Monel and Admirality brass

[roker]

can we use in a heatexchanger tubes made of admirality brass with monel tubesheet? we have two cases: hydrogen in shell side and cooling water in tube side, the second case is hydrocarbons vs cooling water, temp in shell side is max 140 C.

REGARDS

 

[unclesyd]

Under normal conditions you are ok. The metals are close enough togather in the galvanic scale not to cause problems.
That is assuming that you have relatively pure H2 and the Hydrocarbons don't contain S.

What is the quality of the cooling water?

 

[rmw]

We used this combination of materials very successfully in sea water heat exchangers, pumps, and piping, and speaking of sea water, now that is one galvanic soup if there ever was one.

rmw

 

[roker]

dear unclesyd,
the water are treated by cationic and anionic beds.
could you please advise the electro-chemical potential difference between these materials.

regards

 

[unclesyd]

The potential is between .15 V and .20 V. In treated water I doubt you will get this potential. This treated water is a little bothersome, as rmw this material combination works well in an ionic soup.
Make sure you get an branded Admiralty material, like C44300, with less than 15% Zn and at least 1% Sn.
There are materials being pushed as Admiralty that are really just Arsenical brasses with greater than 15% Zn and very little Sn.
This is even more important as you are going to have relative pure water which can cause rapid dezincification in many brasses. Depending on the how pure you water is I would monitor the tubes very closely.

 

[MJCronin]

roker,

Are you intending to seal weld the tube ends or simply expand them ?

I would certainly find a shop that has experience with these two materials.

What materials are you using for the channels (heads) of the heat exchanger ?

MJC

 

[roker]

to MJC,
Thank you,
we are expanding in double groove,
the heat exchanger is a hair-pin (Brownfitube) with CS "channel".
regards