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Low pH at the dm plant

We have a 60m3/hr DM plant.The problem is that after SBA (Anion Ex)the pH never goes up above 5.I had a doubt that there is no sodium sleep from SAC(Cation EX)and after sodium analysis it was found to be true.Now what to do to increase sodium sleep.I cannot reduce acid quantity as the system is built in such a fashion that lower quantity is not allowed.Moreover can there be any other reason for low pH after SBA?

Samrat

Samrat Bhattacharjee
field engineer - Kolkata, India
February 3, 2009

Your demin system is reacting like it has weak base resin instead of strong base resin in the anion vessels, and leaking CO2 and bicarbonate ions.

Is it possible that your anion resin was a Type II resin and that it has been exposed to elevated temperatures? This would degrade a Type II resin and turn it into a weak base anion exchanger.

Lyle Kirman
consultant - Cleveland Heights, Ohio
February 5, 2009

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