本研究係以兩種鐵礦石AB(Australia B.H.P)與BC(Brazil CVRD)作為載氧體，應用於化學迴圈燃燒程序中，並以金屬改質(K、Na、Mg、Ca)載氧體，針對6種實驗變因(反應溫度、還原時間、金屬種類、金屬含量、燃料種類以及載氧體與燃料比)進行探討，期望提升二氧化碳的純度與產率，以做為後續封存與再利用之應用。
首先，由熱重分析儀(Thermogravimetric analyzer, TGA)初步進行反應性測試，探討反應溫度與金屬種類的影響，實驗結果顯示，提高反應溫度，有助於提升天然鐵礦石的氧化還原速率，而金屬改質的載氧體，除Mg之外其轉化速率皆有明顯的提升，特別是AB-K10與BC-Na10的反應性最佳。在流體化床反應器(Fluidized-bed reactor, FBR)系統，藉由理論計算其最小流體化速度及冷模的測試下，使用CO為燃料，使載氧體在流體化的狀態，進行5次氧化還原迴圈測試，亦顯示金屬改質的載氧體皆能有效的提升反應性，使用AB-K10、AB-Ca10、BC-Na10與BC-Ca10皆可獲得大於90%的CO2產率。接著測試其金屬含量的影響，將還原相態控制在Fe2O3與Fe3O4之間，使用AB-K5~15與AB-Ca15，皆能達到99%的純度與產率，進一步考慮應用成本及操作可行性，選用AB-K10(操作成本2.9 USD/ton•h)作為多次迴圈測試的載氧體。在連續操作50迴圈後，載氧體仍維持良好的反應性，且沒有明顯的聚集和去流體化的現象發生。然而，AB-K10應用於CH4燃料時，雖然其反應性較差，但在長時間還原時，添加水氣能有效抑制積碳現象，且隨著載氧體與燃料比值下降時，反應性也會有提高的現象，值得進一步探討。本實驗結果顯示，AB-K10具有化學迴圈商業化潛力。

In this work, two kinds of iron ore (AB and BC) were modified via wet impregnation method with using variant metal salts as effective oxygen carriers for chemical-looping combustion (CLC) process. Six experimental parameters, reaction temperature, reduction time, kind of metal, metal content, kind of fuel and ratio of oxygen carrier to fuel, were investigated for the improvement in the purity and yield of carbon dioxide, which plays an important role in the ultilization and stroage of CO2.
First, the effects of reaction temperature and the metal additives of iron ore on the redox activity were evaluated in a TGA system. The results showed the good redox rate can be increased with the increase in reaction temperature and using metal additives, except Mg. AB-K10 and BC-Na10 exhibited the best reactivity. In further FBR system, the minimum fluidization velocity(2 L/min at 25℃) was obtained by theoretical calculation and the cold model test. Then, five cycles of CLC reaction with using CO as fuel were carried out to test the activities of oxygen carriers. The results the purity and yield of CO2 were higher than 90% with using AB-K10, AB-Ca10, BC-Na10 and BC-Ca10. The highest purity and tield of crbon dioxide can be achieved with using AB-K5, AB-K10, AB-K15 and AB-Ca15, respectively. On the basis of cost and life time of oxygen carrier, we choose AB-K10 with the operation cost of 2.9 USD/ton•h for multi-cycle test. After 50 CLC cycles, the result showed AB-K10 maintains good reactivity, without obvious aggregation and defluidized phenomenon. However, AB-K10 showed the lower reactivity as the methane is used as fuel. In this system, the increase in time and partial pressure of CH4 and improve the purity and yield of carbon dioxide. In addition, the carbon deposition on oxygen carrier can be avoided in the presence of steam. From the above discussion, AB-K10 is a practical oxygen carrier for chemical looping combustion process.

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