Carbon Fiber Production Heating Modules

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Solution Overview

Problem

Conventional carbon fiber production methods are inefficient at high temperatures, leading to increased energy costs and production time, making high-modulus carbon fibers non-competitive with other lightweight materials, especially in aerospace and automotive applications.

Innovation Solution

A multi-module system for carbon fiber production that combines electrical resistance heating, microwave plasma heating, and laser heating to achieve faster and more efficient carbonization, using conductive particles like carbon nanotubes to enhance electrical conductivity and allow for direct thermal energy transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional carbonization furnaces are used to produce high-modulus carbon fibers at high temperatures, then the tensile modulus of elasticity increases, but the energy costs and production time increase significantly

Engineering Contradiction:
Improvetensile modulus of elasticityVSAvoidenergy costs
Core Design Contradiction:
StrengthVSUse of energy by moving object

Solution Approach 1:

The patent replaces conventional thermal convection heating with direct electrical resistance heating and microwave heating methods. This substitution allows for more efficient energy transfer directly to the fiber material, reducing the overall energy requirements while achieving the same high temperatures needed for high-modulus carbon fiber production.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements multi-stage temperature control with different heating rates for different production stages. By optimizing temperature parameters and heating rates at each stage (pre-oxidation, carbonization, graphitization), the process achieves high tensile modulus while reducing total energy consumption and production time.

Inventive Principle:
Principle #35Parameter changes

2Strength

If conventional carbonization furnaces are used to produce high-modulus carbon fibers at high temperatures, then the tensile modulus of elasticity increases, but the production time increases

Engineering Contradiction:
Improvetensile modulus of elasticityVSAvoidproduction time
Core Design Contradiction:
StrengthVSDuration of action of moving object

Solution Approach 1:

The patent replaces slow thermal convection heating with rapid electrical resistance heating and microwave heating. This substitution enables much faster heating rates while maintaining controlled temperature profiles, significantly reducing the time required to achieve high-modulus carbon fiber properties.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements continuous processing with uninterrupted heating and processing stages. The multi-module system allows fibers to move continuously through pre-oxidation, carbonization, and graphitization stages without interruption, maximizing production efficiency while maintaining high tensile modulus.

Inventive Principle:
Principle #20Continuity of useful action

3Use of energy by moving object

If direct thermal energy transfer methods are used to increase heating rates, then energy efficiency improves, but the electrical conductivity requirement increases

Engineering Contradiction:
Improveenergy efficiencyVSAvoidelectrical conductivity requirement
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent divides the heating process into distinct stages with different heating methods. Electrical resistance heating is applied only when fibers have sufficient conductivity (after pre-oxidation), while microwave heating and conventional heating are used for stages where conductivity is insufficient. This segmentation allows efficient direct heating without requiring high conductivity throughout the entire process.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses microwave radiation as an intermediary heating method that does not require electrical conductivity in the fiber material. Microwaves can heat the fibers directly through dielectric heating, bridging the gap between stages where electrical resistance heating is not yet feasible and stages where high efficiency is required.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach reduces energy requirements and production time, enabling the production of carbon fibers with specific mechanical and thermal properties, improving their competitiveness and matching them better to product requirements.

Implementation Method 1

at least one module for electrical resistance heating of the fiber(s)

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

at least one further module for heating the fiber(s) by means of a plasma generated with microwaves

Methodology Applied
Scientific EffectMicrowave plasma: Plasma

Implementation Method 3

heating the fiber(s) by means of a plasma generated with microwaves

Methodology Applied
Scientific EffectMicrowave radiation: Microwave Radiation

Implementation Method 4

at least one further module for heating the fiber(s) by means of a plasma directed at the fiber(s) formed with a defocused laser beam

Methodology Applied
Scientific EffectLaser heating: Laser

Data Source

PatentEP3371350B1Apparatus for producing carbon fibers
Publication Date: 2020.04.15 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3371350B1 patent drawingFigure 1
  • EP3371350B1 patent drawingFigure 2
  • EP3371350B1 patent drawingFigure 3

AI summary

The invention relates to a facility for producing carbon fibres, in which at least one fibre made of a polymer material or a textile fabric made of polymer fibres is guided through a plurality of modules in the stabilised form as a precursor. The facility is provided with at least one module for the electrical resistance heating of the fibre(s), and at least one other module for heating the fibre(s) or the textile fabric by means of a microwave-generated plasma and/or for heating the fibre(s) by means of a defocussed laser beam aimed at the fibre(s).