Technique for coproducing polyvinyl chloride from by-product hydrogen chloride of trichloroethylene

Abstract

The invention relates to a production technology of trichloroethylene, with HCL as by-product and polyvinyl chloride as co-product, which is applicable to the corporations for producing chlor-alkali,calcium carbide process (PVC) and trichloroethylene, aiming at solving the difficult problem of recycling and processing byproduct HCL in the existing trichloroethylene production. A refining processis done to the HCL; the separated chlorohydrocarbon is directly sent to the distillation system of trichloroethylene; the HCL gas after the refining process can meet the technology requirement for HCLof VCM synthesis in PVC production in terms of gas purity, chlorohydrocarbon content and pressure; after five steps of chlorohydrocarbon rough separation, effective collection, adsorption in adsorbing tower, and so on, the HCL meets technology requirement; the qualified HCL, after being cooled and pressured, is sent to carry out VCM synthesis, which solves the problem of the HCL retraction mixingwith chlorohydrocarbon, reduces production cost of trichloroethylene, prevents environment pollution and achieves circulation production of caustic soda and trichloroethylene PVC.

Description

1. Technical field [0001] The invention belongs to the technical field of trichlorethylene and polyvinyl chloride production, in particular to a new production process for the co-production of trichlorethylene by-product hydrogen chloride and polyvinyl chloride. Refining and transporting the by-product HCL in the production of trichlorethylene, especially the new process of using HCL in the synthesis of vinyl chloride monomer (VCM). 2. Background technology [0002] In the process of producing trichlorethylene by pyrolysis of tetrachlorethylene, in addition to producing trichlorethylene, a large amount of HCL gas is accompanied at the same time. Trichlorethylene can be separated from HCL by means of rectification, but a small amount of chlorinated hydrocarbons are often entrained in the HCL gas after separation, and the treatment of the entrained small amount of chlorinated hydrocarbons HCL will determine the production cost of trichlorethylene and the impact on trichlorethy...

AI Technical Summary

Problems solved by technology

Since the chlorinated hydrocarbons that are simply separated contain a large amount of water (500-1000PPM) and cannot directly enter the rectification system of trichlorethylene, they must undergo secondary treatment before they can enter the rectification system of trichlorethylene. Therefore, from a technological point of view, A treatment process must be added; and the amount of dilute hydrochloric acid with a concentration of about 10% to 20% is huge. For example, based on the calculation of an annual output of 10,000 tons of trichlorethylene, this method will produce 15,000 to 30,000 tons of dilute hydrochloric acid with a concentration of about 10% to 20%. , not only this process needs to consume a lot of water, but also the follow-up treatment of such a large amount of dilute hydrochloric acid is very difficult. If it is sold as a product, it is difficult to find market space because the concentration is too low. If it is discharged directly, it will cause serious pollution to the environment. If Storage is not realistic at all, and if neutralized with alkali, a large amount of alkali will be consumed

So far, there is no better treatment method for HCL, a by-product of trichlorethylene production in China