Methanation catalysts, processes for their preparation and use, and methanation processes

Abstract

This invention relates to the field of catalyst preparation, and discloses a methanation catalyst, its preparation method and application, and a methanation method. The methanation catalyst contains a catalyst support and a nickel active component. Based on the total mass of the methanation catalyst, the catalyst support comprises 80-90 wt% by mass, and the nickel active component (calculated as oxide) comprises 10-20 wt% by mass. The average mechanical strength of the catalyst support is 35-80 N / mm. The particle mechanical strength dispersion coefficient of the catalyst support is in the range of 0-0.55. The catalyst support has a large specific surface area and pore volume. Combined with the supported nickel active component, it can improve the catalytic activity and selectivity of the catalyst. Simultaneously, the catalyst has high average mechanical strength, resulting in high CO conversion and methane selectivity in the methanation reaction.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation, specifically to a methanation catalyst, its preparation method and application, and a methanation method. Background Technology

[0002] Methanation is a reaction that uses hydrogen to reduce carbon monoxide and carbon dioxide to produce methane and water. During this reaction, the activity of the catalyst has a crucial impact on the reaction rate and production capacity. Methanation reactions at medium and high temperatures present challenges such as high reaction temperatures, large heat fluxes, easy catalyst coking, and harsh hydrothermal environments. Therefore, the methanation catalysts used must not only possess high catalytic performance but also exhibit high requirements for thermal stability, hydrothermal stability, resistance to coking, and mechanical strength.

[0003] To better utilize the performance of catalysts, higher requirements are placed on the physicochemical properties of catalyst supports. Catalyst supports need to have a larger specific surface area, larger pore volume, more suitable pore size and surface properties, and higher strength. In addition, the shape of the catalyst also plays a very important role in engineering applications (heat transfer, mass transfer, pressure drop, etc.).

[0004] When using a fixed-bed reactor for methanation, certain requirements are placed on the catalyst particle size and shape to reduce pressure drop, ensuring a high porosity in the catalyst bed after loading and thus minimizing pressure drop. Extrusion molding is a highly efficient and relatively inexpensive molding method. It is relatively easy to obtain a carrier of general strength by extruding materials with small particle diameters, but obtaining a high-strength carrier by extruding larger particle diameters presents certain challenges.

[0005] Therefore, it is necessary to develop a methanation catalyst that simultaneously possesses high catalytic activity and high stability in the methanation reaction, and whose resistance to high-temperature hydrothermal environment, specific surface area, pore structure stability, and mechanical strength all meet industrial requirements. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of insufficient mechanical strength of the support for methanation catalysts in the prior art, which makes the prepared catalysts easy to break, have poor thermal stability and poor resistance to coking. The invention provides a methanation catalyst, its preparation method and application, and a methanation method. The support of this catalyst has a large specific surface area and pore volume. Combined with the supported nickel active component, it can improve the catalytic activity and selectivity of the catalyst. At the same time, the catalyst has high average mechanical strength and can achieve high CO conversion and methane selectivity when applied to the methanation reaction.

[0007] To achieve the above objectives, a first aspect of the present invention provides a methanation catalyst, wherein the methanation catalyst contains a catalyst support and a nickel active component;

[0008] The catalyst support comprises 80-90 wt% of the total mass of the methanation catalyst, and the active nickel component comprises 10-20 wt% of the total mass of the oxide.

[0009] The catalyst support has an average mechanical strength of 35-80 N / mm;

[0010] The particle mechanical strength dispersion coefficient of the catalyst support is in the range of 0-0.55.

[0011] A second aspect of the present invention provides a method for preparing a methanation catalyst, wherein the method comprises:

[0012] (1) The catalyst support is obtained by mixing the support precursor with the colloidal solvent, and then molding and calcining.

[0013] (2) The catalyst support is impregnated in a solution containing nickel compounds and then calcined to obtain a methanation catalyst;

[0014] The temperature change of the material before and after molding is less than 15°C.

[0015] The third aspect of the present invention provides a methanation catalyst prepared by the preparation method described in the second aspect.

[0016] The fourth aspect of this invention provides the application of the methanation catalyst described in the first or third aspect in a methanation reaction.

[0017] The fifth aspect of the present invention provides a methanation method in which H2 / CO feed gas is contacted with the methanation catalyst described in the first or third aspect to carry out a methanation reaction.

[0018] The beneficial effects achieved through the above technical solution are as follows:

[0019] (1) The methanation catalyst provided by the present invention has high average mechanical strength and high catalytic activity and catalytic stability in the methanation reaction;

[0020] (2) In this invention, the preparation method of the methanation catalyst is simple, which improves the mechanical strength of the catalyst support while ensuring that the catalyst support has a high specific surface area and pore volume, providing active sites for the loading and dispersion of nickel active components, thereby improving the catalytic activity of the methanation catalyst; using the methanation catalyst in the methanation reaction can ensure high CO conversion rate and high CH4 selectivity. Attached Figure Description

[0021] Figure 1 This is an appearance diagram of the butterfly-shaped extruded strip prepared in Example 1;

[0022] Figure 2 This is a schematic diagram of the mechanical strength distribution of the carrier in Examples 2, 6 and Comparative Example 3. Detailed Implementation

[0023] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0024] The first aspect of the present invention provides a methanation catalyst, wherein the methanation catalyst comprises a catalyst support and a nickel active component;

[0025] The catalyst support comprises 80-90 wt% of the total mass of the methanation catalyst, and the active nickel component comprises 10-20 wt% of the total mass of the oxide.

[0026] The catalyst support has an average mechanical strength of 35-80 N / mm;

[0027] The particle mechanical strength dispersion coefficient of the catalyst support is in the range of 0-0.55.

[0028] In this invention, the catalyst support has high mechanical strength, small dispersion coefficient, and concentrated mechanical strength distribution. The methanation catalyst prepared using the above catalyst support has strong adaptability and exhibits high CO conversion rate and methane selectivity in the methanation reaction.

[0029] In this invention, the dispersion coefficient refers to the dispersion of the mechanical strength of the catalyst support particles, which is the ratio of the standard deviation of the mechanical strength values ​​of a set of catalyst support particles to their average value. The number of catalyst support particles is n, which is 15-30, and the dispersion coefficient of the mechanical strength of the catalyst support particles is in the range of 0-0.55.

[0030] According to the present invention, preferably, the particle mechanical strength dispersion coefficient of the catalyst support is in the range of 0-0.55, for example, 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.52, 0.55, or any range between the two, preferably in the range of 0.15-0.52.

[0031] In this invention, the average mechanical strength refers to the average value calculated from the compressive strength tested on 22 catalyst support particles. The compressive strength is obtained by measuring the crushing mechanical strength.

[0032] According to the present invention, preferably, the catalyst support has a mass percentage of 81-89 wt% based on the total mass of the methanation catalyst, and the nickel active component has a mass percentage of 11-19 wt% based on oxides.

[0033] According to the present invention, the type of catalyst support is not particularly limited, as long as the specific surface area, pore volume, and average mechanical strength of the support meet the defined range. Preferably, the catalyst support is selected from at least one of alumina, silicon dioxide, zirconium oxide, titanium dioxide, magnesium oxide, calcium oxide, silicon nitride, silicon carbide, and carbon materials, and is preferably alumina.

[0034] According to the present invention, preferably, the catalyst support has an average mechanical strength of 38-75 N / mm.

[0035] According to the present invention, preferably, the specific surface area of ​​the catalyst support is 60-130 m². 2 / g, for example 60m 2 / g、70m 2 / g、80m 2 / g、90m 2 / g, 100m 2 / g、110m 2 / g、120m 2 / g、130m 2 / g, or any range between the two, preferably 70-120m 2 / g.

[0036] According to the present invention, preferably, the pore volume of the catalyst support is 0.3-0.6 mL / g, for example 0.3 mL / g, 0.35 mL / g, 0.4 mL / g, 0.45 mL / g, 0.5 mL / g, 0.55 mL / g, 0.6 mL / g, or any range between the two, preferably 0.35-0.55 mL / g. In the present invention, the specific surface area and pore volume of the catalyst support are measured by the BET low-temperature nitrogen adsorption method.

[0037] In this invention, the catalyst support has a high specific surface area and high pore volume, and the nickel active component can be uniformly dispersed in the support, while ensuring that the catalyst has high average mechanical strength.

[0038] In this invention, the particle diameter of the catalyst support is not particularly limited. Preferably, the particle diameter of the catalyst support is 3-20 mm, more preferably 3.5-15 mm. Catalyst supports with smaller particle diameters are easier to mold and achieve high mechanical strength; conversely, larger particle diameters make it more difficult to improve mechanical strength. In this invention, the catalyst support achieves high specific surface area, high pore volume, and high mechanical strength while maintaining a relatively large particle diameter.

[0039] In this invention, the particle diameter of the catalyst support is measured by measuring the diameter of the circumscribed circle of the support cross-section.

[0040] A second aspect of the present invention provides a method for preparing a methanation catalyst, wherein the method comprises:

[0041] (1) The catalyst support is obtained by mixing the support precursor with the colloidal solvent, and then molding and calcining.

[0042] (2) The catalyst support is impregnated in a solution containing nickel compounds and then calcined to obtain a methanation catalyst;

[0043] The temperature change of the material before and after molding is less than 15°C.

[0044] In this invention, the methanation catalyst preparation method is simple, has strong raw material adaptability, is environmentally friendly, and is easy to scale up industrially. The obtained methanation catalyst has high mechanical strength and exhibits high CO conversion and high methane selectivity when used in the methanation reaction.

[0045] In this invention, the catalyst support has a large specific surface area and pore volume while ensuring high mechanical strength. The preparation method is simple and stable, easy to scale up industrially, has strong raw material adaptability, and is environmentally friendly.

[0046] According to the present invention, preferably, the temperature change of the material before and after molding is less than 15°C, and more preferably less than 12°C. In this invention, controlling the temperature change of the material before and after molding minimizes the deformation of the material caused by temperature changes during the molding process, which helps to improve the average mechanical strength of the catalyst support.

[0047] According to the present invention, preferably, the molding temperature is 1-60℃, more preferably 5-50℃; the molding pressure is 3-20MPa, more preferably 4-15MPa. In the present invention, the molding temperature is controlled within a relatively low temperature range to avoid uneven heating of the outer surface and interior of the molded product particles due to molding at higher temperatures, resulting in excessively high outer surface temperature and excessively low internal temperature, which reduces the mechanical strength of the obtained catalyst support.

[0048] According to the present invention, preferably, in step (1), the mixing further includes the addition of water and a modifying agent. The modifying agent is an agent capable of modulating the physical properties of the support and increasing the alkalinity of the support. The modifying agent can be added directly to the support precursor in the form of a metal oxide, or it can be dissolved in water in the form of a metal compound and then added to the support precursor, or it can be added to the catalyst support by impregnation.

[0049] According to the present invention, preferably, the volume of water added is 0.6-1 mL, more preferably 0.65-0.95 mL, based on 1 g of the carrier precursor.

[0050] The inventors of this invention have discovered that by adding a binder and suitable modifiers during molding, combined with appropriate molding conditions, a high-strength carrier with a large specific surface area and pore volume can be obtained.

[0051] According to the present invention, preferably, the modifying agent is selected from at least one of compounds containing alkali metal elements, alkaline earth metal elements and rare earth metal elements, and more preferably from at least one of oxides, carbonates, basic carbonates, organic salts, nitrates and hydroxides of alkali metal elements, alkaline earth metal elements and rare earth metal elements.

[0052] According to the present invention, preferably, the modifying agent is selected from at least one of oxides and / or nitrates of alkaline earth metals and rare earth metals, and more preferably from at least one of lanthanum nitrate, magnesium nitrate, zinc nitrate, potassium nitrate, magnesium oxide, calcium oxide, lanthanum acetate, and magnesium acetate. In the present invention, the above-mentioned modifying agent is used in combination with the support precursor and the colloidal solvent to improve the stability of the support precursor, making the dehydroxylation and / or phase transformation of the support precursor during calcination more gradual, which helps to maintain the specific surface area and pore volume of the catalyst support without affecting its mechanical strength.

[0053] In this invention, preferably, the carrier and the modifying agent are of different types.

[0054] According to the present invention, preferably, the amount of the modifying agent added relative to 100 parts by weight of the carrier precursor is 0.6-15 parts by weight, for example, 0.6 parts by weight, 0.8 parts by weight, 1 part by weight, 1.5 parts by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 6 parts by weight, 8 parts by weight, 10 parts by weight, 12 parts by weight, 14 parts by weight, 15 parts by weight, or any range between the two, preferably 0.8-12 parts by weight. Insufficient addition of the modifying agent will not achieve the effect of modulating the physical properties of the carrier and increasing the alkalinity of the carrier; excessive addition of the modifying agent will affect the mechanical strength of the catalyst carrier and reduce the specific surface area of ​​the carrier.

[0055] According to the present invention, preferably, the carrier precursor is a substance that is converted into a carrier through subsequent calcination. In the present invention, the source of the carrier precursor is not particularly limited; those skilled in the art can choose conventional carrier precursors, which can be commercially available or prepared by existing methods, as long as they can be converted into a carrier after calcination.

[0056] In this invention, preferably, the carrier precursor is selected from at least one of alumina, metallic aluminates, silicon dioxide, aluminosilicates, silicate minerals, titanium dioxide, zirconium oxide, magnesium oxide, zinc oxide, silicon nitride, silicon carbide, and carbon materials. The alumina may be hydrated alumina and / or alumina colloid, and the aluminosilicate may be zeolite and / or kaolin.

[0057] According to the present invention, preferably, the carrier precursor is selected from at least one of boehmite, calcium oxide and magnesium oxide.

[0058] According to the present invention, preferably, the carrier is selected from at least one of alumina, silicon dioxide, zirconium oxide, titanium dioxide, magnesium oxide, calcium oxide, silicon nitride, silicon carbide, and carbon materials, and is preferably alumina.

[0059] In this invention, preferably, alumina has the characteristics of large specific surface area, controllable pore structure, good thermal stability and strong adsorption capacity. Using boehmite as a precursor to prepare the catalyst support, the resulting catalyst support has a higher specific surface area and pore volume, which is beneficial to the loading and dispersion of active components. Further preparation of the catalyst results in higher catalytic activity.

[0060] According to the present invention, the type of colloidal solvent is not particularly limited, and it can be any colloidal solvent conventionally used in the art. Preferably, the colloidal solvent is an organic acid and / or an inorganic acid, preferably selected from at least one of nitric acid, aluminum nitrate, acetic acid, and citric acid, and more preferably a mixture of nitric acid and aluminum nitrate and / or citric acid. In the present invention, the addition of a colloidal solvent enables sufficient colloidal dissolution between the precursor particles, improves the mechanical strength of the formed catalyst support, and improves the pore structure.

[0061] According to the present invention, preferably, the amount of the adhesive solvent added is 0.4-10 parts by weight, more preferably 0.6-8 parts by weight, relative to 100 parts by weight of the carrier precursor. In the present invention, controlling the amount of adhesive solvent added within the above range can achieve the effect of both sufficient dissolution and appropriate modification of physical properties, while reducing waste and pollution.

[0062] According to the present invention, preferably, in step (1), the mixture also includes optional extrusion aid, optional binder and optional lubricant.

[0063] In this invention, unless otherwise specified, "optional" means containing or not containing, adding or not adding, or using or not using. Specifically, this invention may or may not include a squeezing aid. There are no particular limitations on the method of adding the additives; they may be added separately or together.

[0064] In this invention, the type of extrusion aid is not particularly limited and can be any conventional extrusion aid in the art, preferably guar gum powder and / or cellulose. The amount of extrusion aid is not particularly limited, and those skilled in the art can make adaptive adjustments as needed to ensure smooth subsequent molding. Preferably, the amount of extrusion aid added relative to 100 parts by weight of the carrier precursor is 0-8 parts by weight, more preferably 0-6 parts by weight.

[0065] In this invention, preferably, the binder is an inorganic binder and / or an organic binder. The binder can function as a binder for the carrier precursor particles.

[0066] In this invention, the type of inorganic binder is not particularly limited and can be any conventional inorganic binder in the art. Preferably, the inorganic binder is selected from at least one of cement, alumina sol, silica sol, zirconium sol, and titanium sol.

[0067] In this invention, the type of organic binder is not particularly limited and can be any conventional organic binder in the art. Preferably, the organic binder is selected from at least one of methylcellulose, ethylcellulose, hydroxypropylcellulose, hydroxypropyl methylcellulose, and microcrystalline cellulose.

[0068] In this invention, the amount of adhesive used is not particularly limited. Those skilled in the art can adapt the addition of adhesive and the amount of adhesive added according to the mixing situation. Preferably, the amount of adhesive added is 0-4 parts by weight relative to 100 parts by weight of carrier precursor, more preferably 0.5-3 parts by weight.

[0069] According to the present invention, the type of lubricant is not particularly limited and can be any conventional lubricant in the art. Those skilled in the art can select the type and amount of lubricant according to the molding effect. Preferably, the lubricant is selected from at least one of glycerin, polyol, polyester, magnesium stearate, stearic acid, talc, and graphite.

[0070] In this invention, preferably, the amount of lubricant added is 0-10 parts by weight, more preferably 0.1-5 parts by weight, relative to 100 parts by weight of the carrier precursor. In this invention, the addition of lubricant has a lubricating effect, which facilitates the smooth progress of molding and, combined with the molding conditions, can improve the average mechanical strength of the catalyst carrier.

[0071] According to the present invention, preferably, the mixing includes dry mixing, kneading, and / or rolling. Preferably, the conditions for kneading and / or rolling include: a kneading and / or rolling time of 5-180 min, more preferably 8-160 min.

[0072] According to a preferred embodiment of the present invention, the mixing process includes: dry mixing the carrier precursor with modified auxiliary oxide, optional extrusion aid, optional binder and optional lubricant for a certain period of time, then adding an aqueous solution containing modified auxiliary and adhesive solvent, and mixing the above raw materials uniformly by kneading and / or rolling.

[0073] According to a preferred embodiment of the present invention, the molding method is selected from at least one of extrusion molding, compression molding, and ball forming. Those skilled in the art can choose conventional molding equipment to perform the molding.

[0074] In this invention, preferably, extrusion molding is used to obtain a catalyst support with high specific surface area and pore volume while also having high mechanical strength, resulting in high preparation efficiency.

[0075] In this invention, the shape of the product obtained by extrusion molding is not particularly limited. Preferably, it is selected from at least one of butterfly shape, cylindrical shape, clover shape, honeycomb shape, Raschig ring shape, and porous profile.

[0076] In this invention, the material before molding also includes optionally mixing the already molded substandard material with water, mixing it evenly by kneading and / or rolling, and then performing final molding. In this invention, mixing the molded product again helps to improve the product qualification rate. The substandard material refers to undried molded strips with rough surfaces, incomplete shapes, and an average mechanical strength below 20 N / mm after random sampling and baking.

[0077] In this invention, preferably, the ratio of the total mass of water added during the mixing process to the weight of the carrier precursor is 0.5-2.5:1, more preferably 0.6-2:1, and even more preferably 0.65-1.6:1.

[0078] In this invention, preferably, the shaped product is dried before calcination. The drying conditions are not particularly limited, and those skilled in the art can choose conventional drying methods and conditions. Preferably, the drying conditions include: a drying temperature of 30-180℃, more preferably 45-160℃, and more preferably 70-140℃; and a drying time of 0.5-100 hours, more preferably 1-80 hours, and more preferably 2-70 hours. According to a preferred embodiment of the invention, the drying process includes: drying at 30-70℃ for 2-50 hours, and then drying at 100-150℃ for 2-20 hours.

[0079] According to the present invention, preferably, the calcination conditions include: a calcination temperature of 750-1150℃, more preferably 850-1050℃; a calcination time of 1-8 hours, more preferably 2-6 hours; and a heating rate of 1-8℃ / minute, more preferably 2-6℃ / minute. In the present invention, high-temperature calcination under the above conditions yields a catalyst support with a high specific surface area.

[0080] In this invention, the mass ratio of the catalyst support to the solution containing the nickel active component is not particularly limited, so that the mass percentage of the nickel active component, calculated as oxide, in the prepared methanation catalyst is 10-20 wt%. Those skilled in the art can make adaptive adjustments according to the impregnation conditions.

[0081] According to the present invention, preferably, the mass concentration of the nickel active component in the solution of the nickel-containing compound is 20-65 wt%, more preferably 25-60 wt%. In the present invention, the above-mentioned catalyst support is used in combination with the nickel active component, the nickel active component provides active sites, and the catalyst support has high mechanical strength. The resulting catalyst, when used in a methanation reaction, exhibits high CO conversion and high methane selectivity, meeting the requirements for long-term operation.

[0082] According to the present invention, the type of nickel-containing compound is not particularly limited, and those skilled in the art can adaptably select water-soluble nickel-containing compounds. Preferably, the nickel-containing compound is selected from at least one of nickel nitrate, basic nickel carbonate, nickel formate, and nickel acetate.

[0083] In this invention, the limitations on the average mechanical strength of the carrier and the dispersion coefficient of the particle mechanical strength are described in the foregoing specification and will not be repeated here.

[0084] According to the present invention, the impregnation conditions are not particularly limited, and those skilled in the art can choose conventional impregnation conditions. Preferably, the impregnation conditions include: an impregnation temperature of 20-80°C, more preferably 25-70°C; and an impregnation time of 0.2-6 hours, more preferably 0.5-4 hours.

[0085] In this invention, preferably, the contact product is dried before calcination, and the drying conditions are not particularly limited. According to a preferred embodiment of the invention, the drying includes: vacuum drying the contact product for 0.5-4 hours, and then air drying at 80-150°C for 1-5 hours.

[0086] In this invention, the drying equipment is not particularly limited, as long as it can achieve the drying effect. Preferably, the vacuum drying is carried out in a rotary evaporator, and the air drying is carried out in an oven.

[0087] According to the present invention, preferably, the calcination conditions include: a calcination temperature of 200-600℃, more preferably 300-500℃; and a calcination time of 1-8 hours, more preferably 2-6 hours.

[0088] According to the present invention, preferably, the mass percentage of the catalyst support is 80-90 wt%, more preferably 81-89 wt%, based on the total mass of the methanation catalyst, and the mass percentage of the nickel active component, based on oxides, is 10-20 wt%, more preferably 11-19 wt%.

[0089] The third aspect of the present invention provides a methanation catalyst prepared by the preparation method described in the second aspect.

[0090] The fourth aspect of this invention provides the application of the methanation catalyst described in the first or third aspect in a methanation reaction.

[0091] The fifth aspect of the present invention provides a methanation method in which H2 / CO feed gas is contacted with the methanation catalyst described in the first or third aspect to carry out a methanation reaction.

[0092] In this invention, preferably, the methanation reaction conditions are: a reaction pressure of 0.1-4 MPa, more preferably 0.5-3 MPa; a reaction temperature of 250-800℃, more preferably 300-600℃; and a gas hourly space velocity of 1000-150000 mL·g. -1 ·h -1 The preferred value is 5000-100000 mL·g -1 ·h -1 The volume ratio of H2 / CO is 1-4:1, preferably 2-3:1.

[0093] In this invention, before the methanation catalyst is used, it is further subjected to a reduction treatment. The reduction treatment steps include: placing the methanation catalyst in a reducing gas atmosphere at normal pressure for reduction, the reduction treatment temperature being 250-750℃, the reduction treatment time being 2-10 hours, and the reducing gas being H2 and / or an inert gas.

[0094] In this invention, the methanation catalyst is subjected to a methanation reaction under the above conditions. The catalyst has high catalytic activity and catalytic stability, as well as high CO conversion rate and high CH4 selectivity.

[0095] The present invention will be described in detail below through examples and comparative examples. Unless otherwise specified, all reagents used in the following examples and comparative examples are commercially available.

[0096] The screw extruder was purchased from the South China University of Technology Science and Technology Industrial Plant, model F-26;

[0097] The test methods and conditions for the specific surface area, pore volume, particle diameter and average mechanical strength of the catalyst support are described in the aforementioned specification and will not be repeated here.

[0098] Example 1

[0099] (1) Prepare the colloidal solvent solution by weighing 2g of citric acid and 6g of lanthanum nitrate, adding 156mL of water and 1.6g of nitric acid with a mass concentration of 63%, and stirring to dissolve.

[0100] (2) 200g of pseudoboehmite powder (purchased from Sasol, 0.75% dry basis) and 6g of guar gum powder were dry-mixed for 10 min. Then, the prepared peptizing solvent solution was added to the dry powder, and the mixture was kneaded for 10 min and then rolled for 40 min to mix evenly. The mixture was then extruded into 4 mm butterfly strips on a screw extruder. The molding temperature was controlled at 45℃ and the molding pressure was 6.5 MPa to obtain the molded product. The temperature change of the material before and after molding was 11℃. The molded product prepared above was dried at 120℃ for 4 hours and calcined at 960℃ for 4 hours with a heating rate of 4℃ / min to obtain catalyst support A1. Figure 1 The image shows the appearance of the extruded strip of the catalyst support prepared in the example.

[0101] (3) Weigh 6.4g of Ni(NO3)2·6H2O and 0.5g of lanthanum nitrate and dissolve them in 12g of deionized water to prepare an impregnation solution. Impregnate 10g of A1 support in the impregnation solution. After standing for 1 hour, place it on a rotary evaporator and vacuum dry at 45℃ for 1.5 hours. Then place it in an oven and dry at 120℃ for 2 hours. The dried sample is then calcined in a muffle furnace at 400℃ for 2 hours. The resulting catalyst is denoted as C1.

[0102] Comparative Example 1

[0103] The catalyst support was prepared according to the method of Example 1, except that the dry mixing time was 2 min and the rolling time was 10 min. Then, it was shaped according to the method of Example 1, and the shaping conditions were kept consistent. Then, it was dried and calcined to obtain catalyst support D1.

[0104] Catalyst supports have poor physicochemical properties and are therefore not selected for catalyst preparation.

[0105] Comparative Example 2

[0106] The catalyst support was prepared according to the method of Example 1, except that the extrusion temperature in step (2) was changed to 30°C, and catalyst support D2 was obtained.

[0107] Catalyst supports have poor physicochemical properties and are therefore not selected for catalyst preparation.

[0108] Example 2

[0109] (1) Prepare the colloidal solvent solution by weighing 3g citric acid, 2g zinc nitrate, and 2g potassium nitrate, adding 166mL water and 1.6g nitric acid with a mass concentration of 63%, and stirring to dissolve.

[0110] (2) 200g of pseudoboehmite powder (purchased from Sasol, 0.75% dry basis) and 6g of guar gum powder were dry-mixed for 10 min. Then, the prepared peptizing solvent solution was added to the dry powder, and the mixture was kneaded for 20 min and then rolled for 40 min to mix evenly. The mixture was then extruded into 4 mm butterfly strips on a screw extruder. The molding temperature was controlled at 50℃ and the molding pressure was 6 MPa to obtain the molded product. The temperature change of the material before and after molding was 11℃. The molded product prepared above was dried at 120℃ for 4 hours and calcined at 960℃ for 4 hours with a heating rate of 4℃ / min to obtain catalyst support A2.

[0111] (3) The catalyst support A2 was prepared according to the method of step (3) in Example 1, and the resulting catalyst was denoted as C2.

[0112] Example 3

[0113] (1) Prepare the colloidal solvent solution by weighing 11.12g of aluminum nitrate and 5g of magnesium nitrate, adding 165mL of water, and stirring to dissolve.

[0114] (2) 200g of pseudoboehmite powder (purchased from Sasol, 0.75% dry basis) and 6g of guar gum powder were dry-mixed for 10 min. Then, the prepared peptizing solvent solution was added to the dry powder, and the mixture was kneaded for 20 min and then rolled for 50 min. The resulting material was extruded into 4 mm butterfly strips on a screw extruder. The molding temperature was controlled at 45℃ and the molding pressure at 8 MPa to obtain the molded product. The temperature change of the material before and after molding was 7℃. The molded product prepared above was dried at 120℃ for 4 hours and calcined at 1000℃ for 4 hours at a heating rate of 4℃ / min to obtain catalyst support A3.

[0115] (3) The catalyst support A3 was prepared according to the method of step (3) in Example 1, and the resulting catalyst was denoted as C3.

[0116] Example 4

[0117] (1) Prepare the colloidal solvent solution by weighing 2.4g of 63% nitric acid, adding 4g of glycerol, 2g of potassium nitrate and 6g of lanthanum nitrate, adding 164mL of water and stirring to dissolve.

[0118] (2) 200g of pseudoboehmite powder (purchased from Sasol, 0.75% dry basis) and 6g of guar gum powder were mixed evenly for 10 min. Then, the prepared peptizing solution was added to the dry powder. The mixture was kneaded for 20 min and rolled for 50 min. The mixture was then extruded into 4 mm X-shaped strips on a screw extruder. The molding temperature was controlled at 35℃ and the molding pressure at 8.5 MPa to obtain the molded product. The temperature change of the material before and after molding was 7℃. The molded product prepared above was dried at 100℃ for 4 hours and calcined at 960℃ for 4 hours with a heating rate of 4℃ / min to obtain catalyst support A4.

[0119] (3) The catalyst support A4 was prepared according to the method of step (3) in Example 1, and the resulting catalyst was denoted as C4.

[0120] Example 5

[0121] (1) Prepare the adhesive solvent solution by weighing 2.4g of 63% nitric acid, adding 6g of lanthanum nitrate as a modifier, adding 162mL of water, and stirring to dissolve.

[0122] (2) 200g of pseudoboehmite powder (purchased from Sasol, 0.75% dry basis), 10g of guar gum powder, 5g of modified calcium oxide, and 2g of methylcellulose were mixed evenly for 10 minutes. Then, the prepared peptone solution was added to the dry powder. The mixture was kneaded for 80 minutes until homogeneous, and then extruded into 4mm butterfly strips on a plunger extruder. The molding temperature was controlled at 45℃ and the molding pressure at 9MPa to obtain the molded product. The temperature change of the material before and after molding was 8℃. The molded product was dried at 120℃ for 4 hours and calcined at 1000℃ for 4 hours at a heating rate of 3℃ / min to obtain catalyst support A5.

[0123] (3) The catalyst support A5 was prepared according to the method of step (3) in Example 1, and the resulting catalyst was denoted as C5.

[0124] Example 6

[0125] (1) Prepare the colloidal solvent solution by weighing 2.4g of 63% nitric acid, adding 6g of lanthanum nitrate, and adding 156mL of water and stirring to dissolve.

[0126] (2) 200g of pseudoboehmite powder (purchased from Sasol, 0.75% dry basis), 6g of guar gum powder, 7g of modified magnesium oxide, and 4g of methylcellulose were mixed evenly for 10 minutes. Then, the prepared peptizing solvent solution was added to the dry powder. The mixture was kneaded for 5 minutes, then rolled for 90 minutes to mix evenly. The mixture was then extruded into 4mm butterfly strips on a plunger extruder. The molding temperature was controlled at 40℃ and the molding pressure at 10MPa to obtain the molded product. The temperature change of the material before and after molding was 9℃. The molded product was dried at 120℃ for 4 hours and calcined at 1000℃ for 4 hours at a heating rate of 3℃ / min to obtain catalyst support A6.

[0127] (3) The catalyst support A6 was prepared according to the method of step (3) in Example 1, and the resulting catalyst was denoted as C6.

[0128] Comparative Example 3

[0129] The catalyst support was prepared according to the method of Example 6, except that the mixing and rolling was carried out for 20 minutes, the molding temperature was 35°C, the temperature change before and after molding was 6°C, and the molding pressure was 3.5 MPa, thus obtaining catalyst support D3.

[0130] Catalyst supports have poor physicochemical properties and are therefore not selected for catalyst preparation.

[0131] Comparative Example 4

[0132] The catalyst support was prepared according to the method in Example 6, except that the amount of nitric acid added was 4g, the molding temperature was 55℃, the temperature change before and after molding was 16℃, and the molding pressure was 12.5MPa, resulting in catalyst support D4. Due to the high pressure, the perforated plate was damaged, and the shape of some extruded strips was altered. The catalyst support had poor physicochemical properties and was not selected for catalyst preparation.

[0133] Example 7

[0134] Add 10g of water to the defective extruded strip after Comparative Example 1 and continue mixing and grinding for 40 minutes. The resulting material is shaped and dried and calcined according to the conditions of Example 1 to obtain catalyst carrier A7.

[0135] The catalyst was prepared by catalyst support A7 according to step (3) of Example 1, and the resulting catalyst was denoted as C7.

[0136] Example 8

[0137] (1) Prepare the gel solvent solution by dissolving 11.12g of aluminum nitrate in 150mL of water.

[0138] (2) 200g of pseudoboehmite powder (purchased from Sasol) was mixed with 6g of guar gum powder, 6g of modified magnesia, and 2g of calcium oxide for 10 min. Then, the prepared peptizing solvent solution was added to the dry powder. The mixture was then kneaded for 30 min and rolled for 70 min to achieve uniform mixing. The mixture was then extruded into 6 mm butterfly strips on a plunger extruder. The molding temperature was controlled at 35℃ and the molding pressure at 5 MPa to obtain the molded product. The temperature change of the material before and after molding was 6℃. The molded product prepared above was placed at room temperature for 24 h, dried at 90℃ for 4 h, and calcined at 1000℃ for 4 h with a heating rate of 2℃ / min to obtain catalyst support A8.

[0139] (3) The catalyst support A8 was prepared according to the method of step (3) in Example 1, and the resulting catalyst was denoted as C8.

[0140] Example 9

[0141] (1) Prepare the colloidal solvent solution by weighing 2.4g of 63% nitric acid and 2g of citric acid, adding 6g of lanthanum nitrate and 168mL of water, and stirring to dissolve.

[0142] (2) 200g of boehmite powder (purchased from Sasol), 6g of guar gum powder, 6g of magnesium oxide, and 2g of methylcellulose were mixed evenly for 10 min. Then, the prepared adhesive solvent solution was added to the dry powder, and the mixture was kneaded for 30 min and rolled for 90 min to mix evenly. The mixture was then extruded into 6 mm butterfly strips on a plunger extruder. The molding temperature was controlled at 30℃ and the molding pressure was 6.8 MPa to obtain the molded product. The temperature change of the material before and after molding was 6℃. The molded product was placed at room temperature for 48 h, dried at 90℃ for 4 h, and calcined at 1000℃ for 4 h with a heating rate of 2℃ / min to obtain catalyst support A9.

[0143] (3) The catalyst support A9 was prepared according to the method of step (3) in Example 1, and the resulting catalyst was denoted as C9.

[0144] Example 10

[0145] (1) Prepare the colloidal solvent solution by weighing 6g of 63% nitric acid, adding 6g of lanthanum nitrate, adding 210mL of water, and stirring to dissolve.

[0146] 200g of carbonized pseudoboehmite powder (0.7% dry basis) and 6g of guar gum powder were mixed for 10 minutes. Then, the prepared peptizing solvent solution was added to the dry powder, and the mixture was kneaded for 30 minutes and then rolled for 80 minutes to achieve uniform mixing. The resulting material was extruded into 6mm butterfly strips using a plunger extruder. The molding temperature was controlled at 20℃ and the molding pressure at 7MPa to obtain the molded product. The temperature change of the material before and after molding was 10℃. The molded product was dried at 60℃ for 24 hours, and the dried strips were calcined at 960℃ for 4 hours at a heating rate of 2℃ / min to obtain catalyst support A10.

[0147] (3) The catalyst support A10 was prepared according to the method of step (3) in Example 1, and the resulting catalyst was denoted as C10.

[0148] Example 11

[0149] To prepare a basic nickel carbonate impregnation solution and a nickel salt solution: Add 7.8 g of ammonium carbonate to 11.7 g of concentrated ammonia water, stir to dissolve, then add 3.25 g of basic nickel carbonate. Slowly heat to 45°C and stir until dissolved to obtain a nickel-containing impregnation solution. Contact this impregnation solution with 10 g of A6 support, allow to stand for 1 hour, then vacuum dry at 40°C for 1.5 hours using a rotary evaporator, followed by drying in an oven at 140°C for 2 hours. The dried sample is then calcined in a muffle furnace at 450°C for 4 hours. The resulting catalyst is designated C11.

[0150] Test Example 1

[0151] The specific surface area, pore volume, average mechanical strength, and coefficient of variation of the prepared catalyst supports are shown in Table 1. The coefficient of variation was calculated for each group of catalyst support particles consisting of 22 particles.

[0152] Table 1

[0153]

[0154]

[0155] As can be seen from Table 1, the catalyst supports prepared in Examples 1-10 exhibit significantly improved mechanical strength compared to Comparative Examples 1 and 2. Therefore, the method for preparing catalyst supports provided by the present invention possesses higher specific surface area and mechanical strength.

[0156] Figure 2 This is a schematic diagram of the mechanical strength distribution of the carrier in Examples 2, 6, and 3. Figure 2 As can be seen from this, the method for preparing catalyst supports provided by the present invention not only has high mechanical strength, but also low strength dispersion, which is beneficial for the catalyst to maintain stable mechanical strength in application and improve its practicality.

[0157] Test Example 2

[0158] C1-C11 catalysts were sieved to 10-20 mesh, and 10g of each was weighed and loaded into the reactor. Activation was performed by reduction at 500℃ for 3 hours under a pure hydrogen atmosphere at atmospheric pressure. After reduction, the temperature was lowered to 320℃ under a hydrogen atmosphere, and the feed gas (H2 / CO volume ratio of 3:1) was switched to continue the reaction at a space velocity of 10000 mL·g⁻¹. -1 ·h -1 The reaction pressure was 2 MPa. The tail gas composition was analyzed by online gas chromatography, and the CO conversion rate and CH4 selectivity were calculated. The results are shown in Table 2.

[0159] Table 2

[0160]

[0161]

[0162] As can be seen from Table 2, the catalyst prepared by the high-strength support provided by the present invention has good catalytic performance, with high CO conversion rate and CH4 selectivity.

[0163] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A methanation catalyst, characterized in that, The methanation catalyst contains a catalyst support and a nickel-active component; Based on the total mass of the methanation catalyst, the catalyst support comprises 80-90 wt% by mass, and the active nickel component, calculated as oxides, comprises 10-20 wt% by mass. The catalyst support has an average mechanical strength of 35-80 N / mm; The particle mechanical strength dispersion coefficient of the catalyst support is in the range of 0-0.55; the particle diameter of the catalyst support is 3-20 mm. The catalyst support is selected from alumina; The method for preparing the catalyst includes: (1) The catalyst support is obtained by mixing the support precursor with the colloidal solvent, and then molding and calcining. (2) The catalyst support is impregnated in a solution containing nickel compounds and then calcined to obtain a methanation catalyst; Wherein, the temperature change of the material before and after molding is less than 15°C; the mixing includes dry mixing, kneading and / or rolling. The conditions for kneading and / or rolling include: a kneading and / or rolling time of 8-160 min; the conditions for molding include: a molding temperature of 5-50℃; and a molding pressure of 4-15 MPa.

2. The catalyst according to claim 1, wherein, The catalyst support contains 81-89 wt% of the total mass of the methanation catalyst, and the nickel active component contains 11-19 wt% of the total mass of the catalyst, calculated as oxides.

3. The catalyst according to claim 1, wherein, The catalyst support has an average mechanical strength of 38-75 N / mm.

4. The catalyst according to claim 1, wherein, The specific surface area of ​​the catalyst support is 60-130 m². 2 / g; And / or, the pore volume of the catalyst support is 0.3-0.6 mL / g.

5. The catalyst according to claim 4, wherein, The specific surface area of ​​the catalyst support is 70-120 m². 2 / g; And / or, the pore volume of the catalyst support is 0.35-0.55 mL / g.

6. The catalyst according to claim 1, wherein, The particle mechanical strength dispersion coefficient of the catalyst support is in the range of 0.15-0.

52.

7. A method for preparing the methanation catalyst according to any one of claims 1-6, characterized in that, The method includes: (1) The catalyst support is obtained by mixing the support precursor with the colloidal solvent, and then molding and calcining. (2) The catalyst support is impregnated in a solution containing nickel compounds and then calcined to obtain a methanation catalyst; Wherein, the temperature change of the material before and after molding is less than 15°C; the mixing includes dry mixing, kneading and / or rolling. The conditions for kneading and / or rolling include: a kneading and / or rolling time of 8-160 min; the conditions for molding include: a molding temperature of 5-50℃; and a molding pressure of 4-15 MPa. The carrier is selected from alumina.

8. The preparation method according to claim 7, wherein, The temperature change of the material before and after molding is less than 12℃.

9. The preparation method according to claim 7, wherein, In the solution of the nickel-containing compound, the concentration of the active nickel component is 20-65 wt%.

10. The preparation method according to claim 9, wherein, In the solution of the nickel-containing compound, the concentration of the active nickel component is 25-60 wt%.

11. The preparation method according to claim 7, wherein, The nickel-containing compound is selected from at least one of nickel nitrate, basic nickel carbonate, nickel formate, and nickel acetate.

12. The preparation method according to claim 7, wherein, The impregnation conditions include: an impregnation temperature of 20-80℃; and an impregnation time of 0.2-6 hours. And / or, the calcination conditions include: a calcination temperature of 200-600℃; and a calcination time of 1-8 hours.

13. The preparation method according to claim 12, wherein, The impregnation conditions include: an impregnation temperature of 25-70℃; and an impregnation time of 0.5-4 hours. And / or, the calcination conditions include: a calcination temperature of 300-500℃; and a calcination time of 2-6 hours.

14. The preparation method according to claim 7, wherein, The catalyst support comprises 80-90 wt% of the total mass of the methanation catalyst, and the active nickel component comprises 10-20 wt% of the total mass of the oxide.

15. The preparation method according to claim 14, wherein, The catalyst support contains 81-89 wt% of the total mass of the methanation catalyst, and the nickel active component contains 11-19 wt% of the total mass of the catalyst, calculated as oxides.

16. The preparation method according to claim 7, wherein, In step (1), the mixing also includes adding water and modifying agents.

17. The preparation method according to claim 16, wherein, Based on a carrier precursor weight of 1g, the volume of water added is 0.6-1mL.

18. The preparation method according to claim 17, wherein, Based on a carrier precursor weight of 1g, the volume of water added is 0.65-0.95mL.

19. The preparation method according to claim 16, wherein, The modifying agent is selected from at least one of compounds containing alkali metal elements, alkaline earth metal elements, and rare earth metal elements.

20. The preparation method according to claim 19, wherein, The modifying agent is selected from at least one of oxides, carbonates, basic carbonates, organic salts, nitrates, and hydroxides of alkali metals, alkaline earth metals, and rare earth metals.

21. The preparation method according to claim 20, wherein, The modifying agent is selected from at least one of lanthanum nitrate, magnesium nitrate, zinc nitrate, potassium nitrate, magnesium oxide, calcium oxide, lanthanum acetate, and magnesium acetate.

22. The preparation method according to claim 19, wherein, The amount of the modifying agent added is 0.6-15 parts by weight relative to 100 parts by weight of the carrier precursor.

23. The preparation method according to claim 22, wherein, The amount of the modifying agent added is 0.8-12 parts by weight relative to 100 parts by weight of the carrier precursor.

24. The preparation method according to claim 7, wherein, The carrier precursor is a substance that is converted into a carrier through subsequent calcination.

25. The preparation method according to claim 24, wherein, The carrier precursor is selected from boehmite.

26. The preparation method according to claim 7, wherein, The adhesive solvent is an organic acid and / or an inorganic acid; And / or, relative to 100 parts by weight of the carrier precursor, the amount of the adhesive solvent added is 0.4-10 parts by weight.

27. The preparation method according to claim 26, wherein, The adhesive solvent is selected from at least one of nitric acid, aluminum nitrate, acetic acid, and citric acid; And / or, relative to 100 parts by weight of the carrier precursor, the amount of the adhesive solvent added is 0.6-8 parts by weight.

28. The preparation method according to claim 7, wherein, In step (1), the mixture may also include optional extrusion aids, optional binders and optional lubricants.

29. The preparation method according to claim 7, wherein, The molding method is selected from at least one of extrusion molding, compression molding, and ball forming; And / or, the calcination conditions include: a calcination temperature of 750-1150℃; a calcination time of 1-8 hours; and a heating rate of 1-8℃ / minute.

30. The preparation method according to claim 29, wherein, The roasting conditions include: a roasting temperature of 850-1050℃; a roasting time of 2-6 hours; and a heating rate of 2-6℃ / minute.

31. The methanation catalyst prepared by the method according to any one of claims 7-30.

32. The use of the methanation catalyst according to any one of claims 1-6, 31 in the methanation reaction.

33. A methanation method, characterized in that, The H2 / CO feed gas is contacted with the methanation catalyst described in any one of claims 1-6 and 31 to carry out a methanation reaction.

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