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Types of Stress

•  Stress is composed of –  Average stress in wall : Membrane –  Bending Stress inside/outside wall –  Secondary Stress for Geometric Equilibrium –  Peak Stress at defects, undercuts, weld caps, radius transitions

Stress Engineering Services - CONFIDENTIAL

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Example Coke Drums E and F Strain Gage Instrumentation •  Install Sensors on Drum E and F in Fall of 2001 •  6 Locations per Drum E •  2 Locations Drum F •  Hoop and Axial Strain Gage and 1 Thermocouple at each Location •  Intrinsically Safe Data Logger •  Output all measurements to DCS via Allen Bradley •  SES collected and processed data via dedicated data quality phone line during startup •  SES will reported Stress and Damage relative to Process Results Stress Engineering Services - CONFIDENTIAL

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Drum B

8

Strain Gage PRELIMINARY 7 Locations

6

3

4

5

4

2 3

2

1

1 0-N

90-W

180- S

Stress Engineering Services - CONFIDENTIAL

270-E

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Drum C Strain Gage PRELIMINARY Locations

8

7

6

4

5

3 4

2

3

2

1

1 0-N

90-W

180- S

Stress Engineering Services - CONFIDENTIAL

270-E 4


Coke Drums B and C D

C

B

A

North Data Logger Cabinet

Skirt Deck

Stress Engineering Services - CONFIDENTIAL

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Coke Drum Instrumentation

Structural Column K-Type TC and cable - SES Remote Junction Box-SES Install - client

Hoop and Axial Strain Gages and cable- SES Insulation Remove/Replace With Removable Window 3'X 3'- client Flexible Conduit - client Rigid Conduit and SG/TC cables - client

Data Logger, Purge Control, and Cabinet- SES Skirt Deck 120v instrument power and connect, 2 ground wires - client Instrument Air and connect - client Modem Data Phone Line – client Mount Cabinet & Fabricate support-client Low Purge Alarm Wires to DCS - client Stress Engineering Services - CONFIDENTIAL

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Coke Drums B and C Strain Gage Instrumentation part 1 SES does…

Coker Client does ….

ü Determines where preferred locations are on each Drum

ü Plans location of Remote Junction Boxes so that proper cable lengths can be ordered on the Strain Gages

ü Obtains all sensors ü Obtains all logger equipment ü Assembles the Data Logger with Intrinsic Safety Barriers ü Install Sensors on Drum B and C

ü Remove/Replace Insulation with Removable Window 3'X 3 ü Arrange Fire Watch and Hot Work Permits ü Provides 120 v site electricity for tools, and lighting as needed ü Provide access via scaffold to all areas necessary to install and connect sensors

Stress Engineering Services - CONFIDENTIAL

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Coke Drums B and C Strain Gage Instrumentation part 2 SES does… Coker Client does …. ü Connect Purge Alarm at Control Panel

ü Install Logger Cabinet in any manner they choose on Skirt Deck

ü Install extension wires between SG/TC and Remote Junction box each location

ü Install 2" trunk Conduit to each drum with with ¾" Tee and ¾” Conduit to each Remote Junction Box

ü Connects wires to gages ü Installs Instrument Panel in Logger Cabinet ü Provide Logger Cabinet with Purge Controller, and Remote Junction boxes ü Confirms wire tags ü Connects wires to Panel ü Sets up the Logger and calibrates the gages

ü Install Remote Junction Box (RJB) ü Install hard/flex conduit from RJB to each Location ü Provide and Run all cables in conduit with tags both ends •  For each Location : a 15 conductor Belden, 24 AWG part number B9541 •  For each Location : 1 K type 16 or 18 AWG shielded extension cable ü Install and Connect Power and Air at Logger Cabinet including 2 separate ground sources ü Provide dedicated data quality modem phone line ü Provide and connect Purge Alarm to DCS

Stress Engineering Services - CONFIDENTIAL

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Intrinsically Safe Coke Drum Logger

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2001Drum E : Selected Locations and Gages

×1 (01,02) ×2 (03,04) ×3 (05,06) ×4 (07,08) ×5 (09,10) ×6 (11,12)

Stress Engineering Services - CONFIDENTIAL

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Example Strain Gage Locations

LOCATION # 1 2 3 4 5 6 7 8

HTSG # 1,2 3,4 5,6 7,8 9,10 11,12 13,14 15,16

TC # 1 2 3 4 5 6 7 8

DRUM # E E E E E E F F

CIRC WELD 7 5 4 3 2 1 2 5

HEIGHT ELEVATION DISTANCE ABOVE HEIGHT TO NORTH WELD" 70' 0" 8' 1 51' 0" 23' 2" 23 41' 6" 34' -1 32' 0" 75' 3" 5/8 22' 9.5" 39' 6" 1 13' 7" 29' 1.5 22' 9.5" 20' 1 51' 0" 40' 1

Stress Engineering Services - CONFIDENTIAL

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CSI Logger Software Example

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CSI Software Real Time Display Example

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Analysis of Data •  Review Recorded Data for –  Key thermal parameters –  Process History

•  •  •  • 

Prepare a Data Base of Cycle Characteristics Correlate Process Parameters to Stress Results Identify High Stress and Low Stress Characteristics Compare different ways of operating drum

Stress Engineering Services - CONFIDENTIAL

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DrumBeat Stress Calculation Tasks SES does… 1. 

Obtains data from logger either by direct phone or via client files from DCS.

2. 

Processes using SES DrumBeat algorithms to correct for temperature error, and then calculate biaxial stress. Strains are re-zeroed at start of each cycle.

3. 

Imports to spreadsheets for calculation and plotting, typically 5 cycles per file.

4. 

Determine stress range per cycles.

5. 

Import Process data into file and plot alongside with stress result for comparison.

6. 

Prepare Histograms and trends for stress range.

7. 

Prepare histograms and trends for operating process conditions.

8. 

Calculate fatigue damage using Miners Rule for accumulation.

9. 

Estimate cyclic life for the histogram.

10.  Compare damage between different histograms representing different operating conditions. 11.  Prepare and submit reports monthly. 12.  If data is obtained weekly, report any unusual stress events weekly. Stress Engineering Services - CONFIDENTIAL

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DrumBeat Stress Calculation Tasks Coker Client does… 1. 

Send strain gage, thermocouple, and process data weekly in spreadsheet format from DCS.

2. 

When told of abnormal stresses investigate causes.

3. 

Perform any maintenance for damaged wires or components..

Stress Engineering Services - CONFIDENTIAL

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Key Process Parameters to Record

•  Key Process Data Trend History –  Inlet Temperature –  Outlet Temperature –  Steam Flow Rates –  Water Flow Rate –  Drum Pressure –  Feed Source and Coke Type –  Other ?

Stress Engineering Services - CONFIDENTIAL

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Key Process Parameters to Record

•  Warm Up and Hot Oil Fill Transient –  –  –  –  –  – 

Switch temperature Inlet Temperature Outlet Temperature Length of Pre-warm Length of Fill Max Fill Rate oF/min

•  Filling Drum –  –  –  –  – 

Height of Fill Length of Time for Fill Max Temperatures Duration of abnormal Temperatures Feed Source and Coke Type Stress Engineering Services - CONFIDENTIAL

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Key Process Parameters to Determine

•  Quench Transient –  Max Quench Rate oF/min –  Steam parameters •  •  •  •  • 

Start time End Time Duration Max Rate Total Volume

•  Quench Transient –  Inlet Temperature •  Time between Switch and Steam

–  Outlet Temperature •  •  •  •  • 

–  Water Flow •  •  •  •  • 

Start Time End Time Duration Number of Steps Valve Opening

–  Other Flows

Start time of Cooling End time of Cooling Duration of Cooling Cool Rate Number of Steps

–  Drum Pressure •  Fill •  Quench

–  Max/Min/Range Stresses Stress Engineering Services - CONFIDENTIAL

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Data Processing Tasks

•  Review Recorded Data for –  High Temperature Strain Gages –  Thermocouples

•  Correct Readings for Temperature Error •  Calculate each pair for Bi-Axial Stress and Stress Delta •  Determine Stress Range each Cycle •  Compile Histograms and Damage Accumulation •  Evaluate Process Cause and Structural Effect •  Compare Different Operating Procedures for Structural Damage

Stress Engineering Services - CONFIDENTIAL

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Measured Stress on O.D. of Drum •  Measured Stress is due to –  Pressure –  Gravity and Hydrostatic –  Thermal gradients – Global and Local –  Flattening of Bulges –  Solid Coke Interference –  Solid Coke Friction

•  Stress is composed of –  Average stress in wall : Membrane –  Bending Stress inside/ outside wall –  Secondary Stress for Geometric Equilibrium –  Peak Stress at defects, undercuts, weld caps, radius transitions

Strain Gages Measure Relative Stress on O.D. of Drum From All Sources

Stress Engineering Services - CONFIDENTIAL

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Strain Gage Measurement

•  Strain Gage measures Membrane + Bending on the outer surface •  Strain Gage measures a relative strain as opposed to absolute strain : –  initial ambient strain is Zeroed –  gain set with resistive Shunt Calibration •  Converted Reading = (Gain x Voltage Read) - Zero Offset •  Data Logger uses Remote Sense of Bi-Polar Excitation Pulse at Bridge

Stress Engineering Services - CONFIDENTIAL

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Strain and Stress Calculations

•  Corrected Strain = Measured - Apparent •  Linear Elastic Stress Calculation E = σ / ∈ = Modulus of Elasticity

•  Microstrain = ∈ = micro-inch deformation per original inch of length •  Stress = σ = pounds per square inch •  Bi-Axial Principal Stress : 2 components σa = [Ε / (1-µ2) ] ( ∈a + µ∈h ) σh = [Ε / (1-µ2) ] ( ∈h + µ∈a )

•  Stress Intensity Range as a Stress Difference •  Fatigue Damage calculated as function of Principal and Delta Stress using Miner’s Rule Summation with Range Inputs •  Damage => Cycles till thru wall crack per histogram Stress Engineering Services - CONFIDENTIAL

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2 coke drum applications emision acustica