Technology for preparing needle coke raw material from coal-tar pitch

Abstract

The invention provides a technology for preparing a needle coke raw material from coal-tar pitch. The technology comprises the following steps of 1, fully mixing asphalt and a solvent, and removing insoluble substances in the mixture by a physical separation method, wherein the solvent is a mixture of coal light oil and coal aromatic oil or is a mixture of BTX and coal aromatic oil; a mass ratio of the coal light oil or the BTX to the coal aromatic oil is in a range of (20: 80) to (95: 5); and a mass ratio of the solvent to the asphalt is in a range of 0.5 to 10, 2, feeding a clear liquor without the insoluble substances into a separator, and separating the light solvent from the clear liquor to obtain a heavy fraction having low QI, and 3, carrying out hydrotreatment on the heavy fraction in the presence of a hydrogenation catalyst at a temperature of 300 to 450 DEG C under the pressure of 5 to 20MPa. The needle coke raw material obtained by the technology has low sulfur content and a small expansion coefficient.

Description

technical field [0001] The invention belongs to the field of coal chemical industry, and in particular relates to a process for preparing coal series needle coke raw materials by utilizing coal tar pitch. Background technique [0002] Needle coke is a high-quality material for manufacturing high-power and ultra-high-power electrodes. Graphite electrodes made of needle coke have strong thermal shock resistance, high mechanical strength, good oxidation performance, low electrode consumption and large allowable current density, etc. advantage. The needle coke currently produced can be divided into two categories: petroleum-based needle coke and coal-based needle coke according to the different raw materials used. The Great Lakes Carbon Company of the United States first developed the production process of petroleum-based needle coke in the 1950s. However, due to the trend of petroleum processing towards the direction of catalytic cracking and light-weight deep processing, the ...

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Problems solved by technology

[0009] In the above process, due to the use of light component oil as a solvent, the solvent also removes a large amount of toluene-insoluble pyridine-soluble matter and pyridine-insoluble quinoline-insoluble matter (QI) in coal tar pitch. Phenyl solubles, the inventors have found through research that β 2 The presence of components is not absolutely harmful, choose an appropriate amount of β 2 The components can significantly increase the yield of needle coke and reduce the thermal expansion coefficient of needle coke without affecting the quality of needle coke, which is not recognized by those skilled in the art in the prior art. It is precisely because in the above technology, the β 2 Components are removed as much as possible, so using the above-mentioned treated coal tar pitch as a raw material to prepare needle coke, the yield is very low, and the thermal expansion coefficient of the prepared needle coke is large, which seriously affects the use of needle coke as an electrode. performance

[0010] In addition, there is still a small amount of sulfur in the pitch produced by the above process, which will remain in the needle coke prepared from the pitch. During the graphitization process of the needle coke in the manufacture of electrodes, sulfur Under high temperature conditions, gas will be generated, causing the electrode to expand, which will affect the quality of the graphite electrode

Although prolonging the time of the graphitization treatment can suppress electrode expansion to a certain extent, the prolongation of the treatment time will lead to an increase in power consumption, thereby reducing the economic benefits of the electrode preparation process

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