Waste coal to high modulus carbon fiber

High modulus carbon fibers were successfully produced from mesophase pitch derived from waste coal extract, a direct liquefaction product stemming from Springfield coal thickener underflow and fluid catalytic cracking decant oil. For the process overall, 75% more carbon fiber mass was produced from the waste coal extract precursor liquid compared to decant oil alone. Melt spinning stability and extensibility were lower for mesophase pitch derived from the waste coal extract, potentially stemming from higher softening point temperature, isotropic content, and greater mass loss to vapor during melt spinning. Green fibers spun from the waste coal extract-derived mesophase pitch were more prone to void defects due to volatilization, primarily from the release of gaseous pyrolysis products at its elevated spinning temperature. The waste coal-derived carbon fibers exhibited good mechanical properties with an average modulus of 562 GPa and 1.22 GPa tensile strength. Compared to carbon fibers produced from decant oil alone, waste coal-derived carbon fibers showed a lack of splitting defects that contributed to a higher tensile strength but possessed a lower tensile modulus, crystallinity, and preferred crystalline alignment. These results demonstrate the potential for a value-added carbon fiber product from waste coal, which historically has had no market and remains an environmental hazard.