After repair of the once-through boiler for supercritical 600 MW unit no.2 in one power plant

over-temperature phenomenon frequently appears on the outlet at A side of platen superheater.It is believed from analysis that the causes of over-temperature may be as follows:the speed of primary air was somewhat larger

the flame centre in furnace was some what higher

the flame temperature at left and right side of furnace had deviation

the ash content of used coal sort was higher than that of designed coal sort

the output capacity of fans at A and B side wasn't uniform

the load was rapidly increased

etc..Regarding to these

some measures

such as optimization of combustion in the boiler

suitably increase the numbers of sootblowing to the water-wall

grind and repair of the cracked spraying tube of desuperheater at A side etc.

have been adopted.After implementation

the steam temperature at A side can be controlled within 540 ℃

the problem of over-temperature at outlet of platen superheater has been efficienly controlled.