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System to Continuously Produce Carbon Fiber via Microwave-Assisted Plasma Processing

Oak Ridge National Laboratory

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PDF Document Publication11-G00246_ID1518 (2).pdf (889 KB)

Technology Marketing SummaryUsing a microwave-assisted plasma (MAP) system developed at ORNL, carbon fibers with specific mechanical properties can be produced on a continuous or semi-continuous basis more efficiently and less expensively than conventional methods. This invention can contribute towards widespread use of carbon fiberbased composites by the consumer industry as an alternative to lower-strength, heavier conventional structure materials such as steel.DescriptionCurrent carbon fiber production methods are challenged by the high-cost of carbon pre-cursors, the expensive energy and equipment, and the cost associated with a limited production rate. Carbon and graphite fibers are conventionally produced through the controlled pyrolysis of fibrous organic carbon precursors such as polyacrylonitrile (PAN), mesophase pitch (petroleum or coal tar), rayon, or other polymeric-based precursors in a lengthy process. The three process stages of carbonization, graphitization, and surface treatment represent much of the cost associated the overall carbon fiber manufacturing process due to their time, power, and maintenance requirements.BenefitsThe MAP system simplifies carbon fiber production by replacing the carbonization, graphitization, and surface treatment process steps with a signal MAP processing step. The combined use of microwave and plasma energy allows the system to operate at a low thermal inertia (low mass) in less time and with less energy than conventional processes. Another major benefit is that the off-gases produced during the carbonization process supplement the plasma reaction and drive carbonization, thus reducing the amount of volatile gases in the effluent gas stream and the amount of incineration required. 

•Lower production cost for carbon fibers with acceptable automotive-quality mechanical properties
•Less incineration of effluents is required, including greenhouse gases produced during the process
•Complete processing of fibers from a fully oxidized precursor all the way to surfacetreated carbon fiber

Applications and Industries•Industries requiring lightweight, highstrength carbon fiber material
•Automotive industry
•Energy producing companies
Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Patent 7,824,495
System to continuously produce carbon fiber via microwave assisted plasma processing
A system to continuously produce fully carbonized or graphitized carbon fibers using microwave-assisted plasma (MAP) processing comprises an elongated chamber in which a microwave plasma is excited in a selected gas atmosphere. Fiber is drawn continuously through the chamber, entering and exiting through openings designed to minimize in-leakage of air. There is a gradient of microwave power within the chamber with generally higher power near where the fiber exits and lower power near where the fiber enters. Polyacrylonitrile (PAN), pitch, or any other suitable organic/polymeric precursor fibers can be used as a feedstock for the inventive system. Oxidized or partially oxidized PAN or pitch or other polymeric fiber precursors are run continuously through a MAP reactor in an inert, non-oxidizing atmosphere to heat the fibers, drive off the unwanted elements such as oxygen, nitrogen, and hydrogen, and produce carbon or graphite fibers faster than conventionally produced carbon fibers.
Oak Ridge National Laboratory 11/02/2010
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
UT-B ID 200501518PrototypeAvailable11/21/201110/25/2011

Contact ORNL About This Technology

To: Alexander G. DeTrana<>