Plasma Datis Supplies high quality hybrid dryers for various industries.
Desiccant dryers are commonly used to bring pressure dewpoint well below freezing temperature (usually – 40 C˚) in order to avoid moisture from precipitation in the compressed air system and production equipment.
Usually the need for dry air is seasonal and a refrigerated dryer is perfectly capable of producing air with quality which is needed for most time of the year.
But where humidity and temperature is not suitable for operation of desiccant dryers or refrigerated dryers, a combination of both are used to achieve higher quality of dry air with even lower operating costs.
In a hybrid dryer system, compressed air that has been through a compressor’s aftercooler (usually about 38 C˚) enters the refrigerated dryer and passes through the primary side of the air-to-air heat exchanger where its temperature is reduced down to 21 C˚. This reduction in temperature condenses a large amount of the water vapor and also some oil vapor is condensed in air-to-air heat exchanger as well.
In the next stage the mixture of 21 C˚ saturated compressed air, liquid water enters air-to-refrigerant heat exchanger where the temperature is further reduced down to about 3 C˚, condensing more water vapor to liquid and more oil vapor to aerosols.
Then the mixture of 3 C˚ saturated compressed air, liquid water and oil aerosols enters the refrigerated dryer’s separator where the liquid water and newly formed oil droplets are moved from the compressed air stream. The separator element also captures solid particles about 3 micron and larger.
The cold saturated air goes through and coalescing filter further reducing oil aerosol concentration to 0.01 PPMw. Particles with size of 0.01 micron and larger are separated in this stage.
The cold, saturated, oil-free and particle free compressed air is then passed through a bed heated activated alumina desiccant where its dew point is reduced to – 40 C˚.
After passing through desiccant, the air stream which is cold, dry and free of oil, passes through a one micron particulate filter that captures and desiccant fines swept out of the desiccant bed by the compressed air stream.
At the final stage the cold, dry, oil and particle free air passes through the secondary side of air-to-air heat exchanger. At this stage the dew point is locked and outgoing compressed air is warmed up to - 8 C˚ and incoming air is cooled.
In summer time when lower dew point is not necessary, the desiccant dryer and it’s after filter may be easily switched off. At this setting, only refrigerated dryer is operated but the air will still flow through the moisture separator and coalescing filter and back through the air-to-air heat exchanger.
In summer, when the desiccant dryer is not operating, energy consumption of the system is significantly reduced due to pressure drop across the clean air treatment system where the desiccant dryer is by-passed.
Hybrid dryers have a dewpoint between + 4 to – 40 C˚, they can remove solid particles down to 0.01 micron and oil aerosols about 0.01 PPMw/w.
Hybrid dryers consumes %48 less power than blower purge dryers, %54 less than heat purge dryers and %64 less than heatless dryers. They also have a very lower maintenance cost compared to other dryers.
In heated dryers desiccant is replaced every 2 years, in heatless dryers it is replaced every 3 – 5 years and in hybrid dryers desiccant is replaced every 5 – 7 years.
The fact that desiccant in hybrid systems lasts longer and replacement intervals is much greater is because of several reasons.
First, desiccant is not used all year long. Second, less thermal cycling, results in less use of desiccant during operation of hybrid systems. Third, magnitude of thermal cycling is reduced to about 94 C˚ compared to temperature change of about 150 C˚ in other dryers. Forth, hybrid systems have controlled and slower depressurization of desiccant tank in preparation for regeneration. It is depressurized within several minutes and slowly instead of seconds in heatless desiccant dryers, reducing the velocity of pressurized air and causes much less breakdown to desiccant in less frequent intervals than other dryers.
Another major reason for lower cost of desiccant is, because the amount of desiccant used is hybrid dryers is nearly half of the heatless dryers and almost one sixth of heated dryers per year.
Due to longer valve cycles in hybrid dryers, nearly half of the heated dryers and nearly %99 less valve actuation cycles than heatless dryers, valve life in them is much longer than other dryers.
Hybrid dryers, because of mentioned reasons, are more flexible, reliable and cost efficient in many ways comparing with other dryers.
Plasma Datis supplies an innovative compressed air filter and dryer system that uses %50 less energy. We offer a hybrid dryer system which offers highest efficiency in running and maintenance as well as performance. It adapts automatically to changing demands in both compressed air and pressure dew point.
The volume of flow rate of hybrid dryers we supply ranges from 1.200 m3/h up to 9.000 m3/h. Higher capacities available on request.
