| 摘要 |
PURPOSE:To reduce the concentration of NOx without increasing the amount of soot contained in exhaust gas, by forming subsidiary fuel injection ports directed toward the region between burner rows where the density of nitrogen oxides is hight in a combustion device having a plurality of burners including main fuel injection ports disposed in a plurality of stages and rows. CONSTITUTION:Although subsidiary injection ports 8 can be formed at either of an upper or lower portion between burner rows 2, 3 and 4, it is preferable to dispose them at a lower position. A mixture consisting of fuel and a small amount of air is ejected from the subsidiary injection ports 8 and produces flames 15, 16 involving reducing radicals while lowering the temperature near the ports 8. At the same time, NOx contained in the combustion gas flowing upward between the burner rows is reduced by the flames 15, 16 through contact therewith, so that the density of NOx is lowered. Although the amount of unburnt substances including reducing radicals is increased, they are burnt further by air supplied from air ports formed on the front side 5 and the rear side 6, so that the amount of soot is not increased. |
