Combined method for separating fluid catalytic cracking slurry oil and preparing oil-series needle coke

Abstract

The invention provides a combined method for separating fluid catalytic cracking slurry oil and preparing oil-series needle coke. C3-C5 light dydrocarbon cut fraction is adopted as extraction solvent for conducting sub-critical or super-critical extraction on fluid catalytic cracking slurry oil, solvent is recovered from an obtained extraction oil phase in a super-critical mode to prepare extraction components, the extraction components serve as raw materials for preparing middle phase asphalt, and the middle phase asphalt is prepared through retrogressive reaction and then subjected to delayed coking reaction to prepare high-quality oil-series needle coke. When the sulfur content of fluid catalytic cracking slurry oil is high, extraction light components can be subjected to hydrodesulfurization treatment first, hydrogenated oil is subjected to fractionation to collect hydrogenation tail oil, the hydrogenation tail oil serves as a raw material for preparing middle phase asphalt, and then the needle coke is prepared. By means of the method, by controlling the preparation of middle phase asphalt and the coking procedure of the needle coke to be independent of each other, industrial implementation is easier, and fluid catalytic cracking slurry oil can be sufficiently used and the high-quality needle coke material can be prepared.

Description

technical field [0001] The invention relates to a combined method for separating catalytic cracking oil slurry and preparing oil-based needle coke, specifically comprising a combined process for separating catalytic cracking oil slurry and delayed coking to produce oil-based needle coke. Background technique [0002] Needle coke is a carbon material mainly used in the production of high-power and ultra-high-power graphite electrodes. According to different sources of raw materials, needle coke is divided into two types: oil-based and coal-based. Among them, oil-based needle coke is processed from heavy oil in refineries and is more widely used. Its market demand is large, but production The ability is insufficient. In the prior art, the production of oil-based needle coke generally adopts the delayed coking process, which includes three parts: raw material oil pretreatment, delayed coking coking and calcination. Due to technical difficulties, higher requirements for proces...

AI Technical Summary

Problems solved by technology

For solid impurities in oil slurry, filtration and other methods can only separate larger particles, but it is difficult to separate smaller solid particles, such as catalyst powder, let alone remove asphaltenes and other components.

Vacuum distillation and solvent extraction are commonly used heavy oil separation methods, but the removal rate of vacuum distillation is limited. If you want to increase the removal rate of distillation, you must increase the distillation temperature, because the oil slurry has a high content of condensed ring aromatics and asphaltenes and other impurities, high-temperature distillation can easily cause coking in the heating furnace and distillation tower, which not only makes it difficult to increase the extraction rate of the extract, but also shortens the life of the equipment

As for the use of solvent extraction technology, there are researches and consensus operations. It is the goal to try to separate the aromatic components from the oil slurry. Therefore, according to the properties of the catalytic cracking oil slurry, furfural and other solvents that can extract aromatics are used. Extraction and separation is currently the technical direction of research and attention, but the problem faced in industrial production is that for systems such as oil slurry, although furfural solvents can extract aromatics, colloidal asphaltenes are also extracted at the same time. Not only is it difficult to achieve the phase separation of extracts and non-aromatics, but it is also difficult to achieve the purpose of refining the slurry raw material. Therefore, it is necessary to perform deasphaltene and solid impurities pretreatment on the slurry to apply this technology

On the other hand, the properties of crude oil and the catalytic cracking process also lead to differences in the properties of oil slurry, especially for oil slurry with high sulfur aromatic components, directly used as raw materials will seriously affect the quality of mesophase pitch and needle coke, but the oil slurry For direct hydroprocessing, the impurities in the oil slurry will quickly lead to catalyst bed blockage and catalyst failure, which is even more undesirable in industrial production. It is itself a difficult problem for the production of mesophase pitch. The process of producing high-quality needle coke poses technical challenges

[0006] In addition, the current process of preparing needle coke basically uses delayed coking equipment. The coking equipment must not only complete the synthesis of mesophase pitch, but also complete the coking reaction to prepare needle coke. Therefore, the process conditions need to be changed in each cycle. The temperature and pressure changes are relatively large, which makes it difficult to control the coking process and ensure the quality of needle coke

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