Reactive distillation coupled novel process and device for separating liquid-phase products of ethylene glycol from coal

Abstract

The invention relates to a process and a device for separating liquid-phase products of ethylene glycol from coal. The process includes respectively removing methanol and light components, then extracting ethylene glycol stream with heavy components by the aid of a reaction column of a propylene glycol and butylene glycol removal tower and acquiring ethylene glycol products by the aid of an ethylene glycol product tower; extracting ethylene glycol stream with propylene glycol and butylene glycol from a tower top of the propylene glycol and butylene glycol removal tower, carrying out acetal / ketal reactive distillation on the ethylene glycol stream with the propylene glycol and the butylene glycol, separating acetal / ketal products and then respectively carrying out hydrolysis and purification to obtain corresponding ethylene glycol, the corresponding propylene glycol and the corresponding butylene glycol. The process and the device have the advantages that the difficulty in removing propylene glycol and butylene glycol from ethylene glycol can be effectively lowered by means of applying acetal / ketal reaction, the reflux ratio and the total number of theoretical plates can be reduced, obvious energy conservation effects can be realized, and the quality of the thermal-sensitive ethylene glycol products can be guaranteed; the yield of the ethylene glycol products can be increased, and propylene glycol and butylene glycol products or butylene glycol acetal / ketal products further can be obtained by the aid of the method.

Description

technical field [0001] The invention belongs to the field of chemical distillation and separation, and relates to a new separation process and device for a liquid-phase product of coal-based ethylene glycol. Background technique [0002] As an important basic organic chemical raw material, ethylene glycol is mainly used in the production of polyester fibers, antifreeze, unsaturated polyester resins, lubricants, plasticizers, nonionic surfactants and explosives. In addition, ethylene glycol Alcohol can also be used in coatings, photographic developer, brake fluid, and ink industries, as a solvent and medium for ammonium perborate, and for the production of special solvents such as glycol ether, etc., with a wide range of uses. Moreover, studies have pointed out that ethylene glycol has great potential for development in the field of liquid fuel cells in the future. my country is a big consumer of ethylene glycol, and the domestic ethylene glycol production is far from meetin...

AI Technical Summary

Problems solved by technology

In the existing coal-to-ethylene glycol process, in order to ensure the purity and recovery rate of ethylene glycol, many theoretical plates and high reflux ratios have to be used, which will cause the pressure drop of the ethylene glycol separation tower to be too high, and the tower The temperature of the kettle is too high, so it is easy to affect the quality of the ethylene glycol in the tower kettle, and the recovery of other high value-added glycols is not considered, and the economy of use as a refrigerant is reduced

[0005] Patent CN101928201 discloses a purification process for the crude product of coal-based ethylene glycol. The purification process obtains high purity from the crude product of coal-based ethylene glycol through saponification reaction, demethanol removal, hydrogenation reaction, three-tower rectification and adsorption treatment. However, 1,2-butanediol is removed by azeotropy with ethylene glycol, which not only causes the loss of 1,2-butanediol, a high value-added product, but also affects the production of ethylene glycol. yield

[0006] Patent CN103193594 discloses a method for separating and purifying ethylene glycol from oxalate hydrogenation liquid phase products by using a dioxane compound immiscible with ethylene glycol as an entrainer, and adopting azeotropic distillation. The liquid phase mixture passes through two light removal towers to remove low boiling point compounds such as methanol and methyl glycolate, and then enters the azeotropic rectification tower. Reflux the top of the tower, and ethylene glycol enters the ethylene glycol refining tower. With the different composition of raw materials, the recovery rate of ethylene glycol varies greatly, from 99.1% to 89.65%. At the same time, the recovery of 1,2-butanediol also bad consideration

[0007] Patent CN102372596 proposes to use azeotropic distillation to separate ethylene glycol, propylene glycol, and butanediol. After the product of ethylene glycol from synthesis gas passes through the fraction cutting tower to remove light components, it passes through the azeotropic distillation tower (2), The top of the tower removes propylene glycol by extracting an ethylene glycol solution rich in 1,2-propylene glycol, and the stream in the bottom of the tower enters the next azeotropic rectification tower (3), and the ethylene glycol solution rich in 1,2-butanediol is extracted in the bottom of the tower. Glycol solution, after phase separation at the top of the tower, the entrainer returns to the top of the tower, and the extracted ethylene glycol stream enters the ethylene glycol refining tower. The selection of the entrainer is difficult in this method, and the energy consumption of azeotropic distillation is high.

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