How to avoid pit falls in design basis rev 3

How to Avoid Pit falls in
Design Basis ?
Krishna Rajasekhar POLAPRAGADA
M. Tech, D.I.M,
Principal Process Engineer
SLFE- Kingdom of Saudi Arabia
Krishna- Principal process Engineer SLFE- Al-Khobar- K.S.A

What types of Risks exist in projects ?
What we need to
Focus on ?
Cost ? Schedule ?
Safety ?
OR
Missing Design intent ?

Krishna- Principal process Engineer SLFE-
Al-Khobar- K.S.A

Gulf of Mexico Oil well in 2010-
one disaster costs USD 50 Billion to BP.

Why focus on Design ?
• Operators may not be trained !
• 100% Safe Systems may not be present !
• Instruments or equipments may fail !
• Natural disasters might occur !
• We may not learn from past failures!
But all of us want DESIGN to work !

Why Designs fail ?
- Inadequate protection –
no. of Cheese layers.
- Lack of data /accurate data
- Cost/Schedule constraints
- Lack of design expertise/training
- Under-developed or agreed design
standards/protocols.
- Rare risk break-downs.
Eg. Earth Quake or Tsunami.
- Inadequate Design Basis
- Frequent changes to Design Basis
- Ownership of Design Basis
document.
Krishna- Principal process Engineer -SLFE- Al-Khobar- K.S.A

TYPICAL DESIGN BASIS PIT–FALLS
1. Ownership of The Document - Client or Designer ?
2. Project Site location and Design office distance
Eg. Project site is Middle East and Design office in
Houston
3. Under developed Document (incomplete or grey areas )
4. Lack of Data/Clarification and communication.
5. Change in conditions since finalization of original design
intent.
6. Design Basis and Beyond Design Basis
7. Lack of risk based evaluation of Design Basis
.

Elements of Design Basis

Case studies of Design Basis failures
• Case 1 – DATA VALIDATION ERRORS.
Eg. Rain fall – Nil . Humidity – Nil
Summer Max. temp. 440C in Saudi Arabia
• Case 2 – NON REPRENTATIVE SAMPLES -
Eg. Latest Crude assay not available.
• Case 3 – FEED STOCK CHANGE -
Eg. Sulfur units designed for 80:20 AL/AH
vs Sweet Bombay high crude processed .
• Case 4- SPECIFICATION CHANGE :
Eg. Fuel gas H2S content variance with design basis.
• Case 5- BEYOND DESIGN BASIS
Eg. Earth quake zone 4 vs 5

Case 3. Sulfur Recovery Units in Refinery
Year 1980. Project site : 3 Refineries in India
Design Basis : Crude blend of Arabian Light 80% and
Arabian Heavy crude 20 %.
Sulfur content 1.8 %
Actual : Bombay High crude : Sulfur content < 0.3 %.
Result : Plant had to operate at < 7 % Turn down.
condensers plugged.
Furnace did not operate .
Units have to modified/de-rated.
RISK : USD 100 Million.

Case 3 -Low Flow Turn down areas
Low flow effected areas

Case 3 -Process Design issues in SRU
• Normal Design Turn down ratio is 20-30%
• Gases with an H2S content of over 25% are suitable for the
recovery of sulfur in straight-through Claus plants while
alternate configurations such as a split-flow set up or feed
and air preheating can be used to process leaner feeds.
• With change to Sweet Crude , Turn down reduced to 7 %
and caused shutdown due to plugging and leaking of
condenser .
• Initiating a major revamp costing 40% of original capital
costs.

Case 3 – Possible solutions
• Design for a large basket of crudes – cost impact
• Build Modular Equipment – 2 parallel Trains – cost
impact
• Select a process which has low Turn down ratio.
• Operational strategy during change to sweet crude.

Case 4 -Fuel gas for Boiler in Oil and Gas
plant
Year 2000. Project site : Oil& Gas filed in
Middle East
Design Basis : Nil H2 S in Fuel gas
Actual : H2 S in Fuel Gas was 10,000 ppm.
Result : Burner damages.
Boiler tubes corrosion and failure.
Final replacement of Boilers.
potential loss of production.
RISK : USD 100 Million

Case 5 : Beyond Design Basis -
Year 1998. Project site : Jamnagar – India
Design Basis : Earth quake Zone 4
Actual : Earth Quake Zone 5
Risk : or any where above USD 5 Billion
Actual Cost saved was USD 5 Billion by building
Refinery beyond Design Basis .
Note : Earth Quake occurred at Richter scale 8.

Richter scale
The Richter magnitude scale (also Richter scale) assigns a
magnitude number to quantify the energy released by
an earthquake. The Richter scale, developed in the 1930s, is
a base-10 logarithmic scale, which defines magnitude as the
logarithm of the ratio of the amplitude of the seismic
waves to an arbitrary, minor amplitude.
As measured with a seismometer, an earthquake that
registers 5.0 on the Richter scale has a shaking amplitude 10
times that of an earthquake that registered 4.0, and thus
corresponds to a release of energy 31.6 times that released
by the lesser earthquake.[

Risk evaluation of Earth Quake

Earth Quake Zones of India

Following the March 2011 Fukushima Daiichi nuclear plant accident in
Japan, DOE embarked upon several initiatives to investigate the safety
posture of its nuclear facilities relative to beyond design basis events
(BDBEs).
These initiatives included issuing
• Safety Bulletin 2011-01, Events Beyond Design Safety Basis Analysis
• Review of Requirements and Capabilities for Analyzing and
Responding to BDBEs,
• , OE-1: 2013-01, Improving Department of Energy Capabilities for
Mitigating Beyond Design Basis Events.
• Protocol for Enhanced Evaluations of Beyond Design Basis Events
Supporting Implementation of Operating Experience
Final case : Beyond Design Basis
Fukushima Daiichi Nuclear plant accident in Japan
BEYOND DESIGN BASIS EVENTS
Krishna- Principal process Engineer SLFE-
Al-Khobar- K.S.A

Solutions to avoid Design Basis Pit-falls
1.Design Basis Review : Review by owner and Designer
during 0 % , 30% and 60% completion of project , based on
Risk factors.
2. Beyond Design Basis or Design Basis Accident :
Think beyond Design Basis and be prepared
3. Hire professional Engineering Company :
Appoint GES contractor for Design Basis documentation.
4. Data collection: Monte Carlo method or frequent samples

Design for Design Basis Threat
Courtesy “ DOE

HAZOP
HAZID
PHR
PSM
Next to mitigate risk?
Right Design basis !

Key to Right Design Basis !
• Regular Review by owner
and Designer
• Confirmation by accurate
Data.
• Communication and
Documenting changes.
Thanks !

Some References
1.A Design Basis accident (DBA) or maximum credible accident (MCA) is
a postulated accident that a nuclear facility must be designed and built to
withstand without loss to the systems, structures, and components
necessary to assure public health and safety.
2. Monte Calro analysis Monte Carlo simulation, or probability simulation, is
a technique used to understand the impact of risk and uncertainty in financial,
project management, cost, and other forecasting models.
3. Design Basis : Set of conditions, needs, and requirements taken
into account in designing a facility or product.
4. As per GSA (USA). The Basis Of Design (BOD) describes the technical approach
planned for the project as well as the design parameters to be used. The BOD is
typically developed in technical terms, whereas the owner’s project
requirements are developed by GSA in concert with the customer agency and
are expressed in layman’s terms.

References and Abbreviations
• MOC- Management of Change
• PSM- process safety management
• PHR – Process Hazard review
• PHA- Process Hazard Analysis
• HAZOP- Hazard and operability review
• HAZID – Hazard identification
• DBA – Design Basis Accident
• GSA – Geographical Society of America
• BDBE- Beyond Design Basis Events.
• DOE- Department of Energy (USA)

How to avoid pit falls in design basis rev 3

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