Maintaining a low pressure dew point (PDP) is important for compressed air operations. To achieve desirable conditions, you'll likely need an aftercooler and air compressor dryers.
This article focuses on the latter and explains the differences between two main types, refrigerated and desiccant (adsorption).
Before comparing these dryers, it's worth diving into the impacts of high PDP or water vapor / moisture. If conditions are too humid, you run the risk of corrosion, contaminated air, and other quality control concerns.
In addition to atmospheric moisture, water vapor is created inside air compressors. This moisture is formed from rapid temperature changes by the air compression process.
Not only do dryers maintain a desirable PDP, they also remove undesirable particles. The right type of equipment for you depends on your application, environment, and air quality requirements.
It's also worth pointing out that PDP is not the same as the atmospheric dew point, and only refers to compressed air water content. Also, using a filter isn't effective in removing water vapor.
With this information in mind, read on below to better understand what makes the most sense for your situation.
As you might imagine, a refrigerated dryer cools air. This process condenses water before it is separated and occurs in a closed system. After moisture is removed, the air is then reheated to avoid pipe condensation.
Capable of achieving a PDP between +2˚C to +10˚C, refrigerated dryers are suitable for most standard pneumatic applications. They have a low freezing limit at the point of condensed water and can remove high quantities of vapor.
These machines typically have the lowest cost of investment and come in a range of capacities and working pressures. In addition, modern equipment is designed with PDP monitoring. With this information, you'll remain updated on dew point levels.
You'll also find features like intelligent drain discharge on some models. Using electronic sensors, this component removes condensate without wasting any compressed air. There's also optional filter support and features to reduce installation costs.
With refrigerated dryers, setup and maintenance is fairly simple and straightforward. We've designed easy to use, long-lasting machines to minimize operational costs as much as possible.
Explore our range of fridge dryers to find a solution for your air compressor size and industrial application.
If you require a very low PDP and extremely clean air, you'll want a desiccant / adsorption dryer. With these machines, hygroscopic material is used to separate water vapor from condensed air. The most common types of desiccant are silica gel, molecular sieves, and activated alumina.
Through moisture removal, these dryers can achieve a PDP of -40 °C or lower. Producing extremely dry air, desiccant equipment is suitable for chemical, food, and pharmaceutical applications.
To maintain consistent operations, desiccant material must be regenerated. The most common way this is handled is through two towers within the equipment. One vessel is used for drying air, while the other refills the adsorption material.
Helping manage your workflow, you'll find features like a digital control, electronic dew point management system, and optional PDP sensor on new machines. These machines also tend to be fairly quiet and come with on board silencers.
When using any oil-injected equipment, it's important to carefully dispose of condensate. Essentially, when water is removed from an air compressor, it usually contains tiny contaminants such as oil. Not following guidelines could lead to fines and negatively impact the environment.
You'll want to ensure an oil/water separator is installed with a foul drain. Condensate should never be drained to a basic plastic container or the floor. Luckily, a proper setup is generally easy to install.
Make sure to check your local regulations regarding condensate removal, usually found at recycling centers.
We hope this overview on refrigerated and desiccant dryers provides enough information for you to make the right decision. If you still need help choosing the right size and solution for your application, feel free to get in touch today. Our team of experts will guide you through the purchasing process.