In view of the troublesome problems

such as lower temperature of main and reheat steam

unstable combustion

serious slagging and low ratio of putting automatic controls into operation

encountered on boiler No2 at Yunfu Power Plant

causes are found through analysis

and a scheme of improvement

including reasonable arrangement of Bailey wall

retrofit of burners and ignition oil-guns

speed regulation of pulverized-coal feeder by frequency-coverting technology etc. are put forward. After implementation of said scheme

indices of boiler No2 have reached or closed to the requirements of design

providing a practical example of successfully retrofitting the poor-grade stone-coal fired boilers to solve the commonly existing troublesome problems.