Synthesis of CaO-based sorbents through incorporation of alumina/aluminate and their CO₂ capture performance

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• 作者：Zhiming Zhou ; ^{zmzhou@ecust.edu.cn} ; Yang Qi ; Miaomiao Xie ; Zhenmin Cheng ; Weikang Yuan
• 关键词：CaO-based sorbent ; CO2 capture ; Absorption ; Morphology ; Stability ; Environment
• 刊名：Chemical Engineering Science
• 出版年：2012
• 期刊代码：18_00092509
• 类别：ce
• 出版时间：28 May, 2012
• 卷：74
• 期：Complete
• 页码：172-180
• 文件大小：1138 K

摘要

CaO-based CO₂ sorbents derived from various calcium and aluminum precursors were prepared by a wet mixing method and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and N₂ adsorption-desorption techniques. The as-prepared sorbents consisted of active CaO and inert support materials that could be Al₂O₃, Ca₁₂Al₁₄O₃₃ or Ca₉Al₆O₁₈, depending on calcium and aluminum precursors used during the preparation process. A formation mechanism for the inert support materials was proposed. Compared to pure CaO, most of the synthetic CaO-based sorbents showed much higher CO₂ capture capability and stability over multiple carbonation/calcination cycles, which was ascribed to the relatively high specific surface area of the sorbents, the bimodal pore-size distribution with a fair number of small pores, and the inert support material that can effectively prevent or delay sintering of CaO particles. Among these synthetic sorbents the CaO-Ca₉Al₆O₁₈ sorbent with a CaO content of 80 wt%(weight fraction) derived from calcium citrate and aluminum nitrate exhibited the best performance for CO₂ capture, and can be expected to be applied in the sorption-enhanced steam methane reforming process.