FINELY POWDERED COAL BURNER AND FINERY POWDERED COAL BOILER, AND METHOD FOR COMBUSTION OF FINELY POWDERED COAL

摘要

PROBLEM TO BE SOLVED: To improve the reduction performance of NOx upon combustion by providing finely powdered coal concentration adjusting means for separating finely powdered coal concentration of a mixed flow of finely powdered coal and primary air in a finely powdered coal infection nozzle such that an outer periphery side is relatively higher than an axial side. ;SOLUTION: An annular particle flow passage adjuster 34 is arranged between a liquid fuel nozzle 5 and a primary air flow passage 30 for changing the size of an internal peripheral wall of a primary air flow passage 30. At a rapid expansion part of the particle flow passage adjuster 34 on the side of a fire furnace a primary air infection flow for conveyance of finely powdered coal and fine particles entrained with the primary air infection flow spread radially and are lowered in their infection speeds. Against this, finely powdered coal particles having relatively larger particle diameters do not spread owing to inertia force so much as the flow of the air without following the flow of the air. Accordingly, the particle flow passage adjuster 34 forms a higher region of finely powdered coal particle concentration on an outer peripheral wall of the primary air flow passage 30 while it forms a lower region of the particle concentration on an internal peripheral wall of the primary air flow passage 30.;COPYRIGHT: (C)1997,JPO