化工学报 ›› 2017, Vol. 68 ›› Issue (8): 3225-3231.DOI: 10.11949/j.issn.0438-1157.20170095

• 能源和环境工程 • 上一篇    下一篇

煤粉炉SNCR对SO3生成影响的数值模拟

沈文锋, 向柏祥, 张海, 张扬, 吕俊复   

  1. 清华大学热能工程系, 热科学与动力工程教育部重点实验室, 北京 100084
  • 收稿日期:2017-01-20 修回日期:2017-03-08 出版日期:2017-08-05 发布日期:2017-08-05
  • 通讯作者: 张海
  • 基金资助:

    国家自然科学基金项目(51476088)。

Numerical simulation on formation of SO3 during SNCR process in pulverized coal-fired boiler

SHEN Wenfeng, XIANG Baixiang, ZHANG Hai, ZHANG Yang, LÜ Junfu   

  1. Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084, China
  • Received:2017-01-20 Revised:2017-03-08 Online:2017-08-05 Published:2017-08-05
  • Supported by:

    supported by the National Natural Science Foundation of China(51476088).

摘要:

基于详细化学反应机理,利用CHEMKIN-PRO软件中的平推流反应器研究了选择性非催化还原(SNCR)脱硝过程对SO3生成作用,以及烟气中SO2、NO、O2和H2O的体积浓度对SO3生成量的影响。结果表明,氨的注入改变了SO3生成机理和主要路径,明显促进烟气中SO2向SO3氧化。在NH3的体积浓度为300 μl·L-1、SO2的体积浓度为2000 μl·L-1、停留时间1.9 s内温度从1373 K降低至573 K时,生成的SO3体积浓度大于10 μl·L-1。随着SO2体积分数的降低,生成的SO3体积浓度减小,但转化率有所增加;此外生成的SO3体积浓度随O2体积浓度、NO体积浓度和停留时间的增加而增加,随着H2O体积浓度的增加而减小。燃用高硫煤时,SNCR对SO3的生成作用必须给予重视。

关键词: 选择性非催化还原, 氨, 二氧化硫, 三氧化硫, 平推流反应器

Abstract:

A numerical investigation on the formation of SO3 during selective non-catalytic reduction (SNCR) process and the influences of the concentrations of SO2, NO, O2, and H2O were performed using the plug flow reactor of the CHEMKIN-PRO software with a detailed chemical kinetic mechanism. The simulation results showed that the presence of NH3 changed the formation mechanism and reaction pathway of SO3 and noticeably enhanced the formation of SO3. When the reaction temperature decreased from 1373 K to 573 K within 1.9 s residence time with inlet NH3 concentration being 300 μl·L-1 and inlet SO2 concentration being 2000 μl·L-1, the formation concentration of SO3 was above 10 μl·L-1. The SO3 concentration decreased while SO3/SO2 conversion ratio slightly increased with increasing inlet concentration of SO2. Meanwhile, SO3 concentration increased with increasing inlet concentrations of O2 and NO, and decreased with increasing H2O inlet concentration in the flue gas. Based on the study, the formation of SO3 during SNCR process should be paid attention when high sulfur coal was burned.

Key words: selective non-catalytic reduction, ammonia, sulfur dioxide, sulfur trioxide, plug flow reactor

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