本研究探討國內三座大型都市垃圾焚化爐(A、B及C廠)之空氣污染防制設備對重金屬的去除效率進而推估其排放係數。此外並針對採用活性碳控制技術前後之金屬回收廠(D廠)排氣進行採樣分析以探討重金屬排放特性之異同，為了更加瞭解SCR對汞物種分佈及去除效率的影響，亦針對三座設有SCR燃煤鍋爐(E、F及G廠)採樣分析，最後則是針對僅以EP控制粒狀物之水泥窯(H廠)作採樣分析。
研究結果顯示A、B及C三廠汞排放係數 (72.5、257.1及12.1 mg /ton)，相較於世界其它國家，A、C兩廠汞排放係數低於其它各國，最主要的差異為採用活性碳噴入技術，而B廠汞排放係數相較於世界上先進國家之焚化廠大致相當，就未採用活性碳噴入技術控制之B廠及金屬回收廠(D廠)而言 ，由於原物料性質不同，D廠汞排放係數(622.9 mg /ton)高出B廠(257.1 mg /ton)甚多，而D廠在噴入活性碳後，汞排放係數(46.2 mg /ton)明顯下降許多，目前國內法規並未針對金屬回收廠之重金屬排放立法規範，未來是否需訂定合理之排放規範亦或建議加裝活性碳噴入控制設備，值得有關單位重視。現行空氣污染法規標準針對大型廢棄物焚化爐之汞排放標準值為0.3 mg/Nm3，A、B及C三廠分析結果皆符合法規規範。
燃煤電廠中SCR一般用以減少NOX的排放。然SCR卻具有將元素態汞轉換成氧化態汞的能力，E、F及G廠採樣分析結果皆顯示SCR具有轉化能力，就G廠而言，由於採樣地點限制，故所SCR後端採樣所得之數據僅通過一層觸媒，導致SCR轉化效率並不明顯；本研究亦探討F廠各空氣污染防制設備對重金屬之去除效率，結果顯示重金屬總去除效率皆可高達95%以上，而汞亦有接近90%的去除效率，在氣相汞中，元素態汞於各APCD去除效率普遍偏低，而SCR卻能將元素態汞轉化為氧化態汞，有利於提升汞於後續濕式洗滌塔系統中的去除效率。針對僅設置EP的H廠，其煙囪汞氣相比率高達98%，推論H廠汞排放量控制不佳。
過去之研究顯示影響汞物種比率最重要的兩個因子分別為HCl濃度及溫度，故本研究亦利用軟體(Chemistry HSC)模擬典型都市垃圾焚化廠及燃煤鍋爐鍋爐出口之汞物種組成，並改變HCl濃度及溫度探討氧化態汞及元素態汞之比率關係。

On this study, stack samplings are conducted in three municipal solid waste incinerators (MSWI) with different air pollution controlling devices (APCDs) in Taiwan are conducted. To evaluate the removal efficiencies of heavy metals from the stationary sources, and the emission factors of heavy metals. Besides, this study also investigates Hg emission from a zinc recovery process (Zinc-D) which does not apply activated carbon injection (ACI) to control the emission of heavy metals in March, 2005. After applying ACI in November, 2005, stack samplings are conducted again at the end of the year. In order to understand how SCR affects the removal efficiency of Hg, this study selects three coal-burning plants equipped with SCR for NOX removal to conduct stack sampling.
The results indicate the emission factors of mercury at MSWI-A, MSWI-B and MSWI-C are quite different (72.5, 257.1 and 12.1 mg /ton, respectiviely). If we compared the results with other countries, MSWI-A and MSWI-C are relatively low, and the emission factor of mercury at MSW-B lies in between the range of other countries. The difference is caused by injection of activated carbon in domestic MSWIs to control dioxin emission. MSW-B is equipped with ACI, but it is not operated to avoid the increase of dioxin emission. As for the zinc recovery process with (DSC+CY+FF), the emission factor of mercury is calculated as 622.9 mg/ton waste, mercury emission from zinc recovery process is obviously higher than that of MSWI-A and MSWI-C, and it is also higher than MSW-B which does not apply ACI as APCD. When the zinc recovery process applies ACI, results indicate the emission factor of mercury is much lower than before (46.2 mg/ton). Although the feeding materials are different, we at least make sure factories which do not apply activated carbon injection technology might result in significant mercury emissions. The emission standard of Hg for large-scale MSWI in Taiwan is 0.3 mg/Nm3, all of the MSWIs investigated in this study are lower than the limit.
SCR is primarily applied to cut down NOX emissions from the power plants, however, SCR can transform elemental mercury into oxidized mercury. Results obtained in this study indicate that the removal efficiency of heavy metals (not including mercury) could reach 95%. As for mercury, the overall removal efficiency could also reach 90%, despite the removal efficiency of elemental mercury is relatively low. Based on this study (Plant-E, Plant-F and Plant-G), the SCR of all power plants can transform elemental mercury into oxidized mercury, but we only observe a little change of transformation from Plant-G, because the flue gas only passes through one layer of SCR reactor. When elemental mercury is transformed into oxidized mercury, it is easier to remove from gas streams through the APCD downstream such as wet scrubbers, and the overall mercury removal efficiency in power plant can be enhanced. Plant-H is equipped with EP only, so the percentage of vapor-phase mercury of the stack reaches 98%. We suspect the removal efficiency of mercury is not good at this plant.
Previous studies indicate that HCl concentration and temperature can affect mercury speciation. Our research changes the HCl concentration to investigate the percentage of mercury speciation. Besides, our study also simulates the mercury speciation of typical MSWI and power plant.

Alastuey, A., Jimenez, A., Plana, F. and Querol, X., and Suarez-Ruiz, I. “Geochemistry, mineralogy, and technological properties of the main Stephanian (Carboniferous) coal seams from the Puertollano Basin, Spain”, International Journal of Coal Geology, 45, 247-265 (2001).
Barton, R.G., Clark, W.D., Seeker, W.R. “Fate of metals in waste combustion systems,” Combustion Science and Technology, 74, 327-342 (1990).
Benson, S.A., Laumb, J.D., Crocker, C.R., and Pavlish, J.H. “SCR catalyst performance in flue gases derived from subbituminous and lignite coals”, Fuel Processing Technology 86, 577-613 (2005).
Black S. “Mercury and multi-emissions compliance strategies and tactics”, American Coal Council, 26-27 March Charoltte, NC (2004).
Brown, T., Dowd, W., Reuther, R. and Smith, D. “Control of mercury emission from coal-fired power plant: a preliminary cost assessment and the next step for accurately assessing control costs”, Fuel Processing Technology, 65-66, 311-341 (2000).
Carry, T.R., Skarupa, R.C. and Harrove, O.W. “Enhanced control of mercury and other HAPs by innovative modifications to wet FGD processing”, Phase Ι Report for the U.S. Department of Energy, Contract DE-ACC22-95PC95260, August.28 (1998).
Clarke, L.B. “The fate of trace elements during coal combustion and gasification: an overview”, Fuel Processing Technology, 72, 6, 731-736 (1992).
Chang, M.B., Wu, H.T., Huang, C.K. “Evaluation on speciation and removal efficiencies of mercury from municipal solid waste incinerators in Taiwan”, The Science of the Total Environment 246, 165-173 (2000).
Chu, P., Goodman, G. and Roberson, R. “Total and speciated mercury emission from U.S coal fired power plants”, Proceedings of the Air Quality Ⅱ: Mercury, Trace Elements, and Particulate Matter Conference, 34 (2000).
Hall, B., Schager, P. and Lindurvist, O. “Chemical reactions of mercury in combustion flue gases”, Water, Air, and Soil Pollution, 56, 15-20 (1991).
Huang, Y., Jin, B., Zhong, Z., Xiao, R., Tang, Z. and Ren, H. “Trace elements (Mn, Cr, Pb, Se, Zn, Cd and Hg) in emission from a pulverized coal boiler”, Fuel Processing Technology, 86, 23-32 (2004).
Feeley, T.J., L.A. Brickett, and J.T. Murphy, “Evaluation of the effect of SCR NOx control technology on mercury speciation,”Department of Engery, March 2003, Pittsburgh. U.S.A.
Fernandez, M.A., Martinez, L., Segarra, M., Garcia, J.C. and Epiell, F. “Behavior of heavy metals in the combustion gases of urban waste incinerators”, Environmental Science and Technology, 26, 1040-1053 (1992).
Galbreath, K.C. and Zygarlicke, C.J. “Mercury speciation in coal combustion and gasification flue gases”, Environmental Science and Technology, 30, 2141-2146 (1996).
Galbreath, K.C. and Zygarlick, C.J. “Mercury transformation in coal combustion flue gas”, Fuel Processing Technology, 65-66, 289-310 (2000).
Galbreath, K.C., Zygarlick, C.J., Tribbetts J.E., Schulz R.L. “Effects of NOx, α-Fe2O3, γ-Fe2O3, and HCl on mercury transformations in a 7-kW coal combustion system, Fuel Processing Technology, 86, 429-448 (2004).
Greenberg, R.R., Zoller, W.H. and Gordon, G.E. “Composition and size distributions of particles released in refuse incineration”, Environmental Science and Technology, 12, 566 (1978).
Ghorishi, S.B., Lee, C.W. and Kilgroe, J.D. “Mercury speciation combustion system: studies with simulated flue gases and model fly ashes”, Proceedings of the Air and Waste Management Association, 92nd Annual Meeting and Exhibition, St. Louis USA, 99-651 (1999)
Hower, J.C., Robel T.L., Anderson C., Thomas, G.A., Clark C.L., “Characteristics of coal combustion products (CCP’s) from Kentucky power plants, with emphasis on mercury content”, Fuel, 84, 1338-1350 (2005).
James, P.S., Raveendra, V.I. and Timothy, E.F. “Multivariate statistical examination of spatial and temporal patterns of heavy metal contamination in new Bedford harbor marine sediment”, Environmental Science and Technology, 29, 1781-1788 (1995).
Kotnik, J., Horvat M., Mandic, V., Martina, L., “Influence of the Sostanj coal-fired thermal plant on mercury and methyl mercury concentrations in Lake Velenje, Slovenia,” The Science of the Total Environment, 259, 85-95 (2000).
Krivanek, C.S., “Mercury control technologies for MWCs”, the unanswered questions”, Journal of Hazardous Materials, 47, 119-136 (1996).
Laudal, D.L., Heidt, M.K., Brown, T.D.; Nott, B.R.; Prestbo, E.P.; “Mercury speciation: a comparison between EPA Method and other sampling methods”, 89th Annual Meeting & Exhibition of AWMA, Nashville, Tennessee, Paper 96-WA64A.04 (1996).
Laudal, D.L., Brown, T.D. and Nott, B.R. “Effects of flue gas constituents on mercury speciation”, Fuel Processing Technology, 65-66, 157-165 (2000).
Laudal, D.L., Thompson, J.S., Pavlish, J.H., Brickett, L., Chu, P., Srivastava, R.K., Lee, C.W. and kilgroe, J.D. “Evaluation of mercury speciation at power plants using SCR and SCR NOx control technologies”, 3rd International Air Quality Conference, Arlington, Virginia, September 9-12 (2002).
Lee, C.W., and Srivastava, R.K. “Pilot-scale study of the effect of selective catalytic reduction catalyst on mercury speciation in Illinois and powder river basin coal combustion flue gases”, Journal of Air and Waste Management Association 56, 643-649 (2006).
Lee, C.W., Kilgroe, J.D. and Thompson, J.S. “Speciation of mercury in the presence of coal and waste combustion fly ashes”, 93rd Air & Waste Management Association Annual Meeting & Exhibition, Salt Lake City, UT, June 18-22 (2000).
Linak, W.P.; Wendt, J.O.L.; “Toxic metal emissions from incineration: mechanisms and control,” Prog. Energy Combust. Science, 19, 145-185 (1993).
Licate, A., Balles, E. and Schuttetnhelm, W. “Mercury control alternative for coal-fired power plants”, 10th Annual NAWTEC Conference, Orlando, USA (2002).
Lindbaure, R.L., Wurst, F. and Prey, T. “Combustion dioxin suppression in municipal solid waste incineration with sulfur additives”, Chemosphere, 25, 1409 (1992).
Masaki, T., Nobuo, T., Takeshi, F., Masato, K., Tetsuo, K. “Control mercury emission from a municipal solid waste incinerator in Japan,” Journal of AWMA, 52, 8,931-940 (2002).
Martinez-Tarazona, M.R. and Spears, D.A. “The fate of trace bulk minerals in pulverized coal combustion in a power station”, Fuel Processing Technology 47, 79-92 (1996).
Meij, R. and Winkel, T.T. “The emission and environmental impact of PM10 and trace elements from a modern coal-fired power plant equipped with ESP and wet FGD”, Fuel Processing Technology, 85, 641-656 (2004).
Minghou, X., Rong, Y., Chugang, Z., Yu, Q., Jun, H. and Changclong, S. “Status of trace element emission in a coal combustion processing：a review”, Fuel Processing Technology 85, 215-237 (2003).
Munthe, J., Wangberg, I., Iverfeldt, A., Lindqvist, O., Stromberg, D., Sommar, J., Gardfeldt, K., Petersen, G., Ebinghaus, R., Prestbo, E., Larjava, K. and Seimens, V. “Distribution of atmospheric mercury species in North Europe: final results from the MOE project”, Atmospheric Environment, 37, 1, 9-20 (2003).
Nadziakiewic, J. and Michal, K. “Co-combustion of sludge with coal”, Applied Energy, 75, 293-248 (2003).
Niksa, S., Helble, J. and Fujiwara, N. “Kinetic modeling of homogeneous mercury oxidation: The importance of NO and H2O in predicting oxidation in coal-derived systems”, Environmental Science and Technology, 35, 3701-3706 (2001).
Nishitani, T., Fukunaga, I., Itoh, H., Nomura.T. “The relationship between HCl and mercury speciation in flue gas from municipal solid waste incinerations,” Chemosphere, 39(1), 1-9 (1999).
Norton, G.A., Yang, H., Brown, R.C., Laudal, D.L., Dunham, G.E., Erjavec, J., “Heterogeneous oxidation of mercury in simulated post combustion conditions”, Fuel, 82, 107–116 (2003).
Otani, Y., Kanaoka, C., Usui, C., Matsui, S. and Emi, H. “Adsorption of mercury vapor on particle”, Environmental Science and Technology, 20, 735-738 (1986).
Pai, P., Niemi, D., Power, B., “A north American inventory of anthropogenic mercury emission,” Fuel Processing Technology, 65, 101-115 (2000).
Pacyna, J.M., “Estimation of the atmospheric emissions of the trace elements from anthropogenic sources in Europe”, Atmospheric Environment, 8, 41 (1984).
Pavlish, J.H., Sondreal, E.A., Mann, M.D., Olson, E.S., Galbreath, K.C., Laudal, D.L. and Benson, S.A. “Status review of mercury control options for coal fired power plants”, Fuel Processing Technology, 82, 89-165 (2003).
Puxbaum, H. “Metal compounds in the atmosphere”, E. (eds.) Metals and Their Compounds in the Environment”, VCH, New York (1991).
Qiu, J., Sterling, R.O., Helble, J.J. “Development of an improved model for determining the effects of SO2 on homogeneous mercury oxidation”, 28th International Technical Conference on Coal Utilization and Fuel Systems, FL(2003)
ROC EPA, 2004. Environment programs: implementation of the construction. http://www.epa.gov.tw/english/officies/wastetoenergy.doc (2004).
ROC EPA, 2005. Environment programs: implementation of the construction project of waste to energy plants in Taiwan. http://ivy3.epa.gov.tw/swims/ (2005).
Sliger, S., Kramlich, J.C., Marinov, N.M. “Towards the development of chemical kinetic model for the homogeneous oxidation of mercury by chlorine species”, Fuel Processing Technology, 65-66, 423-438 (2000).
Senior, C.L., Morency, G.P., Huffman, G.P., Huggins, F.E., Shah, N., Peterson, T., Shadman, F. and Wu, B. “Interaction between vapor-phase mercury and coal fly ash under simulated utility power plant flue gas condition ’’, Air and Waste Management Association，91st Annual Meeting and Exhibition, June.14-18, 98-RA79B.04 (1998).
Senior, C.L., Helbel, J.J. and Sarofim, A.F. “Emission of mercury, trace element, and fine particle from stationary combustion sources”, Fuel Processing Technology, 65, 263-288 (2000).
Shuckerow, J.I., Steciak, J.A., Wise, D.L., Levendis, Y.A., Simons, G.A., Gresser, J.D., Gutoff, E.B. and Livengood, C.D. “Control the air toxic particle and vapor emission after coal combustion utilizing calcium magnesium acetate”, Resources, Conservation and Recycling, 16, 15-69 (1996).
Stanislav, V.V. and Christina, G.V. “Geochemistry of coal ashes and combustion wastes from coal-fired power stations”, Fuel Processing Technology 51, 19-45 (1997).
Srivastava, R.K., C.W. Lee, B. Ghorishi,W. Jozewicz, and T.W. Hasting, “Evaluation of SCR catalysts for combustion control of NOx and mercury,” Joseph Hirschi, ICCI, Final Technology Report, 02-1/2.2A-1 (2003).
Tan, Y., Mortazavi, R., Dureau, B. and Douglas, M.A., “An investigation of mercury distribution and speciation during coal combustion”, Fuel, 83, 2229-2236 (2004).
Tillman, J.M. “Estimation of the atmospheric emissions of the trace elements from anthropogenic sources in Europe”, Atmospheric Environment, 8, 41, (1989).
US EPA, “Announces first rule mercury emission from power plant”, U.S.EPA, March 3 (2005).
Vogg, H., Metzger, M.; Stieglitz, L., “Recent findings on the formation and decomposition of PCDD/PCDF in municipal solid waste incineration”, Waste Management and Research, 5, 285-294 (1987).
Wey, M.Y., Hwamg, J.H., Chen, J.C. “The behavior of heavy metal Cr, Pb and Cd during waste incineration in fluidized bed under various chlorine additives ” , Journal Chemical Eng. of Japan, 29, 496-505 (1996).
Wu, C.Y.; Biswas, P. “An equilibrium analysis to determine the speciation of metals in incineration ”, Combustion and Flame, 93, 31-40 (1993).
Wu, B., Peterson, T.W., Shadman, F., Senior, C.L., Morency, J.R., Huggins, F.E. and Huffman, G.P. “Interactions between vapor-phase mercury and coal char under simulated utility power plant flues gas condition”, Fuel Processing Technology, 63, 93-108 (2000).
Yongxin, Z., Michael, D.M., Olson E.S., Pavlish, J.H., Grant E. D. “Effect of sulfur dioxide and nitric oxide on mercury oxidation and reduction under homogeneous conditions”, Journal of Air and Waste Management Association 56, 628-635 (2006).
Zhao, L.L., and Rochelle, G.T. “Mercury adsorption in aqueous oxidants catalyzed by mercury (Ⅱ), Ind. Eng. Chem. Res., 37, 380-387 (1998).