SCR烟气脱硝对PM<sub>2.5</sub>排放特性的影响机制研究

束航; 张玉华; 杨林军; 刘亚明; 李方勇; 徐齐胜; 盘思伟

SCR烟气脱硝对PM_2.5排放特性的影响机制研究

1.
东南大学能源热转换及其过程测控教育部重点实验室, 江苏南京 210096;
2.
广东电网有限责任公司电力科学研究院, 广东广州 510080

基金项目: 国家重点基础研究发展规划(973计划,2013CB228505)和广东电网有限责任公司科技项目(K-GD2013-055)资助项目

详细信息

通讯作者:
杨林军,E-mail:ylj@seu.edu.cn

中图分类号: X511
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- 文章访问数: 399
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- 被引次数: 0
出版历程
- 收稿日期: 2015-06-02
- 修回日期: 2015-08-27
- 刊出日期: 2015-12-30

Effects of SCR-DeNO_x system on emission characteristics of fine particles

1.
Southeast University, Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Nanjing 210096, China;;
2.
Electric Power Research Institute of Guangdong Power Grid Company, Guangzhou 510080, China

Funds: The project was supported by the Major State Basic Research Development Program of China (973 program, 2013CB228505) and the Science and Technology Project of Electric Power Research Institute of Guangdong Power Grid Company (K-GD2013-055).

摘要

摘要: 采用V₂O₅-WO₃/TiO₂催化剂,对选择性催化还原(SCR)烟气脱硝装置出口PM_2.5物性进行分析,考察SO₂氧化与PM_2.5形成的关系,并采用原位漫反射红外光谱(DRIFTS)对SCR脱硝过程中NH₄HSO₄的生成及SCR脱硝温度条件下的NH₄HSO₄热稳定性进行了分析研究。结果表明,经SCR脱硝后,亚微米级细颗粒数浓度明显升高,且形貌特征及元素组成发生变化,形成的细颗粒主要为NH₄HSO₄及少量(NH₄)₂SO₄;SCR烟气脱硝对PM_2.5排放特性的影响主要通过以下途径:一是SO₃与SCR烟气脱硝系统中的NH₃、H₂O反应形成;二是SO₃与逃逸的NH₃、H₂O在SCR脱硝装置后续系统发生反应形成硫酸氢铵与硫酸铵;此外还与SO₃和烟气中游离的CaO等碱土金属氧化物反应形成硫酸盐,随烟气携带出SCR脱硝装置有关。
- 细颗粒物 /
- SCR脱硝 /
- 排放特性 /
- 影响机制
Abstract: Based on V₂O₅-WO₃/TiO₂ catalyst, the size distribution, morphology, element compositions and chemical compositions of fine particles at the output of SCR-DeNO_x system were analyzed, and the formation mechanism of fine particles were discussed based on DRIFTS systematically. The results show that great quantities of particles can be formed during the process of SCR-DeNO_x. The main components of particles are ammonium bisulfate and a small amount of ammonium sulfate. The effects of SCR-DeNO_x system on emission characteristics of fine particles attribute to three aspects. Firstly, some SO₂ can be oxided to SO₃ during SCR process at the function of catalyst, and then SO₃ would react with NH₃ and H₂O to form ammonium sulfate and ammonium bisulfate particles, which is a reversible process simultaneous with the de NO_x reactions. Secondly, SO₃ can also react with the escaped NH₃ and H₂O to form ammonium sulfate and ammonium bisulfate particles after SCR system. Moreover, the free alkaline earth metal oxide in the flue gas(such as CaO) reacts with SO₃ and changes the physical properties of the fine particles.
- fine particle /
- SCR /
- emission characteristics /
- influencing mechanism

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