Study On SNCR Denitrification Efficiency Of 46MW Reciprocating Grate Hot Water Boiler

At present,China's energy structure is mainly based on the utilization of fossil fuels.By 2019,China's coal consumption accounted for 57.7% of the total consumption.However,whether power generation or heating,boilers are still the most widely used energy conversion equipment.A large amount of nitrogen oxides in the flue gas are not only toxic,but also pollute the environment,which has caused a great impact on people's production and life with great harm.It is more common to burn in the middle layer of industrial boiler,so in this paper we select 46 MW reciprocating grate fired hot water boiler as the research object.And I analyzed the process of combustion and various of factors that can affect the denitration efficiency.In this paper,we analyzed a 46 MW reciprocating grate hot water boiler of a thermal power company.We select the furnace as the research object,simplify other irrelevant structures and then carry out 3D modeling.Then,we use Gambit software to mesh the furnace model,and input the boundary condition data of the boiler operation into fluent numerical simulation software to analyze the combustion and denitration process.Before the numerical simulation,we tested the temperature of the actual running boiler and the concentration of nitrogen oxide at the furnace outlet,and the results were compared with the simulation values.The error value was under12%,and the trend of the test value and the simulation value comes to a similar result.The process of numerical simulation was verified,which provided the reliability of the subsequent simulation results support.For this boiler,SNCR denitration technology scheme is selected,reducing agent is urea solution with concentration of 10%,ammonia nitrogen ratio is 1.4,and each group of spray guns is arranged parallel to the horizontal plane.The control variable method is used to adjust the position,quantity,particle size,angle and velocity of the spray gun,and observe the trend relationship between the change of parameters anddenitration efficiency,ammonia escape.After a comprehensive analysis,the best working condition is obtained.The denitration efficiency can reach 47.8%,ammonia escape is also controlled within 2ppm,and the effect is better than that of NOx concentration at the furnace outlet original condition at 312 ppm.After calculation and simulation,when SNCR is used for denitration of this kind of boiler,the effect is better when the spray gun is set at 7.5m from the middle and upper part of the furnace to the grate;when the number of spray guns is 12,it is moderate,but the number change has little effect on denitration;when the atomization particle size is taken as the middle value of 50-500?m,the denitration efficiency is higher,and the reduction and increase will have different degrees of reduction;when the atomization angle is 30°,the coverage effect is better and the result is better;the injection speed should not be too high,but it may reduce the denitration efficiency when it is higher than 30m/s,and the injection speed should be between 20-30m/s.