| 摘要: | 選擇性催化還原(Selective Catalytic Reduction, SCR)技術因其可同時去除NO、VOC和PCDD/Fs的能力而引起了廣泛關注。對於面臨設備升級挑戰的傳統產業而言，同時去除技術能夠有效節省成本並符合排放標準，非常具有吸引力。燒結過程是包括NO、VOC和PCDD/Fs在內的主要空氣污染物來源。然而，不同污染物在同時去除過程中的相互作用會影響其去除效果。因此，本研究旨在評估三種SCR觸媒對氣流中NO、甲苯和PCDD/Fs同時去除的潛力。氣流包含200 ppm的NO、200 ppm的NH₃、50 ppm的SO₂、3%的O₂、14%的H₂O(g)和1 ng-TEQ/Nm³的PCDD/Fs，以5000 h⁻¹ 的氣體小時空速（GHSV）和220°C的溫度進行評估。為了研究VOC的同時去除，將固定濃度的甲苯（380 ppm）注入氣流中進行測試。應用了三種不同的商業V2O5-MoO3/TiO2 (VMT)觸媒。XRF、BET和XRD分析結果顯示，這三種VMT觸媒在比表面積和鉬含量上存在明顯的差異。研究結果表明，這些觸媒確實具有同時去除三種污染物的能力。具有最高MoO₃ 含量的Cat-1，在三種同時去除的污染物中表現出最佳的去除效率，戴奧辛達到93.1%、NO達到83.3%、甲苯達到81.1%。另外也觀察到具有較高抗硫成分（如SiO₂、WO₃）的Cat-2儘管其鉬含量較低，但在H₂O(g)和SO₂存在時顯示出較高的NO和PCDD/Fs去除效率，這可能歸因於含硫抗性物質引起的表面酸性增加，影響了氨和PCDD/Fs在觸媒表面的吸附。然而，對戴奧辛的破壞效率及甲苯轉化率而言，僅與觸媒比表面積大小及活性金屬含量呈正相關。同時，對於高氯數的OCDD及OCDF物種，發現在220℃的操作溫度下僅能實現較有限的吸附與破壞。本研究結果指出各污染物在多污染物控制 (multipollutant control, MPC) 過程中受不同氣流條件的變化影響，並呈現良好的同步去除效率。;Selective Catalytic Reduction (SCR) technology has garnered widespread attention due to its capability to simultaneously remove NO, VOCs, and PCDD/Fs. Industries are facing the challenge, of equipment upgrade to meet the stringent emission standards and multi-pollutant control (MPC) technology is highly attractive as it effectively reduces the costs and space. Sintering process is a major source of air pollutants, including NO, VOCs, and PCDD/Fs. However, the interactions among different pollutants during the simultaneous removal process can affect the removal efficiency. Therefore, this study aims to evaluate the potential of three SCR catalysts for simultaneous removal of NO, toluene, and PCDD/Fs from gas stream. The gas stream contains 200 ppm NO, 200 ppm NH₃, 50 ppm SO₂, 3% O₂, 14% H₂O(g), and 1 ng-TEQ/Nm³ PCDD/Fs. The experimental tests were conducted at a gas hourly space velocity (GHSV) of 5000 h⁻¹ and a temperature of 220°C. To investigate the simultaneous removal of VOCs, toluene (380 ppm) was added to the gas stream for testing. Three different commercial V2O5-MoO3/TiO2 catalysts were applied. The results of XRF, BET, and XRD analysis indicated significant differences in specific surface area and molybdenum content among three VMT catalysts. The experimental results showed that these catalysts indeed possess the capability to simultaneously remove three pollutants from gas stream. Cat-1, with the highest MoO3 content, exhibited the best removal efficiency among the three pollutants, achieving 93.1% for dioxins, 83.3% for NO, and 81.1% for toluene. Additionally, Cat-2, which contains higher sulfur-resistant components such as SiO₂ and WO3, demonstrated higher removal efficiency for NO and PCDD/Fs in the presence of H₂O(g) and SO₂, despite its lower molybdenum content. This might be attributed to the increased acidity caused by sulfur-resistant materials, which influenced the adsorption of ammonia and PCDD/Fs on the catalyst. Destruction efficiency of dioxins and the conversion rate of toluene were positively correlated with the catalyst′s specific surface area and active metal content. Furthermore, limited adsorption and destruction were achieved at the operating temperature of 220°C for highly chlorinated OCDD and OCDF species. The results highlight the variations in pollutant removal efficiency under different gas stream conditions in the MPC process, demonstrating good overall removal efficiency. |
