(578d) A Probabilistic Approach to Assessing the Economic and Environmental Viability of Poly-Crude Manufacturing from Plastic Waste.

Plastic waste recycling technologies continue to face significant challenges in matching the energy, economic, and environmental efficiencies of well-established petroleum refining processes¹. To address these challenges, we propose a novel pathway in which plastic waste is converted into a refinery-compatible feedstock, termed ‘poly-crude’, via hydrocracking. This approach enables the reintegration of plastic waste into the existing petroleum supply chain, allowing final refining in existing infrastructure, thus offering potential capital cost and carbon savings.

To evaluate the feasibility of this approach, we present a probabilistic sustainability assessment of poly-crude manufacturing at the early stages of technological development. Rather than definitive, static, and passive process evaluations, which can be incomprehensive for understanding early-stage technologies, we instead assess the probability of the process becoming feasible. This shift enables a more realistic evaluation by capturing the full range of possible outcomes, accounting for the uncertainty inherent in emerging technologies². We performed an integrated techno-economic analysis (TEA) and life cycle assessment (LCA) to assess financial viability and environmental performance, identify key sustainability drivers, and understand trade-offs across multiple dimensions of sustainability. .

Our techno-economic analysis results indicate that the probability of poly-crude manufacturing becoming economically feasible ranges from 6% to 24%, depending on hydrogen-handling conditions. The main cost drivers are the reactor and hydrogen storage capital cost, which together account for approximately 30% of the total manufacturing costs. In parallel, preliminary LCA results for the base-case scenario reveal that hydrogen demand, electricity, and heating utilities, particularly from the reaction and separation processing areas, are the primary contributors to GHG emissions. These findings highlight the strong sensitivity of the process’s sustainability to reaction conditions, such as temperature and pressure, and hydrogen demand. Specifically, lowering reaction temperatures can reduce heating utilities requirements, thereby decreasing associated GHG emissions. Similarly, operating at lower pressure can lead to the use of less expensive reactors due to reduced wall thickness requirement, resulting in lower capital expenditures. Additionally, minimizing hydrogen consumption by keeping high selectivity towards ‘poly-crude’ can further improve sustainability by lowering both hydrogen storage costs and GHG emissions associated with hydrogen. Building on these insights, we developed a Python-based framework that integrates techno-economic and life cycle analysis to link reaction performance indicators with sustainability metrics. This agile tool enables probabilistic evaluation and rapid scenario simulation to inform research and design decisions aimed at advancing sustainable poly-crude manufacturing. This open-source module can be used by a broader community, providing a quick approach to assess trade-offs.

References:

(1) Forman, G. S.; Divita, V. B.; Han, J.; Cai, H.; Elgowainy, A.; Wang, M. U.S. Refinery Efficiency: Impacts Analysis and Implications for Fuel Carbon Policy Implementation. Environ. Sci. Technol. 2014, 48 (13), 7625–7633. https://doi.org/10.1021/es501035a.

(2) Li, Y.; Trimmer, J. T.; Hand, S.; Zhang, X.; Chambers, K. G.; Lohman, H. A. C.; Shi, R.; Byrne, D. M.; Cook, S. M.; Guest, J. S. Quantitative Sustainable Design (QSD) for the Prioritization of Research, Development, and Deployment of Technologies: A Tutorial and Review. Environ. Sci.: Water Res. Technol. 2022, 8 (11), 2439–2465. https://doi.org/10.1039/D2EW00431C.