And with a heat recovery unit 104 includes a heat transfer pipe (115) to recover some of the heat of the exhaust gas (G 2), a heat recovery after the exhaust gas (G 3), the electrostatic precipitator 105, which removes the sold-out of the exhaust gas (G 5 ) between the desulfurization device 107 for removing sulfur oxides in the exhaust gas (G 6 ), a reheater 108 provided with a heat transfer tube 115 for heating the exhaust gas G 6, and the heat recovery device 104 and the reheater 108 The heat medium circulation pipe 110 which circulates the heat medium 83 to the heat medium circulation pipe 110, the heat medium heater 86 formed in the heat medium circulation pipe 110 to heat the heat medium 83, and ammonia at the outlet of the denitration device 102 An ammonia-based 200 that detects a state, and a control device 201 that controls the heat medium heater 86 based on the value of the ammonia concentration of the ammonia-based 200 is provided, and the control device 201 includes ammonia. When the concentration is more than a predetermined value, the heat medium 83 is heated by the heat medium heater 86.
展开▼
