Composite molecular sieve catalyst for increasing yield of low-carbon olefins through light hydrocarbon cracking and preparation method thereof

Abstract

The preparation method comprises the following main steps: pre-hydrogenating an LTA molecular sieve, mixing the pre-hydrogenated LTA molecular sieve with a commercial hydrogen type ZSM-5 molecular sieve, and uniformly compounding the molecular sieves by virtue of the synergistic effect of mechanical stirring and ultrasonic mixing, so as to obtain the composite molecular sieve catalyst for increasing the yield of low-carbon olefins through catalytic cracking of light hydrocarbons. Therefore, the advantages of specific pore structures of the two molecular sieves are fully exerted. The catalyst prepared by the method is used for the catalytic cracking reaction of light hydrocarbon, efficient cracking of light hydrocarbon is realized by virtue of the catalytic action of the acidic ZSM-5 molecular sieve with a ten-membered ring pore channel structure, and secondary reaction of a cracking product is inhibited by virtue of an eight-membered ring pore channel structure of the LTA molecular sieve, so that the selectivity of low-carbon olefin is improved; the deactivation rate of the coke generation catalyst is effectively reduced, and the service life of the catalyst is prolonged. The method is simple, efficient and excellent in performance, and has good application value in the process of producing ethylene propylene through catalytic cracking of petroleum.

Description

Technical field: [0001] The invention relates to the field of petrochemical technology, in particular to a catalyst for light hydrocarbon catalytic cracking to produce light olefins with high selectivity and a preparation method thereof. Background technique: [0002] Light olefins (ethylene, propylene and butene) are the most basic raw materials for petrochemical production. At present, the main processes for producing low-carbon olefins include: steam cracking process, catalytic cracking and catalytic cracking process, methanol-to-olefins technology, alkane dehydrogenation process and olefin metathesis, etc. Among them, steam cracking is the most widely used low-carbon olefin production process. After years of development, the steam cracking process has become mature, but there are still problems such as high construction costs, small production capacity, high energy consumption of equipment, low yield of trienes, and carbon emissions. Disadvantages such as large quantity...

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Problems solved by technology

Among them, steam cracking is the most widely used low-carbon olefin production process. After years of development, the steam cracking process has become mature, but there are still problems such as high construction costs, small production capacity, high energy consumption of equipment, low yield of trienes, and carbon emissions. Disadvantages such as large quantity

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