The Emission Characteristic of PAHs during Coal Combustion in a Fluidized Bed Combustor

The emission characteristic of polycyclic aromatic hydrocarbons during coal combustion was studied in a fluidized bed combustor. The reaction temperature range was 750-850 degrees C and oxygen concentration studied was 3-12%. The experimental results demonstrated that the maximum amount of polycyclic aromatic hydrocarbons in flue gas occurred at 800 degrees C; above this temperature, polycyclic aromatic hydrocarbons concentration was decreased with the temperature increase. Contrary to temperature, the high oxygen content has a positive effect on suppressing the formation of polycyclic aromatic hydrocarbons. The amount of total polycyclic aromatic hydrocarbons reduced from 0.115 to 0.032 g/L as the oxygen content rose from 3 to 12%. Moreover, it was also found that the total toxic equivalent quantity of polycyclic aromatic hydrocarbons was dominated by the five-ring's polycyclic aromatic hydrocarbons, especially the Benzo (a) pyrene, Benzo (b) fluoranthene, and Benzo (k) fluoranthene.