CO化学链燃烧过程中铁基载氧体结构变化及其影响作用研究

Rational modification of oxygen carrier and control strategy optimization of operating mode for chemical looping combustion (CLC)system have been restricted by the insufficiency of investigation about the structural transformation of oxygen carrier and its effect on the reaction during CLC. This study will focus on mechanism of CO combustion reaction to different active sites on the outer and inner surface of oxygen carrier using density functional theory (DFT) calculations,combustion experiments, and in situ spectroscopy. According to the surface reactions, further theoretical calculations and experimental characterizations will be performed to detect the structural evolution processes of oxygen carrier and reaction mechanism influenced by the change of structure and properties. Then, multi-field coupling interaction system will be simulated for modeling and theoretical calculations, and CLC experiments will also be performed under dynamic field and thermal field, for investigating the structure of oxygen carrier, combustion state, and response characteristics to the reaction system in depth. These works will reveal the mechanism of structural transformation and its effect during CLC of CO, and qualitatively and quantitatively express the essential correlation of oxygen carrier-thermodynamic cycling condition-combustion characteristics, providing fundamental theory for studying the rational modification of oxygen carrier and operating mode of CLC.

载氧体在化学链燃烧过程中结构的变化机理及其对燃烧反应影响研究的缺乏，制约了载氧体的合理改性和化学链燃烧工况控制策略的优化。本项目基于密度泛函理论计算和燃烧实验，结合原位谱学表征研究CO在铁基载氧体外表面尤其是孔道内表面不同位点的燃烧反应机理；在表面反应的基础上，进一步通过理论计算和实验表征分析CO燃烧反应过程中载氧体结构的演变过程，载氧体结构和性质的变化对CO反应过程和产物分布的影响规律；定义多场耦合作用体系，建模进行理论模拟计算，并在热力/动力场耦合作用下进行化学链燃烧实验，对不同时空点的载氧体结构及燃烧产物、燃烧状态和反应系统响应特性进行深入研究。揭示CO化学链燃烧过程中铁基载氧体结构变化及其影响作用机理，定性和定量表达载氧体-热动力循环条件-燃烧特性的内在关联，为载氧体的合理改性研究和化学链燃烧工况控制研究提供基础理论支撑。

项目采用理论分析和实验研究相结合的方法，研究了铁基载氧体作用下CO化学链燃烧的反应机理；化学链燃烧过程中CO不断还原铁基载氧体表面的结构渐变过程，载氧体物化特性渐变规律及其对CO化学链燃烧的影响作用。主要开展的工作包括：（1）构建铁基载氧体表面模型，研究铁基载氧体表面电子结构特性及其与CO反应机理，揭示CO在不同表面不同位点吸附和氧化反应机制；（2）基于理想的铁基载氧体表面，研究铁基载氧体表面不断被还原形成一系列还原表面的结构渐变规律，及其对CO氧化及积碳形成的影响规律；（3）考虑化学链燃烧体系惰性元素在载氧体表面沉积，而致变的载氧体结构及其对CO化学链燃烧导致积碳形成的影响规律；（4）研究不同反应条件下铁基载氧体与CO化学链燃烧过程构-效关系及动力学模型分析。本课题揭示CO化学链燃烧过程中铁基载氧体结构变化及其影响作用机理，定性和定量表达与CO化学链燃烧过程的构-效变化规律，为载氧体的合理改性研究和化学链燃烧工况控制提供基础数据。