Emissions of Polycyclic Aromatic Hydrocarbons from Batch Hot Mix Asphalt Plants

Abstract

This study was set out to assess the characteristics of polycyclic aromatic hydrocarbon (PAH) emissions from batch hot mix asphalt (HMA) plants and PAH removal efficiencies associated with their installed air pollution control devices. Field samplings were conducted on six randomly selected batch HMA plants. For each selected plant, stack flue gas samples were collected from both stacks of the batch mixer (n = 5) and the preheating boiler (n = 5), respectively. PAH samples were also collected from the field to assess PAHs that were directly emitted from the discharging chute (n = 3). To assess PAH removal efficiencies of the installed air pollution control devices, PAH contents in both cyclone fly ash (n=3) and bag filter fly ash (n = 3) were analyzed. Results show that the total PAH concentration (mean; RSD) in the stack flue gas of the batch mixer (354 microg/Nm3; 78.5%) was higher than that emitted from the discharging chute (107 microg/Nm3; 70.1%) and that in the stack flue gas of the preheating boiler (83.7 microg/Nm3; 77.6%). But the total BaPeq concentration of that emitted from the discharging chute (0.950 microg/Nm3; 84.4%) was higher than contained in the stack flue gas of the batch mixer (0.629 microg/Nm3; 86.8%) and the stack flue gas of the preheating boiler (= 0.112 microg/Nm3; 80.3%). The mean total PAH emission factor for all selected batch mix plants (= 139 mg/ton x product) was much higher than that reported by U.S. EPA for the drum mix asphalt plant (range = 11.8-79.0 mg/ton x product). We found the overall removal efficiency of the installed air pollution control devices (i.e., cyclone + bag filter) on total PAHs and total BaPeq were 22.1% and 93.7%, respectively. This implies that the installed air pollution control devices, although they have a very limited effect on the removal of total PAHs, do significantly reduce the carcinogenic potencies associated with PAH emissions from batch HMA plants.

Emission of polycyclic aromatic hydrocarbons (PAHs) from the liquid injection incineration of petrochemical industrial wastewater

“…Contrary to previous finding that the PAH emission from the combustion process was consistently dominated by LM-PAHs [10,11], LM-PAHs (436 g Nm −3 ) and HMPAHs (444 g Nm −3 ) showed similar average concentration in this study (Table 2). Among the HM-PAH compounds, IND (130 g Nm −3 ) and DBA (178 g Nm −3 ) showed especially high concentrations.…”

“…(APCDs) [4]. A number of studies examined the PAH emission from combusting various types of waste and fuels [5][6][7][8][9][10][11][12][13][14][15][16][17]. The PAH emission from the medical waste incinerators with higher plastic content were much greater than that from municipal waste incinerators [11,15].…”

Modeling of Polycyclic Aromatic Hydrocarbons stack emissions from a hot mix asphalt plant for gate-to-gate Life Cycle Inventory

“…More generally, the chemical composition of bitumen may have some significant effects. However, the chemical composition of the PAHs stack emissions studied is surprisingly very similar to that obtained in a previous studies (Lee et al, 2004;Ventura et al, 2007). Although this similarity tends to prove the negligible influence of bitumen types, the relevance of the model must be confirm with additional analyses before excluding this factor.…”

“…Obtained measures for each Test and compound, including PAHs, are given in Table 3. (Lee et al, 2004;Ventura et al, 2007). The total PAH mass flow increases with both the production rate and the asphalt temperature but is, above all, a function of its two major compounds.…”

“…However, a survey of the literature (Santero et al, 2011a) reveals that very few LCI data are currently available regarding Polycyclic Aromatic Hydrocarbons (PAH) emitted by asphalt plants Lee et al, 2004;US-EPA, 2000a, 2004Ventura et al, 2007Ventura et al, , 2004.…”