PAH emission from the industrial boilers

Polycyclic aromatic hydrocarbons (PAHs) emitted from 25 industrial boilers were investigated. The fuels used for these 25 boilers included 21 heavy oil, two diesel, a co-combustion of heavy oil and natural gas (HO + NG) and a co-combustion of coke oven gas and blast furnace gas (COG + BFG) boilers. PAM samples from the stack flue gas (gas and particle phases) of these 25 boilers were collected by using a PAH stack sampling system. Twenty one individual PAHs were analyzed primarily by a gas chromatography/mass spectrometer (GC/MS). Total-PAM concentration in the flue gas of 83 measured data for these 25 boiler stacks ranged between 29.0 and 4250 mu g/m(3) and averaged 488 mu g/m(3). The average of PAH-homologue mass (F%) counted for the total-PAH mass was 54.7%, 9.47% and 15.3% for the 2-ring, 3-ring and 4-ring PAHs, respectively. The PAHs in the stack flue gas were dominant in the lower molecular weight PAHs. The emission factors (EFs) of total-PAHs were 13 300, 2920, 2880 and 208 mu g/kg-fuel for the heavy oil, diesel, HO + NG and COG + BFG fueled-boiler, respectively. Nap was the most predominant PAH occurring in the stack flue gas. In addition, the EF of 21 individual PAHs in heavy-oil boiler were almost the highest among the four various fueled-boilers except for those of FL and BkF in the diesel boiler. Furthermore, the EF of total-PAHs or BaP for heavy oil were both one order of magnitude higher than that for the diesel-fueled boiler. (C) 1999 Elsevier Science B.V. All rights reserved.