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CN-122010720-A - Process for separating glutaric acid from adipic acid byproduct

CN122010720ACN 122010720 ACN122010720 ACN 122010720ACN-122010720-A

Abstract

The invention discloses a process for separating glutaric acid from adipic acid by-product, belonging to the technical field of chemical separation. The process comprises the steps of removing a catalyst from a mixed dibasic acid solution through resin adsorption, sequentially carrying out climbing film evaporation and falling film evaporation concentration, primarily crystallizing and separating succinic acid and adipic acid from concentrated solution at 20-23 ℃ to obtain mother liquor enriched in glutaric acid, then sending the mother liquor into a multi-chamber series adiabatic evaporation crystallizer after climbing film evaporation concentration, controlling the final crystallization temperature to be 4-10 ℃ under a gradient vacuum condition, simultaneously adopting a seed crystal reflux technology, separating to obtain wet glutaric acid crystals after crystallization is completed, and drying to obtain glutaric acid products. The purity of the glutaric acid in the glutaric acid product can reach more than 95%, the yield can reach more than 90%, and the method has remarkable industrial application value.

Inventors

  • BI XINFENG
  • CUI GUOZHENG
  • Hao Cuijiao

Assignees

  • 江苏海力化工有限公司

Dates

Publication Date
20260512
Application Date
20260327

Claims (10)

  1. 1. A process for separating glutaric acid from adipic acid by-product comprising the steps of: (1) Catalyst removal The mixed dibasic acid solution is subjected to resin adsorption reaction, so that the catalyst in the mixed dibasic acid solution is adsorbed and removed by the resin, and the mixed dibasic acid solution with the catalyst removed is obtained; (2) Evaporating and concentrating Evaporating and concentrating the mixed dibasic acid solution after the catalyst removal in the step (1) to obtain a concentrated solution; (3) Preliminary crystallization Performing preliminary crystallization on the concentrated solution obtained in the step (2), cooling the concentrated solution to 20-23 ℃, crystallizing for 2-3 hours at constant temperature, and performing centrifugal separation to obtain a solid phase and a first liquid phase, wherein the first liquid phase is mother liquor enriched with glutaric acid; (4) Concentrating, crystallizing and separating glutaric acid Sending the mother solution obtained in the step (3) into a climbing film evaporator, heating, evaporating and concentrating, then sending into a multi-chamber series heat-insulating evaporation crystallizer, gradually reducing the crystallization temperature to 4-10 ℃ by adopting gradient vacuum degree control, and centrifugally separating after heat-insulating evaporation crystallization is finished to obtain wet glutaric acid crystals and a second liquid phase; (5) Drying And (3) drying the wet glutaric acid crystals obtained in the step (4) to obtain the glutaric acid product.
  2. 2. The process for separating glutaric acid from adipic acid by-product according to claim 1, wherein the content of the dibasic acid in the mixed dibasic acid solution in the step (2) is 18% -23% of the total solution, and the content of the dibasic acid in the concentrated solution after evaporation concentration is 55% -60% of the total solution.
  3. 3. The process for separating glutaric acid from adipic acid by-product according to claim 1, wherein in the step (2), firstly the mixed dibasic acid solution after the catalyst removal in the step (1) is subjected to rising film evaporation, the heating temperature of the rising film evaporation is 100 ℃ to 120 ℃, then falling film evaporation is carried out, and the heating temperature of the falling film evaporation is 140 ℃ to 155 ℃ to obtain the concentrated solution.
  4. 4. The process for separating glutaric acid from adipic acid by-product according to claim 1, wherein in the step (3), the mother liquor comprises 11% -13% of succinic acid, 69% -71% of glutaric acid and 7% -9% of adipic acid.
  5. 5. The process for separating glutaric acid from adipic acid byproduct according to claim 1, wherein in the step (4), the mother liquor obtained in the step (3) is sent into a climbing film evaporator, heated to 45-50 ℃ for evaporation and concentration, and then enters a multi-chamber series heat-insulating evaporation crystallizer, and the crystallization temperature is controlled to gradually decrease from 45-50 ℃ to 4-10 ℃ by adopting gradient vacuum degree; The heat insulation evaporator is of a six-chamber serial structure and is provided with a stirring structure, the gradient vacuum degree of the heat insulation evaporator comprises the steps that after mother liquor enters a first chamber of the heat insulation evaporator, the vacuum degree of the first chamber is controlled to be gradually reduced to minus 45kPa to minus 50kPa, after the mother liquor enters a second chamber from the first chamber, the vacuum degree of the second chamber is controlled to be gradually reduced to minus 55kPa to minus 60kPa, in the process that the mother liquor sequentially flows into a third chamber to a sixth chamber, the vacuum degree of the third chamber is respectively controlled to be gradually reduced to minus 65kPa to minus 70kPa, the vacuum degree of the fourth chamber is respectively controlled to be gradually reduced to minus 75kPa to minus 80kPa, the vacuum degree of the fifth chamber is gradually reduced to minus 85kPa to minus 89kPa, and the vacuum degree of the sixth chamber is gradually reduced to minus 90kPa to minus 95kPa, and the cooling rates of the first chamber to the sixth chamber of the heat insulation evaporator are respectively 0.5-1℃/h.
  6. 6. The process for separating glutaric acid from adipic acid by-product according to claim 5, wherein in the step (4), the stirring structure is provided in each of the first chamber to the sixth chamber of the adiabatic evaporator, and the stirring speed of the stirring structure is 800-900 rpm.
  7. 7. The process of claim 5 or 6, wherein in step (4), a part of the effluent from the last chamber of the adiabatic evaporator is returned to the second chamber of the adiabatic evaporator as seed crystals, and the seed crystal reflux ratio is 5% -15%.
  8. 8. The process for separating glutaric acid from adipic acid byproduct according to claim 1, wherein in step (4), the second liquid phase is returned to the mixed dibasic acid solution after removal of the catalyst.
  9. 9. The process for separating glutaric acid from adipic acid by-product according to claim 1, wherein in the step (5), fluidized bed drying is adopted for drying, the drying temperature is 75-95 ℃, the drying time is 3-5 min, the purity of glutaric acid in the glutaric acid product is more than 95%, and the yield is more than 90%.
  10. 10. The process for separating glutaric acid from adipic acid by-product according to claim 1, wherein in the step (2), the solid phase obtained by centrifugal separation is heated and enters into a flaker for flaking, and then is directly packaged into mixed dibasic acid.

Description

Process for separating glutaric acid from adipic acid byproduct Technical Field The invention relates to the technical field of chemical separation and purification, in particular to a process for separating glutaric acid from adipic acid byproducts. Background In the actual production of adipic acid, a mixed dibasic acid solution containing succinic acid, glutaric acid and adipic acid as a main component is produced as a by-product (waste liquid). Among them, glutaric acid is an important organic chemical raw material and intermediate, and is widely used in the pharmaceutical field, food technology, chemical industry and the like. Because the physical and chemical properties of the three dibasic acids are similar, the glutaric acid product with high purity is difficult to obtain by adopting a conventional crystallization separation method. In the prior art, CN105130790A discloses a method for separating and purifying succinic acid, glutaric acid and adipic acid in adipic acid residual liquid prepared by oxidizing cyclohexanone by nitric acid, the method comprises the steps of preliminary cooling crystallization, separating succinic acid and adipic acid by a solvent, purifying glutaric acid by a chemical method, acidifying and recycling, and finally obtaining a glutaric acid product by evaporating and drying. Although the method can effectively remove water-soluble impurities through salifying and acidifying steps, high-purity glutaric acid can be obtained theoretically, but the method has the obvious defects of (1) complex flow, more operation units and complicated process, (2) high raw material cost caused by the consumption of chemical reagents such as magnesium oxide, sulfuric acid and the like, and the generation of magnesium sulfate wastewater, and the increase of three-waste treatment cost, (3) high requirements on equipment and operation safety and potential safety hazards due to strong acid (sulfuric acid) operation. Therefore, there is a need to develop a process for separating glutaric acid from adipic acid by-products that is simple in flow, safe in operation and environmentally friendly, so as to solve the above-mentioned problems of the prior art. Disclosure of Invention In order to solve the technical problems, the invention provides a process for separating glutaric acid from adipic acid byproducts. The technical scheme of the invention is as follows: A process for separating glutaric acid from adipic acid by-product comprising the steps of: (1) Catalyst removal The mixed dibasic acid solution is subjected to resin adsorption reaction, so that the catalyst in the solution is adsorbed and removed by the resin, and the mixed dibasic acid solution with the catalyst removed is obtained; During the process of producing adipic acid, enterprises often add catalysts containing copper and vanadium, and after the catalysts react, a part of metal ions (such as copper ions and vanadium ions) remain in the final byproducts, namely the mixed dibasic acid solution. Catalyst metal ions in the mixed binary acid solution are removed in advance, so that side reactions are prevented from being caused in the subsequent high-temperature evaporation and crystallization processes, and the product quality is prevented from being influenced. (2) Evaporating and concentrating Performing rising film evaporation on the mixed binary acid solution after the catalyst is removed in the step (1), wherein the rising film evaporation temperature is 100-120 ℃, then performing falling film evaporation, and the falling film evaporation temperature is 140-155 ℃ to obtain a concentrated solution; The rising film evaporation adopts a rising film evaporator for evaporation, which is high in heat transfer efficiency compared with a common evaporator, has the advantages that materials mainly flow upwards in a heating pipe by the aid of the lifting force of steam bubbles, the heat transfer coefficient is large, the evaporation speed is high, most of moisture in mixed binary acid solution is rapidly removed by utilizing the high efficiency of the rising film evaporator when the rising film evaporator is in medium and low concentration and larger evaporation capacity, the viscosity of the materials is low at the moment, the rising film operation is suitable, the viscosity of the mixed binary acid solution is increased after the mixed binary acid solution is subjected to primary concentration, the concentration is further increased, the falling film evaporator is adopted for continuous falling film evaporation, the materials are formed at the top of the falling film evaporator and mainly flow downwards by means of gravity, the falling film evaporator is suitable for treating the materials with higher viscosity and needing deep concentration, and the thermal decomposition risk caused by overlong residence time at high temperature (150 ℃) can be better avoided; in the step (2), the concentration and viscosity of the mixed dibasic acid soluti