If the boiler is shutdown and the maintenance period of pressure parts or the shutdown time is within one week, the hot boiler water-discharge drying maintenance should be adopted.
--- Once the boiler bed layer collapses, shut off all the smoke baffles and furnace doors, and close the smoke system.
--- When the drum pressure is reduced to be within 0.5~0.8MPa, the boiler drain door and water-discharging door should be opened to discharge the boiler water as much as possible.
--- When the drum pressure is reduced to be within 0.1~0.2 MPa, the air door on boiler proper should be completely opened.
--- When the boiler water is basically discharged and the bed temperature is reduced to 120℃, the induced draft fan, the high-pressure air fan, the primary air fan and the secondary air fan should be started, the two start-up burner should operate to maintain the fluidized air temperature to be within 220--300℃. Drying with the hot air for 10 to 12 hours, then seal the boiler. And when the outlet smoke temperature of economizer is reduced to below 120℃, the air doors and the drainage doors on boiler proper should be shut off.
--- During the drying and the maintenance process, the relatively air humidity in the boiler should be less than 70% or it should be equal with the environmental relatively humidity.