Reduction of polycyclic aromatic hydrocarbons (PAHs) emission from household coal combustion using ferroferric oxide as a coal burning additive

Abstract

Household coal combustion is identified to be the second largest emission source of polycyclic aromatic hydrocarbons (PAHs) in China. In this study, ferroferric oxide (Fe3O4) was used as a coal burning additive to reduce PAHs emission from coal combustion in a household coal stove. The results showed that Fe3O4 participated in the coal combustion process. The addition of Fe3O4 reduced the release of PAHs during the coal combustion process, and could improve the residence capacity of ash residue to these PAHs. Toxic equivalent quantity (TEQ) of PAHs in flue gas from combustion of coal mixed with Fe3O4 was less than that from the raw coal combustion. For a typical combustion temperature of 850 °C, the TEQ of PAHs for the mixture of coal and 2.0 wt% Fe3O4 decreased 21.98% compared to that for the raw coal. The abundant active surface oxygen species originated from the phase transformation of iron oxides probably accelerated the cracking of PAHs, and hence led to the reduction of PAH emissions and their TEQ. The study could help to develop new technology for reduction of PAHs emission from household coal combustion.