化工进展 ›› 2023, Vol. 42 ›› Issue (7): 3770-3779.DOI: 10.16085/j.issn.1000-6613.2022-1614

• 资源与环境化工 • 上一篇    下一篇

硝酸生产尾气中NO x 和N2O联合脱除技术研究进展

李佳(), 樊星(), 陈莉, 李坚   

  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
  • 收稿日期:2022-09-01 修回日期:2023-03-03 出版日期:2023-07-15 发布日期:2023-08-14
  • 通讯作者: 樊星
  • 作者简介:李佳(1998—),女,硕士研究生,研究方向为大气污染控制。E-mail:591240968@qq.com
  • 基金资助:
    国家自然科学基金(21707004);北京市自然科学基金(8152011)

Research progress of simultaneous removal of NO x and N2O from the tail gas of nitric acid production

LI Jia(), FAN Xing(), CHEN Li, LI Jian   

  1. Key Laboratory of Beijing on Regional Air Pollution Control, Beijing University of Technology, Beijing 100124, China
  • Received:2022-09-01 Revised:2023-03-03 Online:2023-07-15 Published:2023-08-14
  • Contact: FAN Xing

摘要:

采用氨氧化法生产稀硝酸时会排放NO x (NO和NO2)和N2O等有害气体,可导致光化学烟雾(NO x )、臭氧层消耗(NO x 和N2O)、全球变暖(N2O)等环境问题,减少硝酸生产尾气中NO x 和N2O的排放势在必行。本文在分析硝酸生产过程中NO x 和N2O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N2O的主要技术路线,包括利用SCR催化剂同时催化NO x 和N2O还原和利用复合式催化剂同时催化NO x 还原和N2O分解等一段式工艺以及先催化N2O分解后催化NO x 还原、先催化NO x 还原后催化N2O还原和先催化NO x 还原后催化N2O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N2O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N2O分解的工艺在减少还原剂消耗量、促进N2O去除等方面具有优势,未来需围绕同步降低SCR脱硝和N2O分解所需温度、提高催化剂对共存气体(O2、H2O等)的耐受性等方面开展进一步研究。

关键词: 硝酸生产尾气, 氮氧化物, 温室气体, 选择性催化还原, N2O分解, 催化剂

Abstract:

Harmful gases such as NO x (NO and NO2) and N2O 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 N2O), and global warming (N2O). It is imperative to remove NO x and N2O from the tail gas of nitric acid production. After introducing the generation pathways and control measures of NO x and N2O during nitric acid production, we summarized the main technological routes for simultaneous removal of NO x and N2O from the tail gas according to the research, development and application situations, including one-stage processes such as simultaneous SCR of NO x and N2O, SCR of NO x and decomposition of N2O over a composite catalyst, and two-stage processes such as catalytic N2O decomposition followed by SCR of NO x, SCR of NO x followed by SCR of N2O, and SCR of NO x followed by catalytic N2O 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 N2O. The two-stage process of SCR of NO x followed by catalytic N2O decomposition, has advantages of low consumption of reducing agent and high purification efficiency of N2O. Further research should focus on lowering the temperatures of both SCR of NO x and catalytic N2O decomposition and improving the tolerance of catalysts to co-existing gases (O2, H2O, etc.).

Key words: tail gas of nitric acid production, nitrogen oxide, greenhouse gas, selective catalytic reduction (SCR), N2O decomposition, catalysts

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