Modification treatment method and application of HZSM-5 molecular sieve catalyst

Abstract

The invention discloses an HZSM-5 molecular sieve catalyst. The HZSM-5 molecular sieve catalyst is based on HZSM-5 molecular sieve which is commonly used in low-carbon hydrocarbon aromatization technology, and the HZSM-5 molecular sieve is subjected to a post-treatment by means of alkali / water vapor double-modification method which comprises the following steps that the HZSM-5 molecular sieve catalyst is added to the alkaline solution for a treatment, then a water vapor treatment is carried out to prepare the modification catalyst. Compared with an unmodified catalyst, the modification catalyst has the advantages that after the molecular sieve is treated by alkali, framework silicon is removed, the framework pore structure is enlarged and a portion of mesopores are formed, therefore the ability to hold carbons is improved; after the molecular sieve is treated by water vapor, framework aluminum is removed and the acidity ratio is adjusted and changed, therefore the ability to resist carbon deposition is enhanced. Accordingly, the modification catalyst is capable of enhancing effectively the stability of the catalyst, greatly prolonging the service life of the catalyst and exhibiting a better reaction performance of low-carbon hydrocarbon aromatization while increasing the aromatization activity.

Description

technical field [0001] The invention relates to the field of light hydrocarbon aromatization catalysis, in particular to a modification treatment method of HZSM-5 molecular sieve catalyst and its application in low-carbon hydrocarbon aromatization. Background technique [0002] Aromatics are the most basic raw materials in the organic chemical industry, mainly derived from petroleum and coal tar. Benzene, toluene, and xylene in aromatics are important basic raw materials in petrochemical industry, and their output and scale are second only to ethylene and propylene. The largest use of benzene is to produce styrene, which can be polymerized to obtain polystyrene, followed by the hydrogenation of benzene to cyclohexane, which is used to produce nylon through the preparation route of cyclohexane oxidation-cyclohexanone-caprolactam. The largest amount of xylene is p-xylene, which can be made into terephthalic acid after high temperature oxidation. It is the main raw material fo...

AI Technical Summary

Problems solved by technology

However, due to its strong solid acidity, it is easy to cause the cracking of low-carbon hydrocarbons to form carbon deposits and deactivation in the catalytic reaction, or low-carbon hydrocarbons generate olefins through carbocation reactions or dehydrogenation reactions, and then oligomerize on the acid center to form Macromolecular polymers lead to coking inactivation

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