二氧化碳浓度对石灰石分解反应动力学的影响

Effect on kinetics of limestone decomposition under different CO2 atmospheres

基于石灰石热重-差示扫描量热(TG-DSC)分析结果,分别在不同浓度的二氧化碳(二氧化碳与空气的混合气)气氛下对石灰石进行热分解特性研究。TG和DSC分析结果表明,碳酸钙分解是吸热反应,反应温度范围为750~950℃;提高升温速率,反应进程加快,TG曲线向高温区移动,DSC曲线吸热峰和吸热面积明显增大;反应气氛中二氧化碳浓度提高,TG曲线稍微向高温区移动,反应起始温度相同,反应终止温度相差约20℃。在高浓度二氧化碳气氛下,石灰石分解遵循随机成核和随后生长模型。此研究结果可为进一步优化石灰石煅烧工艺以及煅烧炉的设计提供理论支持。

Thermal decomposition characteristics of limestone were studied by thermal gravimetric differential scanning calorimetry(TG-DSC)under different concentrations of CO2(mixture of CO2 and air).The TG and DSC curves obtained from the experimental results showed that the decomposition of calcium carbonate was an endothermic reaction,and the reaction range was mainly in the range of 750~950℃;with the increasing of heating rate,the reaction speed was increased,and the TG curve was moved to the high temperature region.The DSC curve showed obvious increasing on endothermic peak and endothermic area;with the increasing of concentration of CO2 in the reaction atmosphere,the TG curve moved slightly to the high temperature region,the reaction initiation temperatures were always same,and the terminal reaction temperature differd by about 20℃.In a high concentration CO2 atmosphere,limestone decomposition followed a random nucleation and subsequent growth model.It provided theoretical support for further optimization of the limestone calcination process and the design of the calciner.