Effects of the burner arrangement on thermal deviation of 1 000 MW boiler

Abstract:

To solve the problems of ‘cold and hot corners’ and slagging on the hot corners when the burners of dual circle tangential firing single furnace boilers are wall-arranged, an innovated burners arrangement is proposed, and numerical simulation is carried out for a 1 000 MW ultra super-critical lignite boiler with Fluent, to acquire the influence of burner arrangements on the furnace flow field and thermal deviation of heating surfaces at the furnace outlet. The results show that the boiler using a half-wall-half-corner arrangement can effectively improve the form of the tangential flow field, decrease the temperature in the central region of front wall, but it also makes the combustion center higher and the temperature at the platen bottom higher. The increase of the airflow rotation momentum leads to the higher tangential velocity, and makes the airflow fields closer to the side walls. Both the uniformity of the flue gas velocity distributions and the temperature distributions near the furnace outlet sections decrease, but the thermal deviation of heating surfaces at the furnace outlet increase, which can be improved by some methods such as over-fire air deflection.