- 學位論文
以微波反應沸石處理一氧化氮之研究
A Study of Nitric Oxide Treatment by Zeolite With Microwave System
摘要
氮氧化物是造成酸雨和光化學煙霧的重要前趨物之一，控制氮氧化物排放量的方法可分為燃燒控制與後燃燒控制，但是在很多情況下，燃燒控制並不能很有效的達到所要求的標準，所以需以後燃燒控制法來處理氮氧化物。其中又以選擇性觸媒還原法較為普遍，但是其在還原過程中還原劑的溢散、腐蝕等問題還有待解決，所以再找尋更合適的技術是刻不容緩的事。 本研究製備碳改質沸石(C-ZSM5)，並利用微波誘導催化作用處理一氧化氮，微波可使C-ZSM5內部迅速加熱，產生活性熱點，NO分子以這些活性熱點位為反應中心，與C-ZSM5發生還原反應，轉化為N2。 研究結果顯示，C-ZSM5之質量越多，氮氧化物去除效率隨之增加，以本實驗系統操作，最佳去除效率條件為180g的C-ZSM5於300W之微波功率下，可使NO達到90%以上之去除效率。此外，利用微波加熱反應，使C-ZSM5表面溫度隨微波輸出功率增加而上升，以微波輸出功率300W為例，加熱15分鐘後可達到約110℃。 由SEM和BET分析結果顯示，與未改質之ZSM-5相比，C-ZSM5增加些許碳材之熔融狀物質，但可能造成孔洞阻塞，使C-ZSM5比表面積下降，當反應微波功率越高，C-ZSM5微孔體積有增加的趨勢，比表面積隨之上升。
並列摘要
Nitrogen oxides (NOX) are important precursors of acid rain and photochemical smog. Combustion controls and post-combustion controls are the two main categories for NOx emission reduction techniques. However, combustion controls along are not effective enough to achieve the regulation requirement in most cases. Therefore, adaptation of post-combustion controls to remove NOx from the exhausted stream is usually needed. Amongst all the pos-combustion techniques, SCR method is one of the common practices. Yet, during the process of most SCR method, the corrosive reductants can lead to further pollution. As a result, developing alternative control technology is of the highest priority to effectively reduce NOx emission for the industry. This research used thecarbon-zeolite socony mobil (C-ZSM5) to absorb NO, and employedmicrowave discharge to assisted catalysis C-ZSM5. C-ZSM5 internalwasrapidly heatedto a high temperaturetoproduce an activehot spot,these activehotspot reduced NO in C-ZSM5, and NO converted toN2. The results show that the conversion of NO to N2 increased with the amount of C-ZSM5 increased. The optimum conversion efficiency of NOcould reach above 90% with microwave power of 300W andamount of C-ZSM5 was 180g. Temperature of the C-ZSM5 rose gradually and reached to approximately 110℃under microwave power output was 300W after 15 minutes. The higher microwave power output was, the higher temperature of C-ZSM5was. The adsorption on and desorption from C-ZSM5 concern with a porous system, that may differ from slit to spherical shaped properties. According to SEM and BET analysis, the C-ZSM5 was covered by the carbon materials successfully. However, the carbon material may causeholesobstruction, and then the specific surface area of C-ZSM5 was decreased. As the microwave power increased, the specific surface area of C-ZSM5 was increased. Accordingly, the C-ZSM5 was supposed to have larger micropore volume and specific surface area under 500 W of microwave power.