Pipe supports for Natural gas line

[yaar123]

Hello ,

I have a natural gas pipe line in ammonia plant. This pipe line directly resting on support structure. This pipe line does not have any insulation. Whereever it is resting on support structure , there is a local corrioson. Now we are thinking to put supports at each location wherever it is resting on structural beams. Line pressure is 55 bar and temp around 70 deg c
My queres are

1. Is there any other way to avoid corrison issue?
2. If pipe support need to be installed , what precuations should i take

 

[JohnGP]

Pipelines tend to want to move a bit on supports, so any coating on the pipe will likely break down and lead to corrosion at the support points, as you have found. If the pipeline can be raised, one solution is to utilise bolt-on shoes, such as shown in -

http://www.bindergrp.com/wp-content/uploads/2015/01/BG515-Rev-2.pdf

In that way the pipeline can be separated from the supports without having to weld anything onto the pipeline itself. A low friction pad (such as UHMWPE) can be utilised at the support point if there is significant sliding.

 

[NovaStark]

Perhaps wrap the piping in denso tape at the point of contact or add in Teflon pads may help with the corrosion issue.

Apart from that, you may need a stress analysis to ensure that your support placement does not result in high stresses at the points of contact.

 

[BigInch]

generally I prefer a simpler inverted T pipe shoe, or a split sleeve seal welded to pipe. Note that supports for B31.8 pipelines, as opposed to pipes carrying natural gas around in some refinery or gas liquids plant (B31.3), are usually welded to sleeves on carrier pipe and must have full encirclement clamps. Vulcanized rubber pads applied to the full encirclement sleeve where it contacts the carrier pipe will tend to avoid face/face corrosion between clamp and pipe.

OR

Reaction to change doesn't stop it

 

[JohnGP]

Bolt-on type shoes have the advantage of not requiring hot work, which may or not be an issue in that particular plant.

 

[yaar123]

What about I rod and Nu bolt assembly? Any Experience?

 

[LittleInch]

Check out these guys

http://www.appinc.co/products/wear-pads/

the wear pads in particular.

For your situation you may not want to / have the room to lift the pipe up enough to get a clamp support ( probably still the best) or budget to do it.

These types of pads don't need much amount of lifting to get the pie off the support to attach them.

If your pipe (unknown size and wt) is resting on flat beams then introducing a bar type support (like the I Rod) may induce additional stresses / loads

A lot will depend on access, number of supports, ability to lift the pipe off the support, cost and budget.



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[DGrayPPD]

We commonly use the composite wear pads that LittleInch has suggested to aid against the friction between pipe and support.