Design and optimization of cascade organic Rankine cycle for recovering cryogenic energy from liquefied natural gas using binary working fluid

作者：Kim Kyeongsu; Lee Ung; Kim Changsoo; Han Chonghun^*

来源：Energy, 2015, 88: 304-313.

DOI：10.1016/j.energy.2015.05.047

• ORC
• LNG
• Cascade
• Regasification
• Exergy
• Optimization

A cascade power generation system that utilized the cold exergy of liquefied natural gas (LNG) was proposed in this study. The proposed system adopts binary working fluids for each stage to minimize the exergy destroyed in the condensers of each stage of the cycle. The best combination of working fluids was selected through minimization of the amount of destroyed exergy by varying the flow rate, composition, and pressure of the working fluid. After selecting the working fluids, process optimization was performed through a parametric study. In addition, a sensitivity analysis was performed to observe the effect of temperature variation of the heat sources in the range of 25-85 degrees C on the net power generation.
As a result, the proposed cycle generated 151.78 KJ/h kgLNG under a 25 degrees C heat source and showed an efficiency of 18.64%. The performance of the proposed cycle was linearly increased according to the temperature of heat source. For instance, the proposed system generated 248.79 kJ/h kgLNG, with exergy efficiency of 27.11% under an 85 degrees C heat source.

• 出版日期2015-8