Chemical recycling: the supreme discipline for the Circular Economy in the plastics industry?

Introduction to chemical recycling at SÜDPACK

Mr Hardow, how does chemical recycling work?

Dirk Hardow: In chemical recycling, used plastics are converted into pyrolysis oil in a high-temperature process under exclusion of oxygen. This oil can be used for the production of plastics and thus replaces conventional crude oil. In our case, we use it to produce high-performance films for packaging products with high quality and hygiene requirements, such as food and pharmaceuticals.

For which materials is the process suitable?

Hardow: Compared to mechanical recycling, chemical recycling offers significantly more possibilities, especially to recycle contaminated, mixed or other plastic fractions that cannot be recycled mechanically in a sustainable way. Furthermore, the process is also suitable for recycling highly complex multi-layer films made of different plastics. These are used, among other things, in the food industry for packaging a wide variety of products such as meat and sausage products, cheese, fish, bakery products, etc. The company has also invested in a special technology for the recycling of plastic films.

You are specifically investing in a special chemical recycling technology. What exactly is this about?

Hardow: This is an advanced thermo-chemical process for the liquefaction of solid hydrocarbons in a one-step process, also known as direct oiling. The recycling plants of our cooperation partner in Ennigerloh, Münsterland, are approved for fully continuous operation and have been certified according to the sustainability criteria of ISCC-Plus since March 2021.

Overall, we consider chemical recycling and specifically our process to be an important, complementary building block for a circular economy in the plastics industry. And this is always the case when mechanical recycling reaches its limits despite far-reaching Design for Circularity.

Exhibitors & products around recycling

• Recycling plants
• Separating and sorting systems for waste
• Size reduction equipment (crushers, shredders, grinders)
• Compounding lines
• Recyclates

What is special about your process – compared to other chemical recycling processes?

Hardow: From our point of view, it is currently the only process that leaves many of the much-discussed disadvantages of chemical recycling far behind – and thus has real potential for the future.

What our technology has in common with known gasification or pyrolysis processes is that solid organic input materials (plastics and biomass) are converted into oils and gases by splitting (cracking) the hydrocarbon chains. However, the process differs significantly in its flexibility with regard to feedstocks, which do not necessarily have to be of polyolefin origin. Thanks to this high feedstock tolerance, our solution is suitable for all the types of plastics already mentioned that cannot be mechanically recycled up to now. This means that there are significantly more possibilities, as the technology is aimed at recovering the recyclable components through thermal decomposition. In addition, the plastic waste does not have to be sorted elaborately in advance. But of course it is clear that the more homogeneous the waste stream, the higher the yield.

The process is also more sustainable overall. In what way?

Hardow: The process takes place at a lower temperature of less than 400°C. This eliminates coking. This eliminates coking and no toxic pyrolysis gases are formed. The low temperature, the single-stage nature of the process and the introduction of energy directly into the material via friction enable the material to be converted with relatively little energy input.

Moreover, chemical recycling always delivers the same, high-quality output – in contrast to mechanical recycling. With mechanical recycling, the challenge is often to achieve the same level of quality in the long term, as fluctuations in the composition of the infeed material cannot always be ruled out.

What about the quality of the new secondary raw material marketed under the name CLR, or Circular Liquid Resource?

Hardow: The liquid resource resembles fossil petroleum or the products derived from it in many essential properties. It can therefore be processed as a fully-fledged substitute for fossil resources in existing refinery/petrochemical plants, is miscible with fossil oils and can be stored just like them. Strictly speaking, we keep the universal resource hydrocarbon in circulation. This is an extremely important aspect – and a completely new dimension in terms of Circular Economy.

Advantages of chemical recycling compared to mechanical recycling

Mechanical recycling in particular is becoming increasingly important. How do you assess this circumstance in view of the current situation?

Hardow: Mechanical recycling is an important component of the Circular Economy, no question. But in order to close loops, especially in the area of food packaging, we need a real technology mix. Because mechanical recycling is reaching its limits, as already described: The quality of the materials and also the possible uses of the recyclable materials obtained in this way are constantly decreasing – downcycling is simply not repeatable at will. In addition, the scope for the use of mechanically obtained recyclates in our industry is still very small – and in the area of food packaging it is currently only permitted for PET flakes.

Apart from that, the packaging industry does not have sufficient volumes of recyclates available to meet the planned legal requirements of the PPWR (Packaging and Packaging Waste Regulation), provided that one focuses exclusively on mechanical recycling. With the existing infrastructure, we definitely cannot recycle sufficient volumes of plastics in the foreseeable future either. This is also a central argument that we are currently discussing with market partners, associations and political representatives in connection with the introduction of the regulation and where we see, among other things, a considerable need for optimisation. Because it is not enough to pass a sensible law – the prerequisites for investments and capacity expansions must be created, terminology defined, framework conditions clarified and targets attainable. From SÜDPACK's point of view, there is still a lot to do here.

Elena Blume (Editorial team K-Mag)