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| FILMEX II cast film extrusion line |
Combining economy and sustainability is more of a challenge for cast film manufacturers than ever before. The energy consumption of a cast film extrusion line has a major influence on both of these factors. On one hand, energy efficiency is an important aspect of sustainable production. On the other, it also represents a major cost factor particularly in view of the constantly rising electricity prices. The melting process consumes the largest portion of energy during cast film production and cooling is a close second. "The energy consumption during the melting process is a physical constant and there is only minor potential for improvement. In contrast, cooling technology has the greatest potential for optimization. The intelligent and automated cooling technology that we offer with the FILMEX II cast film extrusion line can reduce the energy costs for cooling by up to 70%," explains Torsten Schmitz, Head of Cast Film Extrusion Lines at W&H.
The new approach consists of a combination of a free cooler, a system using low external air temperatures, and a chiller. The system is controlled centrally via the PROCONTROL operator panel of the FILMEX II. An automatic mode always selects the optimum operation. "Our new approach is to recognize the system as a whole. All of the parameters ranging from process temperatures to the outdoor temperature are centrally captured to create an intelligent control system. This enables us to consistently achieve the best energy efficiency," explains Simon Haselmann from the Development Department.
A free cooler requires less than one fifth of the energy of a chiller. The challenge lies in the fact that the free cooler can only be used when the outdoor temperature is lower than the required process temperature. Up until now, the lowest required temperature was always the limiting factor. Schmitz explains, "The casting roll is generally run at a higher temperature than the chill roll for both stretch and barrier films. However, these different requirements could not be addressed separately because only one circuit supplies all of the elements. This resulted in unnecessary cooling, wasted energy and additional costs".
The new approach from W&H resolves this problem through the use of a second cooling circuit. As a result the system can now handle different process temperatures. "Thus, for normal stretch film production, the casting roller can be cooled entirely using the free cooler even at an outdoor temperature of 30° C. This more than halves the work done by the chiller. At outdoor temperatures up to 10° C, the system is cooled using various combinations of the free cooler and the chiller. At temperatures below 10° C, the free cooler handles the entire cooling. On the whole, the free cooler is utilized far more often as a result of the additional cooling circuit and intelligent networking. This saves energy and, thus, money," says Haselmann. He continues, "The chiller itself also operates more efficiently because networking the components means that the water is only cooled down to the extent necessary for the film extrusion process."
The cooling equipment is controlled centrally via the system's PROCONTROL operator panel. The machine operator can easily view and intuitively control all of the parameters. In automatic mode, the machine selects the most efficient operating state itself on the basis of the parameters, consistently safeguarding the highest efficiency. "The investment in the additional cooling circuit and a free cooler pays itself off for a stretch film system in central Europe after around one year. We have not even factored in the added value of sustainability which can be used as an extra sales point and as a benefit for the customer's own brand," says Schmitz, explaining the benefits of the approach.
By offering the intelligent cooling circuit, W&H continues developing the FILMEX II as an intelligent machine. The new generation of the cast film extrusion line was launched at the K 2016. The FILM PERFORMANCE MONITOR was THE innovative highlight, a system that enables integrated data processing throughout the entire process chain from the extrusion to the application and ensures consistent quality. Our offers are the result of a comprehensive development approach, explains Schmitz: "Both developments reflect our vision of Packaging 4.0: intelligent machines, integrated processes, intuitive operation. Alongside the FPM, the new cooling circuit is another product that further enhances our customers' production efficiency".
