| 摘要 |
PURPOSE:To prevent accidental discharge of NOx, by monitoring NOx content in an exhaust at all times, controlling the air ratio when the NOx value has exceeded a predetermined value, and changing the flow of exhaust to an exhaust gas duct having an NOx eliminator. CONSTITUTION:From the lower part of a furnance side wall are successively arranged a main burner M having an air ratio forming a somewhat incomplete burning region, a sub-burner P forming a burning region with a low air ratio, and an after burner O having an excessive air ratio for combustion. An exhaust gas sampling opening 15 is arranged downstream of an exhaust gas duct 14 for continuously measuring NOx values, and its signal is sent to a control box 17 that compares the stored value with the measured value and issues a command signal to adjust the amounts of air to the burners M, P, O and to control dampers 6, 8a, 8b so that the exhaust gas is flowed via a by-pass duct 8, and therefore accidental discharge of NOx can be prevented. |
