder, and sieving it through a 40-mesh sieve to obtain a pretreated digestate;

[0058] 2) mixing the pretreated biogas residue obtained in step 1) with an aqueous solution of an activator ZnCl2, wherein the mass ratio of the pretreated biogas residue to ZnCl2 is 1:1, soaking for 24 hours, filtering and drying to obtain a modified biogas residue;

[0059] 3) pyrolyzing the modified biogas residue obtained in step 2) at 600° C. under a nitrogen atmosphere for 1 hour to obtain a biochar matrix;

[0060] 4) Dissolve 1.1151 g of Ni(NO3)2·6H2O solid and 1.6233 g of Fe(NO3)3·9H2O solid in 40 ml of anhydrous ethanol to obtain an active metal salt alcohol solution;

[0061] Dissolve 4.05 g of the biochar matrix obtained in step 3) in 50 ml of anhydrous ethanol to form a uniform colloidal solution;

[0062] The colloidal solution was magnetically stirred at 60°C and 600 r / min, and the active metal salt alcohol solution was added dropwise for impregnation. The mixture was stirred continuously until the ethanol was completely evaporated to obtain catalyst powder.

[0063] 5) The catalyst powder obtained in step 4) is placed in a tubular furnace and calcined at 700° C. in a N 2 atmosphere for 6 hours; the calcined powder is tableted using a tablet press, crushed, and sieved to obtain catalyst product particles of 20-100 mesh.

[0064] Example 2

[0065] Reference Figure 1 A method for preparing a biogas dry reforming carbon-based catalyst by pyrolyzing biochar from biogas residue comprises the following steps:

[0066] 1) drying the anaerobic digestate from kitchen waste at 80° C. for 12 hours, crushing it with a plant grinder, and sieving it through a 40-mesh sieve to obtain a pretreated digestate;

[0067] 2) mixing the pretreated biogas residue obtained in step 1) with an aqueous solution of an activator FeCl3, wherein the mass ratio of the pretreated biogas residue to FeCl3 is 1:1, soaking for 24 hours, filtering and drying to obtain a modified biogas residue;

[0068] 3) pyrolyzing the modified biogas residue obtained in step 2) at 600° C. under a nitrogen atmosphere for 1 hour to obtain a biochar matrix;

[0069] 4) Dissolve 1.1151 g of Ni(NO3)2·6H2O solid and 1.6644 g of Co(NO3)2·6H2O solid in 40 ml of anhydrous ethanol to obtain an active metal salt alcohol solution;

[0070] Dissolve 4.05 g of the biochar matrix obtained in step 3) in 50 ml of anhydrous ethanol to form a uniform colloidal solution;

[0071] The colloidal solution was magnetically stirred at 50°C and 600 r / min, and the active metal salt alcohol solution was added dropwise for impregnation. The mixture was stirred continuously until the ethanol was completely evaporated to obtain catalyst powder.

[0072] 5) The catalyst powder obtained in step 4) is placed in a tubular furnace and calcined at 700° C. in a N 2 atmosphere for 8 hours; the calcined powder is tableted using a tablet press, crushed, and sieved to obtain catalyst product particles of 20-100 mesh.

[0073] Example 3

[0074] The difference from Example 1 is that the active agent in step 2) is CaCl2, and the other steps and parameters are the same as those in Example 1.

[0075] Example 4

[0076] The difference from Example 1 is that the immersion time in step 2) is 48 hours, and the other steps and parameters are the same as those in Example 1.

[0077] Example 5

[0078] The difference from Example 1 is that in step 2), the mass ratio of pretreated biogas residue to activator ZnCl2 is 1:1.5, and the other steps and parameters are the same as those in Example 1.

[0079] Example 6

[0080] The difference from Example 2 is that the pyrolysis temperature in step 3) is 700° C., and the other steps and parameters are the same as those in Example 2.

[0081] The specific surface areas and reforming conversion rates of the carbon-based catalyst products prepared in Examples 1 to 6 are shown in Table 1.

[0082] Table 1

[0083]

[0084] As can be seen from Table 1, the specific surface area of ​​the biogas residue dry reforming carbon-based catalyst prepared by the method of the present invention can reach tens to hundreds of m 2 / g, suitable for use as a catalyst; the biogas reforming test results show that the catalyst proposed in the present invention has good catalytic activity and stability.

[0085] In the description of this specification, reference to the terms "one embodiment", "some embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment are included in at least one embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0086] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a biogas dry reforming carbon-based catalyst by pyrolyzing biochar from biogas residue, characterized in that: The following steps are involved: 1) drying the anaerobic digestate from kitchen waste, crushing and screening the dried digestate to obtain pretreated digestate; 2) mixing the pretreated biogas residue with an aqueous solution of an activator, immersing the mixture, filtering the mixture, and drying the mixture to obtain a modified biogas residue; 3) pyrolyzing the modified biogas residue obtained in step 2) at a temperature of 500° C. to 800° C. in an N 2 atmosphere to obtain a biogas residue biochar matrix; 4) dissolving the biogas residue biochar matrix in anhydrous ethanol to form a colloidal solution, magnetically stirring the colloidal solution at a temperature of 30° C. to 60° C., adding a metal salt alcohol solution dropwise for impregnation during the stirring process, and continuing to stir until the solvent is completely evaporated to obtain a catalyst powder; 5) calcining the catalyst powder at a temperature of 700° C. to 900° C. in an N 2 atmosphere, and then tableting the calcined powder using a tablet press, crushing, and screening to obtain a biogas dry reforming carbon-based catalyst.

2. The method according to claim 1, characterized in that In step 4), the mass of the metal element in the added alcohol solution of the metal salt is a, the mass of the biogas residue biochar matrix in the colloidal solution is b, and the value of a / (a+b) is 5%-20%.

3. The method according to claim 1, characterized in that The metal salt includes at least one of Ni nitrate, Fe nitrate, Co nitrate, Rh nitrate and Pd nitrate; And / or, in the alcohol solution of the metal salt, the solvent includes at least one of ethanol, n-propanol, isopropanol, n-butanol and isobutanol.

4. The method according to claim 1, wherein The metal salts include two of Ni nitrate, Fe nitrate, Co nitrate, Rh nitrate and Pd nitrate. In the alcohol solution of the metal salts, the molar ratio of the two metal elements is 1:3-3:

1.

5. The method according to claim 1, wherein The activator includes at least one of KOH, ZnCl2, MgCl2, CaCl2 and FeCl3.

6. The method according to any one of claims 1 to 5, characterized in that In step 1), the anaerobic digestate of the kitchen waste is dried at 80°C-95°C for 12-24 hours; And / or, in step 1), sieving is performed using a 20-100 mesh sieve.

7. The method according to any one of claims 1 to 5, characterized in that In step 2), the mass ratio of the pretreated biogas residue to the activator is 1:1-1:2.5; And / or, the immersion time in step 2) is 24-48 hours.

8. The method according to any one of claims 1 to 5, characterized in that At least one of the following conditions is met: In step 3), the pyrolysis time is 1-3 hours; In step 4), the speed of magnetic stirring is 400 rpm to 800 rpm; In step 5), the calcination time is 3-6 hours; The particle size of the biogas dry reforming carbon-based catalyst is 20 meshes to 100 meshes.

9. A biogas dry reforming carbon-based catalyst, characterized in that: The biogas dry reforming carbon-based catalyst is prepared by the method according to any one of claims 1 to 8.

10. Use of the biogas dry reforming carbon-based catalyst according to claim 9 in biogas dry reforming.

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