Hydrogenation method for producing aromatics extraction raw material

Abstract

The invention relates to a hydrogenation method for producing an aromatics extraction raw material. The method adopts two hydrogenation units and performs different reactions at different temperatures, wherein the first hydrogenation unit is filled with protective agents with different specifications in a graded loading mode; the protective agents are mainly used for removing diene, delaying the coking of the top part of a catalyst bed layer and prolonging the running period of a device at a low temperature; the second hydrogenation unit is filled with a hydrorefining catalyst for desulfurization, denitrification and alkene saturation at a high temperature and alkene saturation as little as possible. The hydrogenation method broadens the source of the aromatics extraction raw material; through the method provided by the invention, gasoline fractions with high diene value content and high impurity content can be converted; and the obtained product has the nitrogen content and the sulphur content of less than 1 mu g / g, and the bromine value of less than 0.5 gBr / 100g so as to meet the requirement of an aromatics extraction device on feeding.

Description

Technical field [0001] The invention belongs to a method for refining hydrocarbon oil in the presence of hydrogen, and more specifically, it is a hydrogenation method for processing high diene gasoline fractions. The product obtained by the method is a raw material for aromatic extraction. Background technique [0002] With the continuous development of the petrochemical and textile industries, the world's demand for aromatic products continues to grow, especially for benzene and xylene. For a long time, the output of my country's aromatic products has been unable to meet demand. At present, most of the sources of aromatics are gasoline produced by the catalytic reformer unit of the refinery and pyrolysis gasoline produced by the ethylene unit. The method of separating aromatics from these two gasolines is mainly solvent extraction. Therefore, how to broaden the source of aromatics extraction raw materials is a problem that needs to be solved. [0003] Catalytic cracking (DCC) pr...

AI Technical Summary

Problems solved by technology

However, aromatic products have very strict restrictions on impurities such as sulfur and nitrogen. It is usually required that the sulfur content in the product is less than 1 μg / g, and the nitrogen content is less than 1 μg / g, and the extraction process cannot remove impurities such as sulfur and nitrogen. Therefore, it is necessary to remove DCC Impurities such as sulfur and nitrogen in gasoline provide qualified raw materials for aromatics extraction units

[0004] According to the existing hydrofining technology, there are many problems in directly desulfurizing and denitrifying DCC gasoline: due to the high diene content in DCC gasoline, it is easy to polymerize and coke at the top of the catalyst bed, resulting in an increase in the pressure drop of the reactor. Greatly affect the long-term stable operation of the device

However, the high content of dienes and gums makes this gasoline fraction extremely unstable

[0007] CN1990830A discloses a coker gasoline hydrofining method, the method is first contacted with a hydrogenation protecting agent at a low temperature, and then contacted with a hydrofinishing catalyst at a high temperature, the olefin content in the refined gasoline fraction is less than 1% by volume, The sulfur content is less than 300μg / g, and the nitrogen content is less than 2μg / g, both of which can meet the feed requirements of the reforming prehydrogenation unit and steam cracking ethylene unit. This process can delay the pressure drop of the reactor and prolong the refueling of coker gasoline. Hydrogen unit operating cycle, but the content of sulfur and nitrogen in coked gasoline is still high after treatment, and further treatment is needed

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