Device for catalytically cracking heavy oil in sections and application thereof

Abstract

The invention relates to a device for catalytically cracking heavy oil in sections and application thereof. A riser reactor and a combined reactor are arranged beside a regenerator, and bottoms of the riser reactor and the combined reactor are connected with the bottom of the regenerator through a catalyst delivery pipe and a regenerated catalyst slide valve; the upper parts of the riser reactor and the combined reactor are respectively connected with an oil-gas separator; the combined reactor consists of a fast bed and a transport bed; the fast bed is arranged below the transport bed and the height of the fast bed is 1 to 50 percent of height of the combined reactor; a rapid cooling agent inlet is formed on the upper part of the fast bed; the oil-gas separator and a top cyclone are arranged in a precipitator above the regenerator; the precipitator is communicated with the regenerator through a stripping section and the catalyst delivery pipe; and catalytic stocks with different properties enter the two independent reactors with different structures, and are reacted according to respectively optimized process conditions, so that inferior stocks and high-quality stocks are prevented from performing vicious adsorption competition and blocking the reaction, and the yield of light oil and liquid is improved.

Description

technical field [0001] The invention relates to a heavy oil zone catalytic cracking device and application for improving heavy oil catalytic cracking reaction efficiency. Background technique [0002] For the heavy oil catalytic cracking process, the chemical composition of the feedstock is the decisive factor for its reactivity. However, the chemical composition of heavy oil catalytic cracking raw materials varies with the range of its process. A fraction containing a large number of components that are easy to handle in catalytic cracking units has different distillation ranges for different origins and bases, but most of them exist in In fractions less than 520-620°C. This part of the fraction has high hydrogen content and contains a large amount of saturated fen and aromatic fen, which are components that are easily converted under catalytic cracking reaction conditions. Therefore, this part of the fraction can be called a high-quality catalytic raw material. The other...

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Problems solved by technology

However, the current heavy oil catalytic cracking technology does not distinguish the fraction composition of the feed and its reactivity, all of which are mixed together into the catalytic cracking unit and converted in the same reactor and under the same process conditions , did not take optimization measures according to the difference in reaction performance between high-quality and low-quality catalytic raw materials, which caused a mismatch between the properties of the raw material and the reaction environment, and affected the conversion efficiency of the heavy oil catalytic cracking reaction process

[0003] For the heavy oil catalytic cracking reaction, there are great differences in the adsorption and cracking capabilities of various hydrocarbons and non-hydrocarbons in the feedstock on the surface of the catalyst. Strong capacity but low reaction rate, while single-ring aromatics with long side chains and macromolecular isoparaffins and naphthenes have weak adsorption capacity and high reaction rate, which results in competitive adsorption and reaction between different hydrocarbons blocking effect of

Once the condensed-ring non-hydrocarbon compounds and condensed-ring aromatics with strong adsorption capacity and low reaction rate occupy the surface of the catalyst first, their reaction rate is slow, it is not easy to desorb, and even condenses into coke to cover the catalyst surface, causing catalyst deactivation, which is serious. Affects the reaction efficiency of other easily cracked hydrocarbons

As for the high-quality raw material of the heavy oil catalytic cracking unit, which contains a large amount of components that are easy to convert under the catalytic cracking reaction conditions, if this part of the raw material is fed together with the inferior raw material containing a large amount of non-hydrocarbon compounds and polycyclic aromatic hydrocarbons, it is bound to be Vicious adsorption competition and retardation of the reaction occur in the same reaction zone, and the result will affect the reaction conversion of the entire raw material

[0004] On the other hand, a large amount of condensed-ring non-hydrocarbon compounds, condensed-ring aromatics and colloidal asphaltenes in inferior raw materials have a low reaction rate and require a long reaction time to achieve the desired conversion depth

The reaction time of the conventional riser reactor is controlled at about 3s, which is suitable for high-quality raw materials that are easy to convert, but is far from enough for low-quality raw materials, resulting in a large number of non-productive materials. The completely converted heavy components are adsorbed on the spent agent and brought into the stripping section. Some of these heavy components are stripped out and enter the settler, which is easy to condense, causing coking in the settler, and the other part is brought into the regenerator like coke. Burned off ("Some re-understandings on the reaction process of heavy oil catalytic cracking - the proposal of a new multi-zone coordinated heavy oil catalytic cracking technology MZCC". Gao Jinsen, Xu Chunming, Lu Chunxi, Mao Yu, Oil Refining Technology and Engineering, 2006, 36 (12): 1-6;), also seriously reduces the light oil yield and liquid yield of heavy oil catalytic cracking process

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