Atlas Copco CD Heatless Regenerative Desiccant Dryer

Atlas Copco CD heatless desiccant dryer: 3 to 191 CFM, minus 40°F dew point

The CD is the small end of Atlas Copco's adsorption dryer line, sized for one compressor rather than a plant: the CD1.5 at 3 CFM up to the CD90 at 191 CFM, all on 115 volt single phase. It is the dryer to add behind a 2 to 50 HP compressor when a refrigerated dryer cannot get the air dry enough, which usually means air lines that freeze in winter, paint and powder finishing, laser and plasma cutters, dental and lab air, and instrument air. Standard dew point is minus 40°F; a minus 100°F fill is available by quote.

How to size it: ratings are at 100 PSIG and 100°F inlet. Choose the CD with a rating at or above the compressor's delivered CFM, and allow for purge air, which on a heatless dryer is 15 to 20 percent of the rated flow. A 10 HP screw making 40 CFM should run a CD10 (21 CFM) only if the actual tool demand is low; in most cases it wants the CD55 to leave real air for the tools, or the purge saver and dew point dependent switching option to cut purge when demand drops. Maximum working pressure is 232 PSIG, so the CD also suits 175 PSI two stage piston compressors. Each cartridge has an integral afterfilter and a PD prefilter ships with the dryer; install both.

Install downstream of the receiver and, if you have one, downstream of a refrigerated dryer so the desiccant only handles the last few grains of moisture. The unit mounts vertically or horizontally and a wall mount kit is available, which keeps a 20 to 60 CFM unit off the floor. Plumb the prefilter drain to an oil water separator. The inlet and outlet can be swapped to suit the piping run.

For a refrigerated dryer at the same flows see the FX and FD; to compare brands see the Quincy QCMD and the nano desiccant dryers. Browse all desiccant air dryers and Atlas Copco products.

Manufacturer description

The CD+ adsorption dryer is a twin tower heatless regenerative desiccant dryer. The dryer is completely wired and equipped with all interconnecting pipe work and fittings

Working Principle

The general working principle of adsorption dryers is simple. Moist air flows over hygroscopic material (typical materials are silica gel, molecular sieves, activated alumina) and is thereby dried. The exchange of the water vapor in the moist compressed air into the hygroscopic material or “desiccant” to gradually be saturated with adsorbed water. Therefore, the desiccant needs to be regenerated regularly to regain its drying capacity, Adsorption dryers are typically built with two drying vessels for that purpose. Each tower switches the tasks when the other one is completely regenerated. Typical Pressure Dew Point (PDP) that can be achieved is -40C, which makes these dryers, suitable for providing very dry air for more critical applications.
CD is a purge regenerated adsorption dryers. The regeneration process takes place with the help of expanded compressed air and requires approximately 15-20% of the dryers nominal capacity at 7 bar € working pressure.

The Compact Solution

1. High-quality components designed for low pressure drop and increased reliability provide fail-safe operation.
2. Filled with high-performance molecular sieves to allow for various pressure dew points (-40°C/-40°F and -70°C/-100°F). Overfilled cartridges protect against desiccant aging and overflow peaks. Integrated after-filters ensure fast and clean maintenance.
3. Multi-port inlet and outlet provide easy connection to the air system. The dryer can be installed vertically or horizontally.
4. Integrated silencers minimize noise.
5. Full electronic controller with purge saver function. The sophisticated electrical panel is IP65-protected against water and dust.
6. Service and maintenance-friendly
   • Desiccant bags allow for quick replacement without spilling adsorbent material.
   • A spring covers the bags to prevent damage by desiccant moving due to pressure pulsations.
7. Attached filters
   • A durable PD pre-filter prevents oil contamination to increase desiccant lifetime and is included for installation in the air piping.
   • A DDp after-filter protects the airnet from desiccant dust and network contamination and is included for installation in the air piping.
   • To be installed in the air piping.
   • Easy to assemble and maintain.
8. Nozzle purge set
   • Offers flexibility in optimizing regeneration pressure for lowest purge air consumption. Standard is 7 bar; 4 and 10-bar nozzles come as separate parts.
9. Advanced options
   • Pressure dew point sensor required for Dew Point Dependent Switching.
   • Wall mounting kit.

Features and Benefits

Enduring performance

• Non-return valves and purge cavities are built into the polycarbonate cartridges.
• Each desiccant cartridge includes an integrated afterfilter to save space, simplify installation and decrease the risk of leaks.
• The dryer can perform in working pressures up to 16 bar(g)/232 psig and temperatures up to 50°C/122°F.

Energy efficiency and savings

• Low pressure drop across the whole range.
• Purge saver function is included as standard.
• Adjustable purge, available as an option, matches purge air consumption to the actual working conditions.

Easy operation

• The controller shows the dryer/cycle status and automatic fault diagnosis.
• No need to disconnect the dryer from the compressed air network for servicing.
• The inlet and outlet can be reversed. The dryer can be operated remotely.