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Method for reclaiming tetrafluoroethene from tetrafluoroethene exhaust

A tetrafluoroethylene and tail gas technology, applied in chemical instruments and methods, halogenated hydrocarbon preparation, organic chemistry, etc., can solve the problem that tetrafluoroethylene tail gas cannot be treated, tetrafluoroethylene loss, increase tetrafluoroethylene unit consumption and production. Cost and other issues, to achieve the effect of large operation flexibility, low operation cost, and reduced operation cost

Active Publication Date: 2008-03-05
ZHONGHAO CHENGUANG RES INST OF CHEMICALINDUSTRY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] There are few reports about recovering tetrafluoroethylene from tetrafluoroethylene tail gas. At present, there is a method to utilize F 113 As an extractant, use extractive distillation to separate fluorine-containing gases such as tetrafluoroethylene, difluoromethane, and trifluoromethane from inert gases such as carbon monoxide, oxygen, and nitrogen, and return the fluorine-containing gases to the system for rectification to obtain tetrafluoroethylene. This method has the following obvious disadvantages: F 113 During use, it will enter the atmosphere with the exhaust gas, and the F 113 Currently banned due to serious damage to the atmospheric ozone layer, with F 113 If it is banned, the process will no longer be used, and the tail gas of tetrafluoroethylene will not be treated, and a large amount of tetrafluoroethylene will be directly discharged into the atmosphere with the tail gas, which will increase the unit consumption and production cost of tetrafluoroethylene.

Method used

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  • Method for reclaiming tetrafluoroethene from tetrafluoroethene exhaust

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Experimental program
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Effect test

Embodiment 1

[0023] After the tetrafluoroethylene tail gas is initially distilled through the degassing tower, the tetrafluoroethylene tail gas at the top of the tower enters the extractive distillation tower at a flow rate of 50kg / h. The extraction agent is acetone, and the extractive rectification is carried out according to the process parameters in Table 2. The non-condensable The gas is emptied from the top of the tower, and the extraction agent rich in tetrafluoroethylene in the tower bottom enters the desorption tower for desorption. The acetone in the bottom of the desorption tower is recycled after being cooled, and the desorbed tetrafluoroethylene is returned to the production system for re-distillation to obtain tetrafluoroethylene mono body, the recovery rate can reach 95%.

[0024] Table 2

[0025] filler

Embodiment 2

[0027] After the tetrafluoroethylene tail gas is initially distilled through the degassing tower, the tower top tetrafluoroethylene tail gas enters the extractive distillation tower with a flow rate of 150kg / h, and the extraction agent is a mixture of acetone and perfluoropropylene trimer (volume ratio 1:1). The composite solvent is extracted and rectified according to the process parameters in Table 3. The non-condensable gas is emptied from the top of the tower, and the extraction agent rich in tetrafluoroethylene in the tower reactor enters the desorption tower for desorption, and the acetone and perfluoropropylene trimer in the desorption tower reactor The composite solvent is recycled after being cooled, and the desorbed tetrafluoroethylene is returned to the production system, and the tetrafluoroethylene monomer is rectified again, and the recovery rate can reach 96%.

[0028] table 3

[0029] filler

Embodiment 3

[0031] After the tetrafluoroethylene tail gas is initially distilled through the degassing tower, the tower top tetrafluoroethylene tail gas enters the extractive distillation tower with a flow rate of 100kg / h, and the extraction agent is a mixture of acetone and perfluoropropylene dimer (volume ratio 1:1). The composite solvent is extracted and rectified according to the process parameters in Table 4. The non-condensable gas is emptied from the top of the tower, and the extraction agent rich in tetrafluoroethylene in the tower reactor enters the desorption tower for desorption, and the acetone and perfluoropropylene dimer in the desorption tower reactor The composite solvent is recycled after being cooled, and the desorbed tetrafluoroethylene is returned to the production system, and rectified again to obtain tetrafluoroethylene monomer, and the recovery rate can reach 95.8%.

[0032] Table 4

[0033] filler

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Abstract

The process of recovering tetrafluoroethylene from tetrafluoroethylene tail gas includes: initially distilling tetrafluoroethylene tail gas in a degassing tower, rectifying in an extracting rectification tower with extractant of ketone solvent or composite solvent comprising ketone solvent and perfluoro propylene polymer to evacuate inert gas from the tower top and obtain rectified component in the kettle, desorbing the rectified component in a desorption tower, and rectifying in the rectification unit of tetrafluoroethylene production to obtain tetrafluoroethylene product. The process has great operation flexibility, short technological process, facile and cheap extractant and low cost, and is suitable for industrial production.

Description

technical field [0001] The invention relates to the field of chemical industry, in particular to a method for recovering tetrafluoroethylene from tetrafluoroethylene tail gas. Background technique [0002] Chlorodifluoromethane (CHClF 2 , hereinafter collectively referred to as F 22 ) needs to go through the following units in the process of diluting and cracking with water vapor to generate tetrafluoroethylene: steam dilution and cracking unit, water removal and acid removal unit, compression unit, rectification unit, finally obtain the higher tetrafluoroethylene monomer of purity (its process The flowchart is shown in accompanying drawing 1), in the steam dilution cracking unit, F 22 Thermal cracking produces tetrafluoroethylene (C 2 f 4 ) monomer, and at the same time generate a certain amount of substances with a lower boiling point than tetrafluoroethylene, such as: difluoromethane, boiling point: -83 ° C, trifluoromethane -84.4 ° C, the reaction equation is as foll...

Claims

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Application Information

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IPC IPC(8): C07C21/185C07C17/386
Inventor 曾本忠朱德江
Owner ZHONGHAO CHENGUANG RES INST OF CHEMICALINDUSTRY CO LTD