Method for purifying mesitylene through thermal coupling

Abstract

The invention belongs to the technical field of sym-trimethylbenzene refining, and particularly relates to a method for purifying sym-trimethylbenzene through thermal coupling, a purification part and a thermal coupling part are included, and the purification part mainly comprises a decarburization tower A, a pretreatment tower B, a light component removal tower C, a heavy component removal tower D, an extractive distillation tower E, a solvent desorption tower F and a buffer tank O; the thermal coupling part comprises the following steps: heating a 1, 2, 4-trimethylbenzene tower H, a light component removal tower C and a heavy component removal tower D by utilizing tower top gas phase material flow heat energy of a pretreatment tower B; and a composite solvent of glycerol and dimethyl sulfoxide is introduced into the extractive distillation tower E. According to the invention, through a thermal coupling means, gas phase latent heat at the tower top is fully utilized, steam condensate and heat thereof are also fully utilized, energy consumption is reduced, the cost of the adopted solvent is relatively low, the boiling point is also relatively low, and the method is suitable for industrial production. The operation temperature required in the operation process is low, the cost is reduced, the energy consumption is reduced, and the method is easy to recycle.

Description

technical field [0001] The invention belongs to the technical field of mesitylene refining, and in particular relates to a method for thermal coupling purification of mesitylene. Background technique [0002] The reformed carbon nine (C9) aromatics mainly come from the bottom oil of the xylene tower of the reforming unit of the refinery. Components such as mesitylene, dimethylbenzene and durene, these components are fine chemical raw materials with high economic added value. Mesitylene is an organic chemical raw material, mainly used for synthetic resin, 2,4,6-trimethyl-3,5-diaminobenzenesulfonic acid, mesitidine antioxidant 330, high-efficiency wheat field herbicide, 2,4 , 6-trimethylaniline, dinitro-mesitylene, vitamin E intermediate - trimethylhydroketone, polyester resin stabilizer and alkyd resin plasticizer, can also be used to produce reactive brilliant blue, K Dye intermediates such as -R3 are intermediates in the dye industry. In addition, mesitylene is also widel...

AI Technical Summary

Problems solved by technology

[0005] 1. C9 heavy aromatics distillation and freeze crystallization method, the yield of mesitylene is greater than 70%, but the energy consumption is extremely high, and most of them are not used;

[0006] 2. Alkylation method, this method can also achieve more than 90% of the separation effect of mesitylene, but the problem is that the catalyst is poisonous and pollutes the environment;

[0007] 3. Trimethylbenzene isomerization method. The main problem of this method is that the yield of mesitylene is low, and the content of mesitylene is too high, which requires technical improvement;

Existing high-purity mesitylene production technology has the following problems: 1, because mesitylene content is relatively low (5~15%) in the reformed carbon nine, and although the boiling point difference between light component p-methylbenzene and heavy component mesitylene It is greater than 2°C, but it is actually difficult to separate, resulting in high energy consumption, and the unit consumption of mesitylene reaches more than 40t / t of steam. At the same time, the investment in equipment is too large, and the competitiveness of the final device is greatly weakened; Use a single solvent, the price is high, the separation effect is not ideal, resulting in low mesitylene yield; the operating temperature is too high, the solvent is easy to coke during the separation process; in addition, the energy consumption in the solvent recovery process is too large

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