Solid fuel burner, burning method using the same, combustion apparatus and method of operating the combustion apparatus

Abstract

A solid fuel burner using a low oxygen concentration gas as a transporting gas of a low grade solid fuel such as brown coal or the like and a combustion method using the solid fuel burner are provided. The solid fuel burner comprises a means for accelerating ignition of the fuel and a means for preventing slugging caused by combustion ash from occurring. Mixing of fuel and air inside a fuel nozzleis accelerated by that an additional air nozzleand a separatorfor separating a flow passage are arranged in the fuel nozzle, and the exit of the additional air nozzleis set at a position so as to overlap with the separatorwhen seeing from a direction perpendicular to a burner axis, and additional air is ejected in a direction nearly perpendicular to a flow direction of a fuel jet flowing through the fuel nozzle. An amount of air from the additional air nozzleis varied corresponding to a combustion load. By increasing the amount of air from the additional air nozzleat a low load operation, an oxygen concentration of a circulation flowformed in a downstream portion outside the exit of the fuel nozzleis increased to stably burn the fuel. By decreasing the amount of air from the additional air nozzleat a high load operation, a flame is formed at a position distant from the fuel nozzleto suppress radiant heat received by structures of the solid fuel burner and walls of the furnace.