| 摘要 |
PURPOSE:To prevent an abnormal temperature rise in heat accumulation before it occurs by discovering by a sensor at an early stage an abnormal state in the change of the temperature in preheating air and in the change of the SOx concentration in exhaust gas. CONSTITUTION:The unburned portion accumulated on the heating elements of an air preheater 1 starts to be oxidized, and when the heat accumalation starts on the elements by the heat generation there, an abnormality appears in an exhaust gas outlet temperature sensor 8 that is provided at exhaust gas outlet section, preheated air outlet temperature sensor 9 provided at the outlet section, and SOx sensor 8 provided at the exhaust gas outlet section, and those temperatures and the SOx concentration start to rise, At this stage at which this abnormality is discovered, a forced draft fan 7 is operated, and if a damper 5 at the outlet of the forced draft fan, damper 6 at the outlet of the preheated air, and damper 3 at the inlet of the air preheater exhaust gas are closed and a partition damper 12 of a bypass duct and an outlet damper 4 of the air preheater exhaust gas are opened, cooling air is sent from a bypass duct 11 for forced cooling and accumulated unburned portion is oxidized and generates heat and the heating elements which are accumulating heat are cooled and an abnormal rise in temperature by heat accumulation on the elements is preveated in the initial stage. |
