Method for preparing general grade carbon fiber by using coal liquefaction residues

Abstract

The invention discloses a method for preparing general grade carbon fibers by using coal liquefaction residues, and relates to the technical field of preparation of general grade pitch-based carbon fibers. The preparation method comprises the following steps: mixing and purifying coal liquefaction residues and tetrahydrofuran, mixing an obtained coal liquefaction residue extract and a chlorinating agent in an inert atmosphere, heating and melting, chlorinating at a constant temperature of 120-260 DEG C, dechlorinating at a constant temperature of 320-370 DEG C, and cooling to room temperature after the reaction is completed to obtain an asphalt precursor; adjusting the softening point of the asphalt precursor to 220-260 DEG C, carrying out melt spinning to obtain asphalt fibers, and then carrying out pre-oxidation and carbonization treatment on the asphalt fibers to obtain the carbon fibers. The coal liquefaction residues are used as the raw material, the asphalt precursor is synthesized through a chlorination-dechlorination method, the preparation method is simple, the operation cost is low, no strong-corrosion raw material is adopted, and the strength performance of the prepared general-grade carbon fiber is remarkably superior to that of existing commercially available general-grade carbon fiber.

Description

technical field [0001] The invention relates to the technical field of preparation of general-purpose pitch-based carbon fibers, in particular to a method for preparing general-purpose carbon fibers from coal liquefaction residue. Background technique [0002] Coal direct liquefaction technology is a kind of clean coal technology, which can alleviate the current energy situation of lack of petroleum resources to a certain extent. A large amount of coal liquefaction residue will be produced in the process of direct coal liquefaction, accounting for about 30% of the total coal input. Coal liquefaction residue has high carbon content and high content of aromatic components, but high ash and sulfur limit the high value-added utilization of coal liquefaction residue. The efficient, reasonable and high value-added utilization of coal liquefaction residue is of great significance to the development and application of direct coal liquefaction technology. [0003] The preparation o...

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Problems solved by technology

The document "Preparation of general-purpose pitch-based carbon fiber from catalytic oil slurry [D]. Beijing: Beijing Institute of Petrochemical Technology, 2015. Li Peipei." discloses that the catalytic oil slurry is used as raw material, the raw material is pretreated by heat treatment, and the precursor is prepared by extraction method Pitch is used for spinning to make carbon fiber. This method has many preparation steps and the process is cumbersome, and it is difficult to be used in continuous actual industrial production.

The document "Kim B J, Eom Y, Kato O, et al. Preparation of carbon fibers with excellent mechanical properties from isotropic pitches [J]. Carbon, 2014, 77: 747-755." is based on naphtha cracked oil as raw material, using Isotropic pitch with good spinnability was synthesized by bromination-debromination method, and isotropic pitch-based carbon fiber with a tensile strength of 1500 MPa was prepared by spinning, but the elemental bromine used in this method was expensive and corrosive strong, has a certain degree of danger and has high requirements for the anti-corrosion performance of the equipment

[0004] The Chinese invention patent with the application number 202010468692.8 "A method for preparing general-purpose pitch-based carbon fibers from coal liquefaction residues" reports a method for preparing general-purpose carbon fibers from coal liquefaction residues. Suction filtration and oxidative polycondensation to obtain a pitch precursor with a softening point of 240-340°C, and then prepare carbon fibers through melt spinning, non-melting treatment, and carbonization processes. The preparation process of this technology is cumbersome and there are many operating steps

The Chinese invention patent "Preparation method of pitch carbon fiber" with application number CN200910019693.8 reports a preparation method of pitch carbon fiber composed of polycondensation, spinning, non-melting, carbonization, high-temperature graphitization, surface modification and other processes. This technology uses the polycondensation method to prepare spinning pitch, and a large amount of synthetic agents are added in the polycondensation process, the operation cost is high, and the mixing of organic matter is potentially dangerous

[0005] It can be seen from this that the current preparation method of pitch-based carbon fiber is mainly the thermal condensation polymerization method, which is not effective in regulating the properties and performance of carbon fiber, resulting in that the strength and performance of carbon fiber made from coal liquefaction residue are still relatively large. Room for improvement