Method for purifying and removing chlorides contained in chlorine-containing industrial mixed gas and recovering light hydrocarbon

Abstract

The invention discloses a method for purifying and removing chlorides contained in a chlorine-containing industrial mixed gas and recovering light hydrocarbon, and the method comprises a pressure-swing adsorption and/or temperature swing adsorption method. An adsorptive separation system which comprises two or more than two adsorption towers filled with adsorbents and a series of program control valves absorbs and fine removes the chlorine-containing industrial mixed gas; a tail gas is respectively subjected to the following steps of: adsorption, reverse release, normal-temperature evacuation or heating flushing and filling increase in the adsorption towers under the action of the program control valves; the adsorption towers is operated according to a sequence circulating and time sequence alternating mode; the outlets positioned on the upper ends of the adsorption towers control the total content of the chlorides to be less than 5 ppm, so that a purified gas or other target product gases are obtained after the chlorides are purified and removed. The method disclosed by the invention can be used for fine purifying and removing various organic chlorides, chlorine hydride and chlorine which are contained in a dichloroethane synthetic tail gas synthesized by directly chloridizing a refining and chemical dry gas and dilute ethylene or other chlorine-containing industrial mixed gases and recovering the light hydrocarbon or the other target product gases.

Description

technical field [0001] The invention relates to a method for purifying and removing chlorides in chlorine-containing industrial mixed gas and recovering light hydrocarbons, in particular to a method for purifying and removing chlorides in dichloroethane synthesis tail gas and recovering light hydrocarbons. Background technique [0002] Chlorine-containing industrial mixed gases generally contain chlorides such as methyl chloride, ethyl chloride, and hydrogen chloride. Take the synthesis tail gas of dichloroethane as an example: in the process of direct chlorination of dichloroethane from refinery dry gas dilute ethylene and chlorine gas , because the dilute ethylene involved in the chlorination reaction carries part of ethane and a small amount of light hydrocarbon components such as methane and propane, and reacts with chlorine to form dichloroethane, and at the same time produces a small amount of monochloromethane, dichloromethane, Chloroform, monochloroethane, trichloroe...

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Problems solved by technology

[0004] Chinese patent ZL200410040545 discloses a pressure swing adsorption method for recovering vinyl chloride and acetylene from a mixed gas, which can purify and recover vinyl chloride and acetylene from a mixed gas containing vinyl chloride and acetylene, but this method is only applicable to vinyl chloride The mixed gas with acetylene does not give a solution involving the mixed gas of various organic chlorides and hydrogen chloride, and the content of vinyl chloride in the exhaust gas after purification reaches 12.9ppm, and the residual amount of chloride is still too large; at the same time This process is to concentrate and recycle vinyl chloride and acetylene together as a product gas. Its purpose is to recycle a large amount of vinyl chloride and acetylene gas in the tail gas, instead of using other gas components in the mixed gas as the target product gas, while chlorine The recovery rate of ethylene and acetylene is low. If the purified gas is discharged directly, it will not be able to meet the standard due to the high content of vinyl chloride. This process cannot be applied to the fine removal of chlorides in industrial mixed gases.

[0005] Chinese patent ZL200510022156 discloses a pressure swing adsorption separation and recovery method for mixed gas containing vinyl chloride and acetylene, which can recover vinyl chloride and acetylene in the mixed gas separately, and has increased adaptability to the content of vinyl chloride and acetylene in the mixed tail gas. However, it is only for vinyl chloride, and does not involve more separation of other organic chlorides and hydrogen chloride. At the same time, the target gas of this process is too specific, and it is for the purpose of concentrating and recovering vinyl chloride or acetylene, so it has no universal applicability.

[0006] In the above inventions, there is no provision to purify and treat various chlorides and chlorine gases such as monochloromethane, dichloromethane, trichloromethane, chloroethane, trichloroethane, hydrogen chloride, etc. produced by the chlorination reaction process of dry gas dilute ethylene Methods

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