Patent ID: 6024030
Filing Date: 2000-02-15
Classification: F23D

Abstract:
A furnace having side surfaces and corner portions of said side surfaces, said furnace comprising a pulverized fuel burner comprising:a blow box;a plurality of burner nozzles, said burner nozzles having outlet openings for emitting pulverized fuel into the furnace;a plurality of pulverized fuel feed conduits penetrating said blow box and being connected to said burner nozzles, said blow box forming combustion assist air feed paths around said pulverized fuel feed conduits, and each of said pulverized fuel feed conduits having an upstream side, a nozzle side and a bend between said upstream side and said nozzle side;diffusers disposed on one of a) said bend and b) said nozzle side downstream of said bend in said pulverized fuel feed conduits; andrich/lean separators disposed in the vicinity of said outlet openings of said burner nozzles;wherein said blow box comprises a plurality of separate blow box units, and each of said separate blow box units comprises at least one of said plurality of pulverized fuel feed conduits and at least one of said combustion assist air feed paths;wherein said burner nozzles are disposed at said corner portions of said side surfaces;wherein said diffuser has a side edge with a shape, as seen in a cross section in a direction perpendicular to the direction of said pulverized fuel feed conduit, defined by one selected from the group consisting of a polygonal shape and a smoothly curved line, and wherein said pulverized fuel feed conduit has a flow path sectional area that changes along said side edge of said diffuser;wherein said pulverized fuel feed conduit has a flow path direction, and said diffuser further comprises at least one guide plate that extends in said flow path direction at least at said bend portion;wherein said pulverized fuel conduit extends substantially vertically, bending at said bend, and extending through a horizontal portion to an end having a flat nozzle portion forming said burner nozzle, said horizontal portion having an axis, a flow direction being defined in the direction going from said bend portion toward said flat nozzle portion, and said bend portion having an inlet, an outlet, an upper portion and a lower portion;a combustion assist air nozzle located adjacent to a periphery of said flat nozzle portion for feeding the combustion assist air to the periphery of said flat nozzle portion;a pulverized fuel rich/lean separator located along the axis of said horizontal portion of said pulverized fuel conduit, said lean/rich separator having an axis, a cross sectional shape that gradually enlarges in the flow direction and becomes parallel to the flow direction, said rich/lean separator terminating at a flat surface that is perpendicular to the axis of said horizontal portion, and said rich/lean separator having a slit penetrating through said rich/lean separator along the axis; anda kicker block provided at said upper portion of said outlet of said bend portion of said pulverized fuel feed conduit, said kicker block having a surface that is slanted relative to the flow direction.