A cracking method aimed at producing more light olefins and light aromatics from feedstock oil containing many naphthenic rings

Abstract

The invention discloses a method for cracking raw oil containing multi naphthenic rings to produce multi light olefins and light aromatic hydrocarbons and relates to a method for producing light olefins through a hydrocarbon oil raw material containing multi naphthenic rings. The method comprises: carrying out a haptoreaction on the hydrocarbon oil raw material containing multi naphthenic rings and a catalyst in a reactor, wherein the catalyst mainly comprises 5-35 wt% of heat resistant inorganic oxide, 0-65 wt% of clay, 5-50 wt% of modified mesoporous aluminosilicate material and 15-60 wt% of molecular sieve; and the molecular sieve comprises a beta molecular sieve and an MFI molecular sieve, and the weight ratio of the molecular sieve to the MFI molecular sieve is not less than 1 / 3. By adopting the method, the yield of propene and isobutene is high, and the BTX proportion in gasoline fraction aromatic hydrocarbon is high.

Description

technical field [0001] The invention relates to a catalytic cracking method for petroleum hydrocarbons, in particular to a catalytic cracking method for producing propylene and isobutylene from raw oil containing more naphthenes and single-ring aromatics. Background technique [0002] Catalytic cracking is an important method for producing low-carbon olefins such as propylene and butene. It is generally believed that the method of adding molecular sieves with MFI structure to the catalyst can re-crack paraffins or olefins with a low degree of branching (normal or only one branch) in catalytic cracked gasoline fractions, and can produce more ethylene, Propylene and other low carbon olefins. As reported in US3758403, adding ZSM-5 to the Y-type molecular sieve catalyst can increase the yield of light olefins. [0003] CN1057408A discloses a cracking method using a cracking catalyst containing high-silica zeolite, based on the total weight of the catalyst, consisting of 10-30%...

AI Technical Summary

Problems solved by technology

During the conversion process of naphthenic rings, there are many reactions such as ring-opening cracking and dehydroaromatization. Therefore, its reaction performance is different from that of paraffins. It is common to use existing methods to convert feedstock oils containing more naphthenic rings. The problem of low yield of propylene and butene

In addition, for some low-quality heavy oil raw materials, because they contain more polycyclic aromatic hydrocarbons, they are not suitable for direct use as raw materials for catalytic cracking. The current common practice is to carry out hydrogenation treatment, but hydrogenation is not suitable for the production of light olefins, and these The hydrotreated product contains a large number of naphthenic rings, which can be converted to produce low-carbon olefins by existing methods, and there is also the problem that the yield of propylene and butene is not high

In addition, the conventional catalytic cracking method processes raw oil containing more naphthenic rings, the concentration of low-carbon olefins in the cracked gas is not high, and the concentration of BTX in the catalytic cracking gasoline fraction or light gasoline fraction aromatics is not high

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