Experimental Study And Numerical Simulation Of Air Staging For A Down-fired Boiler

The latest "thermal power plant air pollutant emission standards," our governmentprovisions more stringent emission standards. It requires that regardless of whenconstruction, tangential boiler NOXemissions in key areas by2015requires less than100mg/m3. Others need less than200mg/m3. So prevention and control of NOXin thethermal power plant become particularly urgent and necessary. But the research aboutreducing NOXemission on down-fired boiler is so scarce. The paper is in accordance withcold water model, cold gas model experiments, numerical simulation method to go on theresearching about the air staging on down-fired boiler.Cold water model system is made according to the relative proportions of the originalboiler that the proportion is1:30. Allocation ways of second wind, inclination of secondwind and OFA situation are researched on the experimental system. OFA cold test bench ismade according to the relative proportions of the original boiler that the proportion is1:15.Different OFA wind rate and different OFA Inclination are researched on the experimentalsystem. Experimental studies show that: in the case of without OFA, the result is wellwhen the allocation way of second wind is that wind velocity of E layer is half of the windvelocity of F layer. Under these conditions above, Inclination angle of secondary airchoosing30°is good. Due to the increasing of OFA wind, the secondary air is weaker. Sothe primary air can reach deeper. Secondary air declination angle can be selected by30°and OFA wind rate are at least20%greater which can make the achieve better primary airJet penetration results. down-dip angle of secondary air can be selected by30°.Numerical calculation is worked by the size of the original boiler with coldexperiment conditions and numerical simulation results and experimental results are ingood agreement. It illustrates the numerical model and calculation method is feasible andeffective. The simulation results show that the good air classifier can make sure has abetter furnace recirculation zone and the flow field mapping. It verifies the experimentalpoint of cold model experiment and has a well relative analysis result.