Pre-separation method of C5 diene for distilling off methyl butane for two times

Abstract

The invention discloses a pre-separation method of C5 diene for distilling off methyl butane for two times; two rectifying towers are used for distilling off methyl butane in C5 for two times, wherein the first distilling is carried out before thermal dimerisation reaction, and the second distilling is carried out after the thermal dimerisation reaction the method comprises four steps: (1) pre-dehydrogenation; (2) distilling off the methyl butane for the first time; (3) thermal dimerisation reaction; (4) distilling off the methyl butane for the second time. Compared with the prior art, the method has the advantages that: the methyl butane is respectively distilled off before and after the thermal dimerisation reaction, the disadvantages that the methyl butane has large loss in the pre thermal dimerisation reaction and the content of cyclopentadiene in methyl butane material flow is hard to control in the latter thermal dimerisation reaction are overcome, thereby better realizing to fully recovering the methyl butane and to effectively control the content of the cyclopentadiene in methyl butane material flow.

Description

technical field [0001] The present invention relates to a kind of separation method of petroleum cracking C5 fraction, specifically, relate to a kind of C5 raw material pre-separation method of distilling out isoprene twice with two rectification towers, wherein once steaming out is in Before the thermal dimerization, another distillation is after the thermal dimerization. Background technique [0002] The cracked C5 contains isoprene, piperylene and cyclopentadiene, the total amount of which is about 40-60%. The recovery and utilization of these dienes is of great significance for the utilization of petroleum resources and the improvement of economic benefits. [0003] The existing C5 separation technology adopts extraction and rectification to prepare isoprene, and the common solvents are dimethylformamide, acetonitrile or N-methylpyrrolidone, etc. [0004] In order to reduce the load of extractive rectification, C5 raw materials are usually pre-separated before entering...

AI Technical Summary

Problems solved by technology

The disadvantage of the pre-thermal dimerization process is: the material from which isoprene has not been separated enters the thermal dimerization reactor, and the concentration of isoprene in the material is high. When cyclopentadiene is dimerized into dicyclopentadiene, The isoprene in the material is easy to undergo copolymerization reaction with cyclopentadiene to survive the copolymer of cyclopentadiene and isoprene, so the loss of isoprene is relatively large

The disadvantage of the post-thermal dimerization process is: in the case of not converting cyclopentadiene into dicyclopentadiene, all the isoprene contained in the material must be distilled out, because the concentration of cyclopentadiene in the material is large, it is easy to As the isoprene is distilled from the top of the tower, it is difficult to control the cyclopentadiene content in the isoprene stream at the top of the tower, and it is more difficult to control the cyclopentadiene content in the isoprene product in the subsequent extractive distillation

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