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SS for this water?

SS for this water?

SS for this water?

(OP)
Hello.
We are currently designing some piping to convey sea water for RO plant.
Please help to find an optimal kind of SS for such analysis of water:

Na     6200 mg/l
Mg     45
Ca     40
HCO3   100
Cl     7300
SO4    1200

(temp=2-20 C)
We're examine such variant:SS316L.
Is there any reason to use SS316ti or duplex?
Sea water near Odessa (Ukraine)

RE: SS for this water?

High chlorides suggest thtat higher grade duplex would be best. Or consider composites, GRP or similar.

Mark Hutton


 

RE: SS for this water?

Agreed, I would use a duplex stainless steel for this application. It is stronger and has increased corrosion resistance over conventional 316L.

RE: SS for this water?

(OP)
maybe 317L with PREn = 29 ?

RE: SS for this water?

If you have to go metallic it will be 25Cr super duplex with a compositional restriction to hit a pitting resistance equivalent number of 40 minimum.

Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
 

RE: SS for this water?

For long term service you should look at concrete and GRP.  If you want to use metal you are talking about a 25%Cr super duplex or a 6%Mo super austenitic.  A 2205 or even hopped up 317LM will not handle this water for the long term.  You will end up with under deposit crevice corrosion.

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Plymouth Tube

RE: SS for this water?

YAHA,

The temperatures of the seawater are good for HDPE plastic pipe and the HDPE is also a good choice for underground installations.  Look for KWH, Weholite, Polypipe, Rinker, Performance Pipe, Kanalrohrsysteme, and others for polyethylene piping systems.  Diameter to 750 mm and larger are available.  You might consider some of the plastic / lined valves for these temperatures.  Many DI water systems use polypropylene lined steel piping around the resin beds.  I would avoid the PVC plastic piping due to brittle material properties at the lower temperatures.  If the pressures and temperatures are increased, then the need for duplex stainlesses will need to be evaluated.  

   

RE: SS for this water?

YAHA/ApC2Kp,
The HDPE pipe is a good option, for above ground high pressure application also consider HDPE lined Steel too. PIHA is a good manufacturer who has got around the problems of the HDPE liner "walking" out of the steel liner due to thermal expansion.

Mark Hutton


 

RE: SS for this water?

302 stainless steel could be a possibility

RE: SS for this water?

What about the use of Duplex 2101 for plate and 2205 for pipe.  The 2101 cost is somewhat competitive to 304L.

RE: SS for this water?

2101 will not handle this water, it is too lean.
2205 would work for a while.

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Plymouth Tube

RE: SS for this water?

I suggest you need UNS 32750 or UNS 32760 material for this RO application if a non metallic does not suit your application. 254SMO is also another choice.

Prices for super duplex materials are very competitive if you buy in quantity. there is spare capacity at the mills.

Be advised that it is not only the materials but the welding and post treatment that will be needed to mee these corrosive conditions. (refer ASTM A380)

RE: SS for this water?

(OP)
Thanks to all!

Now We're examine such variant 1.4410 or 1.4462.
Concentration of hypoclorit (NaOCl) 1 ppm in our water.
What abou this choice?

RE: SS for this water?

The 316 will not work, and the 2205 will pit if there is any dirt or fouling.
Admit defeat and look at 25Cr super-duplex grades.

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Plymouth Tube

RE: SS for this water?

Stanier
Interesting report, though quite high level. I am currently involved in the Adelaide Desalinatin Plant, so it is particularly relevant.

Mark Hutton


 

RE: SS for this water?

HEC

I was responsible for the Durability Plan for Adelaide Desal. Back in Sydney now. Must talk sometime.

What organisation are you with?

RE: SS for this water?

Own company/contract to APP currently hutton4eng@picknowl.com.au I know posting contact detail on forum is verboten but hey, life is short!

Mark Hutton


 

RE: SS for this water?

Google Sandvik's hyper duplex  

RE: SS for this water?

A hyper duplex would be overkill for this application.  With only half the Cl of seawater any of the standard seawater alloys should be fine.
The most economical alternative would be a 25% Cr duplex.  With their high strength you can use less metal.  And you will get good service life.

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Plymouth Tube

RE: SS for this water?

(OP)
Thanks all!
What about chinese duplex and superduplex stainless steel (quality/price)?
What chinese brand can you advise?
Has cooperation with chinese producers any specifical moments?  

RE: SS for this water?

If you are serious about quality then perhaps you need a supplier review process that goes a little beyond informal recommendations on eng-tips ...

"It is unwise to pay too much. But it is worse to pay too little. When you pay too much, you lose a little money; that is all. When you pay too little, you sometimes lose everything because the product you bought is incapable of doing what it was bought to do."

"The common law of business prohibits paying a little and getting a lot. It can't be done. If you deal with the lowest bidder, it is well to add something for the risk you run. And if you do that, you would have enough to pay for something better."

"There is hardly anything in this world that someone can't make a little worse and sell a little cheaper-and people who consider price alone are this man's lawful prey."

By John Ruskin 1819-1900
 

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