| 摘要 |
PURPOSE:To prevent generation of NOX, by achieving low-load combustion of fuel and lowering the flame temperature by burning fuel at both of primary flame holes and secondary flame holes which are formed in the manner of facing each other in the circumferential direction. CONSTITUTION:Complete combustion of fuel is achieved by feeding primary air at a low rate within the range capable of causing combustion of fuel while controlling the flow rate of air supplied from a primary-air passage 13 by means of an air-flow controlling damper 14, causing combustion of fuel only at primary flame holes 19 in the manner that fuel is not burnt completely at the holes 19 and hence incompletely burnt gas is produced, and producing combustion flame at both of the primary flame holes 19 and secondary flame holes 20 by burning fuel after mixing the incompletely burnt gas with secondary combustion air supplied from the secondary flame holes 20. Thus, since fuel is burnt by use of both of the primary and secondary flame holes 19, 20, the load at the flame holes is reduced. Resultantly, soft combustion flame is produced by way of low- load combustion and the flame temperature is kept at a level lower than 1,000 deg.C, so that the amount of NOX contained in the combustion gas can be reduced considerably. |
