| 摘要 |
PURPOSE:To reduce the cost of facility and operating cost and to improve a low Nox state as well as an efficiency of boiler by a method wherein a fine powdered coal burner is arranged at a position above a spreader in a combustion chamber, and both fine powdered coals and air for fine powdered coal combustion less than a theoretical required volume of air are injected from the burner. CONSTITUTION:On the stoker 6, a part of the coal-combustion air B as a surplus air C to be not in use for combustion is generated. The coal A to be supplied to a coal feeder 16 is ground by a mill 17 and made as a fine powdered coal D, fed to the fine powdered coal burner 3 by the fine powdered coal air E passed air E passed from an extrusion air blower 15 through an air heater 11 and branched and fed to the mill 17, then injected into the combustion chamber 4. In this case, the fine powdered coal combustion air E is made less than the theoretical required air volume and the fine powdered coal D is injected under a less volume of air. The fine powdered coal D is ignited together with the fine powder coal air E injected simultaneously and the surplus air C generated on the stoker 6, thereby a reducing zone is generated. Therefore, a low NOx can be attained by this reducing zone.
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