Cu-Mn复合载氧体释氧反应性及动力学研究

Oxygen release reactivity and kinetics of Cu-Mn composite oxygen carriers

载氧体作为化学链转换技术的核心与关键,其性能决定了反应过程的经济性和稳定性。采用石墨成孔浸渍法制备了4种不同含量Cu修饰的Cu-Mn复合载氧体,对其进行了表征和抗磨损性能实验。在热重分析仪上研究了载氧体的释氧特性和循环反应特性,并采用Model-free method分析了载氧体的释氧动力学特性。结果表明:载氧体制备过程中活性组分CuO和Mn2O3并未与惰性载体MgO发生化学反应;Cu修饰对载氧体具有拓孔作用,可以显著提高载氧体比表面积和总释氧量,降低释氧所需温度,缩短释氧时间,降低释氧活化能;但随着Cu含量的增加,载氧体抗烧结性能和抗磨损性能逐渐降低,且随着循环次数增加,载氧体循环反应性能降低。

As the core and key of chemical looping conversion technology, the performance of oxygen carrier determines the economy and stability of the reaction process. Four kinds of Cu-Mn composite oxygen carriers with different content of Cu were prepared by graphite pore forming impregnation method, and their surface features and wear resistance were analyzed. The oxygen release characteristics and cyclic reaction characteristics of oxygen carriers were studied by thermogravimetric analyzer, and the oxygen release kinetics characteristics of oxygen carriers were analyzed with Model-free method. The results suggest that CuO and Mn2O3 do not react with MgO during the preparation process. Cu modification can significantly increase the specific surface area and total oxygen release of the oxygen carrier, reduce the oxygen release temperature, shorten the oxygen release time and reduce the oxygen release activation energy. However, the sintering resistance and wear resistance of the oxygen carrier decrease gradually as the Cu content increase, and the cycling reaction performance of the oxygen carrier decreases as the cycling times increases.