Techno‐economic assessment and comparison of different plastic recycling pathways: A German case study

Rebekka Volk,Dieter Stapf,Frank Schultmann,Christoph Stallkamp,Richard C Müller,Justus J Steins,Savina Padumane Yogish

doi:10.1111/jiec.13145

Rebekka Volk, Dieter Stapf + Show 5 more

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https://doi.org/10.1111/jiec.13145

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Abstract

Greenhouse gas (GHG) emissions need to be reduced to limit global warming. Plastic production requires carbon raw materials and energy that are associated today with predominantly fossil raw materials and fossil GHG emissions. Worldwide, the plastic demand is increasing annually by 4%. Recycling technologies can help save or reduce GHG emissions, but they require comparative assessment. Thus, we assess mechanical recycling, chemical recycling by means of pyrolysis and a consecutive, complementary combination of both concerning Global Warming Potential (GWP) [CO2e], Cumulative Energy Demand (CED) [MJ/kg], carbon efficiency [%], and product costs [€] in a process‐oriented approach and within defined system boundaries. The developed techno‐economic and environmental assessment approach is demonstrated in a case study on recycling of separately collected mixed lightweight packaging (LWP) waste in Germany. In the recycling paths, the bulk materials polypropylene (PP), polyethylene (PE), polyvinylchloride (PVC), and polystyrene (PS) are assessed. The combined mechanical and chemical recycling (pyrolysis) of LWP waste shows considerable saving potentials in GWP (0.48 kg CO2e/kg input), CED (13.32 MJ/kg input), and cost (0.14 €/kg input) and a 16% higher carbon efficiency compared to the baseline scenario with state‐of‐the‐art mechanical recycling in Germany. This leads to a combined recycling potential between 2.5 and 2.8 million metric tons/year that could keep between 0.8 and 2 million metric tons/year additionally in the (circular) economy instead of incinerating them. This would be sufficient to reach both EU and German recycling rate targets (EC 2018). This article met the requirements for a gold‐silver JIE data openness badge described at http://jie.click/badges.

Highlights

Plastic production requires predominantly crude oil and energy while emitting Greenhouse gas (GHG) emissions that need to be reduced to combat climate change (IPCC, 2013)
This study develops a method to assess primary plastics production, post-consumer plastic packaging waste sorting (Section 2.2.1), and recycling (Section 2.3) concerning costs, carbon efficiency, cumulative energy demand (CED), and global warming potential (GWP) (Section 2.4) for polyethylene (PE), polypropylene (PP), polyvinylchloride (PVC), and general purpose polystyrene (GPPS)
10 Pyrolysis inputs differ in chemical recycling (RDF) and combined recycling

Summary

Introduction

Plastic production requires predominantly crude oil and energy while emitting GHG emissions that need to be reduced to combat climate change (IPCC, 2013). The German chemical sector, the largest in Europe, accounts for 6% of annual GHG emissions (UBA, 2018a; Destatis, 2018; VCI, 2019; Wyns et al, 2018). In Europe, 49 million tons of plastics are produced annually for packaging (40%), construction (20%), automotive parts (9%) and electronics (6%). 25.8 million tons of plastic waste are generated annually (EC, 2018). Plastic waste can be recycled mechanically or chemically, or processed to chemical or physical energy carriers. In Germany, 46 wt% of the plastic waste (including production and processing wastes) is recycled mechanically; 1 wt% is recycled chemically (Conversio, 2018)

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