Effect Of Different OFA Ratio And Height On The Outlet Smoke Temperature Of Pulverized Coal Boiler

China needs numerical coal to support superpower.China's coal industry produced nearly 4billion tons in 2016 and power plant was large proportion of coal proportion,about 60%.Meanwhile,environmental problems which caused by coal are increasingly valued.The most harmful emissions of power plants is nitrogen oxide(NOx)which has most evident impact on the environment and human.So indicator of NOx emissions became the cleaning for power plant emissions leading.The original primary air and secondary wind add fuel is based on the wind is widely used in the world(OFA).Combustion rate of the wind and the geometric location have important influencefor furnace outlet smoke temperature.And the outlet smoke temperature affects for the calculation,economy and efficiency of the boiler operation,which is also an important parameter of design performance.It affects directly for the influence economic safety operation of boiler.There is still no relatively mature way to calculate the smoke temperature at the outlet of furnace.Generally way is on the basis of designer or reform experience and related research is relatively poor.In this paper,it will be based on the real case with means of supercritical boiler combustion rate of the wind and the height of the state to carry on the numerical simulation which is to study the impact of these factors on the furnace outlet smoke temperature with the the OFA ratio and geometric height.Finally corresponding calculation method is discussed in this paper which can provide helpful reference for boiler design or modification.The research will use FLUENT software to simulate the first phase of Zhu Hai power plant600 MW supercritical boiler.It will be based on the boiler namely BMCR condition data with different combustion wind ratio and high position to simulate the whole furnace combustion.After that it will be compared with the actual engineering data and finally find the relationship between the OFA ratio and height.The effect of the relative height of the embers on the export temperature of the furnace is mainly reflected in the separation between the burning embers and the upper burner of the main combustion zone.The final linear regression expression indicates that:the height proportion of OFA have an inflection point.When under the proportion,the outlet temperature and combustion rate of wind state with negative slope linear relationship.When upon the proportion,outlet temperature of the furnace and the combustion rate of the wind state of slope linear relationship.The new coefficient of M is about 0.9 times lower than the old one which means the fuel furnace combustion flame center will be raised after adding the OFA wind.The calculation result shows that the linear regression expression has certain credibility.