Dechlorination Performance of Chemical Looping Conversion Using Red Mud as an Oxygen Carrier
Dechlorination Performance of Chemical Looping Conversion Using Red Mud as an Oxygen Carrier
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DOI：
10.1021/acs.energyfuels.2c00948
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发表时间：
2022-07
期刊：
影响因子：
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通讯作者：
Hongming Jiang;C. Li;Luyou Chen;Shuchang Yan;Yan Lin;Zengli Zhao;Zhen Huang;Shujia Wang;Hongyu Huang;Hai-bin Li
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文献类型：
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作者：
Hongming Jiang;C. Li;Luyou Chen;Shuchang Yan;Yan Lin;Zengli Zhao;Zhen Huang;Shujia Wang;Hongyu Huang;Hai-bin Li
化学循环(CL)转化是一种具有CO2捕集和污染控制能力的燃料热利用技术。在处理含氯有机固体废物的过程中，会产生大量的HCl以及剧毒的多氯二苯并对二恶英和多氯二苯并呋喃，从而造成严重的设备腐蚀和环境危害。氧化铝行业生产的赤泥(RM)是一种潜在的廉价氧载体(OC)。本文选取了三种不同类型的有机碳，研究了有机碳制备和脱氯过程中含钠、含钙化合物的演化和变化。探讨了不同反应条件下RM OCS的脱氯机理和性能。结果表明，在较高的反应温度下，富Na和富Na/Ca的RMOCS具有良好的脱氯性能。具有脱氯活性的RMOC组分包括可溶碱形式的Na(例如，NaOH)、Na2Ti3O7和Na6Al4Si4O17，以及CaO、Ca2SiO4和CaTiO3形式的Ca，而NaAlSiO4、Na1.15(Al1.15Si0.85O4)和Ca2Al2SiO7是惰性的。水蒸气和高温的存在抑制了RM OCS的脱氯性能。在使用RMOCS的脱氯过程中，HCl首先与OC表面的活性元素发生快速反应，脱氯效率很高。随着表面活性元素的饱和，反应进入HCl扩散控制阶段，此时合适的OC粒径和气体停留时间有利于提高脱氯效率。
Chemical looping (CL) conversion is a fuel heat utilization technology with CO2capture and pollution control capability. During the treatment of Cl-containing organic solid waste, a large amount of HCl is generated, along with highly toxic polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans, thereby resulting in serious equipment corrosion and environmental harm. Red mud (RM) produced by the alumina industry is a potential cheap oxygen carrier (OC) within situdechlorination capability. In this paper, three types of RM are selected to study the evolution and varieties of Na- and Ca-containing compounds in the process of OC preparation and dechlorination. The dechlorination mechanisms and performances of the RM OCs under various reaction conditions are discussed. The results verify that the Na- and Na/Ca-rich RM OCs exhibit good dechlorination performances at a high reaction temperature. The RM OC components with dechlorination activity include Na in the form of soluble alkali (e.g., NaOH), Na2Ti3O7, and Na6Al4Si4O17, along with Ca in the form of CaO, Ca2SiO4, and CaTiO3, whereas NaAlSiO4, Na1.15(Al1.15Si0.85O4), and Ca2Al2SiO7are inert. The dechlorination performances of the RM OCs are inhibited by the presence of water vapor and high temperature. In the dechlorination process using RM OCs, HCl first reacts rapidly with active elements on the surface of the OC with high dechlorination efficiency. With the saturation of surface-active elements, the reaction enters the HCl diffusion control stage, when the appropriate particle size of the OC and the gas residence time are helpful for improving the dechlorination efficiency.