battenfeld-cincinnati impressively demonstrated jointly with its partner companies Labotek and SABIC the substantial improvements in reducing energy consumption achieved by the machine manufacturer over the last few years at an Open House in February 2013 in Bad Oeynhausen, Germany. The latest-generation PO pipe extrusion line on display consumes at least 30% less energy than a predecessor model. Some 75 visitors gathered information about ways to operate a pipe extrusion line in an ecological as well as economical way.
With an annual production time of 7,000 hours, about 300,000 Euros can be saved in electricity costs alone if a pipe extrusion line is equipped with the components presented by battenfeld-cincinnati on this occasion. They were demonstrated on the example of a coextrusion line producing a 2-layer pipe for pressure pipe applications, which reached an output of 750 kg/h and a line speed of 0.93 m/min. Major contributors to the enormous energy savings were the uniEX 35-30 and solEX 75-40 extruders used, as well as the special helix 250-3 VSI-T+ pipe die with an EAC (efficient air cooling) internal cooling system, and the Green Pipe downstream equipment.
Extruders from the uniEX single screw series with a 30 D processing length are extremely versatile thanks to their wide processing window. They are highly energy-efficient because of their AC motors equipped with air-cooled frequency converters. The models from the solEX series with their 40 D processing units offer the ultimate in terms of efficiency. Here, energy-efficient operation is ensured by an AC motor with a water-cooled frequency converter.
battenfeld-cincinnati has revised its helix VSI-T pipe dies, the proven equipment for PO processing, with a special focus on energy consumption. The core component of the new helix 250 VSI-T+3-layer pipe die is a cooling basket installed between the spiral mandrel and the lattice basket. The EAC internal cooling system blows in cold air for internal pipe cooling and subsequently transfers the heated air to the Labotek material drying system. This internal pipe cooling system also improves pipe quality; the sagging effect (uneven wall thickness distribution) is significantly reduced especially in large-diameter pipes.
The third component contributing to the overall energy savings is the Green Pipe downstream equipment with its "green cooling" system. It operates with energy-efficient, frequency-controlled vacuum and water pumps. This cooling system also operates with a water volume flow cut by almost 90%. This is achieved by pumping the cooling water into the last tank and then passing it on from one tank to the next in the opposite direction to the extrusion process. With the improvements demonstrated, energy cost savings of at least 30% can be achieved.
Further savings can be realized by two additional factors presented by the partner Labotek A/S from Frederikssund, Denmark and the material manufacturer SABIC, domiciled in Riyadh, Saudi Arabia.
Labotek ranks among the leading suppliers of energy-efficient drying systems for the plastics industry. Jointly with battenfeld-cincinnati, the company has developed an EAC variant of its combination dryer, which was shown directly in conjunction with the line. The drying system operates with two separate drying zones. The hot air drawn from the pipe die is blown into the top zone. The bottom zone is laid out as a conventional drying zone with a dry air drying system to ensure the necessary degree of dryness for the material. The dryer on display consumes no more than 11 kW for drying 1,500 kg/h of granulate. By contrast, conventional dryers need 92 kW for the same throughput, which means enormous energy savings in the order of 89%.
SABIC has developed a new PE compound specially designed for energy-efficient pipe extrusion. Vestolen A-Rely 5924 R 10.000 was used to produce the pipe during the Open House demonstration. Compared to a conventional type of PE-100, it requires measurably less energy for melting and processing in an extruder.
Ref. : 201303_Open House_en