Tube material for DM water 1

[mthausif123]

Hi, I want to know whether carbon steel tubes are suitable for an heat exchanger to handle demineralized water flowing in shell side in closed loop, i.e., the demineralized water does not contact with air. Assuming tube side fluid is non-corrosive.

 

[TugboatEng]

Maybe... Tubes need to be thin for the exchanger to be efficient which doesn't support any corrosion allowance. It is possible to use carbon steel tubes (boilers do) but your water treatment needs to be religious.

 

[EdStainless]

How clean is your DM? How clean do you want to keep it?
IF this is very clean water and you want to keep it that way then 316LSS is your first option.

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[mthausif123]

Could you kindly explain the advantages of using SS316L even when the water is already clean?

 

[TugboatEng]

Carbon steel will corrode and eroede and make your DM water not clean.

Is the water demineralized to protect your heat exchanger or is it demineralized because your process needs it to be?

 

[EdStainless]

You will end up with significant amounts of Fe in water if you use CS tubes.
Very clean water is very aggressive since nearly everything will dissolve in it.
You say that it does not contact air, but does this mean that the oxygen content is below the ppb level?

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P.E. Metallurgy, consulting work welcomed

 

[Dhurjati Sen]

The OP says that DM water is being used in the shell side.
What about the DM water lines? What about the shell material of the heat exchanger?
What material are these made of?
The same should be the material for tubes since OP mentioned that tube side fluid is non-corrosive.

DHURJATI SEN
Kolkata, India

 

[EdStainless]

Since flow around the tubes will be much more turbulent it may be worth going to a better material.
The other thing is that with zero corrosion allowance the SS tubes could be very thin.
How long do you want it to last?
How much trouble would the Fe sludge in the DM water be?

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P.E. Metallurgy, consulting work welcomed