A pretreatment method of raw material oil for the preparation of spinnable mesophase pitch and high-performance pitch-based carbon fiber

Abstract

The invention discloses a method for pretreatment of raw material oil for preparing spinnable mesophase pitch and high-performance pitch-based carbon fiber. In this method, one or more heavy fractions above 300°C of aromatic-rich heavy oil, catalytic cracking oil slurry, coal tar or ethylene tar are used as raw materials to carry out an ultrasonic-assisted filtration deashing coupling enhanced extraction process, and further pass Gel permeation chromatography technology realizes the flexible adjustment of the structure and composition of refined raw materials, and obtains high-quality aromatic-rich raw material oil with narrow molecular weight distribution. The aromatic content is 70wt% to 90wt%, mainly composed of 3 to 5 rings rich in short side chain aromatic compounds , while the number-average molecular weight distribution of 80% of the raw material oil molecules is between 300-500; the softening point of the mesophase pitch prepared by the thermal condensation reaction of the refined raw materials obtained from the above pretreatment is 260°C-310°C, and the content of the mesophase ≥95%, it is a kind of mesophase pitch with good spinning performance.

Description

technical field [0001] The invention relates to a pretreatment method for preparing raw material oil for spinning mesophase pitch and high-performance pitch-based carbon fiber, and belongs to the field of petroleum deep processing technology and carbonaceous mesophase material research. Background technique [0002] With the consumption of petroleum resources, the development of petroleum in the world shows the characteristics of deepening the degree of inferiority and increasing the output of heavy oil. The development and utilization of petroleum heavy oil and secondary residual oil have become an important part of petrochemistry. Moreover, heavy oil accounts for a large proportion of my country's imported crude oil. It is of great practical and economic significance to rationally and effectively utilize a large amount of heavy residual oil produced in the process of crude oil processing to realize deep processing of residual oil and increase added value. [0003] Mesopha...

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Problems solved by technology

This method removes heavy components with higher molecular weight and light components with lower molecular weight in the feedstock oil, and the molecular weight distribution of the feedstock oil is concentrated. However, this patent only uses a single process to regulate the properties of the feedstock oil. Some other components of the feedstock oil Properties such as S, N heteroatom content, and the removal of catalyst solid powder are difficult to balance; patent CN111019700A discloses a preparation method of mesophase pitch precursor, and coal tar is extracted with a mixture of petroleum ether and acetone to obtain an organic solvent mixture, and then The mixture is filtered under reduced pressure, followed by distillation under reduced pressure, and the fraction in the range of 280-320 °C is taken to obtain a mesophase pitch precursor mainly containing four-ring and five-ring aromatics

This method also has a single pretreatment process, there is no step of removing heteroatoms (S, N, etc.), and the saturation rate of aromatics and olefins is not controlled.

Due to the complex structure and composition of heavy oil, the hydroprocessing efficiency is low under the condition of no catalyst, and it is difficult to effectively remove the sulfur and nitrogen heteroatoms in the raw oil. At the same time, the hydrogenation saturation reaction of the aromatic part will also occur, reducing the aromaticity of the raw oil, and It is difficult to obtain suitable spinnable mesophase pitch as a raw material

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