| 摘要: | 氣候變遷對環境造成之影響不容輕忽，近年來造成世界各地乾旱、熱浪及暴雨發生情況頻率暴增，透過降低溫室氣體的排放，可減緩地球暖化，降低極端氣候的發生。氫為潔淨燃料更具有零碳排能源載體潛力，分解氨氣產生氫氣並導入燃煤或燃氣發電系統，部分取代煤及天然氣以提高發電效率是達到淨零碳排的重要手段之一。本研究以含浸法製備 10 wt% Fe-Ni/MgO 及 Ru/MgO兩種觸媒，研究主軸分為兩個部分，一為熱催化系統之效率探討，另一則是利用觸媒結合電漿進行氨氣分解生產潔淨能源氫氣，藉由改變參數(空間流速、濃度及操作電壓等)探討對氨分解效率之影響。實驗結果顯示使用電漿+Ru/MgO觸媒系統之氨分解率隨空間流速先減而後增，與純電漿系統及電漿+Fe-Ni/MgO觸媒之趨勢不同，在空間流速為1800 mL/g．h時，電漿+Ru/MgO觸媒有最大之氨分解率(75.2%)，產氫能量效率隨著電壓增加而上升，為兩種系統中唯一呈向上趨勢者。在高操作電壓(≧12 kV)且空間流速為7200 mL/g．h時，使用電漿結合觸媒系統之氨分解效率較純電漿系統佳，可看到電漿結合觸媒之協同效應，且在高操作電壓下添加觸媒之系統有較好之產氫能量效率。就空間流速而言，在低操作電壓下，氣體停留時間越長(空間流速越低)，純電漿系統之產氫能量效率優於電漿結合觸媒系統，而在空間流速為7200 mL/g．h下電漿結合觸媒系統之產氫能量效率 > 純電漿系統之產氫能量效率。就氨氣進樣濃度而言，在高操作電壓下，可發現電漿結合觸媒系統有進流濃度為20%之產氫能量效率 > 30%之產氫能量效率 > 10%之產氫能量效率之趨勢。本研究證實電漿觸媒可有效分解氨以生成潔淨的氫氣，深具發展潛力。;The impact of climate change on the environment cannot be ignored. In recent years, the frequency of droughts, heatwaves, and heavy rains has surged worldwide. Reducing greenhouse gas emissions can mitigate the global warming and decrease the occurrence of extreme weather, highlighting the urgency of carbon reduction. Hydrogen is a clean fuel with potential as a zero-carbon energy carrier. Decomposing ammonia to produce hydrogen and integrating it into coal on gas power systems to partially replace coal and natural gas can improve power generation efficiency, making it a key strategy for countries to achieve net-zero carbon emissions. This study involves the preparation of 10 wt% Fe-Ni/MgO and Ru/MgO catalysts via impregnation method. It focuses on two main parts: application of the thermal system and the plasma-catalyst system for ammonia decomposition to produce clean hydrogen. The study explores the effects of operating parameters (space velocity, concentration, and operating voltage) on ammonia decomposition efficiency. The experimental results show that the ammonia decomposition rate achieved with plasma + Ru/MgO catalyst system first decreases and then increases with space velocity, a trend different from that of the pure plasma system and the plasma + Fe-Ni/MgO catalyst. At a space velocity of 1800 mL/g·h, the plasma + Ru/MgO catalyst system achieves the highest ammonia decomposition rate (75.2%). The hydrogen energy efficiency increases with increasing voltage, showing a unique upward trend among the systems. At high operating voltages (≥12 kV) and a space velocity of 7200 mL/g·h, the conversion of NH3 achieved with plasma-catalyst system surpasses that of the pure plasma system, demonstrating the synergistic effect of the plasma-catalyst combination. At high operating voltages, the system with the added catalyst exhibits better hydrogen energy efficiency. In terms of space velocity, at low operating voltages, the hydrogen energy efficiency achieved with pure plasma system is superior to that of the plasma-catalyst system with longer gas residence time (lower space velocity). At a space velocity of 7200 mL/g·h, the hydrogen energy efficiency of the plasma-catalyst system exceeds that of the pure plasma system. Regarding ammonia feed concentration, at high operating voltages, the plasma-catalyst system shows a trend with the hydrogen energy efficiency at a 20% feed concentration > 30% > 10%. This study has demonstrated that combined plasma catalysis is effective in decomposing ammonia to generate hydrogen and has the potential for industrial application. |
