C8 aromatic hydrocarbon isomerization catalyst, preparation method and application thereof

Abstract

The invention relates to a C8 aromatic hydrocarbon isomerization catalyst which comprises a rare earth-modified molecular sieve, a halogen-modified inorganic melting-resisting oxide and at least one VIII-family precious metal, wherein the molecular sieve is an EUO molecular sieve, the weight ratio of the rare earth-modified molecular sieve to the halogen-modified inorganic melting-resisting oxideis 10:90-90:10, in the catalyst, the content of the VIII-family precious metal is 0.1-10 percent by weight, in the rare earth-modified molecular sieve, the mass content of the rare earth oxide is 0.5-60.0 percent, and in the halogen-modified inorganic melting-resisting oxide, the mass content of the halogen is 0.5-20.0 percent. Compared with the prior art, the catalyst can ensure that the dimethylbenzene is isomerized and ethylbenzene is selectively transformed into paraxylene when used in C8 aromatic hydrocarbon isomerization and the concentration of the paraxylene in the catalyst in dimethylbenzene reaches or approaches a thermodynamic equilibrium value, and has high yield of the dimethylbenzene.

Description

technical field [0001] The present invention relates to C 8 Catalyst for the catalytic conversion of aromatic hydrocarbons and its preparation method and application, especially a catalyst for the isomerization of o-xylene and m-xylene into p-xylene, its preparation method and application, and also relates to C 8 Conversion of ethylbenzene in aromatics. Background technique [0002] In the petrochemical production process, C obtained from various processes 8 Among aromatic hydrocarbons, in addition to p-, m-, and o-xylene, ethylbenzene is also contained. Using this as a raw material, p-xylene products can be obtained through combined operations such as isomerization, rectification and adsorption separation. Since the boiling points of ethylbenzene and xylene are very close, the separation is difficult, resulting in the accumulation of ethylbenzene in the recycle stream of the combined unit, resulting in an increase in the flow rate of the combined isomerization unit, and ...

AI Technical Summary

Problems solved by technology

A potential problem in the above prior art is that the ethylbenzene in the raw material is converted into benzene and C through dealkylation. 2 fraction, the benzene and C must then be 2 Fractions are separated from process streams or converted

Although this method can increase the p-xylene equilibrium concentration in the product, the method causes many xylene losses, and the product yield decreases.

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