化工学报 ›› 2018, Vol. 69 ›› Issue (8): 3643-3650.doi: 10.11949/j.issn.0438-1157.20180051

• 能源和环境工程 • 上一篇    下一篇

燃煤锅炉烟气中Na2SO4生成的化学动力学研究

张志潮, 刘晶, 杨应举, 张振   

  1. 华中科技大学煤燃烧国家重点实验室, 湖北 武汉 430074
  • 收稿日期:2018-01-15 修回日期:2018-02-10 出版日期:2018-08-05 发布日期:2018-03-07
  • 通讯作者: 刘晶 E-mail:liujing27@mail.hust.edu.cn
  • 基金资助:

    国家重点研发计划项目(2016YFB0600604)。

Study on chemical kinetics of Na2SO4 formation in coal fired flue gas

ZHANG Zhichao, LIU Jing, YANG Yingju, ZHANG Zhen   

  1. State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China
  • Received:2018-01-15 Revised:2018-02-10 Online:2018-08-05 Published:2018-03-07
  • Supported by:

    supported by the National Key R&D Program of China (2016YFB0600604).

摘要:

准东煤燃烧过程中Na2SO4的形成会造成锅炉受热面沾污、尾部SCR催化剂失活等问题。烟气中Na2SO4形成及转化规律的研究对于预测和控制燃煤烟气中Na2SO4的形成有重要意义。发展了烟气中Na/Cl/S/O/H化学动力学模型,研究了烟气中Na2SO4的生成过程及转化机理,考察了含氧量、温度、SO2浓度、H2O浓度等因素对Na2SO4生成的影响。动力学计算结果表明,模型预测结果与实验数据吻合较好,验证了模型的准确性。烟气中的高氧气含量有利于Na2SO4的生成。高温加快化学反应的同时,抑制了Na2SO4的生成。SO2和H2O的影响效果受温度影响较大。反应路径分析表明,Na2SO4的生成路径有两个:一是依赖于SO2直接氧化(NaCl→NaSO3Cl→NaHSO4→Na2SO4),二是依赖于SO2间接氧化(NaCl→NaO2→NaSO4→NaHSO4→Na2SO4)。敏感性分析结果表明,Na2SO4的生成主要对系统中生成或消耗自由基的反应更为敏感。

关键词: 准东煤, 碱金属, Na2SO4生成, 化学动力学, 反应路径

Abstract:

The formation of gaseous sodium sulphate during Zhundong coal combustion leads to a series of problems such as the deposition and corrosion of heat exchange surface and the deactivation of tail SCR catalyst. Therefore, the kinetic study on the transformation of Na2SO4 is important for predicting and controlling the Na2SO4 formation in coal-fired flue gas. In this study, a more complicated chemical kinetic model of Na/Cl/S/O/H in flue gas was established and the formation mechanism of Na2SO4 was studied. The influence of oxygen content, temperature, SO2and H2O concentrations on Na2SO4 formation was also investigated. The model predictions were in good agreement with the experimental results. Oxygen promoted the formation of Na2SO4. Even though the chemical reactions were accelerated at high temperature, the Na2SO4 formation was inhibited. The effects of SO2 and H2O on Na2SO4 formation depended on reaction temperature. The path analysis indicated that there were two important paths to form Na2SO4:(1) the direct oxidation of SO2 (NaCl→NaSO3Cl→NaHSO4→Na2SO4), and (2) the indirect oxidation of SO2(NaCl→NaO2→NaSO4→NaHSO4→Na2SO4). The result of sensitivity analysis showed that the Na2SO4 formation was sensitive to the reactions that generated or consumed radicals in the system.

Key words: Zhundong coal, alkali metal, Na2SO4 formation, chemical kinetics, reaction path

中图分类号: 

  • TK16

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