Numerical Simulation of Combustion Process of 660 MW Tower Boiler Under Low-O2 Condition at Ultra-Low Load
When the boiler runs under ultra-low load,the excess air coefficient is high,which will lead to a high NOx concentration.In this paper,numerical simulation is used to study the combustion characteristics and NOx emission characteristics of different coal feeding locations under low-O2 conditions.The results indicate that at 50％ and 30％ THA conditions under the same mills operation,the velocity,flue gas species and temperature distribution are similar.The upper feeding locations results in a more uniform and higher distribution of temperature in the main combustion zone,and gradually reduce the imaginary circle radius,enhanced turbulence by counter-tangential air,thus it is advantageous to the combustion stability.During the two mills operation,the concentration of coal powder is larger than three mills,and the combustion temperature in the main combustion area is higher,resulting in more NOx generation.At 30％ THA conditions,the temperature near the ash hopper is higher when the lower mill is running.During low-O2 combustion conditions,the maximum NOx concentration is less than 360 mg/m3.When the load is reduced from 50％ THA to 30％ THA,the NOx concentration at the outlet of the furnace is reduced by 20.8％ .
ultra-low loadtower boilerlow-O2 conditiondifferent coal feeding positioncombustion process
万方数据
维普
