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A control method for microcracks on the surface of pitch-based spherical activated carbon

A technology of spherical activated carbon and control methods, which is applied in chemical instruments and methods, carbon compounds, inorganic chemistry, etc., can solve problems such as microcracks in asphalt balls containing holes, microcracks in pitch balls containing naphthalene, and escape of fine naphthalene, so as to avoid Effects of microcracks, suppression of surface microcracks, and improvement of mechanical properties

Active Publication Date: 2021-10-22
湖南曦威新材料有限公司
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AI Technical Summary

Problems solved by technology

However, when refined naphthalene is used as a group composition regulator and pore-forming agent for coal tar pitch with a high softening point, it is not only easy to cause microcracks on the surface of pitch-based spherical activated carbon, but also brings the following series of technical problems or engineering problems :
[0004] (1) Refined naphthalene is an organic substance that is volatile and easy to crystallize. During the ball formation process of naphthalene / high softening point coal tar pitch particles, refined naphthalene is easy to escape quickly from the matrix of naphthalene-containing pitch balls, resulting in the production of naphthalene-containing Microcracks appear on the surface of asphalt balls
[0005] (2) After the naphthalene / high softening point coal tar pitch particles are formed into balls, there must be a certain amount of water on the surface of the naphthalene pitch balls. In order to remove the water, drying must be carried out, and the gas phase / solid phase is affected during the drying process. Due to the influence of the concentration gradient of medium naphthalene, refined naphthalene is easy to escape from the naphthalene-containing pitch balls, which will also cause microcracks on the surface of the naphthalene-containing pitch balls
[0006] (3) In order to make the inside of the asphalt ball matrix form original pores, the prior art all adopts the method of organic solvent extraction to extract the naphthalene in the naphthalene-containing pitch ball by organic solvent, but in the extraction process, due to the organic solvent to the naphthalene The high solubility of naphthalene makes it difficult to control the removal rate of refined naphthalene from the naphthalene-containing pitch ball matrix, and will also cause microcracks on the surface of the pitch ball
[0007] (4) Although most of the refined naphthalene can be separated from the matrix of asphalt spheres after the asphalt spheres containing naphthalene are extracted with organic solvents, there is still a small amount of naphthalene due to the influence of diffusion coefficient, concentration gradient, and intermolecular chemical bonds. The refined naphthalene molecules remain in the matrix of the asphalt balls, and this part of the refined naphthalene will escape from the asphalt balls in the form of gas volatilization during the heating process of oxidation and non-melting, which will lead to the formation of porous pitch balls during the process of oxidation and non-melting. Microcracks appear on the surface

Method used

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  • A control method for microcracks on the surface of pitch-based spherical activated carbon
  • A control method for microcracks on the surface of pitch-based spherical activated carbon
  • A control method for microcracks on the surface of pitch-based spherical activated carbon

Examples

Experimental program
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Effect test

Embodiment 1

[0048] Using high softening point coal tar pitch with a softening point of 268°C as raw material, use a twin-screw extruder to uniformly mix 1000Kg of high softening point coal tar pitch and 250Kg of refined naphthalene to make naphthalene pitch strips with a diameter of 3mm. Using a roller crusher, crush 1250Kg of naphthalene pitch-containing strips into naphthalene pitch-containing particles with a diameter of 0.6-0.8mm. 3000L of deionized water, 20Kg of polyvinyl alcohol, and 500Kg of naphthalene pitch-containing particles were successively placed in a 5000L high-pressure reactor, and 99.99% high-purity nitrogen gas was introduced to keep the pressure in the reactor at 0.5 MPa. Then the reaction medium was heated to 109°C at a heating rate of 5°C / min and kept at a constant temperature for 30 minutes, and then naturally cooled to 50°C. Although the obtained product is a naphthalene-pitch ball with a diameter of 0.6-0.8 mm, there are certain microcracks on the surface, such a...

Embodiment 2

[0050] Using high softening point coal tar pitch with a softening point of 268°C as raw material, use twin-screw extruder to uniformly mix 1000Kg high softening point coal tar pitch and 250Kg refined naphthalene to make naphthalene pitch strips with a diameter of 3mm. Using a roller crusher, crush 1250Kg of naphthalene pitch-containing strips into naphthalene pitch-containing particles with a diameter of 0.6-0.8 mm. 3000L of deionized water, 20Kg of polyvinyl alcohol, 5Kg of refined naphthalene, and 500Kg of naphthalene-containing pitch particles were successively placed in a 5000L high-pressure reactor, and 99.99% high-purity nitrogen gas was introduced to keep the pressure in the reactor at 0.5MPa. Then the reaction medium was heated to 109°C at a heating rate of 5°C / min and kept at a constant temperature for 30 minutes, and then naturally cooled to 50°C. The resulting product is a naphthalene pitch-containing ball with a diameter of 0.6 to 0.8 mm, but the surface of the nap...

Embodiment 3

[0052] Place the naphthalene pitch-containing balls prepared in [Example 2] in a blast oven and dry at 60°C for 2 hours. Before drying, the surface of naphthalene pitch-containing spheres was smooth, but after drying, although the macroscopic morphology of naphthalene pitch-containing spheres did not change, slight microcracks appeared on the surface, such as Figure 4 shown.

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Abstract

The invention relates to a method for controlling microcracks on the surface of asphalt-based spherical activated carbon. By modifying coal tar pitch with a high softening point, improving the pelleting conditions of naphthalene-containing pitch particles, and changing the removal method of naphthalene in the naphthalene-containing pitch pellets, the final A pitch-based spherical activated carbon with smooth surface, no microcracks and high sphericity was obtained. Among them, the prepared pitch-based spherical activated carbon has a density of 0.5-0.85g / cm 3 , The specific surface area is 800~1300m 2 / g, vibration strength higher than 95% and microporous content higher than 83%. The invention effectively solves the problem of microcracks on the surface of the pitch-based spherical activated carbon during the preparation process, not only improves the mechanical properties of the material, but also has great significance for promoting the engineering process of the material and expanding its application field.

Description

technical field [0001] The invention relates to a method for controlling micro-cracks on the surface of asphalt-based spherical activated carbon, which belongs to a method with an anti-vibration strength higher than 95% and a specific surface area of ​​800-1300m 2 / g Surface structure control method of pitch-based spherical activated carbon. Background technique [0002] Pitch-based spherical activated carbon refers to a new type of carbonaceous porous material prepared by using high softening point coal tar pitch (softening point 240-280°C) as raw material, through spheroidization, extraction separation, oxidation infusion, carbonization and water vapor activation. . Although pitch-based spherical activated carbon is also a kind of activated carbon, its unique spherical structure and spherical diameter (0.2-1.5 mm) make it better than ordinary granular activated carbon and columnar activated carbon in terms of packing density, mechanical strength, and adsorption and desorp...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B32/336C01B32/33
CPCC01B32/33C01B32/336
Inventor 李国俊詹亮李才毅罗浩
Owner 湖南曦威新材料有限公司
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