Abstract
This dissertation systematically investigates pathways for domestic refineries to achieve net-zero carbon emissions, supporting the national targets of carbon peaking by 2030 and carbon neutrality by 2060. An integrated Life Cycle Assessment (LCA) with the Long range Energy Alternatives Planning (LEAP) framework is developed to quantify carbon footprints, evaluate mitigation strategies, and project long-term transition pathways. To enhance the robustness of future mitigation assessments, uncertainty propagation analysis is incorporated by considering variability in activity levels, emission factors, electricity grid decarbonization trajectories, technology efficiencies, hydrogen production carbon intensities, and CCUS capture performance. Consequently, mitigation outcomes are reported as uncertainty ranges rather than single-point estimates, providing a more comprehensive representation of future decarbonization potential.The carbon footprint baseline analysis shows that processing one ton of crude oil in 2025 generates approximately 239.9 kg CO₂-eq from energy perspective. Fuel gas consumption is identified as the dominant emission source, contributing 44.2% of total emissions. Subsequently, five carbon allocation strategies for refined products are quantitatively evaluated and compared. Results demonstrated that allocation based on the mass flow rate of product streams is the most suitable approach. Under this method, the carbon label for Liquefied Petroleum Gas (LPG) exhibits the highest product carbon intensity among major refinery products. By integrating analyses of energy efficiency, fuel specifications, and greenhouse gas intensity, this research establishes a scalable carbon-labelling framework that supports transparent carbon disclosure and product-level decarbonization management.
To decarbonize refinery energy systems, a phased electrification roadmap is developed based on process temperature requirements and projected grid decarbonization trajectories. For low-temperature processes ( <160° C), utilizing industrial heat pumps can immediately reduce energy consumption by 39.2%, with potential carbon reductions of 89.6% as the grid decarbonizes. In contrast, medium temperature retrofits (160–300°C) using electrode boilers are currently constrained by grid emissions; analysis shows that immediate substitution for 1.0 MPa and 3.5 MPa boilers would increase emissions by 66.6% and 39.3%, respectively. Therefore, medium-temperature electrification is recommended post-2035, when the grid emission factor drops below 0.4078 kg CO₂/kWh. For high-temperature furnaces, the shift to E-furnaces is projected for 2049, corresponding to a grid emission factor of 0.2389 kg/kWh. These findings provide a technology-specific deployment roadmap for refinery electrification decarbonization scenarios.
The study further evaluates multiple hydrogen production pathways spanning conventional fossil-based, renewable-based, and carbon negative technologies. Results indicate that grid-powered alkaline water electrolysis currently exhibits a carbon intensity of 31.8 kg CO₂/kg H₂, exceeding that of coal-gasification-based hydrogen production due to the carbon intensity of the electricity supply. In contrast, biomass gasification integrated with carbon capture and storage (BECCS) achieves substantial net-negative emissions. Among the biomass feedstocks investigated, rice-straw-based hydrogen production coupled with CCS delivers the best environmental performance, removing up to 16.2 kg of CO₂ per kg of hydrogen produced. Therefore, biomass-derived hydrogen integrated with CCS is identified as the most effective long-term hydrogen decarbonization strategy for refineries.
Scenario analysis using the integrated LCA–LEAP framework demonstrates that incremental improvements alone are insufficient to achieve carbon neutrality. A radical transition scenario characterized by large-scale deployment of biomass-based hydrogen production, extensive CCUS implementation, and progressive electrification enables the refinery sector to achieve net zero emissions by 2056. This pathway relies heavily on substituting fossil fuels with bio-hydrogen and CCUS. It finds that while electrification is a necessary component, its effectiveness is contingent upon the grid emission factor dropping below 0.2291 kg CO₂-eq/kWh. Notably, CCUS emerges as the dominant mitigation strategy, responsible for a 65.4% reduction in total emissions. The findings underscore the indispensability of BECCS as a negative carbon technology for achieving net-zero carbon emissions for the oil refining sector. Uncertainty analysis indicates that although the timing of net-zero achievement may vary under different technological and policy assumptions, the dominance of BECCS and CCUS remains robust across all scenarios.
Overall, this dissertation provides a comprehensive methodological framework and strategic roadmap for refinery decarbonization, highlighting the critical role of negative-emission technologies in achieving net-zero transitions within carbon-intensive industrial sectors. Methodologically, this work represents one of the first studies to integrate product-level carbon labeling, refinery electrification planning, hydrogen pathway optimization, uncertainty propagation analysis, and long-term net-zero transition modeling within a unified LCA–LEAP framework for the refining industry.
| Date of Award | 15 Nov 2026 |
|---|---|
| Original language | English |
| Awarding Institution |
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| Supervisor | Tao Wu (Supervisor), Xiang Luo (Supervisor) & Hao Liu (Supervisor) |
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