Energy recovery during liquefied natural gas regasification

Abstract

Paper presented at the 7th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Turkey, 19-21 July, 2010.In the liquefied natural gas (LNG) regasification process, the cold exergy can be recovered as electric power. For this purpose, in the present study, a simple open Brayton cycle was considered as a base cycle and its efficiency was improved by adding different equipment step by step. This procedure resulted in the investigation of four different cycles. The comparison of the results led to the proposal of a combined cycle that could recover the LNG cold energy most efficiently. This cycle consists of three parts; an LNG directly expanding cycle, a middle-pressure close Brayton cycle with nitrogen as working fluid, and finally an open gas turbine power cycle. All the cycles were analyzed based on the first and second laws of thermodynamics. Finally, the effects of different parameters upon the thermal and exergetic efficiencies were examined.