Technology for efficiently purifying glycol obtained through oxalate hydrogenation

Abstract

The invention relates to a technology for efficiently purifying glycol obtained through oxalate hydrogenation. The technology is characterized in that LNG (Liquefied Natural Gas) low-temperature liquid is subjected to heat exchange through a heat exchange unit, after the temperature of the LNG low-temperature liquid rises to a room temperature, the LNG low-temperature liquid is liquefied, and then the liquefied LNG low-temperature liquid is conveyed to a natural gas application place outside battery limit through a natural gas conveying pipeline; a glycol crude product prepared through high-temperature high-pressure oxalate hydrogenation passes through the heat exchange unit in a direction opposite to the conveying direction of the LNG low-temperature liquid through the conveying pipeline, is precooled through the heat exchange unit and is subjected to auxiliary refrigeration through auxiliary refrigeration equipment, and after the temperature of the crude product is reduced to minus 5 DEG C to 5 DEG C, the crude product is conveyed to a separation unit through the pipeline; after the temperature of the crude product in the separation unit is reduced to minus 20 DEG C to minus 40 DEG C through freezing-separation equipment, liquefied 1, 2-propylene glycol and 1,2-butanediol serve as byproducts to be separated and recycled, and the solid glycol is directly collected, or after the glycol is heated to liquid state, the liquid glycol pure product is collected. According to the technology, the impurities, namely the 1,2-propylene glycol and the 1,2-butanediol in the glycol are separated by virtue of the characteristics of difference in solidifying points, the high-purity glycol is obtained, the productivity is high, and the cold energy of LNG is fully utilized.

Description

technical field [0001] The invention relates to a process for efficiently utilizing the cold energy of LNG to purify ethylene glycol obtained by the hydrogenation of oxalate esters. Specifically, the high-grade cold energy released during the gasification of LNG is used for refining ethylene glycol by freezing and purifying by means of heat exchange. Alcohol, separate by-products such as propylene glycol and butanediol, replace the current azeotropic distillation method to purify ethylene glycol, and solve the problems of high energy consumption and low purity of ethylene glycol production. At the same time, it also helps to solve the problem of cascade comprehensive utilization of LNG cold energy. Background technique [0002] As a bulk chemical product and basic chemical raw material, ethylene glycol (EG) has broad market prospects for its development and utilization. It can be used to produce unsaturated polyester resin, polyester fiber, paint, antifreeze, ink lubricant,...

AI Technical Summary

Problems solved by technology

Such a huge amount of cold energy not only has not been used scientifically, but also destroyed the marine ecological environment and even consumed natural gas resources

my country's LNG cold energy utilization is still in its infancy, and the LNG cold energy utilization technology is still immature. It is required to find a more reasonable way of cold energy cascade utilization, increase the added value of cold energy, and reduce the cost of LNG downstream products.

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