CN110343535B

CN110343535B - Process for directly preparing needle coke by coal

Info

Publication number: CN110343535B
Application number: CN201910625411.2A
Authority: CN
Inventors: 郭少青; 曹艳芝; 高丽兵; 卫贤贤
Original assignee: Taiyuan University of Science and Technology
Current assignee: Taiyuan University of Science and Technology
Priority date: 2019-07-11
Filing date: 2019-07-11
Publication date: 2020-11-24
Anticipated expiration: 2039-07-11
Also published as: CN110343535A

Abstract

The invention discloses a process for directly preparing needle coke by coal. The method comprises the following steps: (1) a first asphalting unit: crushing and drying coal, mixing the crushed and dried coal with hydrogenation solvent oil, and then carrying out an asphalt reaction; (2) a first solid-liquid separation unit: mixing the material after the asphaltization reaction with the fraction from the fractionating unit, and then carrying out solid-liquid separation; (3) a second asphalting unit: carrying out an asphaltization reaction; (4) a second solid-liquid separation unit: carrying out solid-liquid separation; (5) a fractionation unit: fractionating the liquid from the first and second solid-liquid separation units in a fractionation column into fractions of different temperatures; (6) a pre-hydrogenation unit: carrying out catalytic pre-hydrogenation to obtain hydrogenation solvent oil; (7) pre-polycondensation unit: carrying out pre-polycondensation to obtain a pre-polycondensation polymer; (8) a coking unit: carrying out coking reaction to obtain needle coke green coke; (9) a calcination unit: and calcining at high temperature to obtain needle coke finished products. The invention directly uses coal to prepare needle coke, and realizes effective high-value utilization of coal.

Description

Process for directly preparing needle coke by coal

Technical Field

The invention relates to a process for directly preparing needle coke by using coal, belonging to the technical field of needle coke preparation.

Background

The needle coke is a high-quality variety which is greatly developed in carbon materials, has the appearance of a silver gray porous solid with metallic luster, has an obvious flowing texture in structure, has large and few holes and is slightly elliptical, has larger length-width ratio of particles, has fibrous or needle-shaped texture trend, and is a raw material for producing high-end carbon products such as ultrahigh-power graphite electrodes, lithium battery cathode materials, special carbon materials, nuclear graphite and the like. Because the needle coke has good graphitization performance, the ultrahigh-power graphite electrode produced by using the needle coke has the advantages of low resistivity, large volume density, high mechanical strength, small thermal expansion coefficient, good thermal shock resistance and the like, the production enterprises of the needle coke are gradually increased, and the yield is also increased year by year. The needle coke is classified into oil-based needle coke and coal-based needle coke according to the difference of raw materials. The coal-based needle coke is mainly prepared from coal tar pitch which is mainly derived from coal tar byproduct in the coal coking process. The coal-based needle coke cannot be produced by using coal pitch as a raw material at present, for example, chinese patent CN 200910198177.6 (method and system for producing coal-based needle coke) removes quinoline insoluble substances from coal pitch, and then the coal pitch is used as a raw material for producing needle coke. However, with the increase of needle coke enterprises and the expansion of yield, coal pitch produced by the coking industry cannot meet the requirements of needle coke production, so that other alternative raw materials are needed to be adopted to produce needle coke to relieve the contradiction of insufficient raw materials for needle coke production.

Disclosure of Invention

The invention aims to provide a process for directly preparing needle coke by coal, which is based on the principle that coal is converted into aromatic compounds suitable for producing the needle coke by a certain means, and then the aromatic compounds are subjected to proper coking and calcining processes to prepare the needle coke. The invention obviously enlarges the raw material range for producing the needle coke; meanwhile, the materials and energy generated in the process are effectively utilized, the yield of the needle coke is improved by additionally arranging a pre-polycondensation mode, and the method has multiple benefits of environmental protection, economy and the like.

The invention provides a process for directly preparing needle coke by coal, which comprises the following specific steps:

(1) a first asphalting unit: the coal is crushed, dried and finely ground to be below 100 meshes, mixed with hydrogenation solvent oil from a pre-hydrogenation unit, heated to 350-480 ℃ and then enters an asphalt reactor for asphalt reaction.

(2) A first solid-liquid separation unit: introducing the material after the asphaltization reaction into a first solid-liquid separation unit, mixing the material with the fraction at the temperature of less than 210 ℃ and the fraction at the temperature of 210-300 ℃ from the fractionation unit, and then carrying out solid-liquid separation, wherein the separated liquid enters the fractionation unit, and the solid enters a second asphaltization unit.

(3) A second asphalting unit: mixing the solid separated by the first solid-liquid separation unit with the hydrogenation solvent oil from the pre-hydrogenation unit, heating to 350-480 ℃, and then carrying out an asphalt reaction.

(4) A second solid-liquid separation unit: introducing the material reacted by the second asphaltization unit into a second solid-liquid separation unit, mixing the material with the fraction at the temperature of less than 210 ℃ and the fraction at the temperature of 210-300 ℃ from the fractionation unit, carrying out solid-liquid separation, allowing the separated liquid to enter the fractionation unit, allowing 20-70% of the separated solid mass to enter the first asphaltization unit, allowing 20-78% of the separated solid mass to enter the second asphaltization unit, and allowing the rest part to be used as a byproduct for other purposes.

(5) A fractionation unit: the liquid from the first and second solid-liquid separation units is fractionated in a fractionation column into four components of a fraction at less than 210 ℃, a fraction at 210 ℃ and 300 ℃, a fraction at 300 ℃ and 360 ℃ and a fraction at more than 360 ℃; 30-70% of the mass of the fraction at the temperature of less than 210 ℃ is sent to a first solid-liquid separation unit, and 30-70% is sent to a second solid-liquid separation unit; 10-60% of the mass of the fraction at 300 ℃ of 210 ℃ enters a first solid-liquid separation unit, 10-70% enters a second solid-liquid separation unit, and the rest enters a pre-hydrogenation unit; 10-70% of the mass of the fraction at 360 ℃ under 300-; and (3) a fraction decoking unit at the temperature of more than 360 ℃.

(6) A pre-hydrogenation unit: and carrying out catalytic pre-hydrogenation on the 210-300 ℃ fraction and the 300-360 ℃ fraction from the fractionation unit to obtain the hydrogenation solvent oil.

(7) Pre-polycondensation unit: the 300-360 ℃ fraction from the fractionation unit is subjected to pre-polycondensation to obtain a pre-polycondensation polymer.

(8) A coking unit: the 300-360 ℃ fraction and the more than 360 ℃ fraction from the fractionation unit and the precondensate from the precondensate unit are mixed in a ratio of 1-10: 1-20: mixing in a ratio of 0.1-10, and coking in a coking unit to obtain needle coke green coke; introducing the liquid oil product by-product of the coking unit into a fractionating unit for fractionating.

(9) A calcination unit: and calcining the needle coke green coke at high temperature to obtain a needle coke calcined coke finished product.

In the method, in the first and second asphalting units, the mass ratio of solids (both coal dust and solid products from the solid-liquid separation unit) to hydrogenated solvent oil is 1: 0.1-5, the asphaltization temperature is 350-.

In the method, an iron catalyst or a nickel-molybdenum-cobalt catalyst with the mass percent of 0.01-30% of the materials is added in the process of asphaltization.

In the method, the fractionating unit is general equipment in the petrochemical industry, such as a fractionating tower, and can separate the liquid from the solid-liquid separation unit into a fraction at a temperature of less than 210 ℃, a fraction at a temperature of 210 ℃ and 300 ℃, a fraction at a temperature of 300 ℃ and 360 ℃ and a fraction at a temperature of more than 360 ℃.

In the method, the hydrogenation reaction temperature of the pre-hydrogenation unit is 280-380 ℃, the hydrogenation reaction pressure is 5-15MPa, and the hydrogenation catalyst is a nickel-molybdenum catalyst.

In the method, the pre-polycondensation unit is a high-pressure reactor with controllable temperature and pressure, the pre-polycondensation pressure is controlled to be 0.1MPa to 8MPa, the temperature is 280 ℃ and 460 ℃, and the time is 0.1 to 10 hours.

In the method, the coking unit controls the coking reaction pressure to be 0.1-1 MPa, the temperature to be 420-520 ℃ and the reaction time to be 3-40 hours.

In the method, the calcination temperature is controlled to 1250-.

The first solid-liquid separation unit and the second solid-liquid separation unit can be gravity settling equipment or centrifugal settling equipment, or the combination of the gravity settling equipment and the centrifugal settling equipment.

The calcining unit is a conventional calcining device used for producing needle coke, and can be a box type calcining furnace, a tank type furnace or a rotary kiln.

The invention has the beneficial effects that:

1) the process of the invention widens the raw material range of needle coke production, is easy to realize industrial production, and provides a new process for the production of needle coke.

2) Effectively utilizes the materials and energy generated in the process, improves the yield of the needle coke, and has multiple benefits of environmental protection, economy and the like.

Drawings

FIG. 1 is a process flow diagram for the direct production of needle coke from coal.

Detailed Description

The present invention is further illustrated by, but is not limited to, the following examples.

Example 1:

(1) crushing, drying and finely grinding coal to be below 100 meshes, wherein the mass mixing ratio of the coal to hydrogenated solvent oil from a pre-hydrogenation unit is 1: 0.1, heating to 480 ℃, then entering an asphaltization reactor, adding an iron catalyst accounting for 30 mass percent of the material under the hydrogen pressure of 30MPa, and then carrying out the asphaltization reaction for 0.01 min. (2) Introducing the material after the asphaltization reaction into a first solid-liquid separation unit, mixing the material with the fraction at the temperature of less than 210 ℃ and the fraction at the temperature of 210-300 ℃ from the fractionation unit, then carrying out gravity settling type solid-liquid separation, introducing the separated liquid into the fractionation unit, and introducing the separated solid into a second asphaltization unit. (3) And mixing the solid separated by the first solid-liquid separation unit with the hydrogenated solvent oil from the pre-hydrogenation unit in a mass mixing ratio of 1: 0.5, heating to 460 ℃, entering an asphalt reactor, adding an iron catalyst with the mass percent of 1% of the materials under the hydrogen pressure of 15MPa, and then carrying out asphalt reaction for 1 min. (4) Introducing the material after the second asphaltization reaction into a second solid-liquid separation unit, mixing the material with the fraction at the temperature of less than 210 ℃ and the fraction at the temperature of 210-300 ℃ from the fractionation unit, then carrying out gravity settling type solid-liquid separation, introducing the separated liquid into the fractionation unit, introducing 30% of the separated solid mass into the first asphaltization unit, introducing 60% into the second asphaltization unit, and discharging the rest part out of the system as a byproduct. (5) The liquid from the first and second solid-liquid separation units is fractionated in the fractionation column into a fraction at less than 210 ℃, a fraction at 210-; 30 percent of the mass of the fraction at the temperature of less than 210 ℃ is sent to a first solid-liquid separation unit, and 70 percent is sent to a second solid-liquid separation unit; 60 percent of the mass of the fraction at the temperature of 300 ℃ at 210 ℃ enters a first solid-liquid separation unit, 10 percent of the mass enters a second solid-liquid separation unit, and the rest enters a pre-hydrogenation unit; 10 percent of the mass of the fraction at the temperature of 300 ℃ and 360 ℃ is removed from a pre-hydrogenation unit, 80 percent of the mass of the fraction is removed from a coking unit, and the rest part of the mass of the fraction is removed from a pre-polycondensation unit; and (3) a fraction decoking unit at the temperature of more than 360 ℃. (6) And carrying out catalytic pre-hydrogenation on the 210-300 ℃ fraction and the 300-360 ℃ fraction from the fractionation unit under the conditions of 5MPa, 350 ℃ and the presence of a nickel-molybdenum catalyst to obtain the hydrogenation solvent oil. (7) The 300-360 ℃ fraction from the fractionation unit is subjected to pre-polycondensation reaction for 1 hour at 0.1MPa and 360 ℃ to obtain a pre-polycondensation polymer. (8) The 300-360 ℃ fraction and the greater than 360 ℃ fraction from the fractionation unit and the precondensate from the precondensation unit are mixed in a ratio of 1: 3: after being mixed according to the proportion of 0.2, the mixture enters a coking unit to carry out temperature and pressure changing coking reaction for 20 hours at the temperature of between 0.1 and 1MPa and between 420 and 520 ℃ to obtain needle coke green coke. Introducing the liquid oil product by-product of the coking unit into a fractionating unit for fractionating. (9) And (3) calcining the needle coke green coke in a box type calcining furnace at 1500 ℃ for 5 hours to obtain a needle coke calcined coke finished product.

Example 2

(1) Crushing, drying and finely grinding coal to be below 100 meshes, wherein the mass mixing ratio of the coal to hydrogenated solvent oil from a pre-hydrogenation unit is 1: 5, heating to 350 ℃ after mixing, then entering an asphaltization reactor, and carrying out an asphaltization reaction for 15min after adding a nickel-molybdenum-cobalt catalyst with the mass percent of 1% of the materials under the hydrogen pressure of 10 MPa. (2) Introducing the material after the asphaltization reaction into a first solid-liquid separation unit, mixing the material with the fraction at the temperature of less than 210 ℃ and the fraction at the temperature of 210-300 ℃ from the fractionation unit, and then carrying out centrifugal sedimentation type solid-liquid separation, wherein the separated liquid enters the fractionation unit, and the separated solid enters a second asphaltization unit. (3) And mixing the solid separated by the first solid-liquid separation unit with the hydrogenated solvent oil from the pre-hydrogenation unit in a mass mixing ratio of 1: 1, heating to 380 ℃, then entering an asphalt reactor, and carrying out asphalt reaction for 5min after adding a nickel-molybdenum-cobalt catalyst with the mass percent of 1% of the material under the hydrogen pressure of 15 MPa. (4) Introducing the material after the second asphaltization reaction into a second solid-liquid separation unit, mixing the material with the fraction at the temperature of less than 210 ℃ and the fraction at the temperature of 210-300 ℃ from the fractionation unit, and then carrying out centrifugal settling type solid-liquid separation, wherein the separated liquid enters the fractionation unit, 50% of the mass of the separated solid enters the first asphaltization unit, 40% of the mass of the separated solid enters the second asphaltization unit, and the rest part of the separated solid is discharged from the system to be used as a byproduct. (5) The liquid from the first and second solid-liquid separation units is fractionated in the fractionation column into a fraction at less than 210 ℃, a fraction at 210-; 70 percent of the mass of the fraction at the temperature of less than 210 ℃ is sent to a first solid-liquid separation unit, and 30 percent is sent to a second solid-liquid separation unit; 10 percent of the mass of the fraction at the temperature of 300 ℃ at 210 ℃ enters a first solid-liquid separation unit, 70 percent of the mass enters a second solid-liquid separation unit, and the rest enters a pre-hydrogenation unit; 70 percent of the mass of the fraction at the temperature of 300 ℃ and 360 ℃ is removed from a pre-hydrogenation unit, 10 percent of the mass of the fraction is removed from a coking unit, and the rest part of the mass of the fraction is removed from a pre-polycondensation unit; and (3) a fraction decoking unit at the temperature of more than 360 ℃. (6) And carrying out catalytic pre-hydrogenation on the 210-300 ℃ fraction and the 300-360 ℃ fraction from the fractionation unit under the conditions of 15MPa, 280 ℃ and the presence of a nickel-molybdenum catalyst to obtain the hydrogenation solvent oil. (7) The 300-360 ℃ fraction from the fractionation unit is subjected to pre-polycondensation reaction for 3 hours at 8MPa and 280 ℃ to obtain a pre-polycondensation polymer. (8) The 300-360 ℃ fraction and the greater than 360 ℃ fraction from the fractionation unit and the precondensate from the precondensation unit are mixed in a ratio of 1: 2.5: after being mixed according to the proportion of 0.5, the mixture enters a coking unit to carry out temperature and pressure changing coking reaction for 5 hours at the temperature of between 0.1 and 1MPa and between 420 and 520 ℃ to obtain needle coke green coke. Introducing the liquid oil product by-product of the coking unit into a fractionating unit for fractionating. (9) And (3) calcining the needle coke green coke in a box type calcining furnace at 1500 ℃ for 1 hour to obtain a needle coke calcined coke finished product.

Example 3

(1) Crushing, drying and finely grinding coal to be below 100 meshes, wherein the mass mixing ratio of the coal to hydrogenated solvent oil from a pre-hydrogenation unit is 1: 0.5, heating to 430 ℃ after mixing, then entering an asphaltization reactor, and carrying out an asphaltization reaction for 30min under the hydrogen pressure of 5MPa and after adding an iron catalyst accounting for 5 mass percent of the materials. (2) Introducing the material after the asphaltization reaction into a first solid-liquid separation unit, mixing the material with the fraction at the temperature of less than 210 ℃ and the fraction at the temperature of 210-300 ℃ from the fractionation unit, then carrying out gravity settling type solid-liquid separation, introducing the separated liquid into the fractionation unit, and introducing the separated solid into a second asphaltization unit. (3) And mixing the solid separated by the first solid-liquid separation unit with the hydrogenated solvent oil from the pre-hydrogenation unit in a mass mixing ratio of 1: 2 heating to 400 ℃ after mixing, then entering an asphaltization reactor, and carrying out an asphaltization reaction for 0.05min under the hydrogen pressure of 20MPa and after adding an iron catalyst with the mass percent of 3%. (4) Introducing the material after the second asphaltization reaction into a second solid-liquid separation unit, mixing the material with the fraction at the temperature of less than 210 ℃ and the fraction at the temperature of 210-300 ℃ from the fractionation unit, then carrying out gravity settling type solid-liquid separation, introducing the separated liquid into the fractionation unit, introducing 30% of the separated solid mass into the first asphaltization unit, introducing 50% into the second asphaltization unit, and discharging the rest part out of the system as a byproduct. (5) The liquid from the first and second solid-liquid separation units is fractionated in the fractionation column into a fraction at less than 210 ℃, a fraction at 210-; 40 percent of the mass of the fraction at the temperature of less than 210 ℃ is sent to a first solid-liquid separation unit, and 60 percent is sent to a second solid-liquid separation unit; 30 percent of the mass of the fraction at the temperature of 300 ℃ at 210 ℃ is sent to a first solid-liquid separation unit, 40 percent is sent to a second solid-liquid separation unit, and the rest is sent to a pre-hydrogenation unit; 30 percent of the mass of the fraction at 300-360 ℃ is removed from a pre-hydrogenation unit, 50 percent of the mass of the fraction is removed from a coking unit, and the rest is removed from a pre-polycondensation unit; and (3) a fraction decoking unit at the temperature of more than 360 ℃. (6) And carrying out catalytic pre-hydrogenation on the 210-300 ℃ fraction and the 300-360 ℃ fraction from the fractionation unit under the conditions of 15MPa, 280 ℃ and the presence of a nickel-molybdenum catalyst to obtain the hydrogenation solvent oil. (7) The 300-360 ℃ fraction from the fractionation unit is subjected to a pre-polycondensation reaction for 5 hours at 0.1MPa and 460 ℃ to obtain a pre-polycondensation polymer. (8) The 300-360 ℃ fraction and the greater than 360 ℃ fraction from the fractionation unit and the precondensate from the precondensation unit are mixed in a ratio of 1: 2: 1, then the mixture enters a coking unit to carry out temperature and pressure swing coking reaction for 30 hours at the temperature of between 0.1 and 1MPa and between 420 and 520 ℃ to obtain needle coke green coke. Introducing the liquid oil product by-product of the coking unit into a fractionating unit for fractionating. (9) And calcining the needle coke green coke at 1450 ℃ for 2 hours in a rotary kiln to obtain a needle coke calcined coke finished product.

Example 4

(1) Crushing, drying and finely grinding coal to be below 100 meshes, wherein the mass mixing ratio of the coal to hydrogenated solvent oil from a pre-hydrogenation unit is 1: 2 heating to 420 ℃ after mixing, then entering an asphaltization reactor, and carrying out an asphaltization reaction for 10min under the hydrogen pressure of 3MPa and after adding an iron catalyst with the mass percent of 2% of the materials. (2) Introducing the material after the asphaltization reaction into a first solid-liquid separation unit, mixing the material with the fraction at the temperature of less than 210 ℃ and the fraction at the temperature of 210-300 ℃ from the fractionation unit, and then carrying out centrifugal sedimentation type solid-liquid separation, wherein the separated liquid enters the fractionation unit, and the separated solid enters a second asphaltization unit. (3) And mixing the solid separated by the first solid-liquid separation unit with the hydrogenated solvent oil from the pre-hydrogenation unit in a mass mixing ratio of 1: 1, heating to 400 ℃ after mixing, then entering an asphaltization reactor, and carrying out an asphaltization reaction for 20min under the hydrogen pressure of 2MPa and after adding an iron catalyst with the mass percent of 5% of the materials. (4) Introducing the material after the second asphaltization reaction into a second solid-liquid separation unit, mixing the material with the fraction at the temperature of less than 210 ℃ and the fraction at the temperature of 210-300 ℃ from the fractionation unit, and then carrying out centrifugal settling type solid-liquid separation, wherein the separated liquid enters the fractionation unit, 70% of the mass of the separated solid enters the first asphaltization unit, 20% of the mass of the separated solid enters the second asphaltization unit, and the rest part of the separated solid is discharged from the system to be used as a byproduct. (5) The liquid from the first and second solid-liquid separation units is fractionated in the fractionation column into a fraction at less than 210 ℃, a fraction at 210-; 50 percent of the mass of the fraction at the temperature of less than 210 ℃ is sent to a first solid-liquid separation unit, and 50 percent is sent to a second solid-liquid separation unit; 40 percent of the mass of the fraction at the temperature of 300 ℃ at 210 ℃ enters a first solid-liquid separation unit, 40 percent enters a second solid-liquid separation unit, and the rest enters a pre-hydrogenation unit; 30 percent of the mass of the fraction at 300-360 ℃ is removed from a pre-hydrogenation unit, 50 percent of the mass of the fraction is removed from a coking unit, and the rest is removed from a pre-polycondensation unit; and (3) a fraction decoking unit at the temperature of more than 360 ℃. (6) And carrying out catalytic pre-hydrogenation on the 210-300 ℃ fraction and the 300-360 ℃ fraction from the fractionation unit under the conditions of 13 MPa, 290 ℃ and the presence of a nickel-molybdenum catalyst to obtain the hydrogenation solvent oil. (7) The 300-360 ℃ fraction from the fractionation unit is subjected to pre-polycondensation reaction for 1 hour at 4 MPa and 360 ℃ to obtain a pre-polycondensation polymer. (8) The 300-360 ℃ fraction and the greater than 360 ℃ fraction from the fractionation unit and the precondensate from the precondensation unit are mixed in a ratio of 1: 1: 1.5, then entering a coking unit to carry out temperature and pressure changing coking reaction for 3 hours at the temperature of between 0.1 and 1MPa and at the temperature of between 420 and 520 ℃ to obtain needle coke green coke. Introducing the liquid oil product by-product of the coking unit into a fractionating unit for fractionating. (9) And (3) calcining the needle coke green coke in a box type calcining furnace at 1250 ℃ for 24 hours to obtain a needle coke calcined coke finished product.

Example 5

(1) Crushing, drying and finely grinding coal to be below 100 meshes, wherein the mass mixing ratio of the coal to hydrogenated solvent oil from a pre-hydrogenation unit is 1: 3 heating to 350 ℃ after mixing, then entering an asphaltization reactor, and carrying out an asphaltization reaction for 0.01min under the hydrogen pressure of 30MPa and after adding an iron catalyst with the mass percent of 0.01% of the materials. (2) Introducing the material after the asphaltization reaction into a first solid-liquid separation unit, mixing the material with the fraction at the temperature of less than 210 ℃ and the fraction at the temperature of 210-300 ℃ from the fractionation unit, and then carrying out centrifugal sedimentation type solid-liquid separation, wherein the separated liquid enters the fractionation unit, and the separated solid enters a second asphaltization unit. (3) And mixing the solid separated by the first solid-liquid separation unit with the hydrogenated solvent oil from the pre-hydrogenation unit in a mass mixing ratio of 1: 0.1, heating to 480 ℃, then entering an asphaltization reactor, and carrying out an asphaltization reaction for 5min under the hydrogen pressure of 20MPa and adding an iron catalyst with the mass percent of 10% of the materials. (4) Introducing the material after the second asphaltization reaction into a second solid-liquid separation unit, mixing the material with the fraction at the temperature of less than 210 ℃ and the fraction at the temperature of 210-300 ℃ from the fractionation unit, then carrying out gravity settling type solid-liquid separation, introducing the separated liquid into the fractionation unit, introducing 20% of the separated solid mass into the first asphaltization unit, introducing 78% into the second asphaltization unit, and discharging the rest part out of the system as a byproduct. (5) The liquid from the first and second solid-liquid separation units is fractionated in the fractionation column into a fraction at less than 210 ℃, a fraction at 210-; 60 percent of the mass of the fraction at the temperature of less than 210 ℃ is sent to a first solid-liquid separation unit, and 40 percent is sent to a second solid-liquid separation unit; 40 percent of the mass of the fraction at the temperature of 300 ℃ at 210 ℃ enters a first solid-liquid separation unit, 30 percent of the mass enters a second solid-liquid separation unit, and the rest enters a pre-hydrogenation unit; 50 percent of the mass of the fraction at the temperature of 300 ℃ and 360 ℃ is removed from a pre-hydrogenation unit, 40 percent of the mass of the fraction is removed from a coking unit, and the rest part of the mass of the fraction is removed from a pre-polycondensation unit; and (3) a fraction decoking unit at the temperature of more than 360 ℃. (6) And carrying out catalytic pre-hydrogenation on the 210-300 ℃ fraction and the 300-360 ℃ fraction from the fractionation unit under the conditions of 12 MPa, 300 ℃ and the presence of a nickel-molybdenum catalyst to obtain the hydrogenation solvent oil. (7) The 300-360 ℃ fraction from the fractionation unit is subjected to a pre-polycondensation reaction for 5 hours at 0.3MPa and 350 ℃ to obtain a pre-polycondensation polymer. (8) The 300-360 ℃ fraction and the greater than 360 ℃ fraction from the fractionation unit and the precondensate from the precondensation unit are mixed in a ratio of 1: 2.5: after being mixed according to the proportion of 0.5, the mixture enters a coking unit to carry out temperature and pressure changing coking reaction for 3 hours at the temperature of between 0.1 and 1MPa and at the temperature of between 420 and 520 ℃ to obtain needle coke green coke. Introducing the liquid oil product by-product of the coking unit into a fractionating unit for fractionating. (9) And calcining the needle coke green coke in a pot furnace at 1350 ℃ for 20 hours to obtain a needle coke calcined coke finished product.

Example 6

(1) Crushing, drying and finely grinding coal to be below 100 meshes, wherein the mass mixing ratio of the coal to hydrogenated solvent oil from a pre-hydrogenation unit is 1: 0.5, heating to 450 ℃, then entering an asphalt reactor, adding a nickel-molybdenum-cobalt catalyst with the mass percent of 0.01 percent of the material under the hydrogen pressure of 20MPa, and then carrying out asphalt reaction for 300 min. (2) Introducing the material after the asphaltization reaction into a first solid-liquid separation unit, mixing the material with the fraction at the temperature of less than 210 ℃ and the fraction at the temperature of 210-300 ℃ from the fractionation unit, then carrying out gravity settling type solid-liquid separation, introducing the separated liquid into the fractionation unit, and introducing the separated solid into a second asphaltization unit. (3) And mixing the solid separated by the first solid-liquid separation unit with the hydrogenated solvent oil from the pre-hydrogenation unit in a mass mixing ratio of 1: 2 heating to 390 ℃ after mixing, then entering an asphaltization reactor, and carrying out an asphaltization reaction for 50min under the hydrogen pressure of 8MPa and after adding a nickel-molybdenum-cobalt catalyst with the mass percent of the materials being 0.1%. (4) Introducing the material after the second asphaltization reaction into a second solid-liquid separation unit, mixing the material with the fraction at the temperature of less than 210 ℃ and the fraction at the temperature of 210-300 ℃ from the fractionation unit, and then carrying out centrifugal settling type solid-liquid separation, wherein the separated liquid enters the fractionation unit, 70% of the mass of the separated solid enters the first asphaltization unit, 20% of the mass of the separated solid enters the second asphaltization unit, and the rest part of the separated solid is discharged from the system to be used as a byproduct. (5) The liquid from the first and second solid-liquid separation units is fractionated in the fractionation column into a fraction at less than 210 ℃, a fraction at 210-; 65 percent of the mass of the fraction at the temperature of less than 210 ℃ is sent to a first solid-liquid separation unit, and 35 percent is sent to a second solid-liquid separation unit; 40 percent of the mass of the fraction at the temperature of 300 ℃ at 210 ℃ enters a first solid-liquid separation unit, 30 percent of the mass enters a second solid-liquid separation unit, and the rest enters a pre-hydrogenation unit; 45 percent of the mass of the fraction at 300-; and (3) a fraction decoking unit at the temperature of more than 360 ℃. (6) And carrying out catalytic pre-hydrogenation on the 210-300 ℃ fraction and the 300-360 ℃ fraction from the fractionation unit at the temperature of 5MPa and 370 ℃ in the presence of a nickel-molybdenum catalyst to obtain the hydrogenation solvent oil. (7) The 300-360 ℃ fraction from the fractionation unit is subjected to pre-polycondensation reaction for 3 hours at 4 MPa and 430 ℃ to obtain a pre-polycondensation polymer. (8) The 300-360 ℃ fraction and the greater than 360 ℃ fraction from the fractionation unit and the precondensate from the precondensation unit are mixed in a ratio of 1: 2: 1, then the mixture enters a coking unit to carry out temperature and pressure swing coking reaction for 30 hours at the temperature of between 0.1 and 1MPa and between 420 and 520 ℃ to obtain needle coke green coke. Introducing the liquid oil product by-product of the coking unit into a fractionating unit for fractionating. (9) And calcining the needle coke green coke in a box-type calcining furnace at 1250-1500 ℃ for 1-24 hours to obtain a needle coke calcined coke finished product.

Claims

1. A process for directly preparing needle coke by using coal is characterized by comprising the following steps: the method comprises the following steps:

(1) a first asphalting unit: crushing, drying and finely grinding coal to be below 100 meshes, mixing the coal with hydrogenation solvent oil from a pre-hydrogenation unit, heating to 350-480 ℃, and then entering an asphalt reactor for asphalt reaction;

(2) a first solid-liquid separation unit: introducing the material after the asphaltization reaction into a first solid-liquid separation unit, mixing the material with a fraction at the temperature of less than 210 ℃ and a fraction at the temperature of 210-300 ℃ from a fractionation unit, and then carrying out solid-liquid separation, wherein the separated liquid enters the fractionation unit, and the solid enters a second asphaltization unit;

(3) a second asphalting unit: mixing the solid separated by the first solid-liquid separation unit with hydrogenation solvent oil from a pre-hydrogenation unit, heating to 350-480 ℃, and then carrying out an asphaltization reaction;

in the first asphalting unit and the second asphalting unit, the mass ratio of the solid raw material to the hydrogenated solvent oil is 1: 0.1-5, the asphaltization temperature is 350-; the solid raw materials comprise coal powder and solid products obtained by the solid-liquid separation unit;

(4) a second solid-liquid separation unit: introducing the material reacted by the second asphaltization unit into a second solid-liquid separation unit, mixing the material with the fraction at the temperature of less than 210 ℃ and the fraction at the temperature of 210-300 ℃ from the fractionation unit, and then carrying out solid-liquid separation;

the separated liquid enters a fractionation unit, 20-70% of the mass of the separated solid enters a first asphaltization unit, 20-78% of the mass of the separated solid enters a second asphaltization unit, and the rest part is used as a by-product for other purposes;

(5) a fractionation unit: the liquid from the first and second solid-liquid separation units is fractionated in a fractionation column into four components of a fraction at less than 210 ℃, a fraction at 210 ℃ and 300 ℃, a fraction at 300 ℃ and 360 ℃ and a fraction at more than 360 ℃; 30-70% of the mass of the fraction at the temperature of less than 210 ℃ is sent to a first solid-liquid separation unit, and 30-70% is sent to a second solid-liquid separation unit; 10-60% of the mass of the fraction at 300 ℃ of 210 ℃ enters a first solid-liquid separation unit, 10-70% enters a second solid-liquid separation unit, and the rest enters a pre-hydrogenation unit; 10-70% of the mass of the fraction at 360 ℃ under 300-; a fraction decoking unit at greater than 360 ℃;

(6) a pre-hydrogenation unit: carrying out catalytic pre-hydrogenation on the 210-300 ℃ fraction and the 300-360 ℃ fraction from the fractionation unit to obtain hydrogenation solvent oil;

(7) pre-polycondensation unit: the 300-360 ℃ fraction from the fractionation unit is subjected to pre-polycondensation to obtain a pre-polycondensation polymer;

(8) a coking unit: the 300-360 ℃ fraction, the more than 360 ℃ fraction and the pre-polycondensation polymer from the pre-polycondensation unit are mixed according to the mass ratio of 1-10: 1-20: mixing in the ratio of 0.1-10, and coking in a coking unit to obtain needle coke; introducing a liquid oil product by-produced in the coking unit into a fractionating unit for fractionating;

2. The process for directly preparing needle coke from coal as claimed in claim 1, wherein: in the process of asphaltization, an iron catalyst or a nickel-molybdenum-cobalt catalyst with the mass percent of 0.01-30% of the materials is added at the same time.

3. The process for directly preparing needle coke from coal as claimed in claim 1, wherein: the hydrogenation reaction temperature of the pre-hydrogenation unit is 280-380 ℃, the hydrogenation reaction pressure is 5-15MPa, and the hydrogenation catalyst is a nickel-molybdenum catalyst.

4. The process for directly preparing needle coke from coal as claimed in claim 1, wherein: the pre-polycondensation unit is a high-pressure reactor with controllable temperature and pressure, the pre-polycondensation pressure is controlled to be 0.1MPa to 8MPa, the temperature is 280 ℃ and 460 ℃, and the time is 0.1 to 10 hours.

5. The process for directly preparing needle coke from coal as claimed in claim 1, wherein: the coking unit controls the coking reaction pressure to be 0.1-1 MPa, the temperature to be 420-520 ℃ and the reaction time to be 3-40 hours.

6. The process for directly preparing needle coke from coal as claimed in claim 1, wherein: in the calcining unit, the calcining temperature is controlled to be 1250-1500 ℃, and the calcining time is controlled to be 1-24 hours.

7. The process for directly preparing needle coke from coal as claimed in claim 1, wherein: the first solid-liquid separation unit and the second solid-liquid separation unit are gravity settling equipment or centrifugal settling equipment or a combination of the gravity settling equipment and the centrifugal settling equipment.

8. The process for directly preparing needle coke from coal as claimed in claim 1, wherein: the calcining unit is a conventional calcining device used for producing needle coke and is one of a box type calcining furnace, a tank type furnace or a rotary kiln.