PULVERIZED COAL FIRED BOILER WITH WALL-ATTACHMENT SECONDARY AIR AND GRID OVERFIRE AIR

摘要

The present invention relates to a pulverized coal fired boiler with wall-attachment secondary air and grid overfire air. Primary burners including primary air spouts, secondary air spouts and close coupled overfire air spouts arranged at intervals along the height direction of a hearth are arranged on four corners of the hearth. Two-way wall-attachment secondary air spouts and one-way wall-attachment secondary air spouts are arranged from bottom to top in a primary combustion zone where the primary burners are located. One-way wall-attachment secondary air spouts are arranged in a reduction zone between the primary burners and the top overfire air spouts, and grid overfire air spouts are arranged in a burnout zone where the overfire air is supplied. By adopting the pulverized coal fired boiler with wall-attachment secondary air and grid overfire air according to the present invention, the NO amount generated in the hearth is reduced, the NO reduction rate along a flame is improved, the coke burnout rate is improved, less coke which is not burnt out enters into the burnout zone, slagging on the water-cooled wall is reduced, and ultralow emission of NOx may be realized on the premise that the combustion efficiency is not reduced, slag is not agglomerated in the hearth and the flue gas temperature deviation is small.