Search

CN-117778042-B - Combined production process and production system for co-producing needle coke and low-sulfur petroleum coke

CN117778042BCN 117778042 BCN117778042 BCN 117778042BCN-117778042-B

Abstract

The invention discloses a combined production process and a production system for co-producing needle coke and low-sulfur petroleum coke, wherein the combined production process comprises the following steps of mixing catalytic slurry oil and ethylene tar for hydrogenation reaction, and separating hydrogenation reaction products to obtain gas, naphtha, hydrogenated wax oil and hydrogenated tail oil; the hydrogenation wax oil enters a cracking treatment unit to carry out cracking reaction, a cracking reaction product is separated to obtain light oil, middle distillate oil and residual oil, the middle distillate oil is used as needle coke raw material to enter a needle coke production unit to produce needle coke, and the residual oil and hydrogenation tail oil are mixed to enter a low-sulfur petroleum coke production unit to produce low-sulfur petroleum coke. The invention also provides a combined production system for co-producing the needle coke and the low-sulfur petroleum coke. Can effectively solve the problem of excessive hydrogen supply of hydrogenated slurry oil in the needle coke production process and the problem of short startup period of a delayed coking device caused by poor thermal stability of ethylene tar.

Inventors

  • GUO DAN
  • CHU RENQING
  • WU YUN
  • LIANG XITONG
  • GOU LIANZHONG

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
20220920

Claims (20)

  1. 1. A combined production process for co-producing needle coke and low-sulfur petroleum coke, which comprises the following steps: (1) Mixing catalytic slurry oil and ethylene tar, entering a hydrotreating unit, carrying out hydrogenation reaction under the action of hydrogen and a hydrogenation catalyst, and separating hydrogenation reaction products to obtain gas, naphtha, hydrogenated wax oil and hydrogenated tail oil; (2) The hydrogenated wax oil obtained in the step (1) enters a cracking treatment unit for cracking reaction under the action of carrier gas, and light oil, middle distillate and residual oil are obtained after separation of cracked reaction products, wherein the reaction conditions of the cracking treatment unit are that the reaction temperature is 380-520 ℃, the reaction pressure is 0.1-5 MPa, the residence time is 0.01-30 h, and the distillation range of the middle distillate is 320-500 ℃; (3) The middle distillate oil obtained in the step (2) is taken as needle coke raw material to enter a needle coke production unit, and needle coke is obtained after reaction; (4) And (3) mixing the hydrogenated tail oil obtained in the step (1) and the residual oil obtained in the step (2) to enter a low-sulfur petroleum coke production unit, and reacting to obtain the low-sulfur petroleum coke.
  2. 2. The combined production process for co-producing needle coke and low sulfur petroleum coke according to claim 1, wherein the ash content of the catalytic slurry in the step (1) is not more than 0.01wt%.
  3. 3. The combined production process for co-producing needle coke and low sulfur petroleum coke according to claim 1, wherein the ash content of the catalytic slurry in the step (1) is not more than 0.005wt%.
  4. 4. The combined production process for co-producing needle coke and low-sulfur petroleum coke according to claim 1, wherein the mass ratio of the catalytic slurry oil to the ethylene tar in the step (1) is 1:2-1:0.1.
  5. 5. The combined production process for co-producing needle coke and low-sulfur petroleum coke according to claim 1, wherein the mass ratio of catalytic slurry oil to ethylene tar in the step (1) is 1:0.7-1:0.2.
  6. 6. The combined production process for co-producing needle coke and low-sulfur petroleum coke according to claim 1, wherein the reaction condition of the hydrogenation treatment unit in the step (1) is that the reaction temperature is 310-450 ℃, the reaction pressure is 2-20 MPa, the hydrogen-oil volume ratio is 100-2500, and the liquid hourly space velocity is 0.1h -1 ～2.0h -1 .
  7. 7. The combined production process for co-producing needle coke and low-sulfur petroleum coke according to claim 1, wherein the reaction condition of the hydrogenation treatment unit in the step (1) is that the reaction temperature is 340-390 ℃, the reaction pressure is 4-8 MPa, the hydrogen-oil volume ratio is 800-1800, and the liquid hourly space velocity is 0.6h -1 ～1.2h -1 .
  8. 8. The combined production process for co-producing needle coke and low-sulfur petroleum coke according to claim 1, wherein the distillation range of the hydrogenated wax oil in the step (1) is 310-540 ℃, and the sulfur content of the hydrogenated wax oil is not more than 0.4wt%.
  9. 9. The combined production process for co-producing needle coke and low-sulfur petroleum coke according to claim 1, wherein the distillation range of the hydrogenated wax oil in the step (1) is 350-510 ℃, and the sulfur content of the hydrogenated wax oil is not more than 0.35wt%.
  10. 10. The combined production process for co-producing needle coke and low sulfur petroleum coke according to claim 1, wherein the sulfur content of the hydrogenated tail oil is not more than 0.4wt%.
  11. 11. The combined production process for co-producing needle coke and low sulfur petroleum coke according to claim 1, wherein the sulfur content of the hydrogenated tail oil is not more than 0.35wt%.
  12. 12. The combined production process for co-producing needle coke and low-sulfur petroleum coke according to claim 1, wherein the carrier gas in the step (2) is one or more of steam, nitrogen and inert gas.
  13. 13. The combined production process for co-producing needle coke and low-sulfur petroleum coke according to claim 1, wherein the carrier gas in the step (2) is water vapor.
  14. 14. The combined production process for co-producing needle coke and low-sulfur petroleum coke according to claim 1 is characterized in that the reaction condition of the cracking treatment unit in the step (2) is that the reaction temperature is 420-490 ℃, the reaction pressure is 0.2-1.0 MPa, and the residence time is 0.1-3 h.
  15. 15. The combined production process for co-producing needle coke and low-sulfur petroleum coke according to claim 12 or 13, wherein the mass ratio of hydrogenated wax oil to water vapor is 100:0.1-100:20.
  16. 16. The combined production process for co-producing needle coke and low-sulfur petroleum coke according to claim 12 or 13, wherein the mass ratio of hydrogenated wax oil to water vapor is 100:1-100:8.
  17. 17. The combined production process for co-producing needle coke and low-sulfur petroleum coke according to claim 1, wherein the light oil discharging device in the step (2) is used for treating the light oil discharged from the needle coke and the low-sulfur petroleum coke, or is used for treating the light oil discharged from the hydrotreating unit, or is used for treating the low-sulfur petroleum coke, or is used for treating the light oil discharged from the needle coke and the low-sulfur petroleum coke.
  18. 18. The combined production process for co-producing needle coke and low-sulfur petroleum coke according to claim 1, wherein the light oil in the step (2) is partially fed into a hydrotreating unit for treatment, and partially fed into a low-sulfur petroleum coke production unit for treatment.
  19. 19. The combined production process for co-producing needle coke and low-sulfur petroleum coke according to claim 1, wherein the distillation range of middle distillate in the step (2) is 350-500 ℃.
  20. 20. The combined production process for co-producing needle coke and low-sulfur petroleum coke according to claim 1, wherein the reaction condition of the needle coke production unit in the step (3) is that the outlet temperature of a heating furnace is 420-560 ℃, the top pressure of a coke tower is 0.01-2.5 MPa, and the reaction period is 10-72 h.

Description

Combined production process and production system for co-producing needle coke and low-sulfur petroleum coke Technical Field The invention belongs to the technical field of petroleum coke production, and particularly relates to a method and a system for producing needle coke and low-sulfur petroleum coke from aromatic-rich oil. Background In delayed coking reactions, aromatics, gums and asphaltenes are the effective components for producing petroleum coke, while vacuum residuum with high gum and asphaltene content tend to be very sulfur-rich, resulting in sulfur content of petroleum coke greater than 0.5 wt.% and thus cannot be used to produce low sulfur petroleum coke. Ethylene tar is rich in aromatic hydrocarbon and colloid, has very low sulfur content, and is a high-quality raw material for producing low-sulfur petroleum coke. Needle coke is one of the low sulfur petroleum cokes, but is affected by its properties and preparation process, and it is necessary to use aromatic-rich oil with low gum content as a raw material, such as catalytic slurry oil. CN104449799a discloses a method for producing high-purity petroleum coke by using ethylene tar, which comprises mixing ethylene tar and light component oil according to a mass ratio of 1:0.05-1:0.2, and then delivering the mixture to a delayed coking device to produce high-purity petroleum coke. The method mixes the ethylene tar with the light component oil, and aims to relieve the coking tendency of the ethylene tar in the heating furnace. CN109207186a discloses a method for preparing liquid and/or coke by processing ethylene tar through delayed coking, wherein 300-500 ℃ fraction of ethylene tar is mixed with coking raw materials, wherein the coking raw materials are at least one of catalytic slurry oil, vacuum residue oil, thick oil and the like, ethylene tar accounts for 15% -45% of the total mass of the mixed oil, and the mixed oil is fed as a delayed coking device. CN105623734a discloses a method for preparing needle coke raw material, mixing catalytic slurry oil and coking raw material, injecting into coke tower to make delayed coking reaction, separating oil gas to obtain wax oil component, then hydrotreating wax oil component, and separating obtained hydrogenated product to obtain needle coke raw material. Because the ethylene tar contains aromatic olefin, the thermal stability is poor, and the aromatic olefin is easy to be condensed into coke under the high temperature condition, so that the long-period operation of the coking device is influenced. The catalytic slurry oil is subjected to hydrodesulfurization treatment, and meanwhile, partial aromatic rings are saturated to alkyl side chains, and the aromatic hydrocarbon with a large number of alkyl side chains breaks off or is aromatized during coking, so that the catalytic slurry oil plays a role of a hydrogen donor, blocks the polymerization reaction process and influences the performance of needle coke products. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a combined production process and a production system for co-producing needle coke and low-sulfur petroleum coke, which can effectively solve the problem of excessive hydrogen supply of hydrogenated slurry oil in the production process of the needle coke and the problem of short start-up period of a delayed coking device caused by poor thermal stability of ethylene tar. The first aspect of the invention provides a combined production process for co-producing needle coke and low-sulfur petroleum coke, which comprises the following steps: (1) Mixing catalytic slurry oil and ethylene tar, entering a hydrotreating unit, carrying out hydrogenation reaction under the action of hydrogen and a hydrogenation catalyst, and separating hydrogenation reaction products to obtain gas, naphtha, hydrogenated wax oil and hydrogenated tail oil; (2) The hydrogenated wax oil obtained in the step (1) enters a cracking treatment unit, and is subjected to cracking reaction under the action of carrier gas, and light oil, middle distillate and residual oil are obtained after separation of a cracking reaction product; (3) The middle distillate oil obtained in the step (2) is taken as needle coke raw material to enter a needle coke production unit, and needle coke is obtained after reaction; (4) And (3) mixing the hydrogenated tail oil obtained in the step (1) and the residual oil obtained in the step (2) to enter a low-sulfur petroleum coke production unit, and reacting to obtain the low-sulfur petroleum coke. In the combined production process for co-producing needle coke and low-sulfur petroleum coke, the catalytic slurry oil in the step (1) is preferably subjected to solid removal treatment, and the solid removal treatment can be one or a combination of several modes of filtration, centrifugal sedimentation, flocculation sedimentation, electrostatic adsorption and the like, and preferably adopts a filtration mode. Further, in