Various factors affecting the output capacity of MPS-255 medium speed coal mill for boiler no.3 in Yuanbaoshan Power Generation Co Ltd have been analysed. It is believed that the main causes resulting in reduction of the output capacity for said coal mill are as follows: worn-out of the grind rollers

grind tray

nozzle ring

and unreasonable structure of said ring. For these

the grind rollers and grind tray have been replaced

and the fixed nozzle ring being retrofitted into a rotary one. After retrofitting

the output capacity of the said coal mill has been enhanced

ensuring the need of fuel coal for boilers.