A novel LNG reproduction layout using ejector refrigeration, an auto-cascade refrigeration system, and an ethylene compression refrigeration cycle

In this research, a novel liquefied natural gas (LNG) reproduction process is developed to re-liquefy generated boil-off gas from the LNG tank through an ejector refrigeration unit driven by an organic Rankine cycle, an auto-cascade refrigeration, and an ethylene compression refrigeration cycle. The developed system is evaluated through exergy efficiency, exergy destruction, coefficient of performance, and specific energy consumption indexes. Exergy destruction evaluation shows that heat exchangers and compressors are the most destructive equipment in the developed layout. The presented cycle obtains an exergy efficiency of 0.5936. It has been shown that increasing the adiabatic efficiency of the compressor leads to increasing the coefficient of performance while it decreases the required specific energy consumption. In addition, it has been monitored that increasing the boil-off gas re-liquefaction pressure yields an increase in the specific energy consumption. Besides, it has been illustrated that turbine inlet temperature is a crucial factor in the performance of the system, and achieving higher temperature has a positive factor on the whole system.