Automatic continuous thymol crystallization system and method

Abstract

The invention provides an automatic continuous thymol crystallization system which comprises a feeding tank, a crystallizer, a temperature control device, a crystallized material tank, a centrifugal machine, a crystal recovery device, a mother liquor recovery device, a thymol content analysis unit and a waste liquor recovery tank which are connected with a control system, an outlet of the feeding tank is connected with a crystallization point measuring unit and an inlet of a crystallizer through pipelines, an outlet of the crystallizer is sequentially connected with a post-crystallization material tank and a centrifugal machine through pipelines, an outlet of the centrifugal machine is connected with a crystal recovery device and a mother liquor recovery device through pipelines, and an outlet of the crystal recovery device is connected with a thymol content analysis unit through a pipeline. An outlet of the mother liquor recovery device is connected with an inlet of the feeding tank, the thymol content analysis unit and the waste liquor recovery tank through pipelines; each pipeline is provided with one or more of a valve, a flow monitoring meter or a pump which are controlled to be opened and closed. The automatic continuous crystallization system provided by the invention realizes automation and continuity of multiple crystallization and purification processes, and is simple and efficient in system setting and convenient to operate.

Description

technical field [0001] The invention relates to the technical field of thymol production, in particular to an automatic continuous crystallization system and method of thymol. Background technique [0002] Thymol (5-methyl-2-isopropylphenol) is a colorless crystal or a colorless crystalline powder at room temperature, with the special aroma of thyme or thyme, and is often used in the fragrance industry to make flavors, fragrances and as Raw material for the synthesis of L-menthol. In addition, thymol is widely used in the fields of medicine, daily chemicals and antioxidants. [0003] Chemical synthesis of thymol usually adopts the process route of m-cresol for Friedel-Crafts alkylation. The crude product contains isomers and intermediate impurities, which need to be purified to obtain high-purity thymol to meet downstream needs, especially It is a high-purity requirement as a raw material for synthetic menthol. [0004] The prior art method for separating and purifying th...

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Problems solved by technology

[0004] The methods for separating and purifying thymol in the prior art mainly adopt organic solvent recrystallization or organic solvent low-temperature crystallization, for example, the purification process disclosed in CN106008169A is to obtain thymol finished product through vacuum distillation, petroleum ether or n-hexane recrystallization , the refining process disclosed in CN108911951A adopts low-temperature crystallization of organic solvents. The process of these methods is cumbersome, requires the use of a large amount of organic solvents, and mostly is intermittent operation, which is not conducive to large-scale industrial application

[0005] CN112811988B discloses a method for the continuous purification of thymol, which uses water instead of organic solvents as the crystallization solvent, increases the crystallization temperature, reduces the energy consumption of crystallization and simultaneously realizes the continuous purification of thymol, but the process of continuous purification is relatively complicated and the degree of automation Low, it is necessary to manually measure the content of the mother liquor and crystals after the previous purification and crystallization, and then put it into the feed tank 1 for the next crystallization, which is not conducive to the realization of continuous industrial production, and the production efficiency is low, and the obtained thyme The highest purity of phenol is only 99.37%, which needs to be further perfected and improved

[0006] Both patent CN102643169A and patent CN103922898B disclose a method for separating and purifying substances by continuous crystallization. Their common feature is that multiple crystallizers are set up, and the materials are put into the next crystallizer immediately after the last crystallization is completed. Re-crystallization, although the purpose of continuous production has been achieved, but at least two or more crystallizers need to be configured in series, and the number of crystallization times actually required cannot be flexibly selected or adjusted, and can only be configured according to the number of crystallizers configured at the time of initial equipment installation to crystallize

In addition, due to the configuration of multiple crystallizers, the device occupies a large area and has a complex structure, which is not conducive to reducing costs

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