Study On Low NO_x Combustion Transformation On A 300MW Sub-Critical Unit Boiler

With the development of China's economy and the rapid growth of GDP,the problem of environmental pollution is becoming more and more serious.As of the beginning of2015,nationwide smoke dust emissions by 70%,SO₂ emissions by 85%,NO_x emissions by67%come from coal based fossil fuel combustion.In China's coal consumption,coal accounts for about half of electricity generation.In the process of coal-fired power plant,the generated NOx is composed of NO,N2O3 and N2O.Among them,NO and NO2 are the main pollutants,which pose a serious threat to the ecological environment and human health.Therefore,it is very important to control the emission of NO_x in the process of coal combustion.It is of great social value to carry out the design and transformation of low NO_x burner.On the basis of summarizing and analyzing the low NO_x combustion technology at home and abroad,this paper work out the transformation scheme of the low NO_x burner on the basis of the 300MW subcritical boiler in Shanxi Weihe power plant.The composite air staging technology,low NO_x burner,high position separation overfire air,and other measures that ensure economic efficiency of the boiler are adopted.Realized the antielogging;anticorrosive,efficient stable-combustion while achieving the function of reducin NO_x.Before the transformation,when burning coal of high volatile,NO_x emission value is400⁷00mg/Nm³?dry state,O₂=6%?.when bituminous coal:lean coal=1:1,NO_x emission is 900mg/Nm³?dry state,O₂=6%?when burning lean coal,NO_x emissions ranged from1200 to 1500mg/Nm³?dry state.O₂=6%?;after the transformation,when burning the designed coal?bituminous coal::lean coal=1:1?,NO_x emission at furnace outlet is350mg/Nm³?dry state,O₂=6%?,the test results show that after the transformation,the problem of high NO_x emission is solved.When burning the coal that suitable for burning,the boiler efficiency achieves the target by more than 9 1.6%,and obtains a good environmental protection benefits and economic benefits.