A combined method for separating catalytic cracking oil slurry and preparing oil-based needle coke

Abstract

The invention provides a combined method for separating catalytic cracking oil slurry and preparing oil-based needle coke. Use C3-C5 light hydrocarbon fraction as extraction solvent to carry out subcritical or supercritical extraction of catalytic cracking oil slurry, and the obtained extracted oil phase is recovered by supercritical solvent to make extraction components, and the extraction components are used as the preparation of mesophase pitch Raw materials, the mesophase pitch is prepared by thermal polycondensation reaction, and then the mesophase pitch is prepared by delayed coking reaction to obtain high-quality oil-based needle coke. When the sulfur content of the catalytic cracking oil slurry is high, the extracted light components can be hydrodesulfurized first, and the hydrogenated oil can be fractionated to obtain the hydrogenated tail oil, and the hydrogenated tail oil can be used as the raw material for the preparation of mesophase pitch, and then prepared needle coke. The method of the invention is independent of the preparation of the mesophase pitch and the coking process of the needle coke, which is more conducive to the realization of industrialization, and can make full use of catalytic cracking oil slurry and prepare high-quality needle coke materials.

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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