The SANICIP™ Bag Filter
All spray drying plants are equipped with powder
separators to collect the powder entrained in the exhaust air. Until a few
years ago cyclones were the preferred choice for this task. Cyclones were cheap
and they could be wet cleaned. But they could not live up to the ever stricter
requirements put forward by authorities in order to reduce powder emission, now
down to 10 mg powder/Nm3 of process air.
SANICIP™ CIP-able filters
“Police” bag filters or wet scrubbers were installed,
but this just added to the investment and operational costs, as product
recovered here ends up as waste. That is why GEA Niro has developed the
SANICIP™ CIP-able bag filter replacing the cyclones. The SANICIP™ bag
filter is a reverse jet type filter, designed in accordance with the strictest
sanitary requirements given by the leading international agencies in EU and
USA.
Features that make SANICIP™
unique:
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Sanitary design. All areas of the bag filter are
CIP-cleaned.
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Removable top covers for easy access to bags and cages.
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Easy maintenance and no moving parts.
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Scrolled or radial air inlet – to optimize plant layout.
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Bags are CIP-cleaned from inside-out – removes powder
particles entrapped in the filter material.
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Up to 7 m bags are available – reduce footprint of the
building.
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Fluidized bottom – means that even difficult high fat
powders can be discharged from the filter.
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Heated cone to avoid powder build-up and bacteria growth.
Working Principle
The exhaust air containing some powder particles is passed
through the GEA Niro SANICIP™ filter. It consists of a cylindrical bag housing
with spiral shaped or radial air inlet, clean air plenum on top, and a conical
bottom with fluidized powder discharge. During operation the product collected
on the outside of the filter material is blown off by a
compressed air jet stream from the inside of each bag by means of a
specially designed reverse jet air nozzle (patented) positioned above the bag.
The result of the SANICIP™ filter
process
This results in a very even discharge of
powder. The frequency and duration of the cleaning sequence can be adjusted to
suit actual running conditions. The result is a low pressure drop across the
filter, i.e. reduced energy consumption and noise emission. Another special
feature in the SANICIP™ bag filter is that the bags are wet-cleaned from the
inside towards the dirty outside (patented) by means of a clean water spray,
reducing the overall amount of CIP water considerably.
No powder loss
All the fines discharged from the bag filter are
returned to the process. This means that no powder is lost as waste, but sold
as first-class product. Retrofits of old plants equipped with cyclones and
traditional bag filters or wet scrubbers can now be done by replacing the old
exhaust system by a GEA Niro SANICIP™ bag filter.
Other advantages
Full utilization of
energy recuberation is now possible if a heat recovery system is installed after the SANICIP™
bagfilter. As there are practically no powder particles left in the exhaust air
the heat recovery system can be designed so that the air with the moisted - on
vapor form - can be cooled to below the condensation temperature and all the
entrained energy can be reserved and reutilized.