Thermo-economic analysis of a natural gas liquefaction plant

Abstract Increasing worldwide energy demand requires the replacement of fossil fuel sources with clean and alternative ones to limit the chances of a climate collapse. In this scenario, natural gas supplies approximately 30% of total energy demand and is forecasted to become increasingly important in the near future. SOx emission limits for maritime transportation redefined by the International Maritime Organization (IMO) and the implementation of the European Directive for Alternative Fuels Infrastructure (DAFI) are going to produce a fast growth in LNG consumption in the coming decades. A thermo-economic analysis of a natural gas liquefaction plant has been conducted. The scheme is a simplified version of ConocoPhillips Optimized Cascade process that takes into account all principal components such as compressors, heat exchangers, after coolers and storage tanks. The aim of this paper is firstly a thermodynamic analysis of a three-pressure levels plant and, secondly, an economic evaluation of the solution, in order to compare the cost of LNG produced with its price on the market. In the end, sensibility analyses have been executed to consider market price variations and estimation errors concerning assumptions made.