Glycol Leak Causing pH Depression
Glycol Leak Causing pH Depression
(OP)
We had a small glycol leak into the condensate system at the plant. The condensate is controlled around 9.0 pH and is demineralized water. My question is on the chemical reaction between the glycol and the 9.0 pH demineralized water. It caused the conductivity to increase well out of our control range and dropped the pH down to 5. What causes this? what reaction is going on to turn the water acidic?
thanks guys...
thanks guys...





RE: Glycol Leak Causing pH Depression
Gycols degrade to organic acids, aldehydes & ketones in the presence of heat or UV light plus oxygen. Metals such as aluminum and copper catalyze the degradation.
Any pure glycol used as a themal fluid should contain a stabilibilizer (Dow Chemical). Any glycol-water solution should contain a pH buffer and corrosion inhibitors to protect metals in the system.
See 'A Guide to Glycols' from the Dow Chemical Co. http://
and
'Uninhibited Ethylene Glycol' from Thermo Electron Corp. h
Glycol degradation usually results in a noticeable smell & darkening of color, along with the pH drop.
RE: Glycol Leak Causing pH Depression
HOCH2CH2OH + H2O <-----> HOCH2CH2O- + H3O+
There are published equilibrium parameters, called pKa's, that indicate the acidity of various glycols (and alcohols).
Good luck,
Latexman
RE: Glycol Leak Causing pH Depression
As far as I remember, demin water is acidic by nature, as it is purified water, but maybe I am wrong.
RE: Glycol Leak Causing pH Depression
For example, if you have .1 mg/l leakage from a demineralizer, the .1 mg/l would be as sodium hydroxide. Sodium is the first ion to leak from the cation unit. The sodium would then leach the hydroxide ion from the anion unit.
Note that since there is no buffering agent in demin water, it is relatively simple to have an agent cause a change in pH.
RE: Glycol Leak Causing pH Depression
RE: Glycol Leak Causing pH Depression
RE: Glycol Leak Causing pH Depression