Study On Reconstruction Of Selective Catalytic Reduction Of Denitrification System In 300MW Power Plant

In recent years,air pollution is becoming increasingly serious,with the increasing concern about global environmental problems,Chinese environmental Indicators become more stringent,assessment standards of high energy-consuming enterprises are increasingly harsh.Fossil fuel combustion in coal-fired power plants is one of the main causes of large amounts of NOx emissio ns.At present,with the strict emission standard of pollutants concentration on countries in the planning of 13th Five-Year,domestic power plants have begun to launch desulfurization and gentrification projects to reduce emissions of sulfur oxides,nitrogen oxides.Based on the above research background,this paper briefly introduces the research and development of flue gas NOx removal technology in recent years,including low nitrogen combustion technology,selective non-catalytic reduction(SNCR)gentrification,selective catalytic reduction(SCR)gentrification,SNCR-SCR combined gentrification,focusing on the selective catalytic reduction(SCR)gentrification technology of a power plant.In the actual operation of the gentrification device,the gentrification device inlet smoke is too low lead to the device to exit the operation when the unit at low load.In view of this problem,this paper analyzes the advantages and disadvantages of various retrofitting methods,such as bypass flue reconstruction,water bypass transformation,economizer classification,elastic heat recovery technology and modified catalyst technology,and choose the level of low temperature super heater bypass flue technology combined with the actual power plant.The minimum load of gentrification,the size of the flue opening and the amount of flue gas are calculated,and the heat recovery of the boiler unit before and after the transformation is calculated.Finally,the expected effect and economy of the retrofit are evaluated.After the transformation,the NOx emission concentration of the unit is 82.5 mg/m~3,reached the existing"thermal power plant air pollutant discharge standards"(GB13223-2011).But with the implementation of the national ultra-low emission strategy,this emission concentration will face the risk of non-compliance,therefore,this paper puts forward the proposal of low nitrogen burner transformation,and analyzes the transformation plan,after combining with the SCR gentrification unit,the NOx emission concentra tion of the unit will be reduced to below 50 mg/m~3 to meet the low emission requirements.The results show that:First,After the gentrification system bypass flue transformation,the concentration of NOx can meet the national environmental protection standards,and the denigration unit can operate normally under the whole working condition;Second,renovation project has a good social and economic benefits;Third,after the retrofit of the low nitrogen burner,combined with the existing SCR gentrification unit,the NOx emission concentration will drop below 50 mg/m~3 to meet the low emission requirements.The research of this subject has important guiding significance for the reform of boiler gentrification device in the future.