Experimental study on flash pyrolysis of pulverized coals in Py-GC

Flash pyrolysis characteristics of four Chinese coals were studied in a Curie-pointed reactor and gas chromatography (Py-GC) combined system. The yield of volatile matter (VM) and evolution of gaseous VM components were measured. It is found that ≥ 50% of VM is released at the early stage (t ≤ 2 s) of flash pyrolysis. It needs ~10 s to totally devolatilize 1 mg coal in the Curie-point reactor with the sample wrapped in a ferromagnetic foil. The yields of gaseous VM component are in the order of H₂ > CH₄ > CO > CO₂ > C2(C₂H₆, C₂H₄) > C3 (C₃H₈, C₃H₆). The yield of VM increases as the pyrolysis temperature increases. Under the same pyrolysis condition, high VM content coals released more VM than the low VM content ones. Yields of H₂ and CH₄ increase greatly with the pyrolysis temperature. Yields of CO and CO₂ depend on both the content of oxygen in the coal and pyrolysis temperature. Amounts of C2 and C3 gases are relatively much less than the others, accounting for less than 5% in volume in the gaseous VM.