A compressed air dryer dehumidifies air after it leaves a compressor. This is necessary as compressed air contains a lot of moisture and humidity. Left untreated, this air can lead to microbial contamination, corrosion, blocked or frozen valves, cylinders, air motors and tools. The consequences can be significant and costly, ranging from premature production tool failures to production shutdowns and product recalls. A quality compressed air dryer eliminates these risks.

Why does compressed air contain moisture?

Can you avoid moisture in compressed air? In a word – no. The atmosphere contains humidity, in some climates or seasons more than others. When this ambient air is compressed, its temperature increases and its moisture content becomes more concentrated. When it leaves the compressor, the hot compressed air has typically reached 100% relative humidity. This means that moisture content in compressed air cannot be avoided. But it can be removed – with the help of a compressed air dryer.

Who uses air dryers?

Textile Industry?Applications

Air treatment is necessary in almost all compressed air applications. From food manufacturing, to beer brewing, to building electronics, dry compressed air is a must to prevent product and equipment damage. Food and beverage packaging and manufacturing companies use compressed air dryers to prevent their actuators and assembly machinery from rusting. They also eliminate the moisture in the lines that stops clean compressed air from flowing. Dryers are also used in textiles to keep fabrics free of moisture. Many electronics manufacturers need very dry air to ensure that humidity will not transfer over to computers, cell phones, televisions, etc.

Compressed air dryer types

There are different types of compressed air dryers, each with their own working principle and benefits. The most common types of dryers are refrigerated air dryers and adsorption dryers.

Refrigerated air dryers

A refrigerated air dryer relies on a refrigeration system to cool compressed air to approximately 3-4°C/40°F.

As a result, the moisture in the air condenses and can be drained. They are the right solution if you operate in temperatures lower than 40°C/104°F and if your goal is mainly condensation prevention.

Refrigerated dryers come in cycling and non-cycling variants.

It is this energy efficiency and low investment cost that make refrigerated dryers a popular choice. In addition, they offer a reliable performance. Their ease of use and simple maintenance are also strong benefits.

Adsorption dryers

An adsorption dryer dries air by pushing it through a tower filled with desiccant or hygroscopic material. This material adsorbs the moisture in the air, leaving only dry air to exit the dryer. Because the desiccant gets saturated, adsorption dryers consist of two towers. While air is being dried in one tower, the other tower is being regenerated after use. This process prepares the desiccant for a new drying cycle.

Adsorption dryers can reach pressure dew points as low as -70°C/-94°F.

That makes them the ideal solution for applications that require very dry air. They also prevent air system ice formation in very cold climates.

As with all compressed air dryers, energy efficiency and thus operational costs are a key consideration. That is why it is important to take into account the regeneration technology of a dryer. It can make a significant difference in your operational costs. Heatless dryers use expanded compressed air (and thus some of the dryer’s capacity) for regeneration. Heated purge dryers heat up the expanded purge air to limit this purge flow. Blower purge dryers use ambient (not compressed) air and an electric heater. Their zero purge variants also eliminate purge loss during cooling.

Of course, the desiccant material itself also determines efficiency.

Article Source：Pneumatech