Periodic Reporting for period 3 - POLYNSPIRE (Demonstration of Innovative Technologies towards a more Efficient and Sustainable Plastic Recycling)
Período documentado: 2021-09-01 hasta 2023-02-28
The overall objective of polynSPIRE has been to demonstrate a comprehensive set of innovative, cost-effective and sustainable solutions, aiming at improving the energy and resource efficiency of the recycling processes for post-consumer (after product’s end of life) and post-industrial (produced during transformation processes from raw materials to final product) plastic containing materials. To this end, three innovation pillars have been demonstrated:
A) Chemical recycling as a path to recover plastic monomers and valuable fillers (such as carbon or glass fibres) relying on microwaves-assisted organic chemistry and smart magnetic catalysts.
B) Advanced additivation for mechanical recycling processes to enhance recycled plastics quality, using vitrimers, high-energy radiation and compatibilizing additives.
C) Valorisation of plastic waste as carbon source in electric arc furnaces (EAF) for the steel industry.
The degree of demonstration has been different for the three different types of innovations: the project achieved TRL7 that level in the framework of the steel sector where between 25-50% of fossil coal was replaced by plastic product, and in the improvement of properties of mechanical recycling product, where recycling test using industrial plastic injectors were implemented. In the case of chemical recycling developments, polynSPIRE project worked within TRL5-6 for this innovation. For chemical recycling assisted by MW heating, an intermediate reactor was built and tested, and trials were performed (TRL6). In the case of innovation assisted by SMM, TRL5 has been the operational environment of work, where progresses were made in understanding the catalytic activity in the relevant depolymerizations, developed process and proved it on the lab scale, and the design of the equipment suitable for large scale was made.
• Improvement of chemical reactions of PA and PU depolymerization assisted by MW. An intermediate scale of MW reactor has been configured and installed, and specific simulations of the MW heating process have been completed to assess the power needs of an industrial recycling process. Designs of industrial reactor have been developed. Material and safety requirements and know-how for future industrial scale have been generated.
• Processes for chemical recycling of PU and PA assisted by SMM have been developed. Progresses have been made in understanding the catalytic activity in the relevant depolymerization processes, and were proven on the lab scale with post-industrial waste feedstock. These application tests provided useful guidance on how to further develop this technology. In addition, the final detailed engineering of the pilot plant has been completed.
• Mechanical recycling processes have also been validated in the project. Specifically, advance mechanical recycling processes, and use of vitrimers to recycle PU foams through the application of standard plastic processing technologies. Validation at semi-industrial level of gamma rays as an external energy source for the generation of crosslinking and the implementation of gamma rays treated materials in injection moulding has been achieved as well, and development of an industrial methodology for the application of gamma rays in plastic materials.
• PolynSPIRE has also contributed to validate the use of plastic residues as a carbon substitute in the steel manufacture process. Plastic grains have been studied for this application, where a new injector in an Electric Air Furnace has been designed and commissioned, and real industrial scale tests have proven successful substitution of 30% of coal in every operation.
As transversal activities developed to evaluate the project results, LCA and LCC methodologies were created and applied to evaluate the impact of each technology developed. Also, and exploration of the data collected for the recycling processes was conducted and different machine learning models were trained to estimate the environmental impacts depending on the selected operating conditions.
By last, in order to maximize the project impact, a market analysis has been developed in polynSPIRE for technologies and results, exploitation road for the KERs, and Business Plans. Also, very good results have been obtained in terms of dissemination: since Oct, 2018, polynSPIRE was present in 34 conferences, 14 internal events, 13 scientific and online publications and 25 lectures and seminars. These, together with the 11 project videos produced, and the activity in social media, has reached an impact of approximately 10,200 persons reached from the scientific community, 870 industry representatives and 12,600 from general public.
• In Mw-assisted recycling process of PA66, the use of recycled monomers reduces the impact of PA66 manufacturing (between 3,1 to 3,5 t CO2 eq/t PA66 and between 0,2 to 0,3 t oil eq/t PA66). CO2 emissions are reduced between 57% to 69%, and fossil resources between 10% to 30%.
• Mechanical recycling of PA6 through gamma irradiation could reduce the CO2 emissions around 43% (3,4 t CO2 eq/t PA6) and fossil resources around 72% (2,7 t oil eq/t PA6).
Regarding polyurethane value chain, the hypothetical scaled-up processes would also reduce the environmental impacts compared to virgin polyurethane foams.
• Polyols obtained through chemical recycling of PUF (both MW and SMM), are less pollutant than virgin polyols. The use of recycled polyols reduces the CO2 emissions of PUF manufacturing between 11% to 19% (0,6 to 1,0 t CO2 eq/t PUF) and fossil fuels between 10% to 30% (0,3 to 0,6 t oil eq/t PUF).
• Mechanical recycling of PUF (vitrimers) could reduce the CO2 emissions around 84% (4,6 t CO2 eq/t PUF) and fossil resources around 89% (1,7 t oil eq/t PUF).
Regarding valorisation in steel industry, the partial substitution of hard coal by plastic grains allows the reduction of the impacts of the steel manufacturing process:
• Reduction of at least 30% of fossil carbon sources.
• Reduction of CO2 equivalent emissions: around 7 kg CO2 eq/t steel.
• Reduction of fossil resources: around 2,4 kg oil eq/t steel.