What is The Process, Structure and Working of A Rapid Dryer
A Fluid Bed Dryer is designed for
drying powders, crystals, and medium-sized pellets quickly and uniformly. There
are several uses for the Fluid Bed Dryer in the pharmaceutical and bulk drug
industries as well as in dyes and chemicals and Phyto-Chemicals.
In the pharmaceutical industry, a Rapid Dryer
(also known as a fluid bed dryer) is used extensively to decrease the moisture
content of medicinal powder and granules. Wet granules must be dried before
compression into a tablet may take place, as well as to adjust the viscosity
and stickiness of the substance. As the last step before compression into
tablet form and packing, drying is usual.
Perforated beds of wet solid
particles are punctured by high-pressure hot air in the fluidization process.
An airstream is used to raise and suspend the dripping sediments from the
tank's bottom (fluidized state). Direct contact between the moist substance and
the hot gases results in heat transfer. The drying gases pick up the evaporated
liquid and carry it away. Exit gas may be partly recycled in order to conserve
energy.
Drying wet grains, crystals, or
coarse materials is made easier using the Fluid Bed Dryer. Passing high-speed
hot air through a bed of material to be dried causes it to become fluidized and
so dries more quickly.
The induced draught and fresh air
are created by a blower on the dryer's exhaust side that uses no negative
pressure concept. From the bottom of the product container, a stream of heated,
filtered air is emitted. The air distribution plate and the Dutch sieve are
included with this container. The turbulence in the product container is
created by passing the air stream through the bed of the substance. As a result
of fluidization, heated air surrounds each particle, causing rapid and even heating
and drying. Particles can't escape the machine because of the top-mounted
filter bags.
There is a good chance the
ordinary person has never heard of them. Fluid bed dryers, on the other hand,
have made a name for themselves as versatile and trustworthy processing
equipment in the bulk processing industry.
The
Pharmaceutics Industry's reliance on Dryers
Despite the fact that fluidized
bed drying may be utilized in a wide range of sectors, pharmaceuticals have
perhaps benefited the most from its usage. It is possible to consistently
reduce the moisture content of pharmaceutical granules and powders by utilizing
a fluid-bed drier. With the introduction of fluid bed drying technology, drying
periods have been reduced significantly and equal drying conditions have
resulted in a consistent finished product.
Fluid bed dryers are ideal for
drying a wide range of items, but pharmaceutical products in particular. The
system controls incoming air temperature to ensure that moisture evaporates off
the granule's surface at the right pace. A high input air temperature might
lead to a surface crust that inhibits deeper moisture from being transferred to
the surface, slowing rather than speeding the drying process.
Principle
of a Rapid Dryer:
A perforated bottom of a vessel
holding a bed of particle solids or wet granules allows high-pressure hot air
(gas) or ambient air to flow upward upwards better known as a fluid bed drier.
The granules/particles stay suspended in a stream of hot air because the
velocity of hot air is greater than the settling rate of the
granules/particles. A fluidized state describes this state of affairs. Every
granule/particle is thoroughly dried by the heated air that surrounds it.
Structure:
Vertical and horizontal stainless
steel or plastic FBD
fluid bed dryer machines are available. Batch drying is done in a vertical
unit, whereas continuous drying is done in a flat unit. The material is loaded
and unloaded into a removable vessel at the dryer's bottom. The perforated mesh
allows hot, high-pressure air to travel through the vessel. The dry material is
collected by placing bag filters on top of the tank.
Process:
At the bottom of the dryer, a
removable container holds the material to be dried. The hot air is brought up
through the prefilter and into the chamber through the heaters. The
simultaneous operation of a fan is also permitted. An increase in air velocity
causes particles to move in a turbulent manner known as fluidization.
All the while, the air stream is
filled with very tiny granules and particles. When the frictional drag on the
granules/particles is equivalent to the force of gravity, a condition of
pressure is attained. Due to the high velocity of air, the particles are able
to climb to the top of the air stream; this is known as fluidization.
Rapid
dryer benefits include:
1.
2-8 times more efficient than a tray dryer
2.
The drying capacity ranges from 5 to 250 kg
per hour, depending on the model.
3.
Granules/particles that flow freely are
created.
4.
It can also combine the material with great
efficiency for the purpose of mixing it.
5.
It may be used for both batch drying and
continuous drying.
6.
The removable vessel makes it simple to load
and unload materials.
7.
Tray and truck dryers can't keep up with the
higher drying temperatures.
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