| 摘要 |
PURPOSE:To make it possible to control the temperatures of a primary air at the outlet of a coal pulverizer for a boiler, by by-passing a part of flue gas entering an economizer in the case that coal having high water content is used. CONSTITUTION:When the temperature of primary air at the outlet of a coal pulverizer 17 does not reach a predetermined temperature because of high water content of coal, set temperature of a pulverized-coal primary-air temperature controller 28 is raised. At this moment, a booster fan 23 is actuated so as to supply combustion flue gas by means of a backup gas duct 25; as a result, the temperature of the primary air at the outlet of the pulverizer can be maintained at a predetermined value. When water content of coal becomes still higher, a damper 26a of a by-pass duct 26 for an economizer 3 is opened to raise the flue gas temperature at the inlet of an air preheater 5. Consequently, temperatures of air flowing through a primary air duct 10 is increased and further temperatures of flue gas which is mixed into the primary air from the backup duct 25 can be increased. |
