Leak Detection in Dual Walled Pipe 1

[UofAGrad]

Hey Guys,

I have a project we are working on that involves pumping Sulfuric Acid ~1,800 ft to a new tank. This will be a permanent install, the line will be 316L SS with sleeved inside a larger HDPE Pipe. We are in a preliminary engineering phase right now, we expect the SS pipe to be ~8" diameter and the HDPE pipe ~20" diameter.

We recognize this will be a maintenance nightmare to repair the leaks, we are having a hard time identifying how our leak detection system will operate. The ideas we have all seem pretty primitive, there has to be better options out there. We will need to be able to identify the approximate location of the leak, shut off the pumps and make the repair. I'm out of my element with this one but it's hard for me to imagine there isn't a solution out there. Has anyone designed or installed something similar in their careers?

TIA

 

[RVAmeche]

Some double walled pipe systems have a pressure/vacuum system applied to the interstitial space. This allows you to detect a leak based on a drop in vacuum (requires a vacuum pump) or a change in nitrogen pressure (requires a bottle/checkups).

A simpler and more common method is to slope the piping and install a liquid level switch (frequently capacitance type) at the low point(s). This switch will tell you when liquid has contact, notifying you of a leak.

Other more lowtech methods include a sight glass in the low point drain for visual inspection.

For sulfuric acid, your options are likely more limited.

 

[MJCronin]

Talk with these people .... they have installed more double walled pipe than anyone else.

http://www.permapipe.com/

MJCronin
Sr. Process Engineer

 

[Pritam92]

Dear UofAGrad,

We are using guard pipe concept in nuclear industry.

To ease the leak detection in double walled system, compartment can be made with a nitrogen supply line which supply nitrogen at specified pressure.This allows you to detect a leak based on a drop in pressure. you can also use other inert gas in place of nitrogen.

As Sulfuric Acid is a conductor of electricity,Spark plug type leak detector can also be used inside the compartment. If there is a temperature difference exist between both pipe you can use expansion bellows on guard pipe.


for more information please download the file.

 

[hacksaw]

Pipe racks are usual practice. You are inviting major issues in the long term with your approach.

 

[UofAGrad]

@MJCronin thank you for this link. This system appears to be exactly what we are looking for. I have left a message with one of their sales reps and hope to hear back soon.

 

[hacksaw]

Be careful, cross-coutry gas piping is one thing, sulfuric acid piping...well, be careful