Two directional Carbon steel pipe - descale - an issue

[jamesbanda]

Dear all,

We have a pipe on site that we would like to use for two directional flow. Is there likely to be a descaling problems. Our operators are conserned by this saying we will have rust in the product.

Material is non-corrosive and non-toxic in the lines. So should we be worried? Do i need to coat the line?

do i need a filter? is there a way i can pre-clean the line?

 

[gr2vessels]

jamesbanda,

First, you haven't advise the service of the pipe (food stuff, nuclear, oil refinery or other service). Second, is it a welded pipe or drawn, second hand from the recyclers with unknown previous service, carbon steel I assume from the mention of rust).

The scale dislodgement you have mentioned is possible in a pipe with single or two way flow only if there is scale present first place in the pipe and the fluid is erosive or of high velocity, capable of impacting the scale for physical removal from the pipe wall.

The scale formation is started by the corrosiveness of the conveyed product. If is not corrosive, there is no rust or new scale. Remember, for the rust formation you need water, oxygen and perhaps temperatures around ambient.

Yes, temporary fine strainer with removable basket could trap the initial scales, from the pipe perhaps poorly selected for the application (there are special requirements for food conveying pipes and other requirements for drain pipes, etc..). However, there is no guarantee that you won't get a late scale or two.

Cleaning of the pipe is always a possibility, but all depends of the pipe material and the pipe manufacturing process, length, feasibility of mechanical or chemical cleaning, etc... A good starting advice;- check the inside of a clean section of your pipe to estimate the surface condition and decide then, you need further advice on this forum or you'll manage yourself.
Cheers,
gr2vessels