Method and device for separating and recycling butanone by three-tower pressure-variable rectification and heat integration

Abstract

The invention relates to a method and a device for separating and recycling butanone by three-tower pressure-variable rectification and heat integration. The method comprises the steps of: enabling raw materials to enter a dehydrating tower, obtaining water containing a small amount of organic matters from the tower bottom of the dehydrating tower, and extracting a normal-pressure azeotrope from the tower top; pressurizing the normal-pressure azeotrope and enabling the normal-pressure azeotrope to enter a butanone product tower, wherein the pressure boost increases the content of water in an azeotropic system of butanone-water, and methanol, ethanol, benzene and the like generate a minimum-boiling-point azeotrope with butanone and water; extracting a high-pressure azeotrope from the tower top, and extracting a butanone product with higher purity from the bottom of the butanone product tower; adopting a hot material stream entering from the tower top of the butanone product tower as the hot source of the dehydrating tower; and enabling the high-pressure azeotrope to enter a light component removing tower, extracting a light-component azeotrope from the tower top of the light component removing tower, obtaining a circulating material stream from the tower bottom, and enabling the circulating material stream to enter the dehydrating tower for cyclic operation. By using the method, the difficulty that butanone is separated and recycled from a complex system is solved, butanone with higher purity is obtained, the quality purity of butanone is more than or equal to 99.5%, and the energy consumption is reduced to the largest extent as a heat integration process is adopted.

Description

technical field [0001] The invention relates to a method and device for three-tower pressure-swing rectification heat integration, separation and recovery of butanone, in particular to a method for making the azeotropic composition of the system different from the methanol-ethanol-butanone-benzene-water system by using pressure changes to achieve A method for separating and recovering butanone. And in the process of pressure swing rectification, heat integration technology is used to reduce energy consumption to the greatest extent. Background technique [0002] Butanone is an excellent organic solvent and raw material for organic synthesis. It is mainly used as a solvent for various resins in the coating industry. The advantage is that it can form a solution with a lower viscosity in a certain solid component. For example, it can be used as a dewaxing solvent for refined lubricating oil, a cleaning agent for electronic components, for vegetable oil extraction and azeotropi...

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Problems solved by technology

[0005] (1) Patent 200810025463.8 discloses a technology for separating methyl ethyl ketone-water by using an alkali-soluble composite extractant to obtain 99.5wt% butanone product at the top of the tower. If the system is complex, it is necessary to reconsider the screening of compound extractants

[0006] (2) Patent 201110058579.3 discloses a method for removing water in ethyl acetate-butanone-water system by using calcium oxide, but this method only simply removes water and does not realize the separation and purification of butanone

[0007] (3) Patent 201010180392.6 discloses the separation of butanone-water by pressure swing rectification, but this patent is only limited to the butanone-water binary system, which has certain limitations

[0008] (4) Patent 200810020828.8 discloses a method for extracting methyl ethyl ketone by cross-flow liquid-liquid extraction. Polyhydric alcohol is used as the extraction agent. Since the liquid-liquid extraction and rectification is also limited to the methyl ethyl ketone-water binary system, it cannot satisfy complex systems. separation requirements

[0009] (5) Patent 200710043962.5 discloses a method for separating butanone-water by adding a salt extractant, using alkali metal oxides as the separating agent, one or more polyols as the solvent, and using acetate, nitrate or aluminum Salt is the extraction agent, this method requires high equipment, and the extraction agent and salt need to be recovered, which is difficult to recover

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