Nguyin Thi Thu ThiJy vd Dtg Tgp chi KHOA HOC & CONG NGHE 126(12); 107 111 DEVELOPMENT OF EMISSION FACTORS FOR QUENCHING PROCESS TO EMISSIONS INVENTORY Nguyen Thi Thu Thuy*, Nguyen Thi Hanh, Nguyen Thi[.]
Nguyin Thi Thu ThiJy vd Dtg Tgp chi KHOA HOC & CONG NGHE 126(12); 107-111 D E V E L O P M E N T O F EMISSION FACTORS FOR QUENCHING PROCESS TO EMISSIONS INVENTORY Nguyen Thi Thu Thuy*, Nguyen Thi Hanh, Nguyen Thi Thu Phuong College of Technology - TNU SUMMARY At the coking plant, there are many manufacturing processes which generate air pollutants and impact on the environment, including coke quenching Inventory of emission of coke production process make significant contribution to air pollution control and environmental management In this studying, concentrations of pollutants being CO, SO2, NO, in coke quenching process were determined Samples of gaseous pollutants in the flue were collected using a stack sampler of APEC XC572-V and following USEPA methods 6, 7, 10 Based on monitoring and the process information, total emissions and emission factors of these pollutants for this process were determined Based on burning fiiel, the emission factors of CO, SO2, and NO2 in the experiment were 0.029 mg/kg; 0.012 mg/kg; and 0.004 mg/kg, respectively Alternatively, based on coke product, the emission factors of CO, SO2, and NO2 in the experiment were 0.035 mg/kg; 0.015 mg/kg; and 0.005 mg/kg, correspondingly The results obtained from the research can be used for industrial emission inventories and air quality management in Viet Nam KeywordsiAlr polluani, coke quenching, emission, emissionfiiclor,inventory INTRODUCTION An emission factor is a representative value that attempts to relate the quantity of a pollutant released to the atmosphere with an activity associated with the release of that pollutant Emission inventories are fundamental tools for air quality management They are used for identifying major contributors of atmospheric pollutants, developing emission control strategies, determining applicability of permitting programs, and other related applications [4] Metallurgical coke is produced by the destructive distillation of coal in coke ovens Prepared coal is heated in an oxygen-fi-ee ahnosphere (-cooked-) at 950-I050°C until most volatile components in the coal are removed The material remaining is a carbon mass called coke [5] At the coke plant, there are many manufacturing processes which generate air pollutants to impact on the environment, including coke quenching However, data on emission factors for coke production is scarce includmg Viet Nam This ' Email: Tkuynguyenktml@tnuudu v Study; therefore, aims to develop the emission factors of coke production in Vietnamese conditions This paper presents preliminary results on the emission factors of coke quenching process for Thai Nguyen Iron and Steel Joint Stock Company MATERIALS AND METHODS Process description This study was conducted at Coking Factory of Thai Nguyen Iron and Steel Joint Stock Company There are three main houses in this company including coking house, chemistry house, and steel rolling house, From raw coal storage, coal is put into bunker and is pushed to mixing bins and, at which, the coal is usually a blend of two or more kinds of coal Then, it is heated in sealed chamber without air with the temperature inside oven reaching from 950''C to 1050°C in 20 minutes At the end of process, the coke is pushed through a coke guide into a special railroad car called a quench car The quench car carries the coke to a quench tower where it is deluged with water to prevent the coke from burning after exposure to air When 107 Nguyen Thj Thu Thuy vd Dtg 126(12; 07-111 Tap chi KHOA HOC & CONG NGHE coke is cold, it is crushed, screened and gone to coke storage Emission and cootrol There are many emission points in coke production such as door emissions, combustion stack emissions, pushing emissions, quenching emissions etc which were shown in Figure In this research, quenching emissions were chosen to study The flue gas of coke quenching, after being treated by a spray tower scrubber (made of stainless steel, 4m high) and a tray tower absorber (made of stainless steel, 6.2 m high), is emitted into the atmosphere at the height of 33m via an exhaust pipe on the top of the absorber This exhaust pipe is 2m high and lm in diameter There is a monitoring port located at 1.5 m from the open end of this exhaust pine This monitoring port was used for the stu Sampling and analytical methods Samples were collected at the same time of a batch of coke quenching production on March (CTI), May (CT2), and August (CT3) in 2014, based on US EPA methods 6, 7, 10 for SO2, NOx, CO, respectively Then, samples were preserved and analyzed in laboratory following TCVN 7242:2000, TCVN 6750:2005, TCVN 7172:2002 for CO, SO2, NO2, respectively Calculation method Emission: The total emission of eacli pollutant is calculated by the following formula: Total emission = C|.L.t (mg) (1) Where, C, is the concentration of each pollutant (mg/m^), L is the flow of flue gas (m^/h) and t (h) is the monitoring time Emission factors: The emission factors of each pollutant are calculated by the following formula: (2) EF,= t-fiieKi-producl Where, EF, is the emission factor of each pollutant, E, is the emission of each pollutant and Efiiei/Eproduct are the amount of fliel and product, respectively Emission rates: The emission rates of each pollutant are calculated by the following formula: ERr (3) Where, ER, is the emission rate of each pollutant, E, is the emission of each pollutant and t (h) is the monitoring time Figure 1: Some major emission points in coke production Nguyen Thj Thu Thuy vo Dig Tgp chi KHOA HQC & CONG NGHE 126(12): 107 - 111 Figure Diagram of the flue gas treatment system and monitoring port RESULTS AND DISCUSSIONS Concentration of air pollutants Average concentrations of the pollutants in the flue gas of coke quenching process were shown in Table As can be seen from Table 1, while the concentration of SO2, NO, were not so high, concentration of CO was extremely high and exceeded the respectivestandardof QCVN19:2009/BTNMT[2] In coke oven, coal is heated in sealed chamber without air, the insufficient led to complete combustion Therefore, the concentration of CO is so high Table I: Summary Information of the flue gas of coke quenching production Concentration Temperature Flow rate Sample NO, TCO (Nm'/h) CO (rag/Nm') SOjCmg/Nra') (mg/Nm') CTI 50000 1200.81 225.43 84-85 86.83 CT2 50000 1208.24 228.72 84-85 96.34 CT3 50000 1210.84 84-85 226.74 106.25 1206.6±5.2 Average 226.96±1.7 96.47±9.7 Emission factors Based on the data of monitoring, total emissions were calculated following (1) with sampling time was twenty minutes Then, emission factors of air pollutants were calculated following (2) and results were shown in Table Table 2: Emission factors of coke quenching production Emission factor(mg/kg) Average Average amount of amount of CO SO, NO, coal/batch coke/batch Coal Coke Coal Coke Coal Coke (kg) based based based based based based (kg) 7900 6500 0.029 0.035 0.004 0.005 0.012 0.015 Data on emission factors in this study were compared with other studies Data on the emission factors of gaseous pollutants available in the open literature are mainly for the whole coking process Data for specific steps of this process are very scarce Data on emission factors in the step of coke furnace pushing and controlled door leak emission can be considered to be the same range with those of coke quenching [4] The results in this study were also compared with the study of Thuy et al [3] As can be seen in Figure 3, the emission factors of NO and SO2 in this study were relatively similar with those of Thuy's study However, there are some differences between the results in this study and those of Thuy's study although two experiments were conducted in the same place 109 NguySn Thi Thu Thuy vo Dig Tap chl KHOA HOC & CONG NGHE 0.06 0.04 ' J - NOx S02 DThis study • 14] Figure 3: Comparison of emission factors CO In Thuy's study, they used combustion gas analyzer to measure directly the concentration of pollutants Type of function was chosen on the least standard error using SPSS version 16.0 The total emission of a pollutant was the obtained by intergrading the function of this pollutant for the whole time of a batch Different study method leads to the differences of these results can be easily under stood Table 3: Emission rates ofeoke quenehing production Emission Annual Pollutants rates (mg/h) Emission (ton/year) NO, 88.76 0.73 SO, 290.51 2.18 CO 675.71 5.27 Emission rates and annual emission Emission factor is a good basis to compare pollutant emission from emission from combustion of different fuels Emission rates are usually expressed as the weight of pollutant emitted divided by duration of the activity emitting die pollutant The emission rates are calculated following (3) Based on data 126(12) 1U7-111 on emission factors can be inventoried total annual attnosphere of CO, SO2, NO, for coke quenching and result are shown in Table Among atmospheric pollutants, total annual emission of CO is the highest It is the major agent to impact on the health of workers and air pollution in this area CONCLUSIONS In this study, emission factors including CO, SO2, NOjof coal-based and coke-based were determined in coke quenching processfor Thai Nguyen Iron and Steel Joint Stock Company The emission rates and the total annual emission of CO, SO2, NO, were also determined Emission factors in this study are in the same range with other studies, and the results make confribution to Viet Nam database of emission factors for coke product REFERENCES E.HasSnen, L.Aunela-Tapola,V Kinnunen, et al " Emission Factors and annual emissions of bulk and trace elements from oil shale fueled power plants, The Science of the Total Environment 1997 MONRE QCVN 19:2009/BTNMT; National Technical Regulation on Indusfrial Emission of Inorganic Substances and Dusts.Hanoi,2009 Nguyen Thi Thu Thuy, Nghiem Tmng Dung "Determination of emission factors for coke quenching" Journal of science & Technology Technical untversities No 87, 2012, pages 64-46 US Environmental Protection Agency Procedures for Preparing Emission Factor Documents USA, 1997 US Environmental Protection Agency "Emissions Factors Documentation for AP 42, Section 12.2: Coke Production".US A, May2008 Nguyin Thi Thu Thiiy vd Dig Tap chi KHOA HOC & CONG NGHE 126(12): 107 - 111 TOM TAT XAY DyNG HE SO PHAT THAI CHO QUA TRINH DAP COC PHUC VU CONG TAC KEEM KE KHI THAI Nguyin Thi Thu Thuy*, Nguyen Thj Hanh, Nguyin Thj Thu Phirong Trudng Dgi hoc Ky Thuat Cong Nghiep - DH Thdi Nguyen Tai nha miy coc hoa, c6 nhieu qua trinh san xuat sinh thai gSy anh huong ldn dSn moi truong khong khi, d6 c6 qua trinh dap coc Kigm ke phit thai ctia qua trinh sin ?< udt c6c d6ng gdp vai tr6 vo ciing quan trgng kiem so^t nhilm khong v i quan ly moi •ni6ng Trong nghign cu-u nay, nong dp c^c chdt nhilm CO2, SO3, NO^ qui trinh dap coc d t g c xac dinh Mau thai dugc thu thgp bang mdy APEC XC572-V vk theo phucmg phap US EPA 6, 7, 10 Dua vio dil li6u quan trSc va thong tin ve qua trinh coc hda, t6ng iuong phat thai va h6 s6 phdt thai ciia nhimg chat nhiem dugc xdc djnh Tinh todn dya tren lui^ng nhi§n ligu, hS s6 phat thai CO, SO2, vd NO2 thi nghigm ISn lupt la 0,029 mg/kg; 0,012 mg/kg; va 0,004 mg/kg Dua vao san pham than c6c, cac hg s6 phdt thai ciia CO, SO2, va N02trong thi nghiem tuong ung la 0,035 mg/kg; 0,015 mg/kg; vd 0,005 mg/kg Cac kgt qua thu dugc tir nghign ciiu co thi dugc sir dung cho kilm kg thdi cong nghiep vd quan ly chdt lugng khong tai Viet Nam Tu kh6a: thdi, ddp eoc, phdt thdi, he sdphdt thdi kiim ke Ngdy nhdn bdi' 15/9/2014; Ngdy phdn bien:09/10/2014; Ngdy duyet ddng: 25/10/2014 Phan biin khoa hoc: TS Mgc Duy Huy - Trudng Dai hoe Ky thudt Cdng nghiep - DHTN ' Email: Thuynguyenktmt@tnut.edu ... emissions, quenching emissions etc which were shown in Figure In this research, quenching emissions were chosen to study The flue gas of coke quenching, after being treated by a spray tower scrubber (made... combustion gas analyzer to measure directly the concentration of pollutants Type of function was chosen on the least standard error using SPSS version 16.0 The total emission of a pollutant was... Thu Thiiy vd Dig Tap chi KHOA HOC & CONG NGHE 126(12): 107 - 111 TOM TAT XAY DyNG HE SO PHAT THAI CHO QUA TRINH DAP COC PHUC VU CONG TAC KEEM KE KHI THAI Nguyin Thi Thu Thuy*, Nguyen Thj Hanh, Nguyin