硝酸生产尾气中NO_(x)和N_(2)O联合脱除技术研究进展  

Research progress of simultaneous removal of NO_(x) and N_(2)O from the tail gas of nitric acid production

作　　者：李佳[1] 樊星[1] 陈莉[1] 李坚[1] LI Jia;FAN Xing;CHEN Li;LI Jian(Key Laboratory of Beijing on Regional Air Pollution Control,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学区域大气复合污染防治北京市重点实验室,北京100124

出　　处：《化工进展》2023年第7期3770-3779,共10页Chemical Industry and Engineering Progress

基　　金：国家自然科学基金(21707004);北京市自然科学基金(8152011)。

摘　　要：采用氨氧化法生产稀硝酸时会排放NO_(x)(NO和NO_(2))和N_(2)O等有害气体,可导致光化学烟雾(NO_(x))、臭氧层消耗(NO_(x)和N_(2)O)、全球变暖(N_(2)O)等环境问题,减少硝酸生产尾气中NO_(x)和N_(2)O的排放势在必行。本文在分析硝酸生产过程中NO_(x)和N_(2)O产生途径及减排措施的基础上,根据国内外研发和应用情况总结了联合脱除硝酸生产尾气中NO_(x)和N_(2)O的主要技术路线,包括利用SCR催化剂同时催化NO_(x)和N_(2)O还原和利用复合式催化剂同时催化NO_(x)还原和N_(2)O分解等一段式工艺以及先催化N_(2)O分解后催化NO_(x)还原、先催化NO_(x)还原后催化N_(2)O还原和先催化NO_(x)还原后催化N_(2)O分解等两段式工艺,分析了不同技术路线的原理、特点及面临的挑战。文中指出了一段式工艺主要存在N_(2)O净化性能有待提升的问题,两段式工艺中先催化NO_(x)还原后催化N_(2)O分解的工艺在减少还原剂消耗量、促进N_(2)O去除等方面具有优势,未来需围绕同步降低SCR脱硝和N_(2)O分解所需温度、提高催化剂对共存气体(O_(2)、H_(2)O等)的耐受性等方面开展进一步研究。Harmful gases such as NO_(x)(NO and NO_(2))and N_(2)O are emitted during the production of dilute nitric acid by ammonia oxidation,which can lead to environmental problems such as photochemical smog(NO_(x)),ozone layer depletion(NO_(x) and N_(2)O),and global warming(N_(2)O).It is imperative to remove NO_(x) and N_(2)O from the tail gas of nitric acid production.After introducing the generation pathways and control measures of NO_(x) and N_(2)O during nitric acid production,we summarized the main technological routes for simultaneous removal of NO_(x) and N_(2)O from the tail gas according to the research,development and application situations,including one-stage processes such as simultaneous SCR of NO_(x) and N_(2)O,SCR of NO_(x) and decomposition of N_(2)O over a composite catalyst,and two-stage processes such as catalytic N_(2)O decomposition followed by SCR of NO_(x),SCR of NO_(x) followed by SCR of N_(2)O,and SCR of NO_(x) followed by catalytic N_(2)O decomposition.The principles and characteristics of different technological routes were analyzed.It was pointed out that the one-stage processes face challenges of improving the purification performance toward N_(2)O.The two-stage process of SCR of NO_(x) followed by catalytic N_(2)O decomposition,has advantages of low consumption of reducing agent and high purification efficiency of N_(2)O.Further research should focus on lowering the temperatures of both SCR of NO_(x) and catalytic N_(2)O decomposition and improving the tolerance of catalysts to co-existing gases(O_(2),H_(2)O,etc.).

关 键 词：硝酸生产尾气 氮氧化物 温室气体 选择性催化还原 N_(2)O分解 催化剂 

分 类 号：X51[环境科学与工程—环境工程]