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CN-121975541-A - Co-production process method for spinnable mesophase pitch and petroleum coke

CN121975541ACN 121975541 ACN121975541 ACN 121975541ACN-121975541-A

Abstract

The invention discloses a co-production process method of spinnable mesophase pitch and petroleum coke. The method comprises the steps of (1) carrying out hydrofining and fractionation on catalytic slurry oil to obtain refined slurry oil and hydrogenated tail oil, (2) carrying out extraction and separation on part of the refined slurry oil obtained in the step (1) to obtain an extraction component, (3) carrying out reduced pressure distillation on the extraction component obtained in the step (2) to obtain an extraction distillate oil, (4) carrying out a co-carbonization reaction on the extraction distillate oil obtained in the step (3) and part of the refined slurry oil obtained in the step (1) under the action of inert atmosphere and a co-carbonization agent to obtain spinnable mesophase pitch, and (5) carrying out delayed coking reaction on the hydrogenated tail oil obtained in the step (1) and part of the refined slurry oil obtained in the step (1) to obtain petroleum coke. The method improves the wide area mesophase content of the spinnable mesophase pitch product, and can co-produce petroleum coke with high added value.

Inventors

  • ZHANG XINYUE
  • CHU RENQING
  • GUO DAN
  • WU YUN
  • ZHANG YUANYUAN

Assignees

  • 中国石油化工股份有限公司
  • 中石化（大连）石油化工研究院有限公司

Dates

Publication Date
20260505
Application Date
20241030

Claims (10)

  1. 1. A process method for co-producing spinnable mesophase pitch and petroleum coke comprises the following steps: (1) Hydrofining and fractionating the catalytic slurry oil to obtain refined slurry oil and hydrogenated tail oil; (2) Extracting and separating part of refined oil slurry obtained in the step (1) to obtain an extraction component; (3) Distilling the extracted component obtained in the step (2) under reduced pressure to obtain extracted distillate; (4) Carrying out a co-carbonization reaction on the extracted distillate oil obtained in the step (3) and the partially refined slurry oil obtained in the step (1) under the action of inert atmosphere and a co-carbonization agent to obtain spinnable mesophase pitch; (5) And (3) carrying out delayed coking reaction on the hydrogenated tail oil obtained in the step (1) and the partially refined slurry oil obtained in the step (1) to obtain petroleum coke.
  2. 2. The method according to claim 1, wherein in step (1), the catalytic slurry is characterized by a 5% distillation temperature of 250-450 ℃, preferably 350-400 ℃, a 95% distillation temperature of 480-600 ℃, preferably 510-570 ℃, an aromatic carbon content of 30-90%, preferably 50-80%, ash content < 0.07%, preferably <0.06%, and a sulfur content of 0.85-1.28%.
  3. 3. The method according to claim 1, wherein in the step (1), the reaction condition of the hydrofining reaction zone is that the reaction temperature is 250-450 ℃, preferably 280-350 ℃, the hydrogen partial pressure is 1-10 MPa, preferably 2-5 MPa, the hydrogen-oil volume ratio is 500-1200, preferably 500-1000, and the liquid hourly space velocity is 0.1h -1 ～1.5h -1 , preferably 0.6h -1 ～1.2h -1 ; And/or in the step (1), the temperature of a 95% distillation point of the refined oil slurry is 480-500 ℃, the sulfur content is 0.40-0.75wt%, the temperature of a 5% distillation point of the hydrogenated tail oil is 490-520 ℃, the sulfur content is 0.65-1.25wt%, and the mass content of quinoline insoluble matters is 3.0-5.0wt%.
  4. 4. The process according to claim 1, wherein in step (2) the extraction solvent is at least one of C4-C6 alkanes, preferably isobutane; And/or in step (2), the mass ratio of the refined slurry oil to the extraction solvent is 1:1.5-5.5, preferably 1:2.5-5.0; and/or in the step (2), the extraction condition is that the temperature of the top of the tower is 110-180 ℃, preferably 120-170 ℃, the temperature of the bottom of the tower is 80-160 ℃, preferably 100-150 ℃, and the extraction pressure is 3.0-10.0 MPa, preferably 4.0-7.0 MPa.
  5. 5. The process according to claim 1, wherein in step (3) the vacuum fractionation is carried out to obtain an extracted distillate, the extracted distillate has a 5% distillation point temperature of 370 ℃ to 395 ℃ and a 95% distillation point temperature of 430 ℃ to 450 ℃ and an ash content of <0.035wt%, preferably in step (3), the aromatic hydrocarbons with four and more rings account for 45wt% to 60wt% in the hydrocarbon composition distribution of the extracted distillate.
  6. 6. The method according to claim 1, wherein in the step (4), the mass ratio of the refined slurry oil to the extracted distillate is 1:3-5, preferably 1:3-3.5.
  7. 7. The method according to claim 1, wherein in the step (4), the co-carbonizing agent is at least one of tetrahydronaphthalene, decalin or tetrahydroquinoline, preferably tetrahydronaphthalene, and the mass of the co-carbonizing agent added accounts for 5-25 wt%, preferably 5-15 wt% of the total mass of refined oil slurry and extracted oil.
  8. 8. The method according to claim 1, wherein in the step (4), the reaction conditions of the co-carbonization reaction are that the reaction temperature is 370-455 ℃, preferably 405-450 ℃, the reaction pressure is 1.0-6.0 mpa, preferably 2.5-4.0 mpa, and the reaction time is 4-10 hours, preferably 4-8 hours; Preferably, after the co-carbonization reaction, the mixture is adjusted to normal pressure, and then nitrogen bubbling and purging are carried out under the condition of air inflow of 3L/(min.kg) to 9L/(min.kg), preferably 4L/(min.kg) to 9L/(min.kg) at the temperature of 350 ℃ to 430 ℃, preferably 360 ℃ to 400 ℃, the purging time is 3h to 6h, preferably 4h to 6h, and the mixture is cooled to the room temperature of 10 ℃ to 30 ℃, so that the spinnable mesophase pitch is obtained.
  9. 9. The method according to claim 1, wherein in the step (4), the softening point of the mesophase pitch is 277-296 ℃, the carbon residue value is 78-86 wt%, the toluene insoluble matter is 5.2-18.8 wt%, the quinoline insoluble matter is less than 0.025wt%, the coking value is 62.4-87.4 wt%, and the mesophase mass content is 96-99 wt%; Preferably, the flow field type mesophase texture of the mesophase pitch is not less than 89.93% by volume; Preferably, the mesophase pitch single-hole melt spinning is performed, and the continuous spinning is performed at 200-350 m/min and higher than 10000m.
  10. 10. The method according to claim 1, wherein in step (5), the mass ratio of the hydrogenated tail oil to the refined slurry oil is 1:2-5, preferably 1:2-4; And/or in the step (5), the reaction condition of the delayed coking is that the outlet temperature of a heating furnace is 485-530 ℃, preferably 490-520 ℃, the top pressure of a coke tower is 0.2-2.0 MPa, preferably 0.4-1.0 MPa, the circulation ratio is 0.2-0.5, preferably 0.2-0.3 by mass, the coking cycle of the pressure swing operation is 20-60 h, preferably 30-60 h, and the pressure change rate is 0.1-15.0 MPa/h, preferably 0.3-6.0 MPa/h; And/or, in the step (5), the obtained petroleum coke is low-sulfur petroleum coke, the sulfur content is lower than 0.7wt%, the ash content is lower than 0.040wt%, the volatile component is lower than 5.0wt%, and the mass content of (silicon+aluminum) is lower than 50 mug/g.

Description

Co-production process method for spinnable mesophase pitch and petroleum coke Technical Field The invention relates to the field of catalytic slurry oil processing and utilization, in particular to a co-production process method of spinnable mesophase pitch and petroleum coke. Background The catalytic cracking slurry oil is a main byproduct of a catalytic cracking process of a heavy oil product, contains a large amount of solid impurities (usually 0.3% -0.8%), colloid, asphaltene, catalyst powder (usually about 0.05%) and other components which need to be removed, and simultaneously contains more than 50% of aromatic hydrocarbon components, so that the catalytic cracking slurry oil is an important potential chemical product raw material, and particularly can be used for producing carbon materials, such as needle coke, mesophase pitch, carbon black, petroleum coke and other products. How to reasonably and efficiently utilize the catalytic cracking slurry oil is a continuous concern in the industry and the academy in recent years. CN108795466a discloses a method for preparing mesophase pitch by FCC clear oil induced polycondensation. The method takes components with boiling points lower than 530 ℃ in naphthenic FCC clear oil as raw materials, and the components react for 2-10 hours at the temperature of 390-450 ℃ and the pressure of 2MPa to obtain low-softening-point mesophase pitch. However, this method requires the addition of an inducer to promote the formation of mesophase pitch. CN105238430B discloses a method for preparing mesophase pitch by hydroisomerization-thermal polycondensation of catalytic cracking slurry oil. The method prepares the mesophase pitch by hydroisomerization-thermal polycondensation of FCC slurry oil of naphthenic crude oil or intermediate crude oil. But requires the addition of an additional hydrogen donor to obtain high quality mesophase pitch. CN113122333a discloses a method and system for producing low sulfur petroleum coke. The method comprises the steps of enabling catalytic slurry oil to contact with coking reaction effluent in a coking fractionating tower, separating the catalytic slurry oil to obtain gas, light fraction and heavy fraction, carrying out polymerization on the light fraction to obtain polymer, carrying out solid removal treatment on the heavy fraction, mixing purified oil obtained after solid removal treatment with hydrogen, carrying out hydrotreatment to obtain refined oil, mixing the obtained polymer with the refined oil, heating the mixture, and then entering a delayed coking device for reaction to obtain low-sulfur petroleum coke. The method is complex to operate, and the sulfur content of the product petroleum coke is still further reduced. Spinnable mesophase pitch is an important precursor material for producing high-performance pitch-based carbon fibers, and is formed by stacking large-plane polycyclic aromatic hydrocarbon molecules, and catalytic cracking slurry oil rich in aromatic hydrocarbon components is one of the raw material sources for producing spinnable mesophase pitch. The high-quality low-sulfur coke is petroleum coke with sulfur content less than 3%, and can be used for producing graphite electrodes and carburant. In recent years, the price of low sulfur coke is greatly increased, and the price is greatly dependent on import, and the catalytic cracking slurry oil can be used as a raw material of low sulfur petroleum coke after desulfurization and solid removal treatment. There is no related art publication of co-producing spinnable mesophase pitch and low sulfur petroleum coke. Disclosure of Invention Aiming at the defects existing in the prior art, the invention provides a co-production process method of spinnable mesophase pitch and petroleum coke. The method ensures that the catalytic slurry oil raw material is more properly and completely utilized, improves the wide area mesophase content of the spinnable mesophase pitch product, and realizes the simultaneous production of petroleum coke with high added value. The invention provides a co-production process method of spinnable mesophase pitch and petroleum coke. The method comprises the following steps: (1) Hydrofining and fractionating the catalytic slurry oil to obtain refined slurry oil and hydrogenated tail oil; (2) Extracting and separating part of refined oil slurry obtained in the step (1) to obtain an extraction component; (3) Distilling the extracted component obtained in the step (2) under reduced pressure to obtain extracted distillate; (4) Carrying out a co-carbonization reaction on the extracted distillate oil obtained in the step (3) and the partially refined slurry oil obtained in the step (1) under the action of inert atmosphere and a co-carbonization agent to obtain spinnable mesophase pitch; (5) And (3) carrying out delayed coking reaction on the hydrogenated tail oil obtained in the step (1) and the partially refined slurry oil obtained in the step (1) to obtain petr