ValVe Position Monitors offer Harcros cHeMicals an oPPortunity to test... Waters of Wireless aPPlications and iMProVe safety

ValVe Position Monitors offer Harcros cHeMicals an oPPortunity to test... Waters of Wireless aPPlications and iMProVe safety
ValVe Position Monitors offer Harcros cHeMicals an oPPortunity to test tHe
Waters of Wireless aPPlications and iMProVe safety
Wireless Washouts Make Plant Safer
By KeVin root, Harcros cHeMicals
four manufacturing units are situated on about 100
acres at our facility in Kansas city, Kan. our alkoxylation unit
adds ethylene oxide or propylene oxide to produce our t-det
surfactants and other specialty adducts. the surfactants are
shipped in current form or further processed into phosphate
ester surfactants, ether sulfate surfactants or our t-muLZ
emulsifiers. We do about 200 different products at this unit, and
a lot of the products are dissimilar enough that they require
washouts during a changeover.
However, a valve left open after a washout can have dangerous and
expensive consequences.
Primarily, we wanted to minimize employee exposure because we’re
around some pretty severe chemicals. on the environmental side,
Harcros cHemicaLs
FIGURE 1: ONLY ONE WAY OUT
Wireless transmitters were installed on the ethylene oxide
reactor transfer tank. if the valve on the blowdown line were
left open, dangerous chemicals could reach the ground.
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there would be serious issues if these valves were left open and we put
material on the ground. We deal with some dangerous chemicals, so
this could have a severe impact on the environment (figure 1).
TesT The WaTers
in the fall of 2008, Harcros decided to eliminate the risk of an
employee putting a foot in a dangerous chemical spill by dipping its
own toe in the wireless water.
“We put wireless on to verify valve position,” says Lloyd Hale,
director of manufacturing at Harcros. “it was cost-prohibitive to
hardwire because of the locations involved. We’re a batch operation,
so these valves are open after each batch when we do washouts, and
these valves are tough to get to. a person has to reach up through the
piping. We turn reactors around almost every day, so the potential
to miss a valve is always there when you’re dealing with the human
factor, and we needed to verify the valves were closed prior to a
batch. We also wanted to put wireless into a non-critical application
to build our confidence in its reliability.”
a lot of opportunities for wireless applications exist at our site.
before we undertook any major capital improvements, we wanted
to prove the reliability of wireless so we could approach other
applications with confidence.
The only alternative to wireless that Harcros considered was switching
to positive-close, spring-loaded valves that would have to be held
open and then would self-close. “but, during washouts, that would be
hazardous to the employee holding open the valve,” explains Hale.
because a deltaV control system already was in place, Harcros turned
to experitec (www.experitec.com), its local emerson representative.
“We wanted to be sure we could communicate with our current deltaV
system,” explains Hale. “experitec put us in contact with emerson to
evaluate the right valve monitors. We’re at capacity, so we couldn’t shut
the unit down very often. it’s a 5/24 plant, but we normally work every
other weekend. The contractor scheduled its people to come in when
the unit was down. it took about five months.”
ValVe Feedback WiThouT Wires
most process plants have situations similar to Harcros, relates terry
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i eMVPalleuMaetne t
Q4 • 2009
Harcros cHemicaLs
FIGURE 2: BETTER REACH
Wireless transmitters were installed on the reactor’s 3-in. main discharge valve and the
1-in. sample port. The manual valves for sampling, directing, injection and extraction
processes are in hard-to-reach locations.
buzbee, president of the fisher division
at emerson Process management (www.
emersonprocess.com/fisher). “They might
have hundreds or even thousands of valves
that aren’t connected to the control system
because of high wiring costs,” he says. “These
valves therefore provide no feedback on their
actual positions, even though incorrectly
positioned valves represent a significant
cause of safety-related incidents.”
Harcros’ use of manual valves for sampling,
directing, injection and extraction processes
at its facility means many of the valves are in
remote, hard-to-reach locations too costly
to access with wires (figure 2). “monitoring
them was a difficult process, requiring
operators to enter hazardous areas or climb
ladders to check a valve’s state or position,”
adds buzbee.
Harcros installed fisher 4320 wireless
position monitors, integrated with an
emerson smart Wireless gateway and ams
wireless configurators to form a smart
Wireless network communicating with
the site’s existing deltaV system. The selforganizing wireless network passes signals
along to the gateway, creating a redundant
network that bypasses obstructions as
needed. frequent performance updates
occur without any involvement by the user.
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With redundant communication paths,
wireless networks provide reliability between
individual devices and a receiver.
“in the past they had to send someone out
to the valve to check on it,” explains Kurtis
Jensen, fisher instrument product manager
at emerson Process management. “These
valve monitors update every minute. They
know the state of the valves at all times. The
critical periods in production occur after
communications. The only way to get that
today is with a wireless network that builds a
mesh between the wireless gateway and each
and every device. The devices must be able
to reroute communications in case there are
changes or interruptions in the network. The
only network that can do that is WirelessHart.
The 21 devices at Harcros form a mesh and
route traffic to the gateway. most of the devices
communicate directly with the gateway, but
they also formed secondary, tertiary links
between themselves to build the meshing.”
The gateway is connected to the control
room with about a half-mile of fiberoptic
cable, and the antenna for that gateway is on
top of the control room. each device is about
150-200 ft apart, so it’s pretty consolidated.
“The gateway communicates to the deltaV
system 9.3 when installed via modbus
communications,” explains Jensen. “They
recently upgraded to version 10.3 and will
convert to native i/o communications.”
Harcros has several different manufacturers
of valves needing adaptation of the position
monitor. “We have valves from four different
manufacturers and there are different
mounting requirements, even within the same
manufacturer’s valves,” says Hale. “The only
problem we had was with the valve mounting
brackets and covering all the variations. This
took effort and communication, but it was
solved and we moved on. in the end, the
“tHe Wireless Monitor units HelPed us aVoid tHree
product-release incidents, saving at least $75,000.”
they’ve rinsed the reactors and are ready to
fill with the product mixture.” a valve in the
wrong position is the cause of product spills
or a bad product.
Turnkey redundancy
emerson configured everything. When they
left, it was all online and operational, and the
redundancy of the mesh network was critical
to its reliability.
“Harcros, like most, if not all, customers, is
looking to increase confidence in its processes,”
says Jensen. “coming to them with lessthan-reliable products would be a disservice.
of paramount importance is reliability in
network tied into our control system and
came online beautifully.”
The valves are tied into our deltaV
system, but they are not set up as alarms.
“We like to keep them clean,” says Hale.
“When there’s an alarm, it’s a process-critical
alarm. our operators know it requires
immediate attention. The operator would
have to recognize that the valves are in
the closed position and go to the operator
prompt. We still rely on humans to make
sure this process works.”
improVe saFeTy, aVoid cleanup
Harcros has documented numerous benefits
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iMPleMent
Q4 • 2009
from its wireless instrument applications, and
total savings were far beyond the direct cost
reductions of a no-wires installation.
“This was about eliminating mistakes and
increasing safety,” says Hale. “Wireless valveposition monitoring enabled us to reduce
inadvertent emissions and bad batches,
as well as avoid the high costs of rework,
cleanup and lost material. eliminating these
costs—up to $25,000 per incident—is a good
thing for our plant.”
at Harcros, worker safety is a primary
concern, not only because of the location
of the valves, but also because of the toxic
chemicals the valves contain and control,
states Hale. “The facility uses propylene
oxide and ethylene oxide for its processing
operations, and exposure to either one can
irritate a person’s eyes, skin or respiratory
tract,” says Hale. “Leaks involving toxic
chemicals also can result in expensive
fines. adding 21 wireless position monitors
to these isolated, manual valves enabled
Harcros’ personnel to identify inadvertent
emissions before they could result in costly
fines or production delays. The wireless
monitor units helped us avoid three productrelease incidents, saving at least $75,000.”
The FuTure’s so brighT …
besides applying the fisher wireless
position monitors to more of our manual
valves, we’re considering emerson smart
Wireless technology for tank-level
management, rail-car monitoring and a
host of temperature, pressure and flow
applications at our Kansas city site.
as we lose hardwired devices through
attrition, the gateway cost already has
been incurred, so we’re looking to replace
those with wireless devices. The beauty of
wireless is that, as you add instruments, the
system becomes more robust because these
instruments talk to each other. We already
have the wireless units on-plant, and they
should be tied in to the deltaV soon. We also
might be bringing in boiler parameters, other
non-critical valves and some temperature
indication on exchangers to the deltaV.
Kevin root is unit manager at Harcros
chemicals. find out more about Harcros at
www.harcros.com.
Reprinted with permission from Industrial Networking, a supplement to Control Design, Q4 2009. On the Web at
www.industrialnetworking.net. © PUTMAN. All Rights Reserved. Foster Printing Service: 866-879-9144, www.marketingreprints.com.
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