31results about How to "Shorten crystallization time" patented technology

The invention relates to the technical field of fan shell materials, in particular to an antibacterial PP (polypropylene) fan shell material and a preparation method thereof. The polypropylene composite material is prepared from the following components in parts by weight: 80 to 90 parts of polypropylene composite material, 1 to 3 parts of polyethylene glycol grafted maleic anhydride, 1 to 5 parts of modified lignin, 8 to 15 parts of nano modified montmorillonite, 1 to 4 parts of silver nitrate, 1 to 3 parts of coupling agent KH550, 0.1 to 0.5 part of calcium stearate and 0.3 to 0.6 part of antioxidant, through double modification of lignin and three-step modification of montmorillonite, the dispersity and interface bonding strength of the filler are remarkably improved, the tensile strength of the material is improved by 37% or above, and meanwhile good toughness is kept; a multi-component synergistic system realizes the persistence of the antibacterial performance, and the antibacterial efficiency of 95% or above is still kept after 7 days. Thirdly, through the synergistic effect of the modified lignin and the nano-montmorillonite, the thermal stability of the material is remarkably improved, and the initial degradation temperature is increased by 20-35 DEG C.

The invention discloses a method for synthesizing a CHA molecular sieve from coal gangue, and belongs to the technical field of coal chemical materials. The method comprises the following steps: S1, mixing a silicon source, an aluminum source, a template agent I and water to obtain mixed gel I; s2, heating and crystallizing the mixed gel I in the step S1 under a closed condition to obtain a high-activity crystal nucleus II; s3, mixing the high-activity crystal nucleus II in the step S2 with coal gangue, water, a template agent II and an alkali metal source to obtain gel III; s4, heating and pre-crystallizing the gel III in the step S3 under a closed condition to obtain a pre-crystallized product I; and S5, heating and crystallizing the product I in the step S4 under a closed condition to obtain the CHA powder sieve material. According to the method for synthesizing the CHA molecular sieve from the coal gangue, disclosed by the invention, the CHA molecular sieve product can be rapidly synthesized at high yield by using the low-activity coal gangue as a raw material under the condition of low template agent dosage.

The invention relates to the technical field of preparation of Beta molecular sieves, and discloses a method for rapidly preparing a nano Beta molecular sieve by using a microwave synthesis method, which comprises the following steps: selecting proper silicon sources (such as silicon dioxide, white carbon black and the like) and aluminum sources (such as sodium metaaluminate, aluminum sulfate and the like), adding a template agent (such as tetraethylammonium hydroxide), an alkali source (such as sodium hydroxide) and deionized water, and carrying out microwave synthesis to obtain the nano Beta molecular sieve. Uniformly mixing and stirring according to a specific molar ratio to obtain initial gel; and crystallizing the gel, wherein a conventional hydrothermal method or a microwave heating method can be adopted. And after crystallization is completed, carrying out post-treatment such as filtration, washing, drying and high-temperature calcination on the product to finally obtain the Beta molecular sieve product. According to the method for rapidly preparing the nano Beta molecular sieve by utilizing the microwave synthesis method, provided by the invention, the synthesis steps are simplified, the crystallization time is remarkably shortened, the production efficiency is improved, the particle size of the nano Beta molecular sieve is effectively controlled, and a nano-scale product with smaller particle size and more uniform distribution is obtained.

The invention relates to the field of preparation of molecular sieves, and discloses a preparation method of an all-silicon molecular sieve with an MFI topology structure, the all-silicon molecular sieve with the MFI topology structure and application of the all-silicon molecular sieve with the MFI topology structure, the method comprises the following steps: (1) mixing molecular sieve mother liquor, organic silicate ester, an organic template agent and alcohol to obtain a colloid mixture; the mass ratio of SiO2 in the molecular sieve mother liquor to the organic silicate ester based on SiO2 is (0.01-0.2): 1; the molar ratio of the alcohol to SiO2 in the molecular sieve mother liquor is (10-100): 1; (2) carrying out crystallization reaction on the colloid mixture; (3) carrying out solid-liquid separation on the crystallization product obtained in the step (2) to obtain a molecular sieve wet material and crystallization mother liquor; drying and roasting the molecular sieve wet material; and (4) optionally concentrating the crystallized mother liquor, and then returning to the step (1). The preparation method can effectively utilize the molecular sieve mother liquor, saves the cost, is beneficial to environmental protection, and is easy to operate.

The invention discloses a method for preparing functional sugar through ultrasonic-assisted co-crystallization, which comprises the following steps: heating a molasses raw material in a sugar boiling tank, continuously stirring to obtain a cane sugar supersaturated solution, maintaining the temperature of syrup to be lower than 120 DEG C, and monitoring the brix of the syrup in real time; when the brix of the syrup reaches 68-72 degrees Bx, transferring the syrup into a glass dish, cooling to 70 DEG C, and adding the camellia nitidissima leaf polyphenol extract, arabinose and camellia nitidissima micro powder into the syrup in a powder form; transferring the syrup into an ultrasonic water bath kettle, carrying out ultrasonic treatment at 25-35 DEG C, and continuously and mechanically stirring until solid substances appear; and transferring the obtained solid substance into a metal disc, and drying in a vacuum drying oven at 63-67 DEG C for 22-24 hours.

The invention belongs to the technical field of anhydrous magnesium chloride production, and particularly relates to a preparation process of anhydrous magnesium chloride, which comprises the following steps: firstly, dissolving magnesium chloride hexahydrate in absolute ethyl alcohol to form a magnesium chloride ethanol aqueous solution, and then dehydrating the magnesium chloride ethanol aqueous solution by using a molecular sieve to obtain the magnesium chloride ethanol solution; carrying out secondary cooling, stirring crystallization, secondary solid-liquid separation and vacuum drying on the magnesium chloride ethanol solution to obtain high-purity anhydrous magnesium chloride; and recycling ethanol liquid obtained by solid-liquid separation and ethanol gas obtained by vacuum drying. The technical scheme provided by the invention is simple in process flow, low in energy consumption, low in equipment requirement, high in product yield and high in purity, and can be directly applied to the fields of electrolytic preparation of magnesium, catalyst carriers and the like.

The application relates to the field of carbon nanotube catalyst materials, and specifically discloses a catalyst and a preparation method thereof, an array type carbon nanotube and a preparation method thereof. A catalyst is formed into a sheet-shaped nanocrystalline grain, and the sheet-shaped nanocrystalline grain comprises at least one kind of microwave active metal ion. The preparation method of the catalyst comprises the following steps: S1, microwave-assisted reaction; S2, standing and aging; and S3, calcination treatment. An array type carbon nanotube is prepared by catalysis of the catalyst, the array type carbon nanotube has a plurality of unit carbon nanotube bundles, the unit carbon nanotube bundle comprises a plurality of carbon nanotubes which are intertwined and have a tube length greater than 1 mu m, and the tube diameter of the unit carbon nanotube bundle is 0.2-2 mu m. The carbon nanotube prepared by catalysis of the catalyst has a consistent length-diameter ratio, good orientation and high purity, so that the excellent performance of the carbon nanotube can be brought into play.

The invention relates to the field of organic synthesis, in particular to a preparation method of a process for preparing high-purity citric anhydride. The preparation method comprises the following steps: preparation of a hierarchical pore zeolite molecular sieve, preparation of a supported molecular sieve catalyst and synthesis of the high-purity citric anhydride. According to the method, the zeolite molecular sieve is subjected to alkalization treatment, so that the connectivity of pore channels of the zeolite molecular sieve can be improved, the catalytic effect can be improved, and high-purity citric anhydride can be synthesized in an assisted manner; by preparing and using the supported molecular sieve catalyst, the generation of a citric acid dehydration reaction is facilitated, the generation of byproducts is reduced, and the catalytic efficiency and the catalytic performance are improved; in the process of synthesizing the high-purity lemon anhydride, the separated crystalline solid is washed by using the oxygen-containing organic solvent, so that the purity of the lemon anhydride can be improved.

The present invention discloses a ZSM-23 zeolite and a process for preparing the same and use thereof. The total acid amount of said ZSM-23 zeolite is 0.05-0.25 mmol / g, preferably, 0.06-0.22 mmol / g, more preferably, 0.06-0.20 mmol / g; the strong acid content of said ZSM-23 zeolite is 5-33%, preferably, 7-33%, more preferably, 9-33%, or further preferably, 7-31%, further more preferably, 10-28% of the total acid amount; wherein the strong acid refers to an acid having a desorption temperature of 350°C or higher in an NH3 temperature programmed desorption (NH3-TPD). The ZSM-23 zeolite has a low strong acid content, and the preparation process of the ZSM-23 zeolite is simple.

The invention relates to the field of crystallizer equipment, and discloses double-layer crystallizer equipment which comprises a support, treatment barrels are fixedly connected to the left side and the right side of the interior of the support, and multiple layers of stirring mechanisms are arranged in the treatment barrels; the multi-layer stirring mechanism comprises a supporting plate, a two-way motor, two sleeves and four fixing plates, the left side and the right side of the supporting plate are fixedly connected to the inner side walls of the two treatment barrels, and the bottom wall of the two-way motor is fixedly connected to the top wall of the supporting plate. According to the invention, through the arrangement of a multi-layer stirring mechanism, the problems that crystals have relatively large difference in granularity and form, are easy to accumulate and block and influence normal operation of equipment can be solved, and two first rotating rods rotate and penetrate through the inner space of the treatment barrel, so that the crystallization time is effectively shortened, the production efficiency is improved, and the production cost is reduced. The contact opportunity between the medicament and the crystal is increased, so that the formation of a crystal nucleus is accelerated.

The invention discloses a method for recovering D-psicose crystals from syrup, belongs to the technical field of D-psicose crystallization, and optimizes the crystallization process parameters of D-psicose by using SAS company's JMP software for experimental design (design of experiment, DOE), deeply analyzes the influence of crystallization process parameters on crystallization yield, and establishes a crystallization yield prediction model, thereby accurately controlling the crystallization process. The crystallization yield of D-psicose according to the present invention is increased from 81%% to 91.36% (the highest crystallization rate published by existing data); and the obtained D-psicose crystals are uniform in size, smooth in surface, and have a relatively regular long rod shape with high quality; at the same time, the method also establishes a prediction model for crystallization rate, which can provide guidance for crystallization parameter control in subsequent large-scale production.

The invention provides a nafamostat mesylate new crystal form and a preparation method thereof, and belongs to the technical field of medicine crystal forms. An X-ray diffraction pattern of the new crystal form of nafamostat mesylate has characteristic diffraction peaks at the following 2 theta angles: 10.56 degrees, 12.02 degrees, 14.97 degrees, 15.95 degrees, 16.27 degrees, 16.95 degrees, 17.68 degrees, 18.35 degrees, 18.71 degrees, 19.22 degrees, 19.78 degrees, 20.42 degrees, 20.84 degrees, 21.74 degrees, 21.98 degrees, 22.55 degrees, 23.09 degrees, 23.72 degrees, 24.05 degrees, 24.25 degrees, 24.88 degrees, 25.78 degrees, 26.27 degrees, 27.30 degrees, 28.01 degrees, 28.84 degrees, 29.02 degrees, 29.81 degrees, 30.60 degrees, 30.96 degrees, 32.28 degrees, 32.98 degrees, 33.39 degrees, the new crystal form of nafamostat mesylate and the preparation method provided by the invention have the advantages of high purity, good stability, controllable process and easiness in repetition.

The utility model discloses a rapid solid crystallization system which comprises a concentration kettle, a cooling kettle, a first crystallization kettle, a second crystallization kettle and a centrifugal machine, a feeding pipe is connected to the top of the concentration kettle, a steam pipe network is connected to the concentration kettle and is communicated into the concentration kettle, and a vacuum system is connected to the top of the concentration kettle and the top of the cooling kettle. Pipelines connected with the bottoms of the concentration kettle and the cooling kettle are respectively led to the tops of the first crystallization kettle and the second crystallization kettle; a water pipe network is connected to the bottoms of the cooling kettle, the first crystallization kettle and the second crystallization kettle, a pipeline for connecting the bottoms of the first crystallization kettle and the second crystallization kettle leads to the centrifugal machine, and a discharge port of the centrifugal machine is connected with a blanking funnel. According to the utility model, the rapid crystallization of solids can be realized, the crystallization time is shortened by two thirds, the solid yield is improved, and the production cost is reduced.

This invention relates to the field of all-silica molecular sieve preparation technology, and discloses a method for preparing an MFI topological structure all-silica molecular sieve, the MFI topological structure all-silica molecular sieve and its application, comprising: (1) mixing molecular sieve mother liquor, organosilicate, organic template agent and KOH to obtain a colloidal mixture; (2) subjecting the colloidal mixture to a crystallization reaction; (3) performing solid-liquid separation on the crystallization product obtained in step (2) to obtain a wet molecular sieve and a crystallization mother liquor; drying and calcining the wet molecular sieve to obtain an MFI topological structure all-silica molecular sieve; (4) optionally concentrating the crystallization mother liquor, and then returning to step (1) to provide the molecular sieve mother liquor. This method can obtain highly crystallized, fine-particle all-silica-1 molecular sieves, reduce the raw material cost of molecular sieve synthesis, and improve the economics of the new gas-phase rearrangement process technology.

The invention discloses a phase-change emulsion for phase-change temperature-adjusting cellulose fibers and a preparation method of the phase-change temperature-adjusting cellulose fibers. The phase-change emulsion comprises the following components: 20-30 wt% of a phase-change material, 1-3 wt% of a nucleating agent with an antibacterial function, 1-3 wt% of protein colloid particles, 0.3-0.5 wt% of a surfactant and the balance of deionized water. Adding the phase change emulsion into a prepared cellulose solution by adopting a pre-spinning injection method to obtain a phase change spinning solution; the phase-change spinning solution is coagulated and formed through a spinning bath, then enters an air bath to be drafted, and then is cut off, desulfurized, pickled, washed, bleached, oiled and dried to prepare the phase-change temperature-adjusting cellulose fiber. The phase-change emulsion is low in supercooling degree, good in compatibility with a cellulose solution and used for preparing phase-change temperature-adjusting cellulose fibers, the spinnability is good during spinning, the production process is stable, and the fiber strength after spinning forming is high.

The invention discloses a biodegradable agricultural film and a preparation method thereof, and belongs to the technical field of biodegradable agricultural films.The preparation method comprises the steps that a ZIF (at) SiO2 super-hydrophobic high-activity hybrid dispersed with assistance of silicon dioxide is prepared through assistance of ultrasonic microwaves, the ZIF (at) SiO2 super-hydrophobic high-activity hybrid and polydopamine are subjected to ultrasonic dispersion, a polylactic acid film is coated with the ZIF (at) SiO2 super-hydrophobic high-activity hybrid and polydopamine, and a water retention layer is prepared; the multi-layer biodegradable agricultural film with far-infrared warming and water retention properties is prepared by preparing a warming layer from a high-activity infrared absorbent and aliphatic polyester, preparing a high-barrier layer from high-activity nanosheets and PCL (polycaprolactone), and laminating and molding the water retention layer, the warming layer and the high-barrier layer, thereby obtaining the multi-layer biodegradable agricultural film with far-infrared warming and water retention properties. The prepared biodegradable agricultural film not only has the advantages of far infrared heating and water retention, has the effects of increasing the yield and improving the quality of crops, but also has good degradability, is expected to replace a common agricultural film to be popularized and used in a farmland, reduces the pollution of the agricultural film to soil, and accelerates the development of modern ecological agriculture.

This application provides a method for purifying crude dihydroxyethyl terephthalate (BHET), a method for preparing BHET, and a BHET product. The method includes: mixing crude BHET with a solvent to obtain a first mixture; wherein the solvent includes a first solvent and a second solvent; subjecting the first mixture to stepwise cooling, during which the BHET in the first mixture crystallizes to obtain purified BHET. This method optimizes crystallization kinetics, shortens crystallization time, reduces solution viscosity, and thus improves solid-liquid separation performance, ultimately obtaining a high-purity, uniformly sized BHET product.

The invention discloses a high specific surface area nano FAU molecular sieve synthesis method, which comprises: 1) dissolving a silicon source, an aluminum source and an alkali source in water, and uniformly mixing in a premixing device to obtain a mixed solution A; standing and aging to obtain a guiding agent; 2) dissolving an alkali source and an aluminum source in water by taking a silicon source as a single material to obtain a mixed solution B; in premixing equipment, premixing a silicon source and the mixed solution B with the guiding agent prepared in the step 1) to form reaction initial gel; and 3) transferring the initial reaction gel in the premixing equipment into a crystallization kettle for hydrothermal crystallization reaction, taking out a product after the reaction is finished, filtering, washing and drying to obtain the FAU molecular sieve. The particle size of the nanosheet-shaped FAU molecular sieve is 20-450 nm, the specific surface area is 960-1100 m < 2 > / g, and the pore volume of mesopores is 0.1-0.8 cm < 3 > / g; more active sites can be provided, the diffusion path is shorter, and the molecular diffusivity can be improved.

The present invention provides a rare earth-poor two-phase composite magnetic material and a preparation method thereof, belonging to the field of magnetic materials. The structural formula of the rare earth-poor two-phase composite magnetic material is: (RE a Nd 1‑a ) b (Fe 1‑c Co c ) 100‑b‑e‑f‑g‑h (B 1‑d Q d ) e Cu f T g M h ; Among them, RE is a light rare earth element, Q is a main group element, T is a low melting point element, and M is a grain refining element; a , c , d Respectively represent the molar fractions of RE, Co, and Q replacing Nd, Fe, and B elements, satisfying 0≤ a ≤0.2,0≤ c ≤0.05,0≤ d ≤1; b、e、f、g、h Respectively represent the molar fractions of the total content of Nd and light rare earth elements, the total content of B and main group elements, Cu elements, low melting point elements, and grain refining elements, satisfying 4≤ b ≤7, 6≤ e ≤10,0≤ f ≤1,0≤ g ≤1,0≤ h ≤2.

This invention provides a method for producing lubricating oil base oil from heavy feedstock and the resulting lubricating oil base oil. The method includes: cutting the heavy feedstock to obtain a light component, a middle fraction, and a bottom wax; wherein the boiling point ranges of the light component, the middle fraction, and the bottom wax are 170-300℃, 300-500℃, and >500℃, respectively; subjecting the bottom wax to a first isomerization reaction under the catalysis of a first isomerization catalyst to obtain a first isomerization product; subjecting the first isomerization product and the middle fraction to a second isomerization reaction under the catalysis of a second isomerization catalyst to obtain a second isomerization product; subjecting the second isomerization product to hydrorefining; and then fractionating the obtained refined product to obtain the lubricating oil base oil. The lubricating oil base oil produced by this method has high yield, low pour point, low cloud point, and high viscosity index, making it a high-quality lubricating oil base oil.

The invention relates to the field of preparation of pseudo-boehmite, and discloses a method for integrally preparing pseudo-boehmite. The method comprises the following steps: in a pseudo-boehmite preparation device, carrying out carbonization reaction and crystallization on carbon dioxide in industrial flue gas and an alkaline aluminum source solution; the device comprises a closed tank body, an air inlet pipe, a liquid inlet pipe and a temperature controller, the gas inlet pipe is used for introducing industrial flue gas into the closed tank body; the liquid inlet pipe is used for introducing an alkaline aluminum source solution into the closed tank body; the closed tank body is used for carrying out carbonization reaction and crystallization on carbon dioxide and an alkaline aluminum source solution in industrial flue gas to obtain a crystallized product; and the temperature controller is used for regulating and controlling the temperature in the closed tank body. By adopting the method provided by the invention to prepare the pseudo-boehmite, integration of a carbonization reaction unit and a crystallization unit can be realized, so that the impurity crystal content of the prepared pseudo-boehmite is obviously reduced.

The invention provides a ZSM-48 molecular sieve and a preparation method thereof, an isodewaxing catalyst and a preparation method and application thereof, and the preparation method of the ZSM-48 molecular sieve comprises the following steps: uniformly mixing an aluminum source, a silicon source, an alkali source, a crystallization inducer, a template agent, deionized water, a pore-forming agent and a charge balance agent, then sequentially pre-crystallizing the obtained gel solution at 70-90 DEG C for 2-6 hours, filtering, and drying to obtain the ZSM-48 molecular sieve. The preparation method comprises the following steps: dissolving a ZSM-48 molecular sieve into a solvent, crystallizing at 120-140 DEG C for 2-6 hours, crystallizing at 140-170 DEG C for 10-48 hours, washing, drying and roasting a crystallized product, mixing an obtained molecular sieve precursor with ammonium salt, and washing, drying and roasting to obtain the ZSM-48 molecular sieve. The carrier particles of the isodewaxing catalyst comprise a ZSM-48 molecular sieve. Acidic sites of the molecular sieve are uniformly distributed, and the molecular sieve has a small grain size and a high total BET (Brunauer, Emmett and Teller) specific surface area. The isomerization dewaxing catalyst has the advantages of high reaction efficiency, high isomerization conversion rate and low cracking rate.

The invention belongs to the technical field of catalysts and application thereof, and particularly relates to a preparation method and application of a low-cost small-grain TS-1 molecular sieve based on molecular sieve precursor dry glue. According to the method, a TS-1 titanium silicalite molecular sieve precursor dry glue containing an original zeolite unit is used as a seed crystal, and the small-grain TS-1 titanium silicalite molecular sieve with high framework titanium content is synthesized by using cheap raw materials. The grain size of the prepared molecular sieve is less than 200 nanometers, the prepared molecular sieve is a b-axis oriented single crystal, and the titanium content of a tetra-coordinated framework accounts for more than 90% of the total titanium content in percentage by mass. In the initial crystallization stage, the TS-1 titanium silicalite molecular sieve precursor dry glue is dissolved in an alkaline environment and recrystallized to form a large number of zeolite seed crystals, and as the crystallization time is prolonged, silicon-titanium nutrient substances in the cheap raw materials are supplied to the zeolite seed crystals to grow to form the TS-1 titanium silicalite molecular sieve. According to the method, tetrapropylammonium bromide is used for replacing tetrapropylammonium hydroxide to serve as a template agent, and various titanium sources, water glass and other silicon sources are adopted, so that the cost is remarkably reduced.

This invention discloses a solution-based epitaxial growth method for perovskite thin films and its preparation method, belonging to the field of perovskite optoelectronic device technology. Addressing the difficulty of achieving high-quality multilayer structures and crystal orientation control using existing solution methods, this invention first prepares a perovskite template layer with a preferred orientation on a substrate, and then uses thermal shock treatment to induce rapid crystallization of a second precursor solution under the guidance of the template layer's lattice structure. This method utilizes a solvent with inverse temperature solubility (such as 2-methoxyethanol), effectively solving the solvent orthogonality problem and achieving epitaxial growth of perovskite crystals. The resulting thin film exhibits a (001) preferred orientation throughout its thickness direction, with a Herman orientation factor as low as −0.36 and a trap state density as low as 1.62 × 10⁻⁶. 15 cm −3 The perovskite solar cells prepared using this method achieve a photoelectric conversion efficiency of 25.58% and exhibit excellent stability under high temperature and high humidity conditions. This invention features a simple and low-cost process, and is suitable for large-area fabrication and various perovskite material systems.

The invention discloses a molecular sieve crystallization auxiliary agent and a preparation method and application thereof. A two-dimensional image of a crystal in the molecular sieve crystallization auxiliary agent is rectangular, the length size of the crystal is 5.0-18.0 nm, the width size of the crystal is 2.0-6.0 nm, and the ratio of the length to the width is 1.5-3.5. When the molecular sieve crystallization auxiliary agent is added into a conventional formula for synthesizing a molecular sieve, the crystallization time of the molecular sieve can be obviously shortened, and the grain size of the molecular sieve is reduced.

The invention relates to the field of potassium persulfate synthesis, in particular to low-nitrogen high-purity potassium persulfate and a synthesis method thereof. According to the synthesis method of the potassium persulfate, heating and heat preservation are carried out in the synthesis process, after the reaction is finished, the potassium persulfate is cooled to a certain temperature, then the potassium persulfate is rapidly placed in a low-temperature environment to be subjected to a low-temperature crystallization technology, potassium persulfate crystals are obtained, and low-nitrogen and high-purity potassium persulfate can be obtained through subsequent cleaning, centrifugal drying. According to the method, separation of nitrogen-containing impurities and potassium persulfate can be effectively promoted by combining heat-preservation stirring with a freezing crystallization technology, the crystallization time is shortened, and the product has higher crystallinity, so that the production efficiency and the product quality are improved.

The utility model discloses a continuous lactose production crystallizing tank which comprises a tank body, an end cover is connected to the upper end of the tank body, a partition plate is connected to the middle in the tank body, an outer shaft is rotationally connected to the end cover, an inner shaft is rotationally connected into the outer shaft, the lower end of the outer shaft is rotationally connected with the partition plate, and the inner shaft penetrates through the partition plate and extends to the lower portion in the tank body. A driving box is mounted on the end cover; a first driving mechanism for driving the outer shaft to rotate and a second driving mechanism for driving the inner shaft to rotate are arranged in the driving box; the outer shaft is detachably connected with a plurality of turbo-type stirring paddles, and the outer wall of the lower part of the inner shaft is detachably connected with a frame-type stirring paddle; an overflow groove is formed in the partition plate, a plurality of overflow pipes communicated with the overflow groove are connected to the periphery of the bottom of the partition plate, and the inner wall of the overflow groove inclines towards the overflow pipes on the two sides. Through vertical zoning and differential stirring in the tank body, the continuous flow of crystal nucleus generation, growth and ripening is realized in the same tank body, and the crystallization time is shortened.

The utility model discloses a citric acid crystallization reaction kettle, and relates to the technical field of citric acid crystallization reaction kettles, the citric acid crystallization reaction kettle comprises a reaction kettle, a feed pipe and a discharge pipe, the inner surface of the reaction kettle is provided with a stirring mechanism and a heating mechanism, and the heating mechanism is located on the surface of the stirring mechanism; the stirring mechanism comprises a stirring part and a rotating part; the rotating part is positioned below the stirring part. Through the arrangement of the stirring mechanism, the stirring part stirs a solution in the reaction kettle, so that the liquid in the reaction kettle is mixed more uniformly, meanwhile, the inner wall of the reaction kettle is cleaned by a scraper, and waste caused by the fact that citric acid is attached to the inner wall of the reaction kettle after crystallization is avoided; the surface of the reaction kettle is uniformly heated, a solution in the reaction kettle is conveniently and uniformly heated, the solution in the reaction kettle can be stirred again, the crystallization time of citric acid in the reaction kettle is shortened, and the crystallization efficiency of the reaction kettle on the citric acid is improved.

The invention belongs to the technical field of biological fermentation and crystallization separation, discloses a method and a system for producing isomaltulose by coupling double-bacterium synergistic fermentation with gradient temperature control crystallization, and solves the problem that glucose generates feedback inhibition on sucrose isomerase in a fermentation stage. The method comprises a fermentation stage and a crystallization stage, a double-bacterium synergistic fermentation system of recombinant bacillus subtilis engineering bacteria and recombinant pichia pastoris engineering bacteria is adopted in the fermentation stage, and the inoculation ratio of the recombinant bacillus subtilis engineering bacteria to the recombinant pichia pastoris engineering bacteria is 3: 1-5: 1; in the crystallization stage, a gradient temperature control-ultrasonic-assisted coupling crystallization process is adopted, after the fermentation liquor is subjected to concentration pretreatment, the temperature is reduced to 25-28 DEG C at the speed of 0.5-0.8 DEG C / h, and heat preservation and ultrasonic treatment are performed; and cooling to 15-18 DEG C at the speed of 0.3-0.5 DEG C / h, preserving heat and carrying out ultrasonic treatment. The method provided by the invention realizes efficient production and accurate purification of isomaltulose.

This invention relates to the field of catalysts for the gas-phase Beckmann rearrangement reaction of cyclohexanone oxime, and discloses a method for preparing the catalyst and the method for the gas-phase Beckmann rearrangement reaction of cyclohexanone oxime. The method includes: mixing a molecular sieve mother liquor, an organosilicate, an organic template agent, and KOH to obtain a colloidal mixture; subjecting the colloidal mixture to a crystallization reaction; separating the obtained crystallization product into a solid-liquid mixture to obtain a wet molecular sieve and a crystallization mother liquor; drying the wet molecular sieve to obtain a raw molecular sieve powder; optionally mixing the raw molecular sieve powder with a binder, and then rotating it to obtain spherical particles; calcining the spherical particles, and then contacting them with an alkaline buffer solution containing ammonium salt, ammonia, magnesium salt, and bromide salt. This catalyst, when applied in fixed-bed or moving-bed reactions, enables long-cycle, continuous production of caprolactam with a high conversion rate of cyclohexanone oxime.