Method, process and apparatus for separation of ethylene glycol and 1,2-butanediol

Abstract

The invention relates to a method, a process and an apparatus for separation of ethylene glycol and 1,2-butanediol. The method includes, (1) subjecting ethylene glycol and 1,2-butanediol to reaction through acetal / ketal to produce acetal / ketal liquid product mixture correspondingly, (2) separating the acetal / ketal liquid product mixture containing ethylene glycol and 1,2-butanediol by a series of rectifying columns, (3) separating different acetal / ketal products by rectifying according to difference of boiling points of acetal or ketal, (4) respectively hydrolyzing the acetal / ketal products to obtain an ethylene glycol primary product and a 1,2-butanediol primary product, and (5) purifying the ethylene glycol primary product and the 1,2-butanediol primary product respectively by rectifying to obtain an ethylene glycol product and a 1,2-butanediol product. The purity of the ethylene glycol product can be up to 99.9% and the recovery thereof can be up to 99.5%; the purity of the 1,2-butanediol product can be up to 98.5%. By a reversible-reaction conversion method, the difficulty in separating ethylene glycol and 1,2-butanediol which are of similar boiling points and low relative volatility and are azeotropic is changed into the problem about separation of acetal / ketal products which are easy to separate relatively.

Description

technical field [0001] The invention belongs to the field of chemical distillation and separation, and relates to a separation method, process and device of 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. Alcohols can also be used in coatings, photographic developers, brake fluids and inks, etc., as solvents and media for ammonium perborate, and in the production of special solvents such as glycol ethers, which are widely used. And some studies have pointed out that ethylene glycol has great development potential in the field of liquid fuel cells in the future. my country is a big consumer of ethylene glycol, and the domestic output of ethylene glycol is far from meeting its own needs. In 2014, my country's ethylene glycol output wa...

AI Technical Summary

Problems solved by technology

[0005] 1. Patent CN101928201 discloses a purification process for the crude product of coal-based ethylene glycol. The purification process is obtained from the crude product of coal-based ethylene glycol through saponification reaction, methanol removal, hydrogenation reaction, three-tower rectification and adsorption treatment. High-purity ethylene glycol products, 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 the Yield of diol

[0006] 2. Patent CN102276418 proposes to use a mixture of ethylene glycol and 1,2-butanediol from the process of oxalate hydrogenation to ethylene glycol products, by using at least one of ZSM-5, Y-type zeolite or beta zeolite An adsorbent that absorbs 1,2-butanediol to obtain the purification of ethylene glycol. However, the recovery rate 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 CN102372596 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 tower top removes propylene glycol by extracting the ethylene glycol solution that is rich in 1,2-propanediol, and the bottom stream enters the next azeotropic rectification tower (3), and the tower bottom is rich in 1,2-butanediol ethylene glycol solution, the entrainer returns to the top of the tower after phase separation at the top of the tower, and the ethylene glycol stream is extracted into the ethylene glycol refining tower. It can also be seen that the propylene glycol and butanediol can not be removed by means of material rejection. Guarantee the high recovery rate of ethylene glycol, and at the same time, as a component with a large content, the azeotropic separation operation of ethylene glycol and the entrainer from the top of the tower is not conducive to energy saving

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