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Discussion Forums - The Hendrix Group
HomeHomeDiscussionsDiscussionsGeneral Corrosi...General Corrosi...CP for coolers and condensersCP for coolers and condensers
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8/9/2004 9:00 AM
 
We have carbon steel ( Shell , Tubesheets and Tubes ) coolers / condensers and the water being circulated is coming from cooling tower where chemical treatment is done. The Langleir Index of our cooling water is in the range of -1.5 to -0.8. We are experiencing tube end corrosion of CS tubes and pitting of water box. Will the use of Mg or Zn sacrificial anodes give some good results? Is it benificial to use Sacrificial anodes in the system having the same metallurgy ( Shell , tube sheets and tube - all carbon steel )?
 
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8/10/2004 9:00 AM
 
Neeraj: It is quite common to place sacrificial anodes in the channel of a carbon steele shell and tube heat exchanger to mitigate the corrosion you are referring to. Hope this helps! David Hendrix The Hendrix Group Inc.
 
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8/16/2004 9:00 AM
 
Dear Sir, Is there any statitical data by which we can know that : 1. If we use Mg based sacrificial anodes in Carbon Steel coolers / condensers ( in cooling water service of LI value = -1.5 ), approximately how much % life enhancement can be achieved. (It may be assumed that size , shape and placement of the Sacrificial anodes are adequate. Considering the tube metallurgy as A 179, shell as A 515 or 516 Gr 60 and tube sheet as A 266 Cl 2. Suppose there is no painting used. ) 2. Soppose keeping everything constant, if we use Mg base anodes insted of Zn based anodes, approximately how much additional % life can achieved. Hope I am clear in asking my question. Actually i want to quantify the benifit of using Mg based Sacrificial Anodes. Regards. Neeraj
 
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8/31/2004 9:00 AM
 
Neeraj, although you have not mentioned that which sort of chemicals are being dosed in to the cooling tower,and what is the pH of the recirculating water,but one thing that one can asses from the range of LSI(-1.5 to -0.8), is that its an acidic treatment, i am giving you some recommendations and please let me know that you are already complying with that, if not then please do follow that: 1) doze Zinc based chemical with a despersant, and maintined Zn residaul in the range of 2 to 4 ppm. 2) maintain pH in the range of 7.5 to 8.2. 3) maintain total alkalinity in the range of 50 to 300 ppm. 4) used proper biocide to protect your system against microbiologically ifluenced corrosion. 5) you can use soft water and raw water as well. 6) while dosing acid which i think must be Sulhpuric acid please manitained your gypsum cycles in the limit. if you will provide me with data of your raw water analysis and circualting water then i will be able to calculate that at which cycles your system is running. i hope i have conveyed. thank you, Tariq khan
 
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10/12/2004 9:00 AM
 
we have a system to combat rust by introducing silver ions into the water stream which makes rust and scale come off the walls. This must be filtered out to obain a clean cooling water system.
 
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