Published: 17/02/2025
How Does A Desiccant Air Dryer Work?
Air dryers are similar to dehumidifiers, but they work differently. Rather than chill air, they rely on desiccant materials to absorb moisture from the compressed air.
This article outlines the desiccant air dryer working principle, its benefits, and why they can be essential for your compressed air needs.
What is a desiccant air dryer?
If a substance is desiccant, it means it has the ability to absorb moisture from its surroundings. The most common types of desiccants include: silica gel, activated charcoal, and calcium sulfate.
So, what is a desiccant air dryer? A desiccant dryer system features desiccant materials to remove moisture from the compressed air that travels through it.
You may hear of regenerative dryers, which refer to dryers which automatically renew their desiccant material. While one of the chambers is drying air, the other is being regenerated.
How does a desiccant air dryer work?
Desiccant air dryers feature two towers which both contain desiccant materials. Compressed air flows through one tower, where the desiccant removes the moisture from the air. While this occurs, the second tower regenerates the desiccant so it is ready to be used again.
Learn more in our article, Adsorption Air Dryer Working Principle.
How is the desiccant regenerated?
The tower produces a ‘reverse’ process. By reducing pressure in the tower and flowing dried air through the desiccant bed, accumulated moisture is removed. How this happens depends on the type of air dryer:
Heatless dryer – Uses compressed air to purge the desiccant of moisture.
Blower purge dryer – Uses a combination of minimal compressed air, air from an external blower, and heat.
Why is a desiccant air dryer for an air compressor important?
If compressed air features moisture in the form of water vapour, it can cause serious maintenance problems. The cost of fixing them is not worth risking.
It can also lead to an increased chance of the compressor leaking and a shorter service life due to corrosion caused by the moisture wearing away the pipework.
Air dryers help protect compressed air systems and their functionality. They maintain the quality of the machine, as well as the product of compressed air.
In industries that require high-quality, clean air, desiccant air dryers ensure that the compressed air produced is free of unwanted moisture. They are commonly used in food and beverage, pharmaceutical, chemical, automotive, and electronics industries.
Opting for a desiccant air dryer ultimately ensures the reliability and lifespan of your compressed air systems; maintaining the quality and minimising excess costs.
Benefits of an air compressor desiccant dryer
- Improved product quality: Drying the compressed air produces a cleaner, higher quality product.
- Extends equipment lifespan: Reduces the chance of maintenance issues and corrosion by removing the water vapour which would cause these problems.
- Reduces energy costs: Dried air takes less energy to compress, which is cost and energy efficient.
- Flexible and customisable: Desiccant air dryers are suited to a wide range of environments. The dew points can be altered depending on the process.
Desiccant air dryer maintenance: A checklist
- Check the filters and pre-filters. If the desiccant materials become contaminated with oil, they must be replaced. This is expensive and time consuming, so ensuring the filter is acceptable and functional can prevent this.
- Check the dust filters. You may need to change the filter cartridge.
- Check the valves. Valves are essential in the desiccant drying operation. If the pressure drops throughout drying, this may indicate a valve leak or faulty valves. You can lose the compressed air and risk improper drying.
- Inspect the desiccant materials. It is recommended to periodically sample the desiccant. Look out for oil contamination, a change in colour and amount/size.
- Check temperature controls on heated dryers. Ensure that it is operating at a safe level without heat fluctuation.
- Service the blower on blower purge dryers. Clean and replace if necessary.
Desiccant Dryers from Air Supply Ltd
Air Supply offers a range of high-quality air dryers, including adsorption air dryers and refrigerant air dryers, at competitive prices! Our team can help ensure your compressed air is dry and free from moisture to keep your machines working efficiently and effectively.
Our site offers one of the UK’s largest stocks of used air equipment, including used air dryers. This is a great option if you’re on a limited budget or wish to try a dryer for your business.
Air Supply also offers comprehensive maintenance, servicing, and repair services. So, if your dryer or compressor has any issues or is not performing as it should, you can rely on our expert technicians to get it up and running again.
If you’re looking for a desiccant air dryer for your compressed air system today, get in touch with us to explore our range of products and services. Our team will be happy to help!