Simulation Research On Influence Of Air Distribution Mode Adjustment On Boiler Combustion

Traditional energy plans a leading role in energy using in today's era.At the meantime,new energies also develop fast such as wind power,solar energy,biomass energy,etc..But they have not broken through their own limitations.The use of traditional energy sources,remains one of China's largest power generation main force.In the face of China's power demand has not been reduced,coal is still the main primary energy for power generation.So how to improve the efficient use of power plant coal,how to improve the thermal efficiency of the boiler and reducing emissions of nitrogen oxides on the agenda.In view of the above problems,this article takes a200MW tangential-circulating boiler of a power plant as the research object,and first compares and analyzes the effect of the boiler on the emission of nitrogen oxides before and after the transformation.After transformation,then the boiler has been open three different layers of wind in the case of different loads on the thermal efficiency of the boiler and nitrogen oxide emissions do simulation study.The specific researches are as follows:At first,the drawings of boilers are analyzed,which clearly help definite the overall size of the boilers and the modification of the dampers.Some places where they are insignificant for the numerical simulations in the modeling process are omitted.And Y is used for the meshing of the model combustion areas.These effectively reduce the pseudo diffusion in the operation process.Secondly,the boiler is tested in its cold state,and measuring the tangential circle in the furnace and loading the designed value.The model was analyzed by cold simulation so to determine the size of the tangent circle.The actual and theoretical tangent errors are within the controllable range,which verifies the accuracy of the established model.A hot BMCR simulation study was performed based on the boilers before and after the renovation.The comparison before and after the modification of the temperature field,component field,SOFA position and its velocity field at the central section of the furnace,and the nitrogen oxide concentration at the outlet were conducted.Finally,a numerical simulation and experimental study were conducted on the modified boiler with 100%load,75%load and 50%load.Under the same load conditions,by changing the operation number of the coal mill,that is to change the opening number of the tertiary air nozzle,the thermal efficiency of the boiler and the law of the emission of nitrogen oxide were studied.The numerical simulation mainly compared the section temperature field and the concentration field of CO and NO_X in the depth direction and in the position of the tertiary air nozzle.Experimental investigations were carried out on various operating conditions and loads,including the composition analysis of flue gas,slag combustibles and fly ash and determination of the content of nitrogen oxides at the entrance of SCR.Finally,the thermal efficiency of the furnace under different load conditions is calculated by the test data and the formula of thermal efficiency.Through the combination of numerical simulation and experiments,it provides an important reference for the optimization of the air distribution of the four corner tangential boiler and the operation of variable loads.