26results about How to "Reduce nitrogen content" patented technology

The invention belongs to the field of flexible peak regulation and carbon reduction of thermal power generating units, and discloses a power station boiler oxygen-enriched hydrogen-ammonia-doped system and a working method thereof.The power station boiler oxygen-enriched hydrogen-ammonia-doped system comprises a boiler, and two combustors on the lower portion of the boiler are micro-hydrogen combustors; a combustion outlet of the micro-hydrogen combustor is connected with a lower hearth of the boiler, the hydrogen main gun is obliquely inserted into the inner side of a pulverized coal air chamber of the micro-hydrogen combustor, the hydrogen ignition gun is located in the middle of the pulverized coal air chamber of the micro-hydrogen combustor, and the hydrogen main gun and the hydrogen ignition gun are both connected with the hydrogen supply system. The boiler is provided with secondary air nozzles above and below each burner, the secondary air nozzle below the lowermost micro-hydrogen burner is arranged as a lower secondary air nozzle, the secondary air nozzle above the lowermost micro-hydrogen burner is arranged as an ammonia-doped secondary air nozzle, and the secondary air nozzle below the lowermost micro-hydrogen burner is arranged as an ammonia-doped secondary air nozzle. The secondary air nozzles above and below the uppermost micro-hydrogen burner are ammonia-doped secondary air nozzles, and ammonia gas inlets of the ammonia-doped secondary air nozzles are connected with an ammonia supply system. The problem of unstable combustion under low load can be solved by combining hydrogen-doped ammonia combustion and air oxygen-enriched combustion supporting.

The invention relates to the technical field of waste treatment, in particular to a kitchen waste treatment method, a carbon source and application thereof. The kitchen waste treatment method comprises the following steps: performing directional fermentation treatment on kitchen waste in an acid environment to obtain a fermentation mixture; filtering the fermentation mixture to obtain filtrate; the filtrate is sequentially subjected to distillation treatment and condensation treatment, volatile organic compounds are collected, and condensate containing volatile fatty acid and low-molecular alcohol is obtained. According to the kitchen waste treatment method, directional fermentation treatment is carried out, and a fermentation mixture is rich in volatile organic compounds including volatile fatty acids (VFAs) such as propionic acid, butyric acid and acetic acid and low-molecular alcohols such as propyl alcohol and ethyl alcohol. And carrying out filtration treatment to reduce the nitrogen content and the suspended matter value in the filtrate. After distillation treatment, the small-molecular organic matters in the filtrate are evaporated, less water is evaporated, and the nitrogen-containing components in the filtrate are almost not evaporated. And the prepared condensate is high in COD value, high in content of micromolecular organic matters and extremely low in nitrogen content.

The invention relates to the technical field of oily wastewater treatment, and discloses a kitchen oily wastewater treatment process based on demulsifying bacteria, which comprises the following steps: adjusting the pH value of kitchen oily wastewater to 6-9, standing and settling, skimming and collecting scum to obtain pretreated oily wastewater a; mixing the pretreated oily wastewater a with a composite demulsifier, introducing air at the speed of 10-20 mm / s, carrying out air flotation treatment for 45-55 minutes, skimming, and collecting suspended matters, so as to obtain pretreated oily wastewater b; and filtering the pretreated oily wastewater b, collecting filtrate and precipitates, and recovering, detecting and reusing the filtrate. The composite demulsifier can improve the stability of the strain in the kitchen oily wastewater and improve the treatment efficiency of the kitchen oily wastewater, and after the composite demulsifier absorbs water, swells and breaks, the modified nano carbon black can be combined with the modified carboxymethyl cellulose through static electricity, so that the composite demulsifier can be used for treating the kitchen oily wastewater. The adsorbed modified carboxymethyl cellulose is flocculated and settled along with the modified nano carbon black, and is removed through filtration.

The invention discloses a normal-pressure smelting and casting process for Ti-containing stainless steel, which comprises the following specific process flows: step A, feeding designed raw materials into an intermediate frequency furnace for steel melting; the raw materials in the step B enter an AOD furnace for degassing, deslagging and refining to purify molten steel after being molten; step C, transferring into an intermediate frequency furnace, adding composite slag to make high-alkalinity reducing slag, and covering the molten steel surface with the high-alkalinity reducing slag; d, after the white slag is kept stable, TiFe starts to be added; e, steel tapping is prepared; f, tapping is started after the components are adjusted to reach the standard; g, blowing argon in the whole tapping process, adding a final deoxidizer for final deoxidation protection, and quickly transferring the steel slag into a steel ladle; and H, product casting molding is conducted. Compared with the prior art, argon blowing is adopted in the whole process to isolate outside air, refining is conducted through the AOD furnace, the content of N and the content of S in the molten steel are reduced through argon blowing and oxygen blowing, and a stable reducing slag system is established to cover the molten steel surface in the whole process so as to protect the surface of the molten steel from being oxidized.

The present invention relates to a system and method for electron beam and oxygen coordinated desulfurization and denitrification, the system comprising a dust removal device, a spray device, a mixed reaction device, an absorption device, an oxygen supply device and an ammonia supply device; the mixed reaction device comprises at least two gas distribution tube plates sequentially arranged inside a shell along the flue gas flow direction and an electron beam generating device after the last gas distribution tube plate; the flue gas flows through the dust removal device, the spray device, the mixed reaction device and the absorption device in sequence; an ammonia inlet is arranged between the flue gas inlet of the mixed reaction device and the first gas distribution tube plate, and the ammonia inlet is connected to the ammonia supply device; an oxygen inlet is arranged between the first gas distribution tube plate and the last gas distribution tube plate, and the oxygen inlet is connected to the oxygen supply device. The system can reduce ammonia emissions, which is beneficial to improving the desulfurization and denitrification effects of flue gas and reducing the impact of purified gas on the environment.

The invention discloses a process method for selective deep desulfurization and denitrification of aromatic-rich fractions. The process method comprises the following steps: (1) mixing aromatic-rich diesel oil with hydrogen, and then feeding the mixture into a pre-hydrogenation reaction zone I for pre-hydrogenation dealkene reaction; (2) a product obtained in the step (1) enters a hydrofining reaction zone II for a hydrofining desulfurization and denitrification reaction; (3) carrying out flash evaporation on the product obtained in the step (2) to separate recycle hydrogen, enabling the obtained refined diesel oil to enter a moving bed adsorption denitrification reaction zone III, and carrying out deep adsorption denitrification reaction on the refined diesel oil under the action of an adsorption denitrification agent to obtain a desulfurized and denitrified refined aromatic-rich diesel oil component; and (4) enabling the inactivated adsorption denitrification agent in the step (3) to enter an adsorbent regeneration area IV, and completing reduction and drying of the inactivated adsorption denitrification agent under the action of a desorption agent to obtain the cyclically regenerated adsorption denitrification agent. According to the process method, deep removal of the sulfur-containing nitrogen-containing compound can be realized, and the investment cost is also greatly reduced.

The application discloses a planting method for improving tobacco quality, and the fertilization mode of the planting method is set as T3, or T4, or T5. The fertilization treatment is beneficial to tobacco plant growth, tobacco carbon and nitrogen metabolism, tobacco leaf quality, and improves tobacco leaf yield.

This invention discloses a method for controlling the nitrogen content of molten steel in a converter with low iron consumption mode, belonging to the field of steel manufacturing technology. The method includes the following steps: controlling the molten iron inlet temperature to 1310-1330℃, controlling the silicon content in the molten iron to 0.30%-0.50%, controlling the molten iron charging ratio to 65-70%, and the scrap steel charging ratio to 30-35%; controlling the converter iron-to-steel ratio to 720-750 kg / t; after adding scrap steel into the furnace, shaking the furnace back and forth until the furnace mouth flame is normal, and baking the scrap steel; adding 50% of the slag in the first 4 minutes of the converter blowing process, and then adding the remaining slag in small amounts multiple times over 4-8 minutes, controlling the furnace temperature, and stirring the molten pool back and forth from high to low with an oxygen lance before the end point; using nitrogen-argon switching bottom blowing during the converter blowing process; adding ladle slag modifier before tapping, and then adding deoxidizer for alloying, while simultaneously performing ladle bottom blowing with argon. The control method of the present invention can control the nitrogen content of converter steel to within 40 ppm under the condition that the iron-to-steel ratio in the converter is as low as 720-750 kg / t.

The invention relates to a miniature turbine power generation system suitable for high altitude and low oxygen content. The miniature turbine power generation system comprises an oxygen generation system, a gas compressor, a heat regenerator, a combustion chamber, a turbine and a power generator. The oxygen generation system separates oxygen-enriched gas from outside air, after the oxygen-enriched gas enters the shell, the oxygen-enriched gas is pressurized through the compressor, the pressure in the shell is increased, a bearing, a main shaft and a motor are cooled, and then the oxygen-enriched gas enters the compressor impeller to be compressed to form high-pressure oxygen-enriched gas; the heat regenerator is connected with high-pressure oxygen-enriched gas at an outlet of the gas compressor and tail gas at an outlet of the turbine, the high-pressure oxygen-enriched gas is heated through tail gas waste heat and then enters the combustion chamber, and high-temperature and high-pressure gas formed after combustion in the combustion chamber enters the turbine and then acts to generate electricity outwards. The problems that a miniature turbine power generation system is difficult to ignite, poor in operation stability and low in power generation efficiency under the high-altitude low-oxygen-content environment are solved, and the system has the advantages of being wide in operation range, stable in low-voltage ignition, reliable in operation, high in power generation efficiency and the like.

The invention relates to the technical field of batteries, in particular to a graphite composite material and a preparation method and application thereof. The graphite composite material comprises a base material layer and a coating layer, and the coating layer comprises a first material layer and a second material layer; the base material layer comprises graphite; the first material layer comprises an amorphous carbon material, and the amorphous carbon material is doped with a first nitrogen element; the second material layer comprises a graphite material, and the graphite material has a porous structure and is doped with a second nitrogen element; the concentration of the first nitrogen element is greater than that of the second nitrogen element. According to the graphite composite material, the first material layer can ensure the reversible capacity and the rate capability of the material; the graphitization degree of the carbon material in the second material layer is high, the irreversible capacity can be reduced, the low nitrogen concentration is beneficial to improving the conductivity, and the porous structure can shorten an ion diffusion channel, so that the energy storage capacity and the rate capability are improved.

A sealing device for a converter oxygen lance insertion hole belongs to the technical field of converter top-blowing equipment and is used for preventing smoke from escaping from the converter smelting top-blowing oxygen lance insertion hole. According to the technical scheme, an insertion hole connecting flange is welded to the periphery of the upper end of an oxygen lance insertion hole, a sealing seat is a circular ring, the circular ring periphery of the sealing seat is connected with the insertion hole connecting flange through bolts, a circular ring inner hole of the sealing seat is conical, and the conical lower end of the circular ring inner hole of the sealing seat is matched with the diameter of the upper end of the oxygen lance insertion hole. The oxygen lance body is sleeved with the sealing plug, the periphery of a circular ring of the sealing plug is conical, the periphery of the sealing plug is connected with an inner hole of the sealing seat in a matched mode, the guide cylinder is a cylinder, the lower end of the guide cylinder is welded to the upper end face of the sealing plug, and the guide cylinder is sleeved with the gas collecting cover which is a cylinder. The lower end of the gas collecting cover is welded to the outer edge of the upper end of the sealing seat. A nitrogen sealing structure is omitted, the oxygen lance insertion hole can be sealed, and smokeless operation is achieved.

The invention discloses a method for producing clean fuel by utilizing sludge based on piezoelectric catalysis assisted hydrothermal carbonization, and particularly relates to a method for preparing a piezoelectric catalyst with a strong piezoelectric effect by adopting a hydrothermal synthesis method and a heterostructure. The method comprises the following steps: mixing sludge with deionized water, and adding a piezoelectric catalyst for piezoelectric catalysis pretreatment; and then carrying out hydrothermal carbonization reaction on the pretreated sludge at 180-240 DEG C, and carrying out solid-liquid separation after the reaction to obtain clean hydrothermal carbon. The piezoelectric catalyst adopts a Bi2WO6 (at) SnS2 heterojunction structure, and under the action of an ultrasonic machine, free radicals are generated, extracellular polymeric substances and cell structures in sludge are destroyed, nitrogen-containing substances are released, a Maillard reaction is inhibited, and generation of nitric oxide is reduced. According to the invention, the nitrogen content in the hydrothermal carbon is reduced, the resource utilization of the sludge and the production of low-nitrogen clean fuel are realized, and the method has the advantages of improving the energy efficiency, reducing the operation cost and reducing the environmental pollution.

The present application provides a harmful waste gas treatment system and a treatment process thereof, and relates to the field of harmful waste gas treatment. It includes: combustion chamber one, combustion chamber two, precooler, washing tower, bag dust collector and main chimney, combustion chamber one is connected to combustion chamber two through an induced draft fan, the precooler is connected to combustion chamber two, the washing tower is connected to the precooler, the bag dust collector is connected to the washing tower, the bag dust collector is connected to the main chimney, combustion chamber one and combustion chamber two are both connected to a spare chimney, and a steel plate is provided on the top of the spare chimney, the outer sleeve of the spare chimney is provided with a support frame, and the support frame is supported on the ground, and an opening and closing assembly is provided between the steel plate and the spare chimney. The present application has the effect of not easily threatening the life and property safety of the staff.

The invention provides a method for controlling the nitrogen content in the oriented silicon steel smelting process, and relates to the technical field of ferrous metallurgy. Ferro-silicon nitride is added twice in the vacuum treatment stage of RH refining to adjust the nitrogen content of molten steel; the addition amount of the silicon iron nitride for the second time is calculated based on the addition amount of the silicon nitride added for the first time, the increase amount of the nitrogen content in the molten steel after the silicon nitride is added for the first time and the target increase amount of the nitrogen content in the molten steel after the silicon nitride is added for the second time through a preset calculation model; the addition amount of the silicon iron nitride for the second time is obtained on the basis of the yield of the nitrogen element after the silicon nitride is added for the first time in the same furnace, so that the influence of the difference of various process parameters of different furnaces on the yield of the nitrogen element is avoided; the difference between the content of the nitrogen element in the RH refining outbound molten steel and the target nitrogen content of the RH refining outbound molten steel is small, and accurate control over the content of the nitrogen element in the RH refining outbound molten steel is achieved.

The carbon dioxide top and bottom blowing system comprises a liquid carbon dioxide storage tank, a heater, a buffer tank, a top blowing pipeline and a bottom blowing pipeline, a liquid carbon dioxide outlet end at the bottom of the carbon dioxide storage tank is connected to a feeding hole of the buffer tank through a pipeline; and the heater is arranged on a pipeline between the liquid carbon dioxide outlet end at the bottom of the carbon dioxide storage tank and the buffer tank. According to the system, carbon dioxide can react with carbon in molten steel, so that the carbon content is reduced, the consumption of oxygen is reduced, the production cost is reduced, and compared with argon, the carbon dioxide is generally cheaper, so that the production cost can be reduced by using the carbon dioxide; in addition, the carbon dioxide can react with sulfur in the molten steel to generate compounds such as calcium sulfide, so that the sulfur content in the steel is reduced, the quality of the steel is improved, and the nitrogen content in the molten steel can be reduced and the quality of the steel can be improved because the carbon dioxide does not contain nitrogen.

The utility model relates to the technical field of lithium battery production, in particular to an NMP (N-Methyl Pyrrolidone) recovery system for cleaning waste liquid of lithium battery positive electrode slurry mixing equipment, which comprises a slurry recovery unit, a waste liquid recovery unit, a waste liquid recovery unit, a waste liquid recovery unit and a waste liquid recovery unit, and is characterized in that the slurry recovery unit is used for separating a positive electrode material and NMP-containing waste water from positive electrode slurry mixing cleaning waste water; the extraction unit is used for enabling an extraction agent to be in contact with the NMP-containing wastewater to obtain NMP-containing extraction liquid; and the rectification unit is used for rectifying and separating the NMP-containing extraction liquid into an extraction agent and NMP. The extraction unit provided by the utility model can effectively remove NMP content in wastewater, reduce COD and total nitrogen content in water, and create conditions for back-end wastewater biochemical treatment. The rectification unit can effectively separate the extraction agent and NMP, the purity of NMP is larger than 99.8%, economic benefits can be improved, and the extraction agent can return to the extraction unit to be reused.

The invention discloses a composite microbial preparation and application thereof in treatment of mariculture wastewater, and relates to the technical field of microbial agents. According to the preparation method, bacillus velezensis, halobacillus dakamoyi and Starproteia are used as fermentation strains, fermentation is performed to obtain a fermentation bacterial liquid, and then gamma-polyglutamic acid, sodium alginate and calcium chloride are utilized to perform immobilization treatment on the fermentation bacterial liquid to prepare the compound microbial preparation. The prepared composite microbial preparation is added into the mariculture wastewater, so that the total nitrogen content, the total phosphorus content and the COD content in a water body can be effectively reduced, the efficient treatment of the mariculture wastewater is realized, and the water quality stability is improved. Wherein the bacillus velezensis, the halobacillus dakamoyi and the Starproteinia are combined for use, and a synergistic effect on reducing the removal efficiency of total nitrogen in the mariculture wastewater is achieved.

The invention relates to the technical field of environmental protection and biomass energy, and particularly provides a device and a method for preparing high-quality bio-oil by culturing microalgae from wastewater and pyrolyzing the microalgae, the device comprises a microalgae incubator, a solid-liquid separation device, a water quality detection device, a drying device, a crushing device, a stirring device and a catalytic pyrolysis purification system, an outlet of the microalgae incubator is connected with an inlet of the solid-liquid separation device through a pipeline, a liquid outlet of the solid-liquid separation device is connected with the water quality detection device, a solid outlet of the solid-liquid separation device is connected with an inlet of the drying device, an outlet of the drying device is connected with an inlet of the crushing device, and an outlet of the crushing device is connected with an inlet of the stirring device. An outlet of the stirring equipment is connected with an inlet of the catalytic pyrolysis purification system. The invention aims to reduce the microalgae culture cost, improve the quality of bio-oil and realize resource utilization of wastewater.

The invention discloses a low-protein daily ration for broiler chickens in the later growth period and application of the low-protein daily ration, belongs to the technical field of animal feed preparation, and provides the low-protein daily ration for the broiler chickens in the later growth period. Comprising corn, soybean meal, corn protein powder, wheat flour, mountain flour, soybean oil, calcium hydrophosphate, table salt, choline chloride, broiler trace elements, DL-methionine, L-lysine hydrochloride, broiler vitamins, L-phenylalanine, L-threonine, L-arginine, L-isoleucine, L-tryptophan, L-valine, glycine, phytase, zeolite powder, potassium carbonate and sodium bicarbonate. According to the invention, the daily ration protein level of the broiler chicken at the late fattening stage of 29-42 days is reduced from 20% to 18%, essential amino acids are balanced, the crude protein content in the broiler chicken daily ration can be effectively reduced, and the protein utilization rate of the broiler chicken is improved, so that the nitrogen content in broiler chicken manure is reduced, and the pollution of broiler chicken production to the environment is reduced.

The invention discloses a nitrogen removal agent for low-nitrogen metal manganese ingot production and a preparation method thereof, relates to the technical field of metal material processing, and aims to solve the problems that in the current low-nitrogen metal manganese ingot processing process, the nitrogen content in a metal manganese ingot is increased, and the nitrogen removal effect is poor due to the fact that the low-nitrogen metal manganese ingot and nitrogen in the environment are easily subjected to a combination reaction. The silicon nitride slag remover comprises a reducing agent and a slag remover, the reducing agent reacts with nitrogen in air to generate a new nitride when the liquid manganese water is heated to 1300 DEG C or above, and the slag remover can adsorb silicon nitride on the surface of the manganese water and form a protective film on the surface of the manganese water. According to the nitrogen removal agent and the production process thereof, the nitrogen content in the metal manganese ingot can be remarkably reduced, a dual-action mechanism is adopted, it is ensured that the nitrogen content of the metal manganese ingot is effectively controlled in the whole production process, and therefore the quality of the metal manganese ingot is improved; therefore, the requirements on low-nitrogen metal manganese ingots in the industries of steel, nonferrous metals and the like can be better met.

The present application relates to a kind of catalytic cracking coke production rich CO gas method, which comprises: the catalyst to be sent into first regenerator and pure oxygen and circulating CO2 contact is carried out first regeneration, and first regeneration flue gas is obtained semi-regenerated catalyst;The mass flow ratio of pure oxygen and circulating CO2 is 0.5~5.0;The semi-regenerated catalyst is sent into second regenerator from the first regenerator and air contact is carried out second regeneration, and regenerated catalyst and second regeneration flue gas are obtained;CO content in the first regeneration flue gas is higher than 35% by volume.The present application does not affect the performance of catalyst and the condition that second regenerator is still completely regenerated, by the catalyst to be sent into first regenerator and pure oxygen and circulating CO2 contact is carried out first regeneration, for replacing the catalyst to be sent into first regenerator and air contact is carried out first regeneration, can increase the CO content in first regeneration flue gas, while reducing nitrogen content.

The application discloses a kind of gas magnetization energy-saving devices, it is related to magnetization energy-saving device technical field, the gas magnetization energy-saving device, including magnetization equipment body, magnetization equipment body includes front shell, rear shell and gas flow pipe, front shell and rear shell are set in front and back two sides of gas flow pipe, the outer surface of front shell and rear shell is fixedly connected with mounting block, the outer surface of gas flow pipe is fixedly connected with two symmetrical first fixed blocks, the top of gas flow pipe is provided with gas pipe, the gas magnetization energy-saving device, by making gear drive fixed rod slide out the inside of fixed groove, so that the fixation of gas flow pipe and gas pipe is removed, so that the connection of gas flow pipe and gas pipe is more convenient, and staff can more smoothly install and disassemble magnetization equipment body, so that staff can conveniently carry out post-maintenance to magnetization equipment body, simultaneously, staff can more conveniently use device.

The invention provides a method for preparing low-protein natural rubber through enzyme compounding, and belongs to the technical field of preparation of low-protein natural rubber products. When the low-protein natural rubber is prepared, pancreatin and trypsin are matched according to the mass ratio of 1: 1, and when the dosage is 0.2 wt%, the protein content of a sample is the lowest. The low-protein natural rubber prepared by the process is superior to acid-coagulated natural rubber in tensile strength, aging property, Mooney viscosity and the like. Compared with the use of the traditional single protease, the use of the compound protease is obviously better than the use of the single protease, and the nitrogen content in the natural rubber can be reduced to about 0.086%; compared with a centrifugal method for preparing the low-protein natural rubber, the technology provided by the invention is simple in process, convenient to operate and more suitable for large-scale production while achieving an ideal effect.

The application relates to a continuous solvent-free reaction synthesis method of cycloxazidone, and belongs to the technical field of organic synthesis. The method comprises the following steps: taking ethyl chloroformate and monocyane as raw materials to generate N-cyano ethyl carbamate; dimethyl sulfate is added to generate N-cyano-N-methyl ethyl carbamate; dimethylamine hydrochloride aqueous solution is added to generate ethyl N-methyl-N-(N', N'-dimethylformamidino) carbamate; cyclohexyl isocyanate is added to generate ethyl N-methyl-N-[(cyclohexyl carbamoyl) (dimethylamino) methylene] carbamate; and the ethyl N-methyl-N-[(cyclohexyl carbamoyl) (dimethylamino) methylene] carbamate is subjected to a cyclization reaction to generate cycloxazidone. The method avoids the large use of toxic and harmful solvents such as chloroform, and the wastewater after the reaction basically does not contain dimethylamine, and the COD and total nitrogen content are greatly reduced.

The utility model relates to the technical field of magnesium oxide manufacturing, in particular to a calcining furnace for preparing magnesium oxide. The calcining furnace comprises a bottom frame, a combustion chamber is fixedly connected to the surface of the bottom frame, a furnace body is arranged in the combustion chamber, one end of the furnace body is fixedly connected with a main shaft, and the other end of the main shaft is fixedly connected with a feeding port. The main shaft and the feeding port are rotationally connected to a bearing seat of the bottom frame, a nitrogen tank is arranged on the side, close to the main shaft, of the bottom frame, and an electromagnetic valve is fixedly installed at the output end of the nitrogen tank. By opening the electromagnetic valve, the nitrogen tank outputs nitrogen to the air inlet head through the air inlet pipe, and the air inlet head outputs the nitrogen into the furnace body through the main shaft, so that the content of the nitrogen in the furnace body is reduced, oxidation reaction of magnesium oxide in the calcining process is avoided, the purity of the magnesium oxide is guaranteed, and the final quality of a product is further guaranteed.

This invention provides a method for extracting and purifying long-chain dicarboxylic acids from fermentation broth, comprising the following steps: 1) Solid-liquid separation: performing a first solid-liquid separation on the long-chain dicarboxylic acid fermentation broth to obtain insoluble matter 1 and filtrate 1; 2) Slurry conditioning and dehydration: conditioning the insoluble matter 1 with a short-chain organic acid and performing a second solid-liquid separation to displace the water in the insoluble matter 1, obtaining insoluble matter 2 and filtrate 2; 3) High-temperature dissolution: dissolving the insoluble matter 2 with a short-chain organic acid at 80-85°C to obtain a solution; 4) Ceramic membrane filtration: filtering the solution through a ceramic membrane at 80-85°C and collecting the permeate; 5) Purification: purifying the permeate to obtain the long-chain dicarboxylic acid product. The method of this invention has advantages such as thorough protein removal, product purity exceeding 98.5%, low total nitrogen content, white color, and fully meeting the requirements of polymerization-grade products.