Abstract: The present invention discloses a method for recovering effective energy as power between liquefied natural gas and a high temperature source by cascading two kinds of Rankine cycles when the liquefied natural gas is re-gasified.

Abstract: A method is disclosed for processing LNG using a mixed heat medium for performing a Rankine cycle to gasify the LNG. The medium is prepared by batch distillation using only LNG. The method comprises the steps of condensing an upflow vapor in a single distillation column employing part of the LNG in an LNG batch distillation cycle, venting one fraction having low boiling point components mainly containing methane, and accumulating the other fractions containing ethane and components heavier than ethane. The supply of LNG to be distilled in the column is halted. A total condensing operation is performed in which the other fractions are sequentially condensed by part of the LNG at the condenser to sequentially recover and mix each component with the other fractions. LNG is added as the methane component to the recovered mixture of components to prepare a mixed heat medium consisting of components selected from hydrocarbons having 1-6 carbon atoms, or hydrocarbons having 1-6 carbon atoms and nitrogen.