Will your upcoming project require an air dryer? Do you have a large ongoing project that involves using air dryers on a frequent basis? If so, you don’t want to just dive into the project with the first air dryer you see. Instead, spend a little bit of time learning and educating yourself about the different types of air dryers out there.
There are many different models and varieties of air dryers for you to choose from. Since every situation is different and calls for a slightly different touch, one size certainly does not fit all when it comes to air dryers. To find the style that is the most fitting and functional for your project, you’ll need to first learn about all the different types.
Each style brings a slightly different set of pros and cons to bear on your project. By examining these, you can better determine which is the right fit for your needs, then act on that decision accordingly.
To help you decide which air dryer might be right for you and your needs, we’ve put together this quick guide to different types of air dryers. We hope that by reading this, you’ll have a much better picture of which air dryer will work best for you.
Different Types of Air Dryers
All air dryers perform roughly the same function — they work to remove any water vapor from compressed air. However, there are many different types of compressed air dryers, and each works in a slightly different way. Here are six of some of the many types of air dryers you can choose between as you select the correct air dryer for your project.
1. Desiccant Air Dryers
Desiccant air dryers are constructed with a dual tower design. When the compressed air enters the dryer, it flows through the online drying tower. Most of this now dry air is sent to downstream equipment and processes. A portion of the dried air is pealed off and put through the offline or regenerating tower. Depending on the type of desiccant dryer, heat may be added to increase the regeneration efficiency of the regenerating air flow. The towers will periodically switch so that the previously online tower can be regenerated. The towers are filled with an absorbent substance known as a desiccant.
Depending on the exact style you purchase, this desiccant material could be activated alumina, silica gel, molecular sieve or some combination thereof. The primary differences between the desiccants other than the cost is the adsorptive capacity and durability. Activated alumina is the most common material used due to its relatively low cost and its durability when exposed to liquid water.
Whichever desiccant material the dryer uses, the air moves into the tower, is dried by this material and then is pushed back out of the machine. These types of dryers are excellent in situations where the air is at or below freezing temperatures.
You can also choose between heated and heatless desiccant dryers. Heatless desiccant dryers work by using the air they’ve just dried to dry out the desiccant material, while heated desiccant dryers produce and apply heat to remove water vapor from the desiccant material that’s not currently being used.
2. Refrigerated Air Dryers
As you might expect based on their name, refrigerated dryers work similarly to home refrigerators. Compressed air is pulled into the machine, which then cools this air. As the temperature of the air drops, the moisture in the air condenses and becomes liquid. Once the moisture is condensed, it collects into a separator that fills up and will eventually need to be drained out. These dryers are equipped with automatic drains to facilitate this process.
It’s important to realize that refrigerated air dryers work in a way that leaves a little bit of water vapor in the air, instead of removing 100 percent of the moisture. So, these types of air dryers aren’t recommended for applications that are water-sensitive.
3. Membrane Dryers
This type of dryer uses a semi-permeable membrane hollow fiber that allows water to migrate across the wall of the fiber and be expelled out of the purge ports. The resultant dry air continues through to the end of the hollow fibers and out to your downstream processes. As with desiccant dryers a small amount of the dry compressed air is used to remove the moisture that has permeated across the membrane surface. This purge air vents to atmosphere in a continuous process.
These membrane dryers are especially convenient in highly remote settings that may not have ready access to resources like electricity. They’re also good in situations with a risk of explosion, extremely low temperatures and applications that must maintain a constant dew point.
With no moving parts membrane air dryers offer an economical and reliable option for compressed air drying.
4. Deliquescent Dryers
A deliquescent dryer is one of the simplest air dryers you can choose. In these machines, the dense, humid air passes into the machine and over a bed of deliquescent tablets. These tablets work similarly to many of the solutions we’ve looked at — they absorb the moisture straight from the air as it passes over them.
This process causes the tablets to dissolve, meaning they will have to be replaced every so often. The moisture that has been pulled from the air then drains out into the designated drain area, and the newly dried air flows freely back out into the open air.
These types of dryers are popular because they’re electricity-free and incredibly low-maintenance. They’re commonly used as landfill gas dryers.
How to Find the Right Air Dryer for Your Project
Based on this list alone, you can easily see there is no shortage of air dryer options out there. But of course, that can be just the problem sometimes. When there are so many choices, how do you know which is the right one?
Here are six tips to help you navigate your way through all the possible choices so you can find the perfect air dryer for your project.
A. Don’t Overestimate Your Needs
In some cases, the air doesn’t need to be dried to excess. In situations like these, partially drying the air will work just as well. If this describes your intended application, realize that you don’t need to buy the largest, fanciest and most heavy-duty machine available. Often, the less intense product will work just as well for what you need.
Over-drying the air and lowering the humidity point far past what is workable is wasteful. You will likely end up spending more money for a machine that is far more than what you need, and you’ll also end up using far more energy than necessary.
B. Don’t Underestimate Your Needs
On the other side of the equation, it’s important not to underestimate your needs either. If you require completely dry air, then it’s worth investing in the more heavy-duty equipment. Air that is too wet can result in damage to your project, expensive maintenance work and time lost while the problems are fixed.
If you truly need the more intense options, don’t hesitate to buy them. It will be worth it.
C. Be Aware of the Ambient Temperature
Think about the space where your air dryer will be working. What will the ambient temperature be like? Is the ambient temperature going to be lower than the temperature of the compressed air coming out of the dryer? If so, you may run into problems with condensation as the air comes out of the dryer.
D. Decide Whether Your Project Can Tolerate Some Water Vapor
Air dryers all have different levels of effectiveness. Some remove almost every single ounce of water vapor from the air, while others leave a little bit. To decide which air dryer is best for your project, you’ll need to decide if your setting can handle a little bit of water vapor in the air or not.
If it can handle some water vapor, a refrigerated air dryer might be appropriate. If not, you will be better off choosing a more robust type, such as a membrane dryer.
E. Know Your Required Dew Point
When you begin doing your research to decide which air dryer you’ll choose, it’s important to take note of the required dew point for your project. Depending on the dew point, different air dryers will be appropriate.
For example, if you require a dew point from 32 to -40 degrees Fahrenheit, a membrane dryer will get the job done correctly. If, on the other hand, your dew point is going to be lower than -40 degrees Fahrenheit, you would be better served by a desiccant dryer.
F. Research Your Industry
Where are you going to be using your air dryer? Because these machines are so versatile and can be used in so many different industries, it’s helpful to know where you’ll be using it first. A few of the industries that regularly use air dryers are manufacturing, pharmaceuticals, nuclear and more.
To get a better idea of which air dryer might be the best for you and your needs, research air dryers throughout the rest of the industry. Which types are other companies like yours using? What seems to be working well for them, and what hasn’t worked so well? You’ll be able to get a fairly good idea from a small amount of research.
Why Choosing the Right Air Dryer Is Important
It might be easy to wonder why any of this matters. If all air dryers perform the same essential function, then why is it important to choose a specific one? Won’t any dryer get the job done?
Yes and no. Any air dryer will most likely remove the water vapor from your compressed air, but there may be side effects that will differ depending on your project. Choosing an incorrect dryer could lead to equipment failure, which will, in turn, lead to potentially expensive repairs. You also might lose time and fall behind schedule on your project.
You can avoid these types of delays and expenses by taking the time to learn about air dryers and how to choose the one that best fits your project’s needs.
Now that you’ve spent some time learning about the various types of air dryers out there, it’s time to start shopping — and there’s no better place to do that than Fluid Aire Dynamics.
With our extensive variety of different air dryers, we’ve got the solution for you no matter your specific needs. We also provide service to compressed air and gas systems, so we can always help you out if something goes wrong in your system.
If you know you need an air dryer for your upcoming project, it’s best to start your search now. To learn more about our products at Fluid Aire Dynamics and how we can help you, request additional information on our website. We look forward to hearing from you.
