Method for separating byproducts C9-C10 fractions in ethylene preparation through petroleum cracking and increasing yield

Abstract

The invention relates to a method for separating and utilizing byproducts C9-C10 fractions in ethylene preparation through petroleum cracking. The method comprises the following steps: (1) carrying out depolymerization, rectification and separation on a raw material in a depolymerization and rectification tower to obtain a cyclopentadiene-enriched material on the tower top and a material of methyl cyclopentadiene from the siding; (2) feeding a bottom material in the step (1) into a decompression rectification tower for decompressed rectification so as to obtain styrene, methyl styrene, indene and remained dicyclopentadiene mixed fraction on the tower top and obtain heavy components and impurities at the bottom; (3) feeding the top mixed fraction in the step (2) into the depolymerization and rectification tower for depolymerizing and rectifying so as to obtain cyclopentadiene-enriched fraction on the tower top and obtain indene, styrene and methyl styrene mixed fraction at the bottom. According to the method, high-quality indene, styrene and methyl styrene raw materials can be obtained, and high-purity cyclopentadiene and methyl cyclopentadiene products are obtained at the same time; by adopting the process method of depolymerizing, separating and depolymerizing, the yield of dicyclopentadiene can be increased, and the indene, styrene and methyl styrene mixed material which can be directly utilized can be obtained.

Description

technical field [0001] The invention belongs to the field of petrochemical industry, and particularly relates to a method for separating and utilizing C9-C10 fractions of ethylene by-products produced from petroleum cracking, that is, the C9-C10 fractions are depolymerized, separated and other methods to obtain high-quality petroleum resin raw materials. Background technique [0002] The C9-C10 fraction is the remaining fraction after the C5 fraction and the C6-C8 fraction are separated from the by-products of naphtha or light oil cracking, accounting for about 10% to 20% of the ethylene production. The composition of C9~C10 fractions is complex, with about 150 components. This fraction mainly contains aromatics above C9, styrene, methylstyrene, dicyclopentadiene (DCPD), indene, naphthalene and other components and cyclopentadiene. Various forms of self-polymerized and interpolymerized dimers of ethylene (CPD) and methylcyclopentadiene (MCPD), among which methylstyrene and d...

AI Technical Summary

Problems solved by technology

[0005] It can be seen that the utilization of C9-C10 fractions in the prior art is only to produce CPD and MCPD by depolymerization and separation, or only the rectification and cutting of C9 raw materials are used as raw materials for petroleum resins, and the C9 raw materials are not fully utilized. and in the process of vacuum distillation C9 raw material, due to the higher concentration of DCPD, the proportion of styrene, methylstyrene and indene is relatively low, and the boiling points of DCPD and methylstyrene and indene are not much different. It is closer under reduced pressure. To obtain a higher fraction, a larger reflux ratio is required, and more methyl styrene is lost.

Images