SALIENT TECHNICAL FEATURES OF THE SERVICES

Sub: Contract for overhauling of Unit #2 Milling System2014-15

Introduction: NTPC Talcher-Kaniha plant is located in Kaniha block under Talcher sub-division of Angul district of Orissa.

Nearest Town	: Talcher 26 KMs
Nearest Railway Station	: Talcher 29 KMs
Nearest Airport	: Bhubaneswar 180 KMs
CAPACITY : STAGE - I -		2 X 500 MW - INSTALLED
STAGE- II -		4 X 500 MW - INSTALLED

The plant consists of 2 nos 500 MW units in Stage-I , having Ball and tube mill of Stein Industries France, supplied through BHEL. There are 5 number of mills in each unit.

Technical Feature of the mill:

Forged Steel/Hi-Chrome Ball acts as grinding media in Tube mill. In the Tube mills grinding of coal takes place through attrition The double ended tube mills have two identical coal feeding and outlet circuits but with a common grinding chamber. Horizontal cylindrical mill body lines with wear resistant protective liners supported on two ends rotates on it's axis through train of driving gears. Coal is fed in to mill through two separate raw coal feeders on either ends. Screw conveyors, sometimes called ribbon conveyors are with helical ribbon flights and push the coal into the mill which is filled with grinding media (forged steel/Hi-chrome balls) of different sizes. Mill drum rotation at predetermined speed causes cascade action and tumbling of balls on mill body liners thereby leading to a process of striking and sliding action between the balls and liners but always in the presence of the coal film in between. Continuous cascading due to the slow speed rotation of mill filled with calculated quantity of grinding media turns the raw coal in to pulverized fuel containing coarse and fine particles. This finely grinded particle is blown through fuel piping by hot air to the furnace where it is burnt.