Cross-Country Steam Pipelines - Design Code to Use?
Cross-Country Steam Pipelines - Design Code to Use?
(OP)
I would seek recommendations on which International design code to use for a 20", 6 Km, HPHT (900#, 600 degree F) cross-country steam pipline. My problem is B31.1 and B31.3 do not allow higher grade API 5L line pipe at these temperatures, and A106 Gr. B results in very high wall thicknesses. B31.8 allows use of API 5L higher grade line pipe (X60, X65 etc.) only up to 450 F. Any suggestions?
Also, does anyone know of any insulation that has proven long term performance against moiture degradation which would allow consideration of burial for such pipeline?
Also, does anyone know of any insulation that has proven long term performance against moiture degradation which would allow consideration of burial for such pipeline?





RE: Cross-Country Steam Pipelines - Design Code to Use?
athomas236
RE: Cross-Country Steam Pipelines - Design Code to Use?
"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?
RE: Cross-Country Steam Pipelines - Design Code to Use?
RE: Cross-Country Steam Pipelines - Design Code to Use?
We use B31.1.
I have not seen any codes that allow higher stresses for the X grade pipe at high temperatures. You only get higher design stresses at low temperatures.
Line are not buried as we have to allow for thermal exspansion.
Just completed a 3km 60" line.
RE: Cross-Country Steam Pipelines - Design Code to Use?
Thanks guys, this has been helpfull. The particular application for this steam line(s) are reinjection for enhanced recovery, therefore the reason for the high pressures. One of the other problems being the steam source is located 6 km from the field. I will look into the Canadian code, I did see this referenced in a persons CV for steam lines when I was searching the web last week.
I agree that the thermally induced stresses for a buried restrained mode would dictate an increased wall thickness beyond that required for pressure alone at these operating temperatures, and the thrust load at below ground/above ground transitions would be huge, and the line could emrge from the ground if insufficient cover is not provided (i.e. deeper burial.
However, the above ground construction mode costs are also significant to permit the large discplacements with the necessay anchors between loops, and the loops themselves would be significant....unfortunatley, such are the limited choices for HPHT lines.
I am new to this forum, and I think it is great...thanks again.
RE: Cross-Country Steam Pipelines - Design Code to Use?
RE: Cross-Country Steam Pipelines - Design Code to Use?
Dave C
RE: Cross-Country Steam Pipelines - Design Code to Use?
Another problem you may have is coating the line for corrosion resistance. UG pipelines typically use a FBE corrosion coating with a 1 or 2 layer PE mechanical protective coating on top, but any PE layer will not withstand 600F. FBE is too thin to bury without providing some mechanical protection.
If burying is feasible, it might be good to allow for smart pig inspection (provide launchers and receivers), if not required by the CA code. For that matter, it may also be desireable (or required) for AG.
BigInch
-born in the trenches.
http://virtualpipeline.spaces.msn.com
RE: Cross-Country Steam Pipelines - Design Code to Use?
In my exerience, bury steam lines only if there's no alternative. Much of what people know about above grade steam line installations in buildings, plants, etc simply doesn't translate very well to the underground stuff.