Amiad Water: Choosing the Best Cooling Tower Filtration System

Industrial manufacturing facilities typically require cooling equipment to cool chillers, heat exchangers, products, and other devices, and this equipment must be protected from contaminants in the cooling water.

In addition, environmental regulations for source water protection require manufacturers to return used cooling water to its source in a non-polluting condition.

Cooling tower filtration systems are essential to secure equipment and comply with these regulations.

Here are some other valuable benefits of cooling tower filtration:

• Improved heat transfer rates in the water cooling system for a longer period

• Reduced water consumption

• Improved chemical efficiency

• Reduction of chemical consumption

• Reduced maintenance and energy costs

• Increased equipment life

What is water filtration for cooling towers?

The aforementioned regulations require that cooling systems be chemically treated and monitored regularly, especially for corrosion, scaling, suspended solids and biofouling.

Corrosion, scaling and biofouling can be controlled by routine water treatment, but suspended solids can be more difficult as they can reach the system in a variety of ways, such as production contaminants, corrosion of pipes and variations in the composition of the raw water. Airborne particles are also a problem and in some cases can lead to high dirt loads. If left untreated, suspended solids can lead to poor energy transfer and clogging and negatively affect the effectiveness of chemical treatment. In severe cases, suspended solids can lead to costly replacements, and production efficiency and productivity would be affected if the system had to be shut down for repair.

Filtration plays an important role in cooling tower protection and falls into 3 categories: side-flow water filtration, full-flow water filtration, and make-up water filtration.

Side-flow water filtration:

A percentage (5-15%) of the recirculating cooling water volume is circulated in a water loop, reducing the overall solids load. This loop then passes through a filtration system.

Full-flow water filtration:

A filtration unit is installed on the discharge side of the pump, after the cooling tower, and continuously filters all recirculating water in the system.

Make-up water filtration:

Water is lost during the cooling process and the make-up filtration process is used to replenish the reservoir of water used for cooling. There are four reasons for this water loss:

• Natural evaporation

• Blowdown/Bleeding: to reduce salinity and particle concentration

• Drift: mist and/or tiny drops of water in small amounts may be carried from the cooling tower, but the loss of water is less than during blowdown and evaporation.

• Basin overflows or leaks: Cooling towers should be examined and properly maintained to prevent overflows and leaks.

Cooling Water Filtration Technologies

Making an informed decision about which filtration technology is right for your system is essential. It is important to understand the general application requirements, including degrees of filtration, as well as review the advantages/disadvantages and costs of each technology.

Centrifugal Separators

Centrifugal separators, also known as hydrocyclones, use centrifugal forces to separate heavy solids larger than 70 microns from water. They are frequently used with a filtration system which can remove finer particles, but centrifugal separators do not stop organic particles.

Traditional sand filters

Sand/media filters route cooling water to the media bed. There are different types of filter beds, such as sand, crushed glass, basalt, etc. As the water passes through the bed, the particles are trapped and the filtered water then goes to the bottom of the tank to be discharged through the outlet.

Automatic screen filters

Automatic screen filters use multiple screens that trap suspended solids in the cooling water as it passes through them. The filtered water then flows through the filter outlet. The gradual accumulation of dirt (cake) on the surface of the inner screen begins the cleaning process.

Polymer disc filters

Disc filters consist of a series of grooved flat discs which are stacked under pressure. As unfiltered water flows through the discs, it traps particles. As more particles are trapped, the filter pressure difference increases, which begins the cleaning process.

Cartridges and bag filters

Cartridge and bag filters are flexible solutions for side filtration. However, they are consumable and require manual replacement. This needs to be considered as the disposable nature of these filters will increase expense over time.

High efficiency media filters

Like the sand filters mentioned above, high efficiency media filtration uses sand and crushed glass as the media, but the characteristics of the sand differ here. Another difference is the cross-flow patterns produced by the water injectors, sweeping across the surface of the media bed. This causes some of the water to flow parallel to the top layer for submicron filtration and prevents media clogging and channeling through the media. Contaminants inside and on the rack are removed by an automatic backwash cycle.

Lateral Flow Filtration System Features Review

(Click on the image to enlarge):

Why water cooling is so complex

Water cooling poses four significant challenges and if left unchecked, over time, all can reduce performance and efficient energy use.

1. Biological contamination: By design, the temperature and humidity of the cooling tower environment are high, making it an ideal breeding ground for bacteria. Even the slightest buildup of biofilm inside components can significantly reduce effectiveness.
2. Corrosion: When air, sodium, and additional chemicals in the water are left unchecked, they can erode metal and lead to leaks in equipment throughout the process and in cooling towers.
3. Dirtying : When dirt, dust and/or debris clog cooling surfaces or pipes and water cannot circulate as needed, the air is not being cooled as needed. This leads to wasted energy as the system works harder to achieve the same result.
4. Scaling: During the heat exchange process, various minerals, such as calcium, can build up on the heat exchange surfaces, creating layers of scale. If not removed, scaling will increase operating costs.

Choose the right one Cooling tower filtration system

Here are some factors to consider when determining which type of cooling tower water filtration would best meet the requirements and provide the best filtration performance:

• Site: Where in the cooling process will the filtration system be installed?
• Footprint: Are there any limitations on installation space?
• Debit: What is the throughput of the system? Is the preferred pressure variable or stable?
• Filtration degree: What is the size in microns of the particles to be filtered?
• Particle characteristics: Sand, seaweed, etc.
• Costs (purchase, maintenance, operation, backwashing, energy): Knowledge will help decision-making.

Amiad Cooling Water Filters

Amiad’s filtration solutions and technologies help maintain good water quality, improve heat transfer efficiency, reduce operating costs and are ideally suited to help meet application challenges. following cooling water:

• Spray tip filters for tip protection

• Lateral flow filters for cooling towers

• Full-flow cooling systems

• Upstream filtration – exchanger protection

• Condenser and chiller loop protection

• Composition of the cooling tower

With a comprehensive product line and various filtration technologies – screens, discs, centrifugal separators, media and high-efficiency media – Amiad offers custom solutions for the harshest environments, variable water conditions and demanding technical requirements.

You can learn more about how the filtration solution for cooling tower water treatment was implemented in our case study: Cooling Tower Filtration for an Oil and Gas Company, USA United.

Amiad also provides treatment solutions for other demanding industrial water applications, such as process water filtration, inlet water filtration and seawater filtration.

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