Removal characteristics of PCDD/Fs by the dual bag filter system of a fly ash treatment plant

PBDES are used as the flame retardants and have adverse effects on human health. Electric arc furnaces (EAF) are one of major emission source of PBDEs. The PBDE contents in the fly ashes of an EAF (29.3 ng/g) examined in this study were one to three orders higher than those in environmental soils. EAF fly ash treatment plants are established to resolve the disposal of this material, and also to recover the remaining iron or zinc from it. However, very little is known about the fate of PBDEs in EAF fly ash treatment plants. The EAF fly ash treatment plant investigated in this work can be divided into three sub-systems, including a pelletizer, reducing furnace and submerged arc furnace (SAF). The fly ash generated from the pelletizer process exhibited the highest PBDE content (7.69 ng/g), and contributed about 91% of the total PBDE inputs (4.40 g/day). The total PBDE concentrations in the stack flue gases of the pelletizer, reducing furnace and SAF were 24.5, 2.88 and 4.71 ng/Nm 3 , respectively. The high PBDE concentrations of the pelletizer resulted from not only the thermal desorption of lighter brominated congeners, but also fugitive particles of EAF fly ashes. Together, the three stacks accounted for 40.8% of the total PBDE outputs, revealing that the air pollution control devices deployed in the current study were not very effective with regard to removing PBDEs from the flue gas. The PBDE output/input ratio of the EAF fly ash treatment plant was 0.0378, and thus most PBDEs introduced into the system were decomposed. The EAF fly ash treatment plant examined in this work is thus a reliable facility with regard to the disposal of this material.

Section: Inputs and Outputs Of Pbdes In The Eaf Fly Ash Treatment Plantmentioning

confidence: 68%

Section: Inputs and Outputs Of Pbdes In The Eaf Fly Ash Treatment Plantmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Distribution of Polybrominated Diphenyl Ethers (PBDEs) in a Fly Ash Treatment Plant

Liao

Kennedy

et al. 2012

“…Several novel studies on the use of dual bag filters for air pollutant control only used ACI in the second bag filter (Kim et al, 2007, andLin et al, 2008). In this study, in order to reduce the loading of AC, the bag filter system in MWI-A was modified by splitting the activated carbon injection equally into two bag filters in series.…”

Section: Pcdd/f Removal Efficiencies Of the Dual-bag Filter Systemmentioning

confidence: 99%

The PCDD/F Removal Efficiency of a Medical Waste Incinerator Dual-Bag Filter System

Chen

Lin

Wang

et al. 2014

This study investigated the polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) removal efficiencies in two medical waste incinerators (MWIs) -MWI-A and MWI-B, with waste burning capacities of 9.12 and 12 tons per day, with dual-and single-bag filter systems, respectively. The PCDD/Fs in the stack flue gas and fly ashes of each air pollution control device (APCD) unit were collected concurrently. Based on mass balance, it was determined that the major PCDD/F removal occurred in the bag filter system with activated carbon injection (ACI). The total PCDD/F emission removal efficiencies for the whole dual-bag filter system, bag filter 1 (BF1), bag filter 2 (BF2) in MWI-A and the single bag filter system (BF) in MWI-B were 99.7%, 84.8%, 98.0%, 99.0% on the mass basis, respectively. The PCDD/F emission ratio (the escaped PCDD/F ratio after all APCDs) with the dual-bag filter system was over four times lower than that with a single bag filter. The results demonstrate a very efficient way to reduce the excess PCDD/F emissions incurred by intermittent operations and irregular waste feeding.

“…Air pollution control devices (APCDs), such as bag filters (Lin et al, 2008;Li et al, 2010;Yamada et al, 2011), electrostatic precipitators (EP) (Ruttanachot et al, 2011), activated carbon injection and other measures (Lai et al, 2007;Wang et al, 2008a), are used to remove pollutants from stack flue gases of stationary emission sources. Diesel particulate matter has been identified as a toxic air contaminant (Wenger et al, 2008), and diesel particulate filters (DPFs) are widely-used devices which can decrease the PM from diesel engine exhausts by up to 90%.…”

Section: Introductionmentioning

confidence: 99%

Reduction of Toxic Pollutants Emitted from Heavy-duty Diesel Vehicles by Deploying Diesel Particulate Filters

Hsieh

Wang

et al. 2011

In this study, the emission characteristics of PCDD/Fs, PCBs and PBDEs from heavy-duty diesel vehicles, and the reduction of these above toxic pollutants by deploying three kinds of diesel particulate filters (DPFs), that is, mobile metal filter plus catalyzed diesel particulate filter (MMF + CDPF), diesel oxidation catalysts (DOC) + CDPF and partial diesel particulate filter (PDPF) were investigated. The tested vehicles were maintained at 60 km/h for 10 minutes on a standard chassis dynamometer. The results show that vehicles with greater mileage had higher PCDD/Fs, PCB and PBDE concentrations in the exhaust. After the tested vehicles were equipped with DPFs, some trials showed the formation of PCDD/Fs and PCBs occurring inside the DPF. This could be due to the de novo and precursor formation resulting from the combined effects of the accumulated particulate in the DPFs, favorable temperature and longer retention time for the exhaust. The PDPF exhibited the largest reduction in these toxic pollutants emitted from HDDVs, which reached 83.9%-95.3% on mass basis, and 54.2%-71.9% on toxicity basis. However, significant differences existed among the trials of these three DPFs, revealing that the influential factors for the reduction of these toxic pollutants could be more complex than those for reduction of particulate matter.