The Operation Principle of Carbon Fiber Sintering Furnace
Release time:
2025-06-26
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Abstract
Carbon Fiber Sintering Furnace is a key equipment used for the production of carbon fiber, which is mainly used to carbonize and graphitize pre-oxidized polyacrylonitrile (PAN) fibers or pitch-based fibers at high temperatures, ultimately resulting in high-performance carbon fibers.
1. Core working principle
Carbon Fiber Sintering Furnace by high temperature (usually 1000°C~3000°C) under the protection of inert gas (such as nitrogen, argon), so that the non-carbon elements in the fiber (such as hydrogen, oxygen, nitrogen, etc.) in the form of gas to escape, and at the same time to promote the rearrangement of the carbon atoms to form a highly ordered graphite microcrystalline structure. It is specifically divided into two stages:
Carbonisation stage (1000°C~1500°C):
Non-carbon elements (e.g. H₂O, CO₂, NH₃, etc.) in the pre-oxidised fiber are pyrolytically volatilised, and the remaining carbon atoms form a chaotic graphite structure.
Graphitization stage (2500°C~3000°C, optional):
Further increase the temperature to make the carbon atoms more regular and enhance the modulus and electrical conductivity of the fiber (for high modulus carbon fibers).
2. Key workflows
Feeding and sealing
The fibers are fed into the furnace chamber through a sealed feed opening to avoid air ingress (oxygen causes oxidative ablation of the fibers).
The furnace body is double water-cooled to ensure safe external temperature.
Inert gas protection
A continuous supply of high-purity nitrogen (N₂) or argon (Ar) maintains an oxygen-free environment in the furnace (oxygen content <10 ppm).
The gas flow and pressure must be precisely controlled to prevent the penetration of outside air.
Segmented heating
Low-temperature zone (300°C~800°C): further removal of residual volatiles.
Medium temperature zone (800°C~1500°C): carbonisation main reaction zone, non-carbon elements cracking.
High temperature zone (1500°C~3000°C, graphitising furnace): graphite heaters or induction heating are used to promote the growth of graphite microcrystals.
Temperature control
PID algorithms or multi-stage temperature control systems are used to ensure temperature uniformity (within ±5°C).
For high temperatures Graphite heaters (3000°C), tungsten/molybdenum heaters (2000°C) or induction heating (contactless heating) are commonly used.
Discharge and Cooling
The fibers are cooled down slowly through the cooling zone to avoid sudden cooling leading to structural defects.
The outlet is protected by an inert gas until the fibers have cooled completely.
3. Core technology and equipment features
Heating method:
Resistance heating (commonly used graphite heaters), induction heating (high-frequency electromagnetic field), microwave heating (high efficiency but high cost).
Furnace material:
Graphite felt/carboncarbon composite material (high temperature resistance, thermal shock resistance), ceramic fibre (heat insulation).
Gas system:
Gas purification device required (e.g., deoxygenation tower, drying tower).
Energy saving design:
Waste heat recovery system (e.g. preheat intake air), multi-layer thermal insulation structure.
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Zhuzhou Chi Carbon Automation Equipment Co., Ltd
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Email:13077017815@163.com
chitanauto@163.com
Adresse:
Room 201-2, 2nd Floor, Jixiang Complex Building, Liyu Industrial Park, Tianyuan District, Zhuzhou City, Hunan Province
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