Temporary Repair using liner/resin wrap?

[YungPlantEng]

We’ve had issues on a vessel chasing the weld with crack propagation originally induced through chloride attack. This vessel is a POS and we’re sourcing a replacement. There is also deep pitting observed on the vessel. All of this is a result of CUI.

Since we don’t appear to have any luck welding on it, would we be able to utilize a resin and carbon fiber wrap either internally or externally on the vessel? This vessel is not run at high pressures currently - maybe 9 psig max although it’s rated to 40 psi. And we can be assured that the polymer/liner/resin used would be acceptable for service due to the manufacturer designing our other lined tanks.

From my understanding NBIC doesn’t cover temporary repairs. Would we just use the relevant ASME code or is a cowboy patch like this just blatantly illegal? We’re working alongside a contractor with R-stamped welders and two different AIs who recommended the idea but don’t seem to have a breadth of experience with this to be honest.

 

Sounds like an enhanced duct tape approach.
Consider boxing in the weak region (aka 'Furmanite'). This is obviously easier around pipes than vessels, but worth considering.
Am I reading between the lines that you are trying to convince your management to shut it down sooner rather than later?

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[r6155]

This PV must be taken out of service immediately.

Regards

 

[YungPlantEng]

It’s not in service until we have an AI review the the repair and a PE sign off on the design calculations for the repair (if a repair is possible)

Does anyone have experience with ASME PCC-2 specifically the section on nonmetallic repairs? Would this even apply to ASME VIII Div 1 vessels?

Will likely just discuss with AI tomorrow on that possibility. The alternative is being down for 6 months so surely there’s some code repair that can be performed on the vessel.

 

[iangineer]

We use composite wraps fairly often as a temporary repair at my plant. For a propagating crack, you need to drill out the ends so that it stops growing. Belzona is one brand of wrap we use and they would know what kind of epoxy is compatible with your process. They can hold a good bit of pressure up to like 400°F. As long as there is not an ACTIVE leak, a wrap can be installed. This would be a temporary repair, though, so it would need to be inspected more frequently than a regular vessel. Depending on the process in the vessel this could be typically from 3-month interval to 1 year, but could be as often as every week or two.

 

[r6155]

In my opinion, cracks in a weld must be repaired only by welding.

Regards.

 

[iangineer]

In my opinion, cracks in a weld must be repaired only by welding.

I agree, or by replacing the vessel, but it takes time to replace a vessel and OP mentioned welding wasn't a viable solution. With a suitable inspection plan and the vessel only operating at 9psig, a wrap would be a good SHORT TERM repair to give time for a replacement vessel to be fabricated. The main issue I see with utilizing a wrap would be it being forgotten once it is applied.

PCC-2 Part 4 is the section for nonmetallic and bonded repairs.

 

[r6155]

@ iangineer
Exactly.
Some temporary repairs are ultimately permanent. Then come the disasters.

Regards

 

[YungPlantEng]

Yes regardless of the fact that we’re going to monitor the repair and the PE promising us that it would be a repair for a 30 year span I’m going to recommend we make the replacement ASAP.

Thanks for the assistance guys!