纳米TiO_2对两种煤燃烧脱硫的对比分析

Comparable analysis of Nano-TiO_2 on combustion anddesulfurization for two kinds of coal

对纳米TiO2催化CaO燃烧脱硫进行了实验研究。探讨了纳米TiO2添加量、Ca/S摩尔比及燃烧温度对CaO脱硫的影响,还比较了纳米TiO2对不同煤种的脱硫效果。并对反应产物进行了X射线衍射、红外光谱和扫描电镜分析,讨论了纳米TiO2催化脱硫和催化燃烧机理。结果表明,纳米TiO2最佳的添加量为8%;在Ca/S摩尔比为2、燃烧温度为850℃时脱硫效率达87.8%,褐煤、烟煤比不添加纳米TiO2时脱硫效率分别增加13.4%和16.8%。纳米TiO2对不同煤种的催化作用表现为:改变CaO的晶格结构,增加比表面积,增加煤灰的孔尺寸,促进二氧化硫的扩散,同时使褐煤着火提前,烟煤易于燃烬,不仅提高CaO的脱硫效果还有利于强化燃烧。为纳米TiO2助燃脱硫的进一步应用奠定了基础。

The catalytic effects of nano-TiO2 to CaO desulfurization and coal combustion were studied. The effects of CaO desulfurization by nano-TiO2 addition, Ca/S molar ratio and combustion temperature were discussed. Desulfurization effects were compared with different coals by nano-TiOz addition. The reaction products were analyzed by X-ray diffraction analysis （XRD）, Infrared spectrographic analysis （IR） and Scanning electron microscopy （SEM） analysis. The combustion and desulfurization mechanisms of CaO by nano-TiO2 addition were discussed. When nano-TiO2 was added together with CaO, the optimal addition dosage of nano-TiO2 is 8%, Ca/S molar ratio is 2 and the combustion temperature is 850℃. The desulfurization efficiency of CaO catalyzed by nano-TiO2 can achieve to 87. 8%, the lignite and bituminous coals increased 13. 4% and 16. 8% respectively than that without nano-TiO2. The pore diameter and surface area of different coal ashes and CaO with nano-TiO2 addition increase because of the active centers of nano-TiO2 surface which are helpful to the diffusion of SO2 and the lignite ignition and the bituminous coal burnout. Therefore nano-TiO2 not only increases the desulfurization efficiency but also enhances the coal combustion efficiency simultaneously. The research will provide theoretic base for nano-TiO2 utilization as combustion desulfurization additive.