氧化铁高温煤气脱硫剂再生动力学行为研究

摘要

在热天平装置上研究了SO2气氛下再生反应温度和反应气体中二氧化硫体积分数对氧化铁高温煤气脱硫剂再生行为的影响.实验结果表明,只有在温度高于600℃时氧化铁脱硫剂才可以进行再生,较高的反应温度和二氧化硫体积分数都有利于提高脱硫剂的再生反应速率.利用均匀反应模型确定了SO2气氛下脱硫剂的再生为一级反应,按照等效粒子模型对其动力学行为进行了分析.结果表明,二氧化硫气氛中氧化铁脱硫剂再生过程存在着由表面化学反应控制向内扩散控制的动力学控制步骤的转移过程.通过计算得出了再生反应表观动力学参数,化学反应速率常数的指前因子为8.79×1O7m/s,活化能为160.56kJ/mol;有效扩散系数的指前因子为6.4×10-3m2/s,扩散活化能45.40 kJ/mol.%The effects of regeneration temperature and SO2 concentration on the regeneration reactivity of iron oxide sorbent in SO2 atmosphere were investigated by using a thermogravimetric analyzer.The results show that iron oxide sorbent was regenerated only when the regeneration temperature was higher more than 600℃, and high regeneration temperature and SO2 concentration increased regeneration rate.The regeneration reaction order was confirmed to be the first order by using a homogeneous reaction model.Kinetic model tests show that the regenerationprocess was well fitted by the equivalent grain model.The kinetic controlling steps transformed from chemical reaction controlling at the early regenerating stage to inner diffusion controlling at the latter regenerating stage in the regeneration process in SO2 atmosphere.The apparent kinetic parameters of regeneration reaction of iron oxide sorbent were calculated according to the model.The apparent activation energy of the chemical reaction and corresponding frequency factor were 160.56 kJ/mol and 8.79×107 m/s, respectively,while the diffusion activation energy and corresponding frequency factor were 45.40 kJ/mol and 6.4× 10-3 m2/s, respectively.