To address the challenges of climate change and energy transition, the "Refinery of the Future," based on alternative feedstocks such as carbon dioxide (Power-to-X), plastic waste, and biomass, is key to the decarbonisation of the petrochemical industry and energy system. Addressing the current research gap in the systematic optimisation of diverse technology portfolios, this paper develops an integrated techno-economic assessment model to quantitatively identify the optimal technology combinations, investment scales, and operational strategies for future refineries, thereby providing decision support for a sustainable industrial transition.
This study constructs a superstructure model that systematically integrates three major technology modules: CO2 electrocatalytic conversion (P2X), biomass thermochemical conversion, and plastic waste chemical recycling. To uniformly evaluate the comprehensive benefits of different products (fuels, chemicals, monomers/polymers), a dual-basis normalisation method based on energy (LHV) and carbon atomic moles is employed. By solving a Mixed-Integer Linear Programming (MILP) model that minimises the total system cost (including operational, investment, and carbon emission costs), this methodology can identify the optimal feedstock mix, technology routes, and operational scales to meet specific market demands, thus providing quantitative support for the system design and investment decisions of future refineries.
To validate the model's practicality, a case study of a one-million-tonne-per-annum (1 Mt/a) future refinery is analysed. Under defined market demand and environmental policy constraints, the optimisation results show that under the baseline scenario, the coupled pathways of biomass gasification with Fischer-Tropsch synthesis and methanol synthesis exhibit the minimum total system cost. The core of this advantage lies in the system's ability to capture CO2 generated during biomass conversion for use in the P2X pathway, achieving carbon cycling and maximising efficiency at the feedstock level. Further investigation reveals that the optimal configuration for a future refinery is not a single technological route but rather a highly integrated system that can flexibly switch in response to key parameters such as electricity prices, product demand, and feedstock availability. This highlights the core value of system flexibility and feedstock diversification.
