During the process of commision debugging of 600 MW supercritical unit no.3 in Datang Xiangtan Power-Generation Co Ltd

problems of unexpected higher main steam temperature had repeatedly appeared.Through analysis

it is believed that the main causes are: small heat load of combustion

low flow rate of steam

low negative pressure in the furnace

low temperature of the feed-water

small deviation of differential pressure between desuperheating water and main steam etc..For these

the adopted measures are as follows:（1） to enhance flow rate of the fuel oil to 8-24 t/h for increasing the heat load of combustion;（2） to control negative pressure in the furnace at-600 Pa

for increasing air flow at the root of oil guns;（3） to control total air flow of the boiler in the range of 500

5

50 km

3

/h for impr

oving the combustion;（4） to enhance the flow rate of feed-water to 410

4

50 t/h

and enhancing the temperature of feed-water to above 90 ℃.After implementation

the problem of unexpected higher main steam temperature during the time of rotation-impulsing has been solved.