纳米碳酸钙微观特征及其促进燃煤脱硫特性研究

为了研究纳米碳酸钙和纳米添加剂在促进燃煤脱硫中的特性,在ZCS-1智能测硫仪中进行纳米碳酸钙脱硫实验研究。结果表明,在炉温900℃、钙硫比为2的条件下,脱硫效率高达90%;1 150℃时达到50%以上。三种纳米碳酸钙的脱硫效果明显好于普通碳酸钙。研究还表明,粒径越小,脱硫效果越好;不同煤种对脱硫效率有较大影响,主要和煤中硫分的含量和硫的分布形态有关;温度是决定脱硫效果的主要因素,900℃下效果最好,超过1 100℃后效果明显下降。SEM和BET分析结果表明,纳米碳酸钙促进脱硫主要是由于其较为丰富的孔隙结构。添加纳米Al2O3和纳米ZnO都能在一定程度上促进纳米碳酸钙脱硫。其中,纳米Al2O3的效果较好,1 150℃能使脱硫效率提高20%左右,达到62%以上。

Microstructure characteristics and desulphurization of nano-CaCO_3 during coal combustion

The desulphurization performance of nano-CaCO_3 during coal combustion was studied by using ZCS-1 intellective sulf-meter, and the effect of additives was also examined. The results show that the desulphurization efficiency is 90% when the temperatures is 900℃ and Ca/S ratio is 2, and more than 50% at 1150℃. Nano-CaCO_3 has a higher desulphurization efficiency than the ordinary calcium carbonate. It is indicated that the desulphurization efficiency decreases with the increasing of particle size. The coal type has a great influence on desulphurization due to its different contents and chemical state of sulfur. The temperature is the major factor for the desulphurization. The desulphurization efficiency reaches the highest value at 900℃, but obviously decreases when the temperature is over 1100℃. The SEM and BET results show that nano-CaCO_3 can improve the desulphurization process due to its abundant pores. The desulphurization efficiency is increased by adding nano-Al_2O_3 and nano-ZnO. The nano-Al_2O_3 additive improves the desulphurization rate by 20% at 1150℃.