The Impact of Adsorption Dryers

The Influence of Adsorption Dryers on Your Compressed Air Quality

Did you know that compressed air at a temperature of 30 degrees can contain about 30 grams of moisture in vapor form per m3? The moisture can end up in the piping, leading to corrosion. Moisture in compressed air can cause major problems. Therefore, it is important to counteract this moisture. In this blog, we will discuss the adsorption dryer and explain how it works.

What is Adsorption Drying?

An adsorption dryer is often used in compressed air systems. It is important to prevent contamination, bacterial growth, problems, and damage to (pneumatic) machines. This can be done by drying compressed air through adsorption drying. A compressed air compressor draws in ambient air, which contains a lot of moisture and dirt. When the air is compressed, the water vapor turns into liquid form. The air then enters the adsorption dryer and is dried to the desired air class. For each compressed air application, a specific air class is required according to ISO8573-1:2010. An adsorption dryer can provide a class starting from -.3.-. This class indicates a Pressure Dew Point of -20°C. Most adsorption dryers can deliver up to a class of -.1.-. This class indicates a Pressure Dew Point of -70°C.

How Do Adsorption Dryers Work?

An adsorption dryer has at least two columns (beds) that are both filled with hygroscopic material (adsorption beads) that hold moisture. The compressed air is initially passed through one bed, where the water vapor binds to the hygroscopic material, and the air exits the adsorption dryer dry. Once the beads are saturated with moisture, the air is directed through the other bed, and the airflow to the first bed stops. The amount of moisture removed from the air depends on how long the air was in contact with the beads. When the first bed is saturated, it is regenerated using dry compressed air. It can also be heated or heated ambient air can be used to facilitate moisture absorption. One tank dries while the other regenerates, alternately. This is called Pressure Swing Adsorption (PSA).

Where and Why Are Adsorption Dryers Used?

Adsorption dryers are always used where the compressed air quality must be at least -20°C dP. Think of steel compressed air lines and pneumatic tools that are very sensitive to corrosion. Since the adsorption dryer provides dry air, corrosion is prevented. In general, adsorption dryers are used in production processes where a specific compressed air class is required.

In industries such as food and beverage, adsorption dryers are always used because higher compressed air classes are required here. These classes start from -.0.-. according to ISO8573-1: 2010. This class can be read as -20°C dP to -90°C dP. The compressed air used in the food and beverage industry must meet a high class to ensure food safety. This way, mold and bacterial growth are prevented, shelf life is extended, and corrosion in the pipes is avoided. The compressed air must also be FAD safe, and this can only be achieved using an adsorption dryer.

What Should You Consider When Selecting Adsorption Dryers?

When selecting an adsorption dryer, you must consider the desired compressed air class. Compressed air quality is specified in ISO8573-1:2010 and consists of nine classes, with most cases using up to class 5. This involves checking the purity class for particles, moisture, vapor, liquid water, and the total oil present in the compressed air. The moisture and water droplet purity class indicates how much moisture needs to be removed from the compressed air. If you have an adsorption dryer with class 1, this typically means you have the driest compressed air. Read more about ISO8573-11:2010 in this blog.

To choose the right adsorption dryer, it is important to know the required compressed air quality and how dry the air needs to be. It is always advisable to have an expert or specialist review this. You can always reach out to me for a free consultation.

The Difference Between a Refrigeration Dryer and an Adsorption Dryer

A refrigeration dryer and an adsorption dryer can both be used in a compressed air system. However, there are some differences between the two. The advantages of a refrigeration dryer are that it does not consume additional regeneration air, or purge air, while an adsorption dryer, on the other hand, consumes 20% more capacity for purge air. A refrigeration dryer also requires minimal maintenance, whereas an adsorption dryer requires mandatory annual maintenance. A refrigeration dryer can only dry up to a Pressure Dew Point of +3°C, while an adsorption dryer can reach a dew point of at least -70°C. This requires maintenance to prevent issues and extend its lifespan. Another difference is that a refrigeration dryer can remove most moisture, which is known as industrial dry air. In contrast, an adsorption dryer can dry air to higher classes for moisture and water droplets. For further specific insights, please contact me!

When to Use an Adsorption Dryer or a Refrigeration Dryer?

When selecting the right dryer, the required compressed air class and the dew points that need to be reached are considered. It is recommended to use an adsorption dryer when a dew point of -20, -40, or -70 degrees needs to be achieved, corresponding to class 1 to 3. For class 4 to 5, it is advised to use a refrigeration dryer with a dew point of +3°C to +7°C. Sometimes, refrigeration dryers and adsorption dryers are used together to reduce energy costs. The ATT (Antares) 040-340 series from Parker includes this combination in one unit. The Antares series has a flow rate of up to 2040 m3/hr and a dew point range between +5 and -70 degrees.

What Types of Adsorption Dryers Are Available in Our Range?

As a Parker Distributor for Compressed Air & Gas Treatment, we offer all types of adsorption dryers from Parker. We supply both small and large adsorption dryers. The main factors in choosing a dryer are the required flow rate, the dew point to be achieved, and whether a cold or warm regenerated adsorption dryer is needed. The adsorption dryers typically offer three dew point options: -20°C, -40°C, or -70°C.

• The K-MT & KA-MT 1-8 series have a flow rate of up to 86 m3/hr.
• The K-MT & KA-MT 10-95 series have a flow rate of up to 940 m3/hr.
• The KE-MT 250-600 has a flow rate of 6100 m3/hr.
• CDAS, OFAS, and FBP have a flow rate of 300 m3/hr and are suitable for industrial applications in food, beverages, and pharmaceuticals.
• The MX series has a flow rate of up to 300 m3/hr.
• The MXLE series has a flow rate of 2040 m3/hr. With a cascade setup, higher flow rates can be achieved by connecting multiple dryers in sequence.
• The WVM (warm regenerated) adsorption dryer has a flow rate of 14500 m3/hr and is intended for industrial applications. The WVM series offers a 25% energy saving, draws in ambient air, and does not use purge air.

For more information on adsorption dryers, refer to our online catalog from page 30 to page 61.

Free Advice on Adsorption Dryers?

We are happy to assist you in reviewing your specific situation and recommending the right dryer. If you would like more information or advice about adsorption dryers, feel free to contact me at patrizia@interfilter.nl or +31 (0)6 57 42 00 91. Of course, my colleagues are also always available to assist you via the contact details in the pop-up on the right of your screen.