Fate of polycyclic aromatic hydrocarbons during vitrification of incinerator ash in a coke bed furnace.
Fate of polycyclic aromatic hydrocarbons (PAHs) during the vitrification of fly ash and bottom ash from the municipal waste incinerator in a coke bed furnace was investigated. In this system, both coke and lime were added to enhance the melting reaction. The major PAH sources in this system were ash and coke, which respectively contributed 97% and 3% of PAHs in the input-mass. During vitrification process, low molecular PAHs (LM-PAH, 2-3-ring), median molecular PAHs (MM-PAH, 4-ring) and high molecular PAHs (HM-PAH, 5-7-ring) mass respectively accounted for >99%, >99% and 84% of the output-mass emitted as the stack flue gas; while those discharged from the slag were <1%, <1% and 16%, respectively. The O/I (output-mass/input-mass) ratio of LM-, MM- and HM-PAHs were 0.063, 0.002 and <0.001, respectively. The high distribution in flue gas and O/I ratio of LM-PAHs is reasonable since they are more easily evaporated, hence difficult to be removed by air pollution control devices. On the contrary, the HM-PAHs, having lower vapor pressure, primarily stays mainly in slag. Based on the 21 total PAH content in feeding ash and slag, the reduction efficiency of the coke bed furnace was >99.9%. To minimize the risk of secondary pollution, the efficiency of coke bed furnace should be improved to reduce the PAH emission into ambient air.
Kuo
Yi-Ming
YM
Department of Environmental Engineering, National Cheng Kung University, 1, University Road, Tainan 70101, Taiwan, ROC.
Lin
Ta-Chang
TC
Tsai
Perng-Jy
PJ
Lee
Wen-Jhy
WJ
Lin
Hsin-Yi
HY
D000393:Air Pollutants / Q000032:analysis*; D017610:Calcium Compounds / Q000737:chemistry; D003077:Coke; D004784:Environmental Monitoring; D017745:Incineration; D010087:Oxides / Q000737:chemistry; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D012037:Refuse Disposal; D014835:Volatilization
D000393:Air Pollutants; D017610:Calcium Compounds; D003077:Coke; D010087:Oxides; D011084:Polycyclic Aromatic Hydrocarbons; C016538:lime