通过对克努森数的计算，判别了SO2气体在煅烧后石灰石颗粒内部的扩散形式，由于分子自由程远大于孔径，故努森扩散在孔内传质过程中起控制作用。通过对扩散系数与本征动力学反应速度系数的比较，认为SO2气体通过固体产物层的扩散，对固硫反应起控制作用。文中还讨论了温度、NaCl催化、增湿活化等因素对孔结构和扩散的影响。 By calculating the Knudsen number, the diffusion form of SO2 gas inside the calcined limestone particles is discriminated. Since the free path of the molecule is much larger than the pore diameter, the diffusion of Knudsen diffusion in the pores plays a controlling role. By comparing the diffusion coefficient with the intrinsic kinetic reaction velocity coefficient, it is considered that the diffusion of SO2 gas through the solid product layer can control the sulfur fixation reaction. The paper also discussed the influence of temperature, NaCl catalysis, humidification activation and other factors on pore structure and diffusion.