Spin Flash Dryer
Spin Flash Drier is used for effective and
efficient method of removal of surface or on bound moisture from a feed
product. Spin Flash Driers are designed for continuous drying of cohesive
and non-cohesive pastes, filter cakes and high viscosity liquids. The wet
cake appears granular and gets fluidized. Instantaneous exchange of heat and
mass take place. The dried materials are taken in the collector as powder
PRINCIPLE OF SPIN FLASH DRYING
The Spin Flash Drying is more often in the line of
an agitated fluidized bed system. The drying agitator works as rotor to
break the lumps and the hot air enters at reasonably high velocities to give
dynamic action to dry and disintegrate the product.
Fresh air is sucked through hot air generator, which can be direct or
indirect the nature. The entry to the drying chamber is tangential to give
whirling air suction across the dryer. The hot air generator can be liquid,
solid or gaseous fuel fired. The feed screw pushes the material to the
drying chamber. The drying chamber has a rotor driven from the bottom. The
rotor has specially designed scrapper blades and disintegrator for breaking
the lumpy mass into smaller fragments.
The lumps, which are broken by the rotor, start drying and simultaneously
disintegrating in the stream of hot air.
The airborne fine powder particles get carried to the top of the drying
chamber and a classifier classifies them to the required size. The particles
with larger diameter go back to the chamber, while the fine travel through
with the air for final collection through Reverse Pulse Bag Filters, wherein
almost 100% powder recovery is achieved.
ADVANTAGES OF SPIN FLASH DRYING SYSTEM
- Energy consumption is much less than spray dryers, fluidized bed
dryers, flash dryers, rotary dries, tray driers etc.
- Space requirement for installing this dryer is much less than spray
dryer, pneumatic dryer, fluidized bed dryer and rotary dryer etc.
- It is a completely automatic plant with temperature controller etc.
- Dry product discharge section of the dryer can be installed in your
product packing section, hence cost of transport of dry product to the
finished product section can be eliminated.
- Pulverizing after drying will not be required. The unit will dry,
classify and convey all in a single operation.
- Wet cake can be directly fed from filter/centrifuge to lump breaker
bin, which feeds the cake in to the dryer and hence all intermediate
handling of material can be eliminated. The entire system is closed and
hence any chance of contamination is eliminated.
- Since it is a closed system, wastage and dusting etc. are totally
eliminated resulting in clean environment, zero wastage and total
recovery of product and pollution free atmosphere.
- It is possible to vary the bulk densities also by minor changes in
the classifier situated near the top of the dryer.
COMPONENTS OF SPIN FLASH DRYER
(A) HOT AIR GENERATION SYSTEM
This will consist
of a hot air generator - direct/indirect/finned tube heat exchanger type.
The unit would have to be connected to the dryer by means of a Hot Air Duct
which will have to be insulated.
(B) LUMP BREAKER CUM SCREW CONVEYOR
would be connected to the bottom of suitable wet product storage and
consists of two shafts mounted with special lump breakers meshing with each
other, below a dual screw conveyor will feed material in to the dryer. The
lump breakers shafts and the screw conveyors will run by a single motor with
gear box through a system of meshing gears, bearings, stuffing box etc. This
unit is of a special design for the type of cake and is very robust and
(C) MAIN DRYER
It is a vertical cylindrical
chamber, at the bottom shell is mounted a shaft with a high-speed disperser
and above mounted on it a high-speed scraper. At the top of this section is
a nozzle in to which the screw conveyor feed the material. A tangential
nozzle is provided at the bottom to allow inlet hot air. The drive is
through suitable motor through V - belts and pulleys.
(D) BAG FILTER
Bag Filter for separation of
powder from the air will be provided. The Bag Filter is fully automatic and
self-cleaning with no internal moving parts. The filter will consists of SS
housing with manhole, hopper for product, air inlet and outlet flange, air
nozzle, venture pipes, solenoid valves and all internal compressed air
piping, filter bags and adjustable timer.
(E) ROTARY VALVE
A rotary air lock valve for
discharging material from the filter will be provided. This will be operated
by means of suitable motor with suitable gear box.
(F) EXHAUST BLOWER
A centrifugal exhaust blower
will be provided. Fan will be coupled with suitable totally enclosed fan -
cooled motor by belt drive.
All components comprising the plant
are interconnected with suitable ducting.
(H) CONTROL PANEL
A control panel mounted with
necessary starters, switches, push buttons etc. and pre - wired for all
motors comprising the system.
instrumentation necessary for the safe and simple operation of the plant,
like temperature controller local temperature indicators etc.
- High drying efficiency and low energy costs. The energy efficiency of
such systems is up to eight percent, which is very high for such types
of drying systems.
- Direct drying and no initial diluting.
- Continuous processing with short drying time.
- Ideal for replacing conventional drying systems such as Fluid Bed
Dryers, Pneumatic Flash Dryers etc.
- Pulverizing, conveying, classifying etc. can be done on the same
- Space utilization is most economical and operations are totally
automatic. Most of the time, the product can be directly bagged or sent
for further processing.
- Self-regulating, self-adjusting system, which involves minimal
attention even while operating at capacity.
- The system being under negative pressure, there is no dusting and
therefore no wastage. The area is free from environmental hazards. Clean
operation with minimal manual handling is an important feature of the
- Direct contact dryers for bulk drying of various products such as
inorganic chemicals, bulk drugs, dyestuffs, insecticides foodstuffs etc.
- Chemical industry products like Zinc Carbonates, Calcium Carbonate,
Magnesium Carbonate, Cobalt Carbonate, Zirconium, Red Ferric Oxide,
Aluminum Hydroxide, Lead Sulphate, Zinc Sulphate, Fire retardant Super -
fine Calcium Carbonate, Zinc Oxide, Barium Sulphate, kaolin, Pigment,
Dyestuff, Pesticide, Mancozeb etc.