Catalytic cracking method and device

Abstract

The invention discloses a catalytic cracking method and a device for realizing the method, belonging to the technical field of the petrochemical industry. Catalytic cracking is carried out in a main reactor and an auxiliary light raw material reactor, a regenerated catalyst from a regenerator is subjected to contact reaction with a raw oil in a first reaction zone of the main reactor, and a reaction mixture is upwards fed to a flow divider so as to separate out the catalyst; the separated catalyst directly flows into a stripping section, and reaction oil gas is upwards fed into a second reaction zone of the main reactor along a delivery pipe; a spent catalyst from the auxiliary light raw material reactor is firstly fed into a catalyst replenishing zone and then is upwards fed into the second reaction zone of the main reactor from the catalyst replenishing zone so as to be mixed with the reaction oil gas from the first reaction zone and make the oil gas subjected to continuous reaction; and after the reaction is finished, the oil gas and the catalyst are separated, the oil gas is led out and then fed into a subsequent fractionating system through an oil gas outlet pipeline, the catalyst flows into the stripping section and is stripped and fed into the regenerator for regeneration, together with the catalyst separated out by the flow divider in the first reaction zone.

Description

technical field [0001] The invention relates to the field of petrochemical technology, in particular to a method and device for catalytic cracking of petroleum hydrocarbon raw materials. Background technique [0002] Catalytic cracking unit is the most important gasoline production unit. The vast majority of motor gasoline in the world comes from catalytic cracking unit. Conventional catalytic cracking uses riser reactor. [0003] The biggest disadvantage of the existing riser reactor is that the riser is too long, and the catalyst activity at the outlet of the riser is only about 1 / 3 of the initial activity. Therefore, in the second half of the riser reactor, the catalyst activity and selectivity have sharply increased Decrease, catalytic effect worsens, thermal cracking reaction and other unfavorable secondary reactions increase, which not only limits the improvement of single-pass conversion rate, but also causes the olefin content of catalytic gasoline to be as high as 4...

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Problems solved by technology

However, in this technology, the catalyst separated from the first zone must be stripped before entering the regenerator. At the same time, the regenerated catalyst must be transported by the conveying medium before entering the second stage. The stripping steam and conveying medium will all enter the second stage, which will inevitably affect The reaction to the second stage; if the amount of stripping steam is limited, the stripping effect will be affected, and then the regeneration process will be affected; the height difference from the bottom of the external heat extractor to the entrance of the second reaction stage is tens of meters, and the amount of transport medium is large , need to consume a lot of energy; and this technology requires two settlers, two stripping sections, a substantial increase in investment

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