Reforming catalyst and application in high selectivity production of para-xylene of the same

Abstract

The invention discloses reforming catalyst and the application in the preparation of para xylene reforming high selectivity and taking saturated hydrocarbon, cycloparaffinic hydrocarbon and naphtha as the raw material. The carrier of the catalyst includes mesoporous molecular sieve, antimony oxide and inorganic melt-resistant oxide, wherein, the mesoporous molecular sieve includes 0.5 wt percent to 10.0 wt percent of phosphorus pentoxide. The surfaces of the antimony oxide and the molecular sieve included in the catalyst are contacted to facilitate the strong acid position on the surface of the molecular sieve to be intoxicated, so as to lower the reaction activity center with poor selectivity, and to maintain a passage reaction site with high selectivity; meanwhile the invention adopts phosphorus pentoxide modified molecular sieve to adjust the internal surface of the molecular sieve, particularly to adjust the size of the passage of the molecular sieve, so as to further contract the size of the passage to restrain the generation of the nonideal products of ortho xylene and meta xylene, and to improve the selectivity of the ideal product para xylene.

Description

technical field [0001] The invention relates to a reforming catalyst and its application in high-selectivity preparation of p-xylene by reforming saturated hydrocarbons, naphthenes, olefins, naphtha and the like as raw materials. Background technique [0002] P-xylene is an important organic chemical raw material, a by-product of naphtha reforming process, mainly used in the synthesis of terephthalic acid or dimethyl terephthalate, dimethyl terephthalate and ethylene glycol The polyester obtained by the reaction has excellent properties and is widely used as a raw material for fibers and plastics. With the sharp increase of the global demand for polyester, the production of p-xylene will increase rapidly. According to the forecast results of the British TECNON consulting company in December 1999, the absolute growth value of the global demand for p-xylene during the period from 2001 to 2007 It is 7.042 million tons, and the annual growth rate is expected to be around 5.6%. ...

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, since the purpose of this patent is to improve the aromatization activity, the acidity and pore structure of the molecular sieve are not modified, and the selectivity of p-xylene is not involved.

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