煤燃烧复杂体系中痕量元素迁移转化的热力学

Thermodynamic of Trace Element Mobilisation During Coal Combustion

用热力学平衡模拟方法研究了贵州六盘水烟煤燃烧过程中痕量元素Ni、Cr、Hg、As、Se和Sb在凝聚相和气相中的迁移转化.研究的体系为气相和包含氧化物和硫化物熔融体、熔融盐及固溶体凝聚相的复杂体系.分别研究了燃烧过程的3个阶段:燃烧初期的还原性气氛、燃烧完全的氧化性气氛以及燃后冷凝气氛中痕量元素迁移转化规律.用1 0K小步长法计算了在1 30 0K以下痕量元素从气相迁移至凝聚相的形态及其凝聚顺序.比较计算结果与文献报道的实验数据,结果吻合.在研究煤燃烧过程中痕量元素的迁移转化时,在凝聚相加入氧化物和硫化物熔融体、固溶体及熔融盐模型大大提高了热力学平衡模拟方法的准确度和真实性.

The thermodynamic equilibrium distributions of the trace elements nickel, chromium, mercury, arsenic, selenium and antimony between the condensed and gaseous phases were examined. Predictions were made using a comprehensive model of the various oxide and sulphide melt models, matte, salt and solid solution models. Three regimes for coal combustion were defined. The condensation sequence from the equilibrium gas phase at 1 300K was predicted on cooling by 10K steps. The calculated results agree with published experimental results. The comprehensive model enhances the value of the predictions.