| 摘要 |
In order that even when by-product gas generated in the production process in a steel plant is used as fuel for mixed fuel burning and the mixed fuel burning ratio increases, an electrostatic precipitator disposed downstream from a denitrification unit can be used, it is unnecessary to increase the pressure resistance strengths of an air pre-heater, a duct and the like which are disposed downstream from the denitrification unit, and thus the increase of the manufacturing cost can be suppressed, disclosed is a boiler (1) provided with a furnace (2), an economizer (3), a denitrification unit (4), and an air pre-heater (5), and configured such that by-product gas generated in a production process in a steel plant, as fuel for mixed fuel burning, can be fed into the furnace (2), said boiler being provided with a bypass duct (11) which bypasses the denitrification unit (4), a bypass damper (12) which is provided midway in the bypass duct, and opens and closes the flow path in the bypass duct (11), and a controller (13) which fully closes the bypass damper (12) when the mixed fuel burning ratio is less than a predetermined value and fully opens the bypass damper (12) when the mixed fuel burning ratio is the predetermined value or more. |
