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Abstract

A burner especially adapted for use with pulverized fuel slurries, such as pulverized coal-water slurries. The burner has an atomizing nozzle which disperses the slurry in the form of multiple, diverging spray cones issuing from a corresponding number of atomizing orifices. Each orifice is formed by a central atomizing air flow. The slurry is brought into contact with the air flow and is atomized thereby. Before the atomized air flow is discharged, it is enveloped by a rotating auxiliary air flow and constricted to generate a venturi effect which facilitates the formation of the diverging, cone-shaped discharge pattern. A combustion air spinner surrounds the nozzle and is constructed of multiple vanes which have circularly arcuate shapes and a length, in the direction of the air flow, which is least proximate the nozzle and greatest at the periphery of the vanes. This assures an even combustion air flow rate over the entire radial extent of the spinner. The spin rates induced by the blades increase in a radially outward direction by a factor of at least about 10 which generates a pressure gradient downstream of the spinner and radially outward of the burner axis towards which air discharged by the spinner is drawn. This generates a vortex along the burner axis which permits hot combustion gases to penetrate upstream towards the nozzle. Contact between the combustion gases and the nozzle is prevented by the air flow issuing from the spinner in the vicinity of the nozzle. A secondary combustion air envelope is formed by a register which surrounds the spinner and which limits the extent to which the combustion air through the spinner can expand downstream of the burner.

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First Claim