Compressed Air Dryers

A compressed air dryer is a device for removing water vapor from compressed air. A Dryer can remove moisture from compressed air to a certain degree of dryness and this is referred to as pressure dew point. Compressed air dryers are commonly found in a wide range of industrial and commercial facilities.

The solution for compressed air treatment problems in SE Georgia and Florida is Gulf Atlantic Equipment and Hankison International. With products ranging from point-of-use filters and condensate drains to high capacity refrigerated and desiccant dryers, a constant supply of cool, clean, dry compressed air is ensured. Whether for a large manufacturing plant, a hospital or a small business such as an auto repair shop, Gulf Atlantic Equipment has the products and service to suit your needs.

Atmospheric contaminants, including water vapor, are concentrated when air is compressed. The dew point of the compressed air relative to free atmospheric air is therby raised and leads to condensation downstream of the compressor within pipes, tools and equipment as the compressed air cools. Excessive liquid water or vapor in compressed air can cause a variety of problems including freezing air lines, equipment corrosion, and process or product contamination.

Different types of dryers can achieve different dew points and, for the most part, the drier air needs to be, the more expensive it is to dry. (The obvious exception to this is the Atlas Copco MD Series heat of compression dryer that uses the energy of a 100 watt light bulb, yet achieves incredibly low pressure dew points.)

Gulf Atlantic Equipment Company is proud to offer the finest dryers on Earth, properly applied and competitively priced.

• Refrigerated Dryers condense the moisture out of the air and drain it away as liquid. They are limited to about 35° F because the water would freeze if it got any colder.

• Desiccant Dryers adsorb the moisture in the compressed air and remove it while still suspended as vapor. They are typically applied at about -40° F, but can get to -100 and below.

• Deliquescent dryers deliver a dew point suppression that fluctuates with air temperature but is typically 20F below the compressed air temperature.

• Membrane Dryers use permeability to separate the moisture from the air and can also achieve low dew points.

The selection is made on personal preference, the dryness required, and cost, which should include operating and electrical or utility costs.

The Atlas Copco FX Series of refrigerated air dryers offers better efficiency, lower pressure drops, higher reliability, and environmentally friendly designs at an economical price.

Refrigerated Dryer

Refrigeration dryers employ two heat exchangers, one for air-to-air and one for air to refrigeration. However, there is also a single TRISAB heat exchanger that combines both functions. The compressors used in this type of dryer are usually of the hermetic type and the most common gas used is R-134a. The goal of having two heat exchangers is that the cold outgoing air cools down the hot incoming air and reduces the size of compressor required. At the same time the increase in the temperature of outgoing air prevents re-condensation.

As of the year 2000, most manufacturers started producing energy saving dryers that do not make use of a hot-gas by pass. These dryers can save up to 40% in total energy and can consume only 10% of the max power when idle. They employ digital control and sometimes variable speed compressors.

Some manufacturers are marketing compressors with built in refrigeration dryers, but these have had a mixed acceptance in the market.

Commonly a coalesing prefilter is installed immediately upstream of a refrigerated dryer to remove lubricating oil and other contaminants that have the potential to foul the dryer's heat exchangers.
Deliquescent Dryer

A deliquescent dryer typically consists of a pressure vessel filled with a hygroscopic media that absorbs water vapor. The media gradually dissolves—or deliquesces—to form a solution at the base of the pressure vessel. The liquid must be regularly drained from the vessel and new media must be added. The media is usually in tablet or briquette form.

Deliquescent dryers have no moving parts and don't require electrical power for operation. Common applications therefore often involve remote, hazardous, or mobile worksites. Deliquescent dryers are used for removing water vapor from compressed air, natural gas, and waste gases such as landfill gas and digester gas.

The performance of a deliquescent dryer, as measured by outlet dew point, is highly dependent on the temperature of the air or gas being processed, with cooler temperatures resulting in better performance.
Desiccant Dryer

The term "desiccant dryer" refers to a broad class of dryers. Other terms commonly used are regenerative dryer and twin tower dryer, and to a lesser extent adsorption dryer.

The compressed air is passed through a pressure vessel filled with an adsorbent media such as activated alumina, silica gel, molecular sieve or other desiccant material. The desiccant can bring the dewpoint of the water vapor in the air down to -40 degrees Celsius or below. This means that the air will not condense (deposition) water until it is cooled to -40 degrees Celsius. In practice two cylinders with desiccant are used; one is drying the air, while the other vessel is being regenerated. The switching of the vessels and the regeneration sequence is typically done automatically via solenoid operated valves.

The regeneration of the desiccant vessel can be during three different methods:

* Heatless "pressure-swing" drying which uses part of the dry compressed air coming from the other vessel to dry the desiccant in the vessel being generated at lower pressure.
* Heated dryer, this can use a hot air blower, so there is no loss of compressed air.
* Heat of compression. This can only be used with an oilfree compressor.

Membrane dryer

Membrane dryer refers to a dehumidication membrane that removes water vapor from compressed air. It is used in pneumatic components, air bearings, air spindles, medical equipment, air guns and pneumatic brakes for vehicles & trains.

Usage

* Drying air for use in commercial or industrial processes that demand dry air:
o Telecomm industry (pressurizes its underground cables to repel moisture and avoid shorts)
o Painting
o Pneumatic tools
o Pneumatic control systems
o Feed air for Zeolite type Oxygen and Nitrogen generators

* Truck and Train Air brake systems.

Industrial Air.com

E-mail: sales@industrial-air.com

Home | About Us | Compressors | Air Dryers | Blowers | Nitrogen | Resources