Estimating the wall thickness loss of the pipeline
Estimating the wall thickness loss of the pipeline
(OP)
I have a pigging sample. It has 5000 ppm wt Iron content. I am not sure what kind of iron (ferric or ferrous). I know that the total sample obtained is 100 lbs sludge. Let’s say I know the approximate length of the pipeline is 20 miles. Is there any way we can find out the approximate wall thickness loss of the pipeline. Assume that the iron content is responsible for the corrosion taking place inside the pipeline. Let’s say pipeline diameter is 20 inch and wall thickness is 0.531 in. You can assume any constants like density.
Thank you very much for your response in advance.
Thank you very much for your response in advance.





RE: Estimating the wall thickness loss of the pipeline
Steve Jones
Materials & Corrosion Engineer
http://www.pdo.co.om/pdo/
RE: Estimating the wall thickness loss of the pipeline
After the big assumptions, the math is almost trivial:
5000 ppm Fe x 100 pounds = 0.5 pounds Fe,
÷ by 20 miles = 0.025#/mile
0.025#/(0.284#/cu in) = 0.088 cu in Fe/mile
Take ID of pipe as 20" for simplicity, so inside SA = 3,981,000 sq in/mile,
The thickness of Fe removed is
0.088 cu in/3,981,000 sq in = 2.2 x 10-8 inch
= 5.6 x 10-10 meters.
As diameter of Fe atom is 2.48 x 10-10 meters,
it seems that the pigging recovered about 2 monolayers of Fe atoms.
There's more oxidized Fe left on the inner surface of the pipe.
RE: Estimating the wall thickness loss of the pipeline
RE: Estimating the wall thickness loss of the pipeline
Another possibility, maybe less accurate than intelligent pigging, is to use Long Range Guided Waves ultrasonics.
I suppose that through iron analysis extrapolations it will be very difficult for you to estimate corrosion loss.
RE: Estimating the wall thickness loss of the pipeline
RE: Estimating the wall thickness loss of the pipeline
RE: Estimating the wall thickness loss of the pipeline
RE: Estimating the wall thickness loss of the pipeline
RE: Estimating the wall thickness loss of the pipeline
I do not work for BP. I work for GALP