In this blog post, we will try to give a brief summary of what should be considered when choosing a filtration system for your cooling tower requirements.
The importance of cooling water filtration systems for protecting equipment and complying with environmental regulations.
Various types of filtration methods: side – full stream, and make-up water filtration.
Different filtration technologies including centrifugal separators, sand filters, automatic screen and disc filters, and more.
Key factors while choosing a filtration system: location, flow rate, filtration degree, operation and capital costs.
All Industrial manufacturing facilities mostly require cooling water to cool down chillers, heat exchangers, products and other devices, and this equipment needs to be protected against contaminants found in the cooling water.
In addition, environmental regulations force the manufacturers return the utilized cooling water to its source in a non-pollutant state.
How about the cooling water filtration benefits?
- Improved heat transfer rates in water cooling system for a longer period
- Reduced water consumption
- Improved chemical effectiveness
- Reduced chemical consumption
- Reduced maintenance and energy costs
- Increased equipment lifetime
The above-mentioned regulations require that cooling water be chemically treated and monitored on a regular basis, specifically for corrosion, scaling, suspended solids and biological fouling.
Corrosion, scaling and biological fouling can be controlled by routine water treatment, but the suspended solids can be more challenging as they can reach the system in various ways, such as production contaminants, pipe corrosion and variations in the raw water composition.
On the other hand, airborne particles are also an issue and, in some cases, can lead to high dirt loads. If left untreated, suspended solids can cause poor energy transfer and obstructions and have an adverse effect on the efficiency of the chemical treatment.
Filtration plays an important role in protecting cooling systems and is divided into 3 categories: side stream water filtration, full stream water filtration and make-up water filtration.
Side stream filtration systems constantly filter a portion of water to remove suspended solids and organics, reducing the likelihood of fouling, scaling, and microbiological growth. Side stream filters may be installed parallel to the collection basin or between the pump and heat exchanger.
Full stream filtration; a filtration unit is installed on the discharge side of the pump, after the cooling tower, and continuously filters all of the recirculating water in the system.
On the other hand, Water is lost during the cooling process and make-up filtration process is used to replenish the water reservoir used for cooling. There are four reasons for this water loss:
- Naturally occurring evaporation
- Blowdown/Bleeding: to reduce conductivity and particle concentration
Cooling Water Filtration Technologies
Making an informed decision about which filtration technology is the right one for your system is essential. It is important to understand the general application requirements, including filtration degrees, as well as reviewing the advantages / disadvantages and costs of each technology.
- Hydrocyclones
Hydrocyclones, also known as Centrifugal separators, use centrifugal forces to separate heavy solids larger than 70 micron from water. They are frequently used together with a filtration system that can remove finer particles such as bag and cartridge filters, but centrifugal separators do not have capability to stop organic particles.
- Media Filters
Sand/media filters route the cooling water to the media bed. There are various types of filter beds, such as, sand, crushed glass, basalt and more. As the water passes through the bed, the particles get trapped and the filtered water then goes to the bottom of the tank to be discharged through the outlet. Although their filtration efficiency is not bad, the need for more space for installation is the biggest handicap.
- Automatic Screen Filters
Automatic screen filters use multiple screens which trap the suspended solids in the cooling water as it passes through them. Filtered water then flows through the filter outlet. The gradual dirt buildup (cake) on the inner screen’s surface begins the cleaning process. Very low footprint requirements and very low amount of water consumed in backwashing. They provide down to 10 micron automatic filtration precision.
- Polymeric Disc Filters
Disc filters are made up of series of flat grooved discs that are stacked together under pressure. As the unfiltered water flows through the discs, trapping the particles. As more particles are trapped, the filter’s pressure differential increases, beginning the cleaning process. While providing down to 20 micron filtration sensitivity, they offer an economical solution due to their polymeric structure, especially where seawater is used as cooling water.
Enora’s cooling water filtration and technologies help maintain good water quality, improve heat transfer efficiency, decrease opex and are ideally suited to help cope with the challenges associated with the following cooling water applications:
- Spray nozzle filters for nozzle protection
- Side stream industrial water filters for cooling towers
- Full stream cooling systems
- Upstream filtration – heat exchangers protection
- Condenser and chiller loop protection
- Cooling tower makeup
With a comprehensive product line and various filtration technologies – screen, disc, centrifugal separators, cartridge and bag filters, drum filters, media and high-efficiency media – Enora offers customized solutions for the harshest environments, varying water conditions and demanding technical requirements.
You can read more about how our filtration solutions about cooling water filtration filter were implemented in our case studies.