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CN-119931698-B - Isotropic coke and preparation method thereof

CN119931698BCN 119931698 BCN119931698 BCN 119931698BCN-119931698-B

Abstract

The invention relates to the technical field of isotropic coke, in particular to isotropic coke and a preparation method thereof. The method comprises the steps of (1) carrying out solid removal treatment on catalytic cracking slurry oil to obtain solid removed oil, (2) contacting the solid removed oil, hydrogen and a hydrogenation catalyst to carry out hydrogenation reaction to obtain hydrogen-rich gas and hydrogenation oil, (3) distilling the hydrogenation oil to obtain distillate oil with the boiling point of 355-520 ℃, and (4) carrying out delayed coking on the distillate oil and optional auxiliary oil to obtain isotropic petroleum coke. According to the preparation method of the isotropic coke, the isotropic coke prepared by taking the catalytic cracking slurry oil as the raw material can be used for producing the lithium ion battery cathode carbon material, so that the outlet of the catalytic cracking slurry oil is solved, the added value of the catalytic cracking slurry oil is obviously improved, and the preparation method is suitable for industrial popularization.

Inventors

  • FAN QIMING
  • SHEN HAIPING
  • LI QI
  • LIU ZIBIN
  • YAN LONG

Assignees

  • 中国石油化工股份有限公司
  • 中石化石油化工科学研究院有限公司

Dates

Publication Date
20260505
Application Date
20240131
Priority Date
20231101

Claims (20)

  1. 1. A method for producing isotropic coke, the method comprising the steps of: (1) Performing solid removal treatment on the catalytic cracking slurry oil to obtain solid removal oil; (2) Contacting the de-solidified oil, hydrogen and a hydrogenation catalyst to carry out hydrogenation reaction to obtain hydrogen-rich gas and hydrogenated oil; The hydrogenation catalyst comprises a hydrogenation protective agent and a hydrogenation refining agent; The hydrogenation reaction is carried out in a fixed bed reactor, wherein a hydrogenation protecting agent and a hydrogenation refining agent are sequentially filled in the fixed bed reactor, and the filling volume ratio of the hydrogenation protecting agent to the hydrogenation refining agent is 5-25:75-95; (3) Distilling the hydrogenated oil to obtain distillate oil with the boiling point of 300-550 ℃; (4) Carrying out delayed coking on the distillate oil and the auxiliary oil to obtain isotropic coke; The auxiliary oil is one or more selected from atmospheric residuum, vacuum residuum, thermal cracking residuum and furfural extract oil; The S content in the isotropic coke is less than or equal to 0.55wt%, the ash content is less than or equal to 0.3wt%, the volatile component is less than or equal to 8wt%, the true density is more than or equal to 2.0g/cm 3 , the tap density of the isotropic coke with the average particle size of 0.5-1mm is more than or equal to 0.85g/cm 3 , the particle uniformity is more than or equal to 0.7, and the particle uniformity is tested by adopting a thermal expansion coefficient ratio method.
  2. 2. The production method according to claim 1, wherein the catalytic cracking slurry oil comprises 10 to 20wt% of saturated hydrocarbons, 55 to 75wt% of aromatic hydrocarbons, 10 to 25wt% of gum and 1 to 8wt% of asphaltenes, based on the total mass of the catalytic cracking slurry oil.
  3. 3. The production process according to claim 1, wherein the catalytic cracking slurry oil has an ash content of 0.005 to 0.4wt%, a sulfur element content of 0.3 to 1.5wt%, a nitrogen element content of 0.1 to 0.5wt%, and a total metal element content of 200 to 600 μg/g.
  4. 4. The process according to claim 1, wherein the means of de-solidification is selected from sedimentation and/or filtration.
  5. 5. The process according to claim 4, wherein the sedimentation comprises separating an upper clarified liquid after allowing the catalytic cracking slurry oil to stand at 100 to 120 ℃ for 36 to 60 hours.
  6. 6. The method of claim 4, wherein the filtering comprises filtering the catalytic cracking slurry oil at 160-200 ℃.
  7. 7. The process according to claim 1, wherein the hydrogenation protecting agent is selected from RG-20B and/or RG-30B.
  8. 8. The method of claim 7, wherein the hydro-protecting agent is RG-30B.
  9. 9. The method of claim 1, wherein the hydrofinishing agent is RMS-30.
  10. 10. The process of claim 1, wherein the loading volume ratio of the hydroprotectant to the hydrofinishing agent is 10-15:85-90.
  11. 11. The process according to claim 1, wherein the hydrogenation reaction is operated at a temperature of 280-445 ℃, a hydrogen partial pressure of 2-10MPa, a volume space velocity of 0.2-2h -1 , and a hydrogen-oil volume ratio of 200-1000 Nm 3 /m 3 .
  12. 12. The production process according to claim 11, wherein the hydrogenation reaction is operated under conditions of a hydrogenation reaction temperature of 300 to 350 ℃, a hydrogen partial pressure of 3 to 6MPa, a volume space velocity of 0.6 to 1.2 h -1 , and a hydrogen-oil volume ratio of 600 to 800Nm 3 /m 3 .
  13. 13. The process according to any one of claims 1 to 12, wherein after the hydrogenation reaction, the hydrogenation product is subjected to gas-liquid separation to obtain a hydrogen-rich gas and a hydrogenated oil, wherein the gas-liquid separation is carried out at a separation temperature of 200 to 250 ℃ and a separation pressure of 3 to 5MPa.
  14. 14. The production process according to claim 13, wherein the hydrogen-rich gas is added to the hydrogen gas and returned to the hydrogenation reaction for recycling.
  15. 15. The production method according to any one of claims 1 to 12, wherein the distillation is performed in a reduced pressure distillation column.
  16. 16. The production process according to any one of claims 1 to 12, wherein the hydrogenated oil is distilled to obtain a distillate with a boiling point of 330 to 510 ℃.
  17. 17. The production process according to claim 1, wherein the auxiliary oil is a vacuum residue.
  18. 18. The preparation method according to any one of claims 1 to 12, wherein the distillate and the auxiliary oil are subjected to delayed coking treatment, wherein the mass ratio of the distillate to the auxiliary oil is 5 to 15:1.
  19. 19. The preparation method according to claim 18, wherein the mass ratio of the distillate oil to the auxiliary oil is 8-12:1.
  20. 20. The production process according to any one of claims 1 to 12, wherein the operating conditions of the delayed coking process include a furnace outlet temperature of 440 to 550 ℃, a coke drum top temperature of 400 to 460 ℃, a coke drum top pressure of 0.3 to 1MPa, and a recycle ratio of 0.4 to 1.5.

Description

Isotropic coke and preparation method thereof Technical Field The invention relates to the technical field of isotropic coke, in particular to isotropic coke and a preparation method thereof. Background The lithium ion battery has the advantages of high voltage, high energy, long cycle life, no memory effect and the like, and has been widely applied in the fields of consumer electronics, electric tools, medical electronics and the like. It is expected that the demand for lithium ion battery anode materials will also increase. Lithium ion batteries generally include a battery case, a positive electrode, a negative electrode, a separator, and an electrolyte. Wherein the negative electrode is prepared from a negative electrode material. The lithium ion battery anode material mainly comprises a metal lithium anode material, a carbon-based anode material, a silicon-based anode material, a tin-based anode material, a germanium-based anode material, a lithium titanate anode material and the like. The carbon-based negative electrode material has the advantages of small volume expansion after lithium intercalation, low oxidation-reduction potential, high coulomb efficiency and long cycle life, and the commercialized lithium ion battery negative electrode material is mainly a carbon-based negative electrode material at present. The isotropic focus means that the physical properties and chemical properties of the focal length do not change along with the spatial direction, i.e. the indexes of thermal properties, mechanical properties, electrical properties such as thermal expansion coefficient, specific resistance, etc. in all directions are approximately equivalent. The optical structures in all directions on the microcosmic scale are fine mosaic structures, and have no single orientation. Compared with the common carbon material, the isotropic coke has the characteristics of high isotropy, high strength, high density, low porosity and the like, and can be used for producing the lithium battery cathode material. For example, CN113422026a discloses a negative electrode material that can be charged at low temperature prepared by using isotropic coke and a preparation method thereof. CN106356530a discloses a negative electrode material which is prepared from granular or spheroidic isotropic coke as raw material through graphitization treatment and can be used for lithium ion batteries. CN110734779A discloses an isotropic coke suitable for a lithium battery cathode raw material and a preparation method thereof, low-temperature coal tar is used as a raw material, the low-temperature coal tar is centrifuged by a super centrifuge, the centrifuged low-temperature coal tar is sent into a flash evaporator for flash evaporation to obtain a flash evaporation material, and then the flash evaporation material is subjected to coking treatment under inert atmosphere to obtain the isotropic coke for the lithium battery cathode raw material. CN114525153a discloses a method for preparing isotropic coke for lithium ion electrode negative electrode material, which comprises vacuum flash evaporating aromatic oil to remove quinoline insoluble substances to obtain flash evaporation oil, mixing flash evaporation oil with nucleating agent in proportion, carrying out polymerization reaction, and coking the polymerization oil to prepare isotropic coke. At present, catalytic cracking slurry oil, in particular to high-sulfur high-ash catalytic cracking slurry oil, is generally delivered as low-cost fuel oil, and if the catalytic cracking slurry oil can be used for preparing isotropic coke which can be used for producing lithium ion battery cathode carbon materials, the added value of the catalytic cracking slurry oil can be obviously improved, and good economic benefit is brought. None of the methods disclosed in the above patents are suitable for processing catalytically cracked slurry oils. Accordingly, it is desirable to provide a method for preparing isotropic coke useful for producing lithium ion battery negative electrode carbon materials using high sulfur and high ash catalytic cracking slurry oil. Disclosure of Invention The invention aims to solve the problem that in the prior art, high-sulfur high-ash catalytic cracking slurry oil is difficult to directly utilize to prepare isotropic coke which can be used for producing a lithium ion battery negative electrode carbon material, and provides isotropic coke and a preparation method thereof. The first aspect of the invention provides a method for preparing isotropic petroleum coke, wherein the method comprises the following steps: (1) Performing solid removal treatment on the catalytic cracking slurry oil to obtain solid removal oil; (2) Contacting the de-solidified oil, hydrogen and a hydrogenation catalyst to carry out hydrogenation reaction to obtain hydrogen-rich gas and hydrogenated oil; (3) Distilling the hydrogenated oil to obtain distillate oil with the boiling point of 300-550 ℃; (