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Difference between revisions of "Compressed Air Dryers"
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==Refrigerated | ==Refrigerated Dryer== | ||
Refrigeration dryers employ two heat exchangers, one for air-to-air and one for air-to-refrigeration. 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. | Refrigeration dryers employ two heat exchangers, one for air-to-air and one for air-to-refrigeration. 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. | ||
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==Deliquescent | ==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. | 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. | 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. | ||
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==Desiccant | ==Desiccant Dryer== | ||
The term [[Desiccant Dryers]] refers to a broad class of dryers. Other terms commonly used are regenerative dryer and twin tower dryer, and to a lesser extent [[Absorption Dryers]]. | The term [[Desiccant Dryers]] refers to a broad class of dryers. Other terms commonly used are regenerative dryer and twin tower dryer, 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 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: | ||
The regeneration of the desiccant vessel can be during three different methods: | |||
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==Membrane | ==Membrane Dryer== | ||
Membrane dryer refers to a dehumidification membrane that removes water vapor from compressed air. | Membrane dryer refers to a dehumidification membrane that removes water vapor from compressed air. | ||
Typically, the compressed air is first filtered with a high-quality [[Coalescing Filters|Coalescing Filter]]. This filter removes liquid water, oil and particulate from the compressed air. The water vapor–laden air then passes through the center bore of hollow fibers in the membrane bundle. At the same time, a small portion of the dry air product is redirected along the outside surface of the fibers to sweep out the water vapor which has permeated the membrane. The moisture-laden sweep gas is then vented to the atmosphere, and clean, dry air is supplied to the application. The membrane air dryers are designed to operate continuously, 24 hours per day, 7 days per week. Membrane air dryers are quiet, reliable and require no electricity to operate. | Typically, the compressed air is first filtered with a high-quality [[Coalescing Filters|Coalescing Filter]]. This filter removes liquid water, oil and particulate from the compressed air. The water vapor–laden air then passes through the center bore of hollow fibers in the membrane bundle. At the same time, a small portion of the dry air product is redirected along the outside surface of the fibers to sweep out the water vapor which has permeated the membrane. The moisture-laden sweep gas is then vented to the atmosphere, and clean, dry air is supplied to the application. The membrane air dryers are designed to operate continuously, 24 hours per day, 7 days per week. Membrane air dryers are quiet, reliable and require no electricity to operate. | ||
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== | ==Usages== | ||
* Drying air for use in commercial or industrial processes that demand dry air | * Drying air for use in commercial or industrial processes that demand dry air | ||
:*Telecomm industry (pressurizes its underground cables to repel moisture and avoid shorts | :*Telecomm industry (pressurizes its underground cables to repel moisture and avoid shorts | ||