The originally designed coal sort for boiler no.3 of 300 MW unit in Zhanjiang Power Plant was blend coal of anthracitic coal and lean coal produced from South-east Shanxi Province

it is intended to convert the said boiler to burn bituminous coal

for this

the thermodynamic calculation has been carried out

and the influence of converting the boiler to burn bituminous coal upon safety and economic efficiency of the boiler being analysed.The influence of pulverized coal fineness upon the combustion characters has been studied by using thermo-gravimetric analyser and one-dimentional subsiding furnace.It is determined that the suitable fineness of pulverized coal during trial firing period to be 15%~20%.The retrofit scheme of boiler no.3 has been put forward

and trial firing is carried out.Results show that the boiler can maintain oil-less and stable operation under load of 50%

the thermal efficiency of boiler can be enhanced by 2%.