Long-carbon-chain binary acid large-particle crystal and preparation method thereof
By controlling the acidolysis crystallization process and using centrifugal and boiling drying technology, large-particle long carbon chain dibasic acid crystals are prepared, which solves the problems of high energy consumption and inconvenient transportation in the existing technology, and achieves the effects of energy saving and consumption reduction and easy use.
Patent Information
- Application Number
- CN202410286094.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-13
- Publication Date
- 2025-08-08
AI Technical Summary
The prior art process of producing long-chain dibasic acid has high energy consumption, and powdered products are inconvenient for transportation and use, resulting in an increase in downstream production costs and an increase in environmental protection investment.
Large-particle long carbon chain dibasic acid crystals are prepared by controlling the pH value, temperature, stirring time and cooling rate during acidolysis crystallization, and centrifugation and boiling drying are used to replace traditional plate-frame filtration and flash drying.
It greatly reduces production energy consumption, improves transportation and use convenience, and reduces environmental investment and waste of downstream production.
Smart Images
Figure CN120443348A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the fields of microbiology and its derivatives, biochemical engineering and polymer chemistry, and more specifically to a large-particle crystal of a long-carbon-chain dibasic acid produced by biological fermentation and a preparation method thereof. Background Art
[0002] Long-chain dibasic acids (DCN) refer to aliphatic dibasic acids with more than 10 carbon atoms in their carbon chains, including both saturated and unsaturated long-chain dibasic acids. They are a class of fine chemical products with important and widespread industrial applications. They are typically produced using alkanes as raw materials through fermentation and oxidation by oleophilic bacteria. The content of long-chain dibasic acids in the fermentation broth ranges from 2% to 17%. Extraction and purification of long-chain dibasic acids from the fermentation broth typically involves removing bacteria from the fermentation broth, decolorizing, acid precipitation and crystallization, filtration, and drying. This entire process fully utilizes the water-insolubility of long-chain dibasic acids.
[0003] The existing process flow for producing long-chain dibasic acids is as follows: ① first-level seed tank → ② second-level seed tank → ③ fermentation tank → ④ fermentation liquid storage tank → ⑤ ceramic membrane system → ⑥ activated carbon decolorization system → ⑦ acid precipitation crystallization → ⑧ product plate frame → ⑨ flash drying → ⑩ packaging system, such as Figure 1 As shown. However, in the purification process stage after acid precipitation crystallization, the long carbon chain dicarboxylic acid crystal particles after acid precipitation crystallization by the traditional method are very small, and only the plate and frame filtration method can be used to remove part of the water. The long carbon chain dicarboxylic acid (water content) still contains about 25% water. After that, the flash drying method is used to remove the water. Flash drying requires a large amount of steam to remove the water in the long carbon chain dicarboxylic acid after plate and frame filtration, and then the long carbon chain dicarboxylic acid white powder product is obtained. The entire purification process (excluding the fermentation process) requires 10 tons of steam, 2000 kWh of electricity, and 10 tons of water per ton of finished product, and the production energy consumption is very high. In addition, powdered long carbon chain dicarboxylic acid is not convenient for packaging and transportation, and because the powdered product is prone to dust and electrostatic adsorption, it is not convenient for downstream production and use, which increases the environmental protection investment and raw material waste in downstream production. Each batch of downstream production and use has 3% to 5% feed waste. Summary of the Invention
[0004] In response to the above problems, the present invention provides a method for preparing large-particle crystals of long-chain dibasic acids. This method can prepare large-particle crystals, which not only saves energy and reduces production costs, but also saves downstream costs and improves ease of use.
[0005] The specific technical solutions provided by the present invention are as follows:
[0006] The present invention provides a method for preparing large-particle crystals of a long carbon chain dibasic acid, comprising the following steps:
[0007] The long-chain dicarboxylic acid fermentation broth is sterilized and decolorized in sequence to obtain a solution containing long-chain dicarboxylic acid anions;
[0008] adding acid to the solution containing the long-chain dibasic acid anion to perform acid precipitation crystallization to obtain a long-chain dibasic acid suspension;
[0009] Add dry powdered long-chain dicarboxylic acid to the long-chain dicarboxylic acid suspension, cool the mixture to 25-36°C at a rate of 1-3°C / min, stir the mixture at 120-200 r / min for 3-5 hours, control the pH value to be 3.0-5.0 during the stirring process, and then perform aging crystallization, centrifugation, and drying in sequence to obtain large long-chain dicarboxylic acid crystal particles.
[0010] Preferably, the temperature is lowered to 30-32° C. at a rate of 2-2.5° C. / min, and stirred at 160-180 r / min for 3-4 h, and the pH is controlled at 3.5-4.2 during the stirring process.
[0011] The molecular formula of the long carbon chain dibasic acid of the present invention is: HOOC-(CH2) n -COOH, n is 8 to 20.
[0012] Preferably, the amount of dry powdered long chain dibasic acid added is 5-50% based on the total amount of the long chain dibasic acid suspension and the dry powdered long chain dibasic acid, and the purity of the powdered long chain dibasic acid is 70-99.9%.
[0013] Preferably, the centrifugation is carried out using any one of a turbine centrifuge, a tripod centrifuge, a horizontal spiral centrifuge, a disc centrifuge, a tubular centrifuge, a filter centrifuge or a sedimentation centrifuge; and the drying is carried out using any one of a boiling dryer, a fluidized bed dryer, a spray dryer or a belt dryer.
[0014] Preferably, the centrifugation is performed in a turbine centrifuge, and the water content of the large particles of long carbon chain binary crystals obtained after centrifugation is 3% to 10%; the drying is performed in a boiling dryer, and the water content of the large particles of long carbon chain binary crystals obtained after drying is 0.5% to 2%.
[0015] Preferably, the acid is added to make the pH of the long carbon chain sodium dibasic acid solution be 3.5 to 5.8, and the acid is selected from sulfuric acid or hydrochloric acid.
[0016] Preferably, the acid addition is to add a concentrated sulfuric acid solution with a mass fraction of 93-95% to the long-chain sodium dibasic acid solution.
[0017] Preferably, the acid precipitation crystallization is to raise the temperature of the solution to 93±2° C. after adding acid and maintain the temperature for 1 to 3 hours.
[0018] Preferably, the long carbon chain dibasic acid suspension is a mixed solution of a long carbon chain dibasic acid and water or a mixed solution of a long carbon chain dibasic acid and an organic solvent, and the organic solvent is toluene, xylene, chlorobenzene, dichlorobenzene, nitrobenzene, ethyl acetate, isopropyl acetate, methyl acetate, butyl acetate, octyl acetate, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, ethylene glycol dipentyl ether, ethylene glycol dihexyl ether, ethylene glycol diheptyl ether, ethylene glycol dioctyl ether, ethylene glycol dinonyl ether, ethylene glycol didecyl ether, ethylene glycol dilauryl ether, methyl chloride, acetic acid , propionic acid, butyric acid, malonic acid, succinic acid, adipic acid, terephthalic acid, ethyl ether, propyl ether, amyl ether, hexyl ether, heptyl ether, octyl ether, nonyl ether, decyl ether, lauryl ether, methyl tert-butyl ether, acetone, butanone, methanol, ethanol, butanol, propanol, ethylene glycol, propylene glycol, 1,4-butanediol, tetrahydrofuran, 1,4-dioxane, DMSO, methyl ethyl ether, methyl butyl ether, methyl octyl ether, ethyl ethyl ether, ethyl butyl ether, ethyl octyl ether, anisole, phenethyl ether, phenbutyl ether, phenoctyl ether, and chloroform.
[0019] The present invention also provides a long carbon chain dibasic acid crystal large particle prepared according to the above method, wherein the particle size of the long carbon chain dibasic acid crystal large particle is 10 to 200 mesh and the crystal density is 0.2 to 2 g / cm 3 The purity of single acid is 70% to 99.9%, the purity of total acid is 70% to 99.9%, and the water content is 0.5% to 2%.
[0020] Compared with the prior art, the present invention has the following beneficial effects:
[0021] (1) The preparation method of large-particle crystals of long-chain dibasic acid provided by the present invention improves the bulk density of acid-precipitated crystals of long-chain dibasic acid by regulating the four core production conditions of pH value, temperature, stirring, and time as well as the cooling rate and stirring rate after acid precipitation crystallization. The particle density of long-chain dibasic acid crystals is increased by more than two times. The density of crystalline long-chain dibasic acid is more than three times the density of powdered long-chain dibasic acid, and the volume is less than 1 / 3 of that of powdered long-chain dibasic acid. For example, when powdered long-chain dibasic acid is used, the reactor is fed with 1 ton of material at a time. When large-particle long-chain dibasic acid crystals are used instead, the reactor can be fed with 3 tons of material at a time. The feed ratio of downstream production is increased by at least three times, and the downstream production efficiency is increased by at least two times. At the same time, the large-particle long-chain dibasic acid crystals are easy to pack and transport, thereby reducing the packaging, transportation and use costs.
[0022] (2) The prior art uses a plate and frame filter press to flash dry the powdered product. Because the powdered product easily causes dust and electrostatic adsorption, it is necessary to increase environmental protection investment to prevent and control dust when used in downstream production. At the same time, due to electrostatic adsorption, 3% to 5% of the long carbon chain dibasic acid feed is wasted for each batch of downstream production. The preparation method of large-particle long carbon chain dibasic acid crystals provided by the present invention can prepare large-particle long carbon chain dibasic acid crystals with a size of 10 to 200 mesh, and the particle size can be determined according to the requirements of the solvent used in downstream production, thereby eliminating dust and electrostatic adsorption, reducing downstream production investment, reducing feed waste, reducing downstream production costs, and improving ease of use.
[0023] (3) According to the traditional biological fermentation method for producing long-chain dicarboxylic acids, a plate-and-frame filtration method is used to remove some of the water. The long-chain dicarboxylic acid still contains about 25% water. Then, a flash drying method is used to remove the water. Flash drying requires a large amount of steam and electricity to remove the water in the long-chain dicarboxylic acid after plate-and-frame filtration. Then, a white powder of the long-chain dicarboxylic acid is obtained. The entire purification process (excluding the fermentation process) consumes 10 tons of steam, 2,000 kWh of electricity, and 10 tons of water per ton of finished product, and the production energy consumption is very high. The preparation method of large-particle crystals of long-chain dicarboxylic acid provided by the present invention is to add the same type of powdered long-chain dicarboxylic acid finished product to a concentration crystallization tank, allow the long-chain dicarboxylic acid crystals to precipitate in the form of large-particle crystals through aging, and then use a centrifuge to dehydrate the long-chain dicarboxylic acid crystals to a water content of 3% to 10%. Then, a boiling drying method is used to obtain dry large-particle long-chain dicarboxylic acid crystals, and the water content is reduced to 0.5% to 2%. The improved extraction process only consumes 3 tons of steam, 1,000 kilowatt-hours of electricity, and 6 tons of water per ton of finished product. Steam consumption is reduced by 70%, electricity usage is reduced by 50%, and water usage is reduced by 40%. Production energy consumption is greatly reduced, and the cost per ton is saved by more than 2,000 yuan, which is of great significance to industrial production. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 The figure is a process flow chart for producing long-chain dibasic acids using existing technology.
[0025] Figure 2 This is a flow chart of the process for preparing large-particle crystals of long-chain dibasic acid provided by the present invention.
[0026] Figure 3 Figure 2 is a diagram of the powdered finished product obtained using the prior art (A, dry powder; B, diagram of the adsorption phenomenon of the powdered finished product on the surface of the packaging bag).
[0027] Figure 4 The invention provides large-particle crystals of long carbon chain dibasic acid; A. a mixture of large-particle crystals with a mesh size of 10 to 200; and B. adsorption conditions of the large-particle crystals in a packaging bag. DETAILED DESCRIPTION
[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0029] The present invention provides a method for preparing large-particle crystals of a long carbon chain dibasic acid, such as Figure 2 As shown, the following steps are included:
[0030] The long-chain dicarboxylic acid fermentation broth prepared by the biological fermentation method is treated with a ceramic membrane system and an activated carbon decolorization system to obtain a solution containing long-chain dicarboxylic acid anions. Acid is added for acid precipitation crystallization to obtain a mixed solution of long-chain dicarboxylic acid and water or an organic solvent. The mixed solution is concentrated and crystallized by strictly controlling the cooling rate of 1-3°C / min, the cooling temperature of 25-36°C, the stirring speed of 120-200 r / min, the pH value of 3.0-5.0 (isoelectric point), and the cooling time of 3-5 hours. During the concentration and crystallization, the dried powdered product of the same type of long-chain dicarboxylic acid is added to increase the bulk density of the long-chain dicarboxylic acid crystals. After that, the long-chain dicarboxylic acid crystals are aged and crystallized, separated by centrifugation, and dried in a drying equipment to obtain large particles of 10 to 200 mesh long-chain dicarboxylic acid crystals. The molecular formula of the long-chain dicarboxylic acid is: HOOC-(CH2) n -COOH, n is 8 to 20. The control parameters were obtained by the inventors through a large number of experiments, and the inventors found during the experiments that no long carbon chain dibasic acid crystals could be obtained by adjusting the parameters outside the range described in the present invention, and only powdered long carbon chain dibasic acid could be obtained.
[0031] As a preferred embodiment of the present invention, the control parameters can be adjusted as follows: cooling to 30-32°C at 2-2.5°C / min, stirring at 160-180 r / min for 3-4 hours, and controlling the pH to 3.5-4.2 during stirring.
[0032] In the present invention, the bacterial bodies are generally removed by passing the long-chain dibasic acid fermentation broth through a stainless steel membrane or a ceramic membrane system to intercept the bacterial bodies and obtain a clear liquid; the decolorization step is to add activated carbon to the clear liquid to adsorb large molecular proteins such as pigments; and the acid precipitation crystallization is to precipitate the long-chain dibasic acid in the filtrate through acid adjustment, and the pH value is controlled in the range of 3.5 to 5.8. It is understandable that the acid used for acid adjustment can be sulfuric acid or hydrochloric acid, etc.
[0033] In some preferred embodiments, the weight ratio of the dried powdered product of the same type of long carbon chain dibasic acid added to the concentration crystallization tank is 5% to 50%, and the purity of the powdered product is 70% to 99.9%.
[0034] In some preferred embodiments, the centrifuge is a turbine centrifuge, a tripod centrifuge, a horizontal spiral centrifuge, a disc centrifuge, a tubular centrifuge, a filter centrifuge or a sedimentation centrifuge; the drying equipment is a boiling dryer, a fluidized bed dryer, a spray dryer or a belt dryer.
[0035] The invention uses a centrifuge to dehydrate the large-particle crystals of the long carbon chain dibasic acid obtained through the preparation process, which is convenient, economical and efficient in production practice.
[0036] In some preferred embodiments, the pH value of the concentrated crystallization is controlled between 3.0 and 5.0, and by regulating the isoelectric point, the long carbon chain dibasic acid precipitated by the acid precipitation crystallization is adsorbed on the finished long carbon chain dibasic acid and precipitated as larger crystal particles.
[0037] After concentration and crystallization, the packing density of long carbon chain dibasic acid crystals increases by 2 to 10 times.
[0038] After aging and crystallization, large-particle long-chain dicarboxylic acid crystals are obtained. After centrifugal separation and drying, the density of the large-particle long-chain dicarboxylic acid crystals is between 0.2 and 2.
[0039] After boiling drying, the large particle long carbon chain dibasic acid crystal size is 10 mesh to 200 mesh.
[0040] After aging and crystallization, large-particle long-chain dicarboxylic acid crystals are obtained. After centrifugal separation, the water content of the large-particle long-chain dicarboxylic acid crystals is between 3% and 10%.
[0041] After aging and crystallization, large-particle long-chain dicarboxylic acid crystals are obtained. After centrifugal separation and drying, the large-particle long-chain dicarboxylic acid crystals have a water content between 0.5% and 2%.
[0042] The purity of the large-particle long-carbon-chain dibasic acid crystals is 70% to 99.9% for single acid and 70% to 99.9% for total acid.
[0043] The above-mentioned solution containing long-chain dibasic acid anions can be obtained by biological fermentation or chemical synthesis; the solution containing long-chain dibasic acid anions can be an aqueous solution of long-chain dibasic acid ammonia, long-chain dibasic acid magnesium, long-chain dibasic acid calcium, long-chain dibasic acid sodium, etc.
[0044] A mixed solution of a long carbon chain dibasic acid and an organic solvent, wherein the organic solvent is toluene, xylene, chlorobenzene, dichlorobenzene, nitrobenzene, ethyl acetate, isopropyl acetate, methyl acetate, butyl acetate, octyl acetate, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, ethylene glycol dipentyl ether, ethylene glycol dihexyl ether, ethylene glycol diheptyl ether, ethylene glycol dioctyl ether, ethylene glycol dinonyl ether, ethylene glycol didecyl ether, ethylene glycol dilauryl ether, methyl chloride, acetic acid, propionic acid, butyric acid, malonic acid, butyric acid One, two or more of the following: diacid, adipic acid, terephthalic acid, ethyl ether, propyl ether, amyl ether, hexyl ether, heptyl ether, octyl ether, nonyl ether, decyl ether, lauryl ether, methyl tert-butyl ether, acetone, butanone, methanol, ethanol, butanol, propanol, ethylene glycol, propylene glycol, 1,4-butanediol, tetrahydrofuran, 1,4-dioxane, DMSO, methyl ethyl ether, methyl butyl ether, methyl octyl ether, ethyl ethyl ether, ethyl butyl ether, ethyl octyl ether, anisole, phenethyl ether, phenbutyl ether, phenoctyl ether, and chloroform.
[0045] Specifically, the present invention adopts acid precipitation crystallization to precipitate long-chain dibasic acid. By regulating the production conditions of the concentration crystallization process, through aging crystallization, turbine centrifuge separation, and boiling drying, large-particle long-chain dibasic acid crystals with a size of 10 to 200 mesh are obtained, which are the desired product of the present invention.
[0046] The following experimental methods and detection methods, unless otherwise specified, are conventional methods; the following reagents and raw materials, unless otherwise specified, are commercially available reagents and raw materials, and are not particularly limited in this invention. The collected material of the present invention was detected by dry weight method, and the nitrogen content was determined by Kjeldahl method. The purity of the long-chain dicarboxylic acid was determined by liquid chromatography tandem mass spectrometry (LCMS) combined with standard samples.
[0047] It should be noted that the long-chain dibasic acid fermentation broth provided by the present invention is prepared according to the following steps:
[0048] Two-stage seed tanks were used to culture the organisms, and the bacterial growth density (OD620) after culture in the first-stage seed tank was ≥0.5;
[0049] The specific steps are as follows:
[0050] (1) First-level seed tank culture: alkaline water boiling tank: pH ≈ 12, 120℃, 4h; air disinfection: 130℃, 1h; actual disinfection: before disinfection, adjust the pH appropriately to make the pH before seeding within the range of 6.7-7.0. Temperature 121-123℃, keep warm for 30 minutes, the volume after actual disinfection is 1.4-1.6m 3 After the disinfection is completed, the temperature is quickly lowered. When the temperature drops to 30℃±0.5℃, tropical Candida is inoculated and cultured.
[0051] In the first-level culture process, the initial culture is normal. When the dissolved oxygen is close to 40%, the air volume is increased to ensure that the dissolved oxygen is maintained at 40% to 50%. The air volume is gradually increased. When the bacterial growth density (OD 620 ) was 0.540, the dissolved oxygen and pH of the bacterial solution rebounded, and the first-level culture was completed.
[0052] (2) Secondary seed tank culture: Alkaline water boiling tank: pH ≈ 12, 120℃, 4h; air disinfection: 130℃, 1h; before disinfection, the volume is 17.5t. Before disinfection, the pH is appropriately adjusted to keep the pH before seeding within the range of 6.7-7.0. The temperature is 121-123℃, and the temperature is kept warm for 30 minutes. After disinfection, the temperature is quickly lowered. When the carbon source is glucose, the volume of the single disinfection tank is 1.5t, and the volume of the secondary seed tank is 16t. The temperature is 113-115℃, and the temperature is kept warm for 30 minutes. Before inoculation, the seed is pressed into the secondary seed tank.
[0053] The secondary culture process is controlled as follows: in the early stage of normal culture, when the dissolved oxygen is close to 40%, the air volume is increased to ensure that the dissolved oxygen is maintained at 40% to 50%, and the air volume is gradually increased; when the dissolved oxygen and pH of the bacterial liquid rebound, the secondary culture is completed.
[0054] After the secondary seed tank culture is completed, the bacterial liquid is transferred to a fermentation tank for fermentation. (The fermentation tank contains a culture medium consisting of 2% sucrose, 0.3% corn steep liquor, 0.5% yeast extract, 0.8% potassium dihydrogen phosphate, and 0.3% urea.) During fermentation, the ventilation ratio is maintained at 1:0.7, and the dissolved oxygen level is controlled at approximately 30%. The pH is continuously adjusted over time, gradually increasing from 6.0 to a final pH of 8.0. To control the pH, an alkane is added continuously: 10% at 24 hours, 5% at 48 hours, 10% at 72 hours, and 5% at 96 hours. The percentage of alkane added refers to the mass percentage of the fermentation liquid. The alkane added is determined by the type of dibasic acid being produced. For example, in Example 1, for the production of DC13 dibasic acid, n-tridecane is added; in Example 3, for the production of DC12 dibasic acid, n-dodecane is added. After 158 hours of fermentation, a dibasic acid fermentation liquid is obtained.
[0055] Example 1
[0056] The long carbon chain sodium dibasic acid aqueous solution used in this embodiment was prepared according to the following steps:
[0057] 1000 L of tridecanedioic acid fermentation broth, containing 145 g / L of tridecanedioic acid, was filtered through a 0.02 μm pore size stainless steel membrane at a membrane inlet pressure of 0.6 MPa to obtain a fermentation broth supernatant (a). 1500 L of fermentation broth supernatant (a) was collected and decolorized with 6% activated carbon. The supernatant was filtered to obtain a decolorized supernatant (b), which is an aqueous solution of sodium long-chain dicarboxylic acid.
[0058] For the preparation of large-particle long-chain dicarboxylic acid crystals, the following steps are specifically followed:
[0059] Step (1) transferring the long-chain dicarboxylic acid sodium aqueous solution into an acid precipitation crystallization tank, adding 93% concentrated sulfuric acid by mass to adjust the pH to 4.5, raising the temperature to 95° C. and maintaining for 45 minutes until the tridecanedioic acid in the acidified crystallization solution is completely precipitated to obtain a long-chain dicarboxylic acid suspension.
[0060] Step (2): The long-chain dicarboxylic acid suspension in step (1) is transferred to a concentration crystallization tank, and a dry powdered tridecyl long-chain dicarboxylic acid product is added to the concentration crystallization tank at a ratio of 10%. The cooling rate is controlled at 2°C / min until the cooling temperature drops to 35°C, the stirring rate is controlled to 125 rpm, the pH value is controlled to 4.0, and the time is controlled to 3 hours. The bulk density of the long-chain dicarboxylic acid crystals is increased by more than 2 times, and large particles of the long-chain dicarboxylic acid are formed.
[0061] Step (3), transferring the large particles of long carbon chain dicarboxylic acid containing water obtained in step (2) into a turbine centrifuge, and separating the water by utilizing the particle size and gravity principle to obtain large particles of long carbon chain dicarboxylic acid crystals with a water content of 5%;
[0062] Step (4): The large-particle long carbon chain dicarboxylic acid crystals with a water content of 5% obtained in step (3) are transferred to a boiling dryer for drying to obtain 131.0 kg of finished large-particle long carbon chain dicarboxylic acid crystals.
[0063] After testing, the monoacid purity of the large-particle long-carbon-chain dibasic acid crystals is 97.88%, the total acid purity is 99.1%, the water content is 0.9%, and the crystal size is 10 mesh to 200 mesh.
[0064] Example 2
[0065] The method for preparing large-particle long-carbon-chain dibasic acid crystals comprises the following steps:
[0066] Step (1), the sodium tridecane long-chain dicarboxylic acid aqueous solution in Example 1 is transferred to an acid precipitation crystallization tank, 93% by mass concentrated sulfuric acid is added to adjust the pH to 4.5, and the temperature is raised to 95° C. and maintained for 1 hour until the tridecane dicarboxylic acid in the acidified crystallization solution is completely precipitated to obtain a long-chain dicarboxylic acid suspension.
[0067] Step (2): The long-chain dicarboxylic acid suspension in step (1) is transferred to a concentration crystallization tank, and a dry powdered tridecyl long-chain dicarboxylic acid product is added to the concentration crystallization tank at a ratio of 30%. The cooling rate is controlled at 2.5°C / min until the cooling temperature drops to 30°C, the stirring rate is controlled to 150 rpm, the pH value is controlled to 4.5, and the time is controlled to 3 hours. The bulk density of the long-chain dicarboxylic acid crystals is increased by more than 2 times, and large particles of the long-chain dicarboxylic acid are formed.
[0068] Step (3), transferring the large particles of long carbon chain dicarboxylic acid containing water obtained in step (2) into a horizontal spiral centrifuge, and separating the water by utilizing the particle size and gravity principle to obtain large particles of long carbon chain dicarboxylic acid crystals with a water content of 6%;
[0069] Step (4), transferring the large-particle long carbon chain dicarboxylic acid crystals with a water content of 6% obtained in step (3) into a fluidized bed dryer for drying to obtain a finished large-particle long carbon chain dicarboxylic acid crystal.
[0070] After testing, the single acid purity of the large-particle long-carbon-chain dibasic acid crystals is 97.7%, the total acid purity is 99.0%, the water content is 1.0%, and the crystal size is 10 mesh to 200 mesh.
[0071] Example 3
[0072] The long carbon chain sodium dibasic acid aqueous solution used in this embodiment was prepared according to the following steps:
[0073] 500 L of DC12 dibasic acid fermentation broth (with a DC12 dibasic acid concentration of 130 g / L) was filtered through a 0.5 μm pore size stainless steel or ceramic membrane at a membrane inlet pressure of 0.4 MPa to obtain fermentation broth supernatant a. A total of 650 L of fermentation broth supernatant a was collected and decolorized with 1% activated carbon. The supernatant b was filtered to obtain the decolorized supernatant b, which is the aqueous solution of long-chain sodium dibasic acid.
[0074] For the preparation of large-particle crystals of dodecanedioic acid, the following steps are specifically followed:
[0075] Step (1) transferring the long-chain dicarboxylic acid sodium aqueous solution into an acid precipitation crystallization tank, adding 93% concentrated sulfuric acid by mass to adjust the pH to 4.6, raising the temperature to 95° C. and maintaining for 45 minutes until the dodecane dicarboxylic acid in the acidified crystallization solution is completely precipitated to obtain a long-chain dicarboxylic acid suspension.
[0076] Step (2): The long-chain dicarboxylic acid suspension prepared in step (1) is transferred to a concentration crystallization tank, and a dry powdered finished product of a 12-carbon long-chain dicarboxylic acid is added to the concentration crystallization tank at a ratio of 20%. The cooling rate is controlled at 2° C. / min until the cooling temperature drops to 25° C., the stirring rate is controlled at 125 rpm, the pH value is controlled at 4.0, and the stirring time is controlled at 3 hours. The bulk density of the long-chain dicarboxylic acid crystals is increased by more than 2 times, and large particles of the long-chain dicarboxylic acid are formed.
[0077] Step (3), transferring the large particles of long carbon chain dicarboxylic acid containing water obtained in step (2) into a turbine centrifuge, and separating the water by utilizing the particle size and gravity principle to obtain large particles of long carbon chain dicarboxylic acid crystals with a water content of 5%;
[0078] Step (4): The large-particle long carbon chain dicarboxylic acid crystals with a water content of 5% obtained in step (3) are transferred to a boiling dryer for drying to obtain 48.91 kg of finished large-particle long carbon chain dicarboxylic acid crystals.
[0079] After testing, the single acid purity of the large-particle long-carbon chain dibasic acid crystals is 98.38%, the total acid purity is 99.2%, the water content is 0.8%, and the crystal size is 10 mesh to 200 mesh.
[0080] Example 4
[0081] 500 L of DC16 dicarboxylic acid fermentation broth, wherein the concentration of DC16 dicarboxylic acid is 9%, is filtered through a 0.5 μm pore size stainless steel membrane or a ceramic membrane at an inlet pressure of 0.4 MPa to obtain fermentation broth supernatant a. A total of 695 L of fermentation broth supernatant a is collected, 0.15% activated carbon is added for decolorization, and the supernatant b is filtered to obtain a sodium hexadecanedioate aqueous solution.
[0082] The preparation and processing of large particle crystals of hexadecane long carbon chain dibasic acid is specifically carried out in the following steps:
[0083] Step (1) transferring the sodium long-chain dicarboxylic acid aqueous solution into an acid precipitation crystallization tank, adding 95% concentrated sulfuric acid to adjust the pH to 3.8, heating to 95° C. and maintaining for 1 hour and 15 minutes until the hexadecane dicarboxylic acid in the acidified crystallization solution is completely precipitated to obtain a long-chain dicarboxylic acid suspension.
[0084] Step (2): The long-chain dicarboxylic acid suspension prepared in step (1) is transferred to a concentration crystallization tank, and a dry powdered hexadecane long-chain dicarboxylic acid product is added to the concentration crystallization tank at a ratio of 10%. The cooling rate is controlled at 1.5° C. / min until the cooling temperature drops to 35° C., the stirring rate is controlled at 180 rpm, the pH value is controlled at 4.0, and the stirring time is controlled at 3 hours. The bulk density of the long-chain dicarboxylic acid crystals is increased by more than 2 times, and large particles of the long-chain dicarboxylic acid are formed.
[0085] Step (3), transferring the large-particle long carbon chain dicarboxylic acid containing water obtained in step (2) into a turbine centrifuge, and separating the water by utilizing the particle size and gravity principle to obtain large-particle long carbon chain dicarboxylic acid crystals with a water content of 8%;
[0086] Step (4): The large-particle long carbon chain dicarboxylic acid crystals with a water content of 8% obtained in step (3) are transferred to a boiling dryer for drying to obtain 30.93 kg of finished large-particle long carbon chain dicarboxylic acid crystals.
[0087] After testing, the monoacid purity of the large-particle long-carbon-chain dibasic acid crystals was 97.38%, the total acid purity was 98.2%, the water content was 1.0%, and the crystal size was 10 mesh to 200 mesh.
[0088] Example 5
[0089] 500 L of DC18 dicarboxylic acid fermentation broth, containing 5% DC18 dicarboxylic acid, was filtered through a 0.5 μm pore size stainless steel or ceramic membrane at an inlet pressure of 0.4 MPa to obtain fermentation broth supernatant a. 695 L of fermentation broth supernatant a was collected, decolorized with 0.15% activated carbon, and filtered to obtain decolorized supernatant b. Sulfuric acid was added to adjust the pH to 4.5. The mixture was heated to 95°C and held for 45 minutes, then cooled to 20°C and allowed to stand until the DC18 dicarboxylic acid in the acidified crystals was completely precipitated. The mixture was then filtered through a plate and frame filter press at a pressure of 0.4 MPa to obtain a filter cake, which was then dried in an oven at 100°C to obtain crude DC18 dicarboxylic acid with a water content of approximately 2%. Testing revealed a monoacid purity of 97.35% for the crude dicarboxylic acid.
[0090] The crude octadecane long-chain dicarboxylic acid is purified and refined according to the following steps:
[0091] (1) 5 kg of crude DC18 dibasic acid was stirred and mixed with a mixed solvent of 50 L of dibutyl ether and 10 L of isooctyl acetate in a decolorization tank, heated to 95°C to completely dissolve the crude dibasic acid, and allowed to stand at a constant temperature for 25 minutes. After draining the lower layer of water while maintaining the temperature, activated carbon was added to the oil phase in an amount of 0.15% of the mass of the oil phase. After sufficient stirring and mixing for 30 minutes, the mixture was filtered to obtain a solvent clear liquid A. The solvent clear liquid A was cooled to 15°C with the aid of jacket water, and the long-chain dibasic acid crystals were precipitated. The mixture was filtered through a plate and frame filter press to obtain a refined crystallization filter cake of DC18 dibasic acid and a crystallization mother liquor.
[0092] (2) The crystallization mother liquor of step (1) is transported to a mother liquor recovery tank and activated carbon is added. The amount of activated carbon added is 0.15% of the mass of the crystallization mother liquor. The mixture is fully stirred and mixed for about 30 minutes. The mixture is filtered through a plate and frame filter at a filtration pressure of 0.4 MPa. The filtered supernatant B is collected and transferred to a decolorization tank as the organic solvent for the next batch of refining.
[0093] The filtered supernatant B was used as the organic solvent for the next batch of step (1). No new organic solvent was added during the treatment process. A total of 5 batches were cycled according to the same process and conditions as steps (1) to (2). A total of 25 kg of crude DC18 dibasic acid was processed. The refined dibasic acid filter cake obtained in each batch of step (2) was collected and dried at 100° C. to obtain 23.51 kg of refined dibasic acid product with a monoacid purity of 99.12%.
[0094] The preparation and processing of large particle crystals of 18-carbon long-chain dibasic acid is specifically carried out in the following steps:
[0095] Step (1): 5 kg of refined DC18 dicarboxylic acid was stirred and mixed with a mixed solvent of 50 L of dibutyl ether and 10 L of isooctyl acetate in a concentration crystallization tank, and heated to 95° C. to completely dissolve the refined DC18 dicarboxylic acid.
[0096] Step (2), adding the dried powdered 18-carbon long-chain dicarboxylic acid product to the concentration crystallization tank at a ratio of 10%, controlling the cooling rate to 1°C / min until the cooling temperature drops to 36°C, controlling the stirring rate to 200 rpm, controlling the pH value to 4.6, and controlling the time to 5 hours, large particles of 18-carbon long-chain dicarboxylic acid are formed.
[0097] Step (3), transferring the large particles of long carbon chain dicarboxylic acid containing water obtained in step (2) into a disc centrifuge, and separating the water by particle size and gravity to obtain large particles of long carbon chain dicarboxylic acid crystals with a water content of 9%;
[0098] Step (4): The large-particle long carbon chain dicarboxylic acid crystals with a water content of 9% obtained in step (3) are transferred to a fluidized bed dryer for drying to obtain 4.90 kg of finished large-particle long carbon chain dicarboxylic acid crystals.
[0099] After testing, the large-particle long-carbon-chain dibasic acid crystals have a single acid purity of 99.85%, a total acid purity of 99.92%, a water content of 0.8%, and a crystal size of 10 mesh to 200 mesh.
[0100] Example 6
[0101] 500 L of DC11 dibasic acid fermentation broth, containing a 12% concentration of DC11 dibasic acid, was filtered through a 0.5 μm pore size stainless steel or ceramic membrane at an inlet pressure of 0.4 MPa to obtain a fermentation broth supernatant (a). 695 L of fermentation broth supernatant (a) was collected and decolorized with 0.15% activated carbon. The decolorized supernatant was filtered to obtain a decolorized supernatant. Sulfuric acid was added to adjust the pH to 4.5. The solution was heated to 95°C and held for 45 minutes, then cooled to 20°C and allowed to stand until the DC11 dibasic acid in the acidified crystals was completely precipitated. The filter cake was then filtered through a plate and frame filter press at a pressure of 0.4 MPa. The filter cake was dried in an oven at 100°C to obtain a crude DC11 dibasic acid product with a water content of approximately 2%. Testing revealed a monoacid purity of 97.25% for the crude product.
[0102] The crude product of 11-carbon long-chain dicarboxylic acid is purified and refined according to the following steps:
[0103] (1) 5.816 kg of crude DC11 dicarboxylic acid was stirred and mixed with 50 L of a mixed solvent of diisopropyl ether and n-octyl ether in a decolorizing tank, heated to 95°C to completely dissolve the crude dicarboxylic acid, and allowed to stand at a constant temperature for 25 minutes. After draining the water in the lower layer while maintaining the temperature, activated carbon was added to the oil phase in an amount of 0.15% of the mass of the oil phase. After sufficient stirring and mixing for 30 minutes, the mixture was filtered to obtain a solvent clear liquid A. The solvent clear liquid A was cooled to 15°C with the aid of jacket water, and the long-chain dicarboxylic acid crystals were precipitated. The mixture was filtered through a plate and frame filter press to obtain a refined crystallization filter cake of DC11 dicarboxylic acid and a crystallization mother liquor.
[0104] (2) The crystallization mother liquor of step (1) is transported to a mother liquor recovery tank and activated carbon is added. The amount of activated carbon added is 0.15% of the mass of the crystallization mother liquor. The mixture is fully stirred and mixed for about 30 minutes. The mixture is filtered through a plate and frame filter at a filtration pressure of 0.4 MPa. The filtered supernatant B is collected and transferred to a decolorization tank as the organic solvent for the next batch of refining.
[0105] The filtered supernatant B was used as the organic solvent for the next batch of step (1). No new organic solvent was added during the treatment process. A total of 5 batches were cycled according to the same process and conditions as steps (1) to (2). A total of 29.073 kg of crude DC11 dibasic acid was processed. The refined dibasic acid filter cake obtained in each batch of step (2) was collected and dried at 100° C. to obtain 28.49 kg of refined dibasic acid product with a monoacid purity of 99.03%.
[0106] The preparation and processing of large-particle crystals of 11-carbon long-chain dibasic acid is specifically carried out in the following steps:
[0107] Step (1): 5 kg of refined DC11 dicarboxylic acid was stirred and mixed with a mixed solvent of 50 L of diisopropyl ether and 10 L of n-octyl ether in a concentration crystallization tank, and heated to 95° C. to completely dissolve the refined DC11 dicarboxylic acid.
[0108] In step (2), the dried powdered 11-carbon long-chain dicarboxylic acid product is added to the concentration crystallization tank at a ratio of 15%, the cooling rate is controlled at 2.5°C / min until the cooling temperature drops to 30°C, the stirring rate is controlled at 150 rpm, the pH value is controlled at 4.0, and the time is controlled at 3 hours, until large particles of 11-carbon long-chain dicarboxylic acid are formed.
[0109] Step (3), transferring the large particles of long carbon chain dicarboxylic acid containing water obtained in step (2) into a turbine centrifuge, and separating the water by utilizing the particle size and gravity principle to obtain large particles of long carbon chain dicarboxylic acid crystals with a water content of 8%;
[0110] Step (4): The large-particle long carbon chain dicarboxylic acid crystals with a water content of 8% obtained in step (3) are transferred to a fluidized bed dryer for drying to obtain 4.93 kg of finished large-particle long carbon chain dicarboxylic acid crystals.
[0111] After testing, the single acid purity of the large-particle long-carbon chain dibasic acid crystals is 99.64%, the total acid purity is 99.93%, the water content is 0.6%, and the crystal size is 10 mesh to 200 mesh.
[0112] Example 7
[0113] 500 L of DC12 dibasic acid fermentation broth, containing a 16% concentration of DC12 dibasic acid, was filtered through a 0.5 μm pore size stainless steel or ceramic membrane at an inlet pressure of 0.4 MPa to obtain fermentation broth supernatant a. 695 L of fermentation broth supernatant a was collected and decolorized with 0.15% activated carbon. The supernatant b was filtered and adjusted to pH 4.5 by adding sulfuric acid. The solution was heated to 95°C and held for 45 minutes, then cooled to 20°C and allowed to stand until the DC12 dibasic acid in the acidified crystals was completely precipitated. The filter cake was then filtered through a plate and frame filter press at a pressure of 0.4 MPa. The filter cake was dried in an oven at 100°C to obtain crude DC12 dibasic acid with a water content of approximately 2%. Testing revealed a monoacid purity of 97.25% for the crude dibasic acid.
[0114] The crude long-chain dibasic acid is purified and refined according to the following steps:
[0115] (1) 5.816 kg of crude DC12 dibasic acid was mixed with 50 L of butanone and 10 L of ether in a decolorization tank, heated to 95°C to completely dissolve the crude dibasic acid, and allowed to stand at a constant temperature for 25 minutes. After draining the lower layer of water while maintaining the temperature, activated carbon was added to the oil phase in an amount of 0.15% of the mass of the oil phase. After sufficient stirring and mixing for 30 minutes, the mixture was filtered to obtain a solvent clear liquid A. The solvent clear liquid A was cooled to 15°C with the aid of jacket water, and the long-chain dibasic acid crystals were precipitated. The solution was filtered through a plate and frame filter press to obtain a refined crystal cake of DC12 dibasic acid and a crystallization mother liquor.
[0116] (2) The crystallization mother liquor of step (1) is transported to a mother liquor recovery tank and activated carbon is added. The amount of activated carbon added is 0.15% of the mass of the crystallization mother liquor. The mixture is fully stirred and mixed for about 30 minutes. The mixture is filtered through a plate and frame filter at a filtration pressure of 0.4 MPa. The filtered supernatant B is collected and transferred to a decolorization tank as the organic solvent for the next batch of refining.
[0117] The filtered supernatant B was used as the organic solvent for the next batch of step (1) without adding new organic solvent. A total of 5 batches were cycled according to the same process and conditions as steps (1) to (2), and a total of 29.038 kg of crude DC12 dibasic acid was processed. The refined dibasic acid filter cake obtained in each batch of step (2) was collected and dried at 100° C. to obtain 28.47 kg of refined dibasic acid product with a monoacid purity of 99.25%.
[0118] The preparation and processing of large particle crystals of twelve carbon long chain dibasic acid is specifically carried out in the following steps:
[0119] Step (1): 5 kg of refined DC12 dicarboxylic acid was stirred and mixed with a mixed solvent of 50 L of butanone and 10 L of ether in a concentration crystallization tank, and heated to 92° C. to completely dissolve the refined DC12 dicarboxylic acid.
[0120] In step (2), a dry powdered product of a 12-carbon long-chain dicarboxylic acid is added to a concentration crystallization tank at a ratio of 25%, and the cooling rate is controlled at 2.8°C / min until the cooling temperature drops to 35°C. The stirring rate is controlled at 160 rpm, the pH value is controlled at 4.5, and the crystallization time is controlled at 3 hours, until large particles of the 12-carbon long-chain dicarboxylic acid are formed.
[0121] Step (3), transferring the large particles of long carbon chain dicarboxylic acid containing water obtained in step (2) into a disc centrifuge, and separating the water by utilizing the particle size and gravity principle to obtain large particles of long carbon chain dicarboxylic acid crystals with a water content of 6%;
[0122] Step (4): The large-particle long carbon chain dicarboxylic acid crystals with a water content of 6% obtained in step (3) are transferred to a fluidized bed dryer for drying to obtain 4.89 kg of finished large-particle long carbon chain dicarboxylic acid crystals.
[0123] After testing, the single acid purity of the large-particle long-carbon chain dibasic acid crystals is 99.75%, the total acid purity is 99.92%, the water content is 1.5%, and the crystal size is 10 mesh to 200 mesh.
[0124] Example 8
[0125] 500 L of DC13 dibasic acid fermentation broth, containing a 15% DC13 dibasic acid concentration, was filtered through a 0.5 μm pore size stainless steel or ceramic membrane at a membrane inlet pressure of 0.4 MPa to obtain supernatant a. 695 L of supernatant a was collected and decolorized with 0.15% activated carbon. The decolorized supernatant b was filtered and adjusted to pH 4.5 by adding sulfuric acid. The solution was heated to 95°C and held for 45 minutes, then cooled to 20°C and allowed to stand until the DC13 dibasic acid in the acidified crystals was completely precipitated. The filter cake was then filtered through a plate and frame filter press at a pressure of 0.4 MPa. The filter cake was dried in an oven at 100°C to obtain crude DC13 dibasic acid with a water content of approximately 2%. Testing revealed a monoacid purity of 97.25% for the crude dibasic acid.
[0126] The crude long-chain dibasic acid is purified and refined according to the following steps:
[0127] (1) 5.816 kg of crude DC13 dibasic acid was mixed with 50 L of a mixed solvent of methyl tert-butyl ether and 10 L of butanone in a decolorization tank, heated to 95°C to completely dissolve the crude dibasic acid, and allowed to stand at a constant temperature for 25 minutes. After draining the lower layer of water while maintaining the temperature, activated carbon was added to the oil phase in an amount of 0.15% of the mass of the oil phase. After sufficient stirring and mixing for 30 minutes, the solvent was filtered to obtain a solvent clear liquid A. The solvent clear liquid A was cooled to 15°C with the aid of jacket water, and the long-chain dibasic acid crystals were precipitated. The solution was filtered through a plate and frame filter press to obtain a refined crystal cake of DC13 dibasic acid and a crystallization mother liquor.
[0128] (2) The crystallization mother liquor of step (1) is transported to a mother liquor recovery tank and activated carbon is added. The amount of activated carbon added is 0.15% of the mass of the crystallization mother liquor. The mixture is fully stirred and mixed for about 30 minutes. The mixture is filtered through a plate and frame filter at a filtration pressure of 0.4 MPa. The filtered supernatant B is collected and transferred to a decolorization tank as the organic solvent for the next batch of refining.
[0129] The filtered supernatant B was used as the organic solvent for the next batch of step (1) without adding new organic solvent. A total of 5 batches were cycled according to the same process and conditions as steps (1) to (2), and a total of 29.03 kg of crude DC13 dibasic acid was processed. The refined dibasic acid filter cake obtained in each batch of step (2) was collected and dried at 100° C. to obtain 28.47 kg of refined dibasic acid product with a monoacid purity of 99.13%.
[0130] The preparation and processing of large-particle crystals of tridecanol long-chain dicarboxylic acid is specifically carried out in the following steps:
[0131] Step (1): 5 kg of refined DC13 dibasic acid was stirred and mixed with a mixed solvent of 50 L of methyl tert-butyl ether and 10 L of butanone in a concentration crystallization tank, and heated to 95° C. to completely dissolve the refined DC13 dibasic acid.
[0132] In step (2), a dry powdered tridecanol long-chain dicarboxylic acid product is added to a concentration crystallization tank at a ratio of 25%, and the cooling rate is controlled at 2.5°C / min until the cooling temperature drops to 35°C. The stirring rate is controlled at 160 rpm, the pH value is controlled at 4.0, and the crystallization time is controlled at 3 hours, until large particles of tridecanol long-chain dicarboxylic acid are formed.
[0133] Step (3), transferring the large-particle long carbon chain dicarboxylic acid containing water obtained in step (2) into a horizontal spiral centrifuge, and separating the water by utilizing the particle size and gravity principle to obtain large-particle long carbon chain dicarboxylic acid crystals with a water content of 8%;
[0134] Step (4): The large-particle long carbon chain dicarboxylic acid crystals with a water content of 8% obtained in step (3) are transferred to a spray dryer for drying to obtain 4.83 kg of finished large-particle long carbon chain dicarboxylic acid crystals.
[0135] After testing, the large-particle long-carbon-chain dibasic acid crystals have a single acid purity of 99.55%, a total acid purity of 99.82%, a water content of 0.8%, and a crystal size of 10 mesh to 200 mesh.
[0136] Example 9
[0137] 500 L of DC15 dibasic acid fermentation broth, containing a 16% concentration of DC15 dibasic acid, was filtered through a 0.5 μm pore size stainless steel or ceramic membrane at an inlet pressure of 0.4 MPa to obtain fermentation broth supernatant a. 695 L of fermentation broth supernatant a was collected, decolorized with 0.15% activated carbon, and filtered to obtain decolorized supernatant b. Sulfuric acid was added to adjust the pH to 4.5. The solution was heated to 95°C and held for 45 minutes, then cooled to 20°C and allowed to stand until the DC15 dibasic acid in the acidified crystals was completely precipitated. The filter cake was then filtered through a plate and frame filter press at a pressure of 0.4 MPa. The filter cake was dried in an oven at 100°C to obtain crude DC15 dibasic acid with a water content of approximately 2%. Testing revealed a monoacid purity of 97.25% for the crude dibasic acid.
[0138] The crude long-chain dibasic acid is purified and refined according to the following steps:
[0139] (1) 5.816 kg of crude DC15 dicarboxylic acid was stirred and mixed with a mixed solvent of 50 L of isooctyl ether and 10 L of acetic acid in a decolorization tank, and heated to 95°C to completely dissolve the crude dicarboxylic acid. After standing at a constant temperature for 25 minutes, the lower layer of water was drained while the temperature was kept high, and activated carbon was added to the oil phase in an amount of 0.15% of the mass of the oil phase. After sufficient stirring and mixing for 30 minutes, the mixture was filtered to obtain a solvent clear solution A.
[0140] The solvent clear liquid A was cooled to 15° C. with the aid of jacket water, and the long-chain dibasic acid crystals were precipitated. The long-chain dibasic acid was filtered through a plate and frame filter press to obtain a refined crystal cake of DC15 dibasic acid and a crystallization mother liquor.
[0141] (2) The crystallization mother liquor of step (1) is transported to a mother liquor recovery tank and activated carbon is added. The amount of activated carbon added is 0.15% of the mass of the crystallization mother liquor. The mixture is fully stirred and mixed for about 30 minutes. The mixture is filtered through a plate and frame filter at a filtration pressure of 0.4 MPa. The filtered supernatant B is collected and transferred to a decolorization tank as the organic solvent for the next batch of refining.
[0142] The filtered supernatant B was used as the organic solvent for the next batch of step (1). No new organic solvent was added during the treatment process. A total of 5 batches were cycled according to the same process and conditions as steps (1) to (2). A total of 29.04 kg of crude DC15 dibasic acid was processed. The refined dibasic acid filter cake obtained in each batch of step (2) was collected and dried at 100° C. to obtain 28.47 kg of refined dibasic acid product with a monoacid purity of 99.18%.
[0143] The preparation and processing of large particle crystals of 15-carbon long-chain dibasic acid is specifically carried out in the following steps:
[0144] Step (1): 5 kg of refined DC15 dicarboxylic acid was stirred and mixed with a mixed solvent of 50 L of isooctyl ether and 10 L of acetic acid in a concentration crystallization tank, and heated to 95° C. to completely dissolve the refined DC15 dicarboxylic acid.
[0145] In step (2), a dry powdered 15-carbon long-chain dicarboxylic acid product is added to a concentration crystallization tank at a ratio of 15%, and the cooling rate is controlled at 1.8°C / min until the cooling temperature drops to 35°C. The stirring rate is controlled at 180 rpm, the pH value is controlled at 4.6, and the time is controlled at 3.5 hours. Large particles of 10-carbon-free long-chain dicarboxylic acid are formed.
[0146] Step (3), transferring the large particles of long carbon chain dicarboxylic acid containing water obtained in step (2) into a turbine centrifuge, and separating the water by utilizing the particle size and gravity principle to obtain large particles of long carbon chain dicarboxylic acid crystals with a water content of 6%;
[0147] Step (4): The large-particle long carbon chain dicarboxylic acid crystals with a water content of 6% obtained in step (3) are transferred to a fluidized bed dryer for drying to obtain 4.89 kg of finished large-particle long carbon chain dicarboxylic acid crystals.
[0148] After testing, the large-particle long-carbon-chain dibasic acid crystals have a single acid purity of 99.55%, a total acid purity of 99.82%, a water content of 0.8%, and a crystal size of 10 mesh to 200 mesh.
[0149] Example 10
[0150] 500 L of DC16 dibasic acid fermentation broth, containing a 16% concentration of DC16 dibasic acid, was filtered through a 0.5 μm pore size stainless steel or ceramic membrane at an inlet pressure of 0.4 MPa to obtain fermentation broth supernatant a. 695 L of fermentation broth supernatant a was collected and decolorized with 0.15% activated carbon. The supernatant b was filtered and adjusted to pH 4.5 by adding sulfuric acid. The solution was heated to 95°C and held for 45 minutes, then cooled to 20°C and allowed to stand until the DC16 dibasic acid in the acidified crystals was completely precipitated. The filter cake was then filtered through a plate and frame filter press at a pressure of 0.4 MPa. The filter cake was dried in an oven at 100°C to obtain crude DC16 dibasic acid with a water content of approximately 2%. Testing revealed a monoacid purity of 97.25% for the crude dibasic acid.
[0151] The crude long-chain dibasic acid is purified and refined according to the following steps:
[0152] (1) 5.816 kg of crude DC16 dicarboxylic acid was stirred and mixed with a mixed solvent of 50 L of dibutyl ether and 10 L of acetic acid in a decolorizing tank, heated to 95°C to completely dissolve the crude dicarboxylic acid, and allowed to stand at a constant temperature for 25 minutes. After draining the water in the lower layer while maintaining the temperature, activated carbon was added to the oil phase in an amount of 0.15% of the mass of the oil phase. After sufficient stirring and mixing for 30 minutes, the mixture was filtered to obtain a solvent clear liquid A. The solvent clear liquid A was cooled to 15°C with the aid of jacket water, and the long-chain dicarboxylic acid crystals were precipitated. The mixture was filtered through a plate and frame filter press to obtain a refined crystal cake of DC16 dicarboxylic acid and a crystallization mother liquor.
[0153] (2) The crystallization mother liquor of step (1) is transported to a mother liquor recovery tank and activated carbon is added. The amount of activated carbon added is 0.15% of the mass of the crystallization mother liquor. The mixture is fully stirred and mixed for about 30 minutes. The mixture is filtered through a plate and frame filter at a filtration pressure of 0.4 MPa. The filtered supernatant B is collected and transferred to a decolorization tank as the organic solvent for the next batch of refining.
[0154] The filtered supernatant B was used as the organic solvent for the next batch of step (1). No new organic solvent was added during the treatment process. A total of 5 batches were cycled according to the same process and conditions as steps (1) to (2). A total of 29.01 kg of crude DC16 dibasic acid was processed. The refined dibasic acid filter cake obtained in each batch of step (2) was collected and dried at 100° C. to obtain 28.47 kg of refined dibasic acid product with a monoacid purity of 99.07%.
[0155] The preparation and processing of large particle crystals of hexadecane long carbon chain dibasic acid is specifically carried out in the following steps:
[0156] Step (1): 5 kg of refined DC16 dibasic acid was stirred and mixed with a mixed solvent of 50 L of dibutyl ether and 10 L of acetic acid in a concentration crystallization tank, and heated to 95° C. to completely dissolve the refined DC16 dibasic acid.
[0157] In step (2), the dried powdered hexadecane long-chain dicarboxylic acid product is added to the concentration crystallization tank at a ratio of 20%, the cooling rate is controlled at 1.5°C / min until the cooling temperature drops to 35°C, the stirring rate is controlled at 200 rpm, the pH value is controlled at 4.6, and the time is controlled at 4.5 hours, until large particles of hexadecane long-chain dicarboxylic acid are formed.
[0158] Step (3), transferring the large particles of long carbon chain dicarboxylic acid containing water obtained in step (2) into a disc centrifuge, and separating the water by utilizing the particle size and gravity principle to obtain large particles of long carbon chain dicarboxylic acid crystals with a water content of 5%;
[0159] Step (4): The large-particle long carbon chain dicarboxylic acid crystals with a water content of 5% obtained in step (3) are transferred to a fluidized bed dryer for drying to obtain 4.73 kg of finished large-particle long carbon chain dicarboxylic acid crystals.
[0160] After testing, the single acid purity of the large-particle long-carbon chain dibasic acid crystals is 99.45%, the total acid purity is 99.82%, the water content is 1.0%, and the crystal size is 10 mesh to 200 mesh.
[0161] Example 11
[0162] The preparation of DC16 dibasic acid crystals differs from that of Example 10 in that the preparation process of large-particle crystals of the hexadecane long carbon chain dibasic acid is different, specifically:
[0163] Step (1): 5 kg of refined DC16 dicarboxylic acid was stirred and mixed with a mixed solvent of 50 L of ethylene glycol dioctyl ether and 10 L of acetic acid in a concentration crystallization tank, and heated to 95° C. to completely dissolve the refined DC16 dicarboxylic acid.
[0164] In step (2), the dried powdered hexadecane long-chain dicarboxylic acid product is added to the concentration crystallization tank at a ratio of 20%, the cooling rate is controlled at 1.8°C / min until the cooling temperature drops to 32°C, the stirring rate is controlled at 200 rpm, the pH value is controlled at 4.2, and the time is controlled at 4.5 hours, until large particles of hexadecane long-chain dicarboxylic acid are formed.
[0165] Step (3), transferring the large particles of long carbon chain dicarboxylic acid containing water obtained in step (2) into a disc centrifuge, and separating the water by utilizing the particle size and gravity principle to obtain large particles of long carbon chain dicarboxylic acid crystals with a water content of 8%;
[0166] Step (4): The large-particle long carbon chain dicarboxylic acid crystals with a water content of 8% obtained in step (3) are transferred to a fluidized bed dryer for drying to obtain 4.43 kg of finished large-particle long carbon chain dicarboxylic acid crystals.
[0167] After testing, the monoacid purity of the large-particle long-carbon-chain dibasic acid crystals was 98.45%, the total acid purity was 99.0%, the water content was 1.0%, and the crystal size was 10 mesh to 200 mesh.
[0168] Example 12
[0169] The preparation of DC16 dibasic acid crystals differs from that of Example 10 in that the preparation process of large-particle crystals of the hexadecane long carbon chain dibasic acid is different, specifically:
[0170] Step (1): 5 kg of refined DC16 dibasic acid was stirred and mixed with a mixed solvent of 50 L of dibutyl ether and 10 L of acetic acid in a concentration crystallization tank, and heated to 95° C. to completely dissolve the refined DC16 dibasic acid.
[0171] In step (2), the dried powdered hexadecane long-chain dicarboxylic acid product is added to the concentration crystallization tank at a ratio of 20%, the cooling rate is controlled at 1.2°C / min until the cooling temperature drops to 35°C, the stirring rate is controlled to 2000 rpm, the pH value is controlled at 3.5, and the time is controlled at 4 hours, until large particles of hexadecane long-chain dicarboxylic acid are formed.
[0172] Step (3), transferring the large particles of long carbon chain dicarboxylic acid containing water obtained in step (2) into a disc centrifuge, and separating the water by utilizing the particle size and gravity principle to obtain large particles of long carbon chain dicarboxylic acid crystals with a water content of 6%;
[0173] Step (4): The large-particle long carbon chain dicarboxylic acid crystals with a water content of 6% obtained in step (3) are transferred to a fluidized bed dryer for drying to obtain 4.82 kg of finished large-particle long carbon chain dicarboxylic acid crystals.
[0174] After testing, the single acid purity of the large-particle long-carbon chain dibasic acid crystals is 99.56%, the total acid purity is 99.80%, the water content is 1.0%, and the crystal size is 10 mesh to 200 mesh.
[0175] Figure 3 It is a powdery product of a long carbon chain dibasic acid produced according to the existing technology. Figure 3 B shows that powdered products are prone to electrostatic adsorption and adhere to the surface of the packaging bag, causing great waste in the downstream production and utilization process.
[0176] Figure 4 The large particle crystals of long carbon chain dibasic acid are prepared by the method provided in Example 1 of the present invention. Figure 4As can be seen from B, the large crystal particles do not experience electrostatic adsorption. The large-particle long-chain dibasic acid crystals prepared by the present invention can greatly reduce the waste of raw materials in downstream production, reduce downstream production costs, and have high practical application value. In addition, in downstream production, the mesh size of the large-particle long-chain dibasic acid crystals can be screened according to the specific type of solvent used in the downstream production. Specifically, molecular sieves can be used to separate large-particle long-chain dibasic acid crystals of different mesh sizes to meet different downstream production needs.
[0177] Currently, plate-and-frame filtration and flash drying are commonly used to produce powdered long-chain dicarboxylic acids. This results in very high energy consumption. Furthermore, powdered long-chain dicarboxylic acids are difficult to package and transport, and are not suitable for downstream production and use, increasing environmental investment and waste of raw materials. To address the issues of high energy consumption during the extraction process, the inconvenience of the powdered form in packaging and transporting, and downstream production and use, which in turn increases environmental investment in downstream production and use, the present invention provides a method for preparing large-particle long-chain dicarboxylic acid crystals. This improved method utilizes a concentrated crystallization process. Through an extraction process involving aging crystallization, centrifugal separation, and boiling drying and baking, energy consumption and production costs are significantly reduced, significantly lowering production costs and significantly reducing industrial production. Furthermore, the crystal size can be tailored to downstream production and use requirements, eliminating any dust side effects and material waste, reducing environmental investment in downstream production and improving packaging, transportation, and ease of use.
[0178] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.
[0179] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.
Claims
1. A method for preparing large-particle crystals of a long carbon chain dibasic acid, characterized in that: The following steps are involved: The long-chain dicarboxylic acid fermentation broth is sterilized and decolorized in sequence to obtain a solution containing long-chain dicarboxylic acid anions; adding acid to the solution containing the long-chain dibasic acid anion to perform acid precipitation crystallization to obtain a long-chain dibasic acid suspension; Add dry powdered long-chain dicarboxylic acid to the long-chain dicarboxylic acid suspension, cool the mixture to 25-36°C at a rate of 1-3°C / min, stir the mixture at 120-200 r / min for 3-5 hours, control the pH value to be 3.0-5.0 during the stirring process, and then perform aging crystallization, centrifugation, and drying in sequence to obtain large long-chain dicarboxylic acid crystal particles.
2. The preparation method according to claim 1, characterized in that Cool down to 30-32°C at 2-2.5°C / min, stir at 160-180 r / min for 3-4 hours, and control the pH at 3.5-4.2 during stirring.
3. The preparation method according to claim 1, characterized in that Based on the total amount of the long carbon chain dicarboxylic acid suspension and the dry powdered long carbon chain dicarboxylic acid, the added amount of the dry powdered long carbon chain dicarboxylic acid is 5-50%, and the purity of the powdered long carbon chain dicarboxylic acid is 70-99.9%.
4. The preparation method according to claim 1, characterized in that The molecular formula of the long carbon chain dibasic acid is: HOOC-(CH2) n -COOH, n is 8 to 20.
5. The preparation method according to claim 1, characterized in that The centrifugation is carried out by using any one of a turbine centrifuge, a tripod centrifuge, a horizontal spiral centrifuge, a disc centrifuge, a tubular centrifuge, a filter centrifuge or a sedimentation centrifuge; the drying is carried out by using any one of a boiling dryer, a fluidized bed dryer, a spray dryer or a belt dryer.
6. The preparation method according to claim 5, characterized in that The centrifugation is carried out in a turbine centrifuge, and the drying is carried out in a boiling dryer.
7. The preparation method according to claim 1, characterized in that The acid is added to make the pH of the long carbon chain dibasic acid solution be 3.5 to 5.8, and the acid is selected from sulfuric acid or hydrochloric acid.
8. The preparation method according to claim 7, characterized in that The acid addition is to add a concentrated sulfuric acid solution with a mass fraction of 93-95% to the long carbon chain sodium dibasic acid solution.
9. The preparation method according to claim 1, characterized in that The acid precipitation crystallization is to raise the temperature of the solution to 93±2° C. after adding acid and maintain the temperature for 1 to 3 hours.
10. A large particle crystal of a long carbon chain dibasic acid prepared according to the method of any one of claims 1 to 9, characterized in that: The particle size of the large particles of the long carbon chain dibasic acid crystals is 10 to 200 meshes, and the crystal density is 0.2 to 2 g / cm 3 The purity of single acid is 70% to 99.9%, the purity of total acid is 70% to 99.9%, and the water content is 0.5% to 2%.