Chemical Engineering May 2020 - 50

www.tlv.com/global/us/articles/why-bad-thingshappen-to-good-steam-equipment.html.
58,
2.
Risko, James R., Steam Trap Management: Do Something;
Anything. Please!, Chem. Eng. Prog., October
2017,
pp.
FIGURE 14. Separation promotes high-vacuum
reliability
wetness that should be separated
either at the point of production, or
prior to the first use station (Figure
15) [15].
Desuperheating steam. A desuperheating
system is designed so
that moisture added to superheated
steam lowers the temperature to 10
or 15 degrees above saturation for
the delivered steam pressure. However,
its temperature sensor may be
located in the top of the piping -
unable to determine if the valve is
discharging too much water, which
flows along the bottom of the piping.
Additionally, the sensor may be only
a few feet away from the desuperheating
valve - which can lead to
erroneous readings with high velocity
steam flow. As a result, it is not
uncommon that the desuperheating
flow creates water slugs - which
can be removed by steam traps and
separators for optimal downstream
heating and equipment performance.
Cascading condensate-to-steam
systems. When designers discharge
condensate from a high-pressure
steam line into the next lower steam
pressure, this has the detrimental
effect of increasing the burden on
the steam traps to handle larger
amounts of disentrained condensate.
Additionally, some of that highpressure
condensate mixes with the
lower pressure steam flow - thereby
increasing the wetness of the already
wet steam. In such systems,
mechanical separation can facilitate
improved equipment heating, overall
performance and reliability.
Final remarks
Plant steam is wet, and its suboptimal
quality adversely affects reliable
production and efficiency in multiple
areas. It is not possible to optimize
production with suboptimal steam
quality, but fortunately it can be relatively
easy to improve this important
heat asset.
Plants should establish a maintenance
priority based on the realiza50
FIGURE
15. Waste-heat boilers, steam generators
and flash-recovery installations are examples of
high-wetness equipment that can benefit by using
steam separators
tion that steam traps play an essential
role in the quality of heat used in
the production process. If steam trap
health is ignored or handled on a reactive
basis, the steam system may
not have condensate drained properly,
and this can lead to water hammer
issues, as well as erosion and
catastrophic damage to equipment.
It also increases wetness in the
steam supply, which in turn hinders
process heating operations. Additionally,
determine which heating
equipment, turbines, and vacuum
ejector systems can be enhanced
by using mechanical separators to
disentrain moisture from wet steam,
thereby bringing its quality to near
saturated levels.
Owners investing in capital projects
may want to pay close attention
to the design of new systems
to ensure that appropriate drainage
and separation equipment are
included. Often it is difficult, if not
relatively impossible, to correct a
steam system once it is operating
with lesser quality steam - with
the unfortunate result that expected
benchmark operation cannot be
achieved. Your steam is wet, but it
does not need to remain suboptimal
if you implement suitable measures
to improve its quality.
n
Edited by Gerald Ondrey
Acknowledgements
Special thanks to Jon Walter, Brett Bailey, and Alec
Newell for their proof of the formula to calculate " Ending
Dryness After Moisture Removal. " Thanks also to Drew
Mohr, Justin McFarland, Terrell Moore, and TLV's Global
Marketing Communications Group for creating several
of the graphics contained herein.
References
1. Risko, James R., Why Bad Things Happen to Good
Steam Equipment, Chem. Eng., March 2015, pp. 50-
steam-trap-management.html.
3. Change of State from Ice to Water to Steam Animation:
Introduction to Condensate Recovery, TLV Co., Ltd.,
Kakogawa, Japan, www.tlv.com/global/us/steam-theory/introduction-to-condensate-recovery.html.
4.
The Importance of Steam Dryness Fraction: " Wet Steam
vs. Dry Steam, " TLV Co., Ltd., Kakogawa, Japan, www.tlv.
com/global/us/steam-theory/wet-steam-dry-steam.html.
5. Separators and their Role in the Steam System: Examples
of Condensate Becoming Entrained in Steam, TLV Co.,
Ltd., Kakogawa, Japan, www.tlv.com/global/us/steamtheory/separators.html.
6.
TLV Engineering
Calculator:
Calculator: Superheated
Steam Table, TLV Co., Ltd., Kakogawa, Japan, www.
tlv.com/global/us/calculator/superheated-steam-table.
html.
7. Separators and their Role in the Steam System: Separating
Mechanisms, TLV Co., Ltd., Kakogawa, Japan,
www.tlv.com/global/us/steam-theory/separators.html.
8. Risko, James R., Beware of the Dangers of Cold Traps,
Chem. Eng. Prog., February 2013, pp. 50-53, www.
tlv.com/global/us/articles/cold-steam-traps.html.
9. Risko, James R., " Allocate New Plant Focus to Steam
System Design-Part 1, " Hydrocarbon Processing,
January 2019, pp. 39-43, www.tlv.com/global/us/
articles/plant-focus-on-steam-system-design-pt1.html
10. Avalone, Eugene A. and Baumeister, Theodore III,
" Marks' Standard Handbook for Mechanical Engineers, "
9th Ed., pp. 9-44, McGraw Hill, N.Y., 1987.
11. Lines, James R., R. T. Smith, Ejector System Troubleshooting,
The International Journal of Hydrocarbon
Engineering,
1997, www.graham-mfg.com/usr/pdf/
TechLibVacuum/216.pdf
12. Vacuum Systems: Understanding a Key Component
of a Modern Plant, " Tech Sheet 110, " Heat Exchange
Institute, Cleveland, OH, p 6., www.techstreet.com/hei/
standards/hei-tech-sheet-110?product_id=2002836
13. Birgenheier, David B., T. L. Butzbach, D. E. Bolt, R.
K. Bhatnagar, R. E. Ojala, J. Aglitz, " Designing Steam
Jet Vacuum Systems, Chem. Eng., July 1993 , www.
graham-mfg.com/usr/pdf/techlibvacuum/23.pdf
14. Martin, Gary R., J. R. Lines, S. W. Golden, " Understand
Vacuum-System Fundamentals, Hydrocarbon Processing,
October 1994, www.graham-mfg.com/usr/pdf/
techlibvacuum/210.pdf.
15. Risko, James R., Handle Steam More Intelligently,
Chem. Eng., November, 2006, pp. 44-49, www.tlv.
com/global/us/articles/handle-steam-more-intelligently.html.
Author
James
R. Risko is president of TLV
Corp. (13,901 South Lakes Dr.,
Charlotte, N.C. 29873; Phone: 704597-9070;
Email:
and
condensate
risko@
tlvengineering.com).
The author of
more than 50 articles related to
steam
Risko is active in both the standards
and technical-writing activities of the
Fluid Controls Institute (FCI), and has
previously served as the organization's chairman. He is tasking
with ISO for global steam trap standards, and has earned
three energy-management certifications (CEM, PEM and
NCSU) from the Association of Energy Engineers, N. Carolina
State University and the Institute of Energy Professionals. He
holds an M.B.A from Wilkes University, and two B.S. degrees,
in mathematics/education and business administration/accounting,
from Kutztown University. He created the
" Extended Stall Chart " for heat exchangers, and co-invented
the world's first pump-trap.
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64-72, www.tlv.com/global/us/articles/

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