Method for purifying ethylene dichloride in vinyl chloride rectification raffinate

Abstract

The invention relates to a method for purifying dichloroethane from vinyl chloride rectification residual liquid. In the method, a rectification tower, a residual liquid tank, a residual liquid pump, a vacuum distillation tower, a dichloroethane pump and a dichloroethane tank which are connected sequentially are provided, and a vacuum pump for controlling the vacuum degree of the vacuum distillation tower is also provided. The method provided by the invention is characterized in that: according to the volatility difference at different temperatures and different pressures of each component in the vinyl chloride rectification residual liquid, the rectification residual liquid from the bottom of the rectification tower is introduced to the vacuum distillation tower to remove the impurity gases in the residual liquid, so that the mass percentage of dichloroethane in the rectification residual liquid is not less than 98%, and then refined dichloroethane is conveyed to a refined dichloroethane tank for storage from the tower bottom of the vacuum distillation tower through the dichloroethane pump, thereby the purpose of dichloroethane purification is finally realized. The method provided by the invention has the advantages of less equipment, simple and reasonable process, easy implementation, simple operation, easy control and very stable production, and can achieve the purposes of safe production, energy saving, consumption reduction and quality improvement.

Description

Technical field: [0001] The invention relates to a method for purifying ethylene dichloride from the rectification raffinate produced in the production of vinyl chloride, in particular to a method for purifying dichloroethane from the rectification raffinate produced in the process of producing vinyl chloride by the calcium carbide method. Background technique: [0002] In the process of producing polyvinyl chloride by the calcium carbide method, while acetylene and hydrogen chloride react in the converter to form vinyl chloride, some high-boiling organic compounds are also produced, and the vinyl chloride is recovered through rectification, and a rectification raffinate is produced at the same time. The raffinate contains dichloroethane, vinyl chloride, nitrogen, acetylene, trichloroethylene, tetrachloroethane and other impurities, and its composition is complex, highly volatile, flammable, explosive and toxic. At present, the treatment of the rectification raffinate in pro...

AI Technical Summary

Problems solved by technology

[0004] The present invention solves the problem that there are unsafe factors in the current method for purifying dichloroethane from the rectification raffinate produced in the process of producing vinyl chloride, thereby causing safety accidents, and further provides a safe and stable production, simple and reasonable process, Method for purifying dichloroethane from vinyl chloride rectification raffinate which is easy to implement and less in investment

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