Decarbonizing petrochemical refineries using integration with small modular reactors – A thermodynamics and environmental analysis

This paper investigates the integration of Small Modular nuclear Reactors (SMR) into petrochemical refineries to address the sector’s high thermal energy demands and environmental impact. A detailed thermodynamic model is developed for a refinery processing 150,000 barrels of crude oil per day, considering three configurations: conventional without integration of SMR, partially nuclear-assisted, and fully assisted. The proposed system combines a steam Rankine cycle with SMRs supplying superheated steam at 7 MPa and 600°C. Nuclear-derived steam is extracted at multiple temperature levels (100°C, 180°C, and 460°C) to energize refinery units below 450°C according to the demand. Thermodynamic analysis using mass, energy, and entropy balances demonstrates that up to 595 MW of thermal energy from SMRs can be directly supplied to refinery processes, and an additional 1465 MW can be used for air preheating, totaling 2060 MW—approximately 40% of the total refinery thermal load (5203 MW). The integration yields about 28% electrical efficiency and about 66% cogeneration efficiency, based on the tabulated duties. Exergy destruction is dominated by air preheaters (≈41%), followed by high-temperature reactors (≈24%) and combustors (≈15%); the steam generator contributes ≈10%, while the rest of the Rankine block is a smaller share (≈6%), with turbomachinery itself ≈2%. Carbon dioxide emissions are significantly reduced from 9375 tonnes/day (conventional) to 1550 tonnes/day in the full nuclear-assisted case—a reduction of nearly 83.5%. Parametric studies reveal trade-offs between cogeneration and power efficiency, with optimal performance achieved at moderate cogeneration levels. This study confirms the viability of SMR integration for refinery decarbonization. Drawing on lessons from solar-assisted systems, it also proposes thermal synergy strategies adaptable to both renewable and nuclear heat sources. The findings position nuclear-assisted refining as a scalable, resilient, and low-carbon solution for the future of industrial energy systems.