TECHNICAL PREPARATION 23
water spray on table but confirmed that mill would
run at 150 ̊C even with some water spray on table
- Mill internal design: It was discussed with all
grinding OEMs to design the mill internals in such
a way that it operates with better potential capacity,
minimum pressure drop, minimum heat, and
power consumption. We had detailed discussion
on the following internals because it was learnt
from group plants and across industry that people
modify or upgrade below mentioned equipment’s
after few years of operation. If suppliers do these
improvements in advance, we can have advantages
of these from day one and no CAPEX requirement
in future on account of these upgradations:
• Mill table RPM to be as max as possible: A
mill with maximum table RPM increases the table
acceleration which enables mill to have higher
feed on table with same motor load, as retention
time is reduced increasing the potential. But this
parameter was not that critical for our evaluation
as we were evaluating the mill for petcoke grinding
for which anyways we operate mill at reduced
RPM, but if in future we require to grind coal,
then in that case it shall benefit
• Maximum roller surface area to be designed:
As the roller surface area increases, the grinding
coverage area for the same table increases, which
results in increase in effective table area which
