Activated Alumina: Best Air Drying Desiccant

Understanding Activated Alumina Adsorbent

One of the most commonly used adsorbents, Activated Alumina is known for its numerous pores and large surface area. Both these features help the adsorbent take in more moisture molecules over a larger area. Another highlight of Activated Alumina as a desiccant is that it can take in all the liquids and gases without undergoing any kind of physical as well as chemical transformation. Activated Alumina functions by the means of a process known as adsorption. This desiccant is mainly used for drying air. The presence of humidity molecules in the air can prove to be quite harmful as it can lead to problems like ice formation, corrosion in the machines. Thus, it becomes highly important to remove moisture molecules from air for the smooth functioning of equipment. also Check our Latest article here:Oxygen Absorbers | Food Storage | O-Buster Suppliers

The functioning of the Activated Alumina adsorbent is very simple. The air, which is meant to be dehumidified, is passed through the Activated Alumina. As it passes through all the moisture present in the air will stick to the Alumina and only the dried air will pass forward. The vapor molecules in the air are trapped in the Activated Alumina desiccant. Thus, with the help of the alumina adsorbent, the air is completely dried.

Activated Alumina in Air drying

Sometimes it becomes important that all the moisture present is removed from the air being circulated. If compressed air having a pressure dew point of around -40 °C / -40 F or lesser is what is needed, then one should opt for a heat less adsorption dryer, which is both energy as well as cost effective. These heats less adsorption dryers carry out their work with the help of desiccant material like Activated Alumina or Molecular Sieve. These two desiccants are best suited to remove all traces of moisture from the compressed air.

The functioning of the heat less adsorption dryer is explained as follows:- The dryer consists of two identical adsorption towers filled with equal amounts of either Activated Alumina or Molecular Sieve. There is no hard-and-fast rule that only one type of desiccant can be used. Either of the two can be used as both are equally effective.

As the drying process begins, the compressed air moves from the bottom to the top of the tower and as it passes through the Activated Alumina desiccant, all the moisture present is readily absorbed. As the moisture intake takes place, the desiccant bed will start to get heavy and eventually become saturated. When the desiccant in the first tower is completely saturated, it automatically shuts down.

The next step is to remove the saturated desiccant from the first tower. The desiccant is purged by passing dry compressed air from the top of the tower to the bottom and for it to come in contact with the ejected moisture molecules.

So while all this is happening in the first tower, what is going on in the second tower, you may ask? During the time period when the desiccant in the first tower is being regenerated, the second tower is functioning as normal. This is in order to ensure that there is a continuous flow of dried air in the system.

While the desiccant bed of one tower will be regenerated, the other tower will be in production in order to guarantee a continuous flow of dried air. The ever flowing stream of dried compressed air is an indication that both the towers filled with Activated Alumina desiccant are functioning smoothly. 

There are many factors influencing how the adsorption dryers perform. These include the temperature of the dryers, their operating pressure as well as flow. If the operating temperatures are raised beyond a certain point, it will drastically affect the production process.