Process system and method for refining dimethyl formamide serving as extraction solvent of C5 separation device

Abstract

The invention relates to a process system and method for refining an extraction solvent dimethylformamide of a C5 separation device. The process system comprises the following steps: a solvent regeneration kettle carries out decoking treatment on the fed solvent dimethylformamide needing to be refined, and the decoked material is extracted from a gas phase, is condensed by a first condenser and then enters a crude solvent tank; conveying the crude solvent to a solvent refining tower by a crude solvent pump; the solvent refining tower, the second condenser, the reflux tank and the reflux pump of the solvent refining tower form a circulation loop, the solvent refining tower carries out reduced pressure rectification operation on a material subjected to coke removal, the material subjected to reduced pressure rectification is extracted from a gas phase and enters the reflux tank after being condensed by the second condenser, and azeotropic rectification is carried out by taking water as reflux liquid; hydrolysis inhibitor hydrocarbon substances are added into water and intermittently extracted from the tower top through azeotropy, materials subjected to azeotropic rectification are conveyed back to the solvent refining tower through a reflux pump of the solvent refining tower, and after multiple cycles, a tower kettle pump of the solvent refining tower is used for pumping out a refining solvent dimethylformamide, and a tower top extraction pump of the solvent refining tower is used for pumping out impurities.

Description

technical field [0001] The invention belongs to the technical field of preparation of dimethylformamide, an extraction solvent of a carbon five separation device, and specifically relates to a process system for refining the extraction solvent dimethyl formamide of a carbon five separation device by using vacuum distillation combined with an azeotropic distillation process and method. Background technique [0002] The cracked C5 fraction is a by-product of the steam cracking ethylene plant. Due to the difference in cracking raw materials and cracking depths, its output is generally 12% to 20% of the ethylene output, usually containing four to six carbon atoms. Alkanes, alkynes, More than 20 kinds of components such as monoolefins and diolefins. Among them, the three dienes of isoprene, piperylene and cyclopentadiene (dicyclopentadiene) are the most valuable components in the C5 fraction, and the sum of their three contents accounts for about 45% of the total. %~55%. Since...

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Problems solved by technology

[0005] Aiming at the deficiencies in the prior art, the present invention provides a process system and method for refining the extraction solvent dimethylformamide in a carbon five separation device by using vacuum rectification combined with azeotropic rectification process, so as to solve the problem of extracting dimethylformamide in a carbon five separation device. When the solvent dimethylformamide is regenerated and refined, dimethylformamide is prone to hydrolysis or the quality of the refined solvent is low

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