PETpla.net Insider 07+08 / 2012

MATERIAL / RECYCLING 30 PET planet insider Vol. 13 No. 07+08/12 www.petpla.net Award-winning energy savings with spherical pellet A cut above CrystallCut is a pelletizing and crystallization process in which the crystallization of the PET is achieved using the latent heat energy already present in the pellets. The equip- ment line-up is similar to a traditional polymerization and extrusion line but the difference is in the cooling of the polymer after it exits from the extruder die. During the first two seconds the plastic melt loses two-thirds of its latent heat energy, which means that the residence time of the pellets in the process water should be kept to an absolute minimum in order to later attain the highest possible degree of crystallization. For this reason, Crys- tallCut equipment is usually employed with an underwater pelletizing system. The pellets exit from the dryer and enter the crys- tallization conveyor at an average temperature of more than 135 O C. The superficially cooled pel- lets are kept in constant motion, which triggers the crystallization process to proceed without any addi- tional energy requirement. Only the heat energy present within the pellets is used, crystallizing from the core to the outside and resulting in a 40% degree of crystallization. BKG says that Crys- tallCut enable energy savings of around 20%, compared to conventional extrusion equipment for the manufacture of PET pellets. Additional energy cost savings of around 5% can be realised during subsequent processing in the injection mould- ing machine, because the microstructure that results from the crystalli- zation action in the conveyor requires significantly less energy to re-melt the pellets. The total energy savings of around 25-30% translate into about 25gWh per year at a 600 t/day plant. BKG further claims that less space and a lower total capital investment is required for a CrystallCut system than for the conventional combination of pelletizer and crystallizer. BKG says that installed Crystall- Cut equipment around the world pro- duces 10,000t of PET pellets/day, on machines with outputs ranging from 250-2,0000kg/h. www.kreyenbourg-group.com www.bkg.de BKG Bruckmann & Kreyenborg, which manufactures processing machinery in Muenster, Germany, says that its BKG CrystallCut process could help a plant with a production capacity of 600t/day to achieve energy sav- ings of 25 gWh/year of operation, compared with existing pelletizing and crystallising technology. The process has been awarded the prize for the “most innovative, energy- saving plastics processing equipment of the last decade (2002-2012)” by Plastic Technology China in cooperation with the Vogel Media Advertising Co. Ltd. The BKG crystall cut process has been awarded by Plastic technology China