| 摘要 |
PROBLEM TO BE SOLVED: To provide a vapor temperature control method and control device for a once-through boiler, in which main vapor temperature is controlled in a stable manner even under a great change of load between a sprayed water control loop of a final superheat reduction device and a fuel flow control loop. SOLUTION: The final desuperheater spray water control loop controls the outlet vapor temperature (main vapor temperature) of a final super-heater and the fuel flow control loop controls the front flow side temperature of the final desuperheater device. When heat is apt to be insufficient to lower the vapor temperature, the main vapor temperature is controlled, by the immediately effective desuperheater spray water control loop to be stable. However, the front flow side temperature of final desuperheater falls due to the feature of the once-through boiler that the front flow side temperature at a position where the sprayed water is supplied falls, when the sprayed water is decreased, in addition to a tendency that the temperature falls due to the shortage of heat by a burner. The fuel flow is increased by the fuel flow control loop for controlling it, which can contribute to the substantial recovery of thermal balance and the main vapor temperature can be controlled in a stable manner. When hart is excessive and temperature is a tendency to rise, effects are reverse to the above.
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