Difference between revisions of "Desiccant Dryers"

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[[Category:Drying]]{{Knoppen}}
[[Category:Drying]]{{Knoppen}}
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[[File:Desiccant_Dryers.jpg|thumb|right|Desiccant Dryers]]
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[[File:Desiccant_Dryer_Principle.jpg|thumb|right|Desiccant Dryer Principle]]
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The '''Desiccant Dryers''' are used for drying air in [[Storage Tanks]] or pneumatic systems and are beneficial in the drying of hygroscopic (water-absorbing) resins. These [[Dryers]] remove water from the air by passing it through a desiccant that absorbs moisture. The term "desiccant dryer" refers to a broad class of [[dryers]]. Other terms commonly used are [[Regenerative Desiccant Dryers]] and [[Twin Tower Dryers]], and to a lesser extent [[Absorption Dryers]].
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The compressed air is passed through a [[Pressure Vessels|pressure vessel]] filled with an absorbent media such as activated alumina, silica gel, molecular sieve or other desiccant material. The desiccant can bring the dew point of the water vapor in the air down to −40 °C (−40 °F) or below. This means that the air will not condense (deposition) water until it is cooled to −40 °C (−40 °F). 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.
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The '''Desiccant Dryers''' are used for drying air in storage tanks or pneumatic systems and are beneficial in the drying of hygroscopic (water-absorbing) resins. These dryers remove water from the air by passing it through a desiccant that absorbs moisture.
 
[[Heatless Dryers]], which uses part of the dry compressed air coming from the other vessel to dry the desiccant in the vessel being regenerated at lower pressure. [[Heated Dryers]], which uses a hot air blower, so there is no loss of compressed air. Heat of compression, which can only be used with an oil free compressor.
 


==Features==
==Features==
Desiccant dryers consist mainly of two cylinders containing desiccant, connected by a valve system.==Operation==When the desiccant in the first cylinder is saturated, the air flow can be switched to the cylinder containing the dried desiccant.
Desiccant dryers consist mainly of two cylinders containing desiccant, connected by a valve system.
 
 
==Operation==
When the desiccant in the first cylinder is saturated, the air flow can be switched to the cylinder containing the dried desiccant.
 


==Dessicant Types==
==Dessicant Types==
Common desiccants are silica gel (an oxide of silica), alumina (aluminum oxide) and calcium sulfate (the anhydrous form of gypsum).
Common desiccants are silica gel (an oxide of silica), alumina (aluminum oxide) and calcium sulfate (the anhydrous form of gypsum).


==Types of Dryers==
==Types of Dryers==
While manual desiccant dryers exist, many dryers are regenerative desiccant dryers, as noted in the Plant Services magazine article, "The Economics of Operating Regenerative Desiccant Dryers," by Noel Corral and Andrew Sheaffer.
While manual desiccant dryers exist, many dryers are [[Regenerative Desiccant Dryers]].
 


==Most Expensive==
==Most Expensive==
Heatless regenerative desiccant dryers run a portion of dried compressed air through the previously utilized cylinder to extract moisture from its desiccant.
Heatless regenerative desiccant dryers run a portion of dried compressed air through the previously utilized cylinder to extract moisture from its desiccant.


==Least Expensive==
==Least Expensive==
Heated purge regenerative desiccant air dryers use less air than the heatless variety in addition to heat, which helps the air carry away more water as it passes through the saturated desiccant.==Best Compromise==Heated blower purge regenerative desiccant air dryers use air from outside the dryer that is heated and sent through the water-saturated desiccant for drying.
Heated purge regenerative desiccant air dryers use less air than the heatless variety in addition to heat, which helps the air carry away more water as it passes through the saturated desiccant.
 
 
==Best Compromise==
Heated blower purge regenerative desiccant air dryers use air from outside the dryer that is heated and sent through the water-saturated desiccant for drying.
 


==Classification==
==Classification==
There are different types of regenerative desiccant compressed air dryers. These are:
There are different types of regenerative desiccant compressed air dryers. These are:
* Small Heatless Desiccant Air Dryers
* Small Heatless Desiccant Air Dryers
* Large Heatless Desiccant Air Dryers
* Large Heatless Desiccant Air Dryers
* Compact Heatless Desiccant Air Dryers
* Compact Heatless Desiccant Air Dryers
* Mini Heatless Desiccant Air Dryers
* Mini Heatless Desiccant Air Dryers
* DMD Desiccant Modular Dryer
* DHL Desiccant Heatless Dryer
* DEX Desiccant Externally Heated Dryer
* DBP Desiccant Regenerative Blower Purge Dryer
==Small Heatless Desiccant Air Dryers==
Using Pressure Swing Adsorption (PSA) technology, the Twin Tower Engineering regenerative air dryers are designed to maximize the efficiency of the drying process. Ultra-Dry compressed air dew points of -40°F to better than -100°F can be achieved.
==Large Heatless Desiccant Air Dryers==
Engineered for long service life and superior protection of your air-operated equipment and processes. THL series heatless regenerative desiccant compressed air dryers deliver the peace of mind of high quality, value and fast delivery.
==Compact Heatless Desiccant Air Dryers==
Economical and compact, these heatless desiccant compressed air dryers provide low dew points to -100°F ADP(atmospheric dew point). This proven "no-frills" design uses Pressure Swing Adsorption (PSA) technology and will provide years of trouble-free service.
==Mini Heatless Desiccant Air Dryers==
Ultra-small desiccant compressed air dryers can be used for low-flow applications or with fractional horsepower air compressors. These units are heatless regenerative desiccant air dryers designed to produce low dew points. Extremely small footprint allows for packaging inside equipment cabinets or at point-of-use.
==DMD Desiccant Modular Dryer==
The Sullair DMD series is a lightweight modular desiccant dryer that offers unsurpassed installation flexibility. This lightweight modular dryer design brings a whole new concept in compressed air technology offering total installation flexibility to meet your specific needs. A small amount of the dried compressed air is used to regenerate the saturated desiccant bed by expanding air from line pressure to atmospheric pressure, removing the moisture absorbed by the desiccant material. Protection is built-in. Extruded aluminum housings that surround the dryers are fully protected from corrosion.
==DHL Desiccant Heatless Dryer==
The dual tower design of the DHL series dryers allows for continuous absorption of water from compressed air by using a desiccant bed. Drying is accomplished by passing wet compressed air through the desiccant bed of one tower where moisture is absorbed. Regeneration of the desiccant is accomplished without the use of heat. The wet bed is dried by diverting a small amount of dry air from the outlet at near atmospheric pressure. The purge flow rate is adjustable to suit the desired dew point. The dry air flows in a counter direction through the wet bed, sweeping all the water vapor previously absorbed by the desiccant.


==DEX Desiccant Externally Heated Dryer==
The dual tower design of the DEX dryers allows for continuous absorption of water from compressed air by using a desiccant. Drying is accomplished by passing wet compressed air through the desiccant bed of one of the towers where moisture is absorbed. Regeneration of the desiccant is accomplished with the use of a low watt density heater. The heated air has a greater affinity to absorb moisture. When passed through the regenerating tower at near ambient pressure, the heated air flows in a counter direction through the wet bed, removing moisture previously absorbed by the desiccant.


==DBP Desiccant Regenerative Blower Purge Dryer==
==Video==
The dual tower design of the DBP, blower purge dryer, allows for continuous absorption of water from compressed air by using a desiccant. Drying is accomplished by passing wet compressed air through the desiccant bed of one of the towers where moisture is absorbed. Regeneration of the desiccant is accomplished using a blower to pass ambient air through a low watt density heater because heated air has a greater affinity to absorb moisture. When passed through the regenerating tower at near ambient pressure, the heated air flows through the wet bed, removing water vapor previously absorbed by the desiccant
<youtube>h3SdBj8tE7o</youtube>

Latest revision as of 05:00, 17 February 2013

Desiccant Dryers
Desiccant Dryer Principle

The Desiccant Dryers are used for drying air in Storage Tanks or pneumatic systems and are beneficial in the drying of hygroscopic (water-absorbing) resins. These Dryers remove water from the air by passing it through a desiccant that absorbs moisture. The term "desiccant dryer" refers to a broad class of dryers. Other terms commonly used are Regenerative Desiccant Dryers and Twin Tower Dryers, and to a lesser extent Absorption Dryers.


The compressed air is passed through a pressure vessel filled with an absorbent media such as activated alumina, silica gel, molecular sieve or other desiccant material. The desiccant can bring the dew point of the water vapor in the air down to −40 °C (−40 °F) or below. This means that the air will not condense (deposition) water until it is cooled to −40 °C (−40 °F). 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 Dryers, which uses part of the dry compressed air coming from the other vessel to dry the desiccant in the vessel being regenerated at lower pressure. Heated Dryers, which uses a hot air blower, so there is no loss of compressed air. Heat of compression, which can only be used with an oil free compressor.


Features

Desiccant dryers consist mainly of two cylinders containing desiccant, connected by a valve system.


Operation

When the desiccant in the first cylinder is saturated, the air flow can be switched to the cylinder containing the dried desiccant.


Dessicant Types

Common desiccants are silica gel (an oxide of silica), alumina (aluminum oxide) and calcium sulfate (the anhydrous form of gypsum).


Types of Dryers

While manual desiccant dryers exist, many dryers are Regenerative Desiccant Dryers.


Most Expensive

Heatless regenerative desiccant dryers run a portion of dried compressed air through the previously utilized cylinder to extract moisture from its desiccant.


Least Expensive

Heated purge regenerative desiccant air dryers use less air than the heatless variety in addition to heat, which helps the air carry away more water as it passes through the saturated desiccant.


Best Compromise

Heated blower purge regenerative desiccant air dryers use air from outside the dryer that is heated and sent through the water-saturated desiccant for drying.


Classification

There are different types of regenerative desiccant compressed air dryers. These are:

  • Small Heatless Desiccant Air Dryers
  • Large Heatless Desiccant Air Dryers
  • Compact Heatless Desiccant Air Dryers
  • Mini Heatless Desiccant Air Dryers


Video

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