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Desiccant air dryer technology explained

Desiccant air dryer technology explained

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Before we look in more depth at the specific technology behind desiccant air dryers, it’s helpful to understand what a dryer does and why it’s such an integral part of your air compressor’s system.


Why do I need an air dryer at all?

All ambient air on this planet contains water, and as we know, water spells disaster for your compressed air system.

Water, if left untreated, can block and freeze supply lines, seize up parts with corrosion and rust, and give bacteria free rein to build up. All negatively impacting the life cycle of your equipment and tools, reducing the efficiency of your systems and worse, ruining your final product.

Our article ‘Compressed Air Dryer – why you need one‘ tells you more.


How an air dryer works – a short explainer

Imagine a wet sponge – squeeze it, and the water comes out.

In the same way, when we ‘squeeze’ or compress air, water comes out. This water then mixes with the oil, dust and other pollutants in your system to form a condensate. An air dryer should be an invaluable element of your air compressor configuration, working to remove the condensate during your processes.

Operating at any given temperature under a prevailing pressure dictates the point when moisture starts to form in your system, this point is called a pressure dew point (PDP). The PDP is a critical determining factor as to which type of air treatment you need.

Make no mistake; your process always governs your air dryer choice.


How do desiccant dryers work?

Specific highly-specialised industrial sectors need a premium quality of dried air to operate successfully; pharmaceuticals, food production, electronics and others, require compressed air dried in strict compliance with ISO Class 1 and above.

In broad terms, there are two types of desiccant air dryers:


Heat is used in the processing of dry air to remove the water vapour from the adsorbent not in use at that point.


Water vapour and condensate are purged from the air in a regenerative process that uses the dry air generated by the dryer. This process reduces the dependence on an external service, e.g. electricity or gas.

All desiccant air dryer variants dry compressed air using an adsorbent material such as activated charcoal, silica, calcium chloride, activated alumina or calcium sulphate.

The compressed air is passed across the adsorbent bed, which draws any condensate away, leaving clean and dry air to move to the next operational stage. Adsorbents don’t last forever and will need to be dried out and regenerated for further use. The most popular desiccant air dryers are regenerative and can house this whole process in one unit for a continuous supply of dry compressed air.

At ACB North, we recommend CompAir’s Compressor Discharge Temperature (CDT) Hybrid dryers. Able to switch between 3oC to -40oC PDP, they offer you high quality compressed air with low energy expenditure.


ACB North – for all your compressed air needs

Choosing the right air dryer for your needs takes experience and technical understanding. Making the right choice will secure long-term efficiency and optimal performance for your entire compressed air system. With nearly a decade of knowledge and expertise in compressed air, blowers, vacuum pumps and downstream applications, ACB North are one of the UK’s foremost specialists in the field.

Why not contact us to discuss your requirements? Call: 0114 398 4488

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