Being the fourth utility of a production facility (the other three being electricity, water and gas) compressed air is a very important resource that should be carefully treated in any manufacturing plant. It should be carefully examined in a periodical manner. The moisture present in the air should be removed and also the contaminants should be eliminated. This will result in the efficient working of the whole system. Improved performance and reduced operational costs are two major perks of having efficient air and gas drying systems. 

Air drying is one of the most significant processes carried out in most large industries. In this technique, the moisture from coatings and surfaces are removed by using hot, dry or forced air. Moisture present in the air can affect colour, coatings etc., and also lead to damage and corrosion. But air-drying is employed to prevent all those problems. 

Significance of compressed air and gas drying

Regular atmospheric air and compressed air all contain some amount of water vapour. This water vapour will cause problems in future because of an increase in water concentration in the system. Therefore, to prevent problems in the future, wet air must be controlled. Drying equipment can be used for the same purpose. 

There is moisture present in the irregular atmospheric air that will have moisture content. When the air or gas crosses the saturation point, this vapour will condense and reach the liquid state. This process happens at a certain temperature and this temperature is known as the dew point. 

• Moisture leads to damages and problems

When the compressed air employed in the manufacturing plant contains moisture, it will damage various valves, pneumatic air systems, air motors, different passages etc. They will cause damages, wear and tear, impact lubrication, corrosion, causes the valves and passages to be plugged and clogged and also affects the overall functioning of the system. Further, the moisture harms the adherence, colour and finish of paint etc. Hence, they- lead to malfunctioning, false readings in the instruments, faulty operations, and even cause the total system to shut down. 

Compressed air and gas drying becomes necessary to obtain perfectly finished products, for the smooth flow of uninterrupted production, improved performance of the whole system and reduced operating costs. 

• Clean and dry air, as well as gas, is necessary for various applications

Air is required in most manufacturing facilities or plants. Most of these plants need dry and clean compressed air for the smooth flow of their operations. Water molecules, dirt or any other contaminants will be deposited inside the pieces of equipment that can even lead to a drop in the pressure of the system. This drop indicates low efficiency in the overall performance of the system. 

• Instrument air used in transmitters, converters, gauges etc., need to be dry

In these pieces of equipment, dry and moisture-free air is needed, as even a little amount of moisture or water vapour can produce significant issues. This may plug the air passages and block them. Further, they can lead to instrument damage. Pneumatic thermostats that are used in the air conditioning and heating cycles of buildings is another instrument that needs dry air.

These types of instruments used in sewage treatment units, manufacturing plants, textile manufacturing units, petrochemical plants are all examples of facilities that need dry air for their smooth flow and efficient operation.

• Valves, as well as cylinders, need moisture free air for their smooth functioning

The slime or sludge that is formed by the dirt and contaminants or oil in the air causes blockages in valves and acts as drags in the cylinders. This causes damages and results in frequent maintenance. There will be a lag in operations, this slowdown of operations will gradually lead to the shutting down of the system. The efficiency will be very low and there will be an increase in costs too.

These are the main reasons why compressed air and gas need drying. Air-gas drying can be achieved through various techniques. Use of air dryers is one popular technique used nowadays and among them, use of desiccant air dryers is the one with most demand as it employs a heatless method. 

The regenerative desiccant air dryers use a desiccant. Activated alumina balls are used mainly in these systems nowadays. These desiccants absorb all moisture content from the air. They have the maximum water adsorption capacity than other adsorbents including silica gel and molecular sieves. Activated alumina balls are exceptional adsorbents of water vapour and moisture. They are highly porous non-toxic substances with high surface area. Sorbead India is one of the most reliable suppliers of high-quality activated alumina balls in India. They provide activated alumina balls of different sizes and types for different types of air dryers. 

Air compression involves making the molecules come closer, and thus force them to fit into a smaller space. This process involves an increase in temperature and is known as the heat of compression. In any air compressor or compression air dryer, this same process is involved and thus results in a lot of heat emission. It is dangerous to leave the heat emitted unattended because it can easily overheat the compressor and can result in an explosion.

Activated alumina balls as the drying medium in a heatless compression air dryer is the best choice to avoid this overheating of the compressor. Let’s look at the heatless compressed air dryer.

Heatless compressed Air dryer

By using activated alumina for the air dryers, we can devise the heatless compressed air desiccant dryer. A dual-chambered arrangement filled with desiccants is aligned to adsorb the water molecules from compressed air. The final output would be hot dry air. The heat of adsorption is retained by the desiccant balls and is prevented from being accumulated at the chamber outlet. This heat is further used for regeneration in the subsequent cycle to nullify the heat accumulation. Effective heat retention, a dense medium of high volumetric heat capacity can be introduced at the end of the adsorption chamber.

But this process consumes a portion of the dry air output from a compressed air dryer. The amount of this consumption can be reduced by the below methods:

• To the end of the desiccant chamber, a very small quantity of heat is introduced
• A low wattage dryer installed at end of the desorption chamber
• Vent the exhaust to vacuum

There are majorly two types of desiccant air dryers which are pressure swing compressed air dryers and externally heated compressed air dryers. The pressure swing regenerative dryers and the high-pressure swing dryers are efficient in reducing the accumulated heat from the entire system. These regenerative dryers make use of the adsorption heat energy retention concept to maintain the heat of compression within limits.

Air drying desiccant balls

The best air dryer desiccant beads in use are activated alumina. It is very important to keep compressed air free of moisture because moist compressed air can cause various damages to the compressor. The valves, motors, and insulations can be affected, the final product can be altered, rusting and corrosion, damage to pipes, total blockage of the system are some examples of the adverse effects of moisture content in the compressed air. So, it is very important to maintain the PDP of a compressor system as low as -40 degrees centigrade.

Regeneration dryers that involve activated alumina balls as adsorbents have doubtlessly proven to be highly efficient and effective. Activated alumina uses the concept of adsorption to trap water molecules that come in contact with the desiccant surface. With no chemical or thermal reactions involved, the use of desiccant air dryer beads is of low operating and maintenance cost. Activated alumina balls are non-toxic, colorless, tasteless, and insoluble, and have high thermal and mechanical strength.

The ease of regeneration of activated alumina balls is a highly recommendable feature. Activated alumina balls in the desorption chamber of the dryer are triggered to action as they saturate with the moisture content from the compressed air. It does not require any additional systems involved and in the context of heatless air compressor dryers, this regeneration phase helps to reduce the heat retained during the adsorption.

Sorbead India is one of the leading manufacturer of activated alumina balls over the years. The quality of desiccant balls, a wide range of quantities available, and easy access to products has helped us remain your trusted partner in all kinds of desiccant requirements. Our heatless compressor air dryer desiccant balls have proven to be highly efficient.

Activated alumina is one of the high performing desiccants among its counterparts. It is used for the purification of various liquids and gases. Been available in various grade, activated alumina balls have a huge surface area that can go above 200 sqm/gm. 

AD101 is the finest grade of activated alumina balls as it has a surface area of around 415sqm/gm. It is made of aluminium oxide and ranges from 1 - 3 mm (2mm), 2 - 5 mm (3.2mm), 5 - 8 mm (6.2mm), etc. 

Features of AD101 grade alumina:

• Resistant to thermal shocks
• Larger adsorption capacity
• Doesn’t shrink, swell or soften
• Higher porosity
• Low bulk density
• Can be used in high pressure
• Has very low attrition loss

Activated alumina balls specifications and parameters (AD101) are as below:

Application of AD101 grade alumina balls

Being an excellent performing adsorbent, AD101 grade alumina finds its application in compressed air dryers, air separation plants and heatless air dryers. One of the major applications is the fluoride removal by activated alumina. Fluoride levels in water if crosses a level can prove dangerous and lead to fluorosis.

By letting water through these powerful desiccants, the fluoride content from water is adsorbed that reducing the levels from 5ppm to less than 1ppm.

Other applications of AD101 grade alumina balls are removal of HCL from contaminated gas flow, Catalyst Bed Support, and Drying of Feed air to N2 – O2 Cryogenic plan,

Sorbead India is one of the prime activated alumina suppliers and manufacturers who deliver high-quality products to their clients across the globe. Contact for more details