Investigation on Energy and Exergy Performance of a Hydrogen Liquefaction Cycle Employs LNG and Improved Joule-Brayton Cycle

The use of hydrogen as a clean fuel has gained the attention of many scientists due to the energy issues and environmental pollution caused by fossil fuels. A key requirement for expanding hydrogen use is the investigation and thermodynamic analysis of the liquefaction cycle, which includes examining various hydrogen liquefaction cycles during pre-cooling and cryogenic cooling. Analyzed cycle is a liquefaction process that utilizes advanced cascade Joule-Brayton (J-B) refrigeration cycles and a dual-pressure organic Rankine cycle, assisted by LNG regasification. Simulations and analyses were conducted using Aspen HYSYS V12. The results showed that in cycle, over 50% of the input exergy is lost during the cryogenic cooling stage. The value of SEC, COP and EXE cycle is 6.618 kWh/kgLH2, 0.19884 and 45.797% respectively. The net output power of Rankine cycle is 458.82 kW, which can be used to feed other parts of the hydrogen liquefaction process. Also, the results showed that in the pre-cooling process, the amount of useful exergy is 61.21%, which uses 22.73% of the input exergy in a superior way compared to the existing cycles.