High-purity octafluorocyclobutane purification method and system

Abstract

The invention relates to a high-purity octafluorocyclobutane purification method, wherein the method comprises the following steps: step A, system cleaning: using nitrogen gas for purging a purification system, and after purging, vacuumizing the purification system; step B, low-boiling fraction removal and rectification; step C, high-boiling fraction removal and rectification; step D, finished production bottling: filling a preservation container with gas phase of a high-boiling fraction removal and rectification tower to obtain the finished product. The invention relates to a high-purity octafluorocyclobutane purification system including a primary adsorber, a low-boiling fraction removal and rectification tower, the high-boiling fraction removal and rectification tower, a membrane compressor, a first deep adsorber and a second deep adsorber. The high-purity octafluorocyclobutane purification method has simple and reliable process, and the finally obtained octafluorocyclobutane has high purity; the high-purity octafluorocyclobutane purification system has the advantages of simple structure, and has no need for large area reconstruction of conventional equipment.

Description

technical field [0001] The invention relates to the field of gas purification, in particular to a purification method and system for high-purity octafluorocyclobutane. Background technique [0002] Octafluorocyclobutane has stable chemical properties, non-toxicity, zero ozone depletion index, and low greenhouse effect potential. It is a green and environmentally friendly special gas. It has been widely used in the fields of high-voltage insulation, refrigeration, and semiconductor manufacturing in recent years. With the implementation of the Montreal Protocol and the rapid growth of the electronics industry, its role is becoming more and more important, and its usage is also increasing year by year. [0003] Octafluorocyclobutane is one of the etching or cleaning gases commonly used in semiconductor processes. With the upgrading of semiconductor devices, the requirements for the purity of etching and cleaning gases are becoming more and more stringent, and the concept of "ul...

AI Technical Summary

Problems solved by technology

[0004] The purity of the existing industrialized octafluorocyclobutane in my country is relatively low, only 99.9%. In addition to difluorochloromethane and hexafluoropropylene, it also contains a large amount of other fluorocarbons (such as HCl3, CCl2F2, CHClF2, C2HF5, C3F6, collectively referred to as "Other Organics" in the industry), and its boiling point is similar to that of octafluorocyclobutane (eight The boiling point of fluorocyclobutane is -6.04°C), and it is extremely difficult to obtain high-purity octafluorocyclobutane products with an impurity content below 10ppmv; in addition, octafluorocyclobutane is a low-pressure liquefied gas, and the saturated vapor pressure at normal temperature It is only 0.2Mpa, and the liquefaction temperature is relatively high. If negative pressure is formed in the low-temperature rectification tower, the effect of rectification and purification will not be achieved.

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