煤焦O_2/CO_2燃烧反应性及结构演化的分子模拟研究

Coal Char Reactivity and Micro-Structure Influences in O_2/CO_2 Combustion Using Simplified Atomistic Simulation

本文通过自编程序Fringe3D和Vol3D构建了具备一定孔隙结构特征的大尺度煤焦分子模型（碳原子数40000）,通过简化的分子模拟方法编程实现了煤焦O2/CO2燃烧微观反应过程的模拟。模拟结果表明：随着燃烧反应的进行,煤焦结构逐渐＂缩核＂变小,而煤焦结构尺寸的变化主要发生在燃烧后期。随着碳转化率的增大,低活性碳原子的数量逐渐减少,而高活性碳原子的数量先增加后减少。与空气燃烧相比,煤焦在O2/CO2气氛下的燃烧过程明显延迟,而煤焦比表面积的改变对煤焦反应性的变化有紧密关联。

Here,a large-scale（40000 atoms） atomistic coal char representation（with a measure of control over structural and physical properties） was constructed using in-house scripts Pringe3 D and Vol3 D.A simplified inexpensive simulation approach proposed in our earlier work was employed to compare the char combustion reactivity and char micro-structure evolution under O2/CO2 conditions.Simulation results indicate that compared with air combustion,char combustion in O2/CO2 atmosphere is obviously prolonged.The present simulation process captures the char reactivity disparities between different combustion conditions.As char is combusted,lower reactive carbon decreases while higher reactive carbon first increases than decreases.In addition,accessible surface area of char has a close relevance with its combustion reactivity.