Project: Coal-derived carbon fiber
School: University of Utah
Location: Salt Lake City
Principal Investigator: Eric G. Eddings
Researchers at the University of Utah’s Industrial Combustion and Gasification Research Facility hope to breathe new life into Utah’s rural coal-based communities by developing cost-effective ways to produce carbon fiber from coal.
American coal is primarily used to generate electric power. In contrast, petroleum has been developed into a range of products that include commodity chemicals, plastics, polyesters – and PAN-based carbon fiber. In fact, more than 90 percent of the world’s carbon fiber is derived from PAN. “Coal, in like manner, could be considered raw material for a number of different products,” says Eric G. Eddings, a professor and associate dean for research in the College of Engineering at the University of Utah. “It’s just that we haven’t historically done that.”
To help develop carbon fiber from coal, Eddings and his team have embarked on a three-year, $1.6 million research project that includes a $790,000 POWER grant from the U.S. Economic Development Agency (EDA) and collaboration with the University of Kentucky and the Utah Advanced Materials Manufacturing Initiative (UAMMI).
Researchers will collect samples from Utah coal mines and create tar samples that can be further processed to form “pitch.” This pitch will be spun into carbon fiber at the University of Kentucky Center for Applied Energy Research, which has one of the country’s few production lines for smaller-scale spinning of experimental carbon fibers, according to Eddings. The team hopes to identify cost-reducing approaches to carbon fiber production. These may include identifying coals or processes with higher pitch yields, reducing processing time and developing processes to create high value co-products that can be sold to offset costs. Or, as Eddings sums it up, “Anything to save money.”
For now, the Utah team is processing the coal using pyrolysis. The coal is first ground into a fine dust and then heated with a simple laboratory reactor as an auger pushes it through a furnace. This decomposes the coal’s large hydrocarbon molecules into smaller gaseous molecules, or vapors. The vapors are then cooled, and the heavier molecules used in the production of pitch condense first, as tar. This tar is then distilled to separate the pitch, which can then be upgraded to mesophase pitch via heat treatment under inert conditions. In contrast to isotropic pitch, Eddings says, “Mesophase pitch has liquid crystals in it that help create highly graphitized and ordered carbon fiber that has much, much better properties.”