SYSTEMATIC APPROACH TO AGEING LNG TERMINALS

1
SYSTEMATIC APPROACH TO AGEING LNG TERMINALS

• March 24, 2004
• OSAKA GAS CO., LTD
• Y. Muro
• T. Ushida

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Contents
1) INTRODUCTION 2) STUDY OUTLINE 3) CASE
STUDY 3-1 Ordinary-temperature Piping 3-2
Concrete Structure 4) CONCLUSION
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1. INTRODUCTION
4
Background
Japan
Tokyo
Pacific Ocean
5
2. STUDY OUTLINE
6
Procedure
Listing of Possible Deterioration
Step 1
Review of Current Management Status
Step 2
Establishment of Management Strategies
Procedure
Step 3
Revision of Maintenance Manuals
Step 4
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Step 1 Listing of Possible Deterioration
Physical Failure Approach
Reference Documents (Past Performance)
Brainstorming
Meetings with Manufacturers
Listing of Possible Deterioration
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Example of Results
9
Step 2Review of Current Management Status
Type of Deterioration (From Step1)
Current Inspection and Maintenance
Comparison
Deterioration Potentials with Inadequate
Management
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Step 34Establishment of Management Strategies

• Maintenance Methods
• Detecting deterioration
• Criteria for evaluating the degree of
  deterioration
• Appropriate inspection frequency

Countermeasures for Deterioration
Revision of Maintenance Manuals
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3. CASE STUDY
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3-1. Ordinary-temperature Piping
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Extraction of Deterioration and Ratings
Interface with Support

• Determine a Rating Based on the Corrosion Mode
• Material characteristics
• Environmental characteristics
• Rating matrix

Evaluation Standards for External Corrosion of
Carbon-Steel Piping
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Rating by Material Conditions
Start
Surface Treatment
No
No
Painting
3
Yes
Yes
No
Good Condition of Painting
No
Insulation
3
1
Yes
Yes
Yes
2
No
Good Condition of Insulation
3
Yes
2
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Rating by Environmental Condition
Start
Wet Condition
Effect of Salty Wind
No
No
A
Yes
Yes
C
Estimate of Wetness
Continuous run/ Intermittent run
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Rating Determination Matrix
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Establishing Optimized Maintenance Methods
Testing and Diagnostic Methods

• Gamma ray inspection
• Rack-through method
• TOFD method

Protective Measures
Determine the Maintenance Method
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Piping Management Methods
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3-2. Concrete Structures
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Mechanism of Deterioration of Concrete
Reinforcing steel doesnt corrode Concrete
is alkaline material
Salt Damage Neutralization
Reinforcing Steel Corrosion
Cracks,Peeling
Decreasing Bearing Force
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Strategy for Approach to Ageing Concrete Structure
1. Visual Survey 2. Detailed Inspection
(20002002)
Concrete Core Sampling
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Example of the Result of Visual Survey
Corrosion of Reinforcing Steel
Cracks
Peeling
Under Surface of a Jetty
Outside Wall of ORV
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Result of the Detailed Inspection
Position at 3cm from Concrete Surface
Amount of Salt(kg/m3)
Depth of Neutralization(mm)
Amount of Salt
Neutralization
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Strategy for Approach to Ageing Concrete Structure
1. Visual Survey 2. Detailed Inspection
(20002002)
Concrete Core Sampling
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Life Cycle Cost Optimization System
Data base function
Design/construction data Inspection
data Repair/Reinforcement data
Life Cycle Cost Optimization System
Proposal of the optimum repair combination
Timings, Methods, Cost Cost
Minimizing

Total Cost of Repair
Salt Amount
Neutralization Depth
Limit State
Limit State
2.5
30
50
Repair
2.0
Repair
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Repair
20
30
1.5
Neutralization Depth (mm)
Amount of Salt(kg/m3)
Life Cycle Cost (Unit)
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1.0
10
10
0.5
0
0
0
2003
2053
2023
2013
2033
2043
2003
2053
2023
2013
2033
2043
2003
2023
2013
2033
2043
2053
Year
Year
Year
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4. CONCLUSION
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CONCLUSION
Ageing Progress
Retention of Reliability
Future
Raising Maintenance Costs
Established Countermeasures play a great role
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END
Thank you very much for your kind attention!
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Rating for Corrosion and Inspection
Frequency
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Gamma ray inspection
Improved Gamma ray inspection (Arrangement ,
Irradiation time ,Film, Image Processing)
Conventional method
Improved method
Imaging screen (Film)
Piping
Piping
Film
Side Support
??
??

• Gamma
• source

Lifting

• Gamma
• source

Inspection spot
Inspection spot
??
????
Supporting structures
Supporting structures
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TOFD(Time of Flight Diffraction) Method
Ultrasonic wave propagation in longitudinal
direction
Healthy Piping
Amplitude
Sending probe
Receiving probe
Ultrasonic wave
Amplitude
Unhealthy Piping
Dumping
Time difference
Sending probe
Receiving probe
Diffusion Time
Corrosion area
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Rack-through Method
Sending receiving probe
Start point
Ultrasonic wave propagation in circumferential
direction
Longitudinal scanning
Piping
Probe
Proof Graph
Piping

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Corrosion rate()
Corrosion spot
10
0
1
2
3
Supporting structures
Echo level(dB)
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Urethane Block Classification
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Measurement Results
Replacement Criteria

• Replacement Criteria
• Icing on bottom surfaces of the urethane block
• Cracking of over 40-50 of perimeter

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Urethane Block Sampling
Insulation
Test piece
Cryogenic piping
Urethane block
Supporting structure
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Replacement Criteria of Cracking
Urethane Block
Urethane Block
Cracking area
Cracking
Assumption
No-Cracking Area 50 of section Area
Cracking length 50 of perimeter
Proportion
Compressive Strength 50 of original
From measurement and reasonable safety factor
Replacement Criteria Cracking
of over 40-50 of perimeter
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Inspection of Corrosion of Reinforcing Steel
Corrosion
Health Condition
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Deterioration Progress of Concrete Structure
Occurring cracks due to rebar corrosion
Deterioration chloride damage or carbonation
Starting rebar corrosion
Duration
Latency period
Develop period
Deterioration period
Performance decrement of the member
Acceleration period
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Process of our maintenance management
START


Maintenance management plan

Immediate response is not needed

Regular visual survey
Regular visual survey

Reviewing of the plan

OK

Eval
uation/judge

Partial repair

NG

Detailed inspection
Deterioration
progress
Detailed inspection


prediction
Evaluation/judge

OK

NG

countermeasure works

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Mechanism of Salt Damage
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Mechanism of Neutralization