Removal of scale from copper pipe in a cooling tower?

OK, go ahead. _{Where's Vader when you need him?}

This may help:

Copper.org: Copper Tube, Pipe & Fittings: Technical References ...

I have used Saf Acid. It has a color indicator and does a good job removing scale, by circulating a solution, or immersing the object (like a heat exchanger) in the liquid and agitating with air or mechanical means. It is user friendly, just take usual precautions. Here's the MSDS for Saf Acid Descaling Compound.

http://hazard.com/msds/f2/byf/byfbp.html

Some more info:

Common problems with copper pipes:

Soft water, or water with a pH below 7, is acidic. This acidity will dissolve copper pipe walls and cause leaks to break through. In hard water, or water with a pH above 8, scale builds up on the walls of the pipe will eventually lead to pitting, which will then lead to pinhole leaks.

Poor quality materials and poor installation can also be a cause of copper pipe leaks. A copper pipe with "cold bending" weakens the copper at the bend and water will erode the pipe material, eventually causing leaks.

Not to question your answer, but could you please explain the ph of soft water?

As I understand from my chemistry class, water dissolves other substances due to the polar nature of H₂0 molecules. Hard water is already saturated with foreign material that precipitates out to cause scale, doesn't soft water dissolve that scale that built up? I know copper will oxidize, but is it the soft water or something else dissolved in the water that raises the ph level?

Drew

(an engineer in training, definitely not a chemist )

The only thing that raises the pH is dissolved alkaline species.

For the origianl poster: softened water is better for cooling tower systems, though not a prerequisite. In the end, it's all about the chemical treatment regime, which needs to be discussed with a specialist locally, for water in one location is never the same as the water in another.

Water containing sodium or potassium hydroxide has a high pH but it is still soft. Hard water contains dissolved calcium or magnesium. Hard water always has a high pH, but just because the water is soft does not mean that it has a low pH.

Some really good info in this thread. There is soft copper, comes in rolls, you bend it to the job. There is hard copper, comes in straight pipes, doesn't like to bend. Soft copper will work harden, you only get so many tries, then it snaps, or gets so hard you can't bend it easily. How is a guy to know which is best for plumbing what?

I recall my chemistry teacher talking to us about hard water. He said that even if the pipes in your house were really bad off due to scale build up inside that installing a water softener could reverse the process and remove the scale from the pipes. He said that if it took 20 years for the hard water to deposit the scale in the pipes that once you start putting soft water in the pipes they will dissolve the scale. It didn't matter how bad it was, as long as soft water passes scale deposits it will eventually dissolve.

But he also lectured us for 20 minutes on the health benefits of farting, and never once mentioned that farts held in turn into crappy idea!

I am by no means an expert, I like PWSlack's idea of contacting a local expert.

Drew

There are health issues with consuming softened water long-term, owing to the higher-than-usual levels of sodium in the softened water. Also, the calcium level in water for consumption should be maintained above 60ppm or so for health reasons.

If the scaled-up system is not intended for consumption then softened water is not an issue. Over time, the scale may redissolve.

Hi Guest,

Good advice in general, it all depends on how desperate you are to remove the scale. If it is impeding flow then it must have reached a substantial thickness, can you comment?

Having had dealings with water treatment specialists down the years I am rather sceptical of their 'solutions' in respect of eliminating this problem. I've paid a lot of money and seen only mediocre results BUT there is one product (not for the faint hearted) which really does work. Its called 'Clensol' and is basically hydrochloric acid which converts lime scales into the chloride plus CO2; you circulate the brew for long enough to clear the thickest deposits. As a guide when the water returning to the break-tank loses its milky appearance either the pipes are clean or the acid is spent. Dip tests can confirm the residual pH. Do not use in any system which has galvaised surfaces or they will go as well.

Clearly once you've chosen a product and then got things improved you will want to keep it that way and therefore a water treatment regime to avoid the deposition of scale is essential.

I am surprised that as part of your 'Legionella' control measures that this issue has not been addressed. I would insist that the water management regime addressed this issue as you are otherwise at risk of creating the ideal environment for the proliferation of this bug.....V.nasty consequences potentially!

Anyway check out a strong acid cleaning agent but be aware of consequences for some of the metals in your system.

Regards,

Massey.

The following scale removal treatment may be of interest, as we have found to be effective on copper pipe. The ECO 2000 Mineral Binding System (electronic descaler) creates an induced signal that increases the electrical charge of the positive (e.g. calcium carbonate) and negative (e.g. calcium bi-carbonate) ions. Increasing the positive and negative charges cause these molecules to bind together forming seed crystals, which lose their natural tendency to adhere to the walls of the plumbing system and machinery. In addition, these crystallized molecules fall out of suspension, refreshing the water's capacity to reabsorb calcium carbonate. This renewed capacity allows the water to methodically clean out existing scale formations. Although non-chemical water treatment has a controversial history, we've conducted a number of independent chiller audits and demonstrated energy savings of 10% - 40%. This is accomplished with non-chemical treatment in conjunction with other technologies such as high-efficiency filtration. There was also 75% water savings. In most cases, there was less than a 12 month payback. I'd be happy to email case studies if interested.

I don't want o see case studies, I want you to explain how electricity can affect the electron bond of a dissolved mineral in water. I understand how electricity can break the bond of water and hydrogen (sort of) but not how an induced signal can have anything to do with dissolved minerals.

Save the 'case studies' and testimonials for the infomercials.

Drew