29 results about "Industrial catalysts" patented technology

The invention discloses a high-sulfur-tolerance SCR honeycomb denitration catalyst and a preparation method thereof, and belongs to the technical field of industrial catalysts.The preparation method comprises the steps that S1, anatase type TiO2 and NH4HCO3 are mixed for pulping, pre-drying and calcination are conducted after extrusion forming, and a green body is formed; s2, carrying out nitric acid treatment on the green body, dipping the green body in a mixed solution of copper nitrate hydrate and cerium nitrate hydrate, and carrying out vacuum dipping, microwave drying and two-stage calcination to obtain a desulfurization carrier; s3, depositing an ammonium metatungstate precursor on the surface of the desulfurization carrier through CVD, and calcining to form a WO3 transition layer; and S4, dipping the transition layer in an acid solution containing NH4VO3 and ammonium metatungstate, and calcining after ultrasonic treatment to obtain a finished product. According to the method, the pore structure of the carrier is optimized through chambering treatment, and the stability and denitration efficiency of the catalyst in high-sulfur flue gas are remarkably improved by combining a multistage sulfur-resistant mechanism that the desulfurization layer preferentially captures SO2, the WO3 transition layer obstructs sulfur penetration and the denitration layer is protected by active sites.

The invention discloses a sodium metavanadate-based catalyst activity gradient regulation and regeneration system and method, and relates to the technical field of industrial catalyst regeneration, the sodium metavanadate-based catalyst is of a unique layered structure, the sodium metavanadate-based catalyst comprises an outer layer, a middle layer and an inner layer from the surface to the interior in sequence, and active components and doping elements of all the layers are different; the outer layer is doped with high-content sodium metavanadate and manganese oxide, reactant molecules can be quickly adsorbed and activated in the initial stage of the reaction, the manganese oxide can provide additional active sites, reduce reaction activation energy and promote quick start of the reaction, and the middle layer is doped with a proper amount of sodium metavanadate and cerium oxide, so that the reaction is more stable in the process of the reaction. The cerium oxide can adjust migration and conversion of oxygen species on the surface of the catalyst, optimize the reaction path, improve the selectivity of a target product and reduce side reactions, the inner layer is doped with the low-content sodium metavanadate and tungsten oxide, and the structural stability of the catalyst under high-temperature and long-time reaction is maintained by means of the high stability of the tungsten oxide.

The invention discloses a temperature control system for industrial catalyst regeneration, which relates to the technical field of temperature control and consists of an initialization module, a decision module, an acquisition module and an execution module. The initialization module obtains multi-dimensional key parameters through the multi-dimensional sensor array; the initialization module constructs a multi-parameter coupling correlation model based on attenuation mapping of catalyst activity and core parameters, introduces a dynamic weight coefficient to correct an influence weight, carries out error compensation in combination with a negative correlation between a characteristic by-product in a product and activity, and accurately calculates a current activity predicted value of the catalyst. The decision-making module is based on a temperature activity response model, takes a thermal stability threshold as a constraint, and solves the optimal heat treatment temperature and temperature control duration through a particle swarm optimization algorithm; the acquisition module acquires parameters during regeneration; the execution module determines the initial heating power according to the optimal parameters and adjusts the medium flow to guarantee the uniformity of a temperature field, and self-adaptive correction is implemented in combination with differential pressure recovery curve deviation comparison, so that closed-loop precise temperature control is achieved.

The application provides a composite material containing metal composite nanoparticles, which comprises metal composite nanoparticles, a heteroatom-doped carbon layer and a carrier; the surface of the carrier is composited with the heteroatom-doped carbon layer; and the metal composite nanoparticles are loaded on the surface of the carrier and embedded in the heteroatom-doped carbon layer. The carbon layer semi-limited domain stable metal heterostructure composite material designed by the application has metal heterojunction nanoparticles with a diameter of 2-20 nm and a 2-8 layer semi-limited domain graphene structure carbon layer; the semi-limited domain structure of the carbon layer can realize high stability of the metal nanoparticles, and the exposed metal active sites are beneficial to the adsorption of reaction molecules, thereby ensuring efficient reaction. The catalyst prepared by the application meets the requirements of high activity and stability of industrial catalysts, has excellent universality, low cost and is easy to realize mass production, and can be popularized in industrial production.

The application discloses a cobalt silicate modified platinum-based catalyst, a preparation method and application, and belongs to the technical field of industrial catalysts. The platinum-based catalyst comprises a carrier, a cobalt silicate modification layer generated in situ on the carrier, and platinum nanoparticles loaded on the cobalt silicate modification layer; the cobalt silicate modification layer is a continuous fibrous structure and is covalently combined with the carrier through Si-O-Co bonds. The cobalt silicate modification layer realizes anchoring and electron transfer of the platinum nanoparticles, makes the platinum in an electron-rich state, weakens adsorption on an alpha, beta-unsaturated aldehyde C=C bond, and strengthens selective adsorption on a C=O bond; when the catalyst is applied to selective hydrogenation of alpha, beta-unsaturated aldehydes, the conversion rate of cinnamyl aldehyde can reach 98.2%, the selectivity of cinnamyl alcohol can reach 92.0%, and the catalyst is suitable for hydrogenation of various alpha, beta-unsaturated aldehydes such as aromatic aldehydes, aliphatic aldehydes and furan aldehydes, and has excellent catalytic activity, selectivity and stability, and good industrial application prospect.

The invention belongs to the technical field of preparation of industrial catalysts, and discloses a catalyst for dehydrogenation of long-chain alkane containing rare earth metal as well as preparation and application of the catalyst. According to the catalyst, a specific type of rare earth metal is introduced as an electronic and structural cocatalyst, so that the selectivity of the catalyst to straight-chain monoolefine is remarkably improved, and the carbon deposition resistance and the thermal stability of the catalyst are greatly enhanced, thereby prolonging the service life and the regeneration period of the catalyst. The preparation method of the catalyst is simple in process and easy for industrial production, and can realize highly uniform dispersion of the active component and the auxiliary agent on the carrier. The catalyst is a long-chain alkane dehydrogenation catalyst which still has high activity, high selectivity and high stability under the condition of low platinum loading capacity (0.15%). The method has the advantages that side reaction and carbon deposition generation can be effectively inhibited, the service life is remarkably prolonged, and the method has important industrial application value for reducing the production cost of the linear alkylbenzene and improving the product quality.

This invention discloses a neodymium-praseodymium-doped magnesium aluminum oxide catalyst, its preparation method, and its application, relating to the field of industrial catalyst preparation technology. The catalyst is a magnesium, aluminum, neodymium, and praseodymium composite oxide, composed of rare earth oxides Nd₂O₃ and Pr₆O₂. 11 It is constructed by supporting MgO on an Al2O3 support, and is represented as Nd2O3-Pr6O 11 / MgO-Al2O3, wherein the mass fraction of MgO-Al2O3 support is 70%–80%, the mass fraction of Nd2O3 is 3.3%–20%, and the mass fraction of Pr6O is... 11 The mass fraction of MgO is 4%–25%, and the mass fraction of MgO in the MgO-Al2O3 support is 1%–5%. The preparation process is simple and convenient, requiring no complex equipment, and is suitable for large-scale industrial production. At the same time, the catalyst has a high specific surface area and uniformly dispersed active centers, exhibiting high catalytic activity, good selectivity, and strong stability, which can effectively reduce the formation of by-products and improve the purity of methyl acetophenone.

This application discloses a method for preparing high-strength special carbon spheres, the special carbon spheres themselves, and their applications. The method involves mixing sulfur with polymer spheres and then subjecting them to co-heat treatment. The high affinity of sulfur is used to strip hydrogen elements from the polymer, suppressing carbon loss during carbonization. Subsequent heating and carbonization yields special carbon spheres with high mechanical strength, high carbon yield, and high specific surface area. The crushing strength of the carbon spheres exceeds 50 N, reaching a maximum of 260 N, and the product yield is greater than 70%, reaching a maximum of 91.2%. This method offers advantages such as simple process, low energy consumption, high yield, environmental friendliness, and scalability. Furthermore, the obtained carbon spheres exhibit excellent performance in gas adsorption and separation, as well as catalysis, and are particularly suitable for high-space velocity applications in electronic specialty gas purification and trace impurity gas separation, as well as for industrial catalyst supports.

The application belongs to the technical field of catalyst drying, in particular to a VOC industrial catalyst mesh belt type drying furnace, which comprises a feeding table, the surface of the feeding table is provided with a conveying mesh belt, and one end of the feeding table is provided with a heating furnace. By arranging the adjusting frame and the placing cylinder, the carrier is placed in the interior of the placing cylinder before drying, the placing cylinder drives the carrier to move upward, and finally the carrier abuts against the cover and pushes it open. When the abutting cover is pushed open, the lower sealing plate is automatically opened, so that the carrier is connected with the lower end opening of the material containing frame. At this time, the upper sealing plate is also gradually opened, so that the internal slurry directly contacts the carrier, and cooperates with the pressing of the pressing plate, so that the slurry is poured into the interior of the carrier. At this time, the motor at one end of the second intermittent tooth is started, cooperates with the elastic force of the coil spring, so that the placing plate at the lower end of the carrier reciprocatingly moves, so that the carrier slightly jolts, so that the slurry is completely filled in the carrier, and the probability of uneven filling of the slurry is reduced.

The invention discloses a modified gamma-Al2O3 catalyst as well as a preparation method and application thereof, and belongs to the technical field of industrial catalyst preparation. The invention relates to a preparation method of a modified gamma-Al2O3 catalyst, which comprises the following steps: adding a triblock copolymer into an organic solvent, then adding nitric acid and a precursor, heating and stirring the obtained mixture to react, then heating and evaporating to dryness, and drying and roasting the obtained solid to obtain the modified gamma-Al2O3 catalyst, the metal source is selected from lanthanum nitrate, cerium nitrate or zirconium nitrate. The modified gamma-Al2O3 catalyst synthesized through the one-pot method is used for synthesizing anisole through the oxygen alkylation reaction of phenol and dimethyl carbonate, and has good conversion rate and excellent selectivity.

The invention relates to a p-phenyl dithio isocyanate dimer and a preparation method thereof, belongs to the technical field of organic synthesis, and is used for solving at least one of the problems of long-time reaction under a high-temperature condition, environmental pollution and the like in catalysis of an existing method. According to the preparation method disclosed by the invention, p-phenyl dithio isocyanate is selected as a synthetic substrate, an STM-BJ technology is utilized to construct atomic-scale nanogold as a catalyst, and the atomic-scale nanogold is catalyzed to carry out dimerization; compared with a traditional industrial catalyst, the method has the advantages that the reaction can be completed in hundreds of milliseconds, the reaction time is short, and the method is green, environmentally friendly and low in toxicity, and the catalyst can be recycled and reused.

The application discloses a kind of coal direct liquefaction high reactivity raw material and its preparation method, the preparation method includes: (1) the solution containing ferrous sulfate and ammonia are sent into fast precipitation reactor, to obtain divalent iron precipitate slurry;Then from the atomization of the nozzle of drying tower is sprayed, forms iron precipitate droplet;(2) iron precipitate droplet is dried in drying tower by hot air, forms hydrated iron oxide solid particle;(3) hydrated iron oxide solid particle enters vacuum belt filter in the bottom of drying tower, uses water spray washing, removes the byproduct ammonium sulfate enriched on the surface of solid particle;(4) after washing, hydrated iron oxide solid particle and washing fine coal particle are together into drying mill and are mixed, grinds and dries, and is made into coal direct liquefaction high reactivity raw material.The application solves the problems that active component of catalyst is easy to aggregate in prior art, mixing and dispersion between active component and reactant coal powder are poor, and industrial catalyst production process is long, and water consumption is large.

The invention discloses a preparation method of a Co3O4 (at) Z-ZIS catalyst for preparing methyl formate by co-conversion of CO2 and methanol through photo-thermal catalysis. Gasification fine slag generated after coal gasification is subjected to drying, screening, acid pickling, water washing, drying, alkaline leaching, water washing and drying processes to synthesize Na-P1 type zeolite. The preparation method comprises the following steps: growing indium zinc sulfide on Na-P1 type zeolite in situ by adopting a hydrothermal method, and loading Co metal oxide by adopting the hydrothermal method to finally prepare the novel efficient photo-thermal catalyst Co3O4 (at) Z-ZIS. Compared with the existing industrial catalyst, the catalyst Co3O4 (at) Z-ZIS shows excellent photo-thermal catalytic performance under the mild conditions of normal pressure and lower temperature. When the catalyst is applied to a reaction for preparing methyl formate through partial oxidative dehydrogenation of methanol in a CO2 atmosphere, the catalytic efficiency is remarkably improved.

The invention relates to a regeneration method of a deactivated benzene hydrogenation catalyst, which comprises the following steps: purging the deactivated benzene hydrogenation catalyst in an inert atmosphere at 130-300 DEG C for 1-8 hours so as to remove materials such as benzene attached to the surface, thereby obtaining a debenzolized catalyst; soaking the debenzolized catalyst in polyhydric alcohol for 2 to 30 hours under the conditions that the temperature is 100 to 300 DEG C and the pressure is 0.1 to 3 MPa; and after soaking is finished, cooling, emptying the polyol, washing the catalyst with a solvent, and then purging with high-temperature inert gas to remove the solvent. According to the method, surface deposited silicon is selectively removed from an industrial hydrodesulfurization deactivated catalyst through a glycerol depolymerization process, and the activity and physical properties of the catalyst are recovered. The method provides a new technical means for regeneration of the industrial catalyst, and realizes reutilization of the catalyst deactivated due to silicon poisoning.

The utility model relates to the technical field of catalyst purging. The utility model discloses an industrial catalyst purging device convenient for observation, which comprises a purging chamber, observation windows fixedly connected to two sides of the purging chamber, a guide rail fixedly connected to the inner side of the purging chamber, an air distribution pipe fixedly connected to the top of the guide rail, and protection components fixedly connected to two sides of the purging chamber, the top of the inner wall of the purging chamber is fixedly connected with a searchlight, the outer side of the guide rail is slidably connected with a purging assembly, through the arrangement of the searchlight, uniform and sufficient illumination is provided for the interior of the purging chamber, shadows are eliminated, a clear and bright visual field is provided for manual hole blockage inspection with naked eyes, a servo motor is started to drive a rubber pressing wheel to rotate, and the purging assembly is driven to rotate; and the rubber pressing wheel rotates reversely through friction force in the rotating process, so that the deflection angle of the air knife can be adjusted, the surface of the catalyst can be blown in all directions, and redundant slurry is effectively removed.

The invention belongs to the field of industrial catalysts, and relates to a low-sodium silver-containing raw material, a preparation method thereof, a silver impregnation liquid, a silver catalyst and a method for producing ethylene oxide through ethylene epoxidation. The preparation method of the low-sodium silver-containing raw material comprises the following steps that I, a homogeneous solution A is obtained, the homogeneous solution A is a sodium removal agent water-based solution, and a sodium removal agent comprises organic acid, optional organic alcohol and optional organic ether; and II, treating a silver oxide raw material by adopting the homogeneous solution A obtained in the step I, and filtering out a liquid-phase component to obtain the low-sodium silver-containing raw material. According to the method, the silver oxide raw material is subjected to sodium removal treatment to obtain the low-sodium silver-containing raw material, the low-sodium silver-containing raw material is used for preparing the silver impregnation liquid, and the selectivity and activity of the prepared silver catalyst are further improved.

This invention provides an industrial catalyst support, a catalyst, and its application in the conversion of syngas to higher alcohols. The catalyst support comprises silica, a colloidal solvent, and a metal salt; the metal element comprises 0.1% to 5% of the silica mass, and is selected from one or more of Na, K, Mg, Ca, Mn, La, Sm, Ce, or Zr. This support possesses excellent mechanical strength, a large specific surface area, and abundant pore structure. Furthermore, the preparation method is simple and reproducible, making it suitable for large-scale industrial production. The catalyst prepared using this support not only exhibits excellent mechanical strength and abundant pore structure but also significantly enhances the catalytic activity and selectivity of the Fischer-Tropsch synthesis catalyst in the conversion of syngas to higher alcohols, thus possessing significant application value in industrial fields.

This invention belongs to the field of industrial catalyst technology, specifically disclosing a bismuth molybdate-based composite catalyst and its preparation method and application. The preparation method of the bismuth molybdate-based composite catalyst is as follows: (1) Under the conditions of maintaining a water bath and stirring, bismuth salt, iron salt, nickel salt, cobalt salt, potassium salt and manganese salt are added to an alcohol solution containing ammonium molybdate. After reaction aging, a precursor solution is prepared; (2) Clean alkaline alumina particles are added to the precursor solution as a carrier, ultrasonically dispersed and then allowed to stand; the treated alkaline alumina particles are taken out and subjected to water vapor synergistic slow precipitation for 3-10 days to obtain catalyst particles that have completed crystallization; (3) The catalyst particles that have completed crystallization are dried and calcined to obtain the bismuth molybdate-based composite catalyst. The bismuth molybdate-based composite catalyst has good catalytic performance and strong stability. It is not easy to pulverize, fall off and degrade in performance. It can be used to stably and efficiently produce acrolein under high load conditions.

This invention belongs to the field of industrial catalysts, and relates to an α-alumina support and its preparation method, as well as a method for producing ethylene oxide via silver catalyst and ethylene epoxidation. The α-alumina support has the following characteristics: α-Al₂O₃ content is above 90% by weight; crushing strength is 80–200 N / particle; specific surface area is 1.0–3.0 m² / particle. 2 / g; water absorption rate 30-70%; pore volume 0.30-0.75mL / g; the pore distribution curve has a bimodal structure, including macropore peaks and micropore peaks, with pores of 1.5-2.5μm accounting for more than 95% of the total pore volume of the micropore peaks; and plate-like crystals with a crystal size of 3-5μm accounting for more than 90% of the total plate-like crystals. Compared with the prior art, the silver catalyst prepared on the α-alumina support provided by this invention, when used for the oxidation of ethylene to ethylene oxide, has the advantages of higher selectivity and stability while ensuring activity.

The invention discloses a high-selectivity and high-stability catalyst for preparing methanol from carbon dioxide as well as a preparation method and application of the high-selectivity and high-stability catalyst, and belongs to the field of catalysts. The catalyst comprises a carrier and a catalytic component loaded on the carrier, the catalytic component is a copper nanocluster material or copper-based nanoparticles enriched with oxidation-state copper atoms; the catalytic component is dispersed inside and / or on the surface of the metal organic framework in an atomic form, and the catalytic component accounts for 10-50wt% of the total mass of the catalyst in terms of copper. The catalyst disclosed by the invention has the characteristic of high active metal dispersity, a synergistic effect exists among atomic-scale dispersed copper-zinc active sites, the number of copper active centers is controllable, a new zinc source is introduced as a catalytic active center, and methanol preparation through carbon dioxide hydrogenation under relatively wide temperature and pressure intervals can be realized on the catalytic effect; compared with a conventional industrial catalyst, the catalyst provided by the invention has a better reaction effect and shows excellent stability in the reaction process.

The application discloses a kind of preparation methods of magnetic carboxyl chitosan microsphere metal organic framework core-shell structure industrial catalyst, which is prepared by ultrasonic-assisted reverse emulsion polymerization and green crosslinking agent carboxyl chitosan coated ferroferric oxide microspheres, then in-situ growth metal organic framework on the surface of microsphere, then reduce palladium ion in the pore of metal organic framework, and then prepare core-shell structure industrial catalyst with uniform particle size, strong stability, high efficiency, magnetism, reusable.The large specific surface area and pore structure of metal organic framework provide a large number of fixed sites for palladium atoms, increase the contact area and probability of catalyst and reactant, significantly improve the catalytic activity;The method of the application is simple, low cost, green and environment-friendly, and the obtained core-shell structure catalyst has high catalytic efficiency, easy recycling and other advantages, and has great application potential in inorganic chemical industry, organic chemical industry, petroleum chemical industry and environmental purification.

The application provides a preparation method of an alumina supported catalyst and application of the alumina supported catalyst in a reaction of partial hydrogenation of benzene to cyclohexene. Benefited from alkali treatment, the surface of the carrier is rich in various charged ions, so that the metal can be uniformly distributed on the surface of the carrier in the loading process, thereby obtaining a highly dispersed Ru-based catalyst. The catalyst involved in the application has a much lower content of metal Ru than a traditional industrial RuZn catalyst, has a more excellent cost advantage, and provides a great economic value for subsequent industrial application.

The present application relates to the technical field of catalyst, in particular to a preparation method of an enhanced industrial catalyst for direct synthesis of alcohol from synthesis gas, the preparation method comprising: impregnating a SiO2 carrier with an impregnation solution to obtain a preliminary catalyst, and then aging, drying and calcining; the preparation method further comprises a structure enhancement treatment of the carrier and / or the preliminary catalyst, the structure enhancement treatment being selected from one or more of steps A and B; the step A comprises subjecting the carrier and / or the preliminary catalyst to superheated steam treatment; the step B comprises subjecting the carrier and / or the preliminary catalyst to hydrothermal reaction in an aqueous sol solution, the sol comprising one or more of a silicon sol, an aluminum sol and a zirconium sol. The preparation method greatly improves the mechanical strength of the catalyst under the premise of maintaining high activity of the catalyst through the structure enhancement treatment, and focuses on solving the requirement of the industrial catalyst for the mechanical strength of the catalyst.

The present application belongs to the technical field of industrial catalyst recovery, and particularly relates to a regeneration method of deactivated DMC catalyst based on mechanical chemical method, regenerated DMC catalyst and application. The method comprises the following steps: pretreatment cleaning: mixing the deactivated DMC catalyst with a polar organic solvent, ultrasonic treatment, removing surface organic residues, and centrifugal drying; mechanical chemical activation: mixing the pretreated catalyst with a metal salt and a complexing agent, and performing high-energy ball milling under an inert atmosphere; post-treatment drying: washing and vacuum drying the ball-milled product to obtain the regenerated DMC catalyst. Through high-energy ball milling, the crystalline phase of the deactivated catalyst is destroyed, and at the same time, the coordination of tert-butyl alcohol and metal salt is utilized to reconstruct the high-activity amorphous structure, thereby avoiding the metal loss and structure collapse caused by traditional acid pickling or high-temperature calcination; zinc salt is dynamically supplemented during the ball milling process, and Co 2+ is oxidized to Co 3+ , so as to restore the complexing ability of the catalyst to the substrate.

The invention relates to the field of industrial catalysts, in particular to a propylene ammoxidation catalyst and a preparation method and application thereof. The propylene ammoxidation catalyst comprises a carrier and active components, wherein the active components comprise Mo, Bi, at least one alkaline earth metal element, at least one alkali metal element and at least one group VIII metal element in the fourth period; in a hydrogen temperature programmed reduction H2-TPR test, the catalyst starts to have a reduction peak in a range of 350-390 DEG C; the reduction rate is 4 * 10 <-4 > a.u. / DEG C to 8 * 10 <-4 > a.u. / DEG C within the range of 420 DEG C to 450 DEG C. The propylene ammoxidation catalyst has a low reduction temperature and a fast reduction rate in hydrogen temperature programmed reduction H2-TPR characterization, and has good reaction activity and long-term stability when being used for preparing acrylonitrile through propylene ammoxidation.

This disclosure provides an in-situ kinetic monitoring device and method for SCR denitrification catalyst poisoning. Through an innovative device integrating a high-precision simulated flue gas generation system, a four-dimensional synchronous monitoring unit, and a data synchronous acquisition and control system, it achieves continuous, in-situ, and multi-parameter coordinated dynamic monitoring and data acquisition of the SCR denitrification catalyst poisoning process under complex operating conditions that highly simulate real industrial flue gas. It achieves the technical effect of fully revealing the coupled poisoning mechanism, constructing a multi-parameter quantitative poisoning kinetic model, and accurately predicting the remaining catalyst life based on this model. This solves the problems of fragmented data, distorted operating conditions, and only qualitative description in existing technologies, providing key technical and data support for the scientific maintenance, replacement timing optimization, and cost reduction of industrial catalysts.

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.

The invention relates to a method for efficiently enhancing low-carbon synthesis of melamine from urea by using a mesoporous Beta molecular sieve, and belongs to the technical field of chemical synthesis. The mesoporous Beta molecular sieve is prepared by a method of alkali post-treatment and addition of a protective agent, and is used for enhancing low-carbon synthesis of melamine from urea. The introduction of the mesoporous structure can improve the mass transfer diffusion of molecules, reduce the generation and accumulation of carbon deposits in the pores of the catalyst, and improve the contactability and utilization rate of active sites in the pores; the product selectivity can be improved by properly adjusting the size and distribution of mesopores, side reactions are inhibited, and the catalytic performance and the catalytic stability are further improved. Compared with the existing industrial catalyst for synthesizing melamine from urea, the Beta molecular sieve provided by the invention shows better melamine yield and cycle stability, the reaction conditions are milder, the catalyst is easy to separate from the product, and the catalyst can be recycled, so that the method is a melamine synthesis method with great application potential.

This invention relates to a method for preparing flower-like hexagonal boron nitride nanopowder, comprising the following steps: S1, mixing a boron-containing matrix salt with a solvent salt to obtain a mixed salt; S2, heating the mixed salt to a molten state and reaching a target temperature, i.e., molten salt; S3, introducing a nitrogen-containing gaseous precursor into the molten salt, allowing the gaseous precursor bubbles to react and nucleate with the boron source in the molten salt, ultimately growing into hexagonal boron nitride nanoflower-like clusters with a three-dimensional structure in the molten liquid phase, i.e., flower-like hexagonal boron nitride nanopowder. The flower-like hexagonal boron nitride nanopowder prepared by this invention has a high specific surface area and a unique three-dimensional isotropic structure, showing great application potential in cutting-edge fields such as high-power electronic packaging thermal interface materials (e.g., thermally conductive silicone grease, thermally conductive pads), high-frequency insulating thermally conductive fillers for 5G / 6G communication substrates, and high-temperature resistant industrial catalyst carriers.