Compressed air systems in mining
Compressed air is used for many applications in surface and underground
mines — from exploration to ore processing. In some underground mines,
compressed air is a preferred energy source since is more flexible, reliable
and cost-effective than diesel or electric power.
Compressor challenges (illustrated below)
1. Aging installations are hard to maintain and control, and there’s no
visibility into how each piece of the system is operating, and when a
failure might occur.
2. Compressors are often run unnecessarily, 24 hours a day.
3. Varying air demand occurs throughout the production day.
4. Compressors use a lot of energy — in fact, 70% of a compressor’s cost
is energy.
5. Compressor surge (aerodynamic instability in axial or centrifugal
compressors) results in blade fatigue or even mechanical failure.
6. It’s dicult to match the compressed air supply with system demand.
7. Systems often have air leaks.
8. Excessive pressure drop results in poor system performance and
excessive energy consumption.
Application challenges
Compressed air networks are made
up of several interconnected systems
that each have specific compressed air
requirements and operating schedules.
In some areas of the system, air demand
changes according to mining shifts and
the presence of workers, while other
areas continuously require constant air
supply. The minimum network pressure
can’t drop below the requirements of the
most demanding area.
Rockwell Automation
Mining Solution
Compressed Air System
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Our solutions
Our integrated process control/automation, motor
control and analytics architectures deliver several
benefits across mining operations, including compressed
air systems.
As the core of our mining architectures, RAMS
(Rockwell Automation Mining Solution) delivers dedicated
mining functionalities that are built on standard
PlantPAx® systems:
• Pre-engineered content for control, monitoring
and reporting
• Mining-specific functions,with dedicated control
strategies for compressor controls —
multi-compressor coordinated control and
integrated anti-surge protection
Multi-compressor control
Multi-compressor control significantly improves system
eciency in a distributed compressor system. The
illustration to the right shows the difference that can be
seen before and after applying multi-compressor control.
Our solution delivers centralized master control by
applying optimization algorithms that reduce energy
and maximize equipment output across the compressed
air network.
Power monitoring tools provide information regarding
energy usage. And built-in productivity reports deliver
user-friendly insights about overall compressor system
performance.
Anti-surge control
Anti-surge valves are designed to open within three
seconds of detecting a surge condition to prevent
equipment failure associated with pressure spikes.
Anti-surge valves are effective, but every time a valve is
activated, air is released and consequently energy
is wasted.
Our anti-surge control solution provides a safe and
ecient way to control compressor surge. The solution
is based on an advanced surge control algorithm. Instead
of a universal setpoint, our solution uses a dynamic
setpoint value that is a function of the compressor’s
operating point and surge control line values. The function
understands the flow and pressure ratio associated with
a surge condition — and prevents the compressor from
surging by opening the anti-surge valve.
The surge line is obtained by performing a standard surge
test on the compressor at different inlet valve positions.
The surge points are recorded and interpolated to
generate a precise surge line.
Multi-compressor control
Anti-surge control
Before
08:00 09:00 10:00 11:00 12:00
Air
Flow
After
Air
Flow
08:00 09:00 10:00 11:00 12:00
Inecient
use of the
compressors
Flow requirement
during peak
production
Optimized use
of the combined
compressors