Spray
drying is by definition the transformation of
feed (which is in liquid state) into a dried
particulate formed by spraying the feed into
a hot drying medium.(In short, spray drying
involves atomization of feed into a spray, and
contact between spray and drying medium in co-current
flow resulting in moisture evaporation).Evaporation
takes place because of vast surface area of
droplet in a spray.It is a non-step,continuous
particle processing operation involving drying.The
feed can either be a solution, suspension or
paste.The resulting dried product confirms to
powder, granules or agglomerates, the form of
which depends upon the physical and chemical
properties of the feed and the dryer design
and operation. |
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| Advantages
of Spray Dryer |
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- The
powder quality remains constant irrespective
of the design of the dryer.
- It
is a continuous and easy process.
- Energy
Efficient.
- Compact.
- Require
Minimum Maintenance.
- Save
Labour .
- It
can be used for both, Heat sensitive and Heat
Resistant products.
- Custom
designed to suit your product.
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| Size
of the Dried Particle |
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Basically
two type of atomizers:
CENTRIFUGAL and NOZZLE and three models:
- Centrifugal
/ DISC (low pressure)
- NOZZLE
( high pressure)
- VERSATILE
(Combination of Centrifugal and Nozzle) are
offered by us.
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Typical
diagram of spry dryer equipped with rotary at
omizer (Centrifugal) and Nozzle atomizer is
shown in figures. powders comprising of small
or Medium sized particles are product by a centrifugal
atomizer. Coarser po Powder is product by fountain
drying using pressure Nozzle atomizer. |
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Top |
| Process |
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| Spray
Drying consists of four process stages : |
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- Atomization
of feed into the spray.
- Spray
– Air contact (in co- current flow).
- Drying
of spray (moisture evaporation).
- Separation
of dried product from the air.
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Each
stage is carried out according to dryer design
and operation, and together with the physical
and chemical properties of the feed, determine
the characteristics of the dried product.
The liquid feed is pumped from the fed tank
to the
a) centrifugal atomizer or
b) pressure Nozzle within a ceiling air disperser
through which the drying air enters the drying
chambers . The indirectly heated air is drown
from the atmosphere by a fan.
Due to large surface area of contact between
droplet and hot air, drying is a accomplished
in few second and the product leaves the drying
chamber as a free flowing powder . the majority
of the dried product falls to the base of the
chamber and is collected from chamber bottom.
The product fines entrained in the air passes
to the cyclone for separation and the remaining
product is collected from the cyclone bottom
. Alternatively you may choose single point
collected also to get different sizes of the
particle .
Further any escaped fines are trapped in scrubbing
system with the help of water spray and solution
can be remixed with liquid feed.
The spray drier thus completely eliminates filtration
, grinding , etc . and the system is pollution
free .
All processing conditions such as temperature
profile , feed rate , air velocity , atomizer
speed are conventionally monitored and displayed
on central instrument panel . the running systems
can be visualized on the MIMIC diagram . the
system is designed with interlocks and instruments
For auto / manual control. |
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| Click
Here for Spray Dryer Enquiry Form |
