MATERIAL SELECTION FOR HIGH SALINE WATER INJECTION PIPELINES 1

[chrysa1975]

We have to suggest Material Selection for Water Injection 6-inch Trunklines & 4-inch Flowlines with Design Pressure = 300 barg and Design Temperature = 90°C. Our concern is the high salinity of the water equal to 220.000mg/lt (two hundred twenty thousand). Any help in the above issue will be appreciated.
PH is 7.4 and TDS are 3400mg/lt. Thanks in advance.

 

[EdStainless]

https://www.nickelinstitute.org/en/...neWaterDesalinationandOilfieldBrinePumps.aspx

Do you mean like this?

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P.E. Metallurgy, Plymouth Tube

 

[chrysa1975]

Thank you very much for your reply. I reviewed the document and please confirm me that in case saline water is considered dearated, carbon steel with corrosion allowance works good. Pipelines length do not allow CRA materials due to the high CAPEX, and temperature of 90°C makes me worry for CPT. Hence I think I will go with CS+6mm CA or CS+internal lining epoxy or glass flake suitable for this high pressure.
Any available guidelines for high chlorides concentration versus carbon steel corrosion resistant, will be appreciated. Thanks in advance

 

[metengr]

Look at FRP piping.

http://www.zcl.com/products/chemical-Products/piping-and-ducting.html

 

[chrysa1975]

FRP would be perfect solution but the design pressure reaches ASME Class2500 for which I think FRP pipes cannot withstand. I appreciate your reply.

 

[metengr]

Lined pipe would be your best option for this application.

 

[chrysa1975]

This was also my feeling too. Thank you both.

 

[SJones]

Glass flake for corrosion protection will be too thick for those small pipe sizes which might create flow issues, notwithstanding trying to apply it in 4 inch pipe. What would be the plan for the field joints?

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[georgeverghese]

We used Zeron 100 ( or was it Ferralium 255, I cannot remember now ) cladded CS for socalled de aerated seawater injection through large bore submarine pipelines at around the same design pressure some 7years ago. Deaeration units for seawater are unreliable and often the bulk of the dearation achieved is by hydrazine injection rather than by physical de aeration.

 

[EdStainless]

You might find that solid SuperDuplex pipe isn't ridiculously expensive, Given the strength you will have relatively thin walls.
Alloys such as S32750 and S32760 would be good options.
I can't see clad being cost competitive for these small lines.

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P.E. Metallurgy, Plymouth Tube

 

[SJones]

The following paper gives some idea of CRA performance in 200,000 ppm chloride at 90 deg C in full blown aerated conditions: NACE Corrosion 2014, Paper 2014-4077.

In a deaerated environment, there would seem to be more than a fighting chance with S32760.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[MortenA]

Just remember (for the high Cr materials) that even small amount of oxygen can be fatal together with high Cl- concentrations. The oxygen con come from many places e.g. chemmicals, lift gas (flare gas recovery, seal gas etc).

 

[EdStainless]

On the other hand a SS would rather work in an oxidizing environment, since it will assist repassivation.

Salinity does not really matter much when you get this high, temp and pH become the real drivers.
Practically speaking once the water is highly conductive more Cl does not accelerate corrosion.

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P.E. Metallurgy, Plymouth Tube

 

[rfartash]

Is there any H₂S in the injection water? The combination of H₂S and chloride (Cl^-) can limit your CRA acceptable options. As mentioned by other the dissolved oxygen level also plays a critical role in the selection.

Roozbeh Fartash
Piping Material & Corrosion Engineer
Bluewater Energy Services

http://www.bluewater,com