6 replies to this topic

[Alzack]

Hi there,

My cooling tower (clean cooling tower) in an edible oil refining factory is getting worse and worse up to the extend that very light blackish/greyish foam appeared on the surface of the water and accumulates to form thick sludges. For the pass 8 months, we have to do more blowdown to dilute the water. We also made a sand filter to further improve the water quality. We check all heat exchangers, most of them plate heat exchangers and only very few spiral coolers. We tested and checked all this heat exchangers to detect any oil leakages that might escape to the cooling water line and creating problem in the cooling tower. However, when we conducted air test/hydro test for the heat exchangers, it's proven that the heat exchangers are ok. I'm already tired of checking all these heat exchangers from time to time without detecting where's the oil leakage source.

What other methods can i try to detect the oil leak that jeopardise my cooling tower?

Thanks

[sar_des]

alzack,

i think you might be facing problem of bio-mass, which accumalate into your sestem.
just try some good biocides dosage to remove this.

rgds,

[Alzack]

Well, i did add up some biocide (Nalco 90001) and also some biodispersant. What i can say now is that the slime is no longer there, indicating that perhaps the home for the bacteria is gone. However, the sludge and accumulation of foam is still there.

Anyway, i'll try and dose in some other biocides.

Thanks

[ashadiazwan]

Hi there,

My cooling tower (clean cooling tower) in an edible oil refining factory is getting worse and worse up to the extend that very light blackish/greyish foam appeared on the surface of the water and accumulates to form thick sludges. For the pass 8 months, we have to do more blowdown to dilute the water. We also made a sand filter to further improve the water quality. We check all heat exchangers, most of them plate heat exchangers and only very few spiral coolers. We tested and checked all this heat exchangers to detect any oil leakages that might escape to the cooling water line and creating problem in the cooling tower. However, when we conducted air test/hydro test for the heat exchangers, it's proven that the heat exchangers are ok. I'm already tired of checking all these heat exchangers from time to time without detecting where's the oil leakage source.

What other methods can i try to detect the oil leak that jeopardise my cooling tower?

Thanks

Actually u can check yr water quality based on langlier and rayzanar index, and reduce number of cooling water cycles. Generally this happen when u maintain the cooling water in high cycle >10cycle.

[Zauberberg]

Hello Alzack,

We were facing exactly the same problem several months ago, and the main causes of sludge accumulation in the CW loop were heavy VDU distillate in-leakage through pump mechanical seal cooling system, followed with HVGO pumparound water cooler (trim-cooler) occasional leakage. The problem in detecting such disturbances, in my opinion, is complicated by the fact that leakage is not happening on a continuous basis - we were taking samples from cooling water headers (inlet and outlet from VDU) every day, and only one of seven (!) analyses showed that leakage is occuring. So, do not take those hydrotest results too "literally" - process equipment often shows unique behaviour at process conditions (i.e. higher temperatures).

Few years ago, one of our refineries was forced to shut down all proces units before the problem was finally identified and solved.

I recommend you to perform leakage tests more frequently. By time (if there is any!) you will reduce the number of suspected locations. Check also your make-up water rate and quality, I think there must be some biocide level (usually chlorine) in CW return header, but I cannot remember the value at the moment.

Please let us know how your situation is developing.
Best wishes

[Radionise]

This thread is interesting. Is there any update on this, Alzack?

[Alzack]

This thread is interesting. Is there any update on this, Alzack?

Thanks all you guys for your response....

Ok, I think my cooling tower is doing fine right now...the foam is no longer there...or it's very minimum which might be the effect of adding chemical only..So, I'm no longer worried with the situation....
What we did was actually dismantling 2 out of 8 heat exchangers that uses the water from the cooling tower. We replace the gasket and we run the plate heat exchanger again...and guess what...my cooling tower gradually becomes ok....

Prior to that....i mean before replacing the plate heat exchanger gasket....i did install and make full use of a sand filter....to help cleaning the water from the cooling tower a little bit. Well, at least it help. And i back wash the sand filter twice daily. And the water is very bad...blackish colour....so, i backwash until it became clear....

Now, i'm just protecting the cooling tower with the chemical program....

another big cooling tower is waiting to be installed with 3D trasar..of nalco....maybe...i think so...somebody else is looking after that one....

thanks for all the help guys....