Cooling System Scale & Corrosion Inhibitors

The unwanted accumulation of scale and detrimental impact of metallic corrosion can be significant issues that affect the operation and maintenance of open and closed cooling water systems including evaporative condensers.

Cooling System Scale & Corrosion Inhibitors

To ensure that open and closed cooling systems are well maintained and operate at optimum efficiency it is essential that the correct water conditions are maintained at all times.

This can be achieved using carefully selected scale and corrosion inhibitors designed specifically for such cooling systems. Our scale and corrosion inhibitors deliver improved performance, helping to reduce maintenance costs, improve reliability and optimise operational efficiency.

If you are a water treatment specialist, FM or maintenance company who regularly resells water treatment products to your customers why not apply to become an Accepta Registered Reseller.

How Accepta Inhibitors work

Accepta’s range of cooling water inhibitors work by in two main areas; firstly film forming components create a protective layer on the metal surfaces preventing electrochemical attack which leads to corrosion and weakness in the cooling system.

Corrosion Protection
Scale Disruption

The scale inhibiting and anti-foulant components then keep suspended solids moving freely and prevent insulating scale deposits forming on heat transfer surfaces by disrupting scale formation in both our Bromgard and Coolguard inhibitors ranges.

The Bromgard Range

Bromgard is a two part chemistry where the Scale & Corrosion Inhibitor also contains a Bromine pre-cursor. 

When using Bromgard chemicals the bromine pre-cursor will be continuously maintained within the water system.

The biocidal power of bromine is then release by the controlled addition of an oxidising solution such as Activator 120 which then forms the correct concentration of Bromine within the system with no risk of halogen lockout.

Watch the full Bromgard video above to find out more.

Bromide to Bromine Conversion
Recommended Operating Ranges
Codes
Description
Calcium Hardness Range
pH
Total Alk
Target Cooling Water Ryznar Index

Phosphate based corrosion and scale inhibitor for low hardness. Very good at high temperatures.

20 - 200

Recommended Operating Range:

20 - 200 CaCO3

6.5 - 8.5 pH

<200

Total Alkalinity <200

>7 RSI
Light - Heavy Corrosion

Zinc based multi-functional corrosion and scale inhibitor and bromine precursor. For soft to medium hardness waters.

0 - 300

Recommended Operating Range:

0 - 300 CaCO3

7 - 9.5 pH

<300

Total Alkalinity <300

>6 RSI
Light - Heavy Corrosion

Blend of organic inhibitors for use where heavy metals or phosphates are restricted. For medium to high hardness waters.

200 - 600

Recommended Operating Range:

200 - 600 CaCO3

7 - 9.5 pH

200 - 600

Total Alkalinity 200 - 600

<7 RSI
Heavy Scale - Light Corrosion

BG520

Heavy metal free, silicate based blend of inorganic and organic scale and corrosion inhibitors. Great environmental profile.

50 - 400

Recommended Operating Range:

50 - 400 CaCO3

7 - 9.5 pH

<300

Total Alkalinity <300

5.5 - 8 RSI
Light Scale - Heavy Corrosion

BG2850

Concentrated alkaline blend of scale and corrosion inhibitor including phosphonate.

300 - 600

Recommended Operating Range:

500 - 600 CaCO3

7 - 9.5 pH

200 - 600

Total Alkalinity 200 - 600

<7 RSI
Light Scale - Light Corrosion

BG110

Molybdate based scale & corrosion inhibitor for soft to medium hardness water. And applications with low cycles of concentration.

20 - 300

Recommended Operating Range:

20 - 300 CaCO3

7.5 - 9.5 pH

6 - 9 RSI
Light Scale - Heavy Corrosion

Activating halogen donor for use with Bromgard inhibitors to produce bromine biocide in-situ.

When using Bromgard products a bromine pre-cursor is continuously maintained in the system water. The biocidal power of bromine is released by the controlled addition of an oxidising activating solution that activates the precursor to form the correct concentration of bromine. The activating solution also contains a bio-dispersant that ensures effective penetration of bromines into existing biofilms, Control of the addition of the activating solution is preferably by a redox probe and controller linked to an injection pump, see Coolplex Control Unit for superior Bromgard control.

Bromgard products and a redox control system provides the most cost-effective solution to the use of bromine in a cooling water system.

In some applications, a secondary non-oxidising biocide may be recommended.

 

Non-bromine multifunctional inhibitors

Each of these popular inhibitors is a multifunctional blend which includes both scale and corrosion inhibitors for steel, copper and brass as well as polymer dispersants to prevent fouling, these provide powerful treatment to inhibit scale or corrosion but do not contain a bromine precursor. A stand alone biocide will be needed.

Recommended Operating Ranges
Codes
Description
Calcium Hardness
pH
Target Cooling Water Ryznar Index

A blend of organic inhibitors for use where heavy metals or phosphates are restricted. Intended for medium to high hardness waters.

300 - 600

Recommended Operating Range:

300 - 600 CaCO3

4 - 6.5 pH

4 - 6 RSI
Light - Heavy Scale

A novel alkaline zinc phosphonate based multi-functional corrosion and scale inhibitor. For soft to medium hardness waters with low alkalinity.

0 - 300

Recommended Operating Range:

0 - 300 CaCO3

6 - 9
Light Scale - Heavy Corrosion

Low dose rate organic inhibitors for use where heavy metals or phosphates are restricted. Best for high water loss systems. Low/med hardness waters.

300 - 800

Recommended Operating Range:

300 - 800 CaCO3

4 - 6.5
Heavy Scale - Light Corrosion

A silicate phosphonate based scale & corrosion inhibitor for soft to medium hardness water and where heavy metal use is restricted.

50 - 400

Recommended Operating Range:

50 - 400 CaCO3

5.5 - 8.0
Light Scale - Heavy Corrosion

A phosphate based corrosion inhibitor for extremely corrosive waters. Can be used in pasteurisation systems w/high temperatures & chlorine levels.

20 - 200

Recommended Operating Range:

20 - 200 CaCO3

7 - 9.0
Light - Heavy Corrosion

Molybdate based scale & corrosion inhibitor for soft to medium hardness water. Also suitable for strainer cycle applications with low cycles of concentration

20 - 300

Recommended Operating Range:

20 - 300 CaCO3

5.5 - 8.5
Light Scale - Heavy Corrosion

Water Corrosion or Scale deposition tendency

Professor Langelier’s research, complete in 1936, defines conditions in which water is balanced with calcium carbonate, making it possible to predict the likelihood of a given water to either precipitate or dissolve calcium carbonate. Being the universal solvent that it is, if water is out of balance, it will seek to find its own equilibrium (0.0 LSI.) in the case of swimming pools, water can even draw calcium out of the plaster that lines the pool walls,  or in industrial systems draw from the protective coating on pipework at an LSI of -0.5 LSI and below. In the case of over-saturation eg. >0.5 LSI the water will become scale forming.

The relationship between the actual pH of a water sample and the pH at which it is just saturated with calcium carbonate (pHs) is called the Langelier Saturation Index (LSI) and is equal to (pHs – pH).

However, the way in which the LSI is calculated, two different waters; one having high levels of hardness (scale forming), and the other with low level of hardness (corrosive) could theoretically have the same Langelier Saturation Index (LSI) due to the effects pH, Alkalinity and Temperature have on the calculation. For this reason we reach for the Stability index developed by Ryzner (RSI) which goes further and distinguishes between two waters based on an index of actual operating results with waters of various LSIs.

The RSI of water is calculated by: 2 x pHs – pH

The results can be interpreeited according to the following guidelines:

Ryzner Stability IndexTendency of Water
4.0 – 5.0Heavy Scale
5.0 – 6.0Light Scale
6.0 – 7.0Light Scale or Corrosion
7.0 – 8.0Significant Corrosion
8.0 – 9.0Heavy Corrosion
Above 9.0Intolerable Corrosion

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