| 摘要 |
PROBLEM TO BE SOLVED: To suppress NOx concentration at a low level in the case where an oxygen usage is saved, by comprising an oxygen nozzle for ejecting a high oxygen gas around a fuel nozzle, and comprising air nozzles further outer periphery of the oxygen nozzle. SOLUTION: A fuel nozzle 1 for ejecting fuel is provided at the central portion of an oxygen nozzle 2 to which a high oxygen gas, i.e., pure oxygen or high concentration oxygen is supplied. A plurality of air nozzles 3 are arranged at the outer periphery of the oxygen nozzle 2 in a row with an equal angular interval therebetween. Alternatively, the air nozzle 3 may be arranged around the fuel nozzle 1, and a plurality of the oxygen nozzle 2 may be arranged in a row at the outer periphery thereof. In this case, the high oxygen gas and a combustion air are not mixed in advance but separately ejected. In such a system a nitrogen concentration becomes low in a high oxygen gas for conducting high-temperature combustion, resulting in lowering of an NOx generation rate, which, however, falls short of the NOx effect of the former structure since the surrounding air is in contact with the high-temperature portion. Nonetheless, temperature rise of the fuel nozzle 1 and the inner wall of a combustion cylinder can be suppressed. |
