Combustion burner and boiler including the same

摘要

A combustion burner 1 includes a fuel nozzle 2 that injects fuel gas prepared by mixing solid fuel and primary air, secondary air nozzles 3, 4 that inject secondary air from the outer periphery of the fuel nozzle 2, and a flame holder 5 that is arranged in an opening of the fuel nozzle 2. In the combustion burner 1, the flame holder 5 has a splitting shape that widens in the flow direction of the fuel gas. When seen in cross section along a direction in which the flame holder 5 widens, the cross section passing through the central axis of the fuel nozzle 2, a maximum distance h from the central axis of the fuel nozzle 2 to the widened end of the flame holder 5 and an inside diameter r of the opening 21 of the fuel nozzle 2 satisfy h/(r/2)<0.6.

主权项

1. A combustion burner comprising:
a fuel nozzle that injects fuel gas prepared by mixing solid fuel and primary air; a coal secondary air nozzle arranged on an outer side of the fuel nozzle that injects coal secondary air from an outer periphery of the fuel nozzle; a secondary (tertiary) air nozzle arranged on an outer side of the fuel nozzle and the coal secondary air nozzle that injects secondary (tertiary) air to the outer periphery of the combustion flame; and a plurality of flame holders that are arranged in an opening of the fuel nozzle, wherein each flame holder has a structure to cross the opening of the fuel nozzle and a splitting shape that divides the fuel gas in a flow direction of the fuel gas when seen in a cross section along a direction in which the flame holder widens, such that a normal line passing through an apex located upstream of the fuel gas is in parallel to an axial direction of the fuel nozzle, wherein the fuel nozzle, the coal secondary air nozzle and the secondary (tertiary) air nozzle are respectively configured to inject the fuel gas, the coal secondary air and the secondary (tertiary) air in a straight flow which flows in parallel to the axial direction of the fuel nozzle, wherein a plurality of flame holders are arranged to extend through each other at one or more intersections, and wherein at least one intersection is placed in a central area of the opening of the fuel nozzle.