Microstructure characteristics and desulphurization of nano-CaCO₃ during coal combustion

The desulphurization performance of nano-CaCO₃ 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-CaCO₃ 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-CaCO₃ can improve the desulphurization process due to its abundant pores. The desulphurization efficiency is increased by adding nano-Al₂O₃ and nano-ZnO. The nano-Al₂O₃ additive improves the desulphurization rate by 20% at 1150℃.