Activated Alumina is comprised of a synthetically-produced aluminum oxide (A12O3) in a smooth spherical form with high-crush strength. It is highly porous and can have a high surface area greater than 300 m2/g. It is an excellent desiccant for liquids and gases, and can achieve dew points from -40°F (-40°C) depending on the operating conditions and the design of the dryer. Activated Alumina will adsorb many molecules to some degree, but will preferentially adsorb the molecules with the highest polarity.
Activated Alumina works as a desiccant through adsorption, so as air passes through the Activated Alumina beads, the water in the air sticks to it and becomes trapped, enabling the air that passes through the activated alumina filter to become dried out. Even if immersed in a liquid, the Activated Alumina will not fall apart or soften.
Activated Alumina can be restored to its original adsorption efficiency by heating the desiccant to any temperature from 350° to 600° F (177° to 316° C). When the Activated Alumina desiccant is heated as described above, the water stored in it is released, which enables the Activated Alumina filters to be reused over and over again.
AGM offers Activated Alumina in three different sizes of beads: 1/8” (2-5 mm), 3/16” (4-8 mm) and 1/4” (5-10 mm). Activated Alumina in a 1/8” (2-5 mm) bead size is most commonly used in regenerative dryers.
Typical applications for activated alumina are used in:
- • compressed air dryers
- • water purification to remove fluoride, arsenic and selenium
- • removal of degradation acids from transformer oils, lubricating oils, and refrigerants
- • natural gas drying
- • liquefied natural gas drying
Activated Alumina is extremely effective for drying gases and is very stable physically and chemically, even in high temperatures and corrosive environments. Activated Alumina is most frequently used for compressed air dryers, because of its cost effectiveness in relation to the other types of desiccant. With its high surface area, high moisture capacity, and high crush strength, Activated Alumina can easily withstand the saturated conditions that are found within an air compressor.