摘要
论述了Pr对TiO_(2)的改性及后续在燃烧中脱硝的应用。采用微波辅助溶胶凝胶法制备了不同掺杂比例的Pr-TiO_(2)。与TiO_(2)相比,Pr-TiO_(2)的粒径减小,比表面积增大,锐钛矿型含量增加,催化活性增强。研究了Pr-TiO_(2)对煤与生物质掺烧时脱硝的影响,燃烧实验优化了最佳实验条件为水稻秸秆+乙酸钙(Ca/S=2.3)+Pr-TiO_(2)(2%)。实验结果表明,添加剂对低挥发分、中高硫分的单煤和混煤适应性好,脱硝效率最高可达92.2%。同时,水稻秸秆和Pr-TiO_(2)能降低煤的着火点,促进燃烧,降低煤灰结渣程度。机制分析认为添加剂促进脱硝可分为两部分:一是均相反应,添加剂促进煤中N-5和N-6向N-Q的转化,促进了NH_(3)对NO的还原;混合物热解产生CnHm等还原性气体,与NO_(x)中间产物HCN竞争O_(2),减少NO_(x)生成,同时将NO还原为N_(2);二是异相反应,添加剂的加入,增强了煤焦活性位点,促进煤焦异相还原NO;使煤焦碳结构中无定序和缺陷结构增加,吸附活性增强,NO_(x)脱除率得以提高。
This paper states the modification of TiO_(2) by Pr and the subsequent application in denitrification in combustion.Pr-TiO_(2) with different doping ratios was prepared by microwave-assisted sol-gel method.Compared with TiO_(2),the particle size of Pr-TiO_(2) decreases,the specific surface area increases,the anatase type content increases,and the catalytic activity is enhanced.Later,the effect of Pr-TiO_(2) on denitrification when coal is blended with biomass was investigated,and the combustion experiment optimized the optimal experimental conditions as rice straw+calcium acetate(Ca/S=2.3)+Pr-TiO_(2)(2%).The experimental results show that the additives are well adapted to single and blended coals with low volatile matter and medium to high sulfur,and the denitrification efficiency is up to 92.2%.Meanwhile,rice straw and Pr-TiO_(2) can lower the ignition point of coal,promote combustion and reduce the degree of coal ash caking.The mechanism analysis suggests that the additives promote denitrification can be divided into two parts:the first is the homogeneous reaction,where the additives promote the conversion of N-5 and N-6 to N-Q in coal,which promotes the reduction of NH_(3) to NO;the mixture pyrolysis produces reducing gases such as Cn Hm,which competes with NO_(x) intermediate HCN for O_(2) and reduces NO_(x) generation while reducing NO to N_(2);the second is the heterogeneous reaction,where the addition of additives enhances the active site of coal coke and promotes the heterogeneous reduction of NO by coal coke;it increases the amorphous and defective structure of coal coke carbon structure and enhances the adsorption activity,and the NO_(x) removal rate can be improved.
作者
王淑勤
曹帅
刘丽凤
程伟良
Wang Shuqin;Cao Shuai;Liu Lifeng;Cheng Weiliang(Department of Environmental Science and Engineering,North China Electric Power University,Baoding 071003,China;Department of Energy,Power and Mechanical Engineering,North China Electric Power University,Beijing 100084,China)
出处
《中国稀土学报》
EI
CAS
CSCD
北大核心
2024年第5期935-946,I0004,共13页
Journal of the Chinese Society of Rare Earths
基金
国家重点研发计划项目(2018YFB060420103)资助。
