Soot formation during coal pyrolysis

Soot can be found in almost all combustion and pyrolysis systems. In a coal system, the impact of soot on coal combustion can be identified in two ways. First, soot particles suspended in the combustion flame significantly enhance radiative heat transfer near the burner due to their large surface area, small size and spectrally continuous radiation characteristics [1]. Second, part of the nitrogen released from coal during devolatilization will be reincorporated into soot, which complicates nitrogen transformations and NOx production. The study of the chemical structure of soot is also important for many environmental and health reasons. Soot, formed by condensation of polyaromatic hydrocarbons (PAH), poses a health hazard, since many PAH produced in pyrolysis or combustion processes are carcinogenic and mutagenic materials [2]. Soot has also been found in the unburned carbon in flyash [3].