TECHNICAL PREPARATION 21
- One size bigger static & dynamic classifier than
offered: Similar benefits as listed for VRM case. We
have observed in recent past that for any up gradation
in VRM, suppliers offer a bigger size classifier saying
that it shall enhance the productivity by 10% or so.
Thereby we analysed this parameter and have asked all
suppliers to offer their mill with at least one size bigger
classifier than their standard. TKIL and FLSmidth has
increased their classifier size after various rounds of
technical discussions - Maximum efficiency of collecting cyclone: This is
also a very important parameter for any grinding system,
as if the efficiency of collecting cyclone increases the
dust load on bag house and its auxiliary equipment
(such as RAL, chain conveyors, hot dust circuit, etc.)
reduces and the power reduction is substantial when
compared to increase in specific power consumption of
raw mill fan. Thereby we have asked suppliers to offer
maximum possible efficiency of collecting cyclones
We had many rounds of discussions with all suppliers to
improve the design aspect and in turn obtaining better
guaranteed parameters. We evaluated both the options
techno-economically, i.e. Vertical Roller Mill and Roller
Press system and then decided to go with Roller Press
system for raw grinding system as it is a heat and power
efficient grinding system with no water spray requirement,
which enables higher potential for power generation at pre-
heater boiler.