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Damaging Effects of the Papermaking Process
A fully equipped materials lab is staffed by Emerson technologists who
verify that materials and coatings will perform to expectations.
4 | Fisher
®
Pulp and Paper Solutions
View a video about noise at www.FisherSevereService.com under the
noise video link to the right.
Excessive Noise and Vibration
Noise control is crucial to achieving compliance with
environmental and workplace regulations. High noise levels can
be a serious health risk and can cause hearing damage by reason
of one very loud event, a series of loud events, or days, weeks,
and years of loud noise in a work or recreational environment.
Noise created by cavitation, flowing slurries, steam, or even fluid
leaking past a closed orifice can create an environment that is
unsafe for personnel for extended periods of time.
Regulatory agencies detail the maximum permissible sound
levels and occupational exposure beyond which mitigation
measures and personal protective equipment are required. In the
past, simply presuming hearing protection would be provided
was enough. Today, not providing engineered controls is
deemed an unacceptable work practice.
Designing and incorporating noise mitigation techniques can
include complex procedures, and are often handled as a separate
design discipline. Noise can be found anywhere in a facility or in
a control valve, and must be taken into account. Detailed sound
level predictions are often required during the facility’s design
phase and regulatory compliance sound level measurements are
often required immediately after plant commissioning.
Facility health and safety engineers are employed to pinpoint
noisy processes and equipment, and explore mitigation
techniques to lessen the noise. Emerson design engineers
continually research noise mitigation technologies and bring
Fisher technology solutions to a noisy world.
It is imperative, when working with your Emerson local business
partner or sales office, to review all applications so the best
noise mitigation solutions are appropriately selected for your
applications and assets.
Material Damage
Physical damage to control valves can mean high maintenance
costs, lack of predictability of the damage, and unplanned
shutdown or downtime. Damage can consist of a mechanical
and/or selective chemical nature on material surfaces.
Cavitation damage is a concern in many processes, including
the power and recovery boiler units. This mechanical damage
is characterized by a very irregular, pitted, and rough
appearance. Control valves with extensive damage may have
large amounts of material missing and may severely affect the
valve’s operability. Fisher cavitation solutions help to minimize
cavitation damage and prevent the severity of erosion.
Erosion in a paper mill is also a concern. Erosive slurries including
pulp stock and lime mud can severely erode the internals of
control valves, thus minimizing the service life of the product.
In some cases, the erosion is severe enough to cause pressure
boundary parts to become unstable. This is a safety risk to the
mill. Appropriate material selection is necessary to ensure long-
lasting products and to maximize uptime.
Scaling, also known as fouling, is common in boilers and heat
exchangers operating with hard water that can often result in
lime scale. In addition, scaling can be found in the digester due
to white liquor; the evaporator and concentrator units due to
black liquor; or the recausticizing process due to green liquor
and lime mud. This can cause flow instabilities, increase pressure
drops, induce vibrations that lead to high noise, and a large
number of other unanticipated problems.
Finally, corrosion is prevalent throughout the paper mill. Material
selections are highly important to ensure long-lasting products in
each particular service.
It is important to work with your Emerson local business partner
or sales office to choose the correct products to minimize risk.