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HOW TO AVOID DANGER, DAMAGE, AND DOLLARS LOST IN STEAM SYSTEMS
JAMES R. RISKO
President
ABSTRACT
No one wants to experience Danger, Damage or
Dollars lost in a steam system, but common site
management practice often overlooks a critical
component necessary for successful system
performance; maintaining the steam trap population
to original design specifications. Some users may
define necessary steam trap management as just a
focus on the identification and repair of leaking traps
according to a fixed budget. However, this type
approach does not match the criticality of proper
drainage of a steam system to a plant’s successful
operation. Correspondingly, the priority and
implementation of corrective maintenance response
to failures may be reduced to a reactive status,
subordinate to other site maintenance needs.
In such programs, the site may experience
significant - but avoidable safety, reliability,
production, and energy issues. A different priority
and management method – a paradigm shift-to
analyze and improve the relative health of a steam
system is needed. This method focuses on steam trap
population condition threshold values to obtain an
optimized steam system that provides best quality
heat safely and reliably.
Such a paradigm
recommendation has been presented previously (1),
and this paper provides supplemental analyses to
justify the continuous time and monetary investment
required.
CURRENT STRATEGY AND STRUCTURE
Your Steam System
There is only one efficient manner to convey
mass amounts of thermal energy efficiently to a
process application, through a high performance
steam system. A site would not willingly accept low
quality feedstock as a critical component of
production, so why accept poor quality thermal
energy?
When properly designed, steam systems should
be relatively easy to understand the crucial elements
necessary to sustain target production rates. Your
steam system is an important asset (FIGURE 1) that
provides production heat, but commonly sites
unknowingly reduce its value by losing sight of the
importance to drain condensate from the system-and
this can have disastrous effects (4). Basically, there
are two important characteristics to consider for a
TLV CORPORATION
Charlotte, NC
high quality steam system; the supply of dry steam
for turbine, atomizing, flaring, and soot blowing
applications; and the rapid drainage of process heat
exchange equipment to optimize each process
application for production quality, quantity, and
reduced fouling / maintenance issues (8, 9, 11).
(FIGURE 2)
When steam quality is reduced, typically because
the boilers are either pushed to supply steam in in
greater quantity than their rated capacity (sometimes
to overcome steam leaks) - or due to condensate that
has not been effectively removed; then the
condensate that remains causes multiple problems.
Typical examples include water hammer from pooled
condensate that is propelled downstream by high
velocity steam, or stratified/fouled/corroded heat
exchange equipment that experiences stall conditions.
(FIGURE 3)
When the painful events happen to sites with
non-optimized steam systems, employees may come
to expect the amount of incidents as normal, a sort of
necessary burden that befalls all steam systems. In
addition to the above examples, it is common for
plants to suffer critical compressor or flare issues, or
even shutdowns – all caused by condensate that was
not removed effectively. (2, 4). (FIGURE 4)
An existing dilemma is that the correlation of
such a low cost item, a failed steam trap retaining
condensate, to being the cause of a major system
failure or plant shutdown is not often made. Steam
traps are sometimes considered as commodity –
rather than specialty – items, and therefore thought as
having little impact on total plant reliability. It
follows that it is not often considered that having a
steam trap that no longer discharges condensate
(Discharge Failure) can be similar to the effect
putting a rag into the exhaust of an expensive sports
car. The equipment may be worth $ millions, but
without proper and immediate discharge of spent
fluids, it operates poorly and may be damaged.
The metrics that justify managing a trap
population may be wrongly based on recovering
steam loss. Survey database studies reveal that steam
trap populations may have 18% of traps failed in a
leaking mode, while only 13% are failed blocked.
(FIGURE 4)
Proceedings of the Thrity-Seventh Industrial Energy Technology Conference New Orleans, LA. June 2-4, 2015
ESL-IE-15-06-31
It becomes such a simple economic analysis to
determine the return on investment for fixing leaking
steam traps that this practice becomes the priority.
However, the analysis to correlate COLD Failures
from blocked traps requires historical data of prior
incidents and the loss values associated with the
events. Unless there is a proactive program to track
those losses caused by traps that were blocked,
valved-out, or removed; then the causal relationship
of blocked traps to system damage goes either
unnoticed or difficult to valuate. Since the valuation
is difficult, or unknown due to personnel switching
positions, the short-term gain of replacing HOT
Failures (leaking steam traps) is incorrectly given
priority. However, to avoid danger, damage, and
dollars lost – it is best to fix COLD Failures first (1,
4,).
The question of, “Why should the repair of nondischarging traps be given the highest priority?”, is
easily understood by considering the dynamics
causing water hammer in systems that can destroy
piping – particularly at risers and expansion joints.
High velocity steam propels pooled condensate,
particularly dangerous when the piping’s crosssectional area is completely flooded. The results can
be disastrous. (FIGURE 5)
Just as an example of the power and danger, in
one recent instance a petrochemical site experienced
their 24” steam main being moved a distance of about
5’ for a 400’ long section due to water hammer. The
support girders were twisted and the piping was bent
- it was just short of a miracle that the line did not
completely collapse. When the drain taps were
opened, water spewed from the drain for hours. If
the power of rapidly propelled condensate can move
this mass, imagine the effect on turbine blades,
vacuum jets, flare tips, flange gaskets, or steam
nozzles. To prevent these dangerous safety and
reliability events, it is critical to have sufficient
drainage from the system using adequate CDL
(Condensate Discharge Location) drainage points as
shown. (FIGURE 6)
STRATEGIES SHOULD CHANGE?
What Happens After A Survey
A typical state of a trap population may reflect
over 50% of traps failed if the site has not proactively
surveyed and replaced traps on a high priority basis
for the preceding 3-4 years. A worsening effect is
that databases commonly show In-Service traps to
number substantially less than the plant’s original
Design traps total. (GRAPH 1) As trap populations
deteriorate – so does the piping system; and
subsequently destructive incidents occur. Once a
painful event happens, it is common that focus
switches back to the steam trap population – and a
new survey is contracted to learn the current health of
the system. So, it becomes a regular expectation that
when a site renews their focus on steam traps after
years of reactivity; that there will be a substantial
number of the traps failed-and a heavy burden to
repair those traps.
The maintenance, personnel, and economic
burdens on those sites become almost unmanageable.
Consider a site with 4,000 steam trap failures. In
order to bring the site back to 10,000 traps InService, it is necessary to replace 333 traps per
month. This means 3-4 full-time maintenance teams.
How many sites have that much of a labor resource
readily available? (GRAPH 2)
Site management realizes that in order to reach
the target of 10,000 In-Service traps, the existing
failures all have to be repaired. This process is
referred to as “Zero Reset Maintenance” (ZRM®)
(GRAPH 3)
However, the reality of site events is that even if
3-4 response teams were assigned to accomplish
ZRM®, throughout the year they commonly are
pulled off steam trap replacement work (considered
not a high enough priority?) and reassigned to other
repair responsibilities. With lessened effort to fix
failures, the state at the end of the year may show that
there were only 2,004 traps replaced, with 1,996 traps
remaining to be repaired. (GRAPH 4)
It can be a bit embarrassing, having only
completed ~50% of the maintenance work over the
12-month period. This can motivate one of the more
risky actions – to reduce the remaining workload by
simply removing additional traps from service.
Whether from lesser experience or because no critical
damage occurred when some traps were out of
service – some sites justify to remove traps from
service without a proper design analysis to support
the MOC’s required. The thought process might
simply be, “We haven’t experienced and issues – so
those traps aren’t needed!” Such action is a high
concern decision – to overrule the original design of a
Professional Engineering firm – and redesign the
steam system drainage on limited system design
analysis.
What often is not considered is that between the
date of deciding to remove additional traps from
service – and the next time period when traps will be
surveyed with failures replaced – there could be
Proceedings of the Thrity-Seventh Industrial Energy Technology Conference New Orleans, LA. June 2-4, 2015
ESL-IE-15-06-31
additional 1,000 or 2,000 new failures. The general
deterioration of a plant’s steam system under such a
scenario caused the “Good” steam traps to fall under
critical threshold values for safe and reliable
operation – and the total In-Service traps also is
reduced, leaving even a smaller pool of CDL for the
future. (GRAPH 5)
The trend of the “Good” traps state is moving in
the wrong direction in Graph 5 and can never be
trusted to provide safe or reliable operation in a plant.
Eventually, critical thresholds of “Caution”,
“Warning”, and “Danger” are crossed as the plant
becomes less and less sustainable and safe. Unless
there is a fixed minimum threshold of “Good” traps
that must be maintained, the deterioration of the plant
becomes hidden – not to be exposed until a painful
event of Danger, Damage, or Dollars lost is realized.
http://www.tlv.com/global/US/articles/why-badthings-happen-to-good-steam-equipment.html
2. Risko, J. R., “Use Available Data to Lower
System Cost,” Presented at the Industrial Energy
Technology Conference, New Orleans, LA, (May 18,
Session 7, 2011).
www.tlv.com/global/US/articles/use-available-datato-lower-system-cost.html
3. Rossiter, Alan P., “The Four Pillars of Industrial
Energy Efficiency,” Chem. Eng. Progress, pp. 40-44
(May 2015).
4. Risko, J. R., “Beware of the Dangers of Cold
Traps,” Chem. Eng. Progress, pp. 50-53 (Feb 2013).
http://www.tlv.com/global/US/articles/cold-steamtraps.html
A sustainable steam trap population management
program needs to be implemented and maintained
year to year to keep annual failures at a manageable
level (5). This is part of the “4 Pillars of Industrial
Energy Efficiency” (3) needed for sustaining a high
performance steam system. If a site wants to mitigate
risk from problems caused by retained condensate, it
should follow the structure shown that requires
ZRM® each year. This is a proven method to help
maintain effective drainage of the system for optimal
performance and reliability. (GRAPH 6)
5. Walter, J. P., “Implement a Sustainable SteamTrap Management Program,” Chem. Eng. Progress,
pp. 43-49 (Jan 2014).
http://www.tlv.com/global/US/articles/sustainablesteam-trap-management-program.html
EVENTS AND ECONOMICS
7. Risko, James R., 2011. “Understanding Steam
Traps,” Chemical Engineering Progress, New York,
NY, (February, pp. 21 – 26)
www.tlv.com/global/US/articles/understandingsteam-traps.html
Maintenance Budgets Are Fixed And May Be
Insufficient for ZRM®
A fixed maintenance budget is the enemy of
protecting the system and related equipment. Priority
should be established at all cost to make certain a
steam system is adequately drained of condensate
before it can cause damage or waste high value
energy
CONCLUSIONS
Obtaining the necessary budget to maintain a
ZRM® strategy (optimizes “Good” trap total) requires
the support of site management. It is hoped that the
information herein may help validate a request for
funds as needed to obtain a high performance steam
system that optimizes safety and production.
RELATED TOPICS & LITERATURE CITED
1. Risko, James R., “Why Bad Things Happen to
Good Steam Equipment,” Chemical Engineering,
New York, NY, pp. 50 – 58, (March 2015).
6. Russell, Christopher, “Outsourcing Energy
Performance: It’s Potential for Industrial Energy
Efficiency Programs,” American Council for an
Energy-Efficient Economy, Report IE1402, (March
18, 2014)
http://aceee.org/research-report/ie1402
8. “What Causes Stall to Occur,” 2010. TLV Co.,
Ltd., Kakogawa, Japan.
www.tlv.com/global/US/steam-theory/stallphenomenon-pt1
9. Risko, James R., 2006. “Handle Steam More
Intelligently,” Chemical Engineering, New York,
NY, November, pp. 44 - 49.
www.tlv.com/global/US/articles/handle-steam-moreintelligently.html
10. “Steam Trap Losses – What It Costs You,”
2010. TLV Co., Ltd., Kakogawa, Japan.
www.TLV.com/global/US/steam-theory/cost-ofsteam-trap-losses.html
11.
Risko, James R., 2004.
“Steam Heat
Exchangers Are Underworked And Over-surfaced,”
Proceedings of the Thrity-Seventh Industrial Energy Technology Conference New Orleans, LA. June 2-4, 2015
ESL-IE-15-06-31
Chemical Engineering, New York, NY, November,
pp. 58 - 62.
www.tlv.com/global/US//articles/steam-heatexchangers-are-underworked-and-over-surfaced.html
12. Risko, James R., 2007. “Effective Drainage of
Condensing Equipment,” Fluid Controls Institute,
Technical Sheet #ST106, Cleveland, OH, February.
www.fluidcontrolsinstitute.org/pdf/resource/steam/ST106E
ffectiveDrainCondensingEquip.pdf
Risko, James R., 2008. “Steam Traps –
Operating Principles and Types,” Fluid Controls
Institute, Technical Sheet #ST107, Cleveland, OH,
April.
www.fluidcontrolsinstitute.org/pdf/resource/steam/ST10
7OperatingPrinciplesandTypes.pdf
13.
14. “Steam Trap Management System,” 2010.
TLV
Co.,
Ltd.,
Kakogawa,
Japan.
www.tlv.com/global/US/products/070800.html
15. Risko, James R., 2008. “Ask the Experts –
Optimize the Entire Steam System,” Chemical
Engineering Progress, New York, NY, February, p.
32.
www.tlv.com/global/US/articles/optimize-the-entiresteam-system.html
16. “What is Water Hammer,” 2011. TLV Co.,
Ltd., Kakogawa, Japan.
www.tlv.com/global/TI/steam-theory/what-iswaterhammer.html
Proceedings of the Thrity-Seventh Industrial Energy Technology Conference New Orleans, LA. June 2-4, 2015
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Optimize
Steam
OptimizeFigure
Steam1Systems
Systems
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Figure 2
Turbine
Heat Exchanger
Supply Dry Steam
Drain Condensate Fast
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Figure 3
Reduced Productivity
Dangerous Events
From HPAC (Heating/Piping/AirConditioning)
http://www.kirsner.org/kce/media/pdfs/KirsnerHammer.pdf
•
•
•
•
Water hammer
can cause serious
injury or damage
Shutdowns
Uneven heating
Poor quality
Corrosion
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Table 1
Failure(Event(Loss(
Failure(Event(
!
Historical(Value(
!!
Flare(Issues(
Analyzer(Failure(Plant(Shutdown(
Main(Compressor(Failure(
(
$750,000(9($1.7(Mil((
$1(Mil(
$3.6(9($20(Mil(
((
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Figure 4
Steam Trap
FAILURES
COLD
Failure
13%
COLD
Failure
HOT
Failure
18%
HOT
Failure
NO Drainage
COSTLY Drainage
Fix Cold Failures 1st !
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Figure 5
Condensate Slugs Cause Water Hammer!
High Velocity Steam
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st
Figure
6
Priority
11st Priority
1st Priority - REMOVE CONDENSATE!
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Current
State State
of a Trap
Population
Graph
1 - Current
of a Trap
Population
Original Traps
Why This Gap?
In-Service
GOOD
8
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Graph 2 - Failures to Repair
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Graph 3 - Zero Reset Strategy
10
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Graph 4 - Reality
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Graph 5 - Wrong Direction
12
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Graph 6 - Avoid Danger, Damage, & Dollars Lost
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