14″ Elbow Diamond Wrap with Strongback

Client: Tengizchevroil

Problem Summary

separator-beru

Anomaly Description:
Operations reported a leak of flexsorb on line 051-CDM31-10-150K01 of column D-503 between nozzles N5 and N10. The external inspection found the leak through a hole with a diameter less than 1mm on the piping straight section 40mm wide within HAZ of the flange connection attachment weld. The leak was repaired temporarily for a short-term period. Ultrsonic thickness test was performed within the leaking area and on the adjacent sections of the piping. The thickness of the damaged straight section was T = 3.6 ÷ 4.6mm, the thickness of the adjacent sections is T = 8.9 ÷ 9.6mm.

Root causes:
At current, the damage mechanism is not identified.

Integrity concerns:
The original thickness of the damaged pipe section does not meet requirements of class 150K01 (T = 7.92mm). It is not possible to calculate the corrosion rate because the thickness initial value is uncertain. Due to this piping being below specification further deterioration of piping could cause worsening leaks and ultimately failure. Operations of the piping with these non-conformities are not allowed.

Technical Details

Line Size:
Design Pressure:
Operating Pressure:
Design Temperature:
Operating Temperature:
Material:
Line Class:
14″
4 BAR
1 BAR
160°C
120°C
SA-516 Gr 70N
150
case-study-images-elboe-diamond-wrap-brocken1
case-study-images-elboe-diamond-wrap-brocken2

The Beruseal Solution

separator-beru

Clamp Design:
By Using a patch and strap the leak through the hole could temporarily be stopped to enable Beruseal to do a carbon fibre Composite repair to rebuild wall thickness and stop the leak (Diamond wrap can not be applied to leaking components unless leaks can be stopped).

Due to the wall loss being concentrated next to the welding, Beruseal designed and manufactured a strongback restraint system that would be able to withstand the total circumferential failure of the welding. The strongback was a multi part system that would restrain the elbow together with the complete assembled flange.

An FEA analysis was performed to calculate stresses in the strongback components in the event of failure of the design pressure.

Seal:
A successful seal of the leak was achieved by the application of the patch to do a diamond wrap composite wrap and with the addition of the restraint system a permanent repair was implemented (20-year life expectancy).

case-study-images-elboe-diamond-wrap-sketch1
case-study-images-elboe-diamond-wrap-sketch2
case-study-images-elboe-diamond-wrap-fixed1
case-study-images-elboe-diamond-wrap-fixed2
case-study-images-elboe-diamond-wrap-fixed3
case-study-images-elboe-diamond-wrap-fixed4

Get in touch with Beruseal

  • On-site repairs for maximum up-time productivity
  • Improved Safety by reducing noise & emmissions
  • Equipment Integrity with international support & custom engineering

Our satisfied clients