Method for separating trifluoroethylene in tetrafluoroethylene production

Abstract

The invention belongs to the filed of fluorochemical industry and provides a method for separating a trifluoroethylene in the production of a tetrafluoroethylene. The specific technical steps are as follows: a material gas on the top of a recovery tower of the tetrafluoroethylene enters directly into a distillation column; the tetrafluoroethylene and the trifluoroethylene in the material gas are separated from other components; the tetrafluoroethylene and the trifluoroethylene in the material gas aggregate on the top of the column and the rest components return to a system after the recovery tower of the tetrafluoroethylene through the bottom column; a mixture of the tetrafluoroethylene and the trifluoroethylene enters into an extraction column and the trifluoroethylene is absorbed by utilizing an extracting agent; the trifluoroethylene enters into an absorption tower with the extracting agent and is separated from an extracting liquid by steam heating in the absorption tower; the trifluoroethylene aggregates on the top of the absorption tower and then enters into a trifluoroethylene tank. The invention realizes efficient separation on the trifluoroethylene, controllability on the quality of the tetrafluoroethylene and has great potentiality in the aspect of environmental protection.

Description

technical field [0001] The invention belongs to the field of fluorine chemical industry, and relates to a method and a device for separating trifluoroethylene in a tetrafluoroethylene production process. Background technique [0002] Trifluoroethylene is a by-product of tetrafluoroethylene monomer production. At present, there are two technologies for producing tetrafluoroethylene from difluorochloromethane in industrialized use: empty tube pyrolysis and superheated steam dilution cracking. The flow process involved in the present invention belongs to superheated steam dilution cracking. [0003] Steam dilution cracking has high conversion rate, relatively few by-products, and high yield. It has become one of the important methods for producing tetrafluoroethylene in industry. At present, the steam dilution cracking method is generally used in my country for production. The main by-products of the steam dilution cracking method include trifluoroethylene, difluoromethane, h...

AI Technical Summary

Problems solved by technology

However, trifluoroethylene is very close to tetrafluoroethylene because of its boiling point, and it is difficult to separate them by simple rectification, so there has not been a good treatment method.

[0004] In the current domestic process, after the cracked gas is processed through the low boiling tower, rectification tower, tetrafluoroethylene recovery tower, raffinate tower, etc., components such as trifluoroethylene and tetrafluoroethylene return from the top of the tetrafluoroethylene recovery tower to the front Low-pressure system, such a cycle, with the accumulation of time, the content of trifluoroethylene in the system will increase, which will increase the content of trifluoroethylene in tetrafluoroethylene, and affect the performance of the polymer, making the polymer Chemical resistance, reduced dielectric properties

[0005] In order to ensure the quality of tetrafluoroethylene, when the content of trifluoroethylene in the system reaches a certain level, the method of venting the material gas at the top of the tetrafluoroethylene recovery tower is adopted to reduce the content of trifluoroethylene in the system, so that part of the tetrafluoroethylene Ethylene is vented, resulting in an increase in unit consumption, and at the same time causing certain pollution to the environment

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