International large-scale projects for plastics production plants are extremely complex. These plants, which total investment costs can very well reach hundreds of millions, are generally supervised by engineering, procurement and construction (EPC) companies as well as by the process licensors. Innovative plant engineering companies assume an increasingly important role in the process design of such plants.
Unlike many plant engineering companies, Zeppelin Systems goes beyond just simply meeting the specifications of the EPC companies. "In the end, it's the plant operator who is left with the results. A process that has not been optimally planned will affect the operator's daily business. Adjustments are hardly possible to make afterwards due to the size of the plant," Michael Pfrieger, Business Unit Manager Polyolefin Plants at Zeppelin Systems, explains. The company based in Friedrichshafen, Germany, is therefore taking a different approach and doesn't shy away from suggesting alternative plant designs to the given specifications. The company benefits from decades of international experience in manufacturing plants for plastics producers. "We know which technology is state-of-the-art and this is why we were often able to help the end customer lower his investment and operation costs," Pfrieger says and adds two examples to illustrate his point:
Example: Production of polypropylene pellets
Although removing monomers from plastics is a common process, there is still room for optimization. The EPC specification was to remove the monomers right after the production process and then to store the powder in a storage silo. This closed loop process design, however, required silos capable of withstanding a very high pressure, which naturally leads to very high costs. The extrusion process in which more monomers are formed was placed after storage. Zeppelin therefore suggested that degassing be placed at the end of the extrusion process. After going through underwater pelletizing, the pellets are now heated, degassed and cooled again in a process integrated in the conveying system before they are transported to the mixing silo. The plastics producer not only benefitted from lower investment costs (expensive pressurized silos no longer necessary), but also from an improvement in the quality of the end product. "We were only able to suggest these plant modifications because we have field experience in the matter. We also simulated the process in our Technology Center and were able to confirm that it does work," Pfrieger explains.
Example: Production of PE and PP pellets
Another example comes from storage. In the original EPC specifications, four bagging silos with four separator systems were foreseen. For the EPC companies, this was a reasonable approach as simple device multiplication reduced some planning costs for them. However, there was only one production line in the plant, which meant only one separator could be used. Zeppelin suggested using one central separator system that feeds gravimetrically into the four bagging silos. Although the steel structure was slightly more expensive, it allowed considerable savings by reducing the amount of separator systems from four to only one. "This is an excellent example how to reduce investment and operating cost without compromising on flexibility," Pfrieger emphasizes.
Zeppelin Systems always has the total system and the target technology in mind when planning a plant and decides for the optimal solution for process and operator rather than just executing specifications. "We strive for a balance between proven systems and individual solutions," Pfrieger explains the strategy. "Like an architect we decide for the best fitting subsystem or process for the plant."
Zeppelin Systems, the plant engineering specialist from Friedrichshafen, Germany, will demonstrate how to realize large plants for plastics at this year's K, hall 9, booth B41 in Düsseldorf, Germany.