Characteristics of dioxin and furan emissions from selected electric arc furnaces in Vietnam

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) released from thermal processes of various industries have urgently concerned. Stack gas samples were collected from selected electric arc furnaces (EAFs) in Vietnam in order to investigation of PCDD/F concentration, congener profile and emission factors. U.S EPA method 23 was used following the requirements for isokinetic sampling of stack gas emission.
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Characteristics of dioxin and furan emissions from selected electric arc furnaces in VietnamVNU Journal of Science: Earth and Environmental Sciences, Vol. 32, No. 2 (2016) 79-84Characteristics of Dioxin and Furan Emissions from SelectedElectric Arc Furnaces in VietnamNguyen Van Thuong1,2,*, Do Quang Huy2, Nguyen Hung Minh11Center for Environmental Monitoring, Vietnam Environmental Administration,No. 556, Nguyen Van Cu, Hanoi, Vietnam2Faculty of Environmental Science, Hanoi University of Science, No. 334 Nguyen Trai, Hanoi, VietnamReceived 08 January 2016Revised 22 January 2016; Accepted 28 June 2016Abstract: Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs)released from thermal processes of various industries have urgently concerned. Stack gas sampleswere collected from selected electric arc furnaces (EAFs) in Vietnam in order to investigation ofPCDD/F concentration, congener profile and emission factors. U.S EPA method 23 was usedfollowing the requirements for isokinetic sampling of stack gas emission. The quantification ofPCDD/Fs was carried out by high resolution gas chromatography, coupled with high resolutionmass spectrometry (HRGC/HRMS). The results suggested that mass concentration and TEQ ofPCDD/F in stack gas samples from EAFs in Vietnam ranged from 0.077–2.26 ng/Nm3 and 0.027–0.264 ngTEQ/Nm3, respectively. Emission factors of PCDD/Fs are determined in the range of 0.89– 2.03 µgTEQ/ton of product. Emission factor of PCDD/F from the EAF plants in Vietnam wereequivalent to those in some countries in Asia, but higher than those of the industrialized countriesin European Union.Keywords: PCDD/Fs, EAFs, Stack gas, Emission Factors.incinerators remain as a major source from theindustrial activities, responsible for 30-56, 38and 87%, respectively, of the total emissions(UNEP, 1999) [1]. In the UK [2], the emissionsfrom metal sector including sinter plants, steeland non-ferrous metals, contribute in totaldioxin emissions from 15 to 26%. ThePCDD/Fs emissions inventory in Taiwan hasreported that sinter plants and electric arcfurnaces were more important sources thanfrom waste incinerators, contributing 32 and23% to the total emissions, respectively [3].In Vietnam, steel industry was growing at arate of 13.2% per year during 2005-20091. Introduction∗Dioxin contamination from Agent Orangein Vietnam has been received much attentionfor the past decades. Besides that,polychlorinateddibenzo-p-dioxinsandpolychlorinated dibenzofurans (PCDD/Fs)released from thermal processes of variousindustries have urgently concerned. Theindustrialized countries such as the UK, the USand Japan, emission of PCDD/Fs from waste_______∗Corresponding author. Tel.: 84-987623268Email: thuongnv@vea.gov.vn7980N.V. Thuong et al. / VNU Journal of Science: Earth and Environmental Sciences, Vol. 32, No. 2 (2016) 79-84(UNIDO, 2012) [4]. In the same period, thesteel consumption demand increased by about15.7% per year and reached a total consumptionestimated of 15.37 million tonnes in 2009.About 95% of steel plants use electric arcfurnaces (EAFs) for the production processes[4]. The EAF process includes stages offeeding, smelting, oxidation, reduction andsteel discharge.This is one of the first studies in Vietnam toinvestigate PCDD/Fs emissions from EAFplants. The data from this study will providemore understanding about the emissions ofPCDD/F in the country and contribute to itsdevelopment of inventory of PCDD/F.2. Experiment2.1. Sample collectionFour typical EAF in Luu Xa, Thai BinhDuong, Dana-Y and Bien Hoa steel plants havebeen selected for investigation of dioxin andfuran release to the air. Basic informationregarding the investigated plants is given inTable 1. The stack gas samples (consisting ofboth particulate and gas phases) in each of theselected EAFs were isokinetically sampled inaccordance the method 23 of the United StatesEnvironment Protection Agency (U.S EPA,1998) [5]. Samples of stack gas were takenusing the ESC C5000 sampling train(Environment Supply Company, USA). Beforesampling, XAD-2 resin was spiked with13CPCDD/F surrogate standards. Particulatephase was collected on a quartz fiber filter(QFF, Pall Corporation, USA). The isokineticpercent for stack gas sampling conducted in thisstudy ranged from 95 to 103%, which is in anacceptable range of the US EPA method 23(90–110%). In order to control crosscontamination, travel blank and field blanksamples were taken during each sampling event.2.2. Chemical analysesChemical analysis of PCDD/F was carriedout using following method 23 (U.S EPA,1998)withHighresolutionGaschromatography coupled with High resolutionMass spectrometer (HRGC/HRMS). Seventeen2,3,7,8-substituted PCDD/F congeners wascarried out by isotope dilution method usingMicromass Autospec Ultima system (Waters,UK) with Agilent 7890A gas chromatograph(GC) and DB-5MS capillary column (60 m ×250 µm i.d × 0.25 µm film thickness, J&WScientific Inc., Folsom, CA). The procedure forsample preparation and equipment operationhave described in the previous study [6].The stack gas samples include XAD2 resinand quartz fiber filter were Soxhlet extractedusing toluene for 24 hours. The extracts wereconcentrated and treated by sulfuric acid (98%).Clean-up and fractionation steps wereperformed using pre-packed silica column,alumina column, and activated carbon column.Quantification of seventeen 2,3,7,8-substitutedPCDD/Fs congeners were carried out byHRGC–HRMS. The method detection limitswere 1.00 and 2.00 pg/Nm3 for tetra-CDD/Fsand penta- to octa-CDD/Fs congeners,respectively [6].Toxicity Equivalent Factors (TEFs) schemeby the World Health Organization (WHO,2005) were used for the calculation of TEQ andcomparison in this study. Based on the TEQconcentrations of the investigated EAFs, theemission factors of PCDD/F ...