Aprovechamiento de la energía fría del gas natural licuado en buques regasificadores

Abstract

The present doctoral thesis studies the use of liquefied natural gas (LNG) cold energy to reduce greenhouse gas (GHG) emissions during the regasification process of floating storage regasification units (FSRUs). First, the regasification technology and scientific literature on power cycles for exploiting cold energy from LNG in regasification vessels is reviewed. Then, methods for energy, exergy and economic analysis of the systems are developed and implemented, as well as energy efficiency and environmental indexes and indicators applicable to FSRUs. Finally, two regasification systems are proposed to meet the electrical power demand on board and reduce GHG emissions to almost zero. The first system combines an organic Rankine cycle (ORC) with a CO2 capture system using chemical absorption that treats the flue gas from the steam generation process in the boiler. The second system uses seawater as a heat source and combines ORC stages in series with an open LNG cycle. The proposed systems are compared with the regasification systems installed on board the FSRUs.