摘要
选择性催化还原(SCR)具有效率高、技术成熟的优势,但处理球团烟气需要加热才能达到SCR脱硝的反应温度,导致能耗和运行成本高。氧化球团预热Ⅱ段(PH段)烟气温度在300℃以上,满足SCR反应所需温度,但是烟气中含有的SO_(2)和H_(2)O(g),会对催化剂的脱硝性能产生影响。研究了PH段烟气中SO_(2)和H_(2)O(g)对V/Ti催化剂脱硝性能的影响规律及机制,结果表明:SO_(2)和H_(2)O(g)均会一定程度降低催化剂的脱硝性能,H_(2)O(g)对脱硝的影响要比SO_(2)的影响小并且可逆。SO_(2)和H_(2)O(g)同时存在时对催化剂的脱硝性能影响最大且不可恢复,在10%H_(2)O(g)+1100 mg/m^(3)SO_(2)浓度下反应5 h后催化剂的脱硝率从96.1%降低至77.2%。烟气中的SO_(2)和H_(2)O(g)与NH_(2)反应生成的硫酸铵盐在催化剂表面沉积吸附,使反应后的催化剂比表面积降低且分散度降低,不利于NO和NH_(2)的吸附从而降低催化剂的脱硝性能。因此,烟气中SO_(2)和H_(2)O(g)含量的控制,以及脱硝条件的优化对PH段SCR脱硝至关重要。
Selective catalytic reduction(SCR)has the advantages of high efficiency and mature technology,but the flue gas of the pellets needs to be heated to reach the reaction temperature of SCR denitrification,resulting in high energy consumption and operating costs.The flue gas temperature of oxidized pellet preheating section II(PH section)is above 300℃,which meets the temperature required for the SCR reaction,but the SO_(2)and H_(2)O(g)contained in the flue gas will affect the denitrification performance of the catalyst.The effect of SO_(2)and H_(2)O(g)in the flue gas in the PH section on the denitrification performance of the V/Ti catalyst and its mechanism were studied.The results show that both SO_(2)and H_(2)O(g)will reduce the denitrification performance of the catalyst to a certain extent.The effect of denitrification is smaller and reversible than that of SO_(2).The presence of SO_(2)and H_(2)O(g)has the worst impact on the denitrification performance of the catalyst and is irreversible.The denitrification rate of the catalyst decreases from 96.1%to 77.2%after reacting for 5 hours at a concentration of 10%H_(2)O(g)+1100 mg/m^(3)SO_(2).The ammonium sulfate formed by the reaction of SO_(2)and H_(2)O(g)in the flue gas with NH_(2)is deposited and adsorbed on the surface of the catalyst,which reduces the specific surface area and dispersion of the reacted catalyst,which is not conducive to the adsorption of NO and NH_(2),thereby reducing the denitrification performance of the catalyst.Therefore,the control of the content of SO_(2)and H_(2)O(g)in the flue gas and the optimization of the denitrification conditions are very important for the SCR denitrification in the PH section.
作者
范晓慧
朱渊
甘敏
季志云
孙增青
武钰丰
FAN Xiaohui;ZHU Yuan;GAN Min;JI Zhiyun;SUN Zengqing;WU Yufeng(School of Resource Processing and Biological Engineering,Central South University,Changsha 410083,Hunan,China)
出处
《钢铁研究学报》
CAS
CSCD
北大核心
2022年第5期429-437,共9页
Journal of Iron and Steel Research
基金
国家自然科学基金资助项目(51974371)。
