Multifunctional residual oil catalytic cracking method and device

Abstract

The invention discloses a multifunctional residual oil catalytic cracking method and belongs to the technical field of petrochemical engineering and resource utilization. The method comprises the steps of regenerant and residual oil feeding, residual oil and regenerant mixing, vaporization, cracking and conversion. The method is characterized in that a high-activity low-temperature catalyst is introduced to the middle of a main reactor to achieve catalyst activity improvement and temperature reduction of the rear portion, and then hydrogen transfer, isomerization and aromatization of the rear portion are promoted; furthermore, the catalyst to oil ratio of the front portion and the temperature of the feeding stage are increased, so that initial cracking and vaporization of residual oil are promoted and high-temperature short-contact time cracking is achieved; an auxiliary reactor is arranged to guide a regenerant from a regenerator to be lifted by gasoline, so that cracking conversion reaction is conducted, and a high-activity spent catalyst which is 300-550 DEG C is conveyed to the middle of the main reactor. The invention further provides a residual oil catalytic cracking device comprising the main reactor and the auxiliary reactor for realizing the method. By the adoption of the method and device, residual oil conversion capacity can be improved remarkably, gasoline quality can be improved, and the yield of propylene, gasoline and light aromatics is high.

Description

technical field [0001] The invention belongs to the technical fields of petrochemical industry and resource utilization, and in particular relates to a multifunctional residual oil catalytic cracking method and device. Background technique [0002] With the increasing development of petroleum resources, the crude oil is getting heavier and heavier, and the feedstock for catalytic cracking is also getting heavier. The catalytic cracking process is a process in which heavy oil undergoes a gas-solid catalytic cracking reaction on a catalyst to generate light oil. The heavy raw oil in the catalytic cracking unit enters the bottom of the riser reactor after being atomized, and firstly undergoes initial cracking and vaporization of the heavy raw oil in contact with the high-temperature regeneration agent, and then the gas-solid catalytic cracking reaction occurs, and the reaction oil gas and the regeneration agent are converted from The outlet of the riser reactor flows out, and ...

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Problems solved by technology

At present, there are generally two problems in the heavy oil catalytic cracking riser reactor: 1. The catalyst-oil ratio is too low to meet the optimization requirements, and the catalytic activity of the catalyst is low during the catalytic reaction process. The catalytic activity of the 1 / 3 length above the heavy oil nozzle is only 1 of the initial activity. / 2, the catalyst activity at 1 / 2 length is less than 1 / 3 of the initial activity, and the 1 / 2 length behind the riser is carried out under low catalyst activity, which seriously deviates from the optimal reaction conditions

2. The temperature at the bottom of the riser reactor is 20-30°C higher than the outlet temperature, and the wax oil raw material can meet the requirements. However, the boiling point of the heavy raw material oil is greatly increased, so that most of the heavy oil cannot be vaporized, and it exists in the form of unvaporized oil. It leads to an increase in the coking rate of the device, and even causes coking in the riser reactor and the settler

Recently, some heavy oil catalytic cracking units have adopted regenerant cooling measures. After the application of this technical measure, the circulation rate of the catalyst increases, the ratio of catalyst to oil and the activity of the catalyst in the reaction process are improved, but the temperature at the bottom of the riser is further reduced when the outlet temperature remains unchanged. Lowering the temperature of the agent and the temperature at the bottom of the riser at the same time is not good for the initial cracking and vaporization of heavy feedstock oil (especially low-quality residual oil), and improper handling when processing low-quality residual oil will lead to an increase in coke formation rate

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