Potential of chemical recyclingto improve the recycling of plastic waste

Abstract: Chemical recycling can improve the plastic recycling rates and reduce the level of CO2 from fossil plasticsproduction. Thus, it is seen as an attractive technology in the action towards meeting the emission, circulareconomy and recycling targets. In the Swedish context, it could help reach the carbon neutrality goal by2045. This thesis aims to investigate the potential of chemical recycling in the Swedish plastic recyclingsystem with Brista waste-to-energy plant in Stockholm as a case study. The thesis describes different stagesof current Swedish plastic recycling system and quantifies material losses at every stage. The recycling rateof plastic packaging in the household waste stream in Stockholm was found to be lower than 7%.Remaining 93% is sent for energy recovery through incineration. The feasibility of implementing differentchemical recycling technologies is analysed together with the Technology Readiness Level (TRL). Theresults showed that there are three technologies with the highest TRL of 9: thermal cracking (pyrolysis),catalytic cracking and conventional gasification. The important parameters when implementing chemicalrecycling in an existing facility are discussed and used for the feasibility analysis of implementing thesethree technologies in Brista facility. It is not obvious which technology is the best one for this application.Gasification is proven for the production of intermediates (oil or syngas) which can be used for newplastic production, however, the scale of Brista facility is not large enough for a gasification plant to befeasible. Pyrolysis and catalytic cracking could be used at a smaller scale, but they have not contributed tothe production of new plastics so far, thus, both technologies would require further research and tests ona pilot scale before moving to commercial operation. The findings from this study have to be followed byan in-depth analysis of real data, from pilot or commercial projects, which is currently unavailable.The major challenges to implement chemical recycling of waste plastics in Sweden are of economic andpolitical nature. The key point in successful deployment of chemical recycling is the development ofa business model which would ensure that all actors along the plastic recycling chain benefit economicallyfrom the solution. For the Brista 2 plant case, the challenges include Stockholm Exergi’s insufficientexpertise to perform chemical recycling independently, uncertain feedstock purity requirements andchallenging market situation.