What is a Desiccant Air Dryer and How Does it Work?
Getting moisture-free air directly from the environment for industrial use is nearly impossible. If excess moisture isn’t removed from the compressed air used in industry, it can impact the quality of the process air and harm moisture-sensitive machinery. This article explores the benefits of using a desiccant air dryer in industrial air-drying processes.
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What Are Desiccants?
Desiccant refers to a substance or material that has the ability to absorb moisture from its surroundings. It is commonly used to reduce humidity or moisture levels in the air, gases, or solids, thereby preventing corrosion, mold, and other undesirable effects associated with high humidity.
Types of Desiccants
Most desiccant materials are stable chemically, but a few are toxic and can only be used under special conditions. The most common types of desiccants include:
- Silica – A commonly used desiccant made from silicon dioxide, known for its high adsorption capacity and versatility.
- Activated charcoal – Known for its porous structure, activated charcoal is used to adsorb moisture and impurities.
- Calcium chloride – An effective desiccant, calcium chloride is often used in the form of moisture-absorbing pellets or bags.
- Calcium sulfate – This desiccant is used to control humidity and is often found in various industries.
- Aluminosilicate minerals (zeolites) – Microporous minerals with a high surface area, zeolites can adsorb water and other molecules.
Desiccants have found applications in both everyday domestic use as well as large-scale industrial applications such as compressed air drying.
What Is a Desiccant Air Dryer?
A desiccant dryer or an adsorption dryer is a piece of industrial equipment that uses desiccant materials to eliminate water from the air channeled through it. A standard desiccant dryer system uses a two-tower setup to ensure a continuous air-drying cycle.
What Is Meant by Regenerative Desiccant Air Dryer?
The term “regenerative” is used to refer to an industrial desiccant air dryer that can renew its desiccant material by reversing the adsorptive process. Typically, regenerative desiccant dryers have paired desiccant-packed towers that permit water absorption and material regeneration to occur simultaneously.
Twin Tower Desiccant Compressed Air Dryers
Twin tower desiccant dryers are essentially dual desiccant systems that constantly switch between absorptive and regenerative modes. Indicators detect the level of water saturation in each tower and automatically switch phases when appropriate.
How Do Desiccant Dryers Work?
This dryer type possesses two towers equally filled with hygroscopic materials. During routine operation, one tower is used to actively eliminate moisture from compressed air channeled through it while the other tower undergoes a reverse process where moisture is actively removed to “regenerate” the desiccant material.
Once the desiccant in the absorptive tower is saturated and the material in the second tower is sufficiently dried, a control unit is used to automatically reverse their functions. With this phase change, the fully saturated desiccant tower then enters a regenerative mode while the freshly regenerated material in the second tower is used to remove the moisture in the supply air feed.
How to Regenerate Desiccant Beads
Regenerating desiccant material is done by eliminating the moisture it has accumulated during a cycle of compressed air drying. There are different ways of regenerating the hygroscopic materials used in air drying systems.
Hot Air Desiccant Regeneration
This method forces a stream of heated air through the water-saturated desiccant tower to eliminate the moisture within it. This drying technique requires a fan, and an electric heater to dry the desiccant.
Desiccant Regeneration Using Dry Compressed Air
Renewing desiccant using a portion of the freshly dried compressed air is energy-efficient and saves operators additional costs on utilities.
Desiccant Drying using Special Drying Systems
This air dryer system can simultaneously regenerate its desiccant and dry compressed at the same time. This air dryer has a rotating drum system where a quarter of the drum is involved in desiccant regeneration while the remaining portions are concurrently drying the compressed air.
Common Applications of Desiccant Air Dryers
In industries using compressed air, desiccant air dryers are widely employed. For instance, the oil and gas industry relies on compressed air for various operations, such as oil recovery, refining, and transportation. The equipment used in these processes is often at risk of damage from moisture.
The use of a desiccant air-drying system prevents the rapid wear and breakdown of moisture-sensitive components in most industries.
Where to Buy Desiccant Air Drying Systems
Not every air-drying system is a perfect fit for your specific needs. Before investing in an air dryer for your industrial process, consult with experts who have in-depth knowledge of air-drying solutions. With decades of experience, NiGen specializes in manufacturing compressed air dryers tailored for various industrial applications.
Discover NiGen’s Industrial Air Dryer Systems
For over 20 years, NiGen has built a strong reputation for offering the best and most affordable solutions for drying compressed air. Our high-quality desiccant dryers, suitable for various industrial processes, are also available for rent. Top of FormBottom of Form
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