Heat treatment of medium-temperature Sasol–Lurgi gasifier coal-tar pitch for polymerizing to higher value products

Two coal-derived pitch samples, one a medium temperature pitch from a Sasol–Lurgi gasifier and the other from a high temperature coking process, have been heat treated to induce polymerization, both separately and as a mixture of pitches (co-pyrolysis). The initial pitch samples and the heat-treated samples have been examined by size exclusion chromatography (SEC) in 1-methyl-2-pyrrolidinone (NMP), by UV-fluorescence spectroscopy (UV-F), by solid state 13C NMR; elemental analyses of the initial pitch samples have been carried out. The Sasol–Lurgi pitch showed larger apparent sizes, more alkyl and carbonyl functions, and smaller polycyclic aromatic hydrocarbon (PAH) groups than the high temperature pitch. Co-pyrolysis of the two pitches indicated that polymerized product from the Sasol–Lurgi pitch can be used as an extender for high-temperature binder pitch.