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Thread: Corrosion
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23-01-2009, 05:28 PM #1
Corrosion
I have two brine chillers ,in the off season the chillers are laid up with water containing an oxygen scavenger and a corrosion inhibiter to protect the steel. The chillers are know being readied for use. The chillers are drained and piped to the brine freezer.My question is this to keep corrosion to a minimum, should I leave the chillers empty, should I fill the brine freezers and chillers with water, or should I fill the brine freezers and chillers wth 100% brine. Putting oxygen scavenger and corrosion inhibitors in the freezing system is not an option.
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24-01-2009, 03:27 AM #2
Re: Corrosion
Chief Pack
What kind of brine are you using?
What kind of chiller Shell and tube or PHE?
What kind are the materials of the system?
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24-01-2009, 03:59 AM #3
Re: Corrosion
I had a similar problem many years ago on a brine system for an older ice skating rink & one other for underground soil freezing. The system was only used for several months and then shut off for the remainder of the year. The site manager simply left the system shut off and full of brine. Big mistake!!!
The brine settled out in the under-floor coil and clogged up the pipes in several areas. The brine tank and chiller were leaking from corrosion also. This resulted in a new tank being installed and the chiller being re-tubed.
An old timer told me it's better to have the system not exposed to oxygen (not hard to understand why), and he described something he called liquid locking. This is just what you describe Chief. Except, I don;t think I would use 100% brine. If the chiller can be isolated from the system,, I think I wold drain the brine from the chiller. Pump some water through the chiller to clean it up and remove the brine. Then just fill the chiller with water or if it could freeze, do something like a nitrogen purge to keep it free of oxygen.
Then when you need the chiller reverse the storage process and put it back into service.
It may not be a bad idea to have the tubes eddy current tested once in a while also to verify the tube integrity.If all else fails, ask for help.
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24-01-2009, 08:39 PM #4
Re: Corrosion
I like the idea of the nitrogen, we have done this on compressors we have removed from facility's until we found a new home for them, it helps keep the corrosion away.
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24-01-2009, 09:37 PM #5
Re: Corrosion
gwapa The brine is salt[NaCl] that is dumped into a tank and fresh water is run through the salt producing 100% brine which is pumped into the brine freezer. The chillers are single pass shell and tube with the NH3 gas and liquid separation done in a chamber above the chiller. The chillers are steel the piping is plastic the freezer is aluminum the belts in the freezer are stainless steel. C.D.
Last edited by CHIEF DELPAC; 24-01-2009 at 09:38 PM. Reason: spelling
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24-01-2009, 09:59 PM #6
Re: Corrosion
USIceman Your mention of old timers has got me wondering where have they all gone? Or is possible as my wife keeps telling me that I am becoming one. I think I will go with the water option as it is the easiest quickest and most important it will be the cheapest. EDDY CURRENT TESTING I was not aware of this option for testing. My limited experience in testing chillers has been pressure testing with N2 and removing tubes for visual inspection. I took a look on google and I will check it out more detail after thefreezing seasons is finished Thanks again C.D.
Last edited by CHIEF DELPAC; 24-01-2009 at 10:08 PM. Reason: added more info.
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24-01-2009, 10:52 PM #7
Re: Corrosion
Years ago I was one of the young pups the old timers laughed at. Now I'm in danger of becoming one of the old farts.
Eddy current testing is useful for testing th etubes for wall thickness, etc.If all else fails, ask for help.
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25-01-2009, 08:28 PM #8
Re: Corrosion
just to repeat what the "old timers" have already said, I mothballed a system a few years ago, I pumped out the system,pulled a vaccum of about 25"and charged with nitrogen to 15psig. the system sat idle for about 2 years and was restarted by another service tech. as far as I know it has been in operation for the last 2 years.
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25-01-2009, 08:32 PM #9
Re: Corrosion
I was speaking with one of my engineers a few months ago inquiring on how his search was going on finding a refrigeration mechanic; and his reply was he didn't want to hire a "broke down 50 year old mechanic" and I guess he saw the look on my face and stated I guess I just put my foot in my mouth. Now it is just a joke between the 2 of us, but now at least he has changed his thought process on someones age.
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25-01-2009, 10:48 PM #10
Re: Corrosion
Hey you youngsters as I am now in my seventh decade on this mortal coil I have learnt a few things . One being that people who are around my age now are not as nearly as old as when I was a young pup looking up to the old folks.However not being to old to learn I will carry on regardless.But I must say that I did not think that chiller corrosion would generate such interest.Who knew. C. D.
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26-01-2009, 06:14 PM #11
Re: Corrosion
hi all members could u pls tell me that how to protect the tube and fins type air cooled condersers from corrosion because in many places near where the sewer lines are located the copper tube get punctured very soon, can anyone give the suggestion about protection of copper tubing from this type of corrosion.
regards
gulshan kumar
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