SS vs Internal lined Pipes... 1

[admt63]

We are making studies about the material to be used for a boiler feed water line, diameter 8” or 10”, and about 2 kilometers length (also have about 170 elbows).

I would like to receive opinions or information about what is the most economical choice or adventages, about the application of stainless steel pipe and internal lined pipe.

The line will be 8” or 10”, will work about 50 °C and 140 psig.

Thanks in advance for your comments.

Admt63

 

[PAN]

What is the lining material for your case?

Normally lined pipe will be connected by flange connection. Can you accept many flange connections in the line (2 km.)?

 

[TBP]

I don't think you mean "boiler feed water line" for this pipe. At 2 kms, it's far too long, and the pressures and temperatures are too low. I suspect it's a make-up water line.

Having said that, I've personally never liked lined pipe, tanks or vessels for most services. Linings eventually fail, and the problem gets dumped in the laps of the maintenance people. There are some applications where there is just no way around having a lining, but I'd avoid it, if I could.

 

[ApC2Kp]

To admt63,
I would suggest using a high density polyethylene (HDPE) pipe with fusion welded joints in a buried pipe or grade level installation for the 2 km length. There are too many joints for leakage to occur with the typical flanged lined piping system of that length. The 50 deg C temperature is borderline for HDPE, so confirm it with the HDPE supplier. The cost of buried HDPE piping system is low when considering savings of coating & wrapping + cathodic protection of other metallic buried piping systems.
See site of HDPE fusion welding tools for examples,

http://www.mcelroy.com

 

[SJones]

The first thing to do is determine the corrosivity of the fluid to be conveyed to ascertain how much steel you will have to buy to last the lifetime of the facility. It then becomes a question of life cycle costing to ascertain whether any alternative corrosion control measures are more cost effective. ISO 15663 Parts 1, 2, and 3 gives guidance on life cycle costing. If the water is reasonably corrosive, and the costs of multiple replacements/repairs are analysed, it may be that GRP piping in accordance with ISO 14692 offers the lowest life cycle cost option as it will, on the whole, be "fit and forget".

Good luck.

Steve Jones
Petroleum Development Oman LLC
Muscat
Sultanate Of Oman

 

[RNB]

I think that SS may be the most economical choice, I am part of an industry group called SPLASH looking at the economics of SS water distribution piping systems. It compares favorably with DI and coated Steel pipe. You can get more info from Steve Lamb of the Nickel Development Institute at [procrc@earthlink.net] or John Grocki [contact_splash@yahoo.com]