Stress Engineering Services for Coke Drum Health Monitoring And ...

Stress Engineering Services
April 2001
Stress Engineering Services
for
Coke Drum Health Monitoring
And Reliability Improvement
April 12, 2001
Stress Engineering Services, Inc
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Stress Engineering Services, Inc. is a multi-discipline professional
engineering consulting firm headquartered in Houston, TX with offices in
five major U.S. cities. SES has a staff of more than 130 mechanical,
metallurgical, electrical, chemical, civil and marine engineers with an
average of between 15 and 20 years of practical plant experience.
SES combines this experience with the latest engineering software tools
and materials engineering knowledge to provide “Health Monitoring
Technology” for fixed equipment to assist plant personnel solve daily
engineering problems in an effort to improve plant integrity, safety and
profitability.
SES personnel have extensive coke drum experience in design,
analysis, monitoring, inspection, acoustic emission testing, repair and
life extension of coke drums, including projects for 12 different coke
drum operators on 46 drums where over 1500 coking cycles have been
monitored to date with strain gages and thermocouples including AE
tests on 44 drums during cyclic operation.
SES now provides an unprecedented opportunity to operators of
Delayed Cokers to monitor and improve the “Health” and economics of
reliable coke drum operation.
SES DrumBeat
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Stress Engineering Services
April 2001
SES Engineering Services to Owners,
Operators, and Designers of Delayed Coke
Drums…..
?
Health Monitoring Systems
?
Drum Design and Modeling
? Short and Long Term Strain
Using Actual Operating
Monitoring of Coke Drum
Transients
Response to Daily Operation
?
? Skirt
Cause and Effect of
Operation on Drum Damage
? Shell
? Integration into local DCS
? Piping and Nozzles
?
Defect Identification and
?
Life Assessment and
Assessment
Extension Recommendations
? Acoustic Emission Testing
?
Metallurgical Consulting and
? Inspection Planning &
Testing
Coordination
?
Crack Growth Prediction
? Weld Repair Procedures
?
?
Fracture Mechanics and
Creep Analysis and Omega
Probabilistic Crack Growth
Testing
evaluations using actual
?
Heater Condition and Life
operating data
Assessment
? Low Cycle Fatigue Damage
Accumulation
?
Root Cause Failure Analysis
?
Bulge Analysis
?
Forensic and Litigation
? Severity of bulges and
Support
growth rate
April 12, 2001
Stress Engineering Services, Inc
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The SES Coke Drum team is continuing to expand and develop in
scope and experience. Our team of leading experts include:
Richard Boswell P.E. Mechanical Design, Claudio Allevato ASNT
LIII in Acoustic Emission, Jim Albert P.E. Systems Integration a nd
Bobby Wright P.E., Maintenance. All with over 10 years practical
coke drum experience.
Other key individuals include:
Mechanical
Electrical & Systems Integration
Glenn Aucoin, P.E. Ron Morrison, P.E.
Mac Samman, Ph.D., P.E. Bruce Maughs
Greg Garic, P.E.
Melody May
Materials, Metallurgical and Fracture Mechanics
Bernie Schulze
James Buchannan
Leo Vega
Paul Kovach, P.E. Peter Carter, Ph.D.
Ken Riggs, Ph.D., P.E.
Doug Marriott, Ph.D.
Kim Flesner, P.E.
Civil
Mike Effenberger, P.E.
Chemical
Lori Hasselbring, Ph.D., P.E.
SES DrumBeat
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Stress Engineering Services
April 2001
SES DrumBeat Coke Drum
Structural Health Monitoring Program
April 12, 2001
Stress Engineering Services, Inc
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SES Coke Drum experience has evolved into an organized approach
described as a “Health Monitoring System”. As cycles of drum
operations are collected, the tools to assimilate and evaluate large
volumes of data efficiently has been named SESDrumBeat.
SES’s goal is to build a database so that the effects of daily operation
on drum health can be assessed and understood. Once there is an
improved understanding then a plan for corrective action can be
implemented to Optimize drum operation versus drum reliability
creating “Best Practices” for each refinery and operation.
SES DrumBeat
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Stress Engineering Services
April 2001
Benefits of SES Program to
Coke Drum Operators
? Record and analyze actual measurements from
drum response to daily operation essential to
accurately assess, predict and extend drum Health
? Achieve a better understanding of cause and effect
of operation and processes on drum reliability
? Allow Operators to monitor, improve and
optimize daily operation versus drum damage to
create “Best Practices”
? Make and Save Operators $$$$$$$$$$$$$$$$$$
April 12, 2001
Stress Engineering Services, Inc
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SES is currently building a relational database to store and compare
different operating scenarios versus drum response and damage. From
this database of more than 1500 cycles of strain and temperature data,
we plan to build a “Best Practices” for each location and set of drums
versus different operators, procedures, feed stocks, etc. Eventually, it is
thought that we can create algorithms and procedures from which you
can control drum operation.
SES DrumBeat
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Stress Engineering Services
April 2001
What SES does to improve
Coke Drum Economics and
Reliability:
1.
Install High Temperature Strain Gages,
Thermocouples and Intrinsically safe system to
monitor Shell and Skirt Regions
2.
Hook Intrinsically Safe Logger into Local DCS or
Directly to SES
3.
Retrieve Strain and Process Data routinely
4.
Evaluate trends of recorded strain and damage
versus daily operation: Cause and Effect
5.
Provide Prompt Feedback and Analysis to
Operators to allow for improvement
6.
Provide Engineering Analysis and Support to
Extend Life
April 12, 2001
Stress Engineering Services, Inc
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Coke Drum Operators can improve the reliability of their existing and
new coke drums by having SES install strain gages to monitor the
vessels structural performance versus daily operation. Both the
cylindrical shell and the supporting skirt can be protected through
improved knowledge of consequence resulting from operation of the
drum. SES can tie directly into local DCS making it easier for the
operator to evaluate, control and improve operation.
Transient measurements of actual operating practices can be used as
loading conditions for Finite Element Models to calculate peak stress for
fatigue calculations. This will provide operators with ideal transients and
control parameters for both the shell and skirt regions.
Stress ranges measured for each cycle are used to provide a
probabilistic summation of fatigue damage. This information is used to
assess and predict the progression of cracking and to evaluate the
effects of modified operating practices.
SES DrumBeat
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Stress Engineering Services
April 2001
Temperature distribution soon after Switching
April 12, 2001
Stress Engineering Services, Inc
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SES has been involved with the design and modeling of many new a nd
existing coke drums expanding our knowledge and experience to
compare and evaluate different operating procedures and transients.
From this experience SES can advise on practices and transients to
minimize damage and cracking to improve drum life.
SES DrumBeat
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Stress Engineering Services
April 2001
Skirt is forced outward during Fill transient
April 12, 2001
Stress Engineering Services, Inc
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SES uses the latest FEA modeling software and analysis techniques to
evaluate “actual” measured strain and temperature response to
operation. Experience has shown that design assumptions and reality
are often different, resulting in an overestimated design life. This real
data improves SES’s understanding of drum stresses versus damage
accumulation and the resulting impact of drum life.
SES DrumBeat
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Stress Engineering Services
April 2001
High Temperature Strain Gage
with Intrinsically Safe
Instrumentation
April 12, 2001
Stress Engineering Services, Inc
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SES has designed and built intrinsically safe boxes for the harsh coke
drum environment to house our “Health Monitoring System”. One of
the first SES systems was built and installed in 1997 and is still working
today.
SES routinely installs over 4000 strain gages per year which has
improved our gage installation practices so that we have gages reliably
lasting for a 1 year or more.
SES DrumBeat
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Stress Engineering Services
April 2001
Structural Health Monitoring
Data Processing Tasks
? Review Recorded Data for
– High Temperature Strain Gages
– Thermocouples
? Correct Readings for Temperature Error
? Calculate each pair for Bi-Axial Principal Stress
and Stress Intensity
? Determine Stress Range each Cycle
? Compile Histograms and Damage Accumulation
? Evaluate Process Cause and Structural Effect
? Compare Different Operating Procedures for
resulting Structural Damage
April 12, 2001
Stress Engineering Services, Inc
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These are the fundamental procedures used to process strain gage
measurements into cumulative damage while determining which
aspects of the operations adversely affect drum reliability and could
possibly be modified to enhance the life of the drum and minimize
failures and lost profit.
SES DrumBeat
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Stress Engineering Services
April 2001
Measured Stress is caused by
several conditions
? Measured Stress is
? Stress is composed of
due to
– Average stress in wall :
– Pressure
Membrane
– Gravity and
– Bending Stress
Hydrostatic
inside/outside wall
– Thermal gradients
– Secondary Stress for
– Flattening of Bulges
Geometric Equilibrium
– Solid Coke
– Peak Stress at defects,
Interference
undercuts, weld caps,
radius transition
– Solid Coke Friction
? Stress measurement on
– Ring Bending from
Bulge Diameters
OD is independent of
source of stress
April 12, 2001
Stress Engineering Services, Inc
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By measuring actual drum stress at strategic locations, we can estimate
the rate of damage accumulation from low cycle fatigue for the skirt and
shell. There have been many discussions over the past decade as to
the actual cause of the fatigue stress and bulge formation. These
discussions focus on the role of the hardened coke inside the drum, and
how steam and water flow through it to cool the hot mass: streng th and
permeability are functions of feedstock and process batch procedures.
Consequently, the result is difficult to predict from analysis a lone.
Measurement and interpretation is essential for low cycle fatigue and
fracture mechanics assessments.
In other words, high stress and cracking happens in all drums sooner or
later, the question is can we learn to improve the way we operate the
drums to reduce the rate of damage.
SES DrumBeat
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