Cost and economic potential analysis of a cascading power cycle with liquefied natural gas regasification

Abstract

Cost analyses and advanced exergoeconomic analyses are applied to a cascading power cycle with liquefied natural gas regasification. These analyses provide information about the causes of irreversibilities and determine the amount of avoidable irreversibility of the process. The results show that in all components except one of the gas turbines, most of the irreversibility is due to the endogenous exergy destruction. It also indicates that most of the exergy destruction except in combustion chamber is unavoidable, but that there is still a large potential to improve the performance of the system. In terms of avoidable endogenous exergy destruction cost rate, the analysis indicates that combustion chamber and one of the gas turbines should be modified first, because their avoidable endogenous exergy destruction cost rates are higher than those of other components. The cost of exergy destruction and investment in most of the process components are endogenous. So interactions among the components in these processes are not strong. The investment costs of the heat exchangers, one of the compressors, gas turbines and pumps are unavoidable due to technological and economic limits while other process equipment have potentials for improvement. Also based on the avoidable endogenous/exogenous part, three strategies are suggested to improve the performance of the components by reducing exergy destruction costs in the process components. The exergy efficiency and total exergy destruction rate of the process are about 59.4% and 159,600 kW, respectively.