Rectifying apparatus and method of hexafluoropropylene production cracked gas

Abstract

The invention provides a rectifying apparatus of hexafluoropropylene production cracked gas, comprising a liquid residue separation column, a TFE (tetrafluoroethylene) recycling column, a light component removal column, a hexafluoropropylene rectifying column and an HFP (hexafluoropropylene) recycling column. The liquid residue recycling column is a rectifying column; the top of the liquid residuerecycling column is connected with the TFE recycling column; the bottom of the TFE recycling column is connected with the light component removal column; the bottom of the light component removal column is connected with the hexafluoropropylene rectifying column; the bottom of the hexafluoropropylene rectifying column is connected with the HFP recycling column. The invention also provides a rectifying method of hexafluoropropylene production cracked gas. The rectifying process with five rectifying columns and double compression steps is utilized herein; more reasonable process control parameters are utilized; the toxic matter octafluoroisobutylene is isolated first; other impurities are isolated step by step; the quantity of octafluoroisobutylene rectifying columns is decreased to one; lateral discharging is employed; the total quantity of the rectifying columns is decreased to five; safety level of the apparatus herein is further increased, and rectifying energy consumption is lowered.

Description

technical field [0001] The invention belongs to the field of organic chemistry, and in particular relates to a separation method and separation equipment for producing cracked gas from hexafluoropropylene. Background technique [0002] Hexafluoropropylene is a fluorine-containing material monomer, which is a colorless and odorless gas under normal conditions, with a boiling point of -29.4°C. Hexafluoropropylene is an important perfluorinated intermediate in the organic fluorine industry. It can be used to produce important fluorine-containing polymers such as polyperfluoroethylene propylene resin (F46), fluororubber (FKM), and gas fire extinguishing agent heptafluoropropane. [0003] There are many synthesis methods of hexafluoropropylene, mainly based on the pyrolysis of low-level fluorine-containing hydrocarbons with one to four carbon atoms. The methods adopted by some industrialized devices include: 1. Pyrolysis with polyfluoromethane as raw material; Fluorocarbons suc...

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Problems solved by technology

[0004] Tetrafluoroethylene and octafluorocyclobutane are pyrolysis hexafluoropropylene with a yield of more than 85%, which is suitable for industrial scale production, but the reaction mechanism is complicated, and there are many side reactions, and the product contains unconverted In addition to tetrafluoroethylene (TFE), the generated hexafluoropropylene (HFP), octafluorocyclobutane (C318), octafluorobutene, and octafluoropropane, it also contains 3℅~10% of the highly toxic substance octafluoroisobutene, due to Octafluoroisobutene has a narrow toxicity band and is highly dangerous. Its main function is to cause acute pulmonary edema. The safe concentration in the workshop is 9ppb. Therefore, the number of equipment containing octafluoroisobutene should be minimized during rectification to reduce the risk of leakage

[0005] In the prior art, the methods for separating hexafluoropropylene production gas include rectification, extraction, etc.; the extraction method is difficult to completely separate octafluoroisobutene due to the limitation of solubility; the existing rectification method and rectification equipment need to use more rectification Distillation towers are used to separate light and heavy components, but the separation efficiency is relatively low, and octafluoroisobutene is contained in some distillation towers, causing serious safety hazards

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