水泥工业富氧燃烧条件下钙基捕集剂的碳酸化反应动力学

Kinetics of Carbonation Reaction of Calcium-based Sorbents under Oxygen-enriched Combustion in Cement Industry

以天然石灰石煅烧制备的钙基捕集剂循环煅烧/碳酸化协同捕集水泥富氧燃烧工业烟气中的CO2为研究背景,采用热重分析仪对钙基捕集剂的碳酸化反应动力学进行研究。采用改进的双外推法对反应动力学参数进行计算。结果表明:化学控制阶段的反应模型是随机成核和随后生长模型,得到了最概然机理函数,反应级数为1/2;扩散控制阶段的反应模型是相边界反应收缩球模型,得到了最概然机理函数,反应级数为1/3;当气氛中CO2浓度由50%增加至80%时,化学控制和扩散控制两阶段的活化能分别由147.58和215.03kJ/mol降低至130.06和170.10kJ/mol。

The kinetics of carbonation reaction of calcium-based sorbents prepared from calcined limestone in a cyclic process of calcination and carbonation under the condition of oxygen-enriched combustion to capture COz from cement industrial flue gases was investigated v/a thermogravimetric analysis. The kinetic parameters of reaction were calculated by an improved double ex- trapolation method. The results show that the reaction model is a ＂randomly nucleation＂ model and a ＂followed growth＂ model as well. The reaction order is 1/2 in chemical control phase in the most probable mechanism function. Moreover, in the diffu- sion controlled phase, the reaction model is a ＂spherical interface contraction reaction＂ model, and the reaction order is 1/3 in the most probable mechanism function. When CO2 concentration increases from 50% to 80% in the atmosphere, the required reaction activation energy E decreases from 147.58 kJ/mol to 130.06 kJ/mol in the chemical controlled phase, and 215.03 kJ/ tool to 170. 10 kJ/mol in the diffusion controlled phase, respectively.