Some Aspects of the Mechanism of Formation of Smoke from the Combustion of Wood

This paper is concerned with an investigation of the formation of soot from the combustion of some of the primary pyrolysis products formed during pine wood combustion. Comparisons are made between the combustion products of model compounds, furfural for cellulose and eugenol and anisole to represent lignin (and n-decane for comparison) with the smoke emissions from the previously studied combustion of pine wood. These compounds were burned in a diffusion flame burner, and the appearance and composition of the resulting particulate and the adsorbed polynuclear aromatic hydrocarbon (PAH) precursors were studied by transmission electron microscopy (TEM), mass spectrometry and pyrolysis gas chromatography mass spectrometry (Py-GC-MS). The reactions leading to soot formation were modeled. It was concluded that wood soot formation proceeded via pyrolytic breakdown followed by a mechanism based on HACA (H-abstraction–C2H2-addition) reactions with the participation of cyclopentadienyl intermediates, while eugenol soot originated predominantly through the CPDyl route. The formation of furfural soot is mainly via HACA.