Fluid fuel combustion process and turbulent-flow burner for implementing same

Claim 1

Combustion process in which a fluid fuel comprising a pulverized fuel mixed with primary air is injected along an axis, through a burner outlet extended by a frustoconical throat having an upstream end and a downstream end, said fructoconical throat extending outwardly downstream at a half angle of about 10°-35°, injecting secondary air along a helical path around said axis and through the burner outlet, and injecting unheated tertiary air in a ring from a plane defined by said downstream end of said frustoconical throat, downstream and substantially parallel to said axis around the combustible fluid and the secondary air as a substantially circumferentially continuous coaxial cylindrical air jacket laterally confined from outward expansion by a cylindrical, coaxial combustion chamber, said tertiary air being injected as a ring having a diameter between 1.8 and 3.6 times the diameter of the burner outlet, said plane from which said tertiary air is injected being downstream of the burner outlet discharging at a distance between 0.5 and 1.5 times the diameter of the burner outlet, discharging the tertiary air along and adjacent to a refractory material lined confinement wall of said cylindrical combustion chamber, said lined confinement wall extending downstream over a distance between 0.2 and 1 times the diameter of the ring.