A method for preparing spinnable pitch from coal tar pitch

Abstract

A method for preparing spinnable pitch from coal tar pitch comprises the following steps: crushing medium-low-temperature coal tar pitch to 20 meshes or below, performing extracting by using tetrahydrofuran, performing filtration to obtain a medium-low-temperature coal tar pitch soluble component, and recovering the tetrahydrofuran solvent from the soluble component to obtain refined pitch; and mixing the refined pitch with petrolatum, adding the obtained mixture into a reactor, introducing nitrogen under normal pressure, heating the reactor to 180-220 DEG C at a heating rate of 1-10 DEG C / min, switching to air, introducing the air into the reactor at a rate of 10-60 mL / min.g, heating the reactor to 280-350 DEG C at a heating rate of 1-10 DEG C / min, and allowing the obtained mixture to stay for 1-10 h to obtain the spinnable pitch. The method has the advantages of high yield, low price and moderate thermal polycondensation temperature.

Description

technical field [0001] The invention belongs to the technical field of pitch-based carbon fibers, and in particular relates to a method for preparing spinnable pitch from coal tar pitch. [0002] technical background [0003] Since the 1980s, the carbon fiber manufacturing industry has developed rapidly. Due to its excellent electrical and thermodynamic properties, it has been widely used in many fields such as defense industry, aerospace, cutting-edge technology, and daily life. Foreign countries already have the capacity of commercial production, but our country is still in the stage of research and trial production. Because the United States, Japan, and Germany control it as a strategic material, it seriously restricts the development of my country's national defense and other related fields. Therefore, it is of strategic significance to accelerate the research and development of carbon fiber. [0004] In order to realize the technology of preparing general-purpose pitch...

AI Technical Summary

Problems solved by technology

Among them, high-temperature thermal polymerization has a large range of modification treatment for coal tar pitch and is easy to operate, but the softening point of pitch is not significantly improved, and the softening point of pitch after polymerization is widely distributed, the yield is low, and the fluidity is poor, which is not conducive to melt spinning; direct oxidation heat Polymerization can effectively improve the softening point of spinning pitch, and the yield of pitch is high, but after the introduction of air or oxygen, a large amount of non-condensable gas will be discharged with pitch fume, the operating environment is harsh and the degree of reaction is not easy to control; while catalytic synthesis and cross-linking synthesis The reaction temperature of the method is severe and difficult to control, and the commonly used catalysts are corrosive to the equipment, and the residual catalyst after the reaction will also affect the subsequent spinning and carbonization processes; hydrogenation modification thermal polymerization can usually produce high-quality spinning pitch, but the currently commonly used The hydrogen-donating solvent is tetrahydronaphthalene. Due to its low boiling point (207.2°C), it is easy to be entrained and lost by gas during high-temperature thermal polymerization, resulting in insufficient hydrogen supply during polymerization. When using high polymers such as PVC and PS as hydrogen-donating substances , its pyrolysis temperature is high, and free radicals cannot react with asphalt at low temperature

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