Dehumidification - A prerequisite for high quality spray

Case Study: AB Cernelle, Sweden
Optimal climate conditions for spray
drying around the year
• Stable and fully humidity
controlled drying climate
• Shortest possible drying time
• Maintains high product quality
• No caking of product inside spray
• No bacterial growth thanks to low
and controlled humidity
• Upgrade of dehumidification
solution saves up to 75% energy
Dehumidification - A prerequisite for high quality spray drying
Swedish AB Cernelle is the founder of
superior pollen extracts for medical
treatment. Started in 1953, the company
had a vision that purified extracts of
pollen would be of value to improve
human health.
Methods where created for collection
and process of pollen in large scale in
order to develop active pharmaceutical
ingredients, Cernitin pollen extracts.
Munters Air Treatment Division,
Today Cernelle is passionately commited
to developing and delivering cernitin
pollen extracts drugs for effective relief
of lower urinary tract symptoms caused
by benign prostate abnormalities, such as
prostate hyperplasia, chronic prostatitis
and pelvic pain syndrome.
Cernitol, Cernitol Novum, Cernilton are
registered pharmaceutical drugs based
on Cernelle´s unique and superiour
pollen extracts.
The product Cernilton is used as first line
treatment in Japan today. Over 200
million tablets were sold in Europe and
Asia during 2015.
Cernelle has dedicated facilities
for pollen extraction and dry
pharmaceutical production of tablets,
capsules and powder. The company
is certified by the Swedish Medical
Product Agency.
Since March 2005 the company is a
subsidiary of Backahill AB.
Spray drying of pollen
On the premises close to Ängelholm
in Sweden, tablets as well as bulk
products for export markets are being
manufactured. The raw pollen material
that originates mainly from rye, corn
or timothy grass, is undergoing a
complicated process to separate and
extract the pollen. The liquid pollen
extracted during a compression
and filtering process will need to be
transformed into powder and then
mixed with other ingredients before
tableting. This process is performed in
a spray drying system (spray tower).
The fluid pollen extract is stored in
tanks before introduced into the spray
drier. For a successful and reproducible
result, the spray drying process is very
dependent on accurate control of both
temperature and humidity.
The air used in the spray drier is all
supplied from a Munters desiccant
dehumidifier at a temperature of 123°C.
The dry air is delivered into the top of
the spray drier just above the spray
nozzles. The water content in the air
has to be kept as low as 5g/kg to
secure the correct powder quality.
Ted Johansson and Munters service technician Roger
Johnsson next to the new ML23 dehumidifier.
system of the dehumidifier started to
become outdated and despite some
updates to optimise the operation of
the system, Munters recommended to
replace the MX dehumidifier with a
more modern and energy efficient ML
Modern and energy efficient
A desiccant dehumidifier type ML23
was installed in a small room next to
the spray drier to avoid the negative
impact from the sugar dust. The
ML23 is a modern dehumidifier that
offers numerous advanced features
as standard including an integrated
PLC unit that displays over 10 alarm
indicators, an operating time counter, as
well as an optional remote control.
The spray tower in which 13 tons of pollen powder is
produced annually by means of dry air from a Munters
desiccant dehumidifier.
Without humidity control, the product
would hold a higher water content,
resulting in the product clogging and
building up on the inside of the spray
drier. This caking would need cleaning
and also increase the risk of bacterial
and mold growth, compromising high
hygiene standards in production.
The pollen leaves the spray drier as a
92°C warm pollen powder. Before it
can be packed and made ready for
further processing, it is cooled down by
means of a cyclone placed directly after
the spray drier.
Dry air to control drying process
At Cernelle, the spray drying has
always been performed with dry air
from a Munters desiccant humidifier. For
many years a MX2100 dehumidifier
was placed impractically high above
and close to the spray drier. Over the
years, the dehumidifiers electrical parts
started to suffer from the content of
sugar in the air. Sugar is being added
to the drying process and the fine
sugar powder caused problems when
adhering onto control boards inside the
dehumidifier. Furthermore the control
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At Cernelle a remote display has been
placed in a central control room. From
here, both read-outs and changes to
settings can easily be carried out. The
dehumidifier also has integrated heat
recovery, making it extremely energy
Energy savings up to 75%
Cernelle experience huge benefits after
installation of the new dehumidifier.
Not only is the remote operation of
the unit so much easier, but the energy
costs have been reduced by up to 75%.
When no dehumidification is needed the
new ML23 system can run in ventilation
mode only. This feature minimises
operation costs and was not possible
with the former MX dehumidifier.
Ted Johansson, responsible for
technique and maintenance at Cernelle,
highly appreciates the new solution
and also the financial advantages
of the more modern and up-to-date
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