The natural gas liquefaction process is an energy intensive process due to its low temperature. Compressor units are one of primary factors in minimizing energy consumption of natural gas liquefaction process. Among various natural gas liquefaction processes, C3-MR (Propane Pre-cooled Mixed-Refrigerant) process is the most commonly used in LNG market. C3-MR process uses two types of refrigerants such as mixed-refrigerant and pure-refrigerant. In this study, pure-refrigerant cycle is simulated, along with different compressing ratios and different pressure levels. The simulation of case studies shows that energy consumptions mainly depend on both compressing ratios and pressure levels.. This study has achieved the energy consumption savings by 27.7% through different case studies with an emphasis on compressing ratios and pressure levels.