The Basics of Water Treatment for Cooling Towers
Cooling towers are integral pieces of equipment to many businesses today, allowing companies to remove heat from their environments to cool down their buildings and processes. These specialized heat exchangers run on the principles of water-cooling methods and, as such, need proper water treatment in order to keep costs low and maintain high cooling efficiencies.
Without treating your cooling tower water, you run the risk of corrosion, scaling, and microbiological buildup. These issues can reduce plant productivity, cause unplanned downtime, and require costly equipment replacements if conditions get out of control. That’s why everyone who uses a cooling tower needs to treat their water.
Water Problems and Cooling Inefficiencies
With the mechanism of using water to remove heat from your systems, cooling towers are subject to a number of operating problems. These include:
- Microbiological deposits
- Mud and grime
- Scale deposits
Microbiological Deposits and Mud/Grime
A large source of cooling tower fouling, microbiological deposits like fungi and algae can form slimes on the important heat transfer surfaces of the tower, leading to significant cooling inefficiencies. These deposits can become so abundant in cooling systems that they obstruct the free flow of water and air, weighing down the structural members of cooling towers and potentially causing them to break. Similar issues can occur with any mud or grime that forms within the tower.
Scaling can occur when the concentration of a dissolved substance becomes greater than its solubility in the water. This is especially an issue with materials whose solubility goes down as the temperature rises. Calcium sulfate, calcium phosphate, and other calcium salts commonly cause scale, as well as certain materials at high concentrations, such as silica or silicates. Any scale that forms will impact heat transfer, lowering the cooling efficiencies of the tower.
Corrosions is always an issue in any water-handling system where the water comes into contact with metal. In open, recirculating cooling water systems, the concentration of electrolytes caused by evaporation can increase the corrosiveness of the water. Maintaining reduced pH values – which is a means of scale control – can also accelerate corrosion.
Though not as common as other cooling tower issues, foam can occur in some systems from the cascading water in the cooling tower. This can overflow the cooling tower sump with foam or cause the fans to blow foam out of the top of the tower. Foam also has a tendency to concentrate deposit-forming materials, thus increasing the fouling of the system.
How Water Treatment Works for Cooling Towers
While the specific means of water treatment will vary from one application to the next, typical cooling tower water treatment will cover one or more of the following areas:
- Treating makeup water
- Chemical treatment
- Side-stream filtration
Treating Makeup Water
Makeup water – the water needed to replace evaporated and leaked water from the cooling tower – often needs to be treated before it is added to your system. Depending on the quality of the water source, this can involve removing hardness or silica, as well as adjusting the pH levels of the water.
By running your cooling tower water through some type of filtration equipment, you can remove suspended particles and certain types of organic matter that can contribute to scaling, corrosion, and foaming. You typically want to do this in the beginning of your water treatment since removing suspended solids upstream can help protect ion exchange resins and membranes from fouling later on.
Chemically treating your water is important in order to balance the chemical properties of the water itself, making it less prone to causing issues. Standard chemical treatments include:
- Water softeners and ion exchangers
- Corrosion and scale inhibitors
- Algaecides and biocides
- Anti-foaming agents
- pH adjusters
With a full stack of quality chemicals, you can not only mitigate any water-related issues, but also optimize the other stages of your water treatment.
If you plan on recirculating your cooling tower water throughout your system, side-stream filtration units can help to remove any pollutants that may have entered your tower through drift contamination or process leaks. Side-stream units continuously filter your cooling tower water in small increments to remove suspended solids, organic deposits, and silt particles. This reduces the likelihood of any fouling or biological growth, resulting in both water and energy efficiency gains from less water having to be discharged and less scale formation on any heat transfer surfaces.
The ChemREADY Advantage
With significant experience across every major cooling application, ChemREADY is your go-to partner for cooling tower water treatment. More than just a supplier, we offer the best chemicals available along with our industry-proven expertise to make sure that your water is treated the right way.
If you want to learn more about how we can help with your cooling tower water treatment, or you’d like to discuss your needs in detail, contact the ChemREADY team today.