中文摘要：

为研究热解时煤粉颗粒孔隙结构的变化，采用随机行走的方法生成煤粉颗粒的孔隙结构，采用碎片化和扩散煤热解模型描述热解时的化学反应，基于分子运动论描述气体在分形孔隙中的扩散，构建了一个描述孔隙结构变化的数学模型．通过对模型计算结果的拟合，得到描述孔隙结构变化的微分方程组，并用沉降炉热解实验对方程组进行了验证．应用该微分方程组研究了加热速率对孔隙结构变化的影响，结果表明，在膨胀阶段和收缩阶段，4个孔隙结构参数的变化速率都存在一个峰值．随着加热速率的提高，煤焦的膨胀率、比表面积和分形维数先增大后减小，而煤焦的孔隙率是一直增大的．

英文摘要：

A numerical model was developed to investigate the variation of pore structure of coal particle duringpyrolysis.In the model,the pore structure of coal particle was generated by the method of random walk,thechemical reactions were modeled by the fragmentation and diffusion(FD)pyrolysis model and the gas diffusion inthe pore structure was modeled by the kinetic theory of gases.By curve fitting with the model results,four differentialequations were obtained to characterize the variation of pore structure of coal particle and validated by theexperimental data in a drop-tube furnace.The effect of heating rate on the variation of pore structure was then investigatedwith the differential equations.The simulation results show that,for the four parameters of pore structureof coal particle,there exist the peak values of variation rates during the swelling and contraction stages.Asheating rate increases,char porosity increases while the swelling ratio,specific surface area and fractal dimensionof char first increase and then decrease.