Selective Plastic Extraction

The purest form of Plastic-to-Plastic for Polyethylene (PE) and Polypropylene (PP)”

Selective Plastic Extraction (SPE) is an innovative and advanced chemical plastic recycling technology that can convert a mix of waste plastics into near virgin PE & PP materials. OBBOTEC provides a unique solution for the ever-growing worldwide plastic waste problem and the circularity of plastics. The SPE process of OBBOTEC classifies between Mechanical and Chemical recycling to monomers and therefore we name it an advanced form of chemical recycling, while polymers chains remain intact and are not broken down, as with chemical recycling to monomers. In fact, Plastics-to-Plastics in the purest form, which puts SPE higher on the Lansink Hierarchy.

 

Nowadays there are several chemical recycling technologies in the market for mono-streams, such as for example polyethylene terephthalate (PET) and polystyrene (PS). However, a key challenge is the valorisation of the largest flow of mixed difficult to non-recyclable PE and PP. This often concerns far from mono-streams and often has a heterogeneous composition. This flow comprises the residual fractions that remain after separating the recyclable fractions. This means that it is not a single type of plastic, but mixtures of multiple plastics. Flows comprising mixed plastics fractions from residues are more abundant than mono-streams and a process that can handle them poses a great advantage. Beside this, it relates to more than 70% of the plastic waste and therefore has a major impact in solving the plastic recycling problem. Selective Plastic Extraction focuses on this mixed waste stream and also contaminated mono-streams of PE and PP.

Selective Plastic Extraction is an Advanced Chemical Recycling process that accomplishes a separation of mixtures of different plastics to virgin PE, PP or PE/PP granules using specific solvents. The in size most important types of PE and PP are separated from the other types and stripped of additives and contaminants. With this type of chemical recycling plastic is not depolymerized, but the polymer chains are retained, so that PE and PP are directly produced to near virgin quality. After addition of additives, as a directly marketable granulate. In such a single recycling process to high-quality virgin granulate, there is a large degree of valorisation with a very sound economic value. As mentioned above, these Plastics-to-Plastics purest form. From the viewpoint of an LCA / chain analysis, such a process will therefore score better and be less dependent on existing manufacturers who currently produces the plastic from conventional monomers. At moderate energy- and raw material consumption, this means a very good score in a Life Cycle Analysis, especially when there is multiple recycling (MLCA).

The Proces

A residual flow of plastics is first brought into contact with a specific solvent. Here the PE/PP olefin polymers are selectively dissolved, after which it is drained from the reaction vessel. After evaporation of the solvent, the polymer precipitates, after which it is purified in a few washing steps, whereby dyes (e.g. cadmium) and plasticizers are removed. The pure form of PE/PP obtained can be brought back to specifications with new additives and sold as near virgin PE / PP granulate.