| 摘要 |
PROBLEM TO BE SOLVED: To narrow a control range of desuperheater spray while improving controllability in main steam temperature control and feed water flow control. SOLUTION: This once-through exhaust heat recovery boiler has a high-pressure once-through system having high-pressure evaporators 17, 18 and high-pressure superheaters 22, 23, has a feed water regulation valve 16 on the feed water system upstream of the high-pressure evaporators, has a spray water control valve 26 in a spray water passage for taking in feed water from the feed water system upstream of the feed water regulation valve, and has a high-pressure overheat desuperheater 25 provided downstream of the spray water control valve to inject spray water to superheated steam. Based on measured flow output from a spray water flowmeter 32 for measuring the spray water amount of the spray water passage, the spray water control valve 26 is controlled so that the spray water amount to the high-pressure overheat desuperheater 25 is a constant value, and based on measured temperature output from an outlet steam temperature meter 24 for measuring the outlet steam temperature of the high-pressure superheater 23, the feed water regulation valve 16 is controlled to control the feed water amount to a high pressure system to thereby hold the outlet steam temperature to a predetermined value below a limit value. COPYRIGHT: (C)2010,JPO&INPIT |
