De-ionized water and corrosion

[garrett]

We use 5 k-ohm and 2 M-ohm deionized water in our cooling systems. Does higher resistivity water cause corrosion of metal components? How is deionized water made?

 

[rustbuster]

My assumption is that the higher resistivity water would afford less corrosion of carbon steel componenets, as the resistance of the electrolyte governs corrosion rates.<br>
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The use of deionized (demineralized) water in cooling water systems is rare in my experience. These treated waters are typically used as Boiler Feed Water.<br>
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Demineralization of water is the removal of inorganic salts by ion exchange. These systems consist of one or more ion exchange resin columns that include a strong acid cation unit and strong base anion unit. The cation resin exchanges hydrogen for the raw water cations. Then the effluent is passed through the strong base anion exchange resin where the resin exchanges hydrogen for mineral ions and acids. <br>
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This results in high purity water, comparable to distilled water but with lower treatment costs.<br>
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Hope that helps...