PAH emission from the steel and iron industries

PAH (Polycyclic Aromatic Hydrocarbon) emission from ten steel and iron industrial plants in southern Taiwan were investigated. The steel and iron industries were classified into 3 categories: Group I (using coal as fuel), Group II (using heavy oil as fuel) and Group III (electric are furnace). The average mass distribution of total-PAHs in the whole sampling train was predominately in the gas phase (88.6%) due to high temperature in stack flue gas, whereas there were 6.79% in the particulate phase, 3.05% in the cooling water and 1.82% in the pipe residual. The total-PAHs emission factors for coal, heavy oil and electrical are furnace were 4340 mu g/kg-coal, 6050 mu g/L-oil, 2670 mu g/kWh, respectively. The baghouse was found to be have a higher PAH removal efficiency than that of cyclone. This result indicated that the particle size of fly ash removed from baghouse is smaller than that from cyclone, and the smaller-size particulate has more specific surface area and therefore, allows more PAH, to be adsorbed onto it.