Oil Refinery Major Pipe Repair Programme After Water Cooling System Attacked by Microbially Induced Corrosion
Sylmasta devise a major pipe repair programme for an oil refinery after microbially induced corrosion caused welded joints to leak throughout the facility’s stainless steel water cooling system less than halfway into its expected lifespan.
Case Study Overview
Site Oil refinery
Location Middle East
Pipe Type Stainless Steel Water Cooling System
Pressure Up to 10 bar
Repair Type Live Leak Repair
Products Wrap & Seal Pipe Burst Tape, SylPad Pressure Resistance Multiplier, SylWrap Pipe Repair Bandage
Pipe Defect
The stainless steel water cooling system at the refinery was meant to have a lifespan of 50 years, yet numerous welded joints had started leaking after less than half that because of microbially induced corrosion (MIC).
MIC occurs when microbes fix to a surface and produce a biofilm layer where different bacteria combine to accelerate the corrosive process.
They do this by affecting the electrochemical environment in multiple ways – including changing ion concentrations, pH values, oxidation levels and creating hydrogen sulphide.
Stainless steel normally has enhanced protection against MIC thanks to its passivation layer, which prohibits microbes attaching and makes surfaces less prone to developing biofilms.
Unbeknown to the refinery, welding joints during the installation of the cooling system had weakened the internal passivation layer.
Microbes in the water were subsequently able to settle on the uneven surface at each welded joint and attack the pipe from the inside, eventually weakening it to the point leaks began developing across the refinery.
This represented a major problem at a relatively new and expensively built facility. The system could not be replaced due to cost and disruption.
MIC is almost impossible to eliminate once it has taken hold. As more biofilm layers form, bacteria and microbes are given greater protection from treatment methods such as biocides, chemicals and temperature fluctuations.
Every welded pipe joint was now a potential point of failure. Shutting down the system for repair whenever a leak appeared resulted in five days lost production and vast cost for diversions of water.
The oil refinery contacted Sylmasta looking for a live leak pipe repair method which could quickly seal breaches in the water cooling system as and when they happened.
SylWrap Solution
Over 1,700 Wrap & Seal Pipe Burst Tape and 500 SylWrap Pipe Repair Bandages were sent to the refinery. Sylmasta also flew to the Middle East and spent a week on site to train, test and certify installers and supervisors on making live leak repairs.
Leaking welded joints are now sealed using Wrap & Seal and SylPad Pressure Resistance Multiplier. Wrap & Seal stretches by three times its length and amalgamates to form a solid rubber band, containing pipe content.
Multiple Wrap & Seal applied on top of each other amalgamate in the same way, building pressure resistance up to 30 bar. This was more than suitable for the 10 bar maximum the water cooling system operated at.
SylPad is used on pipes 150mm diameter and above. It is placed directly over the hole during the application of Wrap & Seal, better concentrating pressure resistance by directing more of the tape’s elastic force downwards and onto the leak.
Depending on pipe size, the nature of the leak and the quality of the repair, SylPad can increase the pressure resistance of Wrap & Seal by up to three times – meaning less tapes are required and making repair time faster.
After sealing, each welded joint is reinforced with SylWrap Bandage. Overwrapping with SylWrap provides a rock-hard, impact resistant sleeve which protects and strengthens the initial repair.
Outcome
Whilst on-site, Sylmasta were able to see first-hand the problems caused to the water cooling system by MIC and the manner in which welded joints were suddenly failing.
This has proven invaluable to improving Sylmasta’s understanding of MIC, a type of corrosion relatively little is known about compared to other forms.
The refinery were particular impressed with the ability of Wrap & Seal and SylWrap to repair difficult-to-access sections of pipework. Large parts of the water cooling system ran overhead and through constrained spaces, making flexible application a necessity.
Follow Up
Since Sylmasta visited, numerous leaks have been repaired in the water cooling system. Further products have been sent to the Middles East to enable the refinery to maintain what is now a major pipe repair programme.
With eliminating MIC impossible, instant live leak repair has proven the best solution for the refinery.
Products Used
Wrap & Seal Pipe Burst Tape
Self-fusing repair tape which forms a solid rubber band for sealing high pressure live leaks
SylPad Resistance Multiplier
Increases pressure resistance of Wrap & Seal on pipes 150mm diameter and above
SylWrap Pipe Repair Bandage
Water-activated wrap sets rock hard to provide a protective shell around leak repairs
Pipe Repair Contractor Case
Easy-to-store Case containing enough Wrap & Seal and SylWrap for multiple repairs
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