快速加热条件下煤和碳酸钙的混合反应动力学研究

Reaction kinetics of mixed coal and calcium carbonate under rapid heating rates

建立了能够实时监测样品质量的高温垂直管式炉试验系统。试验过程中,煤粉的燃烧反应和CaCO 3的分解反应可以同时进行,其混合反应特性可以反映分解炉的真实情况。在900~1000℃工作温度区间内,温度变化对煤粉的燃烧反应影响很小,但温度是较低温度下CaCO 3分解的重要影响因素。随着混合物中CaCO 3质量的增加,反应速率对温度更敏感。当煤与CaCO 3质量比约为1∶9时,分解产物的BET(Brunauer,Emmett和Teller)比表面积最大。试验数据的动力学分析表明,在不同质量比下混合物的反应动力学模型不同,活化能随着煤与CaCO 3质量比的增加而降低。为了保证水泥分解炉中CaCO 3的分解率和煤的燃烧效率均较高,有必要将煤与CaCO 3质量比控制在1∶9以上。获得的活化能数据可以为预分解炉的后续模拟计算提供支持。

A high-temperature vertical tube furnace experimental system,capable of real-time monitoring the sample quality,was built in this study.The combustion reactions of pulverized coal and the decomposition reactions of calcium carbonate(CaCO 3)can be performed simultaneously,and the mixed reaction characteristics can reflect the real situation in the precalciner.During the operating temperature range of 900-1000℃,the variations in temperature had little effect on the combustion reactions of pulverized coal,but the temperature became an important factor affecting the CaCO 3 decomposition at lower temperature.With the mass ratio of CaCO 3 in the mixture increasing,the reaction rate was more sensitive to temperature.The BET(Brunauer,Emmett and Teller)specific surface area of decomposition product was largest when the mass ratio of coal to CaCO 3 was approximately 1∶9.The kinetic analysis of the experimental data shows that the reaction kinetics model of the mixture was different in different mass ratios.The activation energy value decreased with the increase in the mass ratio of coal to CaCO 3,and so did Arrhenius constant.To ensure the high decomposition ratio of CaCO 3 and the high combustion efficiency of coal in the cement precalciner,it is necessary to control the mass ratio of coal to CaCO 3 being higher than 1∶9.The activation energy data obtained from this study can provide support for the later simulation calculation of the precalciner.