The causes leading to rear platen superheater leakage for boiler no.7 of ultra-supercritical unit in fourth-phase project of Hudian Zhou’xian Power Plant have been analysed

it is believed that the main causes resulting in tube-burst are as follows: blockage of throttle orifice in the inlet of tubes

making the passage section to be reduced

the flow rate of steam to be decreased

the cooling effect to be bad

and the tubes to be overheated. At the same time

the features of pipe blowing technology for the said boiler has been presented.