To switch from water level control to superheat degree control smoothly and in a short period of time in the process of starting a once-through heat recovery boiler.
The once-through heat recovery boiler is equipped with an evaporator, a steam separator tank, and a superheater, and includes a water level control function part for controlling the water level in the steam separator tank, and a superheat degree control function part for controlling the superheat degree of outlet steam of the steam separator tank. A control switch operation function part is provided to the once-through heat recovery boiler for controlling a water supply flow rate 87 in a transfer period 8 for performing switching of control from a water level control state 7 to a superheat degree control state 9 during the starting process of the once-through heat recovery boiler. A water supply flow rate control command value of the control switch operation function part is added with a prescribed water supply flow rate decreased portion with respect to a water supply flow rate command value during switching of the water level control by the water level control function part.
MIYAKE MORIJI
UENAKA TADAO
| JP2007315726A | 2007-12-06 |