Research On Transformation Of The Technique Of Low No_x Burning In Medium And Small Pulverized Coal Fired Boiler

Increasing energy demand, electricity deficiency and increasing dependence onoil importation are among the main energy problems that China is facing today.Energy problem is becoming more and more important. The consumption of coal isincreasing year by year， the combustion of fuels generate more and more NO_xemission, which can lead to serious atmosphere pollution. Until2008, the units under200MW took26%of the total installed capacity of the national thermal power in ourcountry; the pollution from them was serious for the cities. So control the pollution ofpower plant is important for the sustainable development of our country.A Corner-tangential-boiler of160t/h in a thermal power plant was studied in thethesis by means of theory and simulation and field tests, then the low NO_xcombustion modification technologies was researched.Firstly，make sure minimum excess air coefficient of the lord burning zone andcalculate on base of it. And then make out the specific reform plan combining withthe practical experience, and render the drawings of the reconstruction plan. Secondly,use the more extensive numerical calculation software FLUENT to simulate the coldair kinetic, combustion status and NO_xconcentration distribution, providingtheoretical support for real reform. Finally, implement the reform, and test theperformance evaluation after the completion, and check the reform effect.After the reform the NO_xemissions reduced by50%, which had a goodagreement with the simulation results. In addition, it is showed from the simulationresults that the pulverized coal was burned more reasonable because of theredistribution of wind and pulverized coal, which makes the boiler efficiencyincreased by0.88%after reform. Meanwhile the boiler’s economical efficiency wasconsidered, achieving both of the win-win.