碩士生: 馮椲裎
畢業年分: 2020年7月
論文名稱: 甲烷/空氣預混火焰通入鐵、鐵-鋁，與鐵-煤之顆粒燃燒特性探討(中文) / Particle combustion characteristics of iron, iron mixed with aluminum, and iron mixed with coal in methane-air premixed flames (英文)
中文摘要:
高能金屬燃料，視為一種潔淨且可回收的能源載體，係具有前瞻的反應材料（reactive materials），可用於未來的低碳經濟。高能量密度的金屬材料是具有發展潛力，得以取代目前能源領域中所使用的化石燃料，以應對迫在眉睫的全球變暖和能源危機問題。本研究的主要目是在於分析和探討純鐵顆粒和混合顆粒（鐵-鋁和鐵-煤）在甲烷-空氣預混火焰中的燃燒行為。混合顆粒是以重量配比為1：1的條件下製備而成。 鐵和鐵-煤的熱重分析顯示，在相對低的溫度範圍內，氧化反應過程相似。然而，鐵-鋁混合物則表現出多級氧化過程。在較小的固態燃料進料速度範圍內，選用微米級固體燃料輸送至化學當量條件下的甲烷-空氣預混火焰進行研究。在提高固態燃料進料速度時，實驗結果顯示會改變預混火焰的鋒面。進行一系列相關實驗探索固體燃料與甲烷-空氣預混火焰之間的相互依賴性以及一些基本燃燒現象的變化，例如燃燒速度，火焰溫度，氣體排放和金屬氧化物產物。此外，在鐵-煤混於甲烷-空氣預混燃燒中觀察到顆粒微爆炸（particle micro-explosion）現象。推測一氧化碳氣體被捕集於薄壁且多孔性的氧化鐵顆粒內部，並導致開始羰基鐵（iron carbonyl）的生成。最後，在氧化鐵微粒中的可燃性一氧化碳與羰基鐵誘發微爆炸。為了驗證與支持所提出的粒子微爆炸機理之推論，在混合鐵-甲烷-空氣燃燒中加入了一氧化碳與金屬有機框架材料（Metal Organic Frameworks，簡稱MOF）粉末以觀察是否有顆粒微爆炸之誘發。
英文摘要:
High energetic metal fuels, regarded as a clean and recyclable energy carrier, are promising reactive materials to apply for the future low-carbon emission. Higher energy density materials are the potential to substitute fossil fuel in energy sectors for coping with the imminent global warming and energy crisis issues. In this study, the main purpose is to analyze and investigate the combustion behaviors of pure iron particles and mixing particles, namely, iron-aluminum and iron-coal in hybrid methane-air premixed flames. The mechanically mixing particles were prepared based on the weight with a ratio of 1:1. Thermal gravimetry analysis for Fe and Fe-Coal illustrates similar oxidation range in a quite low-temperature region, whilst Fe-Al mixture presents a multi-stage oxidation process. Methane-air conical premixed flame in the stoichiometric condition was seeded with micron-sized solid fuels over a small range of feeding rates. It appeared that an increase of solid particles seeding would alter the hybrid flame front. A series of relevant experiments explore the interdependency between solid fuels and a methane-air premixed flame and some underlying issues, such as changes in burning velocity, flame temperature, gas emission, and metal oxide product. Uniquely, particle micro-explosion phenomena were observed in the Fe-Coal hybrid combustion. It conjectures that CO gas was trapped inside the thin porous iron oxide and led to the inception of iron carbonyl production. Combustible CO and iron carbonyl induced the inner combustion, leading to the particle torn or cracked. Ultimately, adding CO and metal organic frameworks (MOF) powder in a hybrid Fe flame was engaged to support the speculation of the proposed particle micro explosion mechanism.
