Plate Heat Exchanger 1

[gafoorkti]

Gents,

Six months ago we have installed Plate type heat exchanger (Cold Lean Rich Glycol Exchanger) in our plant. Now it is leaking and our client has requested us to carry out root cause analysis and to prpare the report. It is hard to find the exact location of leaking. What will be the cause?
After dismantling heat exchanger what are the specific things to be looked for during initial inspection?

Any comments will be appreciated.

 

[WBH]

Try contacting someone in your area that is experienced with plate and frame heat exchangers. These are prone to leaks for several reasons, some are:

Incorrect gaskets, gaskets not glued,
Some plates are welded with no gaskets, welding issues
Plate thickness, incorrect process for plate/gasket material
Design of nozzle attachments to the head
Incorrect torque of the assembly.

Normally the units are pressure test with water, to determine the source of the leak. If plates, the unit is carefully disassembled paying close attention to the gaskets. If glued make sure properly glued in place with no excess on plates. Pin holes can be located by holding plates up to a significant light source.

I have seen more times that the incorrect gaskets or glue are selected for the process, or not glued when required.

Best resource will be someone locally that has experience. This would also increase your knowledge for the future.

Hope this helps

 

[SNORGY]

I have even seen the manufacturer attach the ASME nameplate directly to the plate pack using rivets.

That one leaked too.

It was a warranty issue.



Regards,

SNORGY.

 

[rmw]

I'd be more suspicious of "snap in" gaskets being improperly installed than I would "glued on" gaskets on a factory new PHE. It's the gaskets that are re-glued after initial opening that in my experience are poorly done that leak and this is because glueing gaskets is a "low totem ple" task and the 'bubba' that gets that job is probably the least qualified person on the team to do finesse work when glueing gaskets ought to be done by the most skilled guy on team.

Make sure your gaskets are compatable with the fluid and that there aren't any pressure or temperature anomolies (water hammer events, pumps going to shut off pressure, etc. that could have shocked the unit.

Run your hand along the edges of the side of the plate pack and see if any of the plates are visibly or 'to the feel' out of line. I have had factory new PHE's leak because even they got a plate slightly out of alignment. And, they should be the ones that should have been able to have done it right.

Your PHE will have a discreet dimension with a fairly tight tolerance to which it should have been compressed upon assembly. Check that (1) the movable plate is at that dimension, and (2) that it is at that dimension on all 4 corners.

WBH's point above about checking the pipe loads is important. If you have pipe loads putting moments or forces onto the frame plate, (or the movable plate if so configured) those can warp the frame plates and loosten gaskets up and make the thing leak.

Find out from someone at the plant (not someone in Management with something to hide) if the PHE has been opened since it was received and installed.

Thousands and thousands of PHE's go into service without leaking so there is a reason out there somewhere. Some, on the other hand do leak. I've dealt with both. There is always an identifiable reason.

rmw