O2/CO2气氛下石灰石煅烧与硫化反应研究

富氧燃烧技术是一种能够综合控制燃煤污染物排放的新型洁净燃烧技术。本文对O2/CO2气氛下煤燃烧流化床条件下的石灰石煅烧分解特性进行了热力学分析，并与热重试验结果进行了对比，得出石灰石的起始分解温度随O2/CO2气氛中CO2分压比的增大而增加，但增幅减小。结合小型流化床试验装置上煅烧与硫化反应过程中的石灰石样品的孔结构特性和可视化SEM分析，得出空气气氛和O2/CO2＝20/80气氛在煅烧与硫化反应过程中的孔结构特性差异很大：反应温度为1 123 K时，空气气氛下石灰石迅速分解，比表面积、孔隙率增大，硫化反应发生后孔堵塞导致比表面积、孔隙率减小；1 123 K的煅烧温度还不足以使O2/CO2＝20/80气氛下的石灰石分解，硫化反应过程中还伴随着石灰石的煅烧分解。

CALCINATION AND DESULFURIZATION OF LIMESTONE UNDER O2/CO2 ATMOSPHERE

Oxygen-enriched combustion of coal is one of the new technologies that can control pollutants emission. Thermodynamic analysis for calcination of limestone under O2/CO2 atmosphere in fluidized bed condition was carried out, which is accorded with the TG (Thermal Gravity) results. The initial decomposition temperature of CaCO3 was increased with increasing CO2 partial pressure. Calcination and desulfurization of limestone under O2/CO2 atmosphere were performed in a fluidized bed test-facility. Calcined and desulfurized limestones were analyzed by PM (Press Mercury) and SEM (Scanning Electron Microscope). Pore structure characteristics were different between atmosphere of air and O2/CO2 ratio of 1∶4 during the process of calcination and desulfurization. Limestone sulfuration under O2/CO2 atmosphere was accompanied by calcination.