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半乾式除酸系統的優點有(1)耗水量少，(2)操作溫度高於露點時腐蝕性低
，(3)產生乾的廢棄物且易於處理。文獻中對於酸性氣體去除的研究，大
多以半乾式鹼性吸附劑吸附模擬的酸性氣體，但對於在實際煙道氣中複雜
的氣體組成下，其去除效果的詳細討論並不多。而吸附劑於煙道中乾燥後
具有很大的表面積，對於一些無法（未）燃燒的物種(例如揮發性重金屬
蒸氣)的吸附效果也未見討論。因此，本研究在不同的焚化操作條件下，
探討以半乾式系統同時去除煙道氣中重金屬微粒及酸性氣體之效果。實驗
中針對鉻(Cr)、鉛(Pb)、鎘(Cd)三種對人體較具危害性的重金屬，探討在
不實驗結果顯示，在除酸方面氯化氫的去除效率均在97.8%以上，添加劑
對去除氯化氫的影響並不明顯。在去除二氧化硫方面，以二氧化矽為添加
劑的除硫效果最好，效率為71.3%，添加氯化鈣的除硫效率為66.0%，未添
加添加劑為63.1%。而不同當量比的除硫效率隨著當量比提高而升高，當
量比為2時，去除效率為82.7%。對於重金屬去除方面，主要針對旋風集塵
器收集的飛灰加以分析，結果發現：煙道未經處理所產生的飛灰，雖比半
乾式處理時產生的飛灰有較高的金屬濃度。但由於半乾式處理產生飛灰量
較高，就總量來說，半乾式處理所捕捉的重金屬量仍較多。半乾式洗滌塔
中添加添加劑對重金屬之攔截、凝附影響，由實驗中可發現不論是在單一
金屬進料或混合金屬進料，由於添加二氧化矽產生的顆粒分散性良好，顆
粒粒徑大多居於37-74μm區間，而這個粒徑範圍為重金屬濃度較高的粒經
範圍，因此在半乾式吸收劑中添加二氧化矽添加劑的捕捉金屬量最高。
英文提要:Semi-dry system is conventionally employed to remove
the SOx, NOx, and HCl in the flue gas. Semi-dry system provides
the advantages of (1) few water demand. (2) less corrosion when
the operating temperature is higher than dew point, and (3) dry
products are formed, which are easy to dispose. The removal
efficiency of acid compounds with alkaline sorbents in simulated
flue gas has been investigated in previous studies. However, the
removal efficiency of acid gas in the practical flue gas, which
cTherefore, the primary object of this study was to focus on the
removal efficiency of acid gas and heavy metal (Cr, Cd, Pb)
consistently under various operating condition. The mass element
size distribution of heavy metal in fly ash under different
additives was also investigated. The obtained results indicated
the removal efficiency of hydrogen chloride in semi-dryer was
higher than 97.8%. The effect of additives on the removal
efficiency of HCl, however, were undistinguished. In
desulfurization process, the highest removal efficiency was
71.3% with the additive of silicon-dioxide in the spray-drying
alkaline sorbent. The removal efficiency is 66.0% with the
additive of calcium chloride, and 63.1% without any additive. It
was also found that semi-dry process can decrease the
concentration of metal in fly ash but increase the amounts of
fly ash. In addition of silicon-dioxide in alkaline sorbent
leaded towards increasing the adsorption of heavy metal on
reactants, because silicon-dioxide additives enhanced the
alkaline sorbent dispersal.
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