The position of flame centre is an important factor affecting the combustion in W-shaped flame boilers.By using the numerical simulation technology

the combustion in W-shaped flame boiler for a 300 MW unit in one power plant has been calculated under three operating conditions.Through analysis of the temperature field in furnace

the causes resulting in slagging on side walls

the concentration of NOx emission

and the unburned combustibles in fly ash at outlet of the furnace under different operating conditions

it is obtained that the temperature level in the lower furnace rises when the flame centre in the furnace has moved downwards

reducing the pressure drfference between nearby side walls and the central part of the furnace

decreasing significantly the concentration of NOx emission

the unburned combustible content in fly ash at outlet of the furnace being reduced basically in linearity.