Method for preparing ethylene and propylene through catalytic cracking

Abstract

The invention discloses a method for preparing ethylene and propylene through catalytic cracking, wherein average particle diameter range of catalyst particles is 1-500 nm; and the method comprises the following steps of: uniformly dispersing the catalyst particles into a reactant; and reacting in a reactor to produce low-carbon-number olefin. The reactant is at least one of naphtha, diesel oil and hydrocarbon mixtures containing C4-C8 olefin; and the catalyst is preferably zeolite, more preferably at last one of ZSM-5 series zeolite, mordenite, beta zeolite and Y zeolite or a product obtained by modifying alkali metal oxide or rare earth metal oxide. By using the method, the yield of ethylene and propylene can be increased, the using amount of the catalyst can be reduced, and the cost can be reduced.

Description

Technical field [0001] The invention relates to the field of organic chemical engineering, and more specifically, to a method for preparing ethylene and propylene by catalytic cracking. Background technique [0002] The catalysts used in petrochemical production mainly include two types: heterogeneous catalysts and homogeneous catalysts. Since homogeneous catalysts are difficult to separate from products, people try to load homogeneous catalysts on carriers, that is, heterogeneous catalysis. After years of research and exploration, industrialization has not been achieved so far, and the problem of loss of active components is difficult to solve. Due to the above-mentioned disadvantages of homogeneous catalysts, most industrial catalysts are heterogeneous catalysts. The following problems are common in the use of heterogeneous catalysts: 1. The amount of catalyst is large, the utilization rate is low, and the service cycle is short; 2. It is easy to form carbon and needs frequent...

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Problems solved by technology

The following problems generally exist in the use of heterogeneous catalysts: 1. The amount of catalyst is large, the utilization rate is low, and the service life is short; 2. It is easy to form carbon and requires frequent regeneration; 3. There are still many active components in the deactivated catalyst that have not been used. role, resulting in waste of resources, etc.

[0007] Since the fixed-bed reaction process uses a heterogeneous catalyst, the main disadvantage is that the catalyst is easy to coke, the service life is short, and frequent regeneration is required; the main disadvantage of the fluidized-bed reaction process is that not only the investment is large, but also the product contains nitrogen and oxygen, resulting in a reaction with hydrogen. , methane, ethylene and other light components are difficult to separate

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