本研究主要利用Fe2TiO5做為化學迴圈中之載氧體，分析該載氧體在高溫環境下之攜氧量及氧化-還原過程中不同階段之晶相變化，並探討Fe2TiO5在不同球磨時間、反應溫度及燒結溫度對載氧體之反應性及再循環能力之影響，研究中分別以氫氣和合成氣 (氫氣和一氧化碳) 做為燃料氣體還原載氧體，探討載氧體於熱重分析儀及固定床反應系統中之氧化還原性，並藉由X射線繞射光譜儀、場發式電子顯微鏡及比表面積測定儀分析材料之結晶結構、表面型態、粒徑分佈、孔隙結構及比表面積等。實驗結果顯示，Fe2TiO5在900 oC下與燃料氣體進行還原反應時之熱重損失20 %，其晶相依不同的還原階段會依序形成Fe2TiO4，FeTiO3和Fe/TiO2；經還原的載氧體在與通入空氣氧化反應後則會形成Fe2O3、TiO2和微量的Fe2TiO5。Fe2TiO5粉體經過2小時球磨後將粉體製備成錠材，經900 oC高溫燒結後，維持900 oC反應溫度，反覆對Fe2TiO5進行還原-氧化操作後發現，當氧化-還原經過30次循環之後，Fe2TiO5材料表面會開始出現明顯的孔洞生成及裂紋，比表面積亦隨之增大，伴隨發現有部分團聚的現象，但不影響Fe2TiO5之反應性和再循環能力，並仍然能夠高溫環境下穩定進行1000次以上的氧化-還原操作。在固定床反應系統中，亦藉由通入水蒸氣氧化Fe/TiO2，同時使水蒸氣還原產氫，每克Fe2TiO5在900 oC的操作溫度下，每30分能夠穩定的達到8.11 mmol的產氫量。

Applicability of Fe2TiO5 as oxygen carrier for chemical looping process (CLP) was investigated in this study. The oxygen transfer capacity and crystallization behavior of Fe2TiO5 were analyzed during the oxidization-reduction (redox) reaction. Reactivity and recyclability of oxygen carrier operated at various reaction temperatures were also estimated by thermogravimetric analyzer (TGA) and fixed bed reactor system (FBR) with inlet stream of H2 and syngas (H2 and CO) and the oxygen carrier fabricated under various milling durations and sintering temperatures. The crystal structure, surface formation, particle size distribution, pore structure and surface area of oxygen carrier were analyzed by x-ray diffraction analysis (XRD), field-emission scanning electron microscope analysis (FE-SEM) and specific surface area analyzer (BET). Experimental results indicated that the weight loss of Fe2TiO5 was ca. 20 wt% at reaction temperature of 900 oC for experiments conducted with inlet stream of syngas. The crystal phase of Fe2TiO5 was reduced to lower oxidation states, i.e. Fe2TiO4, FeTiO3, and Fe/TiO2 during the reduction reaction of oxygen carrier, and later oxidized to mixture of TiO2, Fe2O3 and trace of Fe2TiO5 phase with air. The powder of Fe2TiO5 was milled for 2 hours then formed into pellet and subsequently sintered at 900 oC before underwent the oxidization-reduction reaction continuously at 900 oC. Higher porosity and surface area and the agglomeration of oxygen carrier particles were observed with increasing the redox cycle. Stable quantity of reactivity indicated that Fe2TiO5 not only has superior reactivity but also high recyclability stability for chemical looping process over 1000 redox cycle at high operating temperature. Oxidization of oxygen carrier (Fe/TiO2) with steam in fixed bed reactor system at 900 oC generated 8.11 mmol/g hydrogen gas every 30 mins.

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