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RE: Scaling in cooling towers



Patty,

I would assume that the bromine compound is for control of biological growth
rather than cleaning (i.e., scale removal).  Scale removal can be a
difficult job and I would make sure the plant is doing what it can to
prevent scale formation rather than search out a bigger better scale
remover.  A few quick items I would check into:

Source of the cooling water, is it high in iron ?  The scale may occur when
the water is aerated.

Leaks of product and process fluids into the cooling circuit.  Beverages
would be a great food source for bugs in the tower.  Remove the food and the
bugs stop growing.

Barometric condensers.  They allow direct contact of the cooling water with
process vapors, thus adding a potential food source to the water.

Proper pH control of the cooling water circuit.

To remove scale from a system, strong acids may be used.  This can create a
hazardous mess and the circuit needs to be neutralized before being placed
back on-line.  Equipment damage can result if you use the wrong acid.

I once saw someone use HCl to remove water scale from an air stripper.  HCl
reacts with the carbonates to form CO2 and chlorides.  Nothing too bad
there.    NaOH may then be used to neutralize the HCl remaining in the
system.  Only problem is that HCl is volatile and NaOH is not.  The HCl
vapors carried over into an offgas heater and corroded the unit.  A
different acid should have been used to protect the downstream equipment.

I don't have any names but there are companies that specialize in boiler and
tower cleaning.  They perform the service and even have on-site treatment
system for handling wastes.  I would also contact Nalco, they specialize in
the chemical control of cooling water systems.  The Thomas Register can
provide contact info.

Hope this help,

Mike.callahan@jacobs.com 

> ----------
> From: 	EADC Lab[SMTP:EADC@isenov.ise.ufl.edu]
> Sent: 	Friday, March 06, 1998 9:28AM
> To: 	p2tech@great-lakes.net
> Subject: 	Scaling in cooling towers
> 
> Hello,
> 
> I am dealing with a bottling co. that has a cooling tower.  The 
> cooling tower has problems with scaling.  I was curious to know what 
> type of descaling chemicals are available.  Currently, the facility 
> uses a bromide chemical to clean any impurities.  
> 
> This company also blow molds their own bottles.  The blow molded 
> bottles are made of Polyethylene Terephalate.  There are many 
> defective bottles in this process, how can this be prevented.  Any 
> ideas would help.  Please contact me by E-mail at 
> Padma@grove.ufl.edu.  Thank you.
> 
> Patty Muthuswamy
> Team Leader
> Industrial Assessment Center
> University of Florida
> Email: Padma@grove.ufl.edu
> Phone: (352)392-7690
> 
>