New method, process and device for the separation and purification of ethylene glycol and 1,2-butanediol by reactive distillation

Abstract

The invention relates to a separation method, technique and device of ethylene glycol and 1,2-butanediol. The method comprises the following steps: reacting a diol mixture and aldehyde or ketone in a reaction rectification tower by acetal or ketal reversible reaction to generate an acetal / ketone mixture, rectifying to separate the acetal / ketone mixture, and carrying out reaction, rectification and hydrolysis to obtain the high-purity ethylene glycol and 1,2-butanediol products. By using the technique for separation and purification, the purity of the main product ethylene glycol can reach 99.9% or above, the recovery rate can reach 99.5% or above, and the purity of the 1,2-butanediol product can reach 98.5% or above. By using the reaction rectification method, the difficulty in separating azeotropic ethylene glycol and 1,2-butanediol with approximate variable boiling point and low relative volatility becomes the problem of separation of the separable acetal / ketone product, thereby effectively implementing the high-efficiency separation on the ethylene glycol and 1,2-butanediol.

Description

technical field [0001] The invention belongs to the field of chemical distillation and separation, and relates to a separation method, process and device for ethylene glycol and 1,2-butanediol. 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 meeting its own need...

AI Technical Summary

Problems solved by technology

[0005] 1. Patent CN 101928201 discloses a purification process for the crude product of coal-to-ethylene glycol. The purification process is through saponification reaction, demethanol, hydrogenation reaction, three-tower rectification and adsorption treatment, from the crude product of coal-to-ethylene glycol High-purity ethylene glycol products are obtained, but 1,2-butanediol is only removed by azeotropy with ethylene glycol, which not only causes the loss of 1,2-butanediol, a high value-added product, but also affects Ethylene glycol yield

[0006] 2. Patent CN 102276418 proposes to use a mixture of ethylene glycol and 1,2-butanediol for the process of hydrogenation of oxalate to ethylene glycol products, by using at least ZSM-5, Y-type zeolite or β-zeolite An adsorbent that adsorbs 1,2-butanediol to obtain the purification of ethylene glycol, however, the recovery of ethylene glycol is not indicated, and the recovery and utilization of 1,2-butanediol is not involved

[0007] 3. Patent CN103193594 discloses a method for separating and purifying ethylene glycol from the liquid phase product of oxalate hydrogenation by using a dioxane compound immiscible with ethylene glycol as an entrainer and using azeotropic distillation method, the liquid phase mixture passes through two light removal towers to remove low-boiling compounds such as methanol and methyl glycolate, and then enters the azeotropic rectification tower. The boiling agent returns to the top of the tower, and ethylene glycol enters the ethylene glycol refining tower. With the composition of raw materials, the recovery rate of ethylene glycol varies greatly in this method, dropping from 99.1% to 89.65%. At the same time, 1,2-butanediol Recycling is also poorly considered

[0008] 4. Patent CN 102372596 proposes to use azeotropic distillation to separate ethylene glycol, propylene glycol, and butanediol. After the synthesis gas ethylene glycol product 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-propanediol, and the stream in the bottom of the tower enters the next azeotropic rectification tower (3), and the extraction in the bottom of the tower is rich in 1,2-butanediol Ethylene glycol solution of alcohol, 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. It can also be seen that propylene glycol and butanediol are removed by means of material rejection. The high recovery rate of ethylene glycol cannot be guaranteed. At the same time, as a component with a large content, ethylene glycol and the azeotropic separation from the top of the column are not conducive to energy saving

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