SCOPE OF WORK FOR STUDY & ROOT CAUSE FAILURE INVESTIGATION OF
10-E1405B HEAT EXCHANGER
1. Introduction
Salalah Methanol Company (SMC) owns and operates a 3000 MTPD Methanol plant and supporting Utilities
& Off-sites plant at Salalah, Sultanate of Oman. The principal raw materials for the plant are Natural Gas and
Sea Water. All Utilities (desalinated water, de-mineralized water, steam, cooling water, power, and nitrogen)
are produced within the integrated Utilities & Off-sites plant. Natural Gas is used as feedstock and fuel. Sea
Water is used for producing desalinated water and as cooling media for process needs.
The Methanol Plant was designed by Jacobs Consultancy based on Johnson Matthey’s low pressure
methanol synthesis technology to produce Methanol from Natural Gas feedstock. Water / steam, another
important feedstock for this plant, is obtained by desalination of Sea Water. The plant was commissioned
and started operations since April 2010.
After start-up of the plant, one of the shell and tube exchanger in Methanol Synthesis section encountered
tube leaks which has resulted in contamination of shell side process water and further affected the
downstream process and operation of the units.
2. Purpose
The purpose of this document is to select and appoint a Specialist Consultant to study the design and
construction details of the failed shell and tube exchanger, carry out root cause failure analysis of the tube
specimens in addition to conducting thermal & structural analysis, computerized flow modeling
(Computational Fluid Dynamics) of the exchanger.
3. Background of Heat Exchanger tubes failure
3.1 Tube leaks were observed from one of the shell and tube exchanger Tag # 10-E1405B in Methanol facilities
of Salalah Methanol Company in the Year 2010 after plant start-up and within few weeks of operation.
Exchanger was opened for inspection and necessary repairs during an outage in the Year 2011.
Upon internal inspection of the exchanger, few tube leaks were observed within the tube sheet expansion
area on the gas inlet side of the exchanger. Leaky tubes were identified, plugged and exchanger was taken
back to operation. No leaks seen in the bottom exchanger E1405A
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During Turn-Around 2014, both the stacked exchanger’s 10-E1405A and B were replaced with new
exchangers with slight modified design without change in Metallurgy. Old exchanger leaky tube sections
were removed for root cause failure analysis.
The leaky exchanger 10-E1405B is a stacked one, located above 10-E1405A. Construction, design and
operating details of the exchanger are given below for reference.
Service Parameters
Shell Side
Tube Side
Fluid
Design Pressure, barg (Internal)
Design Temperature 0 C
Operating Pressure, barg
Design Temperature 0 C (In/Out)
Saturator Water
41
275
27
130.3/219.9
Syn gas from converter
90
310
80
255/135.3
Design & Construction data
Code
Shell Material
Tube sheet Material & Thk
Tube material & Total No
Tube dimensions
Type of Exchanger
Number of Pass
Tube to Tube sheet
ASME Sec VIII Div 1’ 04 Ed, 06 AD + API 660
SA240-304 L
SA336-F304L &
SA213-TP304L & 3940 Nos.
O.D 19.05mm X 1.65mm thick X L 12200
H-BEM, TEMA 8th ED, Class R
One (each side)
Strength welded with light expansion
Design data, drawings, process description and chemical composition of the process will be provided upon
request to the bidder.
3.2 The new stacked exchangers replaced in place of leaky exchangers in TA-2014 were also reported to have
tube leaks during operation after plant start-up in May 2014. This is inferred from the performance
parameters and operating conditions of the downstream units. No physical confirmation of the new
exchanger tube leaks was done till date.
The design changes of the new exchanger with drawings will be provided to the bidder upon request.
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4. Scope of Work
Successful bidder (Consultant) shall collect necessary information from SMC to perform the below activities.
Phase 1
4.1
Transient thermal analysis: Conduct FEA modeling to assess thermal transient event impact on tube
and tube sheet differential thermal expansion and corresponding developing stresses on tube.
4.2
Carryout failure analysis of the leaky tube specimens, to identify the reasons for failure.
Phase 2
4.3
Review the design and construction data of the failed exchanger.
4.4
Structural static analysis: Perform Thermal and Structural analysis of the exchanger by FEA modeling,
focusing at the tube to tube sheet joint.
Phase 3
4.5
Perform Computational Fluid Dynamics simulation of the failed exchanger.
4.6
Review of new exchanger design data and provide suitability after necessary engineering studies
(Additional, reference to point 3.2 of this document )
Upon conducting the above studies and investigation, consultant shall provide SMC the root cause of tube
failures, and suitable recommendations to consider in the design of new exchangers to prevent recurrence of
such failures.
Successful bidder may visit SMC to understand the site, exchanger construction and installation conditions prior
to study and submitting the technical report. Prior communication to SMC shall be made for the visit.
5. Deliverables
Reference to scope of work (Item 4 of this document) the consultant shall provide a technical report with
the below deliverables, but not limited to
5.1 Report on Root cause failure investigation of tube specimens, detailing the reasons failure with possible
solutions to prevent recurrence.
5.2 Thermal and structural analysis report
5.3 CFD report
5.4 A Consolidated report with conclusions and recommendations upon engineering study of the exchanger
after review of design, construction data and root cause failure analysis.
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5.5 Design review report of the new exchanger.
6. Requirements of the Consultant
To participate and carryout the study and analysis of the exchanger failure as per SMC scope of work, the
bidder shall have the below requirements as Mandatory:
6.1 Proven experience on similar root cause failure investigation of heat exchangers tubes of petrochemical
or Oil & gas industries.
6.2 Proven experience on conducting Thermal and Structural analysis of heat exchangers.
6.3 Experience on carrying out and conducting computerized flow modeling / Finite Element Analysis of
heat exchangers in petrochemical or Oil & gas industries.
6.4 CV of the experienced engineer carrying out the study and providing report.
Supporting documents of above experience shall be provided by the bidder for Evaluation along with bid
document.
7. SMC Scope
7.1 SMC shall provide data of design, construction and operation of the exchanger to the successful bidder.
7.2 Access to plant and HSE Induction will be provided by SMC during bidder visit.
8. Pricing
The specified project proposal shall be priced as lump-sum payment covering all the items as per SMC Scope of
work (Item # 4.0 of this document). Price quote for each item in scope (4.1 to 4.6) shall be submitted separately
in the proposal. SMC has right to consider all the items or exclude any item during award of the contract.
SMC is of the interest that all items in Scope of work shall be dealt by single bidder though bidder can subcontract item # 4.2 (Failure Investigation of tube samples)
9. Timeline
6 Weeks from the date of award of the contract for complete study and submission of technical report.
10. Exceptions and deviations
Bidder shall define all exceptions, Deviations and Additions with respect to the bid submission, if applicable.
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