| 摘要 |
<p>Method and apparatus for burning dust coal, which are suitably applied to a dust coal-firing boiler. In a conventional dust coal-firing boiler, the concentration of the dust coal in a mixture of dust coal and the air supplied to a burner portion (20) in an initial stage of an operation of the boiler is so low that the mixture cannot be ignited directly by an igniter. Therefore, it is necessary to carry out the precombustion of the mixture by using an auxiliary fuel such as an oil and there is a danger that an explosion should occur in the furnace. According to the present invention, the mixture is circulated in circulation passages (52, 56, 55) to increase the concentration of the dust coal in the mixture which is supplied to a burner portion (20) in an initial stage of an operation of a boiler to a level not lower than a level on which the mixture ignites stably. Accordingly, the mixture can be burnt easily without the need of precombustion using an auxiliary fuel such as an oil, so that there is no danger of any explosion in the furnace.</p> |
