Compressed Air / Gas Drying Units

Our range of compressed air drying units and gas drying units include air dryers, heatless type dryer, internal heat re-activated type dryers, external heat re-activated type generators, refrigerated type generators etc. These drying units are designed to deliver the highest levels of performance at all times.

Compressed air is used in various industries for different applications in pneumatic tools, pneumatic instruments, pneumatic machines and in production processes. The consequences of using wet air are as follows:

• Rust and scale deposits in steel pipes.
• Increases resistance in flow.
• Malfunctioning of process control instruments.
• Corrosion and damage of electromagnetic valves and pneumatic system.
• Peeling and blistering effect on spray painted surface etc.

Thus it will affect the quality of product and lead to excessive maintenance cost.

Ideal Compressed Air System
Air from the compressor has excessive moisture and contaminants. A typical compressed air system removes the damaging impurities to get clean and dry air. When compressed to 7Kg/cm2g the temperature of discharge air reaches around 140^oC. The after cooler and oil separator is installed. After compressor to cool the air, and remove 90% of moisture and oil. When the compressor takes in 100 NM3/hr of ambient air at 40^oC and 50% relative humidity, at 7Kg/cm2g the after cooler condense an average of 30 liters of water in 24 hours.

The outlet air temperature from the after cooler is 40^oC. It contains 8000 ppm moisture. At 45^o C compressed air contains 10,500 ppm, at 50^oC, 13,500 ppm moisture, which is removed by Air Dryer.

Pre Cooler
If compressed air temperature is higher than 40⁰C, it is essential to pre cool. This cooling is achieved in a shell & tube type heat exchanger using cooling water. Using this cooling some moisture condenses out, which helps in keeping the moisture load low on Air dryer and better Dew-point of air.

Dew Point
Dew point is the measure of moisture in Air. It is the temperature where moisture present in the Air, starts condensing. Lower the dew point, more dry in the Air. Air of (-) 40⁰C Dew point means no moisture would condense unless the temperature of the compressed air goes below (-) 40⁰C. For most industrial applications dew point of around (-) 10⁰C is satisfactory. However, as a common industrial practice, most of Air dryers are rated for (-) 40⁰C Dew point. Lower the dew point, higher would be the operating cost.

Oil Filter
Oil present in compressed air is detrimental to the desiccant of air dyer. If the oil is not removed, it gets coated on the desiccant and reduces moisture adsorption capacity. This results in frequent replacement of desiccant. For oil lubricated type compressor, an oil filter before the air dryer is essential. This oil filter has activated carbon, which removes oil from the air completely and enhance the life of desiccant.

It is the simplest type of air dryer among various air drying units with activated alumina / molecular sieves drying agent. It is the cheapest design, which is virtually fully automatic and maintenance free. These heat less type dryers do not require any heating for re-generation and therefore are very simple in design and smooth in operation.

In heat less dryers, two vessels are filled with desiccant, which cycle automatically, producing dry air continuously. In these units, wet air enters the bottom of one vessel and passes upwards through the desiccant bed where the moisture is adsorbed. The dry air comes out from the top.

A small portion of dry air is passed downward through the desiccant bed in the second vessel, which is under re-generation. Then the moisture laden purge air is vented out to atmosphere. The purge loss is around 7.5% of the total air flow.

At preset interval, the vessels changeover automatically and dry air is available continuously, without any surges, The purge air requirement is around 20% if (-)80⁰C dew point is needed from heatless type Air Dryers.

Salient Features

• Fully Automatic
• Eliminates need of costly heaters for regeneration, and also no cooling water requirement
• Low temperature operation reduces corrosion in towers and desiccant lasts longer
• Automatic re-pressurizing equalizes desiccant vessels pressure before changeover. So Desiccant movement is avoided
• Desiccant life is around 5- years.
• Power requirement is Single-Phase, 60 watts only.