石灰石煅烧与硫化条件下磨耗特性

Attrition of limestone during fluidized bed calcination and sulfation

石灰石磨耗特性对于循环流化床物料平衡和脱硫效率有重要影响。利用鼓泡床磨耗实验台,系统地研究了不同煅烧与硫化条件下,粒径、温度和SO2浓度对石灰石及其脱硫产物的磨耗速率的影响。实验结果表明,硫化反应会显著降低石灰石的磨耗速率,延迟到达稳定磨耗的时间;当硫化反应达到慢反应区时,脱硫产物磨耗速率趋于稳定。磨耗可以剥离颗粒表层CaSO4,从而提高脱硫剂转化率。相同反应条件下,脱硫产物钙转化率越高,石灰石磨耗速率越低。最后利用现有文献数据分析并验证了石灰石磨耗模型,能够较好地反映不同粒径石灰石的磨耗速率的差异。

Attrition characteristics of limestone has a significant effect on material balance and SO2 capture efficiency in circulating fluidized beds. A bubbling reactor system, equipped with a particle separation apparatus and mass spectrum analyzer, was used to investigate the mutual influence between the calcination and sulfation reactions and the limestone attrition under different conditions. The results showed that sulfation reaction would be significantly reduced the attrition rate, delaying the time for reaching to the stable attrition rate. As the sulfation reaction progressed, the outer surface layer of a CaO particle was gradually covered by CaSO4. After the initial fast reaction finished, the attrition rates of limestone tended to be stable. Attrition would remove the impervious sulfate layers and enhance the sulfation conversion. Besides, the attrition rate decreased with the increasing sulfation conversion at the same reaction condition. Finally, using the existing literature data to analyze and verify the limestone attrition model, it can better reflect the difference in attrition rate of limestone with different particle sizes.