Skid-Mounted SMR Packages for LNG Production: Configuration Selection and Sensitivity Analysis

On review of skid-mounted LNG technology providers, single mixed refrigerant (SMR), ni-trogen expander and self-refrigerated processes have been used for LNG production in skid scale. However, SMR processes are more efficient and have lower rotating equipment. By RIPI comparative study on commercialized SMR processes and more than 100 patents in this topic, the SMR process with one phase separator (by 43% sharing in SMR processes), has been selected for skid LNG plant. Regarding to process complexity of multi-phase separators in SMR loop, these types of cycles were not selected. Otherwise SMR process without phase separator was not selected for skid LNG plant because of the freezing possibility of heavy hydrocarbon refrigerants in this configuration. Several single-phase separator SMR processes can be used based on arrangement of equipment in liquefaction and refrigeration sections. By extensive study and according to skid design limitations (e.g., the minimum number of fixed and rotating equipment, minimum process complexity and dimension and etc.), two process arrangements has been selected, simulated and optimized. Also, a sensitivity analysis on the feed pressure and temperature as well as the composition of MR and feed was done. Energy consumption of these two configurations was calculated and the complexity of them was compared. According to the results obtained in this study and considering lower total annualized cost of LNG unit and the necessity of pro-cess simplicity in the skid scales, the best case was recommended for LNG skid-mounted packages.