Decarbonising the packaging plastic industry requires a disruptive change in both our production and consumption habits. Bioplastics produced from non-edible lignocellulosic biomass will become the backbone of a circular plastic economy. However, current processes retrofitting biobased molecules to petrochemicals result in high process complexity and low biomass utilisation efficiency (BUE), therefore hindering economic competitiveness and absolute sustainability due to increased tensions on water and land resources [1], [2]. Alternative bioplastics with similar properties to PET, the main packaging plastic, but retaining as much biogenic atoms as possible in native-like structures have recently been developed to address this problem [3].
In this study, trade-offs between traditional retrofitting pathways and those novel technologies, with improved process efficiency albeit lower drop-in readiness levels, are compared on several levels of modelling complexity to assess their large-scale viability.
Inherent mass and energy losses are identified at an early-stage using the Second-law Thermodynamic Analysis and complemented with detailed process modelling, techno-economic assessment and life-cycle analysis of four chemo-catalytic processing routes: (1) PET via methanol obtained from biomass gasification, (2) PET via 5-chlromethylfurural (CMF) [4], (3) PEF (polyethylene furanoate) via CMF and (4) PHX (polyhexylene xylosediglyoxylate), a new polymer recently engineered by our group [5]. The latter is characterised by high BUE (97%) and chemical exergy efficiency, which results in lower manufacturing costs and CO2 emissions, achieved through aldehyde functionalisation. The additional chemicals represent the main environmental burden which could be further reduced by producing them from CO2 or biomass.
To systematically investigate such symbiotic relationships within the chemical industry, we developed a superstructure proposing decarbonised production pathways for all major reagents around the processes of interest. Through multi-objective optimisation for cost and carbon footprint minimisation, progressively self-sufficient biorefinery configurations are generated. As options with the lowest abatement costs are selected first, our methodology helps decision makers prioritise efforts towards the decarbonation of the whole plastic production supply chain while realising the best use of the biomass resource.
References
[1] M. Bachmann et al., “Towards circular plastics within planetary boundaries,” Nat Sustain, vol. 6, no. 5, Art. no. 5, May 2023, doi: 10.1038/s41893-022-01054-9.
[2] P. Gabrielli et al., “Net-zero emissions chemical industry in a world of limited resources,” One Earth, May 2023, doi: 10.1016/j.oneear.2023.05.006.
[3] L. P. Manker, M. J. Jones, S. Bertella, J. Behaghel de Bueren, and J. S. Luterbacher, “Current strategies for industrial plastic production from non-edible biomass,” Current Opinion in Green and Sustainable Chemistry, vol. 41, p. 100780, Jun. 2023, doi: 10.1016/j.cogsc.2023.100780.
[4] M. Mascal, “5-(Chloromethyl)furfural (CMF): A Platform for Transforming Cellulose into Commercial Products,” ACS Sustainable Chem. Eng., vol. 7, no. 6, pp. 5588–5601, Mar. 2019, doi: 10.1021/acssuschemeng.8b06553.
[5] L. P. Manker et al., “Sustainable polyesters via direct functionalization of lignocellulosic sugars,” Nat. Chem., vol. 14, no. 9, Art. no. 9, Sep. 2022, doi: 10.1038/s41557-022-00974-5.
