THERMAL-DECOMPOSITION OF 2 COAL MODEL COMPOUNDS - PYRIDINE AND 2-PICOLINE - KINETICS AND PRODUCT DISTRIBUTIONS

The thermal decomposition of two coal model compounds, pyridine and 2- picoline, has been studied in a completely stirred fused-silica reacto r over the temperature range 1060-1240 K at pressures between 8.0 and 13.3 kPa and at reactor residence times between 1 and 5 s. Profiles of major products and kinetics of thermal decomposition of both compound s are given and a detailed investigation by GC/MS of the minor product s of decomposition has been made. Profiles of pyridine and its major p roducts of decomposition can be satisfactorily modelled by a homogenou s gas phase kinetic model. The rate of decomposition of 2-picoline was faster than predicted by a homogenous gas phase mechanism and the dec omposition would appear to be surface-assisted in the silica reactor. Both compounds were found to be useful models for the evolution of fue l-bound nitrogen from decomposition of coals. 2-Picoline, a nitrogen h eteroaromatic analogue of toluene, was found, like its hydrocarbon ana logue, to have a high propensity for sooting. The presence of the nitr ogen atom in the condensed ring products of 2-picoline was found to be a useful chemical marker for unravelling the complex condensation che mistry leading to the formation of soot.