Textural properties of iron oxide sorbents and its effects on the performance of desulfurization

Abstract：It is of great significance to study the effect of texture on the performance of the sor- bent for developing hot gas desulfurizer with high efficiency and good stability. Polystyrene （PS） microspheres with different size were synthesized by controlling the experimental conditions. Using the as-synthesized PS as the pore-forming materials and the red-mud from steel factory as the activate component, three iron oxide sorbents with different texture including pore diameter, pore volume and fractal dimension were prepared for the hot gas desulfurization. The microstructure of PS microspheres was analyzed by SEM, while the texture of fresh sor- bents was characterized by mercury porosimetry. The effects of texture on the performance of the sorbent as well as the sulfidation kinetics were investigated by thermogravimetric analysis. A modified grain model was used to simulate the desulfurization reaction proceed. The results show that different PS microspheres size produced different sorbents texture respectively. The activation energies of chemical reactions of three sorbents were 22.1, 20.1 and 25.7 kJ/mol, while the diffusion activation energies were 49.6, 26.0 and 19.4 kJ/mol, respectively. This shows that the different diffusion resistances caused the sorbent texture to have different effects on the sorbent performance during desulfurization.