Heat Exchanger Problem

[demreyes]

We are using heat exchanger to heat our borate/ethylene glycol solution to 180 F and cooling it down at 125 F. After it reached the 180 F we heat it further for an hour. We noticed that after 9 batches, the solution becomes grayish(comtamination most probably from the boiler and cooling sytem). We asked the heat exchanger specialist to come down to check if there is a leak but he can't find any. Can anybody help? I will appreciate any comment/help.
Thank you.

 

[StoneCold]

Maybe the borate is eating up the exchanger? What kind of borate is it? How aggresive is the chemistry? Are there Fluorines involved or Chlorine involved? What is the alloy of the exchanger and piping?

Regard
StoneCold

 

[demreyes]

We are using Disodium Octaborate Tetrahydrate. There is no chlorine or flourine. I believe the contamination is coming from the cooling process, because the cooling water has a lot of grayish particles but why it leaks through the heat exhanger during the cooling process. We sample the solution after heating and it is fine but after cooling it turned grayish. Does the boiler pump which we used also in cooling has some effect to the pressure inside the heat exchanger? Why not in the heating process?

Thanks for your immediate response. I really appreciate your comment.

 

[StoneCold]

Ok my next guess would be that you are eating up the pump, not the exchanger if it is not leaking. Have you though about that possibility?

Regards
StoneCold

 

[IPGBen]

Did you check if there was any kind of analytical way to measure the contamination?
This way you can check your whole process step by step where a possible contamination could occur.

The other question could be: How was the HX checked for leaks (P and T)

Best Regards
Ben