Pulverized solid fuel nozzle tip assembly with low contact frame

A pulverized coal nozzle tip assembly adapted for cooperative operation with a pulverized coal pipe nozzle to issue a stream of pulverized coal and air to a coal-fired boiler, comprising:

• an outer nozzle tip portion adapted for mounting in supported relation with the pulverized solid fuel pipe nozzle, the outer nozzle tip portion having an inlet end, an outlet end, and a flow channel extending therethrough from the inlet end to the outlet end, wherein the outer nozzle tip portion includes:
• a pair of opposing lateral sidewalls, each of the opposing lateral sidewalls including a front surface having a contoured profile defining a plurality of spaced recess portions with nose portions formed therebetween;
• a plurality of inset lug plates coupled to the pair of opposing lateral sidewalls, each inset lug plate disposed flush with one of the nose portions in each of the opposing lateral sidewalls;
• and
• a seal frame structure located interior to the pair of opposing lateral sidewalls, the seal frame structure having a top plate and a bottom plate spaced apart from the top plate, both the top plate and the bottom extending horizontally between the pair of opposing lateral sidewalls;
• a monolithic, ceramic, inner nozzle tip portion tiltably secured to the outer nozzle tip portion for longitudinal movement relative to the outer nozzle tip portion, the inner nozzle tip portion having an inlet end, an outlet end, and a flow passageway formed therebetween to receive the stream of pulverized solid fuel and air, wherein the inner nozzle tip portion includes:
• a pair of opposing sidewalls, each of the opposing sidewalls having a back surface with a contoured profile defining a plurality of spaced recess portions with nose portions formed therebetween, the nose portions on the back surfaces of the opposing sidewalls of the inner nozzle tip portion seated correspondingly in the recess portions on the front surfaces of the opposing lateral sidewalls of the outer nozzle tip portion, and the nose portions and the respective inset lug plates on the front surfaces of the opposing lateral sidewalls of the outer nozzle tip portion seated correspondingly in the recess portions on the back surfaces of the sidewalls of the inner nozzle tip portion;
• and
• an air shroud adapted to receive a secondary stream of air, the air shroud having a first plurality of air passages located on the top plate of the seal frame structure, secured between the pair of opposing lateral sidewalls, and a second plurality of air passages located under the bottom plate of the seal frame structure, secured between the pair of opposing lateral sidewalls, both the first plurality of air passages and the second plurality of air passages are adapted to produce different flow pathways for the secondary stream of air.