| 摘要 |
PURPOSE:To restrict a volume of nitride oxide generated by a method wherein a bypassing duct not passing in a heat exchanger device is arranged at least either one of the air duct or a discharged gas duct, and a change-over damper for controlling a volume of fluid is arranged in the duct. CONSTITUTION:A bypass duct 8 not passing in a heat exchanger 1 is arranged from a discharging gas duct 3a between the boiler 5 and the heat exchanger 1 to a discharging gas duct 3b between the boiler 5 and the chimney 7. Each of the change-over dampers 9a to 9c is fixed in each of said ducts 3a, 3b and 8. A degree of opening of each of the dampers 9a to 9c is adjusted in a range of operation of high load having a high fuel consumption of the boiler 5 in reference to a volume of nitride oxide in the chimney 7 measured by a concentrometer 10 for nitride oxide and a flow rate of fuel measured by a flow meter 11. Thereby, a volume of combustion air 17 applied for a heat exchanging in the heat exchanger 1 and a volume of discharged gas 16 are controlled, and a volume of the nitride oxide in the chimney 7 is restricted to a value lower than a desired value. |
