4 replies to this topic

[drdave]

In well-maintained cooling tower with conventional water treatment system(ie SHMP+Zn+BIOCIDE+CHLORINE DOSING) , all of a sudden chloride concentration starts showing just double(ie from 300 to 600).
No abnormality in make up raw water chloride content & chlorine dosing stoppage is taken as a precautionary measure.But, chloride content does not fall down to normal.Of course, heavy blow down gives temporary relief .
Cooling tower is in dusty environment of urea to some extent.
What are the reasons for alarming rise of chloride content? ???

[mbeychok]

drdave:

If we assume that the chlorides in the makeup water have not increased, the chlorine dosage has not increased, and the dust in the area has no chlorides, then the remaining possibilities would be:

(1) For some unknown reason, the cooling tower is doing a much better job and hence the evaporation loss has increased. (This is difficult to believe)

(2) The blowdown rate has somehow been decreased. (This could happen)

(3) There is a problem in your laboratory and the chloride concentrations have been incorrectly determined. (This could happen)

These are the governing equations:

Cycles = M/(B+W) = M/(M-E) = [E/(B+W)] + 1

where:
Cycles = chlorides in circulating water/chlorides in makeup water
M = Makeup water
B = Blowdown water
E = Evaporation water vapor
W = Windage loss water

[pkpbip]

What are you cooling with the cooling water?

Could the chloride come from a cooling water tube leak?

[mbeychok]

pkpbip:

You have raised a good point. That is certainly another possibility.

[drdave]

PKPbip & Milton,
We are using cooling water in intercoolers of CO2 compressors,Vapor ammonia condensers & carbamate coolers where chances of chloride content is quite negligible.
As advised by Milton, I have back calculated evaporation loss & tried to work out current blow down rate to compare with previous one on same cooling tower heat load. It indicates point to check further....
Does some chemicals(eg biocides) for cooling tower treatment contain chloride causing such trouble??? !!!