Anti Scalent is designed as a crystallization inhibitor, dispersant and corrosion inhibitor for the treatment of open, recirculating cooling water systems containing primarily copper or copper alloys. The product is formulated with a combination of organic phosphonates, polymeric dispersants and an azole based yellow metal inhibitor. It is also frequently used in once‑through systems (may not be used in potable water) as an economical answer to the special problems associated with these systems. In certain situations, the product is also used in conjunction with various types of corrosion inhibitors.
To ensure such cooling towers are correctly maintained and operate at optimum efficiency it is essential that the correct cooling water conditions are established and then maintained at all times. This can be achieved using carefully selected cooling tower water treatment chemicals.
Cooling water treatment is mandatory for any cooling tower whether with splash fill or with film type fill for controlling suspended solids, algae growth, etc. With increasing costs of water, efforts to increase Cycles of Concentration (COC), by Cooling Water Treatment would help to reduce make up water requirements significantly. In large industries, power plants, COC improvement is often considered as a key area for water consumption.
Wetco’s comprehensive range of high performance cooling water treatment chemicals have been scientifically formulated to deliver significant operational benefits and performance improvements to cooling towers, and open and closed cooling systems that use water as a primary coolant.
- Anti Scalent
- Biocide
- Water Dispersant
- Anti-corrosion
This product is a unique, polymerized quaternary EPA registered biocide for use in controlling algae, bacteria, and fungi in recirculating cooling water, air washer systems, and decorative fountains that DO NOT CONTAIN FISH. The product is effective in controlling these microorganisms over a wide pH; particularly in the lower hardness waters. Unlike most similar products, at normal use concentrations, it will not cause foaming in the treated systems.
Cooling water dispersant contains surface active agents effective for use as a bio penetrant and organic slime/silt dispersant in cooling water systems. It is especially effective for cleanup of slime masses resulting from bacterial biofilms. Its surface active and hydrophobic properties aid maintenance of clean surfaces and inhibition of corrosion. It is highly effective as a penetrant when used in combination with chlorine and/or bromine based biocides or other biocides not possessing surface activity. Dispersant are designed to be used in combination with an effective biocide program to help maintain cleaner heat transfer surfaces and improve control of bio fouling.
Molybdate is classified as an anodic, oxidizing inhibitor. Molybdate is not effective in the absence of oxygen, but works in conjunction with oxygen to form a protective oxide layer on ferrous metals. As ferrous ions are formed at the anode (Fe0 → Fe+2 + 2e-), molybdate ions react with the ferrous ions to form a non-protective ferrous molybdate complex. This complex is then oxidized by dissolved oxygen to form an insoluble and protective ferric molybdate complex in combination with ferric oxide. Furthermore, molybdate is believed to strengthen the outermost hydrated iron oxide layer by hydrogen bonding to hydroxide groups on the surface thus imparting a negative surface charge which impedes aggressive chloride and sulfate ions from approaching the metal surface and ferrous ions from leaving the metal.7 Lastly, molybdate helps to retard the growth of pits because as a break in the protective film occurs, absorbed molybdate is released and concentrates inside the pit precipitating as either FeMnO4 or as a condensed molybdate species.
In addition to use for ferrous metal corrosion control, molybdate is commonly used as an aluminum corrosion inhibitor. However, the mechanism for aluminum corrosion control is much less defined, but molybdate is believed to be incorporated into the protective film as a hydrated aluminum molybdate
Nitrite is an oxidizing, anodic inhibitor that has been in use for many years. With the present high cost of molybdate, nitrite is often the most effective and least expensive option for controlling mild steel corrosion, when no other factors prevent its use. Nitrite works by promoting the formation of a passive γ-Fe2O3 film by the following reaction
4Fe + 3NO2- + 3H+ → 2γ-Fe2O3 + NH3 + N2
Unlike molybdate, nitrite does not need the presence of dissolved oxygen.
