MAS (Maschinen- und Anlagenbau Schulz GmbH of Austria) says its dry cleaning system “is a well-proven alternative to water washing plants for plastic recycling.” Cleaning is carried out by the DRD (Double Rotor Disc) technology that was developed by MAS associate company Ekuma GmbH, also of Austria.
The DRD “is suitable for nearly all kinds of wet and contaminated plastic [including] 100 percent LLDPE stretch film, bale-wrap film, PP-Non-woven, PP-big bags, fishing net or heavily contaminated agricultural film,” according to a news release from MAS and Efactor 3.
MAS also claims that the DRD system “ensures a high degree of impurity separation but operates at approximately 50 percent of the cost of a conventional washing system.”
The DRD combines a cleaning centrifuge and thermal drying in one machine. It also can be installed behind a conventional washing process as a dryer, according to Efactor3.
After pre-shredding, material enters the cylindrical chamber of the DRD from a surge bin in batches. After this automated process, material enters the dryer and is held in suspension by the warm air flowing through the system. “The turbulent flow ensures an excellent drying effect that reduces the moisture content to about two percent,” according to the news release.
Recycling company Reoplast in the Czech Republic processes approximately 2,000 metric tons of PE granulate for film manufactures in Germany, Czech Republic and Austria. The input material used is roughly 80 to 100 percent stretch film. Typical impurities include for tapes, binding stripes, wood and food residuals, as well as sand, dust and soil. The proportion of contaminations is approximately 5 percent and, depending on exposure to inclement weather, the moisture content of the input material is between 10 to 25 percent.
“Before we decided last year to front end the extruder with a DRD system from MAS, we were always having problems with the input material” says Reoplast managing director Irena Oraska.
In January 2007, the DRD was integrated into Reoplast ‘s recycling plant. All material is now pre-cut by a shredder and passes from there into the DRD system. After drying and cleaning the film flakes are transferred directly onto the extruder.
Oraska summarizes the results achieved in the past two years as follows: “The DRD screens out about four cubic meters of impurities every week. Besides increasing the capacity of our re-pelletizing system by 30 percent, we have been able to significantly improve the quality of our products that we were awarded second best supplier from a German film manufacturer. The DRD also helped us to improve our cost structure.”