Difference between revisions of "Air Dispersion Dryers"

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[[File:Air_Dispersion_Dryers.jpg|thumb|right|200px|Air Dispersion Dryers]]
The '''Air Dispersion Dryers''' are used for drying applications of wet cakes, pastes, sludges and  production of powders from aqueous suspension. Due to the dewatering  mechanism, these dryers provide effective solutions and converted to  either filter cakes, pastes or sludges. These air dispersion dryers are  chosen on the basis of wet deed cake particle size distribution of final  powder and drying curve. The range of air dispersion dryers generally includes  spray dryers, rotary dryers, flash dryers, spin flash dryers, vibrated  fluid bed dryers and fluid bed dryer.
The '''Air Dispersion Dryers''' are used for drying applications of wet cakes, pastes, sludges and  production of powders from aqueous suspension. Due to the dewatering  mechanism, these dryers provide effective solutions and converted to  either filter cakes, pastes or sludges. These air dispersion dryers are  chosen on the basis of wet deed cake particle size distribution of final  powder and drying curve. The range of air dispersion dryers generally includes  spray dryers, rotary dryers, flash dryers, spin flash dryers, vibrated  fluid bed dryers and fluid bed dryer.
===Features===
 
 
==Features==
* Smooth functionality
* Smooth functionality
* Easy operation
* Easy operation
* Durable performance
* Durable performance
==Spin Flash Dryers==
==Spin Flash Dryers==
If the wet cake is a paste or sludge, the [[Spin Flash Dryers]] are the most suited for drying application. The dryer is fitted  with a mechanical agitator which helps to disperse the wet cake without  any need for back mixing of the dry powder. the feeding system  includes a feed tank with agitator and a screw feeder for feeding into  the drying unit. The heart of drying process is cylindrical drying  chamber, where the drying air enters the air distributor. The tangential  air distributor of special design introduces the air as an intense  swirl flow. the simple spin flash dryer is designed to handle  materials that can be suspended directly in air. The drying process  usually is completed in 0. 5 - 2 sees, and the final moisture is  generally in the constant rate drying zone. Various types of spin flash  dryers designs are available based on uniform / non uniform particle  size of the feed / product. the feeding of cake is through  specially designed paddle mixer / screw conveyor with / without rotary  injector depending on rheology of feed material. For difficult to handle  feed materials part of dried powder can be re-cycled. Spin flash dryers  are suited for filter cakes, semi dried powders.
If the wet cake is a paste or sludge, the [[Spin Flash Dryers]] are the most suited for drying application. The dryer is fitted  with a mechanical agitator which helps to disperse the wet cake without  any need for back mixing of the dry powder. the feeding system  includes a feed tank with agitator and a screw feeder for feeding into  the drying unit. The heart of drying process is cylindrical drying  chamber, where the drying air enters the air distributor. The tangential  air distributor of special design introduces the air as an intense  swirl flow. the simple spin flash dryer is designed to handle  materials that can be suspended directly in air. The drying process  usually is completed in 0. 5 - 2 sees, and the final moisture is  generally in the constant rate drying zone. Various types of spin flash  dryers designs are available based on uniform / non uniform particle  size of the feed / product. the feeding of cake is through  specially designed paddle mixer / screw conveyor with / without rotary  injector depending on rheology of feed material. For difficult to handle  feed materials part of dried powder can be re-cycled. Spin flash dryers  are suited for filter cakes, semi dried powders.
==Rotary Dryers==
==Rotary Dryers==
The [[Rotary Dryers]] that are classified as direct  or indirect (air heating method), current or counter current (material  air contact). While using the dryers the material should be dried and  uniformly dispersed over the entire cross-section. These dyers can also  be customized based on the properties of the material.
The [[Rotary Dryers]] that are classified as direct  or indirect (air heating method), current or counter current (material  air contact). While using the dryers the material should be dried and  uniformly dispersed over the entire cross-section. These dyers can also  be customized based on the properties of the material.
===Features===
 
 
==Features==
* Material is Passage through heated air
* Material is Passage through heated air
* Dryer is driven through a girth gear and tyre arrangement
* Dryer is driven through a girth gear and tyre arrangement
* Minimum air leakage
* Minimum air leakage
===Advantages===
 
* Low operating costs* Low maintenance costs
 
==Advantages==
* Low operating costs
* Low maintenance costs
* Ideally suited for high volumes
* Ideally suited for high volumes
* High thermal efficiency
* High thermal efficiency
'''These dryers are used to handle following material'''
'''These dryers are used to handle following material'''
* Sand
* Sand
* Clays
* Clays
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* Ore
* Ore
* Industrial sludge
* Industrial sludge
==Fluid Bed Dryers==
==Fluid Bed Dryers==
The [[Fluid Bed Dryers]] are known for single stage operation and extensively used to convert  solutions, suspensions, and slurries into dry powder within a few  seconds without any intermediate handling. The high speed of the process  and controlled temperature ensure the optimum efficiency of the  process.
The [[Fluid Bed Dryers]] are known for single stage operation and extensively used to convert  solutions, suspensions, and slurries into dry powder within a few  seconds without any intermediate handling. The high speed of the process  and controlled temperature ensure the optimum efficiency of the  process.
===Feature===
 
 
==Features==
* Easy to install  
* Easy to install  
* High functionality  
* High functionality  
* Optimum performance  
* Optimum performance  
* Smooth operation
* Smooth operation
==Spray Dryers==
==Spray Dryers==
The [[Spray Dryers]] offer an effective and efficient method of removal of  surface or on bound moisture from a feed product. Spray dryers are  pneumatic driers having very low residence time within the equipment,  thus flashing off the moisture from the feed. They are used for  efficient drying of moist powders. Slurry, filter cakes, granules, etc.  They operate on varying throughput rates from few hundred kilograms per  hour to hundreds of tons per hour. Low temperature dehumidified air  could be used for heat sensitive products to hot gases with temperature  up to 500 - 600 deg. C. for temperature resistant products. spray  drying equipment comprises of the feeding section normally a screw  feeder, rotary valve, vibratory feeder, etc. Which feeds the wet product  in a controlled fashion into the throat of the flash drier, where it is  mixed with hot air produced by a hot air generator or heat exchanger
The [[Spray Dryers]] offer an effective and efficient method of removal of  surface or on bound moisture from a feed product. Spray dryers are  pneumatic driers having very low residence time within the equipment,  thus flashing off the moisture from the feed. They are used for  efficient drying of moist powders. Slurry, filter cakes, granules, etc.  They operate on varying throughput rates from few hundred kilograms per  hour to hundreds of tons per hour. Low temperature dehumidified air  could be used for heat sensitive products to hot gases with temperature  up to 500 - 600 deg. C. for temperature resistant products. spray  drying equipment comprises of the feeding section normally a screw  feeder, rotary valve, vibratory feeder, etc. Which feeds the wet product  in a controlled fashion into the throat of the flash drier, where it is  mixed with hot air produced by a hot air generator or heat exchanger.
 
 
==Flash Dryers==
==Flash Dryers==
The [[Flash Dryers]] offer an effective and efficient method of removal of  surface or on bound moisture from a feed product. Flash dryers are  pneumatic driers having very low residence time within the equipment,  thus flashing off the moisture from the feed. They are used for  efficient drying of moist powders. Slurry, filter cakes, granules, etc.  They operate on varying throughput rates from few hundred kilograms per  hour to hundreds of tons per hour. Low temperature dehumidified air  could be used for heat sensitive products to hot gases with temperature  up to 500 - 600 deg. C. For temperature resistant products. Flash dryers  comprises of the feeding section normally a screw feeder, rotary valve,  vibratory feeder, etc. Which feeds the wet product in a controlled  fashion into the throat of the flash drier, where it is mixed with hot  air produced by a hot air generator or heat exchanger.
The [[Flash Dryers]] offer an effective and efficient method of removal of  surface or on bound moisture from a feed product. Flash dryers are  pneumatic driers having very low residence time within the equipment,  thus flashing off the moisture from the feed. They are used for  efficient drying of moist powders. Slurry, filter cakes, granules, etc.  They operate on varying throughput rates from few hundred kilograms per  hour to hundreds of tons per hour. Low temperature dehumidified air  could be used for heat sensitive products to hot gases with temperature  up to 500 - 600 deg. C. For temperature resistant products. Flash dryers  comprises of the feeding section normally a screw feeder, rotary valve,  vibratory feeder, etc. Which feeds the wet product in a controlled  fashion into the throat of the flash drier, where it is mixed with hot  air produced by a hot air generator or heat exchanger.
==Vibrating Fluid Bed Dryers==
==Vibrating Fluid Bed Dryers==
The [[Vibrating Fluid Bed Dryers]] are used for fluidization of materials which are difficult to handle in a static fluid bed dryer.
The [[Vibrating Fluid Bed Dryers]] are used for fluidization of materials which are difficult to handle in a static fluid bed dryer.
===Physical Properties===
 
 
==Physical Properties==
These materials are often characterized by having one or more of the following physical properties:
These materials are often characterized by having one or more of the following physical properties:
* Wide particle size distribution
* Wide particle size distribution
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* Stickiness or thermo plasticity of the particles
* Stickiness or thermo plasticity of the particles
* Pasty properties of the wet feed
* Pasty properties of the wet feed
In the vibrated fluid bed dryer, the material is easily transported  through the dryer by the combined effect of fluidization and vibration.  The fluidization velocity can be judiciously selected, to minimize  entertainment of the smaller particles, to avoid gas bubbling m the  fluid bed thereby minimizing attrition. The residence time can be  adjusted, by varying the bed height, through the overflow weir position.  A cooling section can also be provided, by partitioning of the plenum  chamber.
In the vibrated fluid bed dryer, the material is easily transported  through the dryer by the combined effect of fluidization and vibration.  The fluidization velocity can be judiciously selected, to minimize  entertainment of the smaller particles, to avoid gas bubbling m the  fluid bed thereby minimizing attrition. The residence time can be  adjusted, by varying the bed height, through the overflow weir position.  A cooling section can also be provided, by partitioning of the plenum  chamber.
'''Typical products handled:'''
'''Typical products handled:'''
* Salt
* Salt
* Milk products (used as a secondary dyer)
* Milk products (used as a secondary dyer)
* Chemicals
* Chemicals
* Tea
* Tea
Fluid bed dryer is suited for powder, granules with average particle  size 50 - 2000 microns. If the feed material is sticky and having wide  particle size distribution. Vibro fluid bed dryer is the most suited,  where vibration helps the movement of solids and drying.
Fluid bed dryer is suited for powder, granules with average particle  size 50 - 2000 microns. If the feed material is sticky and having wide  particle size distribution. Vibro fluid bed dryer is the most suited,  where vibration helps the movement of solids and drying.
===Operation===
 
 
==Operations==
* Material is easily transported through the dryer due to fluidization and vibration
* Material is easily transported through the dryer due to fluidization and vibration
* Fluidization velocity can be judiciously selected to minimize entertainment of the smaller :particles
* Fluidization velocity can be judiciously selected to minimize entertainment of the smaller :particles
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* Residence time can be adjusted by varying the bed height, through the overflow weir position.
* Residence time can be adjusted by varying the bed height, through the overflow weir position.
* Provided with cooling section by partitioning of the plenum chamber.
* Provided with cooling section by partitioning of the plenum chamber.
===Advantage===
 
 
==Advantages==
* Well suited for constant
* Well suited for constant
* Well suited for failing rate drying
* Well suited for failing rate drying
* By preheating the air, the residual moisture can be reduced
* By preheating the air, the residual moisture can be reduced
* Can fluidized well the solids having a well defined particle size
* Can fluidized well the solids having a well defined particle size
==Laboratory Spray Dryer==
==Laboratory Spray Dryer==
The [[Laboratory Spray Dryers]] follow some basic principles.
The [[Laboratory Spray Dryers]] follow some basic principles.
===Principle===
 
A peristaltic pump delivers liquid from the sample container to the 2  fluid nozzle mounted on the drying chamber. Compressed air from the  inbuilt compressor is also supplied to the nozzle, resulting in  atomization of the liquid into a fine spray. Air from the blower is  heated by an electrical air heater and blown through the drying chamber.  Due to the large surface area, drying is very rapid, resulting in a  sharp drop in temperature. The dry powder particles are separated from  the air in the cyclone separator and collected in the glass collection  bottle. The exhaust air is directed through a flexible ss hose into the  atmosphere. A bag filter can be provided for secondary powder  collection.  
 
===Construction===
==Principle==
A peristaltic pump delivers liquid from the sample container to the 2  fluid nozzle mounted on the drying chamber. Compressed air from the  inbuilt compressor is also supplied to the nozzle, resulting in  atomization of the liquid into a fine spray. Air from the blower is  heated by an electrical air heater and blown through the drying chamber.  Due to the large surface area, drying is very rapid, resulting in a  sharp drop in temperature. The dry powder particles are separated from  the air in the cyclone separator and collected in the glass collection  bottle. The exhaust air is directed through a flexible ss hose into the  atmosphere. A bag filter can be provided for secondary powder  collection.
 
 
==Construction==
* The blower, electrical air heater, air compressor and the pump are placed in a stainless steel panel, with free and easy access
* The blower, electrical air heater, air compressor and the pump are placed in a stainless steel panel, with free and easy access
* The air entering the panel is filtered through a fine cloth filter
* The air entering the panel is filtered through a fine cloth filter
* The chamber and cyclone are of borosilicate glass with clamp fillings, designed for easy assembly and removal
* The chamber and cyclone are of borosilicate glass with clamp fillings, designed for easy assembly and removal
* The peristaltic pump is mounted on the front of the panel with easy accessibility
* The peristaltic pump is mounted on the front of the panel with easy accessibility
===Operation===
 
 
==Operations==
The dryer has ease of operations. The inlet air temperature is precisely  controlled by the inlet temperature pid controller. The panel includes:
The dryer has ease of operations. The inlet air temperature is precisely  controlled by the inlet temperature pid controller. The panel includes:
* Inlet temperature controller
* Inlet temperature controller

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