4925 results about "Crystallization" patented technology

The invention relates to the technical field of chemical automation control, and discloses an intelligent closed-loop control system for producing p-dichlorobenzene by a biomass method, which comprises a signal acquisition module, a residence time reconstruction module, a thermal coupling analysis module, a parameter self-adaptive scheduling module and an execution control module. The rheological characteristics of raw materials are monitored by collecting the current of a stirring motor, the liquid level is dynamically increased through a retention time reconstruction module to prolong the retention time of the materials, and a liquid level periodic migration strategy is introduced to prevent scaling of a gas-liquid interface; the thermal coupling analysis module and the parameter self-adaptive scheduling module are used for calculating thermal retardation post factors, temperature control parameters are corrected in real time, the upper limit of cooling output is limited, inner wall supercooling crystallization is prevented, and the problems that the conversion rate is reduced, the heat transfer efficiency is reduced and equipment is hung on the wall due to viscosity fluctuation of biomass raw materials are effectively solved. And the self-adaptive stable control of the reaction process is realized.

The invention discloses a process and equipment for synthesizing fluorapatite from wastewater, the equipment comprises a blending tank, a dispensing tank, a crystallization fluidized bed reactor, a reaction tank, a coagulation tank, a flocculation tank, a sedimentation tank, a pH detection device, a lift pump and a control system, fluorine-containing sewage and phosphorus-containing sewage are mixed in the blending tank, so that the molar ratio of fluorine to phosphorus is 0.34-0.4; the method comprises the following steps: adding fluorapatite into a reaction tank, adjusting the pH value to 7.5-8.5, pumping the fluorapatite and lime slurry into a crystallization fluidized bed reactor according to a calcium-phosphorus molar ratio of (3-3.5): 1, carrying out a crystallization reaction, naturally airing the generated fluorapatite crystals, carrying out a reaction on crystallization treatment water and the lime slurry in the reaction tank to remove fluorine and phosphorus, carrying out coagulation, flocculation and precipitation treatment, and discharging the effluent after reaching the standard. The high-quality fluorapatite product is prepared from the fluorine-containing sewage and the phosphorus-containing sewage, so that the preparation cost is low, and resourceful treatment of the fluorine-containing sewage and the phosphorus-containing sewage is realized.

The invention discloses a rapid tubular induced crystallization reaction process and device for fluorine-containing wastewater, the device comprises a tubular reactor, a crystal sedimentation tank and crystal dehydration equipment, the fluorine-containing wastewater is pumped from a water inlet at one end of the tubular reactor, calcium liquid is pumped from dosing ports at intervals on the tubular reactor along the flowing direction of the wastewater at a set flow rate, and the calcium liquid is pumped from the dosing ports at intervals along the flowing direction of the wastewater; the fluorine-containing wastewater reacts with a calcium agent in the tubular reactor to generate calcium fluoride crystals with the particle size range of 10-80 microns, a mixture is discharged into a crystal sedimentation tank through a water outlet in the other end of the tubular reactor, clear water is discharged from a water outlet in the upper portion of the crystal sedimentation tank, and crystal slurry sinking to the bottom of the crystal sedimentation tank is pumped into a cyclone separator through a crystal discharging pump; large-particle crystals discharged from an outlet in the lower end of the cyclone separator are collected by a crystal collection pool and are regularly discharged into crystal dehydration equipment for dehydration, small-particle crystals discharged from an outlet in the upper end of the cyclone separator flow back to the water inlet end of the tubular reactor, the reactor is small in size and low in investment, and the stability of the calcium fluoride crystal product quality is guaranteed.

The invention relates to the technical field of material polishing, and discloses a PEEK material composite polishing method and system based on multi-process collaboration.The method comprises the steps that surface detection is conducted on a PEEK material, and crystallinity gradient distribution information is obtained; according to the crystallinity gradient distribution information, process parameter calculation is conducted on the crystalline area and the amorphous area, and a polishing process parameter combination is obtained; inputting the polishing process parameter combination into multi-process collaborative composite polishing equipment, and carrying out gradient interface strengthening polishing on the PEEK material to obtain an interface strengthening polishing semi-finished product; and dynamically adjusting the process parameters of the semi-finished interface strengthening and polishing product to obtain the finished interface strengthening and polishing product, so that accurate division of a crystallization area and an amorphous area of the PEEK material and differential process parameter calculation are realized, and the composite polishing precision of the PEEK material is improved.

The utility model discloses a jacket heat preservation flame arrester for high-oxygen VOCs (volatile organic compounds) to enter dry quenching, which belongs to the technical field of flame arresters and comprises two valve bodies respectively communicated with a gas pipeline for the VOCs to enter the dry quenching and a flame arresting screen arranged between the two valve bodies, a jacket capable of introducing steam to preserve heat is arranged between the two valve bodies, and the two valve bodies are communicated with a gas pipeline for the VOCs to enter the dry quenching. The jacket is arranged on the outer side of the fire-retardant screen; a jacket inlet communicated with a steam pipeline is formed in one side of the jacket, and a jacket outlet communicated with a drain pipeline is formed in the other side of the jacket. According to the utility model, the temperature around the fire-retardant screen can be ensured not to be lower than the crystallization temperature of naphthalene gas, so that the naphthalene gas in VOCs gas can smoothly pass through the fire arrester and then enters dry quenching for incineration, and the VOCs are really discharged without external emission.

The invention discloses a printing and dyeing wastewater zero-discharge treatment process based on low-pressure high-power membrane concentration and salt separation synergy. The wastewater is sequentially subjected to the steps of double-alkali softening pretreatment, organic pollutant treatment, forward osmosis low-pressure high-power concentration treatment, salt separation treatment and evaporative crystallization. Wherein the forward osmosis low-pressure high-power concentration treatment is performed in a partitioned manner along the flow direction, the osmotic pressure difference is gradually increased, the transmembrane pressure difference is gradually decreased, and interface electrochemical buffer and low-frequency gas-liquid disturbance can be set to inhibit concentration polarization and pollution. Carrying out nanofiltration and salt separation on the concentrated solution to obtain two paths of saline water mainly comprising Na2SO4 and NaCl, and respectively carrying out evaporative crystallization on the two paths of saline water; and refluxing and reusing the water produced by the draw solution. According to the process, high-power concentration and stable salt separation are realized under low mechanical pressure, the energy consumption is reduced, the water recovery rate and the crystal purity are improved, and zero discharge of wastewater is realized.

The invention discloses a vibration type drain pipe crystal removal device, and particularly relates to the technical field of pipeline crystal removal, the vibration type drain pipe crystal removal device comprises a cylindrical main machine and a guide climbing frame, one end of the cylindrical main machine is in bolted connection with a propeller, and one end of the cylindrical main machine is provided with a crystal cleaning assembly used for layering and disintegrating crystals in a pipe; the crystal cleaning assembly comprises a conical guide frame and a driven guide ring frame which are movably connected to one end of the cylindrical main machine; a plurality of driving vibration rods and a plurality of driven vibration rods are respectively arranged outside the conical guide frame and the driven guide ring frame; according to the device, crystals in a pipeline are knocked in advance through the driving vibration rod and the driven vibration rod, the knocking target of the driving vibration rod and the driven vibration rod is a crystallization layer instead of a pipe wall, impact force is absorbed by the crystallization layer and does not directly act on a pipe wall body, and after the crystals are knocked to be loose, planing can be completed by the scraping tooth disc without applying too large force; and the scraping tooth disc further planes the fragments into fine chippings, so that the pipeline crystal removal efficiency is improved.

The invention discloses an efficient purification method of rBHET, and belongs to the technical field of waste polyester recycling. A reaction raw material obtained after premixing of waste PET polyester raw material particles and a catalyst and ethylene glycol are jointly and continuously introduced into a depolymerization reactor, the reaction raw material and ethylene glycol in the depolymerization reactor are mixed and pass through a plurality of rotating discs, and the materials form a flowing film on the rotating discs rotating at a high speed to promote depolymerization; depolymerization reaction liquid generated in the depolymerization reactor enters a temporary storage tank to be stored after being subjected to impurity removal, the depolymerization reaction liquid in the storage tank is introduced into a rectifying tower to be primarily concentrated and purified, obtained concentrated liquid enters an evaporator to be secondarily concentrated and purified, obtained secondary concentrated liquid enters a cooler to be cooled and then enters a product tank to be crystallized; and drying the crystallized solid to obtain a high-purity rBHET product. According to the method, the production efficiency is improved, and the purity of rBHET is effectively improved.

The invention relates to the field of fine chemical engineering, and discloses a green process for preparing chloramine T by a continuous flow reactor. The method comprises the following steps: respectively pumping p-toluenesulfonamide, a sodium hydroxide solution and a sodium hypochlorite solution into a micro-channel mixer for instantaneous mixing, and carrying out chlorination reaction in a multi-stage temperature control tubular reaction unit; the concentration of free chlorine is detected on line at an outlet, and the flow rate of a chlorine source is dynamically adjusted through a PID algorithm, so that closed-loop control is realized; the reaction liquid is directly crystallized and separated to obtain the product without alkali wash. The system comprises a base solution and chlorine source conveying subsystem, a micro-channel mixer, a multi-stage reaction unit, an online monitoring module, a central controller and a crystallization unit. The side reaction is inhibited from the source, so that the free chlorine is less than or equal to 0.5 mg / L, the alkali washing step is omitted, the COD (Chemical Oxygen Demand) of the wastewater is reduced by more than 80%, the product purity is more than or equal to 99.5%, and the productivity is improved by 3 times.

The invention discloses a jet type micro-droplet generation device and a micro-droplet generation method thereof, and belongs to the technical field of liquid-liquid heterogeneous / homogeneous reaction devices. The device comprises an injection pipe, the injection pipe is used for conveying a first liquid phase, the interior of the injection pipe is of a cavity structure, the injection pipe comprises a feeding section, a mixing section, a diffusion section and a feeding pipe, the feeding section, the mixing section and the diffusion section are sequentially communicated and coaxially arranged, the feeding pipe is used for conveying a second liquid phase, and the feeding pipe penetrates through the side wall of the feeding section and extends into an inner cavity of the injection pipe; a discharging opening of the feeding pipe is formed in the mixing section, and an annular flowing space is formed by the outer wall of the feeding pipe and the inner wall of the mixing section. The feeding pipe extends into the mixing section to form an annular flowing space, and a second liquid phase is dispersed into small liquid drops by fully utilizing the annular space and a strong shear flow field in the mixing section. The method is suitable for a liquid-liquid heterogeneous / homogeneous system, including a liquid-liquid heterogeneous / homogeneous reaction crystallization system generated by solid particles.

The invention discloses an artemisinin extraction intelligent tracking and identification method, and relates to the technical field of image data processing. According to the method, an integrated closed-loop system is constructed through cooperation of four core technical means: based on classified filtering of foam stability difference and bimodal adaptive segmentation, dynamic foam is accurately removed, and preliminary interface extraction is optimized; the attention enhancement U-Net network is embedded into a channel attention module and an edge enhancement branch to realize accurate positioning and fluctuation tracking of a layered interface; the attention mechanism dynamically adjusts the bimodal weight, and completes multi-index cooperative tracking in combination with a partitioning strategy and an improved network; a crystal growth model is introduced to correct particle weight, a tracking effect is optimized by adopting layered resampling, and a closed-loop feedback mechanism of a crystal state and process parameters is established. All technical means are deeply coordinated, intelligent and accurate management and control of the whole extraction process are achieved, and reliable technical support is provided for artemisinin extraction production.

The invention relates to the technical field of molten salt, in particular to nitro binary molten salt and a preparation method thereof. The preparation method comprises the following steps: mixing sodium carbonate and a potassium hydroxide solution, and then adding a starch-based grafted crystal inhibitor to inhibit crystallization; adding a nitric acid aqueous solution in two stages, and introducing eutectic seed crystals to guide nucleation at the end of the first stage; crystal distribution is optimized through falling film evaporation and concentration and setting of partial reflux; and after spraying granulation, carrying out short-time melting reforming and controlled cooling in an inert atmosphere. According to the method, the composition uniformity and the structural stability of the molten salt are remarkably improved, so that the product has a melting point close to a theoretical eutectic point, low supercooling degree, high melting latent heat and excellent thermal cycling stability and corrosion resistance, and is suitable for an industrial heat storage system running for a long time.

The invention relates to the technical field of molten salt treatment, and discloses a molten salt recovery system based on a steel belt cooling granulator. The system comprises a molten salt physical property monitoring module, a viscosity modeling module, a cooling optimization module, a partition temperature control module, a phase change monitoring module, a dynamic adjustment module, a particle size analysis module, a quality grading module, a pneumatic conveying module and a waste heat recovery module. The progressive crystallization control of the molten salt particles is realized; a heat pipe type heat exchanger and an organic Rankine cycle system are integrated at the waste heat recovery end, so that comprehensive energy consumption is reduced; the environment regulation and control end monitors the workshop temperature and humidity in real time based on a dew point calculation model, and the long-term stability of hygroscopic fused salt particles is guaranteed. According to the method, four technical bottlenecks of out-of-control crystallization, energy waste, classification loss and environmental interference in fused salt recovery are overcome, and low-cost, high-purity and zero-waste fused salt resource recycling is realized.

The invention relates to the technical field of fine chemical engineering and flame retardant preparation, and discloses a preparation method of bromo-triazine capable of improving thermal stability, and the preparation method comprises the following steps: mixing phenol, water and dichloromethane, controlling the temperature, and carrying out oxidative bromination reaction to prepare an organic phase containing tribromophenol; then, under the action of an organic amine catalyst, carrying out condensation reaction on the organic phase, liquid caustic soda and cyanuric chloride; after the reaction, washing with water to remove impurities; and in the presence of process water, firstly controlling the temperature at 38-42 DEG C for azeotropic desolvation, then raising the temperature to 85-95 DEG C for high-temperature crystallization and crystal growing, and finally cooling, filtering and drying to obtain the bromo-triazine product. By utilizing the high selectivity of the organic amine catalyst and a two-stage azeotropic crystallization process, the side reaction is effectively reduced, the solvent wrapped in the crystal is eliminated, the prepared product is high in main content and extremely low in volatile component, the temperature can reach 370 DEG C or above when the thermal weight loss is 2%, and the thermal stability is remarkably improved.

The invention relates to the technical field of nitrate production, in particular to a potassium nitrate purification device which comprises a dissolving tank, a filtering device, a crystallization kettle, a centrifugal machine and a drying machine with a steam jacket which are sequentially connected in series through pipelines. The dissolving tank first jacket is connected with a heat source through a circulating pipeline; a liquid outlet of the centrifugal machine is sequentially connected with the cyclone separator, the ceramic membrane filter, the cationic resin column, the first temporary storage tank and the heat source, and the first heat exchanger and the second heat exchanger are sequentially installed between the first temporary storage tank and a heating medium inlet of the heat source. A steam outlet pipeline of the steam jacket is connected with a heat medium inlet of the first heat exchanger, the first heat exchanger is connected with the second temporary storage tank through a pipeline, and the second temporary storage tank is connected with the heat source through a pipeline. A pipeline of the second vacuum unit is connected with a thermal medium inlet of a second heat exchanger, and the second heat exchanger is connected with a second temporary storage tank. According to the method, the potassium nitrate purification efficiency, the product purity, the resource utilization rate and the energy economy are synergistically improved.

The invention discloses a preparation process of a concrete self-healing crystallization additive, and belongs to the technical field of building materials, and the preparation process comprises the following steps: respectively grinding 30-60 parts of refined silica powder and 20-40 parts of quartz sand, then adding 30-60 parts of refined silica powder and 20-40 parts of quartz sand into a mixing barrel in a dryer, then adding 8-20 parts of silicate, and drying for 3-5 minutes; then taking out the mixing barrel and putting into a mixing machine for mixing; sequentially adding 1-3 parts of an alkali metal salt compound into the mixture in the step 1 every 5-10 minutes, mixing for 5-10 minutes, and adding for 4 times in total; 2, 2-4 parts of a functional auxiliary agent is added into the mixture obtained in the step 2, mixing is conducted again for 10-15 min, standing is conducted for 50-80 min after mixing is completed, and the self-healing crystallization additive is obtained; according to the invention, the added silicate and alkali metal salt compound is dissolved in mixed concrete under the action of contacting with water and permeates in pores and microcracks of the concrete along with the water, so that the body impermeability and compactness of the concrete are improved.

The invention provides a cooling rate optimization control method and system for continuous cooling crystallization, and the method comprises the steps: collecting crystal slurry concentration data and temperature data of each stage of crystallization tank in real time; the crystal slurry concentration data, the temperature data and the feeding flow data are input into a deep learning model, and a prediction result is obtained; based on the prediction result and crystal mush concentration data, dynamically adjusting the cooling rate of each stage of crystallizing tank and the addition amount of a co-crystallizing solvent; and feeding back an outlet crystal mush concentration signal of the last-stage crystallizing tank to the solid-liquid separation unit, and adjusting the running rotating speed of the solid-liquid separation unit in a linkage manner. According to the cooling rate optimization control method and system for continuous cooling crystallization, prospective correction of the cooling rate is carried out by using the predicted supersaturation degree, and adjustment of the additive amount of the auxiliary crystallization solvent is carried out by using the predicted crystal particle size distribution; and finally, an outlet concentration signal of the last-stage crystallizing tank is fed back to the solid-liquid separation unit in real time to adjust the separation rotating speed in a linkage manner, so that the crystal particle size deviation is reduced, and the triazole crystallization recovery rate is improved.

The invention belongs to the field of functional material preparation, and relates to an MOFs crystal film and a preparation method and application thereof. According to the MOFs crystal film, a porous polymer supporting film is used as a carrier, a high-crystallinity, compact and continuous rigid MOFs crystal layer grows on the surface of the porous polymer supporting film in situ, and a solid / quasi-solid electrolyte system is formed by matching polymer electrolyte or electrolyte. The MOFs ordered pore channel ion screening effect and metal ion sites are used for limiting anions, so that the ion transference number is increased; a physical-chemical synergistic dendritic crystal inhibiting mechanism is realized by utilizing high mechanical strength and a high crystal structure; the low-tortuosity compact ordered MOFs crystal film is used for improving the conductivity, the MOFs electrolyte with wide temperature range stability and high voltage resistance is obtained, and a support is provided for realizing a secondary battery with high energy density and high safety.

The embodiment of the invention provides an evaporation system control method and an evaporation system, and relates to the technical field of control, the method is applied to a control system in an MVR evaporation system.The method comprises the steps that in response to a starting instruction, a feeding system is controlled to pump to-be-treated liquid into an evaporation crystallization system, and the real-time boiling point rise of the evaporation crystallization system is monitored; and determining to adopt an optimal recovery rate control mode or a boiling point rise control mode as a target control mode based on the real-time boiling point rise, and controlling the feeding system, the evaporative crystallization system and the water production system to treat the to-be-treated liquid according to a preset strategy corresponding to the target control mode, the frequency of the distilled water and the flow of the to-be-treated liquid pumped by the feeding system meet the corresponding recovery rate, so that the control intelligence and reliability of the MVR evaporation system are improved.

The invention discloses a preparation method of 5N specified-grade high-purity vanadium pentoxide, which comprises the following steps: step S1, taking high-purity ammonium metavanadate as a raw material, mixing the raw material with pure water in proportion, heating for dissolving, and cooling to obtain an ammonium metavanadate solution; s2, enabling the ammonium metavanadate solution to pass through a resin column for adsorption, and collecting column passing liquid; s3, carrying out vacuum concentration on the column passing liquid, cooling and crystallizing the obtained concentrated liquid, and carrying out suction filtration to obtain primary crystals; s4, mixing the primary crystal with pure water in proportion, heating, filtering, cooling filtrate, crystallizing, filtering and washing with water to obtain a secondary crystal; step S5, repeating crystallization operation for 1-3 times to obtain recrystallized ammonium metavanadate; and step S6, putting ammonium metavanadate into a porcelain baking tray, putting the porcelain baking tray into a calcining furnace, vacuumizing, calcining and cooling to obtain a 5N specified-grade high-purity vanadium pentoxide product. The method has the characteristics of simple principle, convenience in operation, high reliability and the like, and the purity of vanadium pentoxide is remarkably improved.

The invention relates to the technical field of continuous casting crystallizers, and discloses a detachable multi-stage water-cooling crystallizer structure and application thereof in copper column continuous casting, the detachable multi-stage water-cooling crystallizer structure comprises a cooling system and a crystallization pipe, the cooling system is used for cooling the crystallization pipe, the crystallization pipe comprises a plurality of crystallization plates, and the crystallization plates are arranged in the crystallization pipe. The crystallization pipe is formed by mutually splicing a plurality of crystallization plates in the direction around the axis of the crystallizer and the axial direction of the crystallizer, and the crystallization plates can move in the axial direction, so that replacement of the crystallization plates is realized; the cooling system comprises cooling pipes, the pipe walls of the cooling pipes are tightly attached to the outer pipe walls of the crystallization pipes, the crystallization plates correspond to one or more sets of cooling pipes, and the cooling system has the advantages that in the continuous casting production process, partition replacement of crystallizer copper plates can be achieved, the production cost of copper column continuous casting is reduced, and the production efficiency is improved.

The invention relates to the technical field of reaction kettles.The reaction kettle comprises a kettle body, a protective cover is fixedly connected to the top of the kettle body, a feeding opening is formed in the top of the kettle body in a penetrating mode, a supporting plate is fixedly connected to the bottom of the interior of the kettle body, and stirring shafts are rotationally connected to the interiors of the supporting plate, the kettle body and the protective cover; the stirring shaft is located at the center of the kettle body, the surface of the stirring shaft is fixedly connected with three stirring blades, the three stirring blades are distributed in a linear array from top to bottom, and the bottom of the stirring shaft is fixedly connected with a paddle. Through the heterogeneous sensing network constructed by the multi-parameter sensing subsystem, synchronous monitoring of multi-dimensional physical quantities such as discharge port pressure, stirring torque and kettle wall vibration is realized, the limitation of traditional single parameter monitoring is broken through, and the early recognition precision and reliability of the crystallization blockage risk are greatly improved.

The invention discloses a perovskite precursor solution additive, a perovskite light absorption layer and a preparation method of the perovskite light absorption layer. The preparation method of the perovskite solar cell comprises the following steps: adding a mixed solution of deionized water containing hydrochloric acid or organic amine hydrochloride and DMF (Dimethyl Formamide) into a perovskite solution to form a perovskite precursor solution, further obtaining a perovskite light absorption layer through a film preparation process, and assembling the solar cell. The crystallization process of the thin film is adjusted through chloride ions, hydroxyl and amino in the aqueous solution of hydrochloric acid or organic amine hydrochloride, decomposition of formamidine iodide is inhibited, growth of crystal grains is promoted, the quality of the thin film is improved, pinhole and grain boundary defects are reduced, and therefore the device performance of a perovskite photovoltaic cell prepared in air is enhanced.

The invention discloses a grading reaction crystallization recovery process and system for semiconductor fluorine-containing and phosphorus-containing waste liquid, the fluorine-containing and phosphorus-containing waste liquid and a lime solution react in a fluorine recovery crystallization reactor under the condition that the pH is 3-4 to form calcium fluoride crystals, and the calcium fluoride crystals are dehydrated to obtain calcium fluoride particle crystal products; the effluent of the fluorine recovery crystallization reactor, the calcium fluoride crystal dehydration filtrate, the lime solution and the calcium chloride solution react in a secondary reaction tank under the condition that the pH is 5-6, and calcium fluoride, fluorapatite, silicon dioxide and silicon-aluminum precipitates are removed through coagulation, flocculation and precipitation; effluent of the second-stage reaction tank, the lime solution and the calcium chloride solution react in the phosphorus recovery crystallization reactor under the condition that the pH is 7-8 to generate hydroxyapatite crystals, and the hydroxyapatite crystals are dehydrated to obtain hydroxyl calcium phosphate particle crystal products. Meanwhile, a high-purity calcium fluoride crystal product and a hydroxyl calcium phosphate crystal product are produced, and fluorine and phosphorus are recycled.

This invention discloses a method for preparing high-purity zirconium oxide, belonging to the field of compound preparation technology. The method provides a breakthrough adjustment of the final concentration state and the cooling process after concentration and evaporation of an acidic zirconium oxychloride solution under the action of an oxidant. Simultaneously, crystallization is achieved through a two-stage concentration and evaporation process, followed by calcination to obtain hafnium-free zirconium oxide. The resulting zirconium oxide not only has a high yield but also high purity. Furthermore, the technical solution of this invention avoids the generation of ammonia nitrogen wastewater as in existing technologies, thus not only avoiding environmental impact but also significantly reducing production costs through the recycling of hydrochloric acid condensation, achieving a green and environmentally friendly effect.

The invention discloses a preparation method of a nylon 66 salt crystal, which is characterized in that in the method, a nylon 66 salt aqueous solution is subjected to secondary crystallization and a rotary pressure filter process to prepare the nylon 66 salt crystal. According to the technology, the problems of low single-stage yield and large sewage discharge amount are solved by adopting secondary crystallization and evaporation condensate recycling, and the processes of centrifugation, drying, cyclone separation and the like are reduced by replacing a centrifugal machine with a rotary pressure filter, so that the energy consumption per ton of products is reduced.

This invention relates to the field of special agents for treating air pollution, specifically to a rare earth water-based environmentally friendly urea crystal remover for vehicles and its preparation method. The raw materials for preparing the rare earth water-based environmentally friendly urea crystal remover for vehicles, by weight, include: 0.005-0.2 parts rare earth-based catalyst, 3-10 parts surfactant, 1-3 parts dispersant, 5-10 parts stabilizer, and 80-100 parts deionized water; wherein the rare earth-based catalyst includes at least a cerium-based catalyst. The urea crystal remover provided by this invention has excellent performance, effectively removing urea crystals, and the cerium emission concentration is far below the requirements of the EURO 7 draft (EURO 7 does not require cerium). NOx conversion rate is significantly improved, making it more suitable for vehicles using high-sulfur fuels, and greatly benefiting the control of air pollution from mobile sources. It is also environmentally safe and environmentally friendly.

The invention belongs to the technical field of impurity separation, and particularly discloses a method for separating and purifying impurities in a process for preparing glyoxylic acid through oxalic acid electrolysis, a crystallization kettle is included, an isolation device is arranged in the crystallization kettle, and the isolation device comprises a conical top cover, a conveying pipe, an annular filter screen, a directional conveying assembly and a sealing assembly; the conical top cover is arranged at the axis of the crystallization kettle, an opening of the conical top cover faces downwards, and a plurality of fixing rods are fixedly connected between the top of the conical top cover and the inner wall of the side face of the crystallization kettle. According to the method, glyoxylic acid product solutions with different concentration specifications and the high-purity glyoxylic acid crystal can be obtained after the electrolyte is sequentially subjected to pre-evaporation, electrodialysis, secondary evaporation, cooling crystallization, solid-liquid separation, washing and drying and other procedures, so that the prepared high-purity glyoxylic acid crystal can be popularized and applied in the field of high-end medicine.

The invention belongs to the technical field of polyether refining, and particularly relates to a methyl-terminated polyether refining treatment method. Comprising the following steps: adding water into a to-be-refined methyl-terminated polyether sample, stirring, dissolving salt in water, layering, adding water into a polyether layer again after separation, stirring, layering, and separating to obtain a primary sample; taking a methyl-terminated polyether sample to be refined again, heating, adding water, adjusting the pH with acid, and stirring to obtain a sample A; adding the preliminary sample into the sample A, and stirring to obtain a sample B; and adding acid into the sample B to adjust the pH value, continuously stirring, crystallizing the metal salt into large particles, settling, separating out solids, deacidifying and decolorizing, dehydrating in vacuum, and filtering to obtain qualified methyl-terminated polyether products, and intercepting part of qualified products as preliminary samples for continuous production. By adding the methyl-terminated polyether primary finished product, the crystallization process of the metal salt can be effectively improved, so that the metal salt tends to generate coarse particles easy to filter, the filtering resistance is reduced, and the filtering period is shortened.

The invention belongs to the technical field of magnesium desulfurization wastewater treatment, and particularly relates to a magnesium desulfurization wastewater ammonia nitrogen and heavy metal ion cooperative treatment system which is characterized by comprising a vertical flow sedimentation tank, a stirring reaction device and a cyclone separator, and an outlet of the vertical flow sedimentation tank is connected with an inlet of the cyclone separator through a material transfer pipeline; a bottom outlet of the cyclone separator is connected with a stirring reaction device, the stirring reaction device is connected with an inlet of the vertical flow sedimentation tank through a seed crystal pump and a seed crystal pipeline, the stirring reaction device is connected with an automatic phosphate dosing feeder, the bottom of the stirring reaction device is connected with a blow-off pipeline through an automatic blow-off valve, and the treated desulfurization wastewater enters a downstream sewage treatment plant or is subjected to slag flushing. The method has the advantages that denitrification efficiency is high, reaction is stable, ammonia nitrogen and heavy metal ions in the magnesium desulfurization wastewater are synergistically removed, separated magnesium ammonium phosphate (struvite) precipitate crystals are used as seed crystals to return and adsorb, excessive addition of phosphate agents is reduced, and the effect of mixed reaction can be guaranteed.