Burner for combustion of powdered fuel

摘要

A burner for burning pulverulent fuel with combustion air divided into concentric partial flows has a primary-air tube (6) which carries primary air or primary gas and fuel and is surrounded by a secondary-air tube (12) carrying secondary air. The primary-air tube (6) is surrounded by a flow-directing device (26) at the discharge end inside the secondary-air tube (12) while forming an annular gap (25). Secondary air flows through the flow-directing device (26), which is open on both sides and projects beyond the primary-air tube (6) in the axial direction by an amount which corresponds to a value of up to 25% of the outside diameter of the primary-air tube (6). The width of the annular gap (25) is at least equal to 1.5% of the outside diameter of the primary-air tube (6).