Coke Drum Strain Gage Installation and Data Processing Stress Engineering Services Examples
Over View of System Data Processing Procedures Stress Results Richard Boswell
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SES Engineering Services to Owners, Operators, and Designers of Delayed Coke Drums….. 4 Health Monitoring Systems
h Short and Long Term Strain Monitoring of Coke Drum Response to Daily Operation h Cause and Effect of Operation on Drum Damage h Integration into local DCS
4 Defect Identification and Assessment h Acoustic Emission Testing h Inspection Planning & Coordination
4 Crack Growth Prediction
h Fracture Mechanics and Probabilistic Crack Growth evaluations using actual operating data h Low Cycle Fatigue Damage Accumulation 4 Bulge Analysis h Severity of bulges and growth rate
4 Drum Design and Modeling Using Actual Operating Transients h Skirt h Shell h Piping and Nozzles
4 Life Assessment and Extension Recommendations 4 Metallurgical Consulting and Testing h Weld Repair Procedures h Creep Analysis and Omega Testing
4 Heater Condition and Life Assessment 4 Root Cause Failure Analysis 4 Forensic and Litigation Support
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Stress Engineering Services Coke Drum Applications
• Low Cycle Fatigue : What to expect • EHMS: Equipment Health Monitoring System • SES DrumBeat Analysis Examples • Other Design Analysis and Measurement Application Examples
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Analysis of Data
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A NOTABLE QUENCH STRESS
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Coke Drums Fail by Low Cycle Fatigue and not by Age Alone
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Coke Drum Failed During Quench : Crack from Inside
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Coke Drum Failed During Quench After Repair
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Typical Girth Cracking Inside Coke Drum
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Crack Growth Scenario
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Example of Coke Drum Cracking
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Example of Probabilistic Crack Growth Calculation
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Radial stress, crack length=1.0 in.,1 hour into fill Stress Engineering Services - CONFIDENTIAL
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Example of Bulged Plates from a Coker
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Coke Drum Remaining Life
• Sections of two drums were replaced and operated safely until replacement in 1 year • Two drums were routinely inspected and repaired on two week schedule in final 3 months Stress Engineering Services, Inc.
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Finite Element Model of Bulged Drum
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Axial Stress Contours Suggest Inspection Points
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OPERATING AXIAL STRESS
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Cracked Skirt to Shell Attachment
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High Temperature Strain Gage is a Platinum Tungsten Sensor rated for 1100 F
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High Temperature Strain Gage: Hoop & Axial w/ TC
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Typical High Temperature Strain Gages with TC
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High Temperature Strain Gage: Hoop & Axial w/ TC
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SES DrumBeat Strain and Stress Calculations Hoop HTSG
ΔR
ΔV
Recorded Microstrain
Apparent Microstrain
TC
Axial HTSG
ΔR
ΔV
Corrected Hoop Microstrain Corrected Axial Microstrain
Recorded Microstrain Hoop Stress
Fatigue Damage Histogram Crack Propagation Analysis
Stress Range per Cycle
Axial Stress Delta Stress
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Measured Stress
• Measured Stress is due to – Pressure – Gravity and Hydrostatic – Thermal gradients – Global and Local – Flattening of Bulges – Solid Coke Interference – Solid Coke Friction
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