Shell & Tube Heat Exchanger Test

[Mostafa Fouad]

Hi every Body ;
there is a heat exchanger shell side pressure 17.5 bar and tube side pressure 10.5 bar always when i test its sell side it is ok ; but every time i test the tube side some of tubes leak at pressure 7 bar, i plugged them and do the test again another tubes leak and so on.
i don't know why when i test shell with high pressure there is no tubes leak otherwise it leaks at lower pressure when i test the tube side.

 

[MikeHalloran]

I'm used to heat exchangers with a pressure limit of 2 bars, so there must be very sturdy tubes in yours.

If the tubes are engineered to operate at 17.5 bar while pressurized internally with 10.5 bar, and you are testing the shell side at 17.5 bar while the tubes are not pressurized, you may be cracking or buckling the tubes.



Mike Halloran
Pembroke Pines, FL, USA

 

[Mostafa Fouad]

thanks Mike Halloran
but it is written at the heat exchanger nameplate shell hydrostatic test pressure 17.5 bar and tube hydrostatic test pressure 10.5 bar

 

[blacksmith37]

Depending on geometry ( especially any small dents , etc) and material strength, collapse of the tubes when the shell is pressured and the tubes are not , seems to be a possibility.

 

[SJmetallurgist]

You said that tubes are leaking at 7 bar pressure only...
Could you clarify few points pls:
1. what is the material of tube and tubesheet.
2. Are tube to tubesheet joints type strength expansion (full expansion + no welding)? If expanded, what is the % expansion given to tubes.
3. Is the tube to tubesheet joint strength expansion + seal welding?
4. is the tube to tubesheet joint strength welded plus light expansion?
4a. what is the joint type as per UW20? Ensure that you are providing full welding as shown in figures of UW20 of ASME Sec VIII Div 1.

Once you provide above info., more insight can be gained.

 

[mk3223]

I wondered how you to identify which the leaked tubes were when the hydrotest performed in the tube side?
I thought the leaked tubes were identified when performed test in the shell.

 

[MikeHalloran]

Mostafa, I can't eliminate the possibility that you are using an incorrect test procedure, and damaging the heat exchanger every time you test it.

How about using a test that reflects the _operating_ conditions only?

Or getting a copy of the HX manufacturer's detailed test procedure, and following that?



Mike Halloran
Pembroke Pines, FL, USA