| 摘要 |
<p>PURPOSE:To lower the generation of NOx, by maintaining the amount of the gas in a furnace constant wherein the amount of air being constantly 25% and reducing the amount of excess air at the operation under low load. CONSTITUTION:The pressure of part of the exit waste gas of an economizer 5 is elevated by a gas recirculating fan 6, and said part is supplied via a flue and a damper 7 to the furnace bottom and is used for controlling the temperature of reheating steam. The secondary combustion air supplied to a burner wind box 11 is supplied via an air duct 12 and a burner wind box inlet damper 13, is whirled and is passed into the furnace 1. The pressure of the gas to be enclosed controls a gas pressure adjusting damper 9 through a control drive 19 by a deviation signal produced by a pressure difference calculator 17 and a proportional integrating arithmetic unit 18 so that the pressures of a pressure transmitter 16 and a pressure transmitter 15 of a secondary air duct 12 may become equal. Thus, at the operation under low load, an amount of excess air to be taken into the boiler outlet waste gas is reduced and therefore the generation of NOx can be reduced.</p> |
