technical NOTES

ƒ Online Condition monitoring to be considered for slow speed HRP bearings
ƒ Magnetic switch shall be considered in return oil line
ƒ Bearings shall be sourced from Europe.
ƒ V-Separator shall be placed above roller press for even material distribution
over roller width and reduction in fines which generate high vibrations.

7.3 Comparative Features of Vertical Roller Mill and Roller Press for Raw Grinding

S. N. Salient Features Roller Press VRM

1 Requirement of hot air Roller press require less

hot gas when material

moisture is low as the

purpose of hot air is only

for drying not for lifting as

in the case of VRM.

Vertical roller mill needs hot

air to dry out the added

moisture in the product

which is required for

maintaining stable bed to

reduce the vibration level.

The hot air is also required

for lifting the material. The

mill is difficult to operate

during kiln shutdown since

it needs hot gas generator

resulting increase in

operating cost

2 Waste heat recovery

system

In case of very little

moisture in the raw

material the hot gas can

be utilized for waste heat

recovery system and in

turn power generation

apprx.2.5 MW

The hot air is completely

utilized even with little

moisture in raw material as

explained above.

3 Power demand Power demand in roller

press system is less hence

will result to less contract

demand.

Power demand in vertical

roller mill system is more

hence it will lead to more

contract demand

4 Erection time

requirement

4 months 7 months