Oil & Gas pipeline industry has experience external corrosion and damage impacting its structural integrity for decades. Over 30 years, composite technology has been implemented to strengthen pipelines back to its design condition. The composite application is very common for pipelines of all sizes having operating temperatures from ambient to 60 deg. C.
ONGC – Uran plant is a major facility to process crude oil with associated gas and condensate received from Mumbai High through Subsea pipeline. Regeneration Column was designed for 50 PSI with Design Temperature of 130 Deg. C. and insulated skin. Weather and humidity was accelerating external corrosion around stiffener rings to the point that, it warranted a shutdown to replace either a section or full tower, thereby impacting the production throughput of ONGC-Uran facility.
ONGC hired M/s. EIL as a consulting company to map out extent of corrosion and to identify area needed attention to rehabilitate. Consultant recommended to go for weld build up in identified LML areas (Local Metal Loss) through a planned shutdown of the column.
We were aware about composite technology and further investigation helped to find the right combination of Carbon and High Temperature Epoxy system meeting our requirement through online repair and rehabilitation avoiding shutdown of Regeneration Column.
We selected Carbon with high temperature epoxy based composite system designed for 130 deg. C and installation between 90 to 110 deg. C. Composite application system was designed accordingly and a third party inspection agency was hired to witness prototype tests and composite application techniques. Bonding of Carbon Composite to the Carbon Steel pipe of equivalent grade was successfully tested in the lab.
After infield application, the thickness and hardness of composite system were measured throughout the repaired area during and after the process by TPI. Project was completed by T.D. Williamson in end 2012.