Method and device for preparing olefin through catalytic conversion of petroleum hydrocarbon raw material

Abstract

The invention relates to a method for preparing olefin through catalytic conversion of a petroleum hydrocarbon raw material, and belongs to the technical field of petroleum hydrocarbon catalytic conversion. According to the method, heavy petroleum hydrocarbon and hydrocracking tail oil are adopted as raw materials to produce olefin, the heavy petroleum hydrocarbon and the hydrocracking tail oil are subjected to catalytic conversion in a first catalyst environment of a first reactor and a first catalyst environment of a third reactor of a first reaction regeneration system respectively, part orall of a generated gas-phase product enters a second reaction regeneration system, and a secondary high-temperature reaction and a high-temperature reaction are performed in a second catalyst environment to prepare olefin. According to the invention, three gradually increased temperature gradients in series connection, i.e., a first reactor and third reactor low-temperature zone, a second reactorsecondary high-temperature zone and a second reactor high-temperature zone, are arranged, meanwhile, proper special catalysts are respectively prepared for low-temperature cracking and high-temperature cracking, so that double reaction systems and double catalyst circulation are realized, and the yield of a high-value target product is increased.

Description

technical field [0001] The invention belongs to the technical field of catalytic conversion of petroleum hydrocarbons, and in particular relates to a method for producing olefins by catalytic conversion of petroleum hydrocarbon raw materials. The 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 is to produce low-carbon olefins while producing gasoline and diesel, which is far from meeting the current market demand for organic chemical raw materials. Aromatics is an important organic chemical raw material second only to ethylene and propylene in output 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 wo...

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. The production of olefins from petroleum hydrocarbons 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 it is to activate, the higher the reaction temperature is required, and the high 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 The limit control of reaction is significant; 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 heat of the reaction process is provided in the inlet area of ​​the reactor, and the reaction is a process of gradually cooling down, 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 heavy components The thermal cracking reaction is carried out directly, reducing the effect of the catalytic cracking reaction

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