Why use Bag Filters?
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:
• Sanitary design. All areas of the bag filter are CIP-cleaned.
• Removable top covers for easy access to bags and cages.
• Easy maintenance and no moving parts.
• Scrolled or radial air inlet – to optimize plant layout.
• Low pressure drop – reduces power consumption and noise emission.
• Bags are CIP-cleaned from inside-out – removes powder particles entrapped in the filter material.
• Up to 7 m bags are available – reduce footprint of the building.
• Fluidized bottom – means that even difficult high fat powders can be discharged from the filter.
• 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 shaken off by a compressed air jet stream blown into 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 considera-bly.
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.