What is Activated Alumina Desiccant?
Published On:February 3, 2021 Revised On:March 16, 2023

What is Activated Alumina Desiccant?

A Basic Principle of Drying & Adsorbing by Activated Alumina is that the hydrated Activated Alumina is rapidly dehydrated during activation. It could sop up reversibly after the activation, which is a physical adsorption process. The drying effect of the Activated Alumina is better than any sorbent because it has a stronger absorptivity to the water. Even if under very low frictional pressure and concentration, it still has a much high adsorptive capacity. Therefore, anywhere it is used, we always could get a deep dryness. Under a wider operating scope and dynamics, the Activated Alumina always possesses a much high drying efficiency. It has traits such as a highly adsorbing capacity, a fast adsorbing speed, good stability for heat, steady operating repetition, and no smash when met with a liquid.

Regeneration of Activated Alumina

Activated Alumina

A heat-regenerate method is generally used during a drying application of Activated Alumina, which uses heated nitrogen to blow and sweep. This is because of a strong interaction between water and the Activated Alumina. It isn’t easy to desorb an adsorbed water entirely by the other method. A heating and desorption process includes three heating, washing, and cooling steps: the higher temperature, the absolute for the desorption, and regeneration. The heating and regenerating temperature of the Activated Alumina could be between 180 – 350 centigrade. A temperature in the Activated Alumina tower should be raised to 280 centigrade and stood for 6 hours. A warming speed should be below 50 centigrade per hour.

As a high concentration vapour under a high-temp could have the Activated Alumina structure, the Activated Alumina bed layer must be washed by nitrogen, air, production, gas, and other suitable gas during heating. The washing gas strives to contain non-moisture because a moisture quantity in the washing gas could directly affect a regenerating result.

A regenerated Activated Alumina bed layer must be cooled before an adsorbing process. When washing the bed layer with a cooling gas, the gas also strives to contain non-moisture. The musical direction of the regenerated gas is the same as the direction of the adsorbing circulation. When Activated Alumina is used in a liquid such as propylene, a liquid must be ferreted out of the Activated Alumina bed layer while regenerating. Any dead angle shouldn’t be left in the process. Otherwise, a remained liquid could be reacted or carbonised in the heating process that strongly affects the operating life and efficiency of the adsorbing circulation.