選擇性觸媒還原程序應用於排氣中NOx之控制已行之有年，其催化反應活性主要由釩氧化物提供，操作於300到400oC方能達到高去除效率，相關研究也證實SCR觸媒對於戴奧辛有很好的去除效果。本研究探討應用自製SCR觸媒同時去除戴奧辛與NOx之效率，並進一步添加貴重金屬進行觸媒改質，藉由貴重金屬的高催化活性以提升對污染物之催化特性。另一方面同時尋找具備多重污染物去除潛力之貴重金屬進行改質，以落實多重污染物排放控制策略 (multipollutant emission control)。文獻證實Ru具高轉化活性，且成本相較於其他Pt、Pd貴重金屬低。故本研究以V2O5/TiO2觸媒為基礎，添加Ru金屬進行改質，並製備多種不同成分配比之觸媒，以獲取較佳之觸媒成分。研究結果指出戴奧辛類污染去除方面，V2O5/TiO2觸媒反應溫度由150oC提升至300oC對於戴奧辛去除效率有正面之影響。5wt%V2O5/ TiO2在反應溫度為150oC時，對PCB之去除部分仰賴觸媒吸附效果而未實際與觸媒進行反應，破壞效率為68.9%;當溫度提升至200oC時，效率始有顯著提升，其去除機制方達到以觸媒破壞為主要動力，破壞效率達94.6%。改質後Ru/5wt%V2O5/TiO2觸媒在溫度150oC時顯著提升PCB破壞效率。在NOx去除方面，NO轉換效率受NH3添加劑量之影響較為顯著，在NH3:NO為1.2時，5wt%V2O5/TiO2對NO之轉換效率隨操作溫度上升而有顯著提升，並在300oC達99%;在NH3:NO為1時，溫度操作在250oC達最高效率為73%，副產物量測方面，操作溫度由300oC上升至400oC開始有明顯N2O之生成，並進一步發現N2O生成可能由NH3氧化生成，而觸媒之釩氧化物成分越高也會提升N2O生成之趨勢。經改質後3wt%Ru/ 5wt%V2O5/TiO2在300oC和350oC發現有更高NO轉換效率分別為79.8%、88.5%，並且對於N2O之生成有抑制作用。Selective catalytic reduction (SCR) is a well-established and widely used process for the abatement of NOx present in waste gases from stationary sources. The catalytic activity is mainly provided by vanadium oxide and it has to be operated at a temperature range of 300oC-400oC to achieve high NOx removal efficiency. Previous study indicates that the SCR catalyst can also be applied for PCDD/Fs removal. This study investigated the self-made traditional SCR catalyst for simultaneous removal of dioxin and NOx from gas streams, and modified the catalyst for higher activity and multiple pollutant removal. Literature confirmed that Ru is of high activity and the cost is lower than other noble metals, such as Pt and Pd. In this study, V2O5/TiO2 is modified by adding Ru, with different percentages. Experimental results indicate that Ru/5wt%V2O5/TiO2 catalyst significantly improves dioxin destruction efficiency at 150oC. For the removal of NOx, the modified 3wt%Ru/5wt%V2O5/TiO2 achieved higher NO conversion efficiencies of 79.8%, and 88.5%, respectively, at 300oC and 350oC, and also reduced N2O formation.
