NaClO_2湿法氧化脱硝污染物排放特征与监测方法研究  

Studies on Emission Characteristics and Monitoring Methods of Pollutants in Flue Gas by NaClO_2 Wet Oxidation and Denitrification

作　　者：胡月琪 郭建辉[1] 孔川[1] 张虎[1] 张超 侯帅[1] 李萌[1] HU Yueqi;GUO Jianhui;KONG Chuan;ZHANG Hu;ZHANG Chao;HOU Shuai;LI Meng(Beijing Key Laboratory of Airborne Particulate Matter Monitoring Technology/Beijing Municipal Environmental Protection Monitoring Center,Beijing 100048,China)

机构地区：[1]北京市环境保护监测中心/大气颗粒物监测技术北京市重点实验室,北京100048

出　　处：《生态环境学报》2018年第9期1706-1715,共10页Ecology and Environmental Sciences

基　　金：国家科技支撑计划项目(2013BAC17B01);环境保护公益性行业科研专项(20140914);北京市地方标准制修订项目(20171035)

摘　　要：针对应用NaClO_2作为氧化剂氧化吸收低温烟气中的NO_x,基于实际工业应用烟气排放的实测结果分析,探讨了脱硝烟气组分对NO_x和SO_2监测方法的影响,分析评估了烟气脱硝后NO_x的实际排放水平、净化效率及其影响因素,讨论了NaClO_2湿法氧化脱硝二次气态污染物的排放水平与特征,以期为制定科学合理的NO_x排放控制策略提供科学依据。研究选择北京市3家供热厂9台实际使用的NaClO_2湿法氧化脱硝燃煤供暖锅炉,根据相关文献烟气模拟试验的最佳试验条件,采用4种NO_x与SO_2监测方法,对其脱硝烟气中气态污染物的排放进行了实测。结果表明,锅炉烟气经MgO或NaOH湿法脱硫和NaClO_2湿法氧化脱硝后,SO_2基准氧含量排放浓度为2~7mg·m^(-3),低于北京市地方排放标准限值(10mg·m^(-3));而NO_x基准氧含量排放浓度为92~105mg·m^(-3),超过了现行北京市地方标准排放限值(80mg·m^(-3))。烟气净化装置SO_2净化效率高达99.1%~99.6%,NO_x净化效率为52.5%~74.3%,平均为65.1%。净化装置SO_2进口浓度与烟气氧含量不影响其净化效率,而NO_x的净化效率与净化装置NO_x进口浓度及烟气氧含量有一致的变化趋势。烟气氧含量可能对NaClO_2湿法氧化脱硝系统NO_x的净化效率有一定的制约作用,使净化后烟气中NO_x的基准氧含量排放浓度维持于某一特定排放水平。NaClO_2湿法氧化脱硝二次污染物Cl_2逸出严重,排放浓度为1.4~30mg·m^(-3),平均为12mg·m^(-3),超标率89.7%;而HCl排放浓度为0.22~11mg·m^(-3),平均为2.2mg·m^(-3),97.4%达标。NaClO_2湿法氧化脱硝后烟气组分复杂,应选择适宜的监测方法测定NaClO_2湿法氧化脱硝后烟气中NO_x和SO_2的排放。In view of the application of NaClO2 as oxidant and sorbent to remove NOx in low temperature flue gas and the analysis of the measured results,the influence of components of denitrification flue gas on monitoring methods of NOx and SO2 was discussed.The actual emission level,purification efficiency and influencing factors of NOx were analyzed and evaluated,respectively.And the emission level and characteristics of the secondary gaseous pollutants were discussed.It was hoped to provide a scientific basis for formulating a scientific and reasonable NOx emission control policy.In this study,nine coal-fired heating boilers with wet oxidation and denitrification using NaClO2 solution were selected from three heating plants in Beijing.According to the optimum operating conditions for flue gas simulation test in relevant literatures,using four monitoring methods of NOx and SO2,the emission of gaseous pollutants in denitrification flue gas were measured.The results showed that the SO2 emission concentration in the benchmark oxygen content was 2~7 mg·m-3 in flue gas by MgO or NaOH wet desulfurization and NaClO2 wet oxidation and denitrification,lower than 10 mg·m-3,the limits of local emission standard in Beijing.And the NOx emission concentration was 92~105 mg·m-3 in the benchmark oxygen content,exceeding 80 mg·m-3,the current limits of local emission standard in Beijing.The purification efficiency of SO2 was as high as 99.1%~99.6%,and the purification efficiency of NOx was 52.5%~74.3%,with an average of 65.1%.The SO2 inlet concentration of purification unit and the oxygen content in the flue gas didn’t affect its purification efficiency.But the purification efficiency of NOx had the same trend as the NOx inlet concentration and the oxygen content in the flue gas.However,the oxygen content of the flue gas might had a certain restrict the purification efficiency of NOx in NaClO2 wet oxidation and denitrification system,so that the NOx emission concentration of the purified flue gas in the benchmark oxygen content co

关 键 词：烟气脱硫 湿法氧化脱硝 亚氯酸钠 二次污染物 监测与评价 

分 类 号：X511[环境科学与工程—环境工程]