Chemical recycling as the final solution?

 

Today, Belgium is the European leader in recycling household packaging. The maximum retention of raw materials in the cycle, through clean, green technology and CO2 neutrality are central in the pursuit of a circular economy. For glass, metal and paper/cardboard, the recycling process is rarely questioned. However, the recycling of plastics is still in full development. This is especially true for the recycling of new types of plastic packaging, which until recently were not collected, sorted and recycled on a large scale, such as plastic films, trays and bags. For the recycling of household plastic packaging, chemical recycling is therefore increasingly seen as a final solution. However, this is not so straightforward. An overview. 

The what and how of chemical recycling 

In chemical recycling, the chemical structure of plastics is broken down into its original building blocks: from polymers to the simplest hydrocarbons. These can be used to make new plastics, but also products such as chemicals or fuels. Usually, three different chemical recycling techniques are distinguished: 

  • Dissolution / purification: extraction based on solvents, which dissolve the plastic and release the original polymer. This technique is applicable to the pure fraction of PVC, PS and polyolefins. 
  • Depolymerisation: the bond between certain types of polymers is broken by heat to return to the monomer blocks that form the polymer. Used for pure fractions of PET, PA, PLA and PC. 
  • Feedstock recycling or thermochemical degradation, where the plastic is heated in the presence of oxygen (gasification) or without oxygen (pyrolysis): plastic is converted into the different molecules forming hydrocarbon chains. Both techniques focus on mixed plastics. 

Chemical recycling has three major advantages when compared to traditional mechanical recycling: 

  1. Materials can be decolourised. Recycled material can be made completely transparent and colourless through chemical recycling. The recycling of green to colourless transparent bottles, for example, would theoretically be possible in this way. 
  2. Progressive thermal degradation is counteracted. Repeated mechanical recycling corrodes the plastic and breaks the plastic chains, resulting in discolouration or opaque spots. 
  3. Because the material is broken down to the building block, there is no accumulation of contaminants, as could be the case with successive mechanical recycling cycles. In mechanical recycling, this can be prevented by adding additives. 

Because of these advantages, chemical recycling is often promoted as a solution to replace mechanical recycling or to recycle the last percentages1 that currently escape from the chain. Contaminated waste flows or mixed waste flows are also considered. 

The fallacy of chemical recycling 

That is precisely where the fallacy lies. Today, Fost Plus sorts PMD into 14 material flows, including two mixed flows. These are the logical consequence of the high level of purity demanded from the other flows. Certain packaging does not meet these quality requirements or is not recognised by the sorting machines, for example, because consumers put some packages in others. The applications of the recyclate from these mixed flows are still limited today. It is therefore often – wrongly – assumed that these flows would score better in chemical recycling. 

The same applies to packaging made of different materials that cannot be separated. In many cases, these cannot be (mechanically) recycled today. 

Chemical recycling would not remedy these shortcomings. In order to be profitable on a large scale, flows for chemical recycling must also be pure, just like those for mechanical recycling. It will therefore not be possible either to sell contaminated flows or mixed flows. And for pure flows, there is already a mature market today anyway. A mature market that also emits less CO2 and is less cost-intensive. 

Pilot projects and packaging innovation 

Does that mean that Fost Plus does not see a future in chemical recycling? No, not at all. Large-scale chemical recycling is still in its infancy. However, significant investments are required before the technology becomes industrially viable. We strongly believe that chemical recycling will further evolve over the coming years, and can thus offer a valid add-on to mechanical recycling. Numerous pilot projects are currently up and running, which we are closely monitoring and actively supporting. 

In addition, it will continue to be important to bring packaging on the market that is also effectively recyclable, regardless of the technology. Through the eco-modulation inherent to the Green Dot, companies are financially encouraged to choose packaging that is compatible with the existing collection, sorting and recycling system. We therefore support companies with advice on packaging innovation with a view to better recyclability. 

Within the circular economy, our aim is to keep materials in the chain as secondary raw materials for new products or packaging. What role chemical recycling will play in this in the future is not yet certain, but it is a fact that chemical recycling will play a role.