CuO修饰的赤泥载氧体废弃活性炭化学链燃烧

Chemical looping combustion of waste activated carbon with oxygen carrier of CuO-modified red mud

以拜耳法赤泥为基体,采用浸渍法制备了CuO修饰的赤泥载氧体(Cu0.5RM1、Cu1RM1)。利用SEM-EDS mapping、XRD对其进行物化表征,并在高温流化床反应器及热重分析仪中考察了赤泥载氧体的废弃活性炭化学链燃烧特性。结果表明,浸渍法可准确制备定量CuO修饰的赤泥载氧体;相比于纯赤泥载氧体,CuO修饰的赤泥载氧体具有化学链燃烧载氧体与化学链氧解耦燃烧载氧体的双重特性,能够加快碳转化速率,有效提高出口气体中CO_2浓度;Cu1RM1反应活性较高,875℃为其较优的反应温度,此时t95为28min,出口气体中CO_2浓度为92.9%(体积分数),燃烧效率达93.0%。10次循环实验表明Cu1RM1载氧体具有相对稳定的循环反应特性。

CuO-modified red mud oxygen carriers（Cu0.5 RM1, Cu1 RM1） were prepared by impregnation method and characterized by SEM-EDS mapping and XRD. The reactivity of red mud oxygen carrier in chemical looping combustion（CLC）, with waste activated carbon（WAC） as raw material, was evaluated in a high-temperature bench fluidized-bed reactor and thermogravimetric analyzer（TGA）. The results of SEM-EDS mapping showed that impregnation method was a desirable approach for preparing quantitative CuO-modified red mud oxygen carriers. CuO-modified red mud oxygen carriers were demonstrated to act as both CLC oxygen carrier and chemical looping with oxygen uncoupling oxygen carrier. Furthermore, WAC conversion rate and CO2 concentration were significantly enhanced in comparison to pure red mud oxygen carriers. Additionally, it was found that Cu1 RM1, due to the higher CuO loading, performed higher reactivity than Cu0.5 RM1. Under the optimum temperature of 875℃, the CO2 average concentration of 92.9%, the combustion efficiency of 93.0% and the residence time（t95） of 28 min were achieved. Moreover, Cu1 RM1 had a good stability during the 10 redox tests.