Heatless Type|
Heat of Compression Type (HOC) |
Internal Heater Type (IHD)
Blower Heat Regenerated Type (BRD)
|
Split Flow-No Purge Loss Type (SFD)
Refrigerated Type | Custom Made
Airox Nigen has developed Heatless Air Dryer which is a chemical desiccant using dryer, working on adsorption principle. The system consists of twin towers filled with desiccant of appropriate quality and quantity. These dryers use a small proportion of the processed compressed air to reactivate the wet desiccant bed. Although many manufacturers claim to be more efficient than their competitors, no desiccant dryer manufacturer actually makes any desiccant; it is far too complex and expensive. The result is that they all tend to buy the same products from the same source.
A heatless dryer will need between 15-18% of the dried air to be used for reactivation purposes. This is commonly called purge air. One advantage of heatless dryers is that they can be pneumatically controlled; this allows them to be installed into hazardous areas. If you say it quickly 15-18% does not sound much. But it is very expensive. Having gone to the trouble of compressing the air, filtering the air and drying the air, almost 1/5th is blown back through the wet tower on a continual basis to regenerate the desiccant.
The principle of heatless regeneration is simple. When you expand compressed air from 7 bar g to atmospheric pressure, the moisture content inside the air remains the same in real terms. For example, if it contained 1 gram at pressure, it still contains 1 gram once expanded. However, the relative humidity of the air will change dramatically. Instead of 1 cu meter of compressed air containing 1 gram, we now have 7 cu meters of expanded air containing 1 gram. The air has become much drier.
By venting 15-18% of the processed compressed air back through the wet tower at atmospheric pressure, the air is significantly much drier than the desiccant bed it is passing over. The molecules of water vapor jump out of the wet desiccant into the dry air, thereby reactivating the bed. Wet process gas enters a coalescing pre-filter, then pass through the inlet valve assembly and is directed towards chamber-1 where the clean gas passes upward trough the desiccant.
Gas drying takes place by adsorption. Dry gas from chamber-1 outlet then passes through the outlet valve assembly and through the after-filter to the dry gas receiver tank. A Heatless Air Dryer is the simplest form of desiccant type gas or air dryer for achieving a dew point of -40 deg Celsius or better for compressed air systems and other gas and air dryer application. While gas is being dried in chamber-1, the desiccant in chamber-2 which has been humidified in the previous cycle is being simultaneously regenerated.
Chamber-2 is depressurized, in the downward direction and the vent gas is released to atmosphere through a purge valve. A controlled portion of the dry gas is used to flush out the desorbed moisture from chamber-2 desiccant. When the regeneration is complete, the purge valve is closed and chamer-2 is slowly re-pressurized to line pressure for a smooth changeover. A drying period of 5 minutes provides an efficient dew-point of -40 deg. Celsius or better (at atmospheric pressure). In regeneration process approximately 60 seconds are required for re-pressurization.
Process gas heatless desiccant dryers are factory skid-mounted and pre-commissioned. They are fully automatic and require no operator. All operations take place automatically and gas purity remains consistent. Our Heatless air dryers are compact, economical, pre assembled, fully automatic, “Fit and Forget” type of units with very little power consumption of around 100 watts. For detailed offer, please indicate capacity, pressure, and source of compressed air.
• Moisture separator with automatic drain.
• Replaceable cartridge type pre-filter.
• Twin vessel desiccant gas dryer with PLC controlled change-over valves.
• Vent exhaust silencer.
• Replaceable cartridge type after-filter.
• Pressure release safety valve.
• Pressure indicators and transmitters.
• Control panel with electric timer or cam timer or PLC.
• Online dew-point analyzer if required is available as an option.
• Outlet air dew point of -40oC is achieved.
• There is no increase in the effluent gas temperature.
• Since the drier size depends only on flow and pressure, inlet temperature of 10oC to 50oC can be handled by same unit.
• Very low spare parts inventory.
• Desiccant beds can remove oil in its vapor form.
