CN110066675B - Method for continuously producing high-quality needle coke - Google Patents
Method for continuously producing high-quality needle coke Download PDFInfo
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- CN110066675B CN110066675B CN201910336180.3A CN201910336180A CN110066675B CN 110066675 B CN110066675 B CN 110066675B CN 201910336180 A CN201910336180 A CN 201910336180A CN 110066675 B CN110066675 B CN 110066675B
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
- C10B55/00—Coking mineral oils, bitumen, tar, and the like or mixtures thereof with solid carbonaceous material
Abstract
The invention discloses a method for continuously producing high-quality needle coke, which mainly comprises the following steps: (1) the reaction raw materials are pressurized by a metering pump through a heating furnace tube and then continuously enter a carbonization reactor (high-pressure coke tower), the temperature in the carbonization reactor is maintained at 400-500 ℃, and 10E to EAnd 24h, then stopping feeding, and continuing the reaction for 0-18 h. In the whole carbonization reaction process, high-pressure-low-pressure alternative pulse operation is adopted in the carbonization reactor, and the change of reaction pressure is in the range of 1.0-6.0 MPa; (2) the raw coke generated at the bottom of the carbonization reactor is discharged from the bottom of the carbonization reactor through hydraulic decoking; (3) and calcining the green coke product at 1450 ℃ for 2-4 h to obtain the cooked coke. The method is favorable for forming a needle coke product with an optical structure in a highly uniaxial orientation fine fiber shape, the content of the mesophase of the needle coke product reaches more than 95 percent, and the CTE (coefficient of thermal expansion) of a graphite electrode prepared from the needle coke product is less than or equal to 1.3 multiplied by 10 at the temperature of 25-600 DEG C‑6V. C. Meanwhile, the process has the characteristics of simple process flow, strong operability and continuous production.
Description
Technical Field
The invention relates to the field of high-grade carbon material production processes, in particular to a continuous process for producing high-quality needle coke.
Background
The needle coke is a carbon material with more purposes, the surface has silver gray metallic luster, the section of the raw coke has optical textures distributed in a thin fibrous uniaxial way, the cooked coke has the characteristics of smaller thermal expansion coefficient and higher electrical conductivity, and the high-power electrode and the ultrahigh-power electrode made of the needle coke have small resistivity, strong heat shock resistance and higher mechanical strength, are used as high-quality carbon materials and are widely applied to electric arc furnace steelmaking, can improve the smelting efficiency by more than 3 times in the smelting industry, along with the vigorous development of the steel industry in China, the demand of needle coke is also increased day by day, and according to incomplete statistics, the needle coke product is required to be about 20 ten thousand tons every year in China, but most of the needle coke needs to be imported due to the shortage of the domestic needle coke in productivity and quality, the needle coke has good market prospect, thus arousing the attention of a plurality of scientific research institutions and scientific research personnel.
Patent CN201110035564.5 discloses a preparation method of acicular petroleum coke: putting raw oil into a test tube, putting the test tube into a tubular reaction kettle provided with a reflux section, filling inert gas to 2.2-3.5 MPa, putting the reaction kettle into heating equipment with the temperature of 300-350 ℃ for preheating for 5-10 minutes, heating the reaction kettle to the carbonization temperature of 430-480 ℃ within 5-10 seconds, discharging gas to the initial pressure within 10-15 minutes, then discharging gas to the initial pressure every 10-15 minutes, and measuring the volume of the discharged gas until carbonization is finished; and carbonizing for 12-18 hours at the temperature after the gas volume is less than 10-20 ml/10min to obtain the needle coke. Even if the needle coke with the ordered structure is prepared by adopting the gas release coking process, the released gas is defined by time, the needle coke generation process can go through different stages, the generated gas quantity can be gradually reduced along with the increase of the carbonization depth, the gas release coking process is a process in which the viscosity of an intermediate phase system and the gas quantity of light components are matched with each other, the coking effect can be influenced by the overhigh and overlow viscosity of the intermediate phase, the time is taken as the point for defining the gas release, the change of the viscosity of the intermediate phase is ignored, a large amount of body-shaped intermediate phases are generated in the later development stage of the intermediate phase, the viscosity of the system is increased along with the increase of the viscosity, and the coking effect can be influenced finally due to the shortage of the gas.
Patent ZL01140582.1 provides a process for producing needle coke by gas discharge coke drawing. Putting a coal-series raw material, a petroleum-series raw material or a copolymer raw material of the coal-series raw material and the petroleum-series raw material into a tubular reaction furnace, filling 0.1-2 MPa of inert gas, heating to the coking temperature of 480-550 ℃ within 2-30 s after sealing, releasing the gas to the original 0.2-2.0 MPa after the system pressure exceeds 0.2-1.0 MPa of the original pressure, and sealing until the pressure in the reaction furnace does not exceed 0.2-1.0 MPa of the crude oil pressure any more. And continuously coking for 4-8 hours to prepare the needle coke when the pressure in the reaction furnace is unchanged. The technology adopts a gas discharge coke-drawing process to prepare the needle coke, the released gas is defined by the pressure generated by the self-produced gas of the raw oil, but the gas yield of the intermediate phase in different stages of nucleation, growth, fusion and coke-drawing is different, for example, the gas yield in the later development stage of the intermediate phase is greatly reduced compared with the gas yield generated by the violent cracking of the raw oil in the initial reaction stage, the shearing force generated by the escape of light components in the system in the later development stage is too small in most cases, the ideal coke-drawing effect on the intermediate phase in the system cannot be achieved, and the microstructure of the needle coke cannot realize uniaxial orientation. In addition, the above 2 similar patents are all batch processes, and there is currently no continuous process for producing high quality needle coke (i.e., high mesophase content and high degree of uniaxial mesophase structure orientation).
Disclosure of Invention
Aiming at the defects of the existing needle coke preparation process, the invention provides a needle coke preparation method suitable for industrial continuous production, and the process can produce high-quality needle coke with a fine fibrous optical structure and a good uniaxial orientation degree.
The continuous process for producing high-quality needle coke comprises the following specific steps:
(1) the reaction raw materials are pressurized by a metering pump through a heating furnace tube and then continuously enter a carbonization reactor, the temperature in the carbonization reactor is maintained at 400-500 ℃, the materials are continuously fed for 10-24 hours, and then the feeding is stopped and the reaction is continuously carried out for 0-18 hours. In the whole carbonization reaction process, high-pressure-low-pressure alternative pulse operation is adopted in the carbonization reactor, and the change of reaction pressure is in the range of 1.0-6.0 MPa; (2) the light oil gas generated in the coking reaction process passes through a high-pressure separator and a low-pressure separator to obtain a liquid byproduct and a gas byproduct; (3) the green coke generated at the bottom of the carbonization reactor is discharged from the bottom of the carbonization reactor through a hydraulic decoking process. And calcining the raw coke at 1450 ℃ for 2-4 h to obtain high-quality needle coke.
The raw materials used for producing the needle coke in the step (1) are medium-low temperature coal tar, high-temperature coal tar and fractions thereof, petroleum heavy oil fractions, vacuum residual oil, FCC slurry oil and solvent extract oil of the raw oil.
In the step (1), the carbonization reactor is operated by pulse pressure swing, which specifically comprises the following steps: when the reaction pressure reaches a preset high-pressure state through a self-boosting process, after reacting for a certain time, reducing the reaction pressure to a preset low-pressure state, then entering a high-pressure state through reaction self-boosting, and performing in a circulating manner until the reaction is finished. In the whole process, reaction raw materials are continuously fed, fresh raw materials which enter the reactor later are in the initial stage of reaction, and the generated sufficient gas quantity provides sufficient coke-drawing shearing force for the generated bulk mesophase in the reactor, so that the pressure-swing operation can be realized to a greater extent, and further the airflow shearing force can be regulated and controlled to a greater extent.
The continuous process protected by the step (2) adopts a high-pressure oil-gas separation system, is suitable for large-amplitude pressure-swing and pulse pressure-swing reaction processes, can meet the requirements of high-pressure carbonization processes and low-pressure carbonization oil-gas separation, and thus ensures product separation under the pulse pressure-swing reaction process.
The ash content of the needle coke prepared in the step (3) is less than or equal to 0.4, and the true density is more than or equal to 2.13g/cm3CTE measured at 25 to 600 ℃ of not more than 1.1X 10-6V. C. The needle coke is a highly uniaxial orientation fine fibrous needle coke with an optical structure, and the content of a mesophase of the needle coke is up to 95-100%.
The invention adopts a continuous carbonization process with the characteristic of pulse pressure transformation, and the reaction process has the characteristic of integral reaction. Specifically, the raw material entering the carbonization reactor is subjected to alkyl side chain fracture of an aromatic compound at the initial stage of carbonization reaction to generate a large amount of light components, and under the high-pressure reaction, the large amount of light components are dissolved in a reaction matrix to reduce the viscosity of the reaction matrix, so that the generation and growth of mesophase globules and subsequent fusion and formation of a mesophase are facilitated; then, the light components can escape in a large amount due to pressure reduction, so that the generated body mesophase realizes the air flow coke-drawing effect, and the flaky mesophase structure is converted into a fine fiber mesophase structure which is uniaxially oriented along the longitudinal axis of the kettle body; the process also presents integral reaction characteristics because fresh raw materials continuously enter the carbonization reactor, and the raw materials subsequently entering under the pulse pressure transformation operation also undergo an evolution process similar to the evolution process of the mesophase under high pressure and then uniaxial orientation under low pressure.
Compared with the prior preparation method, the invention has the following differences: the invention adopts pulse voltage transformation operation in the continuous carbonization process, presents the characteristic of integral reaction, and can ensure that the two processes of the generation of a large-size mesophase structure and the subsequent conversion into a uniaxial orientation needle-like structure can be coupled in most stages of the reaction process.
Drawings
FIG. 1 is a process flow diagram for needle coke production.
1: a heating furnace 2: carbonization reactor
3: hot high-pressure separator 4: cold high-pressure separator
5: cold low-pressure separator 6: thermal low pressure separator
7: condenser 8: gas phase product outlet
9: liquid-phase product outlet 10: raw coke discharge port
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
The continuous process for producing high-quality needle coke comprises the following specific steps as shown in the attached drawing:
(1) raw oil enters a carbonization reactor 2 through a heating furnace 1, the temperature in the carbonization reactor is kept at 400-500 ℃, feeding is continuously carried out for 10-24 hours, and then the feeding is stopped to continuously react for 0-18 hours; carrying out pulse pressure change operation within the reaction pressure range of 1-6 MPa; (2) high-temperature oil gas generated in the coking reaction process enters a hot high-pressure separator 3 from the top of a carbonization reactor 2, liquid-phase components obtained at the lower part of the separator 3 enter a hot low-pressure separator 6 from the bottom, oil gas components at the upper part of the separator 3 enter a cold high-pressure separator 4 from the top to be further cooled into high-pressure liquid-phase products, the high-pressure liquid-phase products enter a cold low-pressure separator 5 from the bottom, and the liquid-phase products in the hot low-pressure separator 6 and the cold low-pressure separator 5 are collected into a tank 9; after the oil gas on the upper part of the cold high-pressure separator 4 is further cooled by a condenser 7, the residual gas product is discharged from a gas-phase product outlet 8; (3) the green coke generated at the bottom of the carbonization reactor 2 is discharged from a green coke discharge port 10 at the bottom of the carbonization reactor 1 through a hydraulic decoking process, and then a needle coke product is obtained through calcination.
Example 1
High-temperature coal tar is used as a feeding material of the continuous process, raw materials enter a carbonization reactor 2, the total retention time of the reaction raw materials is 18h under the protection of nitrogen, the reaction temperature is 420 ℃, pulse reaction process regulation and control are carried out in the reaction retention time, namely, after the reaction starts to control the high pressure of 1MPa to react for 3h, the pressure is reduced to 0.1MPa to react for 3h, then the pressure is increased to 1MPa to react for 3h, then the pressure is reduced to 0.1MPa to react for 3h, and then the pulse taking the pressure as a cycle is continuously carried outA reaction process, wherein the materials are continuously fed in the reaction process until the reaction period is finished; after the reaction was complete, the green coke was quickly transferred out of the carbonization reactor with a yield of 55.9% green coke, 35.3% liquid by-product and 8.8% gaseous by-product. The content of the obtained green coke mesophase is 100 percent, and the green coke is in a directional uniaxial fine fiber shape; calcining the green coke at 1450 ℃ for 2h to obtain needle coke product with ash content of 0.3, volatile content of 0.4 and true density of 2.13g/cm3And a CTE of 1.3X 10 measured at 25 to 600 ℃-6/℃。
Example 2
The low-temperature coal tar is used as the feeding material of the continuous process, the raw materials enter a carbonization reactor 2, the total retention time of the reaction raw materials is 20h under the protection of nitrogen, the reaction temperature is 430 ℃, the pulse reaction process regulation and control are carried out within the reaction retention time, namely, after the reaction starts to control the high pressure of 2MPa for reaction for 3h, the pressure is reduced to 1MPa for reaction for 3h, then the pressure is increased to 2MPa for reaction for 3h, then the pressure is reduced to 1MPa for reaction for 3h, then the pulse reaction process taking the pressure as the circulation is continuously carried out, and the feeding is continuously carried out in the reaction process until the reaction period is finished; after the reaction was complete, the green coke was quickly transferred out of the carbonization reactor with a yield of 58.7% for green coke, 33.0% for liquid by-product and 8.3% for gaseous by-product. The content of the intermediate phase of the obtained green coke is 95 percent, and the green coke is in a shape of a directional distribution uniaxial coarse fiber; calcining green coke at 1450 deg.C for 2 hr to obtain needle coke product with ash content of 0.25, volatile component of 0.3 and true density of 2.15g/cm3And a CTE of 1.3X 10 measured at 25 to 600 ℃-6/℃。
Example 3
The vacuum residue is used as the feeding material of the continuous process, the raw materials enter a carbonization reactor 2, the total residence time of the reaction raw materials is 19h under the protection of nitrogen, the reaction temperature is 435 ℃, the pulse reaction process regulation and control are carried out within the reaction residence time, namely, after the reaction starts to control the high pressure of 2MPa to react for 2.5h, the pressure is reduced to 1.5MPa to react for 2.5h, then the pressure is increased to 2MPa to react for 2.5h, then the pressure is reduced to 1.5MPa to react for 2.5h, then the pulse reaction process taking the pressure as the circulation is continuously carried out, and the feeding is continuously carried out in the reaction process until the reaction period is finished; after the reaction is finishedThe raw coke is rapidly transferred out of the carbonization reactor, the yield of the raw coke is 60.5 percent, the yield of the liquid by-product is 33.2 percent, and the yield of the gas by-product is 6.3 percent. The content of the obtained green coke mesophase is 100 percent, and the green coke is in a directional uniaxial fine fiber shape; calcining green coke at 1450 deg.C for 2 hr to obtain needle coke product with ash content of 0.25, volatile component of 0.35 and true density of 2.17g/cm3And a CTE of 1.08X 10 measured at 25 to 600 ℃-6/℃。
Example 4
Taking FCC slurry oil as the feeding material of the continuous process, feeding the raw materials into a carbonization reactor 2, under the protection of nitrogen, controlling the total retention time of the reaction raw materials to be 20h, controlling the reaction temperature to be 460 ℃, and carrying out pulse reaction process regulation and control within the reaction retention time, namely, after the reaction starts to control the high pressure of 4MPa to react for 2h, reducing the pressure to 3MPa to react for 2h, then increasing the pressure to 4MPa to react for 2h, then reducing the pressure to 3MPa to react for 2h, then continuously carrying out the pulse reaction process taking the pressure as a cycle, and continuously feeding in the reaction process until the reaction period is finished; after the reaction was complete, the green coke was quickly transferred out of the carbonization reactor with a yield of 65.9% for green coke, 27.3% for liquid by-product and 6.8% for gaseous by-product. The content of the obtained green coke mesophase is 100 percent, and the optical structure is in an oriented uniaxial coarse fiber shape; calcining the green coke at 1450 ℃ for 2h to obtain needle coke product with ash content of 0.2, volatile content of 0.33 and true density of 2.17g/cm3And a CTE of 1.15X 10 measured at 25 to 600 ℃-6/℃。
Example 5
Pumping an FCC solvent out of oil slurry as a feed of the continuous process, feeding the raw materials into a carbonization reactor 2, under the protection of nitrogen, controlling the total retention time of the reaction raw materials to be 24h, controlling the reaction temperature to be 470 ℃, and performing pulse reaction process regulation and control within the reaction retention time, namely, after the reaction starts to control the high pressure of 5MPa to react for 3h, reducing the pressure to 4MPa to react for 3h, then increasing the pressure to 5MPa to react for 3h, then reducing the pressure to 4MPa to react for 3h, then continuously performing a pulse reaction process taking the pressure as a cycle, and continuously feeding in the reaction process until the reaction period is finished; after the reaction is finished, the raw coke is quickly transferred out of the carbonization reactor, the yield of the raw coke is 68.1 percent, and the liquid by-product is collectedThe yield was 25.6% and the yield of gaseous by-products was 6.3%. The content of the obtained green coke mesophase is 95 percent, and the optical structure is in a shape of directionally distributed uniaxial fine fiber; calcining the green coke at 1450 ℃ for 2h to obtain needle coke product with ash content of 0.2, volatile content of 0.28 and true density of 2.14g/cm3And a CTE of 1.1X 10 as measured at 25 to 600 ℃-6/℃。
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (3)
1. A continuous process for producing needle coke, characterized by: (1) feeding the reaction raw materials into a carbonization reactor through a heating furnace tube, keeping the temperature in the carbonization reactor at 400-500 ℃, continuously feeding for 10-24 h, and then stopping feeding and continuously reacting for 0-18 h; in the whole carbonization reaction process, high-pressure-low-pressure alternative pulse operation is adopted in the carbonization reactor, and the change of reaction pressure is in the range of 1.0-6.0 MPa; (2) discharging the green coke generated at the bottom of the carbonization reactor from the bottom of the carbonization reactor through a hydraulic decoking process to obtain a green coke product; (3) calcining the raw coke at 1450 ℃ for 2-4 h to obtain a needle coke product;
wherein, the whole carbonization reaction process adopts pulse type pressure changing operation, namely when the pressure in the carbonization reactor reaches the preset high pressure and reacts for a certain time, the reaction pressure is reduced to the preset low pressure, the reaction is continued for a period of time, the pressure is automatically increased and the reaction enters the preset high pressure through the reaction process, and the high pressure and the low pressure are changed repeatedly until the reaction is finished.
2. The continuous process for producing needle coke as claimed in claim 1, wherein: the reaction raw materials comprise: medium and low temperature coal tar, high temperature coal tar and fractions thereof, petroleum heavy oil fractions, vacuum residuum, FCC slurry oil and solvent extract oil of the raw oil.
3. According to claim 1The continuous process for producing the needle coke is characterized by comprising the following steps of: the ash content of the needle coke obtained after calcination is less than or equal to 0.3, the volatile matter is less than or equal to 0.4, and the true density is more than or equal to 2.13g/cm3CTE measured at 25 to 600 ℃ of not more than 1.3X 10-6/℃。
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| CN109516826B (en) * | 2018-11-28 | 2021-09-28 | 辽宁丹炭科技集团有限公司 | Method for manufacturing phi 600 ultrahigh-power joint by using domestic needle coke |
| CN110734779B (en) * | 2019-10-15 | 2021-03-05 | 湖南中科星城石墨有限公司 | Isotropic coke suitable for lithium ion battery cathode raw material and preparation method thereof |
| CN111592902B (en) * | 2020-05-22 | 2021-05-28 | 中国石油大学(华东) | Method for preparing needle coke for ultrahigh-power electrode from heavy oil |
| CN113004924B (en) * | 2021-04-15 | 2023-05-12 | 山东京阳科技股份有限公司 | Needle coke production process for ultrahigh-power graphite electrode joint |
| CN113862033B (en) * | 2021-09-18 | 2023-01-13 | 中国石油大学(华东) | Method for preparing needle coke with low thermal expansion coefficient by combining fluid coking and delayed coking |
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| CN106566570B (en) * | 2016-10-21 | 2019-11-15 | 中国石油大学(华东) | A kind of method that mink cell focus prepares high-quality needle coke |
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