Method for refining long chain dicarboxylic acid in n-alkane fermentation solution

Abstract

The invention provides a method for refining long chain dicarboxylic acid in an n-alkane fermentation solution. The method comprises: subjecting a pretreated fermentation solution and an acid solution to heat exchange by a microchannel heat exchanger respectively, rapidly mixing them to complete an acidification reaction in a microchannel heat exchanger-integrated microchannel reactor under the conditions of 15-90DEG C and 0.001-10sec, then carrying out curing for 1-60min and making the product cool to room temperature, and finally performing filtration, washing as well as drying, thus obtaining long chain dicarboxylic acid powder with ultra-high purity. The microchannel heat exchanger-integrated microchannel reactor consists of an upper cover plate, a lower cover plate, and a mixed reaction unit as well as a heat exchange unit that are stacked layer upon layer between the upper cover plate and the lower cover plate. The method provided in the invention can obtain a high-purity product with a nitrogen content less than 30ppm, and the technological process has the advantages of continuity, easy control, simplicity, employment of a microreactor technology, no amplification effect, convenience for industrial application, low production cost, and strong repeatability of results.

Description

technical field [0001] The invention relates to a microsystem and method capable of producing ultra-high-purity long-chain dibasic acids, in particular to a microchannel refining technology for purifying long-chain dibasic acids from pretreated normal alkane fermentation liquid. Background technique [0002] Long-chain dibasic acids refer to aliphatic dibasic acids with more than nine carbon atoms in the carbon chain, which can be used to synthesize a series of high-addition materials such as spices, nylon engineering plastics, nylon hot melt, high-temperature dielectrics, lubricating oils, paints and coatings. Value specialty chemicals. Its production method can adopt chemical synthesis and biological fermentation. Due to the long production process, dangerous and complicated process and high production cost of the chemical synthesis method, its industrial application is limited, and only a few foreign countries are used for production; The normal alkane fermentation metho...

AI Technical Summary

Problems solved by technology

Among the three refining methods, the solvent method has high purity and good color, and can be directly used to synthesize mid- and downstream products, but there are problems such as large amount of solvent used, solvent needs to be recycled, large equipment investment, and production safety; the aqueous phase method Product purity, appearance color and crystal particle size are worse than solvent method, but less investment, simple and safe operation process, less environmental pollution, is currently a better long-chain dibasic acid purification method; esterification method has a great impact on raw material purity , Low chromaticity requirements, high purity of the obtained product, lower yield compared with solvent method and aqueous phase method, long operation time and complicated process

[0004] CN1219530A discloses a method for refining long-chain dibasic acid. Through double-salt salting-out treatment, the refined long-chain dibasic acid product has good purity and color, but the product yield is low, and the residual long-chain dibasic acid in the salting-out mother liquor Chain dibasic acid still needs to be recycled, which increases the processing cost and the process is relatively complicated

[0005] Japanese Patent Laid-Open No. 58-193694 discloses a refining process for producing long-chain dibasic acids by fermentation. It adopts mixed solvent high-temperature extraction and cooling crystallization to separate and purify long-chain dibasic acids. The nitrogen content is less than 100ppm, but the process is complicated , high energy consumption, and cumbersome solvent recovery

[0006] CN150124A discloses a method for refining long-chain dibasic acids. The pretreated fermentation broth is acidified and crystallized, and the acidified crystallization solution is filtered through a plate and frame to obtain a dibasic acid crude product. Finally, the obtained dibasic acid crude product is obtained by scraping Membrane evaporation and short-path distillation are refined under high vacuum conditions or using organic solvents. Although the obtained long-chain dibasic acid products have high purity, there are still problems such as complex process, high energy consumption, and solvent recovery.

However, in the existing water-phase long-chain dibasic acid refining methods, the acidification process adopts the method of adding acid solution drop by drop, and the concentration of the acid solution is usually relatively high, which may easily cause the local material concentration to be too high, resulting in large particle size, The particle size distribution is wide, and the amount of soluble protein entrained in the long-chain dibasic acid particles is large; at the same time, the production process is an intermittent operation mode, and the acid solution dripping process takes a long time, the process is difficult to control, and it is easy to cause high labor intensity. , Different batches of product quality repeatability is poor and a series of problems

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