Sanitary product recovery of powder for spray dryer in the food processing industry.
Spray dryers in the food, dairy and pharmaceutical industry need highly efficient dust filters in order to prevent fine dust particles escaping to the outside. Bag filter are not a valid solution since they clough easily due to the fine dust particles. In addition, the bag filters need to be changed frequently for sanitary reasons.
The electrostatic KMA AAIRMAXX® ESP is a highly effective and cost-saving alternative to bag filters. The spray drying process creates fine dust particles such as e.g. milk-, cocoa-, coffee powder which can be filtered and recuperated thanks to sanitary product recovery. As a result, both the energy efficient air filter system and the economic product recovery save operating costs.
This is how our air filter system works:
The exhaust air coming from the spray dryer and the cyclone(s) enters into the AAIRMAXX® filter at the bottom. The filter is made of a group of stainless steel tubes. The number of tubes depends on the required exhaust air capacity.
In the centre of each tube there is a stainless-steel laser cut ionization electrode. During the operation of the filter it creates a powerful electrostatic field, making the dust in the airstream move to the walls of the tubes. Hence the inside walls of the tubes act as a dust-collector. Due to the automatic filter cleaning system a fast and sanitary product change is possible.
Lower energy costs + effective product recovery
Product changes in the spray dryer and frequent cleaning of the system for sanitary reasons need a quick and efficient cleaning system.
KMA AAIRMAXX®ESP has a unique CIP-system which has been designed in co-operation with leading European food processing companies in accordance with highest sanitary standards. The walls of the collector tubes are equipped with a number of jets for highly efficient filter cleaning.
The jets are made in special sanitary design and ensure a quick and thorough cleaning of all parts of the collectors and the centre electrodes. The optimised and echelon formed configuration of the jets prevents the creation of spray shadows. The CIP-system is designed as an automatic operation without need of manual cleaning time. Water feed is usually supplied by the central washing system of the spray dryer unit. The rinsing process with brine and acid requires only a couple of minutes. Furthermore, the subsequent drying process needs only a little time, as the only parts that need to dry are metal walls of the tube. In this way, even multiple product changes per day are possible.
During the extraction air mode of the spray drayer, there is a powerful electrostatic field which makes the dust in the airstream move to the walls of the tubes. Hence the inside walls of the AAIRMAXX ® ESP tubes act as a dust-collectors.
For frequent removal of the dust, each tube is equipped with pneumatic impactors. The dust flows down from the walls into the hopper underneath the tubes and passes a discharge airlock. The recovered dust flows to the central dust discharge and collector system.
The efficient recovery of the product powder is an essential cost advantage and reduces the payback period drastically.
In times of energy shortage and rising energy prices, the effective heat recovery is an issue of increasing importance in the planning and operation of technical equipment. The exhaust air still contains a very high temperature level, especially during the spray drying process.
In a system with integrated energy recovery, the heat gets transferred to the supply air of the spray drying process by means of a hydraulic circuit system. This is achieved with two independent multi-plate heat exchangers in the exhaust and supply air current. In this way, the air is filtered in an energy efficient way while saving a lot of energy costs during the spray drying process.
To increase the energy efficiency of the system, it can be enhanced when combined with an Ambitherm® Heat Pump.
KMA AAIRMAXX® ESP filters can be used for replacing bag filters or as a final filter behind a cyclone in order to retrofit and upgrade an existing spray dryer plant. The replacement offers impressive benefits and a short amortisation period due to extra plant yield, caused by product recovery, reduction of energy costs and lower cleaning downtimes.
Consequently KMA AAIRMAXX®ESP filters allow for a short payback period due to: