现役燃煤机组SCR烟气脱硝装置运行现状分析

Analysis on Operating Status of SCR Facilities in Active Coal-Fired Units

为了给燃煤电厂超低排放改造提供借鉴,对国内26个电厂61台采用选择性催化还原(SCR)工艺燃煤机组的脱硝装置运行现状进行了分析,得到脱硝效率、进出口NO_x浓度、氨氮摩尔比、SO_2/SO_3转化率、逃逸氨、运行烟温、系统阻力、温降等脱硝装置各方面实际运行参数,掌握了燃煤机组脱硝装置主要性能。研究结果表明,大部分脱硝装置整体性能较为良好;所存在的问题主要包括:机组炉型、煤质、燃烧工况以及设计裕量等因素导致部分机组脱硝系统入口NO_x浓度偏离原设计值较多,喷氨不合理导致大部分机组氨氮摩尔比偏大并造成逃逸氨浓度超标,部分机组低负荷时脱硝系统入口烟温偏低,部分机组脱硝系统温降较大。对此提出了相应建议及意见。

In order to provide helpful reference for flue gas ultra-low emission retrofits, current operating status of the SCR flue gas denitration system are analyzed which have been installed on 61 generation units in 26 power plants. A variety of practical data are obtained including the denitration efficiency, inlet and outlet NOx concentrations, ammonia molar ratio, SO2/SO3 conversion rate, ammonia escape rate, running flue gas temperature, system resistance, temperature drop, etc. Also the major functionalities of the SCR denitration system are acknowledged. From the study results the overall performance is satisfactory for most of the denitration systems. However there still exist some problems as follows. The SCR system inlet NOx concentration deviates significantly from the original designed value due to the factors such as the furnace type, coal quality, combustion condition and design margin. The improper ammonia injection causes higher-than-normal ammonia molar ratio and consequentially the ammonia escape concentration exceeding the related standard. Low SCR system inlet flue gas temperature at low loadings and large system temperature drops are also noticed in some units. Therefore, suggestions and advice are put forward accordingly. This work is supported by China Huadian Corporation Science Program （No. CHDKJ-2015-G04）.