Industrial Air Dryer Systems for Compressors

In compressed air systems, the presence of water vapor can severely impact the system’s integrity and performance by causing component corrosion, freezing, and other problems. For these reasons, industry professionals integrate air dryers into compressed air systems to remove water vapor from compressed air. While all air dryers have the same function—i.e., removing water vapor—they come in several variations, each of which employs a different air drying agent.

Below we outline the four main types of air compressor dryers available.

Refrigerated Air Compressor Dryers

The most commonly employed type of air dryer is the refrigerated compressed air dryer. Similar to a refrigerator, it relies on a cooling process to perform its function. As the compressed air cools inside of the dryer, the moisture it contains condenses into a liquid, which is then extracted and drained from the system.

Compared to other industrial air dryers for compressors, refrigerated compressed air dryers offer lower setup, operating, and maintenance costs and better resistance to airborne oil particles. While they are suitable for use in a wide range of industrial facilities, they are not appropriate for applications involving sub-freezing temperatures or high dew point capacities.

These air dryers can be categorized into one of two classifications:

• Cycling: Cycling refrigerated air dryers cool compressed air as it enters the system. Once the desired temperature level is achieved, the system turns off. As these air dryers adjust their operation depending on the demand (including in regard to air flow and temperature), they are more energy-efficient than their non-cycling counterparts.
• Non-cycling: Non-cycling refrigerated air dryers continuously circulate refrigerant through the system. This design allows them to respond quickly to changes in the incoming air. Compared to cycling air dryers, they have more consistent dew points.

Regenerative Desiccant Air Compressor Dryers

Desiccant dryers—also referred to as adsorption dryers or regenerative dryers—generally employ the use of desiccant media (e.g., silica gel or activated alumina) in two separate towers to remove moisture from compressed air. The media in one tower absorbs moisture until it is saturated. At this point, the air-drying operation is diverted to the second tower, so the desiccant material in the first tower can dry out for use in future operations.

Compared to other compressed air dryers, desiccant dryers achieve lower dew points, offer moderate operating costs, and (heatless variations) accommodate pneumatic operations for use in remote, mobile, and hazardous environments. They are often used for material processing and mold prevention in pharmaceutical, healthcare, food processing and fabric production to name a few.

These air dryers are available in four main variations:

• Heatless: Heatless regenerative desiccant air dryers rely solely on purge air—without the use of internal or external heaters—to dry the desiccant material.
• Heated: Heated regenerative desiccant air dryers employ internal or external heaters AND purge air to dry the desiccant material.
• Heated Blower Purge: This twin tower desiccant dryer employs a separate heated blower that delivers hot air for drying without using compressed purge air thereby providing a very efficient low dew point drying option.
• Heat of compression: Heat-of-compression air dryers utilize the heat generated during compression to dry the desiccant material. They are available in twin-tower and single-vessel variations. The former operates similarly to other types of twin-tower desiccant air dryers, except regeneration relies on compression-generated heat. The latter employs a rotating desiccant drum contained within a pressure vessel with two distinct air streams. The desiccant dries one stream, and the other stream dries the desiccant.

Deliquescent Air Compressor Dryers

Deliquescent compressed air dryers operate similarly to desiccant compressed air dryers—i.e., rely on specialized chemical media to remove moisture from compressed air. The distinction between them is how the medial removes the moisture; desiccant media adsorbs moistures, while deliquescent media absorbs media. This chemical difference means that once the material in these systems is completely saturated, it must be replaced with new material. With this in mind there is no compressed purge air used to dry desiccant, so it operates more efficiently saving up to 20% in air or energy.

Compared to other types of compressed air dryers, deliquescent dryers require little to no monitoring or maintenance and incur minimal setup costs. These dryers are highly suitable for applications involving no access to electrical power, outdoor environments, or exposure to corrosive, dirty, and hazardous conditions.

Membrane Air Compressor Dryers

Membrane compressed air dryers feature special membranes that allow certain compounds (i.e., water vapor) to pass through faster than other compounds (i.e., air) to facilitate the maintenance of specific concentrations in different areas of the system. As the membrane lowers the water vapor levels at the outlet of the dryer, the dew point is much lower (as low as -40° F).

Compared to other compressed air dryers, membrane dryers offer low installation and operating costs. They are suitable for installation in outdoor and hazardous atmosphere environments, but not appropriate for use with high-capacity systems.

Why Choose Industrial Air Dryers from Airmatic Compressor?

Air dryers play a critical role in air compressor systems. As such, it is essential to choose the right one for a facility’s equipment, regardless of whether it is a component of a small air compressor system or a standalone unit connected to a large air compressor system. Whether a customer requires a refrigerant, desiccant, or membrane dryer, the experts at Airmatic Compressor are here to help.

At Airmatic Compressor, we are New Jersey’s largest distributor of air compressors and vacuum pumps. Equipped with over four decades of industry experience, we have the knowledge and skills needed to help our customers find the right air dryers for their air compressor systems. To find out more about our products and services or discuss your needs with one of our experts, visit our about us page or request a quote today.