煤燃烧过程中钙基材料除砷脱硫的试验研究

文章以贵州高砷煤为研究对象,运用固定床管式炉对钙基材料在煤燃烧过程中的除砷脱硫性能及影响因素进行了系统研究,并对燃煤灰渣进行了X-射线衍射分析和扫描电镜观察,简单地探讨了钙基材料的除砷脱硫机理。实验结果表明:在燃烧温度为1 050℃,钙基材料用量n(Ca)/n(S)=2.0时,粒径越小的钙基材料除砷脱硫效果越好,钙基材料在一定的条件下具有良好的同时除砷脱硫的性能;其除砷脱硫的机理是钙基材料的加入促进了As2O3和SO2的扩散,并且与As2O3和SO2生成了Ca3(AsO4)2和CaSO4以固相停留在燃煤灰渣中,从而降低了砷和硫挥发进入大气的程度。

Study of simultaneous dearsenic and desulfurization by calcium-based materials during coal combustion

Taking high arsenic coal in Guizhou as object of study,the characteristics of calcium-based materials for dearsenic and desulfurization and the influence of different factors on the dearsenic and desulfurization rate during coal combustion were investigated by using a fixed-bed tube-type furnace.The ashes from burning different coal samples were tested and observed respectively with X-ray diffraction and scanning electron microscopy.The mechanism of calcium-based materials for dearsenic and desulfurization was also discussed.The results show that the smaller are the particle size of calcium-based materials,the better is dearsenic and desulfurization rate when combustion temperature is 1 050 ℃ and n(Ca)/n(S) is 2.0.The calcium-based materials can be applied to the coal combustion for simultaneous dearsenic and desulfurization under certain condition.The mechanism of calcium-based materials for dearsenic and desulfurization is considered that it not only contributes to the spread of As2O3 and SO2 but also responses to As2O3 and SO2 to generate Ca3(AsO4)2 and CaSO4 which stay in the ashes by the solid phase,thus lowers the degree that arsenic and sulfur volatilization enter atmosphere.