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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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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

SES Engineering Services to Owners, Operators, and Designers of Delayed Coke Drums…..

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

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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

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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

TC Apparent Microstrain

Corrected Hoop Microstrain

Axial HTSG

ΔR ΔV Recorded Microstrain

Corrected Axial Microstrain

Hoop Stress

Axial Stress

Delta Stress

Histogram

Fatigue Damage

Crack Propagation Analysis

Stress Range per Cycle

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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