Recovery method for mix waste gas of hydrogen chloride and sulphur dioxide in lipoic acid preparation

Abstract

Disclosed is a recovering method for the mixture waste gas of the chlorine hydride and the sulfur dioxide in the thioctic acid production, which belongs to the mixture waste gas recovery technical field in the thioctic acid production. The recovering method includes that the mixture waste gas of the chlorine hydride and the sulfur dioxide is introduced to a water absorption device through the pipeline; when the concentration of the chlorine hydride solution in the water absorption reaches the discharge concentration, the chlorine hydride is recovered; the purified sulfur dioxide gas after the adsorption of the chlorine hydride gas is sucked to the reactor device by the pipeline in the vacuum way and reacts with the sodium hydroxide solution in steps while the chlorine hydride gas is absorbed by the water absorption device; the reaction temperature and the PH value are respectively controlled and adjusted in steps so that the sodium sulfite solution is obtained; the sodium sulfite solution is discharged from the reactor device and fed to a centrifugal separation device for centrifugal separation, so as to obtain the seven hydrate sodium sulfite crystal; the mother liquor obtained through the centrifugal separation is fed to the reactor device again. The recovering method for the mixture waste gas of the chlorine hydride and the sulfur dioxide has the advantages of environmental protection, resource maximum utilization and saving production cost for the thioctic acid production enterprises.

Description

technical field [0001] The invention belongs to the technical field of recovery of mixed waste gas in the production of lipoic acid, and in particular relates to a method for recovering the mixed waste gas of hydrogen chloride and sulfur dioxide in the production of lipoic acid. Background technique [0002] As known in the industry, in the acylchlorination process of lipoic acid intermediates monoethyl adipate and 6-hydroxyl-8-chlorooctanoic acid ethyl ester, thionyl chloride chlorination reaction will be used, and a large amount of Hydrogen chloride and sulfur dioxide mixed waste body, the reaction equation is as follows: [0003] [0004] In the prior art, the mixed waste gas of hydrogen chloride and sulfur dioxide is usually discharged directly to the outside, which causes the following problems: first, the mixed waste gas is directly discharged to the outside, causing serious pollution to the environment; secondly, it will cause unreasonable resource utilization. wa...

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Problems solved by technology

[0004] In the prior art, the mixed waste gas of hydrogen chloride and sulfur dioxide is usually discharged directly to the outside, which causes the following problems: first, the mixed waste gas is directly discharged to the outside, causing serious pollution to the environment; secondly, it will cause unreasonable resources waste, because hydrochloric acid and sodium sulfite are widely used in the production of chemical products, and sodium sulfite has a broad market prospect as an environmentally friendly product that consumes sulfur dioxide; In the production of octanoic acid, the preparation of monoethyl adipate and the neutralization process of the hydrolysis of ethyl lipoic acid need to use a large amount of hydrogen chloride, which can save the production cost of lipoic acid

The applicant has searched, and in the existing literature, the technical revelation of comprehensive utilization of hydrogen chloride and sulfur dioxide mixed waste gas has not been retrieved, and no successful reports have been heard in the industry (lipoic acid production industry)

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