Method for preparing polymer-grade piperylene

Abstract

The invention discloses a method for preparing polymer-grade piperylene. The method mainly comprises the following processes: 1) crude piperylene obtained by separation of a C5 fraction which is a byproduct of petroleum cracking for preparation of ethylene enters a first extractive distillation column to undergo extractive distillation, mixed materials rich in cyclopentene and cyclopentane are obtained at the top of the column, and materials rich in piperylene and an extraction agent are obtained at the bottom of the column; 2) the materials at the bottom of the column in the step 1) enter a first stripping column to remove a solvent, an extraction agent is obtained at the bottom of the column, and the extraction agent returns back to a first extraction column for recycling; 3) materials at the top of the column in the step 2) enter a dipolymer reactor to undergo a polymerization reaction, a dimerization reaction liquid enters a heavies removing column to undergo refining, heavy components such as dicyclopentadiene and the like are obtained at the bottom of the column, and materials rich in piperylene are obtained at the top of the column; 4) the materials at the top of the column in the step 3) enter a second extractive distillation column to undergo secondary extractive distillation, and a polymer-grade piperylene product is obtained at the top of the column; and 5) the materials at the bottom of the column in the step 4) enter a secondary stripping column to recover a solvent, an extraction agent is obtained at the bottom of the column, and the extraction agent returns back to a secondary extraction column for recycling.

Description

technical field [0001] The invention relates to a method for refining and separating polymerization-grade piperylene, in particular to a method for refining piperylene obtained by separating carbon five, a by-product of petroleum cracking to ethylene, to polymerization grade by using extractive distillation and dimerization reaction. Background technique [0002] In the process of producing ethylene from petroleum cracking, a considerable amount of C5 fraction is produced by-product, and the C5 fraction is rich in diolefins such as piperylene, isoprene and cyclopentadiene. These diolefins are active in chemical properties and are important resources for chemical utilization. The mixed carbon five (hereinafter referred to as crude piperylene) obtained by the carbon five separation process is composed of piperylene 65 ~ 75wt%, and the total content of cyclopentene and cyclopentane is 18 ~ 25wt%, about 2% cyclopentadiene and alkynes, a small amount of other C5 hydrocarbons and...

AI Technical Summary

Problems solved by technology

Patent US4031151 proposes to use adsorption separation technology to separate piperylene and other impurities, but the disadvantage of this method is that the surface acidity of the adsorbent has a catalytic effect on the polymerization of olefins and diolefins, and the adsorbent is easily deactivated

And this process is an unsteady material exchange process, it is difficult to achieve stable industrial operation

Images