Chemical Cleaning of Naval Brass

[Guibar]

Hi everyone.

I received a proposal for chemical cleaning of a heat exchanger where their tubes are made of naval brass:
Copper ....... 59.5 to 63.5%
Tin .......... 0.5 to 1.5%
Zinc ......... remainder

They specify Sulfamic acid to use as a main removal agent.
I don't know if there is any restriction to use this acid in the material above described.

The kind of incrustation we are trying to remove is deposition of sediments coming from the cooling water.
The exchanger have operated for many years and never had been made a proper cleaning.

If someone can suggest me where I can find answer for this problem I appreciate.

Regards!

 

[StoneCold]

I recently purchased a book about cleaning equipment.
It is called Cleaning of Process Equipment and Piping Joerg Gutzeit.
It was published by the Materials Technology institute of the chemical process Insdustries.
Copyright 1997
It is a good book and covers lots of chemical as well as mechanical cleaning methods.
It's comments on Suflamic acid are the following
Relative Cost: High
Applications: Use with most metals except cast iron, galvanized steel, aluminum alloys or zinc.
Effeciveness
Effective against : Calcium and Magnesium Carbonates, hydroxides, oxides and phosphates in coling water deposits. Iron oxide mill scale and corrosion products
iron phosphates and sulfides.
Ineffective agaist: Calcium and Magnesium Sulfates, Silica and Silicates (requires addition of NH4HF2), Copper Oxide corrosion products

It goes on to give you formulations and corrosion rates. Potential problems, etc.

Regards
StoneCold

 

[rmw]

What is the condition of what ever it is you are trying to clean? Is it scale or just settlement of sediments? Your Hx may need mechanical cleaning or at least mechanical cleaning first.

Sulfamic is the correct choice for this metallurgy, but acid cleaning may not be the right choice for this Hx.

rmw

 

[Guibar]

Thank you both for helping me.

We are going to use only chemical cleaning because we are not able to perform mechanical cleaning.

We basicly want to remove Calcium and Magnesium Carbonates, so we believe we gonna be able to manage it only with chemical cleanig.

I let you know how is gonna end this.

Regards