A Novel Two-Stage Ethylene Rankine Power Cycle with Cold Energy Recovery of LNG

Abstract

A novel two-stage ethylene Rankine power cycle that can recover cold energy of LNG is represented. A core device of multi-stream cryogenic heat exchanger (MSCHE) is used in the cycle to decrease the temperature difference of heat transfer process and increase the energy efficiency. The two-stage expansion which means there are two evaporation processes which works at about-100°C and-55°C respectively. This can make better use of the cold energy of LNG. The available process parameters were investigated and given by process simulation with HYSYS software. The results show that the cold energy and exergy efficiency is 19.67% and 27.15%, respectively. The ethane could also be used as working fluid in this cycle and similar output power could be achieved.