Specialized Microencapsulation System Dryers
Drum Dryers
We provide several systems for drying microspheres
and microcapsules that our
technologies are utilized to produce
including batch and continuous
designs. For drying temperature sensitive
microencapsulated products we have developed
very specialized microsphere drum dryers. These
microsphere dryers are especially helpful for
drying microspheres with an oily
core which can leak if overdried.
Additionally, our drum
microencapsulate dryers can
be used for the safe and easy drying
of nearly every kind of spherical
granule. The spherical particles are kept in
motion by conditioned air which
reduces the risk of particle
deformation at the dryer walls to a
minimum. Our microencapsulate drum dryers can be
provided to require very little
space and can be used for batch and
continuous microsphere drying. It is possible to
dry microcapsules with volatile or
sensitive cores to a specified
final residual moisture level.
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Drum Dryer - Case Study
Problem as stated by client:
Flavor filled microcapsules
have some specific properties that make them very diff
icult
to dry. For, as the microcapsules dry, they change in their
physical behavior while losing moisture. The
microcapsules start to become soft and sticky
with a strongly hydrophobic surface. As the
microsphere drying proceeds, the shell shrinks
in diameter. This also means that the weight of
the microcapsule is becoming less which
makes it easier for the microsphere to catch the airflow
exiting the dryer – the microspheres can get lost.
Once dried, the shell of the microsphere is no longer soft and
therefore is sensitive to shocks that occur in fluidizied bed dryers or vibrational drying
systems. On the other hand, in the final states
of drying, the process quickens and it is easy
to overdry the microcapsules. This leads to a
sticky surface since part of the oil phase
diffuses out of the core to the surface of the
microsphere. At this point, the
microsphere surface is strongly hydrophobic. The oils
contained in the flavor act like a glue and so
the whole batch sticks together. No longer
free flowing, no longer easy dosing, just waste
is left.
Our Solution:
To overcome these problems, we
identified the major problems of common drying
technologies when designing a microcapsule dryer:
·
The microsphere products have
to be fluidized in the dryer
·
The microsphere products are
difficult to be fluidized by airflow or vibrational movement
·
The dryer air flow
must be able to handle different densities of
microsphere products
·
The last phase
of the microsphere drying must be closely controllable to avoid overdrying
The
first dryer requirement rules out tray drying. Taken
together, all mentioned statements lead to a
completely new design of an ultimate
Microcapsule Drying System as follows:
Our Microsphere Drum Dryer
Our
Microsphere Drum Dryer works with a large drum that contains
the microspheres. The drum is of a porous design, so that
a dry air current can efficiently get into the drum and flow
around the microcapsules. By gently rotating the
drum, the microcapsules are fluidized. The end
of the process can be measured by controlling
the temperature difference of the inlet and
outlet gas streams and also by measuring the
humidity of the airflow. The microsphere product
can now be dried to a
specified residual solvent content to match each
possible application.
Our
commitment to serve our customers'
needs have resulted in various sizes of
our microsencapsulate drum dryers being made available
including: Laboratory, Pilot and
Production units. The last two are available as
continuous and batch dryers, while the
laboratory unit is only available as a batch
dryer.
A
laboratory microsphere drum dryer is intended for drying
small batches of microcapsules produced e.g.
with the our laboratory Spherisators. It is
capable of drying several kilograms to tens of
kilograms – depending on the unit size – per
day. The intended use of the laboratory
units are the drying of experimental batches or
small, high value microsphere batches.
A
pilot scale microsphere dryer is intended for testing and
optimizing purposes. It can be designed with
multi-zones, continuous or batch processing,
variable heating and all necessary types of
sensors. The main uses for pilot scale dryers
are the development of new products, optimizing
the performance and fixing the necessary
parameters for scaling up to production.
The microencapsulate production scale units
are usually continuously working dryers that are
designed to maintain an even quality for all
products. They are integrated into the control
systems of the microcapsule system but can also be
delivered with a separate control system.
As an
innovative drying concept, our Microsphere Drum Dryers
are suitable for all kinds of products that
change their physical properties quickly while
drying. Sticking and agglomeration is reduced
and pilot scale tests can easily be transferred
to production scale units. It is the perfect
match for our microsphere and microcapsule
units. As a laboratory unit, it makes the drying
of the expensive samples you produce easy
and reliable. As a pilot unit, it provides the
flexibility and fine residual moisture control
for optimizing your existing products and
developing new outstanding ones. And as
a production unit, it works reliably to satisfy
our customers by giving them the final product quality
that they
need – every single day!
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in Easton, Pennsylvania