Riley Stoker Corporation

Donald S Langille

Craig A Penterson

Oliver G Briggs

Francis G Ouellette

A flame retaining nozzle tip for a burner for a pulverized fuel fired furnace receiving a primary stream of pulverized fuel and primary transport and combustion air for discharge into the combustion zone of the furnace comprises a hollow, open-ended, choke or body having an inlet end of generally polygonal flow cross-section for receiving the stream and an outlet end of generally rounded cross-section for accelerating and discharging the stream into the furnace. The outlet end of the choke has a flow cross-sectional area that is less than that of the inlet end to provide choking action. An elongated center element is mounted in coaxial alignment with a central axis of the choke body extending between the inlet and outlet ends. A plurality of swirl vanes are mounted around the central axis and are angularly disposed relative to the general flow direction with inner edges of the vanes spaced equilaterally around and connected to the central element and outer edges connected to the inside surfaces of the choke body. The vanes cause the stream of primary air and pulverized fuel to rotate rapidly around the central axis as the stream passes through the outlet end.

Flame retaining nozzle tip

A furnace, a burner and a method for burning pulverized coal in a highly efficient and precisely controlled manner includes a tubular nozzle with a venturi flow control adjacent the outlet for directing a primary air and coal mixture into a primary combustion zone of the furnace for burning. A coal spreader is mounted in the divergent outlet section of the venturi and swirl vanes on the spreader divide and form the stream into plurality of fuel rich and fuel lean streams discharged into the combustion zone. A tubular conduit in coaxial alignment around the coal nozzle directs a swirling flow of secondary air into the combustion zone around the primary combustion zone and a plurality of tertiary air conduits spaced outwardly of the secondary air conduit are provide to introduce directionally controllable streams of tertiary air into the combustion zone. Each tertiary conduit includes an outlet port for discharging a stream of tertiary air and includes vane means movable to direct the stream of air into or away from the primary combustion zone for improved NO.sub.x control and combustion performance.

Growing community of inventors

Worcester, MA, United States of America

Donald S Langille