Char- and Aerosol-associated Polycyclic Aromatic Compounds from Coal Pyrolysis: Relationship Between Particle Size and Surface Composition

Abstract

In order to investigate the relationship between solid size and polycyclic aromatic compound (PAC) amount and composition, we have pyrolyzed 45–53-μm particles of a high-volatility bituminous coal at 1100–1500 K in a laminar flow, drop-tube furnace. Aerodynamically separated in a cascade impactor, three size cuts of the solid products have been collected for determination of PAC and solid carbon mass yields. We have also examined differences in PAC composition of the three size cuts by employing a liquid chromatographic technique that separates PAC according to their number of fused aromatic rings. Soot yields are found to increase with increasing temperature; char and PAC yields decrease. Yields of the most volatile PAC decay particularly rapidly with increasing temperature. For all pyrolysis conditions investigated, > 90% of the PAC is associated with the soot (the smaller two size cuts), but the proportion associated with the larger particles grows as the total amount of PAC lessens. For all experiment...