Continuous carbon fiber recovering method and continuous carbon fiber recovering device

Abstract

The invention discloses a continuous carbon fiber recovering method comprising the following steps: step S10, heating the lower end of a thermal cracking hearth by heated air or high temperature fluegas generated from cracking reaction, and preheating a first preheating tube and a second preheating tube; step S20, blowing a waste carbon fiber reinforced resin-based composite material into the thermal cracking hearth by the first preheating tube, and at the same time, blowing solid superacid particles into the thermal cracking hearth via the second preheating tube; and step S30, merging the waste carbon fiber reinforced resin-based composite material and the solid superacid particles in the thermal cracking hearth and carrying out contact reaction, separating generated organic gas with carbon fibers in a cyclone separator to recover the carbon fibers, allowing the organic gas to enter a high temperature burner through an induced draft fan, and burning. A solid superacid is used for replacing fluidized sand particles, and the feeding and preheating methods are improved, so that the resin matrix is uniformly heated and catalytically decomposed, and thus the carbon fiber resources arerecovered and reused.

Description

technical field [0001] The invention relates to the technical field of carbon fiber recovery from waste carbon fiber reinforced composite materials, in particular to a continuous carbon fiber recovery method and a continuous carbon fiber recovery device used in the method. Background technique [0002] Carbon fiber is a new type of high-strength, high-modulus fiber material with a carbon content of more than 95%. Carbon fiber is composited with a matrix such as resin, metal, and ceramics to form a structural material called Carbon Fiber Reinforced Polymer (Carbon Fiber Reinforced Polymer, CFRP). [0003] Carbon fiber reinforced composite materials have excellent properties such as light weight, high strength, good heat resistance and corrosion resistance, and are widely used in aerospace, sports equipment, medical equipment, transportation, electronic appliances, wind power industry and other fields. An irreplaceable important strategic material. With the rapid expansion o...

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Problems solved by technology

The pyrolysis method is to place waste carbon fiber reinforced composite materials under the condition of no oxygen (CN 103665427 A, CN 107345000 A) or low oxygen (CN103665430 A, CN 107417963 A) and utilize high-temperature thermal decomposition method. The process operation is simple, but the recovery can be The carbon fiber surface of the waste carbon fiber is easy to accumulate carbon, so that the carbon fiber is distributed in a block shape, which seriously affects the reuse performance; utilize a layer of solid super acid SO42- / TiO2 powder (CN 106957451 A) on the surface of the waste carbon fiber resin matrix composite material or the main component is Zinc chloride powder (CN 106807425 A) and other catalysts are placed in a pyrolysis furnace to fully react at high temperature to obtain carbon fibers with high mechanical property retention and recovery. However, after the pyrolysis reaction, the catalyst is difficult to recycle. Or the recycling process is complex, resulting in waste of resources and increased recycling costs. At the same time, the method of laying powder catalyst on the surface is more suitable for batch pyrolysis devices, and the production is discontinuous

[0006] And traditional fluidized bed recovery technology ((Plastics, Rubber and Composites, 2002,31 (6): 278-282; Applied Surface Science, 2008, 254: 2588-2593; CN 104513406 A) utilizes air as fluidizing gas to make The carbon fiber composite material is suspended in the bed, and the matrix is ​​thermally cracked to obtain recycled carbon fibers with a clean surface, no carbon deposits, and less damage and damage. This technology is widely accepted and recognized, and its advantage is that it can handle heavily polluted waste or mixed waste. , paint, foam core, thermoplastic resin and metal have no effect on the recycling process, the organic components will be decomposed into gas, the metal will fall on the sand on the gas distribution plate, the recycling process can achieve continuous feeding and discharging, resin The energy of matrix oxidation can be used in the recovery process, but since the reaction also needs to be carried out under high temperature conditions (450-550°C), and each composite waste needs to be reacted for 10-20 minutes on average, the energy consumption is large, the time is long, and the Equipment consumption is large, and high-temperature oxidation and long time are likely to cause damage to the mechanical properties of carbon fibers, which restricts the industrialization process of fluidized bed recovery of carbon fibers; although oxide semiconductors have been used to replace fluidized bed sand beds (CN 106750505 A) , through thermal activation, the oxide semiconductor generates holes, and the formed holes have excellent oxidative decomposition ability, and at the same time, the thermal decomposition temperature is reduced, but the oxide semiconductor is easy to react with the carbon deposition generated in the reaction process, resulting in deactivation , it is necessary to shut down the furnace to replace new oxide semiconductors, resulting in discontinuous production and low recovery efficiency

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