The influence of “unsymmetric burning” in a wshaped flame boiler of 600 MW unit at Liaocheng Power Plant upon the combustion performace is camparatively large

the difference of steam temperature

fuel burnout

and NO_x emission under different “unsymmetric burning” condition to be remarkabe. It is believed from analysis that the “unsymmetric burning” is related to many factors

such as: the matching ratio of primary

secondary

and tertiary air; the uniformity and accuracy of air matching; the momentum flow rate ratio of vertical air and horizontal air; the geometric shape of furnace; the error of burners' installed angle; and the designed layout situation of coal pulverizers and burners etc.. The main causes leading to “unsymmetric burning” of said boiler difficultly to be solved are: (1) the momentum flow rate ratio of vertical air and horizontal air to be higher than commonly recommended value

and unproper design of the tertiary air. It is recommended to add one step of tertiary air or to increase the area of tertiary air jet

multiplying the means for correcting “unsymmetric burning” in combustion adjustment.