Extrusion International 3-2021

42 Extrusion International 3/2021 PELLETIZING Melt Pump Technology for Production of Bioplastic PLA MAAG Group’s pumps are used in the polymerization reaction stage, making sure that theef fi cient Sulzer SMRTMre- actors areworking smoothly inall oper- ating conditions. But they are also used in the devolatilization stage, where, a minimum level is required when unre- acted lactide is removed from the PLA melt to achieve a good product qual- ity. In the last stage, MAAG Group’s melt pumps are used to build up the necessary pressure to process the melt through the downstream equipment, up to the underwater pelletizer. MAAGGroup’s x 6 classmelt pump tech- nology key feature is the reduced back- fl ow to lower the energy consumption. The x6 class melt pump helps to save gressingand the viscosity is continuous- ly increasing in the same. The high ef fi - ciency of the x6 class technology keeps the bearing temperatures lower than in former pump technologies, allowing always a stable fi lm of polymer, lubri- cating the turning shaft. The favorable shaft geometry, where the length over center distance ratio has increased, al- lows theoperationof extractionpumps at a lower fi ll level than it was ever pos- sible before at a given connection size to the vessel. Only like this the PLA can fully be concentrated. But also, the reli- ability has increased. Not only are the bearing surfaces almost 30% bigger, providing a better cushioning, but the pump is alsoworkingwith bigger gaps, allowing potentially small foreign par- ticles entering the system to pass the pump easier without damaging it. The x6 class pumps are the perfect fi t for a modern, sustainable plant producing bio-plastics. up to 50 % energy and reduces mate- rial recirculation in the pump of about 50%. While the reduction of 50% of energy is possible in exceptional cases and in extreme operating conditions only, the trend is true for all the applications whenMAAG Group’s x 6 class technolo- gy is used. With the energy saving, also theCO 2 footprintisreduced.Butx6class pumps offer far more than that. The high ef fi ciency of the pumps is offering a wider operating range as compared to other state of the art technologies. It allows for example that low viscous pre-polymer can safely be processed through the Sulzer plug fl ow reactor when the polymer conversion is pro- Maag Group www.maag.com How to handle plastic waste and the reduction of CO 2 emissions are two of the most important topics our society will be dealing with for the next decades to come. MAAG Group is proud to have supplied its latest state of the art x 6 class melt pump technology for the fi rst fully integrated sugar-to-PLA (polylactic acid) plant in China. The plant is based on a Sulzer technology and key equipment for converting lactide into PLA. The lactic acid and lactide production is made from sugars (in this case won out of locally grown corn). Not only is the plant reducing the carbon footprint because of using plant-based resources instead of hydrocarbons, by usingMAAG Group’s x 6 class gear pump technology, the speci fi c energy requirement is optimized furthermore Swiss quality melt pump fromMAAG Group Bioplastic PLA pilot plant (Source: Sulzer) MAAG Group vacorex ® x 6 class polymer extraction gear pump ideally ful fi lls modern polymer production processes which require polymer pumps that can discharge at high pressure despite very low fi ll level and high vacuum conditions in the reactor/ devolatilization vessel Polymer processes require booster pumps and polymer metering pumps that gently process both high and low viscosity plastic melt through the polymer processing system