Numerical study of pore structure effect on SO2–CaO reactions

The effect of varying pore structures on the kinetics of SO2–CaO reactions is not fully understood in the previous studies. Combining fractal pore model, gas molecular movement model and two-stage reaction model, a new desulfurization model is established in this paper. Fractal pore model is used to simulate CaO particle and gas molecular movement model is used to simulate gas diffusion in pores. Fractal dimension is used to characterize complexity of pore structure instead of tortuosity factor. It is found that the reaction is significantly affected by pore structures. A modulus ϕ is introduced to characterize the relationship between varying pore structures and apparent reaction parameters. And this relationship is verified by thermo-gravimetric analysis (TGA) data. Comparing to the previous models, the effect of varying pore structure on the kinetics of the reaction is described more accurately by the desulfurization model.

Graphical AbstractThis paper created three-dimensional fractal pore models with 100 × 100 × 100 cubic grids. A typical fractal pore model is shown in Fig. 1 where the black cubes are solid CaO grids and the white cubes are pore grids. Visually, the contour shapes of the fractal pores are similar to real pores.Figure optionsDownload full-size imageDownload as PowerPoint slide