A self-adaptive pulverized-coal fired burner - Design and experimental investigation

The requirements of actual combustion-circle diameter for a tangentially fired boiler and flame center for an opposed wall fired boiler under different loads and the disadvantages of burners presently used by these boilers are reviewed. An adaptive PC-fired burner to loads, which is based on a torsion-spring incorporated damper, is proposed. With the damper installed nearby the burner's exit, the axis of air-jet at the exit can be completely self-adjustable without any other drivers. Therefore, the actual combustion-circle diameter and the flame center can automatically follow variable loads, which will consequently improve ignition, combustion and overall thermal performance. The structure and principle of this burner are introduced. The effects of structural parameters of the burner on angle deflecting characteristics of the damper and that of the jet are experimentally investigated. The results show that the deflected angle of the damper is approximately a linear function of air velocity inside the burner, while the deflected angle of the jet is approximately a linear function of the deflected angle of the damper. These mean that the self-adjustable burner based on a torsion-spring incorporated damper is promising for future application in PC-fired boilers. (C) 2007 Elsevier Ltd. All rights reserved.