Importance

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Abstract

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.

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First Claim