Liquefied natural gas (LNG) is rich in cold energy. Recovering cold energy from its different temperature zones can reduce conventional energy consumption, promote sustainable energy utilization, and lower pollution emissions, making it a promising method to enhance thermodynamic efficiency. Hydrogen, as a clean and efficient energy carrier, can decrease reliance on fossil fuels, alleviate energy shortages, and facilitate the achievement of global carbon neutrality goals, serving as a crucial solution to address the energy crisis. Introducing hydrogen from port areas into LNG terminals for mixed gas output can expand market potential and improve profitability. Aiming at the core problems in current research, including the insufficient integration of LNG cryogenic energy cascade utilization and hydrogen technology, poor system flexibility and adaptability, and the lack of a comprehensive life cycle evaluation system, this study constructs an innovative LNG + H₂ self-sustaining cryogenic energy cascade system (LNG-H₂-ORC-SWRO-CS).This system achieves multi-functional utilization including LNG vaporization, cold energy power generation, seawater desalination, multi-stage cold storage, mixed gas output, and CO2 capture from flue gas. The generated freshwater is recycled into the system, while electricity powers the cold storage system, forming an energy closed loop to enhance the efficiency of cryogenic energy utilization. The study first conducts thermodynamic system analysis to calculate various performance indicators: The system generates 1,445.51 kW (411.01 TR) of cooling capacity with an ηen efficiency of 72.08% and ηex efficiency of 88.61%, achieving a specific heat capacity (cp) of $85.23 /GJ and a specific power output (bp) of 1.339 × 10− 2 mpt/kJ. Via the optimization of the three - stage Organic Rankine Cycle (ORC) system and the analysis of carbon footprint, the study achieves the dual benefits of a net power generation saving of 1,716.67 kW and an annual CO₂ emission reduction of 12.25 kilotons for the first time. Subsequently, 3D modeling analysis of system parameters clarifies the coordinated variation patterns and trends of key parameters. Finally, the three-dimensional Animated Oat Optimization (AOO) algorithm is adopted for multi-objective optimization of the system, achieving significant performance improvements: the exergy efficiency (ηex) increases to 89.67%, the specific exergoeconomic cost (cp) decreases to $55.17/GJ, and the specific exergoenvironmental impact (bp) reaches 1.362 × 10⁻² mpt/kJ. The cascade utilization system constructed in this study provides a novel technical paradigm for the synergistic coupling of LNG cryogenic energy and hydrogen energy, and its optimization methods and the revealed variation laws of key parameters offer solid theoretical support and practical guidance for the optimal design of relevant industrial engineering.

Towards carbon-neutral energy systems: synergistic cascade recovery of LNG cryogenic energy and hydrogen blending for enhanced efficiency and environmental performance

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发表日期：

2026年6月25日

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Rui Yu,
Zhen Pan,
Liyan Shang,
Jingxian Yu,
Zhien Zhang

摘要

Liquefied natural gas (LNG) is rich in cold energy. Recovering cold energy from its different temperature zones can reduce conventional energy consumption, promote sustainable energy utilization, and lower pollution emissions, making it a promising method to enhance thermodynamic efficiency. Hydrogen, as a clean and efficient energy carrier, can decrease reliance on fossil fuels, alleviate energy shortages, and facilitate the achievement of global carbon neutrality goals, serving as a crucial solution to address the energy crisis. Introducing hydrogen from port areas into LNG terminals for mixed gas output can expand market potential and improve profitability. Aiming at the core problems in current research, including the insufficient integration of LNG cryogenic energy cascade utilization and hydrogen technology, poor system flexibility and adaptability, and the lack of a comprehensive life cycle evaluation system, this study constructs an innovative LNG + H₂ self-sustaining cryogenic energy cascade system (LNG-H₂-ORC-SWRO-CS).This system achieves multi-functional utilization including LNG vaporization, cold energy power generation, seawater desalination, multi-stage cold storage, mixed gas output, and CO₂ capture from flue gas. The generated freshwater is recycled into the system, while electricity powers the cold storage system, forming an energy closed loop to enhance the efficiency of cryogenic energy utilization. The study first conducts thermodynamic system analysis to calculate various performance indicators: The system generates 1,445.51 kW (411.01 TR) of cooling capacity with an η_en efficiency of 72.08% and η_ex efficiency of 88.61%, achieving a specific heat capacity (c_p) of $85.23 /GJ and a specific power output (b_p) of 1.339 × 10^− 2 mpt/kJ. Via the optimization of the three - stage Organic Rankine Cycle (ORC) system and the analysis of carbon footprint, the study achieves the dual benefits of a net power generation saving of 1,716.67 kW and an annual CO₂ emission reduction of 12.25 kilotons for the first time. Subsequently, 3D modeling analysis of system parameters clarifies the coordinated variation patterns and trends of key parameters. Finally, the three-dimensional Animated Oat Optimization (AOO) algorithm is adopted for multi-objective optimization of the system, achieving significant performance improvements: the exergy efficiency (η_ex) increases to 89.67%, the specific exergoeconomic cost (c_p) decreases to $55.17/GJ, and the specific exergoenvironmental impact (b_p) reaches 1.362 × 10⁻² mpt/kJ. The cascade utilization system constructed in this study provides a novel technical paradigm for the synergistic coupling of LNG cryogenic energy and hydrogen energy, and its optimization methods and the revealed variation laws of key parameters offer solid theoretical support and practical guidance for the optimal design of relevant industrial engineering.