Catalytic cracking method and system

Abstract

The invention relates to the field of catalytic cracking reactions, and discloses a catalytic cracking method and a catalytic cracking system. The method comprises: under the action of a pre-lifting medium, the catalytic cracking raw material is subjected to a catalytic cracking reaction in a riser reactor, the gas phase is separated from the reaction product, and the gas phase is injected into an absorption tower for treatment, and the gas phase is injected from the top of the absorption tower Lean gas is collected and at least a portion of said lean gas is recycled as a pre-lift medium. The catalytic cracking system includes a reaction device equipped with a riser reactor and an absorption tower, the gas phase outlet at the top of the reaction device communicates with the gas phase inlet of the absorption tower, and the lean gas outlet at the top of the absorption tower communicates with the lift The pre-lift medium inlet at the bottom of the tube reactor communicates. By adopting the catalytic cracking method and the catalytic cracking system of the present invention, the gas phase load of the reabsorption tower can be reduced, the absorption effect can be effectively improved, and the propylene component carried in the dry gas can be reduced.

Description

technical field

[0001] The invention relates to the field of catalytic cracking reactions, in particular to a catalytic cracking method and a catalytic cracking system. Background technique

[0002] The pre-lifting technology at the bottom of the catalytic cracking riser is a process technology commonly used in various catalytic cracking units at present. By setting a pre-lifting section at the bottom of the riser, this technology can prevent the catalyst from back-mixing and depositing at the bottom of the riser and promote the catalyst to flow in the feed nozzle. Uniform distribution and good oil contact. The pre-lift medium currently used is generally steam and dry gas. When steam is used as a lifting medium, it will cause the thermal collapse of the catalyst, generate fine powder, and increase the consumption of the catalyst. The latent heat of vaporization of water is large, and the increase in the amount of water vapor will increase the cooling load of the top cooler...

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