Coal tar pitch quality separation treatment method for preparing nuclear graphite material
阅读说明：本技术 一种制备核石墨材料的煤沥青分质处理方法 (Coal tar pitch quality separation treatment method for preparing nuclear graphite material ) 是由 叶保卫 蔡闯 于银萍 马婵 赵亚楠 李荣娇 张淼 张微 徐超 于 2020-12-30 设计创作，主要内容包括：本发明公开了一种制备核石墨材料的煤沥青分质处理方法。该方法通过对煤沥青进行分质处理,得到粘结剂沥青、精制沥青和浸渍剂沥青,搭配中间相碳微球、热裂解炭黑、石墨粉用于制备核石墨材料。本发明可提高核石墨品质的同时,减少煤沥青低附加值产品的产生,可实现煤沥青高效利用,促进煤沥青深加工产业的发展。(The invention discloses a coal tar pitch quality-separating treatment method for preparing a nuclear graphite material. The method comprises the steps of carrying out quality grading treatment on coal pitch to obtain binder pitch, refined pitch and impregnant pitch, and matching mesophase carbon microspheres, thermal cracking carbon black and graphite powder to prepare the nuclear graphite material. The method can improve the quality of the nuclear graphite, reduce the production of low value-added products of the coal pitch, realize the high-efficiency utilization of the coal pitch and promote the development of the coal pitch deep processing industry.)
1. A coal tar pitch separation processing method for preparing nuclear graphite material is characterized by comprising the following steps:
(1) the mixture of kerosene and wash oil is used as a mixed solvent to be uniformly stirred with coal pitch in a mixing container, and then the mixture is kept stand and separated to obtain a light phase substance and a heavy phase substance;
(2) flashing the light phase substance at a vacuum degree of-0.06 MPa to-0.09 MPa and a tower top temperature of 90 ℃ to 140 ℃ to obtain refined asphalt; carrying out flash evaporation on the heavy phase substance at the vacuum degree of-0.07 MPa to-0.10 MPa and the tower top temperature of 100 ℃ to 150 ℃ to obtain binder asphalt;
(3) taking 10-30% of refined asphalt obtained in the step (2), distilling under reduced pressure at the temperature of 340-370 ℃ and the vacuum degree of-0.08 MPa-0.1 MPa for 1-2 h to obtain impregnant asphalt;
(4) the coal pitch is subjected to quality grading treatment to obtain binder pitch, refined pitch and impregnant pitch, and the binder pitch, the refined pitch and the impregnant pitch are matched with mesophase carbon microspheres, thermal cracking carbon black and graphite powder to prepare the nuclear graphite material.
2. The coal tar pitch separation processing method for preparing the nuclear graphite material as claimed in claim 1, wherein the mass ratio of the mixed solvent, the kerosene and the wash oil is 0.8-1: 1, and the mass ratio of the mixed solvent and the coal tar pitch is 0.5-2.5: 1.
3. The coal tar pitch separation method for preparing nuclear graphite material according to claim 1, wherein the coal tar pitch has a softening point of 30-46 ℃ and a density of 1.18g/cm at 100 ℃3～1.22g/cm3Quinoline insoluble matter is less than 3%, toluene insoluble matter is 8-15%, coking value is greater than 32%, ash content is less than 0.3%, sulfur content is less than 0.5%, nitrogen content is less than 1%, mass fraction of distillate before 270 ℃ is less than 3%, and mass fraction of distillate before 360 ℃ is greater than 12%.
4. A method as claimed in claim 1The coal tar pitch separate processing method for preparing the nuclear graphite material is characterized in that the refined pitch has a softening point of 30-40 ℃, quinoline insoluble substances of less than 0.2 percent, toluene insoluble substances of 4-7 percent, a coking value of 30-35 percent and a density of 1.16g/cm3～1.18g/cm3Ash content is less than 0.1%.
5. The coal tar pitch separation processing method for preparing nuclear graphite material according to claim 1, wherein the binder pitch has a softening point of 90-110 ℃, quinoline insoluble content of 10-15%, toluene insoluble content of more than 50%, and density of more than 1.3g/cm3Ash content is less than 0.2%.
6. The coal tar pitch separation processing method for preparing the nuclear graphite material as claimed in claim 1, wherein the impregnant pitch has a softening point of 85-110 ℃, quinoline insoluble content of less than 0.1%, toluene insoluble content of 10-15%, coking value of 45-55%, volatile content of 60-70% and ash content of less than 0.1%.
7. The coal tar pitch fractionation process for preparing nuclear graphite material according to claim 1, wherein the nuclear graphite material has a density of 1.70g/cm3～1.80g/cm3The compressive strength is more than or equal to 50MPa, the breaking strength is more than or equal to 25MPa, the tensile strength is more than or equal to 20MPa, and the elastic modulus is 8 GPa-13 GPa.
8. The coal tar pitch separation processing method for preparing the nuclear graphite material according to claim 1, characterized in that the nuclear graphite material is prepared by adopting the following technical steps:
(1) preparing needle coke, heating the refined asphalt to 490-520 ℃ through a tubular heating furnace, sending the refined asphalt into a coking tower for cracking and polycondensation reaction for 36-37 h, and completing carbonaceous intermediate phase conversion and gas flow coke drawing to form raw coke; calcining the green coke at 1400-1500 ℃ by adopting a rotary kiln to obtain needle coke;
(2) preparing aggregate, namely taking 50-55% of needle coke, 20-30% of mesocarbon microbeads, 10-15% of graphite powder and 10-15% of thermal cracking carbon black according to the mass percentage, wherein the mass percentage of the four materials is 100%; grinding the four raw materials into powder of 100-400 meshes respectively, and then carrying out dry mixing at the temperature of 200-250 ℃ for 1-2 h to obtain aggregate;
(3) kneading, wherein 65-70% of the aggregate obtained in the step (1) and 30-35% of the binder asphalt are taken according to the mass percentage, the binder asphalt is preheated to 200 +/-20 ℃, the aggregate is added in three times, and kneading is carried out at the temperature of 150-200 ℃ for 2-3 h to obtain a kneaded material;
(4) performing secondary crushing, namely cooling the material obtained in the step (3) to 30 +/-5 ℃, and crushing the material to fine powder of less than 400 meshes to obtain powder;
(5) forming, namely pressing the fine powder obtained in the step (4) for 30-60 min at the pressure of 120-180 MPa to form a forming material;
(6) roasting, namely roasting the formed material obtained in the step (5) at 1100-1300 ℃ for 9-12 days to obtain a roasted material;
(7) dipping, preheating the roasted material obtained in the step (6) to 180-200 ℃, preserving heat for 10-11 h, putting the roasted material into a dipping tank, controlling the pressure in the tank to be-0.08 MPa to-0.1 MPa, and maintaining the pressure for 2-2.5 h; adding impregnant asphalt preheated to 200 +/-20 ℃, submerging the roasted materials in the tank, controlling the impregnation temperature to be 350-450 ℃, the pressure to be 3-6 MPa, and the time to be 5-10 h to obtain an impregnation material;
(8) secondary roasting, wherein the impregnated material obtained in the step (7) is roasted under the condition of air isolation, the roasting temperature rise process is 0-300 ℃, and the temperature rise rate is 1.5-2 ℃/h; the temperature is 300-500 ℃, and the heating rate is 0.8-1 ℃/h; the temperature is 500-800 ℃, and the heating rate is 0.6-0.8 ℃/h; the temperature is 800-1200 ℃, and the heating rate is 1.5-2 ℃/h; roasting for 60-80 h at the temperature of 1200 +/-50 ℃ to obtain a secondary roasting material;
(9) and (4) graphitizing, namely graphitizing the secondary roasting material obtained in the step (8), wherein the graphitization temperature is 2800-3000 ℃, and the temperature is kept constant for 1-2 days to obtain the nuclear graphite.
9. According toThe method of claim 1, wherein the needle coke has a true density of greater than 2.12g/cm3The volatile component is less than 8 percent, the ash content is less than 0.4 percent, the sulfur content is less than 0.1 percent, the nitrogen content is less than 0.6 percent, and the moisture content is less than 0.1 percent.
Technical Field
The invention belongs to the technical field of carbon materials, and relates to a coal tar pitch quality separation treatment method for preparing a nuclear graphite material.
Background
Coal pitch is a bulk residue of coal tar extracted by distillation, and the yield is generally 50-60%. The processing and utilization level of the coal tar pitch is very important for improving the added value of the coal tar processed product. The guidance catalog of the adjustment of the industrial structure of the Committee for the national development and improvement of the people's republic of China No. 29, which is implemented in 2020, indicates that: the research and the application of technologies such as high added value utilization of coal tar, coal tar carbon-based materials, needle coke preparation from coal pitch and the like are encouraged.
The coal pitch has high carbon content, good fluidity and easy graphitization, and can be used for producing building materials, adhesives, impregnants, carbon products and the like. At present, the coal tar pitch production capacity in China is high, the supply of medium and low-end coal tar pitch products is excessive, coal tar pitch-based high-added-value products are produced, and the expansion of the application field of the coal tar pitch-based high-added-value products is an important way for promoting the coal tar pitch industry.
The nuclear graphite is a key material of the high-temperature gas cooled reactor, and the coal pitch is one of the main factors influencing the performance of the nuclear graphite, so that the selection and the use method of the coal pitch directly determine the performance of the nuclear graphite. At present, aiming at the aspect of nuclear graphite preparation, a quality-grading and efficient utilization technology capable of improving the quality of the nuclear graphite and increasing the additional value of coal pitch is lacked.
Disclosure of Invention
The invention aims to provide a coal tar pitch quality separation treatment method for preparing a nuclear graphite material, which improves the quality of nuclear graphite, reduces low value-added products of coal tar pitch, can realize high-efficiency utilization of the coal tar pitch and promotes the development of the coal tar pitch deep processing industry.
In order to achieve the purpose, the invention is realized by adopting the following technical scheme.
A coal tar pitch separation treatment method for preparing nuclear graphite materials comprises the following steps:
(1) the mixture of kerosene and wash oil is used as a mixed solvent to be uniformly stirred with coal pitch in a mixing container, and then the mixture is kept stand and separated to obtain a light phase substance and a heavy phase substance;
(2) flashing the light phase substance at a vacuum degree of-0.06 MPa to-0.09 MPa and a tower top temperature of 90 ℃ to 140 ℃ to obtain refined asphalt; carrying out flash evaporation on the heavy phase substance at the vacuum degree of-0.07 MPa to-0.10 MPa and the tower top temperature of 100 ℃ to 150 ℃ to obtain binder asphalt;
(3) taking 10-30% of refined asphalt obtained in the step (2), distilling under reduced pressure at the temperature of 340-370 ℃ and the vacuum degree of-0.08 MPa-0.1 MPa for 1-2 h to obtain impregnant asphalt;
(4) the coal pitch is subjected to quality grading treatment to obtain binder pitch, refined pitch and impregnant pitch, and the binder pitch, the refined pitch and the impregnant pitch are matched with mesophase carbon microspheres, thermal cracking carbon black and graphite powder to prepare the nuclear graphite material.
The mass ratio of the kerosene to the washing oil of the mixed solvent is 0.8-1: 1, and the mass ratio of the mixed solvent to the coal pitch is 0.5-2.5: 1.
The coal tar pitch has a softening point of 30-46 ℃ and a density of 1.18g/cm at 100 DEG C3～1.22g/cm3Quinoline insoluble matter is less than 3%, toluene insoluble matter is 8-15%, coking value is greater than 32%, ash content is less than 0.3%, sulfur content is less than 0.5%, nitrogen content is less than 1%, mass fraction of distillate before 270 ℃ is less than 3%, and mass fraction of distillate before 360 ℃ is greater than 12%.
The refined asphalt has a softening point of 30-40 ℃, quinoline insoluble substances of less than 0.2 percent, toluene insoluble substances of 4-7 percent, a coking value of 30-35 percent and a density of 1.16g/cm3～1.18g/cm3Ash content is less than 0.1%.
The softening point of the binder asphalt is 90-110 ℃, the quinoline insoluble substance is 10-15 percent, the toluene insoluble substance is more than 50 percent, and the density is more than 1.3g/cm3Ash content is less than 0.2%.
The impregnant asphalt has a softening point of 85-110 ℃, quinoline insoluble substances of less than 0.1 percent, toluene insoluble substances of 10-15 percent, a coking value of 45-55 percent, volatile components of 60-70 percent and ash content of less than 0.1 percent.
The nuclear graphite material is denseDegree of 1.70g/cm3～1.80g/cm3The compressive strength is more than or equal to 50MPa, the breaking strength is more than or equal to 25MPa, the tensile strength is more than or equal to 20MPa, and the elastic modulus is 8 GPa-13 GPa.
The preparation of the nuclear graphite material adopts the following technical steps:
(1) preparing needle coke, heating the refined asphalt to 490-520 ℃ through a tubular heating furnace, sending the refined asphalt into a coking tower for cracking and polycondensation reaction for 36-37 h, and completing carbonaceous intermediate phase conversion and gas flow coke drawing to form raw coke; calcining the green coke at 1400-1500 ℃ by adopting a rotary kiln to obtain needle coke;
(2) preparing aggregate, namely taking 50-55% of needle coke, 20-30% of mesocarbon microbeads, 10-15% of graphite powder and 10-15% of thermal cracking carbon black according to the mass percentage, wherein the mass percentage of the four materials is 100%; grinding the four raw materials into powder of 100-400 meshes respectively, and then carrying out dry mixing at the temperature of 200-250 ℃ for 1-2 h to obtain aggregate;
(3) kneading, wherein 65-70% of the aggregate obtained in the step (1) and 30-35% of the binder asphalt are taken according to the mass percentage, the binder asphalt is preheated to 200 +/-20 ℃, the aggregate is added in three times, and kneading is carried out at the temperature of 150-200 ℃ for 2-3 h to obtain a kneaded material;
(4) performing secondary crushing, namely cooling the material obtained in the step (3) to 30 +/-5 ℃, and crushing the material to fine powder of less than 400 meshes to obtain powder;
(5) forming, namely pressing the fine powder obtained in the step (4) for 30-60 min at the pressure of 120-180 MPa to form a forming material;
(6) roasting, namely roasting the formed material obtained in the step (5) at 1100-1300 ℃ for 9-12 days to obtain a roasted material;
(7) dipping, preheating the roasted material obtained in the step (6) to 180-200 ℃, preserving heat for 10-11 h, putting the roasted material into a dipping tank, controlling the pressure in the tank to be-0.08 MPa to-0.1 MPa, and maintaining the pressure for 2-2.5 h; adding impregnant asphalt preheated to 200 +/-20 ℃, submerging the roasted materials in the tank, controlling the impregnation temperature to be 350-450 ℃, the pressure to be 3-6 MPa, and the time to be 5-10 h to obtain an impregnation material;
(8) secondary roasting, wherein the impregnated material obtained in the step (7) is roasted under the condition of air isolation, the roasting temperature rise process is 0-300 ℃, and the temperature rise rate is 1.5-2 ℃/h; the temperature is 300-500 ℃, and the heating rate is 0.8-1 ℃/h; the temperature is 500-800 ℃, and the heating rate is 0.6-0.8 ℃/h; the temperature is 800-1200 ℃, and the heating rate is 1.5-2 ℃/h; roasting for 60-80 h at the temperature of 1200 +/-50 ℃ to obtain a secondary roasting material;
(9) and (4) graphitizing, namely graphitizing the secondary roasting material obtained in the step (8), wherein the graphitization temperature is 2800-3000 ℃, and the temperature is kept constant for 1-2 days to obtain the nuclear graphite.
The needle coke has a true density of more than 2.12g/cm3The volatile component is less than 8 percent, the ash content is less than 0.4 percent, the sulfur content is less than 0.1 percent, the nitrogen content is less than 0.6 percent, and the moisture content is less than 0.1 percent.
Compared with the prior art, the invention has the beneficial effects that:
the invention can improve the quality of the nuclear graphite, reduce the low value-added products of the coal pitch, realize the high-efficiency utilization of the coal pitch and promote the development of the coal pitch deep processing industry.
Drawings
FIG. 1 is a flow chart of the process of the present invention.
Detailed Description
The present invention is described in detail below with reference to specific examples, but the use and purpose of these exemplary embodiments are merely to exemplify the present invention, and do not set forth any limitation on the actual scope of the present invention in any form, and the scope of the present invention is not limited thereto.
[ examples ] A method for producing a compound
A coal tar pitch separation treatment method for preparing nuclear graphite materials comprises the following steps:
(1) the mixture of kerosene and wash oil is used as a mixed solvent to be uniformly stirred with coal pitch in a mixing container, and then the mixture is kept stand and separated to obtain a light phase substance and a heavy phase substance;
(2) flashing the light phase substance at the vacuum degree of-0.07 MPa and the tower top temperature of 110 ℃ to obtain refined asphalt; carrying out flash evaporation on the heavy phase substance at the vacuum degree of-0.09 MPa and the tower top temperature of 150 ℃ to obtain binder asphalt;
(3) taking 18% of refined asphalt obtained in the step (2), distilling at 350 ℃ and the vacuum degree of-0.09 MPa under reduced pressure for 2 hours to obtain impregnant asphalt;
(4) the coal pitch is subjected to quality separation treatment to obtain binder pitch, refined pitch and impregnant pitch, and the binder pitch, the refined pitch and the impregnant pitch are matched with mesophase carbon microspheres, thermal cracking carbon black and graphite powder to prepare the nuclear graphite material, wherein the process flow is shown in figure 1.
The mass ratio of the mixed solvent, the kerosene and the wash oil is 0.8:1, and the mass ratio of the mixed solvent to the coal tar pitch is 1.6: 1.
The coal tar pitch has a softening point of 39 ℃ and a density of 1.191g/cm at 100 DEG C3Quinoline insoluble matter 1.89%, toluene insoluble matter 9.7%, coking value 33.5%, ash 0.05%, sulfur content 0.42%, nitrogen content 0.68%, mass fraction of distillate before 270 deg.c 2.3%, mass fraction of distillate before 360 deg.c 29%.
The refined pitch had a softening point of 32 ℃, a quinoline insoluble content of 0.02%, a toluene insoluble content of 6.6%, a coking value of 32.7%, and a density of 1.177g/cm3And ash content is 0.01%.
The softening point of the binder asphalt is 95 ℃, the quinoline insoluble substance is 11.3 percent, the toluene insoluble substance is 54.7 percent, and the density is 1.354g/cm3And ash content is 0.01%.
The impregnant pitch has a softening point of 90 ℃, a trace amount of quinoline insoluble substances, 11.2% of toluene insoluble substances, a coking value of 50.6%, 67.3% of volatile components and 0.01% of ash.
The density of the nuclear graphite material is 1.76g/cm3The compression strength is 52MPa, the breaking strength is 25MPa, the tensile strength is 23MPa, and the elastic modulus is 10 GPa.
The preparation of the nuclear graphite material adopts the following technical steps:
(1) preparing needle coke, heating the refined asphalt to 500 ℃ through a tubular heating furnace, sending the refined asphalt into a coking tower for cracking and polycondensation reaction for 36 hours, and completing carbonaceous intermediate phase conversion and gas flow coke drawing to form raw coke; calcining the green coke at 1450 ℃ by adopting a rotary kiln to obtain needle coke;
(2) preparing aggregate, namely taking 52% of needle coke, 23% of mesocarbon microbeads, 15% of graphite powder and 10% of thermal cracking carbon black according to the mass percentage, wherein the mass percentage of the four materials is 100%; grinding the four raw materials into powder of 100-400 meshes respectively, and then carrying out dry mixing at 200 ℃ for 2 hours to obtain aggregate;
(3) kneading, namely taking 67% of the aggregate obtained in the step (1) and 33% of the binder asphalt according to mass percentage, heating the binder asphalt to 200 ℃, adding the aggregate into the binder asphalt in three times, and kneading at 200 ℃ for 2 hours to obtain a kneaded material;
(4) performing secondary crushing, namely cooling the material obtained in the step (3) to 30 ℃, and crushing the material to fine powder with the granularity less than 400 meshes to obtain powder;
(5) molding, namely pressing the fine powder obtained in the step (4) for 50min under the pressure of 160MPa to obtain a molding material;
(6) roasting, namely roasting the formed material obtained in the step (5) at 1200 ℃ for 10 days to obtain a roasted material;
(7) dipping, namely preheating the roasted material obtained in the step (6) to 190 ℃, preserving heat for 10 hours, then placing the roasted material into a dipping tank, controlling the pressure in the tank to be-0.1 MPa, and maintaining the pressure for 2 hours; adding impregnant asphalt preheated to 200 ℃, submerging the roasted materials in the tank, and controlling the impregnation temperature to be 400 ℃, the pressure to be 5MPa and the time to be 8 hours to obtain an impregnated material;
(8) secondary roasting, wherein the impregnated material obtained in the step (6) is roasted under the condition of air isolation, the roasting temperature rise process is 0-300 ℃, and the temperature rise rate is 1.6 ℃/h; 300-500 ℃, the heating rate is 0.8 ℃/h; the temperature is 500-800 ℃, and the heating rate is 0.7 ℃/h; 800-1200 ℃, and the heating rate is 1.7 ℃/h; roasting at 1200 ℃ for 70h to obtain a secondary roasting material;
(9) and (4) graphitizing, namely graphitizing the secondary roasting material obtained in the step (8), wherein the graphitization temperature is 2800-3000 ℃, and the temperature is kept constant for 1-2 days to obtain the nuclear graphite.
The needle coke has a true density of 2.124g/cm3Volatile component 7.6%, ash 0.06%, sulfur content 0.04%, nitrogen content0.44% and 0.07% water.