Method and device for refining chlorine hydride byproduct and recovering trifluoromethane in production of monochlorodifluoromethane

Abstract

The invention relates to a method for refining a chlorine hydride byproduct and recovering trifluoromethane in production of monochlorodifluoromethane. Refined high-purity chlorine hydride can directly serve as a raw material for synthesizing vinyl chloride monomers; and the trifluoromethane byproduct separated in the refining process can be effectively recovered, wherein the refining of the HCl comprises the following steps of: crude separation, absorption, analysis, condensation, capture of acid mist, and adsorption; and after a F23 byproduct in the production of the monochlorodifluoromethane is separated in the absorption process in the refining of the HCl, the F23 byproduct is subjected to lossless compression and rectification to form the trifluoromethane with the purity of over 99 vol percent. By combining the recovery and comprehensive utilization of the HCl and the recovery of the trifluoromethane, the high consumption of water resources and liquid caustic soda is avoided, and the production cost of the monochlorodifluoromethane is reduced; and the effective recovery of the trifluoromethane prevents environmental pollution, and the chloroalkali, the monochlorodifluoromethane and polyvinyl chloride (PVC) can be circularly produced.

Description

technical field [0001] The invention belongs to the technical field of production of chlorodifluoromethane and polyvinyl chloride, in particular to a production process for the co-production of polyvinyl chloride (PVC) by-product hydrogen chloride from chlorodifluoromethane, especially the production of by-products in the production of chlorodifluoromethane HCl is refined for vinyl chloride monomer (VCM) synthesis. technical background [0002] In the process of producing chlorodifluoromethane by using chloroform and anhydrous hydrogen fluoride under the catalysis of antimony pentachloride, in addition to the production of chlorodifluoromethane, a large amount of HCl gas and less than 3vol% trichloromethane are accompanied at the same time Fluoromethane (F23). Separation through the HCl column, difluorochloromethane and HCl (which contains F23, and a trace amount of COF 2 , F22) are separated, hydrogen chloride is refined, recovered, and comprehensively utilized, and the r...

AI Technical Summary

Problems solved by technology

According to the method of this document, the hydrogen chloride discharged from the top of the tower is condensed to obtain liquid phase hydrogen chloride and gas phase hydrogen chloride, and the liquid phase hydrogen chloride is refluxed in the rectification tower. It can be seen that the HCl rectification tower in the method adopts external reflux, and the external The investment cost of infrastructure in the early stage of reflux is relatively high. During the operation process, due to the poor use of the potential energy of the liquid and the high consumption of cooling water and steam, the production cost is high; in addition, the method of this document does not involve the use of difluoro- Effective recovery of trifluoromethane produced by the side reaction of methyl chloride

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