Analysis of Reactivity of a CuO-Based Oxygen Carrier for Chemical Looping Combustion of Coal

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• 作者：Shuzhong Wang ; Ming Luo ; Guoxian Wang ; Longfei Wang ; Mingming Lv
• 刊名：Energy & Fuels
• 出版年：2012
• 出版时间：June 21, 2012
• 年：2012
• 卷：26
• 期：6
• 页码：3275-3283
• 全文大小：581K
• 年卷期：v.26,no.6(June 21, 2012)
• ISSN：1520-5029

文摘

Chemical looping combustion (CLC) of coal was conducted with 12 CuO-based oxygen carriers supported on SiO₂, Al₂O₃, TiO₂, and ZrO₂ prepared by mechanical mixing. The influence of an inert support and the effect of particle size on the reactivity of CuO-based oxygen carrier particles were studied. Five mixed oxide oxygen carriers composed of different amounts of CuO and Fe₂O₃ on TiO₂ were prepared to study the synergistic effect between two active metallic oxides. It was found that CuO-based oxygen carriers showed high reactivity in redox reactions. The onset temperature of the reduction reaction decreased when TiO₂ was added as an inert support. The particles of CuXTi950 showed the highest reactivity to convert the coal. Although the smaller particle size of the oxygen carrier can enhance the coal conversion, it also makes it more difficult in the separation of the oxygen carrier from fly ash and unburned carbon. For mixed oxygen carriers, the synergistic effect between different active oxides was observed. From a reactivity and an energy-balance perspective, particles of CuO鈥揊e₂O₃/TiO₂ mixed oxide oxygen carriers are suitable for use in CLC of coal. The X-ray diffractometer (XRD) and scanning electron microscope (SEM) were used for the characterization of the fresh and used oxygen carriers. Results support that direct CLC of coal is promising when CuO-based oxygen carriers are used at low temperatures.