Research On Deep Denitration Technology Of 600MW Coal Fired Unit In Wang Qu Power Plant

As one of the main atmospheric pollutants,NO.is not only an important factor in the formation of acid rain,but also one of the important reasons for the formation of haze.It has attracted more and more attention to the environmental and human hazards.According to investigation,coal combustion is one of the main anthropogenic emissions of nitrogen oxides.The power industry is the main force of coal energy consumption in China,and it is also a big emission of nitrogen oxides.How to effectively control the emission of nitrogen oxides in the large capacity coal-fired power plant has become the key problem of reducing the total emission of atmospheric nitrogen oxides.It is particularly important to study flue gas denitrification technology suitable for large capacity coal-fired units.Although the power industry's air pollution control task is mainly controlled by NOx,some achievements have been made,but there is still much room for improvement and development.At present,there are two most commonly used methods for controlling the mature nitrogen oxide control technology for coal-fired power plant boilers with NOx.The first is to use low nitrogen oxide combustion technology to reduce the content of nitrogen oxides produced by the combustion reaction of coal in the boiler.Specific:1.low NO.combustion technology,2.air graded combustion,3.fuel graded combustion,4.flue gas recirculation,5.thick deviation combustion technology,6.flue gas circulating fluidized bed desulphurization and denitrification technology,and the second removal of nitrogen oxides from flue gas to reduce their external emissions.Specific:1.non catalytic denitrification technology(adsorption,absorption,plasma,selective non catalytic reduction(SNCR),2.catalytic denitrification technology.The 600MW boiler in Wang Qu power plant is a form of single furnace,open air equipment,solid discharge,and front and back wall hedging.The emission concentration of nitrogen oxides is about 600 to 800 mg/Nm3 and 900 mg/Nm3 at different periods when the air grading combustion method is not used before the denitrification technology of 600MW coal-fired power plant in Wang Qu power plant.Based on the goal of efficient and reasonable nitrogen oxide concentration less than 50mg/Nm3,this paper first analyzes the defects and shortcomings of the boiler combustion and the flue gas denitrification in Wang Qu power plant,and puts forward the ideas and suggestions for the design and transformation of the denitrification system,that is to adopt the LNB + SCR two step modification route,first,to stabilize the boiler reaction.On the basis of the degree,the nitrogen oxide concentration is less than 400 mg/Nm3 by the low nitrogen combustion method;second,the use of SCR technology needs to maintain the nitrogen oxide concentration of 500 mg/Nm3 and the overall R&D and analysis operation on the basis of the degree of denitrification maintained at 90%.A numerical simulation analysis was carried out to compare the improvement of denitration data before and after the transformation.Finally,according to the operation status of Wang Qu power plant and the similar operation of other factories,this paper expounds the possible problems from seven aspects,such as the combustion efficiency,the heat balance of the boiler system and the adaptability of the coal,and puts forward some suggestions for selecting the burner with the flame stabilizing equipment.The SCR technology and low nitrogen combustion technology in the furnace are unified so as to promote the normal and orderly development of denitration.