摘要
氮氧化物NOx(NO, NO_2和N_2O)是全球大气污染的主要污染物之一,引起光化学烟雾、酸雨、臭氧层破坏等环境问题,严重影响人们的生存环境和生活质量,引起了世界各国的广泛关注。针对固定源和移动源燃烧排放,各国制定了日益严格的排放标准。目前主要的脱硝技术分为选择性催化还原(SCR)、选择性非催化还原(SNCR)、氧化脱硝和活性炭吸附脱硝等。SNCR的应用有较高的条件,影响其成功运行的主要因素有温度、氨氮比、氨气在烟气中的分布和停留时间等,故SNCR的工业应用存在一定的局限性。SCR脱硝技术比其它脱硝技术应用更广泛,其中脱硝多安排于除尘脱硫后,此时温度多处于100～250℃之间。为提高SCR脱硝性能,低温SCR脱除NOx是目前研究最热门的烟气脱硝技术。本工作综述了近年来低温SCR脱硝催化剂的研究进展,介绍了锰基催化剂、钒基催化剂及碳基催化剂的发展现状,对单组分Mn基催化剂、负载型Mn基催化剂和复合型Mn基催化剂进行了综述,从V基催化剂的制备对脱销的影响和脱硝机理进行了表述,综述了过渡金属掺杂对C基催化剂的影响,阐述了烟气中H2O和SO2对催化反应的影响及低温SCR反应的脱硝机理,对低温SCR催化剂进行了总结并对其未来发展进行了展望。
Nitrogen oxide NOx(NO,NO2,and N2O)is one of the major pollutants in the air pollution,it can cause environmental problems such as photochemical smog,acid rain,and ozone layer destruction,which has posed threat to people’s living environment and quality of life,and attracted great attention from the world.Countries made stricter emission standards for burning emissions from both fixed and mobile sources.The major denitrification technologies include selective catalytic reduction(SCR),selective non-catalytic reduction(SNCR),oxidative denitrification,and activated carbon adsorption and denitrification at present.The SNCR has higher conditions in industrial applications,the main factors affecting successful operation are temperature,ammonia-nitrogen ratio,distribution of ammonia gas in the flue gas and residence time,so there were certain limitations in industrial application of SNCR.Compared with other denitrification technologies,SCR denitration technology is more widely used in industrial application,in which denitration is mostly arranged after dust removal and desulfurization,at this time,the temperature is mostly between 100250℃.The performance of SCR denitrification in low-temperature must be improved,which is one of the most promising flue gas DeNOx technology.In this paper,the recent works on low-temperature SCR catalysts were reviewed on manganese-based catalysts,vanadium-based catalysts and carbon-based catalysts.Single-component Mn-based catalysts,supported Mn-based catalysts and composite Mn-based catalysts were reviewed,the effects of preparation of V-based catalysts on the de-dumping and denitrification mechanisms were described.The effect of transition metal doping on C-based catalysts was reviewed.The influence of H2O and SO2 resistance on low-temperature NH3-SCR catalytic activity and reaction mechanism were also discussed.Finally,the virtues advantages and defects of low temperature SCR catalysts were summarized,and the future development direction was also given out.
作者
宁汝亮
刘霄龙
朱廷钰
Ruliang NING;Xiaolong LIU;Tingyu ZHU(School of Chemistry and Chemical Engineering,Guizhou University,Guiyang,Guizhou 550025,China;National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China;Center for Excellence in Regional Atmospheric Environment,Institute of Urban Environment,Chinese Academy of Sciences,Xiamen,Fujian 361021,China)
出处
《过程工程学报》
CAS
CSCD
北大核心
2019年第2期223-234,共12页
The Chinese Journal of Process Engineering
基金
Supported by National Key Research and Development Program(No.2017YFC0210500)
关键词
低温
选择性催化还原
脱硝
催化剂
机理
low-temperature
selective catalytic reduction
denitrification
catalyst
mechanism
