本研究主旨在於對鈣改質鐵系載氧體進行特性評估，並探討在不同燃料氣氛下以鈣改質鐵系載氧體進行化學迴路燃燒程序的反應行為與動力分析。關於鈣改質鐵系載氧體的特性評估，分別使用熱重分析儀、X-射線繞射分析儀、掃描電子顯微鏡進行探討並且評估載氧體的機械特性。由實驗結果可得知鈣改質鐵系載氧體有好的反應性及可再利用性，也發現改變氫氧化鈣的添加量會對載氧體的晶相造成影響，再者由表面分析可得知鈣改質鐵系載氧體相較原先鐵鋁載氧體較不易發生團聚及燒結現象。關於衝擊強度與磨耗試驗，則發現與原先鐵鋁載氧體相比經鈣改質之鐵系載氧體，其載氧體的衝擊硬度以及磨耗皆較差。
本研究亦探討鈣改質鐵系載氧體的反應行為與動力分析，研究中分別以氫氣以及一氧化碳做為燃料氣體於熱重分析儀中還原載氧體並探討不同氫氧化鈣的添加量以及不同反應溫度對載氧體的反應行為以及動力學參數之影響。在此載氧體得還原分成兩階段進行探討，分別為三氧化二鐵含還原到四氧化三鐵，再還原成氧化鐵。並利用熱重分析所得之實驗數據搭配反應動力模型進行計算，以一氧化碳對載氧體進行還原的實驗而言，第一階段還原為零級反應模型，而第二階還原以氫氧化鈣的添加量的多寡分別符合三級反應模型和一維擴散模型，且結果顯示反應速率常數會隨反應溫度增加而上升，於本研究中可利用活化能與碰撞頻率探討載氧氧的反應行為。

The aim of this study are characteristic evaluation of Ca-modified iron-based oxygen carriers by TGA, XRD, SEM-EDS and mechanical characteristic, and the reaction behavior and kinetic analysis of Ca-modified iron-based oxygen carriers with various fuels for chemical looping combustion process. TGA experiments showed that Ca-modified iron-based oxygen carriers had great reactivity and recyclability for continuous redox cycles by carbon monoxide or hydrogen reduction. Moreover, XRD results indicated that different crystalline phases were formed with adjusting Ca(OH)2 content. In addition, SEM image showed Fe-based oxygen carriers modified by Ca(OH)2 could help to resist the occurrence about agglomeration and sintering of oxygen carriers. With respect to the crush strength and attrition test, the experiment results exhibited that the crush strength and attrition of Ca-modified iron-based oxygen carrriers were poor compared with FA323-S1-s.
In this study, The reaction behavior and kinetic analysis of Ca-modified iron-based oxygen carriers were also discussed. The reduction kinetics of oxygen carriers were evaluated by different reaction temperature and Ca(OH)2 content were carried out in a TGA using CO and H2 as reducing gases. The reduction process was identified as two sequential stages including the reduction of Fe2O3-Fe3O4 and Fe3O4-FeO. Based on the reduction experiment of oxygen carrier reacted with carbon monoxide, the optimum model was zero-order model in the first stage reduction, and the optimum models were third-order model and 1-D diffusion model with Ca(OH)2 content in the second stage reduction. The experiment results indicated that the rate constant of four oxygen carriers was increasing with reaction temperature, and the reactivity of oxygen carrier can be evaluated by the activation energy and the collision frequency simultaneously.

Reference
Abad, A., Mattisson, T., Lyngfelt, A. and Johansson, M., “The Use of Iron Oxide as Oxygen Carrier in a Chemical-looping Reactor,” Fuel, Vol. 86, pp.1021-1035 (2007).
Adánez-Rubio, I., Gayán, P., Abad, A., García-Labiano, F., De Diego, L. F. and Adánez, J., “Kinetic Analysis of a Cu-based Oxygen Carrier: Relevance of Temperature and Oxygen Partial Pressure on Rreduction and Oxidation Reactions Rates in Chemical Looping with Oxygen Uncoupling (CLOU),” Chem. Eng. J., Vol. 256, pp. 69-84 (2014).
Adánez, J., Abad, A., Garcia-Labiano, F., Gayan, P. and de Diego, L.F., “Progress in Chemical-Looping Combustion and Reforming Technologies,” Prog. Energy Combust. Sci., Vol. 38, pp. 215-282 (2012).
Adánez, J., de Diego, L. F., García-Labiano, F., Gayán, P., and Abad, A., “Selection of Oxygen Carriers for Chemical-Looping Combustion,” Energy Fuels, Vol. 18, pp.371-377 (2004).
Berguerand, N. and Lyngfelt, A., “The Use of Petroleum Coke as Fuel in a 10 kWth Chemical-looping Combustor,” Int. J. Greenhouse Gas Control, Vol. 2, pp. 169-179 (2008).
Bost, N., Ammar, M. R., Bouchetou, M. L. and Poirier, J.,“The Catalytic Effect of Iron Oxides on the Formation of Nano-Carbon by the Boudouard Reaction in Refractories,” J. Eur. Ceram. Soc., Vol. 36, pp. 2133-2142 (2016).

Cabello, A., Abad, A., García-Labiano, F., Gayán, P., de Diego, L.F. and Adánez, J., “Kinetic Determination of a Highly Reactive Impregnated Fe2O3/Al2O3 Oxygen Carrier for Use in Gas-Fueled Chemical Looping Combustion,” Chem. Eng. J., Vol. 258, pp. 265-280 (2014).
Chiu, P. C., Ku, Y., Wu, Y. L., Wu, H. C., Kuo, Y. L. and Tseng, Y. H.,“Characterization and Evaluation of Prepared Fe2O3/Al2O3 Oxygen Carriers for Chemical Looping Process,” Aerosol Air Qual. Res., Vol. 14, pp. 981-990 (2014a).
Chiu, P. C., Ku, Y., Wu, H. C., Kuo, Y. L. and Tseng, Y. H.,“Chemical Looping Combustion of Polyurethane and Polypropylene in an Annular Dual-Tube Moving Bed Reactor with Iron-Based Oxygen Carrier,” Fuel, Vol. 135, pp. 146-152 (2014b).
Chiu, P. C., Ku, Y., Wu, H. C., Kuo, Y. L. and Tseng, Y. H.,“Spent Isopropanol Solution as Possible Liquid Fuel for Moving Bed Reactor in Chemical Looping Combustion,” Energy Fuels, Vol. 28, pp. 657-665 (2013).
Chen, L., Bao, J., Kong, L., Combs, M., Nikolic, H. S. and Fan, Z.,“The Direct Solid-Solid Reaction between Coal Char and Iron-Based Oxygen Carrier and Its Contribution to Solid-Fueled Chemical Looping Combustion,” Appl. Energy, Vol. 184, pp. 9-18 (2016).
Cho, P., Mattisson, T. and Lyngfelt, A., “Comparison of Iron-, Nickel-, Copper- and Manganese-Based Oxygen Carriers for Chemical-Looping Combustion,” Fuel, Vol. 83, pp. 1215-1225 (2004).
Fan, L. S., “Chemical Looping Systems for Fossil Energy Conversions,” New Jersey: John Wiley & Sons, Inc. (2010).
Fennell, P. and Anthony, B., “Calcium and Chemical Looping Technology for Power Generation and Carbon Dioxide (CO2) Capture,” United Kingdom: Woodhead Publishing, Inc. (2016).
Ge, H., Shen, L., Gu, H. and Jiang, S., “Effect of Co-Precipitation and Impregnation on K-decorated Fe2O3/Al2O3 Oxygen Carrier in Chemical Looping Combustion of Bituminous Coal,” Chem. Eng. J., Vol, 262, pp. 1065-1076 (2015).
Gu, H., Shen, L., Zhong, Z., Niu, X., Liu, W., Ge, H., Jiang, S. and Wang, L., “Cement/CaO-Modified Iron Ore as Oxygen Carrier for Chemical Looping Combustion of Coal,” Appl. Energy, Vol, 157, pp. 314-322 (2015).
Hua, X., Wang, W. and Wang, F., “Performance and Kinetics of Iron-Based Oxygen Carriers Reduced by Carbon Monoxide for Chemical Looping Combustion,” Front. Environ. Sci. Eng., Vol. 9, pp. 1130-1138 (2015).
Huang, Z., Zhang, Y., Fu, J., Yu, L., Chen, M., Liu, S., He, F., Chen, D., Wei, G., Zhao, K., Zheng, A., Zhao, Z. and Li, H., “Chemical Looping Gasification of Biomass Char Using Iron Ore as an Oxygen Carrier,” Int. J. Hydrogen Energy, Vol, 41, pp. 17871-17883 (2016).
Johansson, M., Mattisson, T. and Lyngfelt, A., “Comparison of Oxygen Carriers for Chemical-Looping Combustion,” Therm. Sci., Vol. 10, pp. 93-107 (2006).
Johansson, M., Mattisson, T. and Lyngfelt, A., “Investigation of Fe2O3 with MgAl2O4 for Chemical-Looping Combustion,” Ind. Eng. Chem. Res., Vol. 43, pp. 6978-6987 (2004).
Khawam, A. and Flanagan, D. R., “Basics and Applications of Solid-State Kinetics: A Pharmaceutical Perspective,” J. Pharm. Sci., Vol. 95, pp. 472-498 (2006).
Khawam, A. and Flanagan, D. R., “Solid-State Kinetic Models: Basics and Mathematical Fundamentals,” J. Phys. Chem. B, Vol. 110, pp. 17315-17328 (2006).
Ku, Y., Wu, H. C., Chiu, P. C., Tseng, Y. H. and Kuo, Y. L.,“Methane Combustion by Moving Bed Fuel Reactor with Fe2O3/Al2O3 Oxygen Carriers,” Appl. Energy, Vol. 113, pp. 1909-1915 (2014).
Kuo, Y. L., Hsu, W. M., Chiu, P. C., Tseng, Y. H. and Ku, Y., “Assessment of Redox Behavior of Nickel Ferrite as Oxygen Carriers for Chemical Looping Process,” Ceram. Int., Vol. 39, pp. 5459-5465 (2013).
Kuo, Y. L., Huang, W. C., Tseng, Y. H., Chang, S. H. and Ku, Y., “Electric Arc Furnace Dust as an Alternative Low-Cost Oxygen Carrier for Chemical Looping Combustion,” J. Hazard. Mater., Vol. 342, pp. 297-305 (2018).
Linderholm, C., Schmitz, M., Knutsson, P., Källén, M. and Lyngfelt, A., “Use of Low-volatile Solid Fuels in a 100 kW Chemical-Looping Combustor,” Energy Fuels, Vol. 28, pp. 5942-5952 (2014).
Liu, W., Dennis, J. S. and Scott, S. A., “The Effect of Addition of ZrO2 to Fe2O3 for Hydrogen Production by Chemical Looping,” Ind. Eng. Chem. Res., Vol. 51, pp. 16597-16609 (2012).
Lyngfelt, A., “Chemical-Looping Combustion of Solid fuels – Status of Development,” Appl. Energy, Vol, 113, pp. 1869-1873 (2014).
Markström, P., Linderholm, C. and Lyngfelt, A., “Operation of a 100 kW Chemical-Looping Combustor with Mexican Petroleum Coke and Cerrejón Coal,” Appl. Energy, Vol. 113, pp. 1830-1835 (2014).
Mattisson, T., Johansson, M. and Lyngfelt, A., “Multicycle Reduction and Oxidation of Different Types of Iron Oxide Particles-Application to Chemical-Looping Combustion,” Energy Fuels, Vol. 18, pp. 628-637 (2004).
Mei, D., Abad, A., Zhao, H., Adánez, J. and Zheng, C., “On a Highly Reactive Fe2O3/Al2O3 Oxygen Carrier for In Situ Gasification Chemical Looping Combustion,” Energy Fuels, Vol. 28, pp. 7043-7052 (2014)
Monazam, E. M., Breault, R. W. and Siriwardane, R., “Reduction of Hematite (Fe2O3) to Wüstite (FeO) by Carbon Monoxide (CO) for Chemical Looping Combustion,” Chem. Eng. J., Vol. 242, pp. 204-210 (2014).
Pans, M. A., Gayán, P., de Diego, L. F., García-Labiano, F., Abad, A. and Adánez, J., “Performance of a low-cost iron ore as an oxygen carrier for Chemical Looping Combustion of gaseous fuels,” Chem. Eng. Res. Des., Vol. 93, pp. 736-746 (2015).
Pineau, A., Kanari, N. and Gaballah, I., “Kinetics of reduction of iron oxides by H2 Part I: Low temperature reduction of hematite,” Thermochim. Acta, Vol. 447, pp. 89-1000 (2006).
Qin, L., Majumder, A., Fan, J. A., Kopechek, D. and Fan, L. S., “Evolution of Nanoscale Morphology in Single and Binary Metal Oxide Microparticles during Reduction and Oxidation Processes,” J. Mater. Chem. A, Vol. 2, pp. 17511-17520 (2014).
Song, T., Shen, L., Guo, W., Chen, D. and Xiao, J., “Enhanced Reaction Performance with Hematite/Ca2Al2SiO7 Oxygen Carrier in Chemical Looping Combustion of Coal,” Ind. Eng. Chem. Res., Vol. 52, pp. 9573-9585 (2013).
Su, M., Ma, J., Tian, X. and Zhao, A., “Reduction Kinetics of Hematite as Oxygen Carrier in Chemical Looping Combustion,” Fuel Process. Technol., Vol. 155, pp. 160-167 (2017).
Tseng, Y. H., Ma, J. L., Chiu, P. C., Kuo, Y. L. and Ku, Y., “Preparation of Composite Nickel–Iron Oxide as Highly Reactive Oxygen Carrier for Chemical-Looping Combustion Process,” J. Taiwan Inst. Chem. Eng., Vol. 45, pp. 174-179 (2014).
Wang, J. and Zhao, H., “Application of CaO-Decorated Iron Ore for Inhibiting Chlorobenzene during In Situ Gasification Chemical Looping Combustion of Plastic Waste,” Energy Fuels, Vol. 30, pp. 5999-6008 (2016a).
Wang, J. and Zhao, H., “Chemical Looping Dechlorination through Adsorbent-Decorated Fe2O3/Al2O3 Oxygen Carriers,” Combust. Flame, Vol. 162, pp. 3503-3515 (2015).
Wang, J. and Zhao, H., “Evaluation of CaO-Decorated Fe2O3/Al2O3 as an Oxygen Carrier for In-Situ Gasification Chemical Looping Combustion of Plastic Wastes,” Fuel, Vol. 165, pp. 235-243 (2016b).
Wu, H. C., Ku, Y., Tsai, H. H., Kuo, Y. L. and Tseng, Y. H.,“Rice Husk as Solid Fuel for Chemical Looping Combustion in an Annular Dual-Tube Moving Bed Reactor,” Chem. Eng. J., Vol. 280, pp. 82-89 (2015).

Yu, Z., Li, C., Jing, X., Zhang, Q., Wang, Z., Fang, Y. and Huang, J., “Catalytic Chemical Looping Combustion of Carbon with an Iron-Based Oxygen Carrier Modified by K2CO3: Catalytic Mechanism and Multicycle Tests,” Fuel Process. Technol., Vol, 135, pp. 119-124 (2015).
Zafar, Q., Abad, A., Mattisson, T. and Gevert, B., “Reaction Kinetics of Freeze-Granulated NiO/MgAl2O4 Oxygen Carrier Particles for Chemical-Looping Combustion,” Energy Fuels, Vol. 21, pp. 610-618 (2007).
Zhang, Y., Doroodchi, E. and Moghtaderi, B., “Chemical Looping Combustion of Ultra Low Concentration of Methane with Fe2O3/Al2O3 and CuO/SiO2,” Appl. Energy, Vol. 113, pp. 1916-1923 (2014).
Zhang, Y. and Zheng, Y., “Co-Gasification of Coal and Biomass in a Fixed Bed Reactor with Separate and Mixed Bed Configurations,” Fuel, Vol. 183, pp. 132-138 (2016).