The ZGM 113 type medium speed coal pulverizer boasts technical superiorities

such as low energy consumption

rapid response to load variation

and easy to realize automatic control

etc.

gradually becoming the mainstream auxiliary equipment used for large-capacity thermal power units.But problems existing in practical operation are:large loading pressure

rapid wornout of rollers and lining shoe

serious wornout of the primary air pipe

and high cost in repair and maintenance of equipment.For these

a retrofit scheme has been put forward

including increase of air openings on primary air ring from 36 to 42

decreasing 10% flow-passage area of primary air ring

reducing the loading pressure of the coal pulverizer

adopting new type wear-resisting materials etc..After implementation

the flow velocity in primary air pipe of the coal pulverizer has decreased from 29 m/s to 26.1 m/s

the energy consumption for coal pulverizing being decreased by 1.2 kW·h/t

enhancing remarkably the economic efficiency for coal-pulverizing.