| 摘要 |
PURPOSE:To prevent a boiler from tripping, by smoothly changing the source of power to operate the boiler from high viscous fuel to heavy oil when the fuel is emergently cut-off, in the boiler consisting of a plurality of burners, of which main fuel is high viscous one, and heavy oil is used as an auxiliary fuel. CONSTITUTION:Main tubes to feed main fuel, equipped with valves 6a-6d to feed main fuel to burners and check valves 7, and connected to a plurality of burners 14, respectively, are connected to branch tubes to feed heavy oil, respectively, on the downstream side of a check valve 7. These branch tubes are equipped with valves 12a-12d to feed heavy oil to burners and check valves 13, respectively. In a boiler composed in such a manner; first, one of the valves to feed heavy oil, a valve 12d, for instance, is opened, when fuel is emergently cut- off. At the same time, the valves to feed main fuel are closed in the order of 6a 6b 6c 6d, and an operation is continued in the boiler by smoothly changing the source of power from main fuel to heavy oil. In case that the above- mentioned valves 6b-6d are closed, corresponding valves 12b-12d to feed heavy oil to burners are opened in the same order, for the period of a preset time, and afterward, the heavy oil is purged from branch tubes by steam. |
