POWER January 2012 - 58

Powder river basin coal
Overcoming Fuel-Handling
Challenges
After the initial " rough start " with Units 7
and 8, the MP&W staff instituted a rigorous
process to incorporate the best practices
and technologies in the industry to minimize
problems related to the use of PRB coal. Costello
noted that the three units each had a different
type of combustion technology, which
presented unique operating challenges.
In 1999 when the MP&W staff began converting
Units 7 and 8, they had Tim Korrs, a
6. New dust busters. As part of MP&W's
$5.7 million dust improvement project, more
advanced dust collectors and dustless transfer
chutes were added, which eliminated the
need for several older model dust collectors.
Courtesy: MP&W
B&W representative, come to the plant and do
airflow calculations on the total, secondary,
and primary airflows. As a result of Korrs'
findings, the staff reduced the primary air orifice
in the duct to allow them to run the damper
farther open to help them control primary
air better. Costello said that Korrs " helped us
fine-tune our controls and switched us over
from boiler O2
control to fuel/air ratio control,
which helped us tremendously. "
" Our cyclone-fired boiler was probably the
most challenging, with it having a small fire
box and being a pressurized unit, " he said.
" We added Diamond Power Hydro-Jets to
Unit 9 for additional wall-cleaning capabilities
and a water lance to Unit 8 for additional
upper furnace/screen tube cleaning. "
On the " B " cyclone in Unit 8, the primary
air duct was flush in the secondary air duct. The
MP&W staff had trouble with airflow balance
and then made an elbow on the primary air duct
so that it actually scoops the air out of the secondary
air stream. This modification has also
helped them to achieve a good airflow balance.
Costello added that it takes constant monitoring
with visual boiler inspections by the
operators to keep the boilers operating efficiently
and to prevent any tapping problems.
" Coal tonnage through the cyclone is a big
7. Protection against electrical
hazards. The MP&W staff identified all of
their electrical equipment hazards and developed
the facility's 70E Electrical Protection
Program. The use of decals helps to identify
the personnel protective equipment needed
to safely rack out plant equipment. The staff
also went through the plant and reduced as
many arc flash areas as possible to lower levels,
wherever applicable. Courtesy: MP&W
issue, " he said. " If we can keep it in the 14
tons/hour range we can do pretty well without
gas pilots. It's when we get above that
level and most definitely up in the 17-ton
range that pilots are needed, especially if
burning wet coal or coal that has been on the
stockpile for a while and has lost Btus. "
During the spring 2005 outage, the cyclone
casings were re-skinned. Costello explained
that this action was taken because " we had
been experiencing a lot of burn thrown on
the cyclone skins. " The MP&W staff also increased
the horse power on the drive motors
in the material handling area so the additional
coal tonnage could be fed to the plant.
Dealing with Dust
" Dust control was one of our biggest challenges, "
he said. " We took a six-phase approach
with dust improvement projects
totaling $5.7 million, which were started in
2001 and completed in 2009. Multiple technologies
where utilized in all areas of the
plant's material-handling systems. "
Costello explained that after the plant's initial
changeover to PRB coal, it took several
additional years to implement all of the improvement
projects, from fire protection to coalhandling
chute modifications and replacements.
Other changes involved managing a larger coal
pile, adding dust collectors and dust suppression
systems, and replacing belt skirtings (Figure 6).
Costello also said that the plant had to make
significant changes to its regular housekeeping
58
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duties as a result of the switch to PRB coal.
He emphasized that the staff " cannot leave any
coal dust lying around or accumulating near
coal conveying rollers because PRB coal will
self-ignite if exposed to any heat source. " Conveyor
rooms are washed and swept daily. As
part of the plant's current cleaning regimen,
the operations staff have assigned cleaning areas
throughout the plants.
" Bunker rooms and coal handling out
buildings were not originally designed for
washdown, " he said. " Through the conversion
process, all areas are now hosed down
daily and monitored. "
During any outage in which coal is left in
the bunkers, the bunkers are filled and inerted
with CO2
. As a standard operating procedure,
the MP&W staff does not leave coal in the
bunkers any longer than five days. Costello
said that " the coal is also monitored daily
with a laser temperature gun for hotspots
along with visual inspections. " All bunker
doors are kept closed as well.
Creating a Culture of Achievement
Costello listed the reasons why he thinks the
Muscatine employees are so successful at
carrying out the dual imperatives of efficient
plant operations and workplace safety:
■ Aggressive cleaning schedules at the plant.
■ Use of technology to prevent dust accumulation.
■
Development of a comprehensive combustible
dust management program.
■ Development and implementation of the
National Fire Protection Association's
70E standard for electrical safety in the
workplace (Figure 7).
■ Positive attitudes of all the employees.
■ Overall pride in the plant, evidenced by
the close-knit employees, who typically
are friends, family, and neighbors.
■ A safety culture second to none.
Leading by Example
POWER congratulates the management and
staff of the Muscatine Power & Water plant for
being named the 2011 PRBCUG Small Coal
Plant of the Year. As more facilities follow the
example set by award-winning facilities like the
MP&W plant, the trend toward smarter ways of
handling jobsite risks should produce positive,
long-lasting results for workplace safety.
For further information on the MP&W
plant or the plant's improvement projects,
please contact Mark Costello, maintenance
supervisor, at 563-262-3503 or mcostell@
mpw.org. Additional information on the
PRBCUG and its awards program is available
at www.prbcoals.com. ■
-Angela Neville, JD is POWER's
senior editor.
POWER | January 2012
http://www.prbcoals.com http://www.powermag.com
POWER January 2012

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