Comparative evaluation of LNG – based cogeneration systems using advanced exergetic analysis

During the last two decades the total cost of LNG technology has decreased significantly due to improvements of the liquefaction process. However, the regasification system has not been considerably improved. It is known that for the regasification process about 1.5% of LNG is used. Two novel, gas-turbine-based concepts for combining LNG regasification with the generation of electricity are discussed in this paper. These concepts have relatively low investment costs and high efficiencies. An advanced exergetic analysis is applied to one of these attractive LNG-based cogeneration systems to identify the potential for improvement and the interactions among components. In an advanced exergetic analysis, the exergy destruction within each component is split into unavoidable/avoidable and endogenous/exogenous parts. The advantages of this analysis over a conventional one are demonstrated. Some new developments in the advanced exergetic analysis and options for improving the concepts are also presented.