Mixed refrigerant cycles can improve refrigeration efficiency

and are used widely in natural gas liquefaction systems. The effect of mixed refrigerant cycle (MRC) stages on refrigeration performance is significant. Thermodynamics models of the main pieces of equipments in the MRC were built. Natural gas liquefaction processes with MRC were simulated. Most of the process parameters

including shaft power of compressors

refrigeration efficiency and exergy efficiency of different numbers of stages of MRC were obtained. With increasing number of stages of MRC

the shaft power of compressors decreased

while the refrigerant efficiency and exergy efficiency increased. But the rate of decrease and increase declined. Multi-stage cycles made the process configuration complex and operation difficult. Different sizes of refrigeration systems had different optimum number of stages. The larger the size of refrigeration system

the greater the number of stages. A balance must be made between energy efficiency and complexity.