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Asset Integrity Management
To
Enhance Process Safety
S.K.Bagchi
Addl. Director (Asset Integrity)
Oil Industry Safety Directorate
SIZE OF THE HYDROCARBON INDUSTRY IN INDIA
Total installed refining capacity : ~ 194 MMTPA
Oil production capacity : ~ 38 MMTPA
Gas production capacity : ~ 130 MMSCMD
Gas Pipeline : ~ 14,000 km
Volume of POL handling : ~ 145 MMTPA
Crude & Product pipeline : ~ 26,000 km
ASSETS OF PROCESS PLANTS ARE INHERENTLY
HAZARD PRONE
Assets of process plants are inherently hazard prone
due to the following reasons:
• Large inventory of petroleum products are highly
inflammable;
• Processing at high pressure, temperature;
• Using hazardous chemicals;
• High complexity & process integration;
• Loss of containment results in Fire/Explosion; and,
• History of major incidents in India & abroad
TESRO ANACORTES REFINERY
Date of accident – April 2, 2010
Catastrophic Rupture of Heat Exchanger
Seven Fatalities
TESRO ANACORTES REFINERY
Post-Incident View of D/E/F NHT Heat Exchanger Bank
The naphtha and hydrogen likely auto ignited upon release into the
atmosphere, creating a large fireball.
TESRO ANACORTES REFINERY
The Incident
• Catastrophic Rupture of Heat Exchanger in Catalytic Reformer / Naphtha Hydrotreater Unit.
• Workers were in the final stage of start up activities of A/B/C bank of HE after cleaning. The D/E/F HE remained in service during this operation.
• E exchanger in the middle of D/E/F bank catastrophically ruptured.
• Seven fatalities (1- shift supervisor, 6- operators)
• Highly flammable hydrogen and naphtha at more than 500 deg. F released from the ruptured HE
• The naphtha and hydrogen auto ignited upon release into atmosphere.
TESRO ANACORTES REFINERY
Key Findings
• The CS HE shell failed due to High Temperature Hydrogen Attack
(HTHA).
• API 941- Nelson curve: Cr-Mo steel & SS better & safe material than
CS
• The welds of exchanger shell were not post weld heat treated.
• Rupture took place in the unclad portion of pressure containing shell.
• Tesoro did not monitor actual operating conditions of the B and E
exchangers
• Inspection for HTHA is very difficult. It may be microscopic and may
be present in small localised area. Specific technique and skill of the
inspector is required. This is a difficult inspection challenge.
TESRO ANACORTES REFINERY
Example of Fouling Deposits on the Inside of Heat Exchanger
Tubes. Fouling greatly reduces heat transfer between the shell-
side and tube-side process fluids.
TESRO ANACORTES REFINERY
Lesson Learnt:
• Inherently safe material (Cr-Mo steel & SS) could have prevented the
Heat Exchanger shell rupture. (Design)
• Monitoring of actual operating conditions of the B and E exchangers
should have been done. (Production)
• HTHA was not identified by Inspection. (Inspection)
• Repair / replacement of damaged shell of heat exchanger due to
HTHA was not carried out. (Maintenance)
• Difficult inspection challenge to identify HTHA (Inspection)
ASSET INTEGRITY MANAGEMENT SYSTEM
Key components:
• Design, fabricate and install all facilities and equipment in
accordance with applicable industry codes and recognised
best practices.
• Operate facilities and equipment within design tolerances
and within the safe operating envelope.
• Routinely inspect and maintain equipment in accordance
with industry codes and recognised practices, including
manufacturer recommendations where appropriate.
• Analyse equipment failures to determine their cause.
ASSET INTEGRITY MANAGEMENT SYSTEM
• Conduct all related tasks using trained and qualified
individuals who use approved procedure and complete the
tasks as scheduled.
• Use high quality parts and materials, including a system for
positive material identification (PMI).
• Maintain an equipment archive with up to date equipment
history.
• Safely dismantle and dispose of the facility at the end of its
life cycle.
A systematic implementation of the above will help in
preventing accidents.
COMMON CAUSES OF INCIDENTS
Maintenance, Inspection Related-
• Not adhering to PMS schedule
• Delay in handing equipment for Inspection
• Overstretching equipment run
• Postponement of Tank M&I & Annual Turnaround schedule
• Mechanical seal failures
• Improper maintenance practices
• Impaired safety critical items for long time
• Integrity of flame proof fittings not maintained
• Not undertaking proper inspection upon repair
RISK BASED INSPECTION
What is RBI-
• RBI is a method for using Risk as a basis for prioritising and managing the efforts of an inspection program.
• In an operating plant, a relatively large percentage of the risk is associated with a small percentage of equipment items.
• These potential high-risk components can require greater attention through a revised inspection plan
• RBI permits the shift of Inspection & Maintenance resources to provide a higher level of coverage on the high risk items and an appropriate effort on lower risk equipment.
PROBABILITY
CONSEQUENCE
RISK
INTERNAL
CORROSION
EXTERNAL
CORROSION CRACKING
& OTHERS
Release of flammable/ Toxic material Release of
excessive pressure
Environment
damage Production
loss
RISK ANALYSIS
MANAGING ACCEPTABLE RISK
INSPECTION COSTS (level of inspection activities)
R
I S
K
Risk Using RBI
Risk with Typical Inspection Program
Risk Based Inspection
Uninspectable Risk
MULTIDISCIPLINARY TEAM
inspector
corrosion engineer operator
maintenance
process engineer
inspector
corrosion engineer operator
maintenance
process engineer
Benefits from RBI Implementation
• Optimise Inspection expenditure by focussing on high risk items
and employ most appropriate inspection technique to reduce
operating risk.
• Extension of turn around interval
• Reduction of turn around period as some inspection can be done
on stream.
• Increase inspection efficiency and effectiveness
• Reduce risk exposure and increase safety and reliability of the
plant
Reliability Centered Maintenance (RCM)
(Best suited for Rotary, Instrument & light
Electrical items)
Role of RCM
• RCM is a technique for developing a most cost effective PM
program.
• The elimination of counter productive tasks leads to more
effective maintenance.
• RCM creates awareness in Maintenance professionals regarding
six patterns of failures. Maintenance professionals, as such, comes to terms with the
reality of randomness after decades in bathtub.
• An awareness of these facts has led some organisations to
abandon the idea of PM altogether for failures with minor
consequences.
RCM Process Overview
STEP-1
RCM process determines the functions and associated performance standards of the assets in its present operating context.
• Output, Thru’put, Quality
• Safety & Environmental Integrity, Quality
STEP-2
RCM process identifies the ways in which the asset can fail to live up to these expectations (failed states).
.
RCM Process Overview
STEP-3
Then follows FMECA (failure modes and effects criticality analysis), to identify all the events which are reasonably likely to cause each failed state.
STEP-4
RCM process seeks to identify a suitable failure management policy for dealing with each failure mode in the light of its consequences and technical characteristics.
.
RCM Process Overview
STEP-5
The RCM process provides powerful rules based on RCM decision logic diagram and decides whether any failure management policy is technically appropriate and worth doing.
Failure management policy options include:
– predictive maintenance – preventive maintenance – detective maintenance – change the design or configuration of the system – change the way the system is operated – run-to-failure.
RCM Process Overview
Failure Management – Basics
• The consequences of failures are far more important than their technical characteristics.
• Proactive maintenance is not to avoid failure per se, but to avoid or at least to reduce the consequence of failure.
• It also encourages us to think more broadly about different ways to manage failure, rather than to concentrate only on failure prevention.
BENEFITS OF RCM
• Greater safety and environmental integrity
• Improved operating performance(output, product quality and customer service)
• Greater maintenance cost effectiveness
• Longer useful life of expensive items
• A comprehensive data base
• Better team work
.