Simulation and Thermodynamic Analysis of a Closed Cycle Nitrogen Expansion Process for Liquefaction of Natural Gas in Mini-scale

In this study a closed nitrogen expansion cycle (Niche) has been simulated with Aspen HYSYS V8.4. Energy and exergy analysis were applied to evaluate the process. Results of energy analysis indicated that specific power consumption of this process is 0.68 kWh/kg LNG. The results of exergy analysis showed that exergy efficiency of Niche LNG is 35.51%. It is concluded there is an interaction between specific power consumption and exergetic efficiency. Moreover, the highest value of exergetic efficiency and irrevsibility belong to compressor (C3) and gas turbine (E1). Moreover, this process can be suitable for mini-scale LNG plants.