Method for separating chemical-grade isoprene

Abstract

The invention discloses a method for separating chemical-grade isoprene. The method comprises the following steps: (1) enabling pretreated C5 raw materials in which cyclopentadiene is removed to entera separating column so as to perform extractive distillation and extraction agent separation, and removing light C5 components in the materials and recovering the extraction agent; and (2) rectifyingthe materials enriched in isoprene obtained in the step (1) so as to separate and remove heavy component impurities, thereby obtaining chemical-grade isoprene on the column top. Compared with the prior art, the method disclosed by the invention has the advantages that the retention time of isoprene is shortened in the separation process, and the loss of isoprene is reduced, and meanwhile, equipment investment and separation energy consumption are reduced, and the method has obvious economic benefits.

Description

technical field [0001] The present invention relates to a separation method of chemical grade isoprene, in particular to the use of the material after pretreatment and removal of cyclopentadiene from the by-product C5 fraction of petroleum cracking to produce ethylene as raw material, using extractive distillation and solvent separation A method for the separation of chemical grade isoprene is performed simultaneously. Background technique [0002] The cracked carbon five (C5) fraction is a by-product in the process of cracking naphtha and other heavy hydrocarbons to produce ethylene, and its content is about 12% to 20% of the ethylene output. The C5 fraction is mainly composed of alkanes, monoolefins, diolefins and alkynes, among which isoprene (IP), piperylene (PD) and cyclopentadiene (CPD) are more abundant, accounting for about C5 fraction output 40% to 60% of that. Isoprene accounts for 15%-25% of the C5 fraction. It is widely used in the production of synthetic rubbe...

AI Technical Summary

Problems solved by technology

But its biggest disadvantage is that the obtained product is an azeotrope of isoprene and n-pentane, and it is impossible to obtain isoprene with higher purity. Further purification and regeneration require higher trays and larger reflux than, economically uneconomical

[0008] It can be seen that in the prior art, the problems of energy consumption, yield and purity of isoprene cannot be taken into account when preparing chemical-grade isoprene by using the C5 fraction produced by the by-product of petroleum cracking to produce ethylene.

Images