Preparation method of coal-based isotropic carbon

Abstract

The invention aims to provide a preparation method of coal-based isotropic carbon, and the isotropic degree of a carbon material is adjusted according to different application fields. According to the method, coal-based pitch is used as a raw material, an organic quinoline insoluble substance is proportionally mixed, a fraction section before anthracene oil is removed through normal pressure or reduced pressure distillation, and the mixture is heated to 470-500 DEG C again to prepare isotropic carbon. The method has the advantages that the thermal reaction process is controlled through the added quinoline insoluble substance, so that the isotropic degree of the carbon material is improved; the application range of the raw materials is widened, the raw materials with poor reaction activity are modified, and the reaction activity is improved; and various performance indexes of the product can be adjusted according to different application fields. The invention provides a simple, economic and efficient method for preparing isotropic carbon.

Description

Technical Field

[0001] The invention relates to the field of new processes for preparing isotropic carbon, and in particular to a method for preparing coal-based isotropic carbon. Background Art

[0002] Isotropic carbon is a high-quality carbon material with the characteristics of high strength, high density, high thermal conductivity, etc. Its application areas include new high-end materials such as nuclear graphite, semiconductor silicon and photovoltaic industry, mold graphite, etc. It is also a high-end carbon material in the fields of atomic energy and aerospace.

[0003] The purpose of the present invention is to provide a new and practical way to produce coal-based isotropic carbon materials. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing coal-based isotropic carbon, and the isotropy degree of the carbon material can be adjusted according to different application fields. The method is to use coal-based pitch as a raw material and a proportion of quinoline insoluble matter, remove the fraction before anthracene oil by normal pressure or reduced pressure distillation, and heat it again to 470-500°C to prepare isotropic carbon.

[0005] The preparation method of coal-based isotropic carbon material is characterized by: adding quinoline insolubles through the formula to make the coal-based pitch quickly absorb the mother liquid in the form of "crystal nuclei" during the cracking and condensation reaction, and matching the appropriate reaction conditions so that the small spheres do not have time to grow, and finally solidify the required microstructure, adjust the isotropy of the carbon material, so that it can be applied in different fields. The preparation method is as follows:

[0006] 1. Raw material preparation

[0007] Straight-run asphalt, medium-temperature asphalt or modified asphalt is prepared into raw asphalt according to the formula ratio of 1:3:1, and then added with decrystallized anthracene oil to adjust the softening point to 43-65℃. The preparation temperature is controlled at 125±5℃, and the pressure is prepared at normal pressure. The cycle is 24 hours, and the raw asphalt is circulated once as a whole. The asphalt indicators after preparation are as follows:

[0008]

[0009] 2. Production method

[0010] Under a pressure of 2Mpa, the raw asphalt and the quinoline insoluble matter are stirred and mixed in a ratio of 5-15%:85-95% (the temperature of the raw asphalt is 120-150°C, and the temperature of the quinoline insoluble matter is 80-100°C).

[0011] Furthermore, after mixing, it is transported to a preheating furnace and heated to 280-350°C before entering an atmospheric distillation tower to cut out the light, phenol, naphthalene and washing components before the anthracene oil fraction. The top temperature of the tower is 200-270°C, and it is cooled to 30-60°C by a water cooler before entering the atmospheric tower separation tank.

[0012] Furthermore, the mixed material after the light component is removed enters a heating furnace (steam is injected into the pipeline to prevent the material from coking due to reaction, the steam injection ratio is 2.5-3% of the material, the steam temperature is above 280°C, and the pressure is 4Mpa) and is heated to 470-500°C, and then enters a carbonization tower, the reaction pressure is 0.25Mpa, and the carbonization time is 24±4hr.

[0013] The advantages of the present invention are that the process is simple, the degree of isotropy of the isotropic carbon material is relatively adjustable, and the product can be applied in multiple directions.

[0014] The advantages and positive effects of the present invention are:

[0015] 1. The thermal reaction process is controlled by adding quinoline insolubles to improve the isotropy of the carbon material;

[0016] 2. Improve the application scope of raw materials, modify raw materials with poor reactivity and improve their reactivity;

[0017] 3. The performance indicators of the product can be adjusted according to different application fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Production flow chart of the present invention;

[0019] Figure 2 Microstructure of the product after adding 5% quinoline insoluble matter;

[0020] Figure 3 Microstructure of the product after adding 10% quinoline insoluble matter;

[0021] Figure 4 Microstructure of the product after adding 15% quinoline insoluble matter;

[0022] In the figure: D-1, asphalt tank; D-2, anthracene oil tank; D-3, raw material tank; D-4, quinoline tank; D-5, homogenizing tank; D-6, atmospheric pressure tower separation tank D-7, positive pressure tower separation tank; F-1, preheating furnace; F-2, heating furnace; T-1, atmospheric pressure distillation tower; T-2, positive pressure distillation tower; T-3, carbonization tower P-1, asphalt pump; P-2, anthracene oil pump; P-3, raw material pump; P-4, preheating pump; P-5, heating pump; P-6, light oil pump; P-7, heavy oil pump. DETAILED DESCRIPTION

[0023] Next, the specific implementation of the present invention will be further described in conjunction with the accompanying drawings.

[0024] 1. Raw material preparation

[0025] Straight-run asphalt, medium-temperature asphalt or modified asphalt is prepared into raw asphalt according to the formula ratio of 1:3:1, and then added with decrystallized anthracene oil to adjust the softening point to 43-65℃. The preparation temperature is controlled at 125±5℃, and the pressure is prepared at normal pressure. The cycle is 24 hours, and the raw asphalt is circulated once as a whole. The asphalt indicators after preparation are as follows:

[0026] Softening point: 43-65℃;

[0027] Density (100℃): 1.18-1.22g / cm3;

[0028] Quinoline insoluble matter: 0-5%;

[0029] β component: 8-12%;

[0030] Ash content: <0.2%;

[0031] Sulfur content: <0.5%;

[0032] Nitrogen content: <1.0%.

[0033] 2. Production method

[0034] First, the raw asphalt in the formulated raw material tank D-3 and the quinoline insoluble matter (temperature 80-100°C) in the quinoline tank D-4 are homogenously mixed in the pipeline through pump P-3 at a ratio of 5-15%:85-95% and then enter the homogenization tank D-5 for stirring. The raw asphalt temperature is 120-150°C and the pressure is 2Mpa to form a mixture.

[0035] Furthermore, the mixture is transported to the preheating furnace F-1 via pump P-4, heated to 280-350°C and enters the atmospheric distillation tower T-1, where the light, phenol, naphthalene and washing components before the anthracene oil fraction are cut out, the top temperature is 200-270°C, and the mixture is cooled to 30-60°C via water cooler E-1 and enters the atmospheric tower separation tank D-6, where the light component oil is a by-product, and the non-condensable gas and coal gas are collected together with the non-condensable gas of the positive pressure tower separation tank as coking coal gas.

[0036] Furthermore, the mixed material after the light component is removed is transported by pump P-6 into heating furnace F-2 (steam is injected into the pipeline to prevent the material from coking due to reaction, the steam injection ratio is 2.5-3% of the material, the steam temperature is above 280°C, and the pressure is 4Mpa), heated to 470-500°C, and enters carbonization tower T-2, the reaction pressure is 0.25Mpa, and special carbon materials with different degrees of isotropy are formed according to the amount of quinoline insoluble matter added.

[0037] Furthermore, the vapor-liquid medium at 440-470°C at the top of the carbonization tower T-2 enters the secondary distillation tower T-3 to recover the oil products cracked by the carbonization reaction. The pressure of the positive pressure distillation tower is 0.2Mpa, and the reflux can be adjusted to control the temperature of each layer of the tower plate, 350-380°C at the bottom of the tower, 320-340°C in the middle, and 132-164°C at the top of the tower. The gas phase of the positive pressure distillation tower passes through the water cooler E-2, and the temperature drops to 30-60°C before entering the positive pressure tower separation tank to recover different fractions of oil as by-products. The non-condensable gas and coal gas and the non-condensable gas of the atmospheric pressure tower separation tank are uniformly collected as coking coal gas.

[0038] 3. Implementation results

[0039] The results of the three ratios of adding quinoline insolubles are listed below:

[0040]

Claims

1. A method for preparing coal-based isotropic carbon, characterized in that: Coal-based asphalt is used as raw material and organic quinoline insoluble matter is added. The fraction before anthracene oil is removed by normal pressure or reduced pressure distillation and heated to 470-500°C to prepare isotropic carbon.

2. The method for preparing coal-based isotropic carbon according to claim 1, characterized in that: The raw materials are straight-run asphalt, medium-temperature asphalt and modified asphalt mixed in a ratio of 1:3:1, and are prepared by adding decrystallized anthracene oil and circulating for 24 hours at 125±5°C and normal pressure.

3. The method for preparing coal-based isotropic carbon according to claim 1, characterized in that: The asphalt indexes after the raw materials are prepared are as follows: softening point: 43-65°C; density (100°C): 1.18-1.22 g / cm3; quinoline insoluble matter: 0-5%; β component: 8-12%; Ash content: <0.2%; Sulfur content: <0.5%; Nitrogen content: <1.0%.

4. The method for preparing coal-based isotropic carbon according to claim 1, characterized in that: Under a pressure of 2Mpa, the raw material asphalt and the quinoline insoluble matter are stirred and mixed in a ratio of 5-15%:85-95% (the temperature of the raw material asphalt is 120-150°C, and the temperature of the quinoline insoluble matter is 80-100°C); after mixing, they are transported to a preheating furnace and heated to 280-350°C before entering a normal pressure distillation tower, and the light, phenol, naphthalene and washing components before the anthracene oil fraction are cut out. The tower top temperature is 200-270°C, and the mixture is cooled to 30-60°C by a water cooler and enters a separation tank of the normal pressure tower; the mixture after the light component is cut out enters a heating furnace (pipeline steam is injected to prevent the material from reacting and coking, the steam injection ratio is 2.5-3% of the material, the steam temperature is above 280°C, and the pressure is 4Mpa) and is heated to 470-500°C, and then enters a carbonization tower, the reaction pressure is 0.25Mpa, and the carbonization time is 24±4hr.

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