Pr-TiO2对煤与生物质掺烧NOx排放的影响
Effect of Pr-TiO2 on NOx Emissions during Coal Combustion
王淑勤 1曹帅 1刘丽凤 1程伟良2
作者信息
- 1. 华北电力大学环境科学与工程系,河北保定 071003
- 2. 华北电力大学能源动力与机械工程学院,北京 100084
- 折叠
摘要
论述了 Pr对TiO2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-TiO2.与TiO2相比,Pr-TiO2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-TiO2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-TiO2(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-TiO2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 NH3对NO的还原;混合物热解产生CnHm等还原性气体,与NOx中间产物HCN竞争O2,减少NOx生成,同时将NO还原为N2;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,NOx脱除率得以提高.
Abstract
This paper states the modification of TiO2 by Pr and the subsequent application in denitrification in combustion.Pr-TiO2 with different doping ratios was prepared by microwave-assisted sol-gel method.Compared with TiO2,the particle size of Pr-TiO2 decreases,the specific surface area increases,the anatase type content increases,and the catalytic activity is enhanced.Later,the effect of Pr-TiO2 on denitrifiication when coal is blended with biomass was investigated,and the combustion experiment optimized the optimal experimental con-ditions as rice straw+calcium acetate(Ca/S=2.3)+Pr-TiO2(2％).The experimental results show that the addi-tives 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-TiO2 can lower the ignition point of coal,promote combustion and reduce the degree of coal ash caking.The mechanism analysis suggests that the addi-tives promote denitrification can be divided into two parts:the first is the homogeneous reaction,where the addi-tives promote the conversion of N-5 and N-6 to N-Q in coal,which promotes the reduction of NH3 to NO;the mixture pyrolysis produces reducing gases such as CnHm,which competes with NOx intermediate HCN for O2 and reduces NOx generation while reducing NO to N2;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 ac-tivity,and the NOx removal rate can be improved.
关键词
Pr改性TiO2/生物质/乙酸钙/掺烧/NOx减排机制Key words
Pr-modified TiO2/biomass/calcium acetate/co-firing/NOx emission reduction mechanism引用本文复制引用
基金项目
国家重点研发计划项目(2018YFB060420103)
出版年
2024
NETL
NSTL
万方数据