Aromatization catalyst and application thereof in highly selective preparation of p-xylene

Abstract

The invention discloses an aromatization catalyst and application thereof in the highly selective preparation of p-xylene. The aromatization catalyst consists of a carrier and active metal components, the carrier contains at least one type of mesoporous molecular sieve, antimony oxide and inorganic refractory oxide, the mesoporous molecular sieve contains lanthanum oxide, the active metal components are platinum, rhenium and a third component, and the third component is at least one of gallium, zinc, indium and tin. The aromatization catalyst is used in the reforming process of the highly selective preparation of p-xylene with paraffin, cycloparaffin, alkene, or naphtha andor the like as raw oil material, and has the advantages of high stability, high p-xylene selectivity and the like.

Description

technical field [0001] The invention relates to an aromatization catalyst and its application in the high-selectivity preparation of p-xylene as raw materials such as saturated hydrocarbons, naphthenes, olefins and naphtha. Background technique [0002] Paraxylene (PX) is one of the main basic organic raw materials in the petrochemical industry, and it has a wide range of uses in many chemical production fields such as chemical fibers, synthetic resins, pesticides, medicines, and plastics. In recent years, with the rapid increase of terephthalic acid (PTA) production capacity, the supply of p-xylene in my country is in short supply and the price remains high. The PTA industry in Asia is developing rapidly, and the supply of PX in the region has become tense. In addition, due to the constant new construction plans in the Middle East, the growth of PX is also relatively fast. [0003] Because the traditional reforming catalyst is supported by amorphous alumina, the pore dist...

AI Technical Summary

Problems solved by technology

In the preparation process of the catalyst of the present invention, in order to reduce the carbon deposition in the use process of the catalyst and improve the stability of the catalyst, it is necessary to steam the catalyst (carrier) at 400°C to 650°C, which may lead to two deficiencies : First, due to high temperature water vapor treatment may lead to the destruction of some molecular sieve crystallization, which reduces the concentration of molecular sieve pore size distribution, thereby reducing the selectivity of the reaction; in addition, due to high temperature water vapor treatment leads to partial crystallization destruction and dealumination, The amount of acid on the surface of the molecular sieve (inner surface and outer surface) is greatly reduced, and the aromatization reaction requires a strong acid center, which leads to a significant reduction in the aromatization activity of the catalyst

However, phosphorus is easily lost during use, which will affect the stability of the catalyst, and the selectivity of p-xylene cannot be kept stable.

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