Method and device for preparing ethylene and propylene through catalytic conversion of crude oil

Abstract

The invention relates to a method for preparing ethylene and propylene through direct catalytic conversion of crude oil. According to the method, the crude oil is desalted and dehydrated and then is divided into a crude oil light component and a crude oil heavy component with a higher boiling point by using a flash tower according to boiling points, and then catalytic conversion is carried out byadopting a fluidization catalysis method, so ethylene and propylene are prepared by catalyzing the crude oil; crude oil catalytic conversion is carried out in a device provided with a first reaction regeneration system and a second reaction regeneration system; and a catalytic cracking reaction of the high-boiling-point macromolecular crude oil heavy component is firstly carried out in the first reaction regeneration system, and then catalytic cracking and thermal cracking are further carried out under the gradual heating condition of the second reaction regeneration system to prepare ethyleneand propylene after a catalyst is replaced. According to the method, different fractions of the crude oil are subjected to selective catalytic conversion by directly using targeted catalysts, so ethylene and propylene are prepared through catalytic conversion of the crude oil; an atmospheric and vacuum system does not need to be arranged, the yields of ethylene and propylene can be increased, andeconomical efficiency is greatly improved. The invention also provides a device for realizing the method.

Description

Technical field [0001] The invention belongs to the technical field of catalytic conversion of crude oil, and particularly relates to a method for preparing ethylene and propylene by catalytic conversion of crude oil. The present invention also provides a device for realizing the above method. Background technique [0002] Low-carbon olefins represented by ethylene and propylene are the most basic raw materials in the chemical industry. The existing catalytic conversion technology produces low-carbon olefins while producing gasoline and diesel, which is far from meeting the current market demand for organic chemical raw materials. Aromatics are important organic chemical raw materials second only to ethylene and propylene in production and scale. Its derivatives are widely used in the production of chemical fibers, plastics, rubber and other chemical products and fine chemicals. With the continuous development of petrochemical and textile industries, the world The demand for aro...

AI Technical Summary

Problems solved by technology

Although in order to increase the production of low-carbon olefins, 5-8% additives can be added to the regenerator to further convert small molecules, but when the additives are added to the FCC catalyst, due to the dilution of the catalyst, the cracking activity of the catalyst will inevitably decrease.

Usually every 5% additive is added, the cracking conversion rate of heavy oil decreases by 1 percentage point, and the reduction of conversion rate of heavy oil is an important factor that seriously affects the technical economy of FCC. , the improvement of the target product is limited

[0011] 2. Since the second reaction system requires more heat of reaction, coke is generally less, and the heat released by the regeneration of coke itself cannot provide the heat required for the reaction. If the original technology is used to establish an independent second reaction system, it will be restricted by heat balance problems

After the process of first cooling down and then heating up, the investment in equipment and energy consumption is increased, which greatly reduces the economical efficiency of the process technology

[0013] 4. Crude oil to ethylene requires a higher reaction temperature, generally higher than 650°C; the reaction process of catalyzing olefins from catalytic cracking feedstock oil, especially heavy feedstock oil, is a process of gradual cracking and gradual reduction of molecular weight; the smaller the molecule, the more Difficult to activate, the higher the reaction temperature required, the higher the temperature will naturally reheat the cracking reaction, which will affect the selectivity of the target product; how to allocate the reaction temperature and the molecular characteristics of petroleum hydrocarbons, balance the catalytic cracking reaction and thermal cracking reaction, and realize the reaction The limit control of the chemical is of great significance; the desired reaction process is to increase the proportion of catalytic reaction as much as possible in the cracking stage of heavy oil and other macromolecules, limit thermal cracking, and gradually increase the temperature and increase the proportion of thermal cracking reactions in the cracking stage of small molecules; The process heat is provided in the reactor inlet area, and the reaction is a gradual cooling process, especially for the reaction of ethylene production. Due to the high reaction temperature required, the initial stage, that is, the heavy oil cracking stage in the lower part of the reactor, has a higher reaction temperature, and the heavy components are directly Thermal cracking reactions are carried out, reducing the effectiveness of catalytic cracking reactions

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