Ethylene Cracking Raw Material by Hydrogenation of Light C5 Distillate

Abstract

The invention provides a method for preparing ethylene cracking raw materials by hydrogenating light C5 fractions. The method comprises the steps that the hydrogenated light C5 fraction raw materials are subjected to hydrogenation reaction via a hydrogenation catalyst fixed bed in the presence of hydrogen to convert unsaturated hydrocarbons in the light C5 fraction raw materials to saturated hydrocarbons, and part of the hydrogenation products returns as solvents and passes through the hydrogenation catalyst fixed bed together with the raw materials after being mixed with the raw materials, wherein the feeding weight ratio of the latter to the former is 1:(6-10); and the hydrogenation products as the solvents are desulfurized by a desulfurizer fixed bed before being mixed with the raw materials, wherein the desulfurizer is a Cu<2+> modified Y type molecular sieve, and the content of Cu<2+> in the molecular sieve is 1.6-4.8wt%. The method has the advantages that the light C5 fraction materials with content of active sulfides being about 0.002wt% can be hydrogenated; and the desulfurizer and the hydrogenation catalyst can guarantee long-period operation.

Description

technical field [0001] The present invention relates to a method for hydrogenation of C5 cuts containing unsaturated hydrocarbons, in particular to a method for preparing raw materials for cracking ethylene by hydrogenation reaction of C5 cuts containing unsaturated hydrocarbons and active sulfides . Background technique [0002] The traditional raw material for industrial steam cracking to ethylene production is naphtha. With the increasing shortage of petroleum resources, light hydrocarbon resources mainly composed of C4-C6 produced in the petroleum refining process are also increasingly used. Compared with naphtha, light hydrocarbons can obtain higher yields of ethylene and propylene due to their lighter components. However, this light hydrocarbon material contains relatively high unsaturated hydrocarbons, mainly including olefins, dienes and a small amount of alkynes. Under the high temperature environment of the cracking furnace, unsaturated hydrocarbons will undergo p...

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Problems solved by technology

[0007] However, appropriate high temperature is beneficial for the desulfurization of modified molecular sieves, and as mentioned above, light carbon five fractions contain a relatively large amount of 1,3-butadiene, iso Pentadiene, cyclopentadiene, and 2-butyne and other diolefins and alkynes, and metal ions will catalyze and accelerate the polymerization of diolefins and alkynes, and the generation of oligomers in the desulfurization process will be unavoidable

These oligomers will accumulate on the modified molecular sieve, cover the catalytic active sites on the surface of the modified molecular sieve and block the pores of the molecular sieve, and the modified molecular sieve will soon lose its catalytic and adsorption functions for sulfides

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