A method for completely removing acidic substances in crude vinyl chloride gas

Abstract

The invention relates to a method for completely removing acidic substances in crude vinyl chloride gas. The device used includes two parts: hydrogen chloride absorption and double-tower alkali washing. The process is as follows: crude vinyl chloride gas enters the hydrogen chloride combined absorption tower, is absorbed by dilute hydrochloric acid and concentrated hydrochloric acid respectively, and then enters the dilute hydrochloric acid tower, and completes in the dilute hydrochloric acid tower. Complete absorption of hydrogen chloride; the crude vinyl chloride gas from the top of the dilute hydrochloric acid tower enters the alkali washing tower I, where the alkali liquid is used to wash the crude vinyl chloride gas, then enters the alkali washing tower II, and then uses high-concentration The alkaline solution washes the crude vinyl chloride gas to ensure that the acidic substances therein are completely removed; the method of the present invention can completely absorb the acidic substances in the crude vinyl chloride gas from the converter to form hydrochloric acid with a concentration of 29% to 31%wt , reducing the loss of vinyl chloride and reducing the harm to subsequent treatment equipment; the two-stage alkali washing can not only reduce the consumption of alkali and fresh water, but also reduce the amount of discharged wastewater, which greatly reduces the pollution to the environment.

Description

Technical field: [0001] The invention relates to a method for removing acidic substances in mixed gas produced by calcium carbide acetylene hydrochlorination, in particular to a method for completely removing acidic substances in crude vinyl chloride gas, belonging to the technical field of gas purification. Background technique: [0002] Polyvinyl chloride (PVC) has excellent comprehensive properties and is one of the five general-purpose synthetic resins, widely used in various fields of the national economy. In the past 10 years, my country's PVC production capacity has increased rapidly, and by the end of 2012, the production capacity had reached 24 million tons, accounting for about half of the world's total production capacity. In view of the resource characteristics of rich coal and poor oil in our country, most domestic PVC manufacturers use the calcium carbide method to produce vinyl chloride. The main reaction is that acetylene and hydrogen chloride are catalyzed b...

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to overcome the shortcoming of prior art, provide a kind of method of completely removing the acidic substance in the crude vinyl chloride gas, to completely remove acidic substances such as remaining hydrogen chloride and carbon dioxide in the crude vinyl chloride gas that the converter comes out, solve Common problems in PVC production enterprises such as high loss of vinyl chloride VCM, waste of lye, and equipment corrosion

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