Method for obtaining mixed aromatics by cracking of C9 and hydrogenated separation

Abstract

The invention relates to a method for obtaining mixed aromatics by cracking of C9 and hydrogenated separation. The method comprises the following steps: cracking C9 fractions in a de-heavy fractionators to remove heavy components such as colloid; carrying out first-stage low-temperature liquid phase hydrogenation on the materials subjected to colloid removal to remove easily-polymerized components such as diene; then removing monoolefine, sulfur and nitrogen by second-stage high-temperature gas phase hydrogenation; carrying out simple rectification separation on the hydrogenated C9 fractions to obtain the mixed aromatics with lower content of non-aromatic. The preparation method disclosed by the invention has the advantages of being simple, low in cost, low in requirement on equipment and suitable for scale production. The yield of the mixed aromatics disclosed by the invention is greater than 95 percent; the content of the non-aromatics in the mixed aromatics is smaller than 0.5 percent.

Description

technical field [0001] The invention relates to the technical field of chemical production, in particular to a method for obtaining mixed aromatic hydrocarbons by cracking C9 through hydrogenation separation. Background technique [0002] Since the 1990s, major ethylene plants in China have undergone capacity expansion and transformation. In recent years, some world-scale ethylene plants have been put into construction. The ethylene production capacity has grown rapidly, and the output of pyrolysis gasoline has increased significantly. The domestic ethylene production capacity will reach 2000 tons. At the same time, in order to reduce production costs, cracking raw materials tend to be inferior and heavy; in order to increase ethylene production, the cracking depth is deepened; these will lead to the deterioration of the working conditions of pyrolysis gasoline raw materials, especially the increase of carbon nine heavy pyrolysis gasoline components. Due to various reasons ...

AI Technical Summary

Problems solved by technology

[0004] Chinese patent CN104449835A introduces a method for hydrogenation of cracked C9 and above hydrocarbons. The invention uses two fixed-bed hydrogenation reactors to process materials in series, and feeds cracked C9 cuts and hydrogen to nickel-based catalysts. In the reactor of the bed layer, unsaturated components such as dicyclopentadiene, styrene and its derivatives, indene and the hydrogen in the carbon nine cuts are contacted with the bed layer containing Ni catalyst so that the Deep hydrogenation of diolefins and monoolefins, but the activity of the catalyst in this method is low, and the stability still cannot meet the requirements of industrial applications, and the aromatics content of the product is low, which is not suitable for high-quality mixed aromatics

[0007] In summary, it can be seen that the current utilization of cracked C9 hydrogen is mainly concentrated in oil adjustment components, and the hydrogenation catalyst involved is mainly used for selective hydrogenation to remove diolefins and ensure octane number. There are few studies on the separation and acquisition of mixed aromatics after full hydrogenation of all components

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