POWER March 2020 - 40

MAINTENANCE BEST PRACTICES
New Technology Improves
Refractory Maintenance and
Shutdown Planning
Power plants require regular maintenance outages to stay in top condition, but shutdown
periods can be stressful. New tools are available that can save time, reduce
labor costs, and improve safety.
Lance Zier
T
he direction of the Environmental
Protection Agency's New Source
Performance Standards (NSPS) is
as uncertain as the direction of the wind,
especially in an election year. Coal- and
gas-fired power facilities can only focus
on factors within their control, and that
includes the efficiency of their scheduled
outages for refractory and insulation repair
and maintenance.
These costs are relatively small. However,
the potential cost efficiencies that
come from using new technologies may
be significant. They include using digital
technologies to create pre-cast refractory
shapes, computer-controlled welding
systems, and digital planning and 3D
modeling tools.
Precast Solutions
Making precast refractory shapes (Figure
1) for burners traditionally requires
fabricating wood or steel forms that take
several days to build. If no blueprints
exist, a team has to make a site visit to
take measurements. Such a manual process
inherently introduces the potential
for human error. Digital solutions can
change that.
2. During the engineering phase of a project, specialty services, such as 3D laser scanning
shown here, help improve accuracy and planning. Courtesy: BrandSafway
Yesterday's tape measure is being
replaced with handheld 3D laser
scanners (Figure 2). They look like
something out of Star Trek but deliver
metrology-grade results. Even when
scanning complex shapes with textured
surfaces, accuracy can be within
a fraction of a millimeter. These tools
can take hundreds of thousands of
measurements in the blink of an eye
and scan complex shapes in seconds
or minutes; this includes burner tiles,
tunnel covers, lintels, peep sights,
and other refractory elements.
Handheld scanners weigh just a
1. Handheld laser scanning systems and
design software enable reverse engineering,
allowing contractors to create any refractory
shape within hours instead of days. Courtesy:
BrandSafway
40
few pounds; a single worker can go
anywhere without lugging support
equipment and take measurements
in far less time than before. Moreover,
the digital file generated can be
easily stored and quickly retrieved,
as opposed to rummaging around a
warehouse to find the right form.
Next, instead of taking the time
to build a steel or wood form, modwww.powermag.com
ern
contractors can create a singleuse
form from expanded polystyrene
(EPS) using a hot-wire CNC (computer
numeric controlled) foam-cutting machine.
Originally developed for signs,
sculptures, and decorative concrete
shapes, hot-wire foam-cutting machines
can produce a form in just a
few hours.
The process starts by feeding
the data from the handheld scanner
into
computer-aided
design
and/or
computer-aided manufacturing (CAD/
CAM) software to create a 3D rendering
and associated cut-path files.
The CNC controls each end of the
hot wire independently, so the fouror
five-axis system can cut complex
shapes.
The work envelope exceeds 12
feet by 9 feet by 4 feet, so shaping
large objects is not a problem either.
While EPS foam forms are single use,
their ease and speed of creation frees
scarce labor for other tasks, such as
POWER | March 2020

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POWER March 2020

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