Sea Water Service Pipeline, 316L? 2

[mufasa1]

I am a mechanical engineer at a large petrocehemical complex in Turkey. We are located on the seaside and we have decided to feed our fire water pipeline with sea water during an emergency such as lack of fresh water or very low fresh water pressure. In the project the suction line from sea to the main collector (serving three centrifugal pumps) is about 50m long. What kind of material is appropriate for the suction line? It will be full of sea water at all times. Is 316L OK? We do not want to have corrosion problem in the near future.

 

[DLANDISSR]

Mufasa:
Consider polypropalene. Sea life does not grow on poly. This would solve the clam problem. Also it high density poly is strong and would not be easily damaged.

Cement pipe using type V cement is very good for sea water but it is good at growing sea life such as clams, etc. If this is use it could be treated with chlorine. A chlorine solution can be derived from sea water with electrolysis. After about 8 hours it reverts back to sea water with no long term effects. Injection of this chlorine solution in the intake would keep sea life out.

Hope some of these suggestions help!

 

[DarthDick]

DLANDISSR, I think you mean "polypropylene" pipe.

 

[Eddy1953]

AT OUR FACILITY IN THE COAST OF CHILE, WE USE SEA WATER FOR THE FIRE AND COOLING SYTEM, FOR THAT PURPOSE WE USE A 16" DIAMETER FRP PIPE, WITH A LENGTH OF 3.5 KMS AND A SURGE SUPRESSER TANK AT BOTH ENDS, THIS IS TO PREVENT A SHOCK WAVE THAT CAN DESTROY THE FRP PIPE.

 

[gramya]

Interesting. The replies of the experts indicate that for sea water carbon steel or lined carbon steel, stainless steel, FRP, PP, superaustenitic stainless steels, cupronickels etc are all used at one or the other place. Who says that SS 316 or 316L is not used in sea water service. All RO Plants will give the testimony of such commercial usage. Problems may come if the water is hot , temp more than 60-70 deg C, then SCC , cracking, heavy pittins start.
I have a write up which i preapared for a seawater using chemical manufacturing company indicating the host of materials suitable for the service ant their priorities in selection due to varied reasons. i may share it if one wishes. No hold from my side. This can be emailed as MS Word doc file.


Narendra K. Roy
Gramya Research Analysis Institute,
PO box 4016, Vadodara 390015, India
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http://www.gramya.com

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