Dynamic simulation of mixed refrigerant process for small-scale LNG plant in skid mount packages

The utilization of small natural gas reservoirs has attracted more and more attention. Most of the optimization studies concentrated on mixed refrigerant liquefaction process at steady-state simulation. Only a few studies have reported dynamic simulation of mixed refrigerant LNG (liquefied natural gas) process. The main purpose of this study was to design a dynamic model of mixed refrigerant LNG process for small-scale LNG plant in skid mount packages and to investigate the dynamic behaviors of this process. The variations of natural gas temperature, composition, pressure, flow rate and water-cooler temperature were selected as disturbances to test the stability and dynamic responses of the process. The dynamic responses of LNG temperature and total compressor energy consumption were the criteria to investigate the influences of disturbances on the process. Finally, the dynamic responses of disturbances were obtained and discussed. The simulation results showed that LNG temperature could go back to its set point value after a few minutes, while compressor duty varied with the disturbances. It indicated that the mixed refrigerant liquefaction process for small-scale LNG plant in skid mount packages could overcome some disturbances and operate at stable state.