Technical and Economic Comparison of the Effect of Absorption Pre-cooling on Natural Gas Liquefaction Plants for Supplying the Fuel of Shahid Rajaee Power Plant

Iran is using natural gas as the main energy carrier in many sectors. Establishing peak-shaving liquefaction units due to reduction in volume of natural gas, is the most desirable way to store surplus natural gas in the warm seasons and using it in cold seasons of the year. Due to the high cost of operating and maintenance of liquefaction cycles, inventing solutions aimed at reducing energy consumption and improving the economy of these units, is really important. In this research, along with selecting Shahid Rajaee power plant in Qazvin as case study, the natural gas liquefaction cycle with mixed refrigerant and absorption refrigeration pre-cooling with the purpose of supplying the fuel of total unit of this power plant for 60 days was established. Then, it was subjected to technical and economic analysis and in terms of operational parameters was compared with common single mixed refrigerant cycle (without precooling). Results show that in comparison to common single mixed refrigerant cycle the specific power consumption %43, the cost of liquefaction plant equipment %15, the flow rate of mixed refrigerant %69 decreased and the figure of merit %28.36 increased.