Multi Stage Organic Rankine Cycle Using Boil-Off Gas on Liquefied Hydrogen Carrier

In this study, a Reheat Organic Rankine Cycle (ORC) utilizing the cold energy of liquefied hydrogen (LH2) and liquefied natural gas (LNG) was proposed, and its performance was evaluated by comparing it with the base model, which represented a conventional ORC. The process was simulated using ethane and propane, which were considered as potential refrigerants for the target system. A case study was conducted on the inlet pressure and temperature of the turbine included in the process to determine the optimal operating point. The calculation results indicated that ethane exhibited a higher energy efficiency, and a maximum net power of 34.65 kW was obtained when the inlet pressure and temperature of the turbine were 40 bar and 75 °C, respectively. Additionally, an exergy analysis was conducted to quantitatively analyze the high energy efficiency of the Reheat ORC model. We confirmed that exergy efficiency was up to 2.4% higher than that of the base model.