Method and equipment for separating propionaldehyde-water-acetic acid mixed liquid by combining azeotropic distillation and extraction distillation by saliferous mixed extracting agent

Abstract

The invention discloses a method and equipment for separating propionaldehyde-water-acetic acid mixed liquid by combining azeotropic distillation and extraction distillation by saliferous mixed extracting agent. The steps are as follows: (1) performing azeotropic distillation to propionaldehyde-water-acetic acid mixed liquid, and obtaining about 98 percent of propionaldehyde at the top of an extracting and rectifying tower; (2) extracting and separating the about 98 percent of propionaldehyde by the mixed solvent of saliferous sulfolane and glycerin, obtaining over 99.8 percent of propionaldehyde at the top of the extracting and rectifying tower, and flowing out the saliferous mixed extracting agent from a tower kettle; (3) processing the saliferous mixed extracting agent by a regeneration tower and respectively obtaining 98 percent of propionaldehyde, aqueous solution containing acid and distillate containing the extracting solvent at the top of the regeneration tower; (4) returning 98 percent of propionaldehyde into a material tank of an azeotrope tower for circulation use; and (5) dewatering the aqueous solution containing acid, returning the distillate containing the extracting solvent to a mixed solvent storage tank and circularly using the saliferous mixed extracting agent. The invention has simpler process steps, high product purity, circular utilization of the mixed extracting solvent, no waste liquid emission in the production process and low energy consumption.

Description

technical field [0001] The present invention relates to an extractive distillation process of a salt-containing mixed extractant, in particular to a process for separating propionaldehyde-acetic acid-water and propionaldehyde-acetic acid systems through azeotropic rectification and salt-containing mixed extractant extractive distillation. In particular, it relates to a salt-containing mixed solvent for extraction and rectification separation of propionaldehyde and a combined separation process of azeotropic rectification and salt-containing mixed solvent. The invention will also provide equipment for use in this method. Background technique [0002] Propionaldehyde is an important organic raw material, which can be used in a series of organic synthesis. It is the raw material for producing alkyd resin, high-efficiency and low-toxicity pesticide herbicide, insecticide, fungicide, rubber accelerator, etc. The organic products made from it are widely used in coatings, plastic...

AI Technical Summary

Problems solved by technology

[0003] Since propionaldehyde forms azeotrope with acetic acid, formaldehyde and water, the mixed product is separated by azeotropic distillation, and the reflux ratio (R) is controlled at about 10:1, which not only consumes a lot of energy, but also can only obtain about 98% of propionate. aldehyde

At present, in order to obtain high-purity propionaldehyde, more than 99% of propionaldehyde can be obtained by using calcium oxide to dry and dehydrate, and then re-distilled. However, the separation process consumes a lot of energy, and a large amount of waste liquid needs to be treated. The separation process of this method is complicated.

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