Effect of Silica-Alumina Ratio of Catalysts on NO Decomposition Rate in Cement Kiln Exhaust

In order to deal with the pollution of NO in cement kiln exhaust, the study of NO catalytic decomposition catalyst obtained much more attention. The effect of silica-alumina ratio on NO decomposition rate in cement kiln without other reductant was studied. The NO decomposition rate of catalysts with different silica-alumina ratio was determined by infrared spectrometer. And pore structures and the microstructure of the catalyst were characterized separately by BET surface area, nitrogen adsorption-desorption and XRD. The results show that silica-alumina ratio of catalyst was preferred to be 50 with the best NO decomposition rate when the temperature was below 300 °C. The catalyst with silica-alumina ratio of 60 has the higher catalytic activity when the temperature was higher than 300 °C, and the decomposition rate achieved 70% at 600 °C. XRD results shows the crystallinity of catalysts increased as the silica-alumina ratio increased. BET surface area and the cumulative pore volume of catalysts gradually increased, and the average pore diameter gradually reduced with the increase of silica-alumina ratio.