Application of exergetic analysis for LNG regasification process optimisation and redesign: case study of FSRU

Abstract

Today the world energy market is in great transition and the demand for clean energy such as liquefied natural gas (LNG), which is increasing rapidly. Offshore large-scale terminals as Floating Storage Regasification Unit (FSRU) type are becoming commercially competitive and effective alternative for the areas where onshore gas supply infrastructure is not feasible. LNG production consumes energy (around 850 MJ per ton) and it is stored in the form of “cold energy” which is dumped into seawater or the atmosphere during LNG regasification process despite reusing as extra energy source in many processes. In this research work, mathematical model is performed to determine influence of LNG composition and regasification process parameters to quantity of released LNG cold energy in a large scale FSRU type terminal. It was determined that the potential of LNG cold energy at FSRU could vary from 20 to 25 MWh depending on LNG regasification flow rate, pressure, BOG recondensation as well as composition of LNG.