66” water line hot tapped in 36 hours

Summary of the Project

Wellube successfully performed line stopping and hot tapping on a live 66″ cooling water line in a chemical plant in Saudi Arabia. The service was performed with no interruption to operations hence no loss of revenue to the client. It was one of the toughest engineering challenges we worked on in 2017 not just due to the size but also the configuration of the piping system and condition of the pipeline.

Client Requirement

The client approached us with a failed valve on the main plant cooling water manifold, which needed isolating and changing to allow a part plant shutdown. The key challenges we faced were :

• While we have previously carried out line stopping up to 40″ above 70 bar, the issues with this much larger line, connected to a common manifold were that the spiral wound pipe was irregular in shape and ovality excess of 1-1/4″ which created problems with installing a contemporary round line plugging head.
• To counteract the issue, the plugging head was modified with adjustable backing plates to support the seal in areas where there was excessive ovality.
• The line plugging equipment was an excess of 15m in length with a combined weight of 20tons; the weight had to be safely balanced by engineering special supports to reduce the load on the parent pipe.
• While the system was running at 8 bar, we had to design and manufacture the head to allow a safety margin of 1.5 bar.

Unique Solution we delivered

We designed a 66” line plugging equipment suitable for 12 bar pressure applications, which was proven through full FAT mock-up trials prior to deployment on-site and was inserted through a 48” hot tapping point. To counteract the ovality issue, the plugging head was modified with adjustable backing plates to support the seal in areas where there was excessive ovality.

Benefits delivered

• The whole line plugging operation and valve removal/insertion was completed within a 36-hour window, with 100% leak-free isolation being achieved
• On completion, the client was able to replace the 66” in-line valve without a total site shut down to production.
• No loss of revenue to the client