Desiccant Air Dryers

Posted on: October 17, 2022

Desiccant air dryers

If your business or project relies on dry, clean compressed air, then you need to invest in some type of air dryer for your air compressor system. Desiccant air dryers are a popular option because they’re efficient, simple to use and are available in multiple types for various industries.

What Is a Desiccant Air Dryer?

When air compressors intake air to compress, that air gets warmer as compression levels reach 100 pounds per square inch (psi) or higher. As the stream of compressed air cools, it creates vapor and moisture. Desiccant air dryers are one method of combating this moisture by adsorbing and reversing the cycle for applications requiring very dry or sterile air.

Desiccant dryers rely on desiccants, a dry material — typically available as a powder or small beads or pellets — covered in surface pores that attract and remove water through a process called physisorption.

Why Desiccant Air Dryer Systems Are Important

An air dryer is an essential part of an air compressor setup, especially in industries with strictly regulated requirements. A desiccant system or similar is necessary for:

  • Compressor maintenance: Air dryers keep excess moisture from collecting in an air compressor, which can lead to rust, corrosion and premature wear and tear on individual components. Poorly maintained compressors are less efficient, taking longer to get the job done while consuming more energy than typical.
  • Preventing air contamination: Many industries that rely on compressed air also rely on that air being as pure as possible. Bacteria grow and thrive in wet, warm environments, and internal rust particles can infuse into the output air stream.
  • Ensuring dry applications: Some compressed air applications can’t afford any level of moisture in the air stream, especially if that amount is unpredictable or contaminated. For example, painters using compressed air for paint application could damage or ruin a project by disrupting the balance of the moisture-to-paint ratio.

How Does a Desiccant Air Dryer System Work?

As wet air flows over a desiccant, moisture is adsorbed, drying the air for output. Desiccant adsorption works through either physisorption or chemisorption, which binds the desiccant molecules to the water and creates new chemical bonds.

The desiccant sits inside the air dryer in either a screen, bed, try or similar filtration system. As the input air flows into the dryer, saturating the desiccant material as it moves, resulting in dry air and wet desiccant materials. Once the air exits, desiccant air dryers for air compressors regenerate the used desiccant materials for reuse. Some desiccant materials can be reused multiple times before needing a replacement.

Specific internal processes vary depending on if the system uses heatless or heated methods:

Heatless

Heatless desiccant dryers store desiccants in a drying tower and a separate regenerating tower that removes adsorbed moisture from the desiccant material through compressed air expansion.

The dryer moves the air from the drying tower filled with desiccant to the second tower, where it’s regenerated through the heat it generated throughout adsorption. The two-tower system lets the dryer cycle air continuously for a reliable flow, and the exit air has pressure dew points ranging from 40 degrees to minus 100 degrees Fahrenheit.

Many heatless air dryers from Quincy Compressor use a special Q-Sorb formula for high adsorption levels and lower operating costs.

Heated

Heated desiccant dryers use heat naturally generated from the compressor to purge vapor and air before expelling it, regenerating the desiccant material for reuse. Other heated models have a heater in their circuit system.

Specific results and methods vary between the type of heat it uses. For example, heat-of-compression air dryers reuse the heat naturally generated by oil-free air compressors, which makes the air reach extremely high temperatures. As it flows through an aftercooler, it starts to cool and lose some moisture before entering the drying tower. The end result is a dew point of about minus 40 degrees Fahrenheit.

Applications for Desiccant Dryers

You’ll find desiccant dryers in nearly every industry requiring ultra-dry or high-quality compressed air, including the following:

  • Medical: Dry, sterile compressed air is critical for many medical applications, including in hospitals, emergency rooms, intensive care units and dental offices. Air for medical use has to be reliable and clean, especially when used for ventilation systems that deliver oxygen to high-risk patients with critical conditions, like those undergoing surgery or patients that can’t breathe on their own.
  • Commercial artistry: Commercial air applications, such as vehicle paint detailing and woodworking, play a large part in what a final product looks like, which is why operators need air free from bacteria and rust contaminants.
  • Food and beverage: Food and beverage manufacturing and distribution centers need sterile, dry air to keep all items fresh and within safe temperature levels for sale and consumption.
  • Manufacturing: Manufacturing facilities use dry compressed air for machine equipment and maintenance, and any unwanted moisture could damage high-performing systems and wear components down.
  • Pharmaceutical: Pharmaceutical developers work with highly sensitive materials, and even minuscule inconsistencies or contaminants can render entire batches unsafe for use.
  • Creative projects: Many crafters and artists need dry, clean air to complete their projects, especially those with high levels of detail or made with delicate materials.
  • Agriculture: Residential and commercial farms often use compressed air to spray crops for cleaning or processing, and excess moisture or bacterial contaminants could cause additional harm or render crops unusable.

Even operations that don’t work with strict production standards or have an explicit need for sterile or ultra-dry air can benefit from an air drying system for their compressor. The more control you have over the air you use for projects, the better the final product will be.

They’re also a highly effective way to maintain your air compressor and help prevent premature wear and tear or corroded components. Air compressors can be a big investment, and if your air compressor system plays a critical part in your operations, proactive maintenance should be your top priority.

Quincy Compressor Has the Solution for Your Air Needs

Quincy Compressor has been a trusted leader in the air compressor industry for decades, and our technicians are available 24/7 to help you find the right compressor or compressor accessory for your business or project. In addition to a range of air compressor types and sizes, we also have four main types of desiccant air dryers:

  • QHD-series heatless dryers: An affordable investment with low operating costs and a microprocessor control that supports 15% purge rates for wet air.
  • QHP-series heated dryers: Ideal for heavy-duty applications or operations seeking lower energy consumption than heatless models. Pair your heated air dryer with the Quincy MicroBurst Regeneration (MBR) system to save even more money by halving purge requirements, ultimately giving you a return on investment (ROI) in as few as five months.
  • QBP-series blow-purge dryers: Our most energy-efficient air dryer with 1.75% purge rates and low maintenance and ongoing operating costs. Blow-purge dryers are NEMA-4 compliant.
  • QMOD and QMD dryers: Modular heatless air drying systems suitable for light-duty use.

Learn more about Quincy air compressors and air compressor products online, or find an authorized sales and service representative near you.