Performance enhancement of propane pre-cooled mixed refrigerant LNG plant

Liquefied Natural Gas (LNG) and chemical processing are energy-intensive facilities, such that any enhancement of their efficiency will result in abundant reduction of energy consumption and green house gas emissions. To enhance LNG plant energy efficiency, the potential of various options for improving liquefaction cycle efficiency is investigated in this study. After developing models for the LNG process using ASPEN software, four expansion loss recovery options are simulated. The simulation results show that the compressor power reduction, expansion work recovery, and LNG production increase can be achieved as much as 2.68 MW, 3.82 MW, and 1.24%, respectively, by replacing conventional expansion processes with expanders. By implementing all of the enhancements, the power consumption per unit mass of LNG could be reduced by 7.07% and 3.68%, with and without considering deduction of the recovered power from the total required power, respectively. Therefore, the expansion work recovery is an important option to be implemented in LNG plants.