燃煤鍋爐及燃油鍋爐細懸浮微粒排放檢測與特性分析比較

Characterization and Comparison of Fine Particulate Matter Emitted From Coal- and Oil-Fired Boilers

吳至晏(Jhih-Yan Wu)

指導教授 ： 楊錫賢

朝陽科技大學/理工學院/環境工程與管理系/碩士(2017年)

摘要

本研究針對固定污染源之燃煤鍋爐與燃油鍋爐進行細懸浮微粒(PM2.5)採樣與分析，採樣方法參照USEPA之Method 201A與Method 202進行PM2.5的採集，其中部分採樣點同步以USEPA CTM-039進行稀釋採樣比較，解析PM2.5排放特性與化學組成，並建立燃煤與燃油鍋爐PM2.5排放係數與指紋圖譜。本研究共進行21根次燃煤鍋爐與12根次燃油鍋爐PM2.5煙道檢測，結果顯示燃煤鍋爐過濾性與凝結性PM2.5平均濃度分別為5.99 ± 12.9與7.85 ± 9.12 mg/Nm3；燃油鍋爐過濾性與凝結性PM2.5平均濃度則分別為13.9 ± 7.80與267 ± 369 mg/Nm3，凝結性微粒佔PM2.5平均比例分別為64.4%與83.0%。設置不同防制設備對過濾性PM2.5排放濃度影響顯著，燃煤鍋爐設置旋風分離器、靜電集塵器及袋式集塵器平均過濾性PM2.5排放濃度分別為23.8 ± 2.40、2.07 ± 2.09與1.19 ± 1.69 mg/Nm3；燃油鍋爐無設置任何微粒防制設備之過濾性PM2.5排放濃度為15.5 ± 5.99 mg/Nm3，設置旋風分離器與靜電集塵器分別為13.5 ± 13.0及0.07 mg/Nm3。燃煤鍋爐排放之過濾性PM2.5中的碳成分、水溶性離子與金屬元素佔總PM2.5 (過濾性加凝結性PM2.5)比例分別為9.41%、12.5%與4.84%，凝結性PM2.5中的水溶性離子與金屬元素佔總PM2.5(過濾性加凝結性PM2.5)比例分別為29.0%與5.59%。在燃煤鍋爐PM2.5 (FPM + CPM)化學組成中以凝結性PM2.5之水溶性離子所佔比例最高，濃度較高物種分別為SO42-、Cl-與NH4+，代表這些物種與凝結性PM2.5的形成有一定關係。凝結性PM2.5之排放可能受燃料、製程、操作條件與煙道排氣溫度所影響，本研究結果發現排氣溫度為影響凝結性PM2.5於總PM2.5 (FPM + CPM)所佔比例重要因子，在燃料、製程與防制設備皆一致的情況下，排氣溫度與凝結性PM2.5於總PM2.5 (FPM + CPM)所佔比例其之相關係數R2為0.444 (n = 9)。本研究以煙道內熱採樣與稀釋採樣同步進行燃煤鍋爐PM2.5排放檢測濃度分別為13.7 ± 3.62與5.74 ± 2.98 mg/Nm3 (n = 2)，若將稀釋採樣測值視為實際PM2.5排放值，煙道內熱採樣法測值較稀釋採樣法測值高，稀釋採樣法測值平均為煙道內熱採樣法的42.6%。本研究所建置之燃煤與燃油鍋爐圖譜顯示，燃煤鍋爐主要物種為OC、EC、SO42-、NH4+與Fe，燃油鍋爐為OC、EC、SO42-、NH4+與Ca2+。兩種鍋爐因原料不同使得特徵物種有些許差異，但主要共同物種皆以OC、EC、SO42-與NH4+為主。煙道內熱採樣法建立之排放係數中，若以原(燃)料使用計算之燃煤與燃油鍋爐PM2.5排放係數(包括FPM與CPM)分別為122 ± 104 g/ton與5850 ± 7548 g/KL；依每單位發電量為基準估算PM2.5排放係數平均為36.8 ± 21.6與193 mg/kWh；依每單位蒸氣產量估算PM2.5平均排放係數分別為28.4 ± 26.8與479 ± 556 g/ton-vapor。雖然重油相較生煤是較潔淨的燃料，但因為燃煤鍋爐皆裝設較完善的微粒防制設備，使得PM2.5排放係數平均皆低於燃油鍋爐。

關鍵字

固定污染源 ； PM2.5 ； 鍋爐 ； 稀釋採樣 ； 排放係數 ； 化學指紋圖譜

並列摘要

Abstract
In this study, fine particulate matter (PM2.5) emitted from coal- and oil-fired boilers were sampled with USEPA Method 201A and Method 202 (in-stack hot sampling method). Some of the samples were simultaneously collected with USEPA CTM-039 (dilution sampling method). Chemical compositions (carbon, water soluble ions and metals) of the collected PM2.5 were analyzed. Emission characteristics are investigated and emission factors and fingerprints of PM2.5 from coal- and oil-fired boilers are established. The results show that filterable and condensable PM2.5 concentrations from coal-fired boiler are 5.99 ± 12.9 and 7.85 ± 9.12 mg/Nm3, respectively. The filterable and condensable PM2.5 concentrations from oil-fired boiler are 13.9 ± 7.80 and 267 ± 369 mg/Nm3, respectively. The condensable PM2.5 accounts 64.4% and 83.0% for coal- and oil-fired boilers, respectively. For coal-fired boilers, the filterable PM2.5 concentrations are 23.8 ± 2.40, 2.07 ± 2.09 and 1.19 ± 1.69 mg/Nm3 for the plants with cyclone separator, electrostatic precipitator and bag house installed. For oil-fired boilers, the filterable PM2.5 concentrations are 15.5 ± 5.99, 13.5 ± 13.0 and 0.07 mg/Nm3 for the plants without any particle control equipment, installed with cyclone and electrostatic precipitators, respectively. For coal-fired boilers, carbon, ions and metal elements in filterable PM2.5 account for 9.41%, 12.5% and 4.84% of total (filterable + condensable) PM2.5. Water soluble ions and metal elements in condensable PM2.5 account for 29.0% and 5.59% of total (filterable + condensable) PM2.5. The species in condensable PM2.5 are dominated by water soluble ions, including SO42-, Cl- and NH4+. The results indicate that condensable PM2.5 is formed primarily by water soluble ions. Temperature is an important factor affecting propotion of condensable PM2.5 in total PM2.5. The correlation coefficient (R2) is 0.444 for temperature and percentage of condensable PM2.5 in total PM2.5, indicating positive correlation between the percentage of condensable PM2.5 and the exhaust temperature. PM2.5 concentrations (filterable + condensable) are 13.7 ± 3.62 and 5.74 ± 2.98 mg/Nm3 measured by in-stack hot sampling method and dilution sampling method for coal-fired boilers. PM2.5 concentration is 2.68 times higher measured by in-stack hot sampling method than that by dilution sampling methid. The results of chemical composition analysis show that the major species in PM2.5 are OC, EC, SO42-, NH4+ and Fe for coal-fired boilers, and are OC, EC, SO42-, NH4+ and Ca2+ for oil-fired boilers. The emission factors for coal- and oil-fired boilers are 122 ± 104 g/ton and 5850 ± 7548 g/KL, respectively. In terms of electricity produced, PM2.5 emission factors are 36.8 ± 21.6 and 193 mg/kWh for coal- and oil-fired boilers, respectively. In terms of steam produced, PM2.5 emission factors are 28.4 ± 26.8 and 479 ± 556 g/ton-vapor for coal- and oil-fired boilers, respectively. Although heavy oil is a cleaner fuel than coal, most coal-fired boilers are equipped with better particle air control equipment. PM2.5 emission factors of coal-fired boiler are lower than those of oil-fired boilers.

並列關鍵字

Emission sources ； PM2.5 ； Boiler ； Dilution sampling technique ； Emission factors ； Chemical source profile

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