improved rbi
DESCRIPTION
Improved RbiTRANSCRIPT
Overview
MISTRAS Overview
1
Overview
Improved RBI Analysis of Above Ground
Storage Tanks Through the Use of On
Stream Inspections
Sam Ternowchek
Mistras Group
2
Overview
Internal Inspections of Tank Floors is Expensive
Overview
Inspection Frequency Considerations
a) the nature of the product stored;
b) the results of visual maintenance checks;
c) corrosion allowances and corrosion rates;
d) corrosion prevention systems;
e) conditions at previous inspections;
f) the methods and materials of construction and
repair;
Overview
Inspection Frequency Considerations
g) the location of tanks;
h) the potential risk of air or water pollution;
i) leak detection systems;
j) change in operating mode
k) jurisdictional requirements;
l) changes in service
Overview
Determine Internal Inspection Interval
O
ORRisk Based Inspection
Interval Based on Fixed Time and/or Corrosion Rate
Internal Tank Assessment
Overview
Determined using the corrosion
rate procedures
Or, using the RBI procedures
API 653 Inspection Interval
6.4.2.3
6.4.2.4
Overview
Direct Measurements in API 653: Based on the sum of the product side and soil side bottom corrosion rates
Traditional approach for determining inspection
intervals in API 653
Tends to be a conservative approach because it is
based on the sum of corrosion rates
Inspection Interval Shorter then Necessary
False Sense of Security
Comparison
Overview
RBI Assessment with 10-Year Update Assessments based on API 580/581 as implemented in API 653: Based on direct measurements or conservative-provided estimates of the bottom corrosion rates
Tends to be considered realistic estimates because it is based on the maximum corrosion rate of the bottom
Provides a More Optimal Inspection Intervals
Assessments performed more often
Comparison
Overview
“If an RBI (Risk Based Inspection) assessment has been performed the maximum initial internal interval does not apply to tanks”
An owner/operator can establish the subsequent internal inspection interval using risk based inspection (RBI) procedures in accordance with API RP 580 and the additional requirements of API 653
API 653 Inspection Interval
Overview
The tank design and material of construction
Details about the foundation and surrounding area
Operational history
Inspection history
On Stream Inspections
Product characteristics
Etc.
Factors to Consider in a RBI Assessment
Overview
On Stream Tank Inspections
API 653 In-Service Inspection – Appendix C1.1
Advance NDT Techniques
Acoustic Emission to identify active corrosion on tank floor
Automated UT for corrosion mapping on tank shell (Liquid to
air preferential pitting)
Bulk wave UT for corrosion detection in critical zone
Pulsed Eddy Current and MWM for CUI
Overview
ADVANCE NON-INTRUSIVE SOLUTIONS
TO TANK INSPECTION
Overview
What is Acoustic Emission (AE)
Passive Listening Technique using Piezo Electric
Transducers
Overview
AE AE Sources from Corrosion
•Fracture Decohesion of
precipitation
Metal Dissolution
Thick oxide breakdown
Hydrogen evolution
Corrosion products
spalling
ACOUSTIC
EMISSIONActive Corrosion process
AE Sensor
Overview 16
Overview
Acoustic Sources Detected
Sources of interest:
Spalling of corrosion products.
Leak noise: flow interruption, or turbulence.
Extraneous noise to be removed: Roof and structural movement.
External and pipe-borne noise.
Condensation, particle impacts and valve
leakage.
Overview
Corrosion of Internal Zinc Anodes
• Internal sacrificial anodes
corrode in place on tank
floor.
• Zinc blocks can be large.
• Oilfield production tanks use
sacrificial anodes-very
active when coating has
failed, until zinc used, then
floor corrodes.
Emission from active anodes in a
180 foot diameter tank, 6 ft. x 3 ft. in
size, (30 in tank, 4/10/16)
Overview
Recommendations Matrix“Overall” Grade A B C D E
“PLD” Grade 5 5 2 (2) 1
A 5 5 2 (2) 1
B 4 4 2 2 1
. C 2 2 1 .5 .5
D 2 1 .5 .5 .5
E 1 1 .5 .5 .5
Clearly leaking tanks often unable to grade, (should be opened anyway).
Overview
3-D View of a “Bad” - “E” Grade
and a “Good” “A” Grade
Overview
FOLLOW UP INTERNAL INSPECTION
Overview
What is the Reliability: *
0
20
40
60
80
100
120
A B C D E
FU 1/2 Minimal damage: no repairs FU 3 Damage: some repairs
FU 4 Significant damage: major repair/new floor
Rela
tive
AE-grade
Follow-up results versus AE-grades, normalised per AE-gradepopulation of 157 tanks (Shell, Dow-Stade, DSM,
* P.van de Loo/Shell, B.Hermann/Dow, ECNDT 1998
Overview
Annular Ring UT Inspection
Overview
Long-Range Automated Ultrasonics
(LRUT) Annular Ring Test for Tanks
Gives condition information about critical annular area.
Test with Bulk Wave Ultrasonic
In-service test.
Manual or semi automatic
.
Targets
500m
m
Overview
LRUT Annular Ring Test
LRUT
Inspects critical area, ~20-30 cm.
Automated UT, Plan image.
Detects first edge of corrosion
40 m/day.
Indicative, not quantitative.
SHELL:
PLAN VIEW IMAGE SHOWING
SEVERE UNDERSIDE CORROSION
Overview
Tank Shell Surveys
Slide 27Copyright © 2014 JENTEK Sensors
All Rights Reserved.
MR-MWM-Array
Inspection of Corrosion
Through Protective
Barriers
JENTEK Sensors, Inc. 110-1 Clematis Avenue, Waltham, MA 02453-7013
www.jenteksensors.com
CUI – Corrosion Under Insulation
Slide 28Copyright © 2014 JENTEK Sensors
All Rights Reserved.
h (lift-off)
m(permeability)
MWM sensor
D (Thickness)
Paradigm shift in sensor design (first priority is
predictable response based on physics-based
modeling)
1. Sensors: MR-MWM®-Arrays 2. Next Generation 8200 GridStation®
Electronics
CUI - Technology Summary / Overview
Very low frequencies (deep penetration)
High data rates
Minimal drift
3. GridStation® Software using Hyperlattices™
Rapid, autonomous data analysis
Performs multivariate inverse method
(MIM) using precomputed databases
Defect Images
Performance Diagnostics
Noise Suppression
Real (Re)
Ima
gin
ary
(Im
)
Images
Analysis
MIM
Solve Multiple Unknown Problems
il/4
ScanDirection
Th
ickn
ess
Lif
t-O
ff
Overview
An Example Tank Management Program
“Plant Condition Monitoring Software” - PCMS
29
Overview
Background
• PCMS Captures all operating and design information as it relates to facility tankage
• PCMS evergreens the RBI process per tank circuit, taking into account
• Operating information
• Current corrosion rates
• Historical Inspections
• On Stream Inspections
• API 653 Visual Inspections recorded within PCMS
• Scheduling Flexibility (RBI/Corrosion/Fixed Based Interval)
Overview
TANK RBI SCREENING
• PCMS defines tank damage
mechanisms per mode
• PCMS automatically
screens which damage
mechanisms the tank is
susceptible to.
• PCMS calculates both base
and current Probability of
Failure
Overview
TANK RBI SCHEDULING• PCMS will notify inspector what damage mechanisms to inspect for
• PCMS generates an inspection plan per intrusive/extrusive inspection
types, and effective techniques to use to detect potential damage
mechanisms (customizable)
• User has option to schedule by fixed /corrosion/RBI based intervals
Overview
RBI MATRIX
• Tank circuits are plotted in the
RBI Matrix
• Plotting takes into
consideration POF and COF
(Probability and Consequence of
Failure)
• Consequence values are
configured per facility
• RBI Matrix is customizable
© 2012 MISTRAS GROUP, INC. ALL RIGHTS RESERVED. DISSEMINATION, UNAUTHORIZED USE AND/OR DUPLICATION NOT PERMITTED.
Example - Initial Internal Inspection Interval
Original Design
life > 10 years
25 years max
20 years max
for original High
rank
Risk Assessment
© 2012 MISTRAS GROUP, INC. ALL RIGHTS RESERVED. DISSEMINATION, UNAUTHORIZED USE AND/OR DUPLICATION NOT PERMITTED.
Extensions“Overall” Grade
A B C D E
“PLD” Grade
A 5 5 2 (2) 1
B 4 4 2 2 1
C 2 2 1 .5 .5
D 2 1 .5 .5 .5
E 1 1 .5 .5 .5
Overview
Benefits of RBI
Identify tanks which do not require immediate
internal inspection and repair – Saving MONEY
Determine the condition of damaged floors so that a
correct priority for internal maintenance may be set
Better scope of work when planning tank opening
Reduce down time when out of service
Do the above with little or no disruption to operations
Help prevent tank leakage
Overview
May lengthen or shorten the inspection interval
May result in additional focused inspections
Allows a company to focus its resources
On Stream Inspection Improve the accuracy of RBI
In Conclusion - RBI Assessments
Overview
QUESTIONS ????
