COOLING TREATMENT
Performance Based Programs
As with our entire product line, the cooling tower programs are performance based. This means that we establish control levels on certain key parameters. These parameters can be tested for and quantified. If these control levels are meet, your results will be excellent – guaranteed.
Solutions to most common problems:
Rust Chips
White Rust
Supplemental Acid Feed
Green Towers & Expensive Biocides
CONTROL PARAMETERS
In cooling programs one of the key parameters we track is calcium. We need to account for all the calcium so the amount entering the system is the same amount leaving, a simple mass balance study. If we cannot account for it, it has most likely dropped out as scale. Listed below are our control parameters for Lake Michigan water. Do your levels match these?
PROGRAM GUARANTEE
If the control parameters are consistently met and the program has not achieved your expectations, Girard Chemical will refund the entire cost of the program. We stand behind our programs.
COMMON PROBLEMS & SOLUTIONS
At Girard Chemical we are problem solvers. Over the past thirty years we have seen most problems and have formulated solutions to these. Listed below are the most common problems observed along with their solutions.
PROBLEM – RUST CHIPS
Many cooling towers experience a problem with rust chips accumulating in the distribution pan and strainers. These rust chips are corrosion by-products of the steel piping in the system. If you stop the corrosion, you stop the rust chips.
SOLUTION – 3100 TOWER TREATMENT
The 3100 Series Tower Treatment contains a corrosion inhibitor package that is equivalent to a chrome product. This superior corrosion protection is particularly effective in preventing the formation of rust chips. We have operated this program for over twenty years and know its capabilities. At one account we solved the chip problem in three weeks time. Their problem was so bad the strainer was cleaned weekly. After three weeks of operating the 3100 program the strainer was cleaned twice and then lasted the remainder of the season.
PROBLEM – WHITE RUST
The white rust condition occurs when zinc comes out of the galvanized coating and forms a zinc hydroxide layer on the surface. This condition is a direct result of an inferior galvanized coating. White rust is prevalent in waters with only moderate amounts of calcium – Lake Michigan water. The real problem arises from the fact the zinc hydroxide does not form a tenacious bond with the metal substrate. In areas of high water flow, i.e. the distribution pan, the zinc hydroxide is continually washed away rapidly depleting the available zinc.
SOLUTION – 3400 TOWER TREATMENT
The 3400 is specifically designed to address the “white rust” condition in galvanized cooling towers. The product promotes a tenacious and stable oxide layer on the galvanizing to keep the zinc in place. What makes this program unique, besides that it works, is that it operates in an alkaline range – no acid is needed. A phosphonate/polymer blend provides the scale inhibition. This program can operate at four cycles on Lake Michigan water at a pH of 9.0.
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PROBLEM – SUPPLEMENTAL ACID FEED
Supplemental acid feed to control pH in towers is always problematic. If not properly set-up and carefully monitored irreparable damage will likely ensue. Sulfuric acid is classified as an extremely hazardous substance for good reason.
SOLUTION - 3500 TOWER TREATMENT
This acid based tower program is designed for well water make-up with high alkalinity levels. This high alkalinity increases the pH level well beyond the critical 9.0 point where scale deposition begins. Our objective is to lower the pH only slightly to about 8.8. This relatively minor adjustment offers a significant safety margin from overfeeding acid. In most cases a supplemental acid feed is not required. The 3500 contains approximately 10% acid to achieve this pH adjustment. However each account is custom blended to provide a superior program fit. An all organic corrosion inhibitor plus the high pH of the tower water combine for excellent corrosion protection. Our phosphonate/polymer scale inhibitor package can handle calcium hardness in excess of 800 ppm with no deposition. A simple mass balance analysis will indicate any drop-out. In some cases softening a portion of the make-up water provides significant advantages. In all these applications the systems need to be accurately and reliably monitored.
PROBLEM – GREEN TOWERS & EXPENSIVE BIOCIDES
You would think keeping microbio growth in check would not be difficult. In actuality it isn’t if you have a good understanding of chemistry and microbiology. Therein lies the rub for most water treatment individuals don’t have a clue. A perfect example is the continued misapplication of sodium hypochlorite as a stand alone biocide. Hypochlorite is ineffective over a pH of 8.3 while most towers operate at 9.0, so it is no wonder they are green. Give your rep our water treatment quiz and find out their real competence level. Finally governmental regulations significantly increase the cost of these products.
SOLUTIONS
There are several economical options for biocides in cooling tower. Some programs operate in grey areas with regards to the EPA. Our customers tell us this is where we do our best work – saving them money.
Bleach/Bromine
This application, for larger systems, uses two precursors, sodium bromide and sodium hypochlorite, to generate hypobromous acid – an active biocidal agent. This oxidizing program is both effective and economical and can operate at pH levels up to 9.0. The precursors are relatively inexpensive and the feed equipment for the application is simple and straightforward. The Halogenator feed system prepares a 0.2% active solution of hypobromous acid. With a 3 gpm flow rate thru the feeder a 100,000 gallon capacity tower can be slug dosed within twenty minutes. We recommend .5 ppm active for continuous dosage or 1.5 ppm for slug dosing. The program can be operated with an ORP controller and the DPD test will determine levels. This program is effective controlling Legionella bacteria. Dip slides are run periodically as one of the key parameters monitored.
Stabilized Bromine
For smaller systems where a single product program is only feasible the stabilized bromine fills the need. This strong oxidizer will control a wide range of microbiota including Legionella. The liquid material can be added by hand or by a timed pump.
DPNBA
This fast acting, wide spectrum, non-oxidizing biocide is an excellent choice for many applications including closed loops. This Dow product has been on the market many years and is a reliable means of controlling microbio growth. Another key feature is that DPNBA will penetrate biofilms.