| The improvement of ultra-low emission of coal-fired boiler is the near future focus of energy saving and emission reduction work for coal-fired power plant.It is a common problem that current coal-fired boilers regularly run in deeply peak load lead to the low efficiency and pollutant discharge is difficult to control.It started from the ultra-low emission technologies and methods.Firstly,600 MW supercritical coal-fired unit of a domestic power plant was used as the research object.It investigates the coordinated control and interactive mechanism of desulfurization,denitrification and dedusting in different pollutant control technologies.Secondly,the relationship between NOx emission and related factors was studied in the study of 150 MW CFB boiler in Tangshan power plant.The results showed that operation optimization of coal-fired units low NOx combustion and SCR technology could ensure NOx concentration of flue gas in outlet is lower than 50 mg/m3,and integrated technology of desul-furization and dedusting that adding gas cooler and gas reheated before and after low temperature ESP could control flue gas temperature in a lower level,which make SO2 and dust emission concentration respectively lower than 35 mg/m3 and 5 mg/m3.It was helpful to control NOx emission with the increase of unit load,water coal ratio and ammonia nitrogen ratio.Flue gas oxygen content was controlled under 5%,and keeping the denitration process best SNCR reaction temperature range,which can effectively improve the denitration efficiency,but it can't separate change the ratio of secondary air furnace,which need to comprehensively consider other factors such as bed temperature,excess air coefficient.The operation optimization in coal-fired boiler makes the pollutant emission value reach the level of gas-fired power plant.The research could provide technical support of ultra-low emission project re-construction and operation optimization for a coal-fired unit. |
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