Customer: SRC(Singapore Refining Company Pte Ltd)
Pipe in question: #7900 Flare Sub Header
Temperature: Ambient to 80 Deg C
Line Content: Sulfur acid concentration 4% – 98% weight
Pipe Size: 18″
Wall Loss: 100% assumed
Sulfuric Acid discharge in the pipe can be in the range of concentration 4 – 98% weight so creating a very corrosive environment. Existing Competitor wrap did not perform up to expectation. In certain areas of the Competitor wrap, there are traces of black stains.The Competitor wrap was installed when there is no leak on the subject pipe so obviously the pipe has since deteriorated to a 100% wall loss scenario in certain parts and the Competitor wrap installed is not compatible to the line content. Competitor was called in to add more wraps and monitored to ensure that the leak stops before a remedial solution is put into place. Customer decides to call in Citadel Technologies for an alternative solution.
To design an engineered Diamond wrap solution and wrap over the existing Competitor wrap onto the Furmanite Clamp as the anchor point. The Diamond wrap kit selected must be able to withstand the pressure, temperature as well as the harsh chemical Sulfuric acid ranging from 4 to 98 percent at ambient up to 80 deg C.
The ASME PCCI2 calculation using parameters from Diamond wrap states that 2 wraps of the BA type fabric is required to restore the pipe back to its original designed condition. The selection of Diamond wrap epoxy is the Acid kit to withstand the harsh Sulfuric acid 4 – 98%.
Work commenced on the 8th November 2010 and completed on the 23rd November 2010. A total of 30 Mandays was used. There was a total 3 days out of this 3 weeks which no work was done due to holiday and bad weather. There was no work done over the weekends.
The existing competitor wrap was sand papered down to give it a good surface for adhesion. The anchor locations – Sides of clamp, Flanges, past the end of the existing wrap where fresh pipe is found, are prepared properly using a sander, MBX tool and wire brushing. Putty is first applied to places where smoothening is required – Sides of clamps, Flange, Y-branches. Wrapping of the straight portion is completed in stages where the pipe support needs to be shifted to the completed Diamond wrap section so that the rest can be completed. Due to the huge transition from the pipe to the clamp, a good amount of putty is prescribed. As the putty is the famed Acid resistant type where it can “foam” up if too much of it is applied at any one point, the work has to be progressive. Once all the putties are applied, we use the sander to smoothen down the putty surface so that when we apply the carbon composite layer, the smooth transition will facilitate the easy laying of the carbon fibers. (*The wrapping was carried out after acid resistant putty cured and confirmation of no leakage status was jointly conducted by the SRC inspectors and InISitu/Citadel (By means of gas detectors and visual inspection) before proceeding to the wrapping works) The work was also carried out with the applicator wearing a 4 in 1 detector as a safeguard.
Application of the putty (Green colour) at the Y-joints in preparation of the wrap. The grey area where it is not shiny with the yellow markings is the existing Competitor wrap. The shiny areas are already wrapped with Diamond wrap.
Application of putty in stages for the flange and the clamp.
Job completed. Wrapping is to 8” onto the clamp on both ends where you can see on the picture on the right. The flange is being wrapped entirely and on the picture on the left, the wrap goes onto a clamp as well.
There are nearly 3,000 trained Clock Spring installers around the world who are qualified to provide repairs with Clock Spring products. Clock Spring regularly offers training classes for installers and can custom design training for individual company needs.