【摘 要】
：
The poisoning of alkali metal salts in fly ashes on MnOx-TiO2 catalysts is one of the most important problems in the selective catalytic reduction (SCR) of NOx by NH3.In this work, MnOx-TiO2 catalysts
【机 构】
：
College of Materials Science and Engineering, Beijing University of Technology, Beijing, P.R.China
【出 处】
：
The 14th International Congress on the Chemistry of Cement (
论文部分内容阅读
The poisoning of alkali metal salts in fly ashes on MnOx-TiO2 catalysts is one of the most important problems in the selective catalytic reduction (SCR) of NOx by NH3.In this work, MnOx-TiO2 catalysts were prepared by sol-gel method.KNO3, KC1 and K2SO4were doped respectively on MnOx/TiO2 catalysts then calcinated at temperature of 500℃ for 3 hours to simulate the poisoning of K2O(decomposed by KNO3), KCl and K2SO4.To investigate the micro structure and performance of catalyst before and after poisoning, BET, XRD,SEM, XPS, H2-TPR and NH3-TPD were employed.The effects of different sylvites on catalysts were studied on the SCR activity reactor in the temperature range 90℃-330℃.It was found that: All of the three kinds of sylvites caused varying degrees of deactivation on catalysts, among which the KNO3 exhibited greater poisoning effect than KC1 and K2SO4.The BET studies showed that KNO3, KC1 and K2SO4 caused the similar decrease of specific surface area and pore volume, but the NH3-TPD studies revealed that the quantity of acid sites for KNO3-MnOx/TiO2 reduced greatly while KC1-MnOx/TiO2 and K2SO4-MnOx/TiO2 both reduced slighter.The H2-TPR result showed that the reduction peaks shifted to apparently higher temperatures with the loading of KNO3 while this phenomenon was not observed on the KC1-MnOx/TiO2 and K2SO4-MnOx/TiO2 catalysts.The results above indicate that the deactivation of catalysts was mainly attributed to the decrease of surface area, Bronsted acid sites and the reducibility.
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