PAGEV Türk Plastik Endüstrisi Kongresi 2011 (Henning Stieglitz, Battenfeld-Cincinnati)

Thank you very much. Ladies and gentlemen, first of all I would like to thank the organization committee for the invitation and the possibility to give a presentation here. I hope you are still ready for information even if we are close to lunch because I think I have some interesting details for you. My topic today will be efficient extrusion, solutions for lower energy consumption. I will try to avoid the word sustainability. My presentation will be structured as follows: first, motivation; second, the extruder as the biggest energy consumer and potential savings; third, holistic line concepts; fourth, monitoring. Let me start with the motivation. Here you see the energy cost development in Germany: in 2003, 4 cents per kilowatt-hour; now around 10 or 11 cents. I assume the increase in Turkey may not be as big, but energy costs will increase due to resource shrinkage. Also, the efficiency of an extrusion line improves with higher output because components run at their nominal points, decreasing production costs. In a flat film extrusion line for thermoforming sheets, the main drive consumes 64% of total energy; with co-extruder drives, up to 90% of the energy is consumed by the drives. So the extruder drives are the biggest energy consumer. Now, what potentials do we see to improve extruder efficiency? Comparing a 120 mm standard single-screw extruder to a 75 mm high-speed extruder (circumferential speed above 1.5 m/s, RPM above 400) shows an efficiency difference of 40% at low output and still 10% at high output. These high-speed extruders help save production costs. Another advantage in the last two to three years is the use of gearless torque motors instead of motor-gearbox combinations, which can increase efficiency by 5 to 6% especially at part load, with lower noise, compact design, and less maintenance. Smaller high-performance extruders also reduce material consumption during color change: for a 75 mm extruder running at 1.5 tons per hour, material loss is 150 kg, compared to 1.3 tons for a 180 mm standard extruder, and the time for color change is much lower. The weight difference is also significant: 3 to 4 tons vs 20 to 25 tons, making maintenance and handling easier. To summarize, high-performance extruders require less space, lower investment and spare part costs, reduced residence times, faster startups quick material and color change, easier handling, less energy consumption, and better product quality. Now let's come to holistic line concepts. It is not enough to look at single components; you need to look at the whole line. For pipe extrusion, we developed a modular concept with three options to save up to 50% in downstream length and energy. One system is cooling of the pipe from the inside and cooling of the melt. Using water in the die head and sucking air through the pipe, we can cool the inner surface. The air heats up to about 120°C and can be used for drying material or heating the building. An example for a 160 mm pipe with 14.6 mm wall thickness: without internal cooling, the inner layer cools slowly and finishes at 40 to 60°C; with internal cooling, the temperature at the end is around 20°C. This allows the producer to increase line speed and output. The investment costs are comparable to standard lines due to omitting some spray bars. Advantages include increased efficiency, higher line speed, reduced line length, reduced material consumption due to more precise wall thickness, improved energy utilization, the possibility to use standard PE materials instead of low-shrink materials, less air pollution on the shop floor, and the ability to use waste heat. We also developed a new cooling process where spray baths are connected in series with water pumped from the end to the beginning. This reduces water flow from 20 cubic meters per hour to 1.5 cubic meters per hour, and the water temperature increases from 20°C to 60°C. This allows free cooling without a huge chiller, saving energy. Finally, monitoring: to decrease energy consumption, you need to know where you consume it. So you need data acquisition, visualization, database building to analyze components and processes, and optimization. This requires intelligent measuring devices directly on the machine.