Material Selection for the flow line
Material Selection for the flow line
(OP)
For the well stream composition.We are considering the line pipe material-API 5L Gr X65, as per NACE MR 0175.
One has suggested to select Carbon steel with Corr.Allowance of 1.6mm is this selection Ok with this corr.allow??
Considering Line pipe API 5LGrX65 is it also suitable material and what corr.allowance would be sufficicent if we consider 3 yrs service life of flowline??
Alternatively we would like know what will be the selected material and CA in case the design life of flowline is 20 years.
Attached is the well stream composition data.
kindly reply at earliest with all details/answers and formulas used for corr.allowance and service life.
One has suggested to select Carbon steel with Corr.Allowance of 1.6mm is this selection Ok with this corr.allow??
Considering Line pipe API 5LGrX65 is it also suitable material and what corr.allowance would be sufficicent if we consider 3 yrs service life of flowline??
Alternatively we would like know what will be the selected material and CA in case the design life of flowline is 20 years.
Attached is the well stream composition data.
kindly reply at earliest with all details/answers and formulas used for corr.allowance and service life.





RE: Material Selection for the flow line
David
RE: Material Selection for the flow line
RE: Material Selection for the flow line
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Material Selection for the flow line
Good advice. I would argue that pigging without the chemicals would give exactly the same life expectancy, but chemical salesmen have to make a living too.
I see people going to higher grades to try to make the pipe walls thinner for the same MAWP. If the expected line pressure is much above 15 Bar(g) at X65 the SCC calcs get me too close to a failure point for my comfort with the data (i.e., the failure point lies within the dead band on the data).
The corrosion rate calcs all start with a liquid-full system. In a gas line I've found them to fail to be representative of observed data.
David
RE: Material Selection for the flow line
David is correct pigging is very important if you do nothing else, as you will remove (at least much) of the free water. I dont know his line conditins, I assume a very typical flow line. We have done some studies and are in the process of doing more studies with internal corrosion working groups where we test a control, then with pigging only, then with pigging & chemical, then chemical only, then various solids and combinations as well. We have found that chemicals do have a positive effect if used alone with no pigging, and if used in combination with pigging. It will vary depending on flow conditions though. You also have to have the right chemcial to start off with.
As far as grade of pipe, we certainly have been operating at least grade X52 for years without issues of SSC, hardness is important.
RE: Material Selection for the flow line
Are you going to publish your findings? I've never seen any high-quality data that even indicated (let alone proved) that chemicals by themselves had any impact at all on corrosion rates in a gas line.
David
RE: Material Selection for the flow line
RE: Material Selection for the flow line
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The Canadians probably have the greatest experience with the highest H2S contents.
Would the OP like to give us a location of the intended three year flowline so that I can stay well away!!
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Material Selection for the flow line
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Material Selection for the flow line
FYI - Normankhan we oeprate sour gas lines with as high as 35% H2S with carbon steel, but I am not necessarily giving advice to use it
RE: Material Selection for the flow line
could any one provide me free or trial software download link for electronic corrosion engr) ECE-V4 or 5???
Norman
RE: Material Selection for the flow line
A-53, even furnace weld/bell weld ,whatever) :overwhelming amount has been satisfactory.
RE: Material Selection for the flow line
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Material Selection for the flow line
Me too. I have to have a REALLY good reason to go above Grade B/X42 dual stamped pipe and with piggable lines (that get pigged) the corrosion performance of my designs has been about perfect.
David
RE: Material Selection for the flow line
"Sour" service began in La Laq France, then to East TX, then the rest of TX, LA, etc. Today,even China has had some serious H2S pipline failures.
RE: Material Selection for the flow line
Regards,
SNORGY.
RE: Material Selection for the flow line
David
RE: Material Selection for the flow line
Regards,
SNORGY.
RE: Material Selection for the flow line
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04