A kind of preparation method of high mesophase content mesophase pitch

Abstract

The invention provides a preparation method of mesophase pitch with high mesophase content. The preparation method comprises the following steps of: preprocessing naphthene-based atmospheric pressure residual oil, taking cut fraction obtained at the temperature of 400-540 DEG C as a reaction raw material, mixing a co-carbonization additive with the raw material in mass fraction of 5-10%, carrying out thermostatic reaction for 4-6 hours at the temperature of 260-290 DEG C, then increasing a reaction pressure to 1-5MPa, warming to 330-360 DEG C, and then continuously carrying out the thermostatic reaction for 4-6 hours, thus high-quality mesophase pitch is obtained. The preparation method of the mesophase pitch with high mesophase content has the advantages that a process is simple and practicable and requirement on properties of the raw material is low; and the obtained mesophase pitch is high in yield, good in optical structure and good in spinnability, and mesophase content is more than 95%, so that the mesophase pitch is a good precursor for producing a high-quality carbon material.

Description

technical field [0001] The invention relates to a method for preparing intermediate pitch with high intermediate phase content. Background technique [0002] Mesophase pitch, referred to as MP, is a nematic liquid crystal substance composed of a variety of flat disk-shaped condensed ring aromatic hydrocarbons with an average relative molecular mass of about 2000, also known as liquid crystal phase pitch. It is obtained from coal, petroleum asphalt, pure aromatics, heavy oil, etc. through thermal condensation polymerization. Mesophase pitch has the characteristics of liquid crystals, has both liquid form and optical anisotropy characteristics, and its low preparation cost, high oxidation activity, and high carbon purity are excellent precursors for the preparation of high-performance carbon materials. Mesophase pitch can be used as raw material to prepare carbon fiber, needle coke, mesophase pitch-based carbon foam, mesophase pitch-based electrode material, mesophase pitch-b...

AI Technical Summary

Problems solved by technology

The one-step thermal polycondensation method has too high requirements on the properties of raw materials, and the obtained mesophase pitch has a higher softening point; the new mesophase method is more complicated, and the yield of mesophase pitch is low; the catalyst commonly used in the catalytic polycondensation method is AlCl 3 、HF / BF 3 , where AlCl 3 After the reaction, it cannot be separated from the reaction system, while HF / BF 3 The corrosion of the reactor is relatively large; the hydrogenation process of the potential mesophase method is relatively difficult, the cost is high, and the process is complicated

The heat treatment temperature of the above methods is generally higher than 400 °C, which is prone to problems such as excessive polymerization degree in the reaction, high softening point of the product, and waste of energy.

[0004] At present, the cost of producing high-quality mesophase pitch by conventional methods is relatively high, and the processing process is complicated. The yield of mesophase pitch obtained is low, the softening point is high (generally greater than 300°C), and the spinning performance is not good, so it cannot be used to produce high-quality carbon materials

Japanese patent JP114221 / 86 hydrogenates the raw materials and uses solvent extraction technology. Although the obtained mesophase pitch has a high content of mesophase and a low softening point, the residual solvent will affect the carbon fiber made from it. The quality of this method is relatively complicated, and the cost of the obtained mesophase pitch is relatively high

Chinese patent CN1015255543 uses refined naphthalene as a raw material and adds hydrogen fluoride and boron trifluoride as a catalyst to prepare mesophase pitch. However, this method has strict requirements on raw materials for refined naphthalene, and the reaction pressure is too high. , and the catalysts hydrogen fluoride and boron trifluoride are highly acidic, causing corrosion to equipment