Press Release
PAYBACK IN MONTHS FOR TWO LARGE FAN DRIVES
A major upgrading of the control for two large fans has given
both improved throughput and payback in under a year thanks to
substantial energy savings. Two modular Unidrive SPM AC
drives from Control Techniques have produced immediate
energy-savings and paid for themselves in record time.
At Civil and Marine’s Middlesbrough plant, situated on the coast
adjacent to the Corus steelworks, blast furnace slag, otherwise a
waste product from iron production, is ground into a fine powder
called Ground Granulated Blast-furnace Slag (GGBS). This is
used to enhance the properties of concrete, replacing between 20
and 80% of the normal Portland cement.
Excessive wear and tear on dampers in particular prompted an
examination of alternative means of control of the air flow that
extracts the highly abrasive fine powder from the ball mill and
Sepol separator at Civil and Marine’s GGBS grinding plant.
“As neither fan operated at full speed, we also saw an opportunity
for energy-savings”, explains Electrical Engineer and Assistant
Works Manager Rob Thwaites. “We brought in Control Techniques who
calculated likely savings and predicted that the drive for the
Sepol separator would have a payback of just seven months, whilst
the ball mill would pay for itself in nine. The calculations
have proved to be very accurate and we have made precisely the
savings that Control Techniques predicted.”
The Sepol separator is driven by a 200 kW motor running at 71 to
75% of full speed. With the damper, its energy consumption
was 146 kWh. Now, under Inverter drive control, this has been
reduced to 61 kWh, giving a saving of 85 kWh. The roll mill
extract has a 160 kW motor.
The air flow was restricted to 50%, with an energy usage of 105
kWh. This has been reduced to 45kWh, saving 60 kWh on this
machine. The total savings of 145 kWhr, over a 100 hour
production time per week, represent a reduction on the power bill
of over £700 per week – every week!>>>>>>>
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