氧化铁脱硫剂的织构及其对脱硫性能的影响

了解织构特性对脱硫剂脱硫性能的影响,对开发高效稳定的高温煤气脱硫剂至关重要,通过改变实验条件,合成了不同粒径的聚苯乙烯(PS)微球,以此为造孔剂,以钢厂赤泥为活性组分,制备出3种具有不同织构特性(孔径、孔容及分形维数等)的氧化铁脱硫剂.采用电镜对合成的PS微球进行分析,用压汞法对脱硫剂的织构进行表征,采用热重法考察织构对脱硫剂性能的影响,研究了脱硫动力学行为,以等效粒子模型模拟脱硫反应历程.结果表明,以不同粒径的PS微球为造孔剂,可制备出织构不同的脱硫剂;3种脱硫剂的表面反应活化能相近,分别是22.1,20.1,25.7kJ/mol;而扩散活化能差别较大,分别是49.6,26.0,19.4kJ/mol.可见织构对氧化铁脱硫剂性能的影响是通过扩散引起的.

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

It is of great significance to study the effect of texture on the performance of the sorbent 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 sorbents 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.