Posted 12 April 2012 - 10:06 PM
Posted 14 April 2012 - 12:43 AM
If he agrees to that, your problem becomes simpler. Now you only have to treat it for corrosion. If there are no yellow metals in the system, you can use either catalyzed sodium sulfite or erythorbate. I would use both in a blend with enough caustic to keep the pH around 8.5 to 9.0. You need to know how much dissolved iron is in the system water BEFORE raising the pH, since raising the pH can create iron hydroxides which revert to oxides. These could then destroy pump seals and pump impellers. You should also have side stream filtration on this system capable of down to 5 micron filtration capacity. That will be needed during pH elevation, particularly if dissolved iron is currently present.
If he will not soften, then you need to keep the pH to 7.5 to 8.0 to balance the corrosion on iron versus the scaling potential. You need to use some polymers (probably even a good idea if he does soften). I would recommend some terpolymers for iron and some polyacrylate. Probably 5 to 10 ppm of each should do. Phosphontes could be added. I would recommend 5 to 10 ppm as HEDPA. USE ONLY PHOSPHONATES THAT ARE STABLE TO CHLORINE, because at those temperatures you will begin to experience some phosphonate reversion to ortho phosphate. Ortho Phosphate is not a concern in a boiler program, since the high pH will result in hydroxyapatite formation. At this pH tricalcium phosphate will be formed.
If there are yellow metals present you will need to use azoles. This could get tough. High concentrations of 50 to 100 ppm are advisable.
You need to be checking copper and iron in the loop versus the make up water.
PROTECT YOURSELF LEGALLY. It is far from certain that any of this will work. You will need to constantly check for corrosion products and scaling potential, so you can make adjustments in the program. I would strongly urge that you have one of their corporate officers sign a legal document agreeing to hold you harmless, since they are so far away from accepted procedures. Without some sort of hold harmless agreement you may just want to walk away from this one. No point in being sued.
A conventional borate-nitrite treatment could be far cheaper if he would/could close up the system.
Is the 2000 gallon per day loss necessary?
Did anyone treat this before you? What did they do and how did that work?
How is he keeping the expansion tank from filling up with gasses? That should become a major problem at those temperatures and that make up level.
Posted 21 November 2012 - 09:35 PM
Tim Keister, CWT
Posted 24 November 2012 - 04:13 PM
Tim, unlike the Association of Water Technologies (AWT) ListServ, we allow shameless self promotion here. LOL.
BTW: We are also not afraid to host postings from Nalco and GE Water Personnel...unlike the Association that calls itself the "Voice of the Water Treatment Industry".........unless you have over 30 million in sales.
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