Rethinking circularity with Re-refineries and supply chains reintegration via multi-objective pareto graph theoretical approach

• Published in: Energy (Oxford) 2023-09, Vol.279, p.127814, Article 127814
• Main Authors: Yeo, Lip Siang, Tiang, Celine Wei Ping, Teng, Sin Yong, Ng, Wendy Pei Qin, Lim, Chun Hsion, Leong, Wei Dong, Lam, Hon Loong, Sunarso, Jaka, How, Bing Shen
• Format: Article
• Language: English
• Subjects: Circular economy; Facility allocation problem; Graph-theoretic; Pareto optimal; Technology selection problem; Waste oil
• ISSN: 0360-5442
• DOI: 10.1016/j.energy.2023.127814

Amidst the global effort in energy transition from fossil fuel remains a challenge for the heavily dependent oil and gas (O&G) industry. Thus, the circular economy (CE) concept offers a viable approach to improve the long-term sustainability of the O&G industry while transitioning toward sustainable development. This research proposed the re-refinery strategies to attain circularity within the O&G industry. Two models are developed to address the strategy decision on both Meso (re-refinery technology decision optimization via P-graph approach) and Macro (supply chain optimization via mixed-integer linear programming (MILP)) perspectives. The re-refining of waste oil utilizing membrane ultrafiltration followed by hydrofinishing is favoured in both cases for its economic potential contributed by its higher production yield (89.94 wt%) compared to distillation (77.12 wt%) pathway. Overall, the re-refining strategy suggest promising improvement in both economic (27.17% lower cost) and environmental (55.35% lower emissions) performance. The addition of in-situ lubricant blending incurred a 4.49% reduction in total cost of the supply chain as compared to the base case with primary reduction (31.48%) in transportation. This study reveals the potential of re-refining approach which serves as guidelines for decision-makers and researchers to strengthen CE practice in modern O&G industry. •Systematic modelling of re-refinery strategy towards oil and gas circularity.•Re-refining technology selection addressed via the novel graph theoretical approach (P-graph).•Sustainable supply chain modeled with Mixed-Integer Linear Programming (MILP) approach.•Economic and environmental gains towards circular economy in Malaysia case study.•Case study of lubricant base oil & commercialized lubricant production are presented.