| 摘要 |
<p>PURPOSE:To enable denitration by increasing an exhaust gas temperature on the upper stream side of a denitrating device to higher than a specified temperature when a boiler load is low or during the starting of a boiler, by a method wherein a bypass duct having a flow rate control damper is positioned to the side of an economizer in a boiler flue duct, and operation of the flow rate control damper is controlled according to an exhaust gas temperature on the upper stream side of the denitrating device. CONSTITUTION:A flow rate control damper 6 is disposed to the inlet part of a bypass duct 5 located to the side of an economizer 4 in a boiler flue duct 1 to allow change of the opening. A signal from an exhaust gas temperature detector 8 on the inlet side of a denitrating device is compared with the denitrating reaction temperature range of the denitrating device, and the opening instruction of the flow rate control damper 6 is inputted to a damper-driving device 7. When a boiler load is low, an actual measurement temperature signal is compared with a set temperature range signal by means of a temperature regulator 9, and when the actual measurement temperature signal is lower than the set temperature lower limit signal, the flow rate control damper 6 is fully opened. When the actual measurement temperature signal is higher than the set temperature lower limit signal and is lower than an upper limit signal, the opening of the damper 6 is properly regulated, and when higher than the upper limit, the damper is fully closed.</p> |
