摘要
准东煤燃烧过程中Na_2SO_4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Na_2SO_4形成及转化规律的研究对于预测和控制燃煤烟气中Na_2SO_4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Na_2SO_4的生成过程及转化机理,考察了含氧量、温度、SO_2浓度、H_2O浓度等因素对Na_2SO_4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Na_2SO_4的生成。高温加快化学反应的同时,抑制了Na_2SO_4的生成。SO_2和H_2O的影响效果受温度影响较大。反应路径分析表明,Na_2SO_4的生成路径有两个:一是依赖于SO_2直接氧化(Na Cl→Na SO3Cl→Na HSO4→Na_2SO_4),二是依赖于SO_2间接氧化(Na Cl→Na O_2→Na SO4→Na HSO4→Na_2SO_4)。敏感性分析结果表明,Na_2SO_4的生成主要对系统中生成或消耗自由基的反应更为敏感。
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,SO2 and 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.
作者
张志潮
刘晶
杨应举
张振
ZHANG Zhichao;LIU Jing;YANG Yingju;ZHANG Zhen(State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology,Wuhan 430074,Hubei,China)
出处
《化工学报》
EI
CAS
CSCD
北大核心
2018年第8期3643-3650,共8页
CIESC Journal
基金
国家重点研发计划项目(2016YFB0600604)~~
作者简介
张志潮(1992—),男,硕士研究生。;联系人:刘晶。
