Catalytic cracking method and system for producing propylene and high-octane gasoline

Abstract

The invention relates to a catalytic cracking method and system for producing propylene and high-octane gasoline. The method includes the following steps: introducing preheated high-quality heavy oilfrom the lower part of a dilute-phase conveying bed into the dilute-phase conveying bed to be in contact with a first catalytic cracking catalyst, and performing a primary catalytic cracking reactionfrom the bottom to the top to obtain a primary reaction product and a semi-spent catalyst; sending the obtained primary reaction product and the semi-spent catalyst to a dense-phase fluidized bed, andcontinuing a secondary catalytic cracking reaction to obtain a secondary reaction product and a first spent catalyst; and introducing preheated inferior heavy oil from the lower part of a rapid fluidized bed into the rapid fluidized bed to be in contact with a second catalytic cracking catalyst, and performing a tertiary catalytic cracking reaction from the bottom to the top to obtain a tertiaryreaction product and a second spent catalyst. The method and system provided by the invention have a low yield of coke and dry gas, and a high yield of the low-carbon olefin and the high-octane gasoline during catalytic cracking.

Description

technical field [0001] The invention relates to a catalytic cracking method and system for producing propylene and high-octane gasoline. Background technique [0002] Propylene is an important organic chemical raw material. In 2016, the equivalent consumption of propylene in my country was 33.8 million tons, and the equivalent self-sufficiency rate was 75.2%. It is estimated that by 2020, the equivalent consumption of propylene in my country will reach 39 million tons, and there is still a certain space for its production capacity gap. At present, 61% of the world's propylene comes from the by-products of steam cracking to produce ethylene, and 34% comes from the by-products of gasoline and diesel produced by catalytic cracking units in refineries. Among them, steam cracking uses naphtha and other light oils as raw materials to produce ethylene through thermal cracking And propylene, with the lightening of steam cracking raw materials, the amount of propylene produced by st...

AI Technical Summary

Problems solved by technology

Due to the wide distillation range of heavy oil, large hydrocarbon molecules, complex product structure, and low propylene yield of inferior heavy oil, in order to increase the propylene yield, a higher reaction temperature is adopted, resulting in the increase of propylene yield. Significant increase in dry gas and coke yields

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