Activated Alumina for use in Compressed air dryers including (not limited to) Atlas Copco CD, BD, BAP+ & MED+ Dryers.

Please contact us with specific model for quantity requirements. Price here is per kg.

4A Molecular Sieve is a sodium-based aluminosilicate desiccant designed for effective moisture removal from liquids and gases, while also adsorbing small molecules such as carbon dioxide, oxygen, and nitrogen. With a nominal pore size of 4 angstroms, it provides a versatile balance between drying efficiency and molecular adsorption, making it one of the most widely used grades in industrial drying and purification.

The material offers consistent adsorption speed, good contamination resistance, and reliable regeneration performance, supporting long service life across repeated cycles. Supplied in 4×8 mesh, 4A Molecular Sieve is well suited to dynamic systems where low pressure drop and stable flow characteristics are required, as well as static drying applications.

Key Features

• Effective moisture removal from liquid and gas streams

• Adsorbs small molecules including CO₂, O₂, and N₂

• Consistent adsorption performance and strong cyclic stability

• Good resistance to contamination and long operational life

• Supplied in 4×8 mesh for low pressure drop in dynamic systems

Typical Applications

• Refrigerant drying

• Moisture removal in PU plastics and paint systems

• Natural gas drying

• Drying of cracked gas streams

• Static drying of insulating glass units, air-filled or gas-filled

• Dehydration of highly polar compounds, such as methanol and ethanol

• Dehydration of unsaturated hydrocarbons (e.g. ethylene, propylene, butadiene)

• Drying of compressed air and industrial gases

Protecting your systems and processes

Desiccant air dryers provide the ultimate in energy efficiency and supply extremely low dew points

For a broad range of industrial applications

Complete range of desiccant air dryers for a broad variety of industries and applications with dew points down to -70°C / -100° F

Protect your production

Our patented Elektronikon control and monitoring system takes continuous care of your desiccant air dryers to ensure optimal productivity and efficiency at your site

How does a desiccant air dryer work?

Twin tower desiccant air dryer working principle

Adsorption dryers are used when the compressed air application requires a pressure dew point below 0°. The regenerative desiccant dryers consist of two pressure vessels. Both vessels are filled with desiccant. One vessel is removing moisture from the compressed air.

Wet air passes directly through the desiccant bed which adsorbs the moisture. When this vessel is saturated with moisture the valves will switch and lead the air to the other standby vessel. During adsorption in the other vessel, the first vessel will be regenerated. It's a cyclic process.

The desiccant medium has a finite capacity for adsorbing moisture before it must be dried out, or regenerated. To do this, the tower containing saturated desiccant medium is depressurized and the accumulated water is driven off.
How this happens depends on the type of dryer.

• Heatless dryers use only compressed air as a purge
• Blower purge dryers use a combination of air from an external blower, heat, and minimal compressed air
• Blower zero purge dryers use a combination of air from an external blower, heat, and zero compressed air
• Heat of compression dryers use the heat of the compression
• Heated purge dryers use heat and small amount of compressed air

Types of desiccants

Depending on the technology and dew point requirement, there is always the best choice of desiccant, sometimes a combination of multiple layers of desiccants used in our designs. In this way, we will ensure required PDP levels and maximized lifetime for desiccant.

Activated Alumina grade D​

Premium quality desiccant, long lifetime, few dust forming

High performance silicagel​

Premium quality desiccant​, long lifetime​, few dust forming​

Cerades™: a groundbreaking desiccant

Some Atlas Copco innovations change everything. Cerades™, the first ever solid desiccant, has revolutionized adsorption dryer design, efficiency and performance. And that makes all the difference for you as you enjoy better air quality, lower energy and service costs, and health and environmental benefits.

Water resistant silica gel​

15% extra capacity to cope with aging​, resistance against free water​, limited dust forming​