Scale cleaning on condensers with iron-calcium-magnesium-aluminum silicate
Scale cleaning on condensers with iron-calcium-magnesium-aluminum silicate
(OP)
Very complicated scale analysis, but the analysis reminds me of montmorillonite clay, also portland cement.
I tried about every sort of acidic cleaner in the known universe (short of hydrofluoric acid, which I refuse to deal with), then realized we had a quantity of concrete tool cleaner. I tried it on a section of stainless steel tubing 5/8" OD that was heavily scaled with this material. In fifteen minutes, the scale was sloughing off the tube and dropping to the bottom of the graduated cylinder.
We have purchased some concrete remover, and had other samples sent. All of them perform moderately well in the cleanings we have undertaken thus far on oil coolers both for steam turbine oil cooling, and one that was badly scaled with small 1/4" or less diameter tubes that was the scavenge oil cooler for an LM6000 gas turbine. No complaints thus far.
I tried about every sort of acidic cleaner in the known universe (short of hydrofluoric acid, which I refuse to deal with), then realized we had a quantity of concrete tool cleaner. I tried it on a section of stainless steel tubing 5/8" OD that was heavily scaled with this material. In fifteen minutes, the scale was sloughing off the tube and dropping to the bottom of the graduated cylinder.
We have purchased some concrete remover, and had other samples sent. All of them perform moderately well in the cleanings we have undertaken thus far on oil coolers both for steam turbine oil cooling, and one that was badly scaled with small 1/4" or less diameter tubes that was the scavenge oil cooler for an LM6000 gas turbine. No complaints thus far.





RE: Scale cleaning on condensers with iron-calcium-magnesium-aluminum silicate
Yes, often chemical cleaning is needed. Some of the foaming cleaners are nice because they lift debris from the surface. Chemical cleaning in a mixed metallurgy system often comes down to doing the least harm.
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P.E. Metallurgy, Plymouth Tube
RE: Scale cleaning on condensers with iron-calcium-magnesium-aluminum silicate
RE: Scale cleaning on condensers with iron-calcium-magnesium-aluminum silicate
I have had experience in the past where sample coolers on boilers were set up by an instrument tech at a customers facility, where the coolant applied was untreated city potable water (high chloride content in the local water), and within a week the boiler sample cooling coils had fractured. Those were all 316 stainless steel.
Things that were tried before with NO effect on the scale: (1)citric acid, (2)hydrochloric acid, (3) acetic acid, (4)glycolic acid alone.
These concrete removers have a mysterious something else in them (perhaps a zwitterion?) that is extremely effective in peptizing concretions.
RE: Scale cleaning on condensers with iron-calcium-magnesium-aluminum silicate
I have tried over and over to get one of the OEM's of that equipment to make a tool that will allow the same on oil cooler and condenser tubes. I am pretty sure that sudden chilling of the deposits (with the sudden shrinkage in dimensions) will result in powderization of the concrete-like scale deposits, along with any metal oxides, and clean the tubes down to bare metal, no corrosion. The tubes would be air blown to dryness first, as is about typical in most outage inspections.
I should probably take this idea to one of the tube cleaner companies out there. The problem getting a big slot in the market is the vested interest these companies have in cleaning the way they are now, and convincing their customers that is a good cleaning, and the vast majority of sites where the only type of scale that forms is calcium carbonate scale that is paper thin, and very easily removed. The stuff I have been referring to is difficult to even sample with a knife edge scraper bent 90 degree to its length to reach in and scrape the inside of a tube.
RE: Scale cleaning on condensers with iron-calcium-magnesium-aluminum silicate
RE: Scale cleaning on condensers with iron-calcium-magnesium-aluminum silicate
There is something in the concrete remover product (or the overall formulation) that seems to destabilize ionic attraction between local crystalline zones.
RE: Scale cleaning on condensers with iron-calcium-magnesium-aluminum silicate
RE: Scale cleaning on condensers with iron-calcium-magnesium-aluminum silicate
Variation of phosphoric acid derivatives mixed with chelating agents is what makes these work.
Either move to treated water, or lower the pH with sulfuric acid.
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P.E. Metallurgy, Plymouth Tube
RE: Scale cleaning on condensers with iron-calcium-magnesium-aluminum silicate
The scavenge oil cooler mentioned is stainless steel 316. No cracks in the metal (yet).
I already told management a long time ago we would have problems on this cooler if we did not put in on secondary loop (i.e. a closed loop) with either air cooling, or secondary heat exchange with plant cooling water from cooling tower (once the temperature is lower it is not nearly as big a deal).
RE: Scale cleaning on condensers with iron-calcium-magnesium-aluminum silicate
Agree better to transfer these oil coolers to some closed loop treated water cooling system with low TDS since these are in critical service.
RE: Scale cleaning on condensers with iron-calcium-magnesium-aluminum silicate
RE: Scale cleaning on condensers with iron-calcium-magnesium-aluminum silicate
RE: Scale cleaning on condensers with iron-calcium-magnesium-aluminum silicate
RE: Scale cleaning on condensers with iron-calcium-magnesium-aluminum silicate
RE: Scale cleaning on condensers with iron-calcium-magnesium-aluminum silicate
https://www.youtube.com/watch?v=_eGUMRCm-Xg
RE: Scale cleaning on condensers with iron-calcium-magnesium-aluminum silicate