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研究生:黃盛修
研究生(外文):Sheng-Hsiu Huang
論文名稱:小型靜電集塵器之過濾及負載特性之研究
論文名稱(外文):The Study of Filtration and Loading Characteristics of Miniature Electrostatic Precipitators
指導教授:陳志傑陳志傑引用關係
指導教授(外文):Chih-Chieh Chen
學位類別:博士
校院名稱:國立臺灣大學
系所名稱:職業醫學與工業衛生研究所
學門:醫藥衛生學門
學類:公共衛生學類
論文出版年:2001
畢業學年度:89
語文別:中文
論文頁數:170
中文關鍵詞:靜電集塵器微粒粒徑微粒負載
外文關鍵詞:electrostatic precipitatorsparticle sizeparticle loading
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靜電集塵器是許多工業製程中常用的空氣污染控制設備之一,此外也被運用於住家以及餐廳中以去除空氣中之過敏物與香菸微粒,以保護人體健康及避免家俱因微粒的沈積而受到污染。在研究中藉著評估一小型靜電集塵器之過濾特性,以瞭解不同粒徑微粒、流量、電場強度以及放電極電性等因素如何影響靜電集塵器之收集效率以及所產生的臭氧濃度;其次,以兩種具有不同電阻特性之固體微粒(水泥與氧化鋁)以及DOP液體微粒以進行微粒負載之研究,在過程中同時量測粉餅累積的厚度、靜電集塵器之收集效率、電暈電流量以及臭氧的產生量以探討微粒負載的影響;除此之外,在研究中也探討了兩種型式(單階與雙階)的靜電集塵器對於超細微粒之捕集效率,並使用兩種微粒充電器,以探討微粒充電時是否會有遮蔽效應的發生。
結果顯示,小型靜電集塵器之氣懸微粒貫穿率隨操作電壓的增加而降低,以0.3 mm為例,在流量30 L/min下,當操作電壓為+4 kV時,其微粒貫穿率為96 %,而當電壓提昇至+8 kV時,貫穿率則降至15 %。若電壓固定為+8 kV,則當氣流量由30 L/min增加至120 L/min時,0.3 mm微粒的貫穿率約提高54 %。至於其最易穿透粒徑約在0.25至0.5 mm之間。在臭氧的產生量方面,於相同電場強度之下,負電暈所產生的臭氧濃度則為正電暈的5倍。
微粒負載方面,當以水泥為測試粉塵時,在固定的供電壓下,電暈電流量會隨著粉餅厚度的增加而降低,同時,其收集效率與臭氧產生量也會隨著負載的時間增加而降低。以供電壓為-27kV下經過120分鐘的測試後,粉餅厚度約為5 mm,此時電暈電流與臭氧產生量約分別比一開始之數值降低33%與44%,而對於最易穿透粒徑0.3 mm的微粒之收集效率則降低4%。然而若以氧化鋁微粒進行負載之測試,雖然由於電暈電流隨著負載的進行而增加,以致於造成臭氧產生量的提高,但是其收集效率卻是呈現下降的趨勢,主要是因為氧化鋁微粒具有較高的電阻係數,因此在負載的過程中會有背電暈的現象出現,以致於造成微粒穿透率、電暈電流量以及臭氧產生量的增高。另外從粉餅的外觀上亦可看出氧化鋁粉餅確實會造成背電暈的發生。另外在水泥的負載過程中發現,約在進行後的20分鐘時,電暈電流量有一徒升的現象,然後再逐漸地下降,同時也反映在臭氧的產生量上,主要是由於電暈放電模式的改變所造成的。
從實驗與理論的比較結果發現,微粒粒徑在數十奈米(nanometer)範圍確實存在著充電不足的現象。以實驗中所使用的單階與雙階靜電集塵器為例,其對於粒徑分別約在20 nm 50 nm以下的微粒之收集效率有顯著的降低。另外,就節約能源的觀點,使用單階靜電集塵器來處理粒徑小於16 nm的微粒是較具經濟效益的,否則以雙階靜電集塵器較具效益。
對於濃度在105 #/cm3的奈米微粒在擴散充電器中,並未發現有明顯的遮蔽效應;相反地,對於微米粒徑範圍的微粒在電場充電器中,當微粒濃度達2 × 104 mm2/cm3以上,則可以看出明顯的遮蔽效應產生。
ESPs are one of the most commonly employed devices for collecting particulates from many industrial processes. They are also used in homes as well as in restaurants to remove allergens and tobacco smoke from the ambient air, so as to protect people and reduce soiling of interior surfaces and furnishings. This study investigated the filtration characteristics of a miniature dual saw-like electrodes ESP. Parameters such as particle size, rate of airflow through the ESP, voltage of the charge electrode, and discharge polarity were considered to study their influence on aerosol penetration through the ESP, ozone generation, and energy consumption. Moreover, in order to investigate the particle loading effects, simultaneous measurements of the dust cake thickness accumulated on the collection plates, ESP’s collection efficiency, corona discharge characteristics, and ozone concentration were conducted experimentally. On the other hand, the penetrations of ultra-fine particles through a single- and a two- ESPs were measured as a function of particle size. The masking effect on particle charging was also studied.
Experimental results indicated that the aerosol penetration through the ESP decreased (from 96 % to 15 % for 0.3 mm) as the voltage of the discharge electrode increased (from +4 kV to +8 kV) at a flow rate of 30 L/min. At a fixed electrode voltage (+8 kV), aerosol penetration increased from 15 % to 69 % for 0.3 mm particles as the flow rate increased from 30 to 120 L/min. The most penetrating particle size was in the range of 0.25 mm to 0.5 mm depending on the discharge voltage and the flow rate. In general, the most penetrating particle size of the ESP decreased with decreasing discharge voltage or with increasing flow rate. Ozone generated by the ESP with negative polarity was about five times greater than that generated with positive polarity. Therefore, when using an ESP as an indoor air cleaner, the search for an optimum balance between ozone production and aerosol collection efficiency should be considered.
When challenged with cement particles, the corona current decreased with increasing dust cake thickness under a constant applied voltage. Moreover, the collection efficiency and ozone generated by corona discharge decreased as the loading test progressed. For example, after about 120 minutes loading test, the output current and the ozone concentration decreased about 33% and 44%, respectively, and the collection efficiency (300 nm particle) decreased about 4% at a fixed applied voltage of —27 kV. However, the corona current increased as aluminum oxide particles were deposited on the collection plates. Therefore, the ozone generated by corona discharge was increased, but decreasing in the collection efficiency. The increase of aerosol penetration, corona current and ozone concentration may cause partly by the phenomenon of back corona. The occurrence of back corona can be approved by the existence of the caves on the dust layers. In the case of testing with cement particles, the corona current rises after about 20 minutes of loading test, and then decreases with time, while ozone concentration increases synchronously. However, the mechanism of this phenomenon is not well understood, and needs further investigation.
It is confirmed from the comparison of experimental and theoretical results that partial charging regime exits when the particle diameter is several tens of nanometer. Experimental results indicated that the aerosol penetration through the single- and two-stage ESPs increased significantly for particles below 20 and 50 nm, respectively. However, the exact regime depends on the parameters including air flow rate, applied voltage, and the configurations of an ESP as well.
Experimental results indicate that, when charged by the diffusion charger, the masking effect was not observed for nanoparticles with a number concentration less than 1 × 105 #/cm3. However, with the field charger the masking effect was obvious when it was challenged with micrometer particles that had a surface area concentration above 2 × 104 mm2/cm3.
Preface…………………………………………...…………I
中文摘要……………………………………………...…………II
Abstract……………………………….………………………..III
目錄…………………………………………………..…………V
圖目錄……………………………………………………………..VII
表目錄…………………………………………………………..X
第一章 內容概要
一、研究緣起與目的………………………………………...1
二、文獻探討…………………………………………………..5
2-1靜電集塵器的種類…………………………………………5
2-2微粒充電………………………………………………………6
2-3臭氧的產生……………………………………………………9
三、研究材料與方法…………………………………….……..13
3-1氣懸微粒的產生………………………………………....13
3-2氣懸微粒的量測………………………………………....14
3-3靜電集塵器之特性描述………………………………………14
四、結果與討論………………………………………………...15
4-1電流與電壓之關係…………………………………………15
4-2 臭氧的產生…………………………………………………15
4-3氣懸微粒穿透率………………………………………….....15
4-4微粒負載對靜電集塵器之影響………………………………17
4-5微粒充電之遮蔽效應實驗……………………………………18
五、結論………………………………………………………...20
六、參考文獻……………………………………………..……21
第二章 Dual Saw-like Electrode ESP…………..………..58
第三章 Loading Characteristics of a Miniature Wire-Plate Electrostatic Precipitator…………………………………93
第四章 Ultra-fine Aerosol Penetration through Electrostatic Precipitators..….............................125
第五章 Masking Effect on Particle Charging……………151
American Lung Association. When You Can''t Breathe, Nothing Else Matters. 1996. From http://www.lungusa.org/noframes/global/news/report/viron/virozonefac.html.
Awad, M. B., and Castle, G. S. P., Ozone Generation in an Electrostatic Precipitator with a Heated Corona Wire. J. Air Pollut. Control Assoc. 25:369-374, 1975.
Benson, S. W., and Axworthy, A. E., Reconsideration of the Rate Constants from the Thermal Decomposition of Ozone. J. Chem. Phys. 42:2614-2615, 1965.
Boeniger M.F., Use of Ozone Generating Devices to Improve Indoor Air Quality. American Industrial Hygiene Association Journal 56: 590-598, 1995.
Castle, G. S. P., Inculet, I. I., and Burgess, K. I., Ozone Generation in Positive Corona Electrostatic Precipitators. IEEE Trans. Ind. Gen. Applicat. IGA-5:489-496, 1969.
Chang, C.L. and Bai, H., An Experimental Study on the Performance of a Single Discharge Wire-plate Electrostatic Precipitator with Back Corona. J. Aerosol Sci. 30(3): 325-340, 1999.
Cheng, Y.S., Yeh, H.C, and Kanapilly, G.M., Collection Efficiencies of a Point-to-plane Electrostatic Precipitator. Am. Ind. Hyg. Assoc. J. 42: 605-610, 1981.
Davison, R.L., Natusch, D.F.S., Wallace, J.R. and Evans, C.A.Jr, Trace Elements in Fly Ash — Dependence of Concentration on Particle Size. Envir. Sci. Technol. 8:1107-1113, 1974.
Flagan, R.C. and John, H.S., Fundamental of Air Pollution Engineering, Chapters 5 and 7, Prentice Hall Inc., 1988.
Foard K et al., Investigation of Gas-Phase Ozone as a Potential Biocide. Appl. Occup. Environ. Hygiene. 12: 535-542, 1997.
Gooch, J.P. and Francis, N.L., A Theoretically Based Mathematical Model for Calculation of Electrostatic Precipitator Performance. J. Air. Poll. Contr. Assoc. 25(2): 108-113, 1975.
Leonard, G., Mitchner, M. and Self, S.A., Particle Transport in Electrostatic Precipitators. Atmos. Environ. 14: 1289-1299, 1980.
Lippmann M, Health effects of ozone: A critical review. J. Air Pollution Control Assoc. 39:672-695, 1989.
Makin, B., and Inculet, 1. 1., Generation of Ozone from Heated Positive Corona Wires for Electrostatic Charging. Eighth Annual Meeting of IEEE Industrial Application Society (L4S), ES-TUE-PM5, vol. 5, pp. 381-389, 1973.
McLean, K.J., Electrostatic Precipitators. IEE Proc. 135(6): 347-362, 1988.
Nashimoto, K., The Effect of Electrode Materials on O3 and NOx Emissions by Corona Discharging. J. Imaging Sci. 32:205-210, 1988.
Nelson, H.S., Hirsch, S.R, Ohman, J.L., Platts-Mills, T.A.E., Reed, C.E., and Solomon, W.R. Recommendations for the Use of Residential Air-Cleaning Devices in the Treatment of Allergic Respiratory Diseases, J. Allergy Clin. Immunol. 82(4):661-669, 1988.
Offermann FJ, Sextro RG, Fisk WJ, et al., Control of Respirable Particles and Radon Progeny with Portable Air Cleaners. Berkeley, Calif.: Lawrence Berkeley Laboratory (LBL-16659), Feb 1984.
Ohkubo, T., Hammasaki, S., Nomoto, Y., Chang, J.S., and Adachi, T., The Effect of Corora Wire Heating on the Downstream Ozone Concentration Profiles in an Air Cleaning Wire-Duct Electrostatic. Precipitator. IEEE Trans. Ind. Apphcat. 26:542-549, 1990.
Reiser, K M., Tyler, W. S., Hennessy, S. M., Dominquez, J. J., and Last, J. A., Long-term Consequences of Exposure to Ozone. Toudcol. Appl. PharmacoL. 89:314, 1987.
Shaughnessy R.J., Leventin E., Blocker J. and Sublette K.L., Effective of Portable Indoor Air Cleaners: Sensory testing results. Indoor Air 4: 179-188, 1994.
The Merck Index, Merck Research Laboratories Division of MERCK & CO., Inc., 12th ed.:7112-7113, 1996.
U.S. Environmental Protection Agency, Office of Air and Radiation. Report to Congress on Indoor Air Quality, Volume II: Assessment and Control of Indoor Air Pollution, pp. I, 4-14. EPA400-1-89-001C, 1989.
U.S. EPA, EPA''s Updated Clean Air Standards: A Common Sense Primer September 1997. Available at http://www.epa.gov/oar/primer/
U.S. EPA, Health and environmental effects of ground-level ozone. OAQPS Fact Sheet, July 17, 1997. Available at http://ttnwww.rtpnc.epa.gov/naaqsfin/o3health.htm.
U.S. EPA, National Air Quality and Emissions Trends Report, 1996, Research Triangle Park, NC 27711, US EPA, 1996.
U.S. EPA, Ozone generator in indoor air settings. Report No. EPA-600/R-95-154, 1995.
Viner, A- S., Lawless, P. A., Ensor, D. S., and Sparks, L. E. Ozone Generation in DC-Energized Electrostatic Precipitators. IEEE Trans. Ind. Applicat. 28:504-512, 1992.
White H.J., Electrostatic precipitation of fly ash. J. Air. Poll. Contr. Assoc. 27: 15-21, 114-120, 206-217, 308-318, 1977.
White, H.J., Trans. Am. Inst. Elect. Engrs., 70:1186-1191, 1951.
Witschi, H., Ozone, Nitrogen Dioxide and Lung Cancer: A Review of Some Recent Issues and Problems. Taricolo. 48:1-20, 1988.
Yagi, S., and Tanaka, M., Mechanisms of Ozone Generation in Air-Fed Ozonisers. J. Phys. D, AppL Phys. 12:1509-1520, 1979.
Yoo, K.H, Lee, J.S., and Oh, M.D., Charging and Collection of Submicron Particles in Two-Stage Parallel-Plate Electrostatic Precipitators. Aerosol Sci. Technol. 27: 308-323, 1997.
Zhao, Z.M., and Robert, P., A Semi-Empirical Approach to Predict the Total Collection Efficiency of Electrostatic Precipitators. Chem. Eng. Comm. 148-150: 315-331, 1996.
張峰義:退伍軍人病十個問題簡介。http://www.iosh.gov.tw/frame.htm,1996。
李芝珊、林雅晴、侯博安與蕭欣杰:室內空氣品質問題調查研究─空氣清淨機效能之評估。EPA86—FA41—09—05,1997。
王秋森:氣懸膠技術學。國立台灣大學醫學院出版委員會出版,頁:74-81,1993。
行政院勞委會:勞工安全衛生法規彙編(三)─勞工作業環境空氣中有害物容許濃度標準,頁283,1997。
行政院環保署─環境保護法規:Display Graph。 來源:http://w3.epa.gov.tw/epalaw/index.htm
行政院環境保護署環境檢驗所─環境檢驗通訊雜誌:淺談室內空氣品質。來源:http://www.epa.gov.tw/analysis/publish/month/13/8.html.
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