| 摘要 |
PURPOSE:To enable the use of high caking coal in combination with low caking coal without an increase in an unburnt content, by a method wherein a mill for pulverizing low caking coal is installed separately from a mill for pulverizing high caking coal, and only high caking pulverized coal is supplied to the burner at a lowermost stage of the burners at plural stages of a boiler furnace. CONSTITUTION:High caking coal with button index of 2 or more, which is pulverized by a mill 11, is fed to a burner 4 at a lowermost stage through a fuel pipe 17 by an air fan 16 and is charged into a furnace 1. Meanwhile, low caking and low fuel ratio coal is pulverized by other mill system and is charged through a burner 5 at a middle stage and a burner 6 at an upper stage into the furnace 1. Fire-retardant high caking coal is charged into the burner 4 at the lowermost stage, and this lengthens a residual time in a furnace, improves combustion thereof, prevents increasing of an unburnt content, and enables to perform high-efficient combustion of coal. |
