A kind of continuous rectification separation method and device of propylene carbonate crude product

Abstract

The invention relates to a continuous rectification separation method and equipment for a propylene carbonate crude product. According to a technical scheme, the propylene carbonate crude product is fed into the middle part of a propylene carbonate rectifying column; the inner cavity of the propylene carbonate rectifying column is provided with a reflux distributor, a plurality of rhombic reaction promoting units, a feed distributor and a plurality of liquid stripping filtration disks from top to bottom; the outside of the propylene carbonate rectifying column is connected to a rectifying column overhead condenser, an A discharging line condenser, a B discharging line condenser and a rectifying column bottom reboiler respectively; the crude product is fed from the middle part of the rectifying column and subjected to sufficient gas-liquid material exchange under negative pressure and heating conditions in the column, thus achieving separation of high-purity propylene carbonate from other impurities; and the high-purity propylene carbonate product is distilled out from a product side line. The method and the equipment are advantageous in that the feeding point is at the middle of the column, amounts of rising gas and descending liquid in rectification and stripping sections are distributed more reasonably, the separating efficiency is increased, operation is simple and stable, product purity is high, and battery-grade purity requirements on the propylene carbonate are met.

Description

technical field [0001] The invention relates to the field of propylene carbonate production, in particular to a method and device for continuous rectification and separation of crude propylene carbonate. Background technique [0002] Propylene carbonate is a colorless, odorless, flammable liquid. Industrially, it is obtained by adding propylene oxide and carbon dioxide under a certain pressure, and then distilling under reduced pressure. It can be used in oily solvents, spinning solvents, olefins, aromatics extractants, carbon dioxide absorbers, dispersants for water-soluble dyes and pigments, etc. [0003] With the application of high-purity propylene carbonate in high-energy batteries and polymer industries, more and more attention has been paid to the production of propylene carbonate, but the existing separation process of crude propylene carbonate mostly adopts the method of thin film evaporator distillation, (See figure 1 ), which has disadvantages such as small pro...

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Problems solved by technology

[0005] However, the problems in this process are: first, the feed point is in the tower kettle, and the discharge point is set at a side line discharge point in the tower; The internal parts adopt a conventional structure. Fourth, the heating system adopts a falling film evaporator, and the upper line is incorporated into the vacuum line. Fifth, the cooling system adopts a top-mounted condenser, which has high operating costs and is difficult to meet the purity requirements of the battery level.

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