System and method for rectifying and purifying dimethyl oxalate synthesized through carbonylation of glycol from coal

Abstract

The invention relates to a system and method for rectifying and purifying dimethyl oxalate synthesized through carbonylation of glycol from coal. Through the system and method, the purity of the dimethyl oxalate product can be imprved, energy consumption is reduced, and the production cost is saved. The system comprises a dimethyl oxalate feeding heat exchanger and a vacuum rectification tower communicating with the dimethyl oxalate feeding heat exchanger, wherein a reboiler is arranged at the bottom of the tower, a tower-top condenser communicates with the top of the vacuum rectification tower through an evaporation vapor outlet, and the tower-top condenser communicates with a reflux tank and a tail cooler separately; the reflux tank communicates with a reflux pump, the reflux pump communicates with the top of the vacuum distillation tower and a tower-top extraction flow regulating valve, and the bottom of the rectification tower communicates with a heavy component discharge pump; andthe heavy component discharge pump passes through the dimethyl oxalate feeding heat exchanger and communicates with a material outlet of the tower through a pipeline and a tower liquid level regulating valve, a reflux flow regulating valve is arranged on the outlet pipeline of the reflux pump so as to remove light component impurities in a dimethyl oxalate mixed liquid and obtain a high-purity dimethyl oxalate intermediate product. Through vacuum operation, the boiling points of the components are reduced, the consumption of medium pressure steam is reduced, and the cost is reduced; and the tower components and the tower-top light components are taken out continuously, heat and materials are recycled and utilized effectively, and no outer emission of the materials occurs.

Description

technical field [0001] The invention belongs to the field of coal-to-ethylene glycol chemical industry, and in particular relates to a rectification and purification system and method for carbonylation of coal-to-ethylene glycol to synthesize dimethyl oxalate, which can improve the purity of dimethyl oxalate products, reduce energy consumption and save production costs . Background technique [0002] Ethylene glycol is an important chemical raw material, mainly used as a raw material for solvents, antifreeze and synthetic polyester resins. At present, ethylene glycol is mainly prepared by direct hydration of ethylene oxide. Since the preparation of ethylene oxide is based on ethylene, mass production mainly depends on petroleum resources. However, my country's overall energy characteristics are rich in coal, gas, and low in oil. Therefore, it is of great significance to efficiently convert coal into chemical raw materials such as ethylene glycol and reduce the dependence o...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problem of the low purity of the target product dimethyl oxalate caused by the carbonylation side reaction in the coal-to-ethylene glycol production process existing in the above-mentioned

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