Erema: New Double Disc recycling process proves its worth

At Erema - Engineering Recycling Maschinen und Anlagen Ges.m.b.H. (www.erema.at), the Ansfelden based manufacturer of recycling machines, "Double Disc" refers to the separation of the material preparation processing steps (shredding, mixing, drying, preheating and prehomogenising) from extruder feeding. The Austrian engineering specialists make this possible by integrating a second knife holder disc ("Double Disc") in the patented T-DD cutter/compactor (Picture).

The new process technology, which the company calls 4th Generation Recycling Technology, has already generated keen interest on the market, boasts 15% higher capacity plus at the same time an up to 20% reduction in specific energy consumption. Since its launch at K 2004 last October in Düsseldorf, more than 30 Double Disc systems have already gone into successful operation.

Advert

In addition to the increased capacity and an individually lower energy consumption, further significant benefits have emerged in the first six months of operation at customers´ plants, especially in certain applications:

Reprocessing of materials with high residual moisture
Due to their physical properties, some post consumer materials such as PE film with highstretch (LLDPE) amount, very thin films, fibrous materials etc. are extremely difficult to dry following a washing process using conventional procedures such as drying centrifuges, hot air etc. Trying to go below a residual moisture level from the washing process, which is acceptable for the downstream extrusion process, is an elaborate, costly matter. With Erema´s new Double Disc Technology it is now no trouble to process materials with up to 15% residual moisture in a high-capacity environment. Secondary raw materials with this degree of residual moisture were previously considered unsuitable for direct reprocessing through extrusion. "Despite this, the pellets produced are completely degassed and bubble-free," explains Gerhard Wendelin, Managing Partner of Erema. "The new Erema technology has opened up new, interesting business opportunities in this field."

Reprocessing of pre-shredded, hygroscopic materials
One further area in which the new T-DD technology has become established in a very short time is hygroscopic material waste such as PET film or PA. It has been shown in more than a dozen applications that the viscosity loss (IV) in reprocessing BOPET (bi-oriented PET film) is extremely low – on average around 1% or even less. This result is even more impressive when you consider that when processing with the Double Disc Technology, an extruder without vacuum degassing is used. Doing without extruder degassing supplies two significant benefits: On the one hand, the quality of the recycled pellets is extremely high. "Customers report that the percentage share of repellets that are redirected to the main line is double that of conventional extruders with degassing," says Gerhard Wendelin. "And there is no risk of negative influences on the main line and in the film produced." Wendelin explains that this is due to there being no degassing domes at the extruder. In the degassing domes PET material usually settles which, after a long residence time, may occasionally fall back into the extrusion process, causing quality problems in the film produced. Thanks to the highly effective pre-drying in the Double Disc cutter/compactor, degassing and degassing domes are no longer required.

The effective extruder length can be reduced by about half as a result. A second benefit is the extremely low total energy requirement as a result. “For a typical production capacity of 700 kg/h a conventional BOPET reprocessing step with degassing extruder requires around 245 kW; the new Erema T-DD system needs only 175 kW for the same throughput," explains Wendelin. "With average energy costs this can quickly result in energy savings of €30,000 to €50,000, year after year."

Picture: Process combination PC 1514TVE-DD with melt filter SW 4/170 RTF

Erema - Engineering Recycling Maschinen und Anlagen Ges.m.b.H., Ansfelden/Austria

back to news list