Cooling Tower Cleaning

if its steel with a galvanized coating and you have scaled it up you basically need to budget for a replacement, you've already lost the tower, if the tubes are copper you can "rod" the tower and knock the scale off, then finish with chemicals, it sounds like your monthly water treatment was a fail. your tower should never be allowed to scale

In the best of worlds, yes the tower must never scale, but they almost always eventually do, for one reason or the other. The challenge is to know what the scale is going to be before you have to remove it. I have seen a struggle to remove a scale that basically resembled concrete that went on with management for over 15 years, until I finally proved to them I could totally remove that scale even from oil coolers with high temperature gas turbine oil, direct primary coolant contact, and 60% tube blockage! Concrete remover really works! Best to test various suppliers formulations on small areas first.

Also good to have a Goodway lumen water jet drill with tungsten carbide tip for those pesky 1/4" tubes that block so easily! Once the concrete remover chemical can contact the scale (wet it all the way the length of the tube), even the worst scale will come off.

For efficiency sake, never allow the scale to reduce the surface condenser efficiency below about 50% of factory new U value. One can calculate the U value based on operating data, determine the fouling factor from that, then also determine % efficiency of cooling (i.e. 70% or better), and if the mineral scale analysis is known, one can provide a linear combination of known heat transfer coefficients for minerals that substitute for the "unknown-known" mineral, and come out really close to the scale thickness in fractions of a mm. At least I have a model for that, even on a fairly small generating unit of only 40 MW. Other coolers in process such as oil coolers and hydrogen coolers, especially extreme stress ones like gas turbine oil coolers or compressor inter-coolers must be on secondary loop water that is controlled chemistry. I have seem dumb bunnies do it the hard way though for years.

Don't do it, Mildred! Buy-in the service you require from a specialist company!

Also, buy-in a treatment regime, specially designed for your water, to keep the tower so clean it doesn't need periodic cleaning. If you're not already doing it, then shut the tower down until you have. No-one wants unwanted biology rampaging around the district!

Yes, when in doubt, get outside experts help. While you may find someone here(CR4), they will likely not be fully aware of all your system and are giving their "best" guess based on the facts provided, which, as we are all aware, are usually insufficient for a definitive answer.

Vinegar or a popular cola beverage will work.

What kind of cooling tower are we talking about? Is this a power plant tower 4 stories tall and longer than a football pitch or is this one of those fiberglass mushroom cap looking ones?

A very safe, but long term approach would be to use demineralized water and allow it to dissolve the minerals for you.

Since you have steel pipes, don't forget to check on your anodes, and if you don't have any, get some to keep the pipes from rusting.

Drew K

Cooling tower maintenance is very complicated,requiring constant checks of

Ph,mineral content,water conductivity,algae,and other factors.

Simply adding acid will not solve all of the problems.

Water conditions vary widely from location to location,and there are too many

variables for a one-size-fits-all solution.

Your tower can actually dissolve or melt down due to improper chemicals in the

water.

You have more problems than scaling inside of your pipes.

Aluminum will dissolve over time,especailly if Ph is not controlled.

There goes your tower!

The old redwood towers were the best for durability,but you still had to take care of

the water conditions for the pipes' sake.

Hire a professionsal cooling tower maintenance company to take care of it.

It will be money well spent,compared to replacing the tower.

Good luck!

You must relay on a knee-jerk, or from the hip answer found here. If hiring a metals cleaning company for removing scale from condensers, they will want to know a minimum of the following:

(1) The water chemistry and cycles of concentration by evaporation.

(2) Information about all metals involved or in contact with your condenser, any oil coolers, hydrogen coolers, etc. that may become involved in, or need this same cleaning.

(3) Clearance from your insurance carrier, but they will gob-smacked when learning how badly scaled up all your equipment is.

(4) How old the condenser tubes are, and how badly corroded they are, and I suspect you may in trouble there. If the metal is already showing condenser leakage into the condensing side of the surface condenser, the cleaning will open up even more tubes. Get ready for a general tube replacement.

(5) If you have: (a) Calcium Carbonate scale (40% calcium by analysis), then you might use glycolic acid with a good phosphonate based iron corrosion inhibitor, but I will not tell you dosages, only for a mild steel only system., (b) if you have calcium sulphate scale, this one is harder to remove, and requires chelant, and very high chloride levels with a strong acid inhibitor for the steel, (c) if the scale is silica (glass-like, or even like grains of sand stuck to tubes), then you have a real problem, this requires proprietary fluoride based cleaning, and is done only by certified professionals, since the average joe will poison himself trying this. (d) if the scale looks like Portland Cement, even though it is thin, is hard as cement, and has the same analysis as Portland Cement, you will need a proprietary (purchased) concrete remover formulation (and there are many), but these will work well as long as good contact with made between the scale and the cleaning solution. Usually foaming applications work as well or better than merely liquid being pumped through.

That in a nutshell is the wealth of my experience with scale removal. Remember to always check the formula for compatibility with the actual metals it will contact, and if at all possible pre-test the cleaning on some exemplars that are scaled, but outside the system if at all possible to do so.