Have you ever wondered how industries ensure that their products are free from moisture? One of the answers is through the use of desiccant dryers. These machines remove moisture from the air using a process called adsorption.
But how exactly does it work? In this blog, we’ll dive into the inner workings of desiccant dryers & explore their applications in various industries.
Desiccant dryers rely on hygroscopic materials known as adsorbents to extract moisture from air at high pressure. At any given time, one tower may be drying the compressed air online while the other stands aside or undergoes regeneration cycles.
Function of Desiccant Dryers
Desiccant dryers are engineered to function by passing air through a material called desiccant, which absorbs any hygroscopic materials that absorb water vapour, typically silica gel, activated alumina, or molecular sieves that have the capacity to hold and absorb vapour even at very cold temperatures until saturated; then these materials can either be regenerated or replaced by new desiccants for reuse in another cycle. Desiccant dryers are most frequently employed when applications require low dew points, such as when drying resins used in plastic manufacturing applications.
Refrigerated dryers are very energy efficient, consuming significantly less electricity to run than their contemporaries. Their desiccant lasts twice as long, reducing maintenance costs significantly.
Costs of Desiccant Dryers
When purchasing a desiccant dryer, both the initial purchase and operating costs should be taken into consideration. While initial costs tend to be less than those for refrigerated dryers, their energy usage for regeneration air heating can quickly add up over time.
Be mindful of replacement desiccant costs as well. Most hygroscopic desiccant dryers feature chemical indicators that change colour when they need replacing or regeneration; this allows for an extremely accurate schedule and prevents costly downtime.
This type of dryer features a massive tower of desiccant capable of handling the full flow rate from an air compressor for 16–20 hours before needing regeneration, usually only taking 4–8 hours! Regeneration takes place via a small side-channel blower.
There is one key downside to this type of dryer: oil from your compressor can contaminate the desiccant and make it unable to do its job, rendering it ineffective. Therefore, a filtration system must be in place that captures any oil as air leaves the compressor; without this measure in place, your desiccant would soon become covered in oil, which prevents it from absorbing and holding moisture.
Desiccant dryers contain hygroscopic material that absorbs moisture vapour as compressed air passes through them, eliminating moisture that would otherwise lead to corrosion, mould growth, or other quality control issues in your compressed air system. Once saturated, desiccant must be regenerated or replaced, an expensive process required by industry standards. Adding one could prevent costly air quality issues and help extend the longevity of your air compressor!
Regenerative desiccant dryers offer many advantages when it comes to energy consumption, particularly due to their energy-efficient adsorption process and reduced maintenance needs that further cut energy usage.
With electricity costs rising steadily, more companies are searching for ways to lower their energy bills and their carbon footprint. Desiccant dryers have quickly become one of the go-to products among industrial air systems as a cost-cutting measure and environmental solution.
Regenerative desiccant air dryers use less energy than other types of air dryers because they don’t rely on heat sources to operate. Instead, this type of dryer uses the adsorption process to extract moisture from compressed air instead of using other methods like evaporative or pressure swing methods to do the same task.
Regenerative desiccant dryers have the added advantage of producing ultra-dry compressed air at minimal energy consumption, making them essential to production processes in factories and plants to prevent product contamination, increase manufacturing efficiencies, and ensure high standards of quality for finished goods.
Regenerative desiccant dryers can become even more energy efficient with the addition of a dew point sensor, reducing energy waste while saving significant money in terms of energy savings. Newer twin-turbine regenerative desiccant dryers equipped with Elektronikon controls may provide this feature.
Moisture build-up in an air compressor system can wreak havoc, leading to corrosion of pipes and cylinders, freezing of outdoor air lines (indoor), premature failure of pneumatic instrumentation tools, and adversely impacting end product quality.oisture can also contribute to higher maintenance costs and a shorter equipment lifespan. To remove excess moisture, installing either a heatless compressed air dryer or a regenerative desiccant dryer would help.
These air dryers employ hygroscopic materials that have an affinity for water absorption. Adsorption works like dew on grass or condensation on cold beverages during a warm day: when air passes over this material, it absorbs any droplets that come its way. Eventually, however, it must be purified to restore its ability to adsorb, which explains why such air dryers tend to be more costly compared to refrigerated models.
These types of air dryers provide many advantages over refrigerated units, including lower maintenance and energy costs as they don’t rely on refrigerants to achieve low pressure dew point levels. Furthermore, these units can feature dual tower designs to alternately absorb and purge air as needed.
Once one tower becomes saturated with moisture, it is switched over to another tower in order to keep the system operational while also helping the air reach the desired pressure dew point. Heated desiccant dryers may further reduce purge air requirements compared to heatless desiccant dryers.
Desiccant dryer adsorption cycles must be controlled with great care in order to provide maximum reliability, with air flowing slowly through its towers and not too quickly; otherwise, too much air velocity could cause fluidization or rub between itself, disintegrating desiccants into disarray, resulting in contamination entering downstream filters as well as wear on valves and towers themselves. A high-efficiency dryer that achieves the desired pressure dew point without overpressurizing the system could help mitigate this potential hazard.
Air contains water vapour that, when introduced into compressed air systems, can lead to corrosion of pipes and equipment, freezing of air lines (for outdoor applications), pneumatic instrument and tool failure, decreased system efficiency, and decreased efficiency overall. quality compressed air dryer should be utilised in order to combat such issues and ensure system efficiency remains at its peak.
Desiccant dryers are the go-to device for drying compressed air. Consisting of two pressure vessels with towers filled with hygroscopic material like activated alumina, silica gel or molecular sieve hygroscopic materials attract water vapor in compressed air via absorption; when one tower becomes saturated with it then another tower’s air is diverted back towards drying the first tank via valve opening; this allows up to 20% more dried compressed air as purge air from one tower while leaving its other tower ready to receive another stream of compressed air for drying the first tank thereby saving one tank full tower’s capacity for later use as purge air purge air recovery while leaving another tower available ready for another air stream from dry compression!
These dryers offer two options for regenerating desiccant: by using hot air or by using dried compressed air. Installing and operating a separate system to provide hot compressed air through a desiccant regenerative desiccant can be expensive; alternatively, some models of desiccant dryers feature valves that enable users to replace it with dry compressed air instead, saving on energy costs as well as environmental impacts by not disposing of used desiccant in landfills.
Deliquescent dryers operate similarly to twin tower regenerative desiccant dryers, but with one major distinction: instead of becoming saturated with moisture as it evaporates, deliquescent desiccant is consumed as moisture condenses and settles at the bottom of its vessel. This type of air dryer can be more cost-effective and suitable for high ambient temperatures compared to traditional air dryers, making it suitable for industrial applications.