PETpla.net Insider 04 / 2010

PREFORM PRODUCTION 18 PET planet insider Vol. 11 No. 04/10 www.petpla.net Energy: first things first … Energy saving was and always has been an important topic for the company. The first step was to assess the potential for energy saving in terms of screw geometry, the screw drive, the clamping unit and the robotics. Savings of up to 30% were achieved in these areas. Compared to the situation ten years ago, the energy required to produce a kilo of PET has been more than halved! As a result of this movement towards reducing energy consump- tion on the PET-Line systems featuring significant energy values amounting to less than 200Wh/kg PET have been achieved. Moreover, the potential for deter- mining product energy consumption with an accuracy of +/- 5% as early as the offer phase has also been explored. Next: … the other suppliers The next stage was to look at energy consumption of the whole aux- iliary equipment. Particular attention was paid to the material dryers, where the amount of energy required to plas- ticate the material is significant. Studies undertaken with the manufacturers of materials dryers have shown that the drying of the raw material is another key element that merits attention. Just as significant is the energy input into the raw mate- rial, because there is nowhere that the PET material can absorb energy in a gentler way than in the dryer hopper. In a best case scenario, it is even pos- sible to achieve a slight reduction in the proportion of acetaldehyde (AA) proportion as early as the heating up phase. As a result, the machine requires correspondingly less energy to bring about fusion in the material. This means that, due to the (now) lower proportion of energy that is still to be transferred into the material via the plastication unit, the material will plasticate considerably more gently resulting in a further reduction in the occurrences of AA. These findings have helped to make it possible to formulate, together with the dryer manufacturers, a pre- cise definition not only of the state of dryness of the raw material but also its energy content as it is transferred from the dryer for plastication. Estab- lishing the energy input in the dryer hopper is extremely costly, and dif- ficult to achieve, which is why Netstal has developed its own monitoring facilities. In addition to the dryer, there is potential for more savings in the cooler unit used for cooling the mould. This could only be achieved by close cooperation with both manufacturers. The primary stage involved mould Energy savings and improving cost efficiency Over the past two years, the Swiss company Netstal-Maschinen AG has launched a number of new developments aimed at saving energy and improving cost efficiency in the manufacture of PET preforms. We look at how they got on. * Netstal moves towards reducing energy consumption on their PETline systems C O S T EFFICIENCY ENERGY EFFICIENCY