One of the global leading auxiliary extrusion equipment systems suppliers, BKG Bruckmann & Kreyenborg Granuliertechnik GmbH, part of the Kreyenborg Group, has developed an eco-friendly and energy-saving PET crystallizing device
Development of a new pelletizing procedure CrystallCut, allowing to perform PET pelletizing and crystallizing during the same stage, has become a decisive step for the reduction of costs during the PET production process. With the pelletizing and crystallizing procedure CrystallCut (CC), the crystallization of PET is performed by using the energy of latent heat and thus to have lower production costs. Thanks to this new crystallization procedure, the produced pellet has modified properties which have a positive effect on the processing steps next in line. With an underwater pelletizing system, PET polymer melt is processed into pellets. Exact here, the new CrystallCut technology comes into operation. Via a conveyor pipe and with high speed, the PET pellets are transported to a pellet dryer. The flow medium is hot water with a temperature of up to 95 °C. An essential aspect for the effectivity of CrystallCut are relatively short conveying distances between pelletizing chamber and pellet dryer. The PET pellets leave the pellet dryer with a temperature of up to 180 °C and are guided into the crystallization chute. Then, the PET pellets are circulated in the individual chambers avoiding an adherence of the pellets. The pellets are crystallized without any energy supplied for heating. It is noticeable that they independently crystallize from inside to outside. After this process, the PET pellets are crystallized to approx. 40 % and have a temperature from 140 to 180°C. It makes possible the direct transport of the hot PET pellets to SSP. As it is shown at figure 1, compared with conventional procedures, using of CrystallCut technology provides the saving of energy of approximately 30 % Based on a 600 tons per day line, this results in a saving of energy of approximately 1,000,000 euro annually, based on an energy price of 0.125 euro/kWh. With CrystallCut, the PET pellet production breaks new ground regarding, saving of energy and quality of the pellets and gives great competition advantages. Numerous systems, which are already in operation, are showing this new trend.
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