Asset Integrity Management To Enhance Process … Bagchi.pdf · Asset Integrity Management To Enhance Process Safety S.K.Bagchi ... Reformer / Naphtha Hydrotreater Unit. ... Tubes.

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


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.


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.


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.


Process Flow of NHT Unit


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.


Figure- Fabrication layout of the B and E heat Exchangers


Figure -Circumferential Weld Damage in the B Heat Exchanger.


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

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

RISK MATRIX

.

MANAGING ACCEPTABLE RISK

.

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

THE TRANSITION

.

RBI PLANNING PROCESS

.

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.

A

C

D

E

F

B

F Failure is not dependent on age

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).

.


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.

.


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.


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

.

THANKS

.

Asset Integrity Management To Enhance Process … Bagchi.pdf · Asset Integrity Management To Enhance Process Safety S.K.Bagchi ... Reformer / Naphtha Hydrotreater Unit. ... Tubes.

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