Patent ID: 8132411

Claim:
A method for generating power in a vaporization of liquid natural gas process, the method comprising the steps of: (a) pressurizing a working fluid; (b) heating and vaporizing the pressurized working fluid; (c) expanding the heated and vaporized working fluid in two or more expanders in series for the generation of power, the working fluid exiting the two or more expanders in series comprises: 2-11 mol % nitrogen, methane, a third component whose boiling point is greater than or equal to that of propane, wherein the third component comprises at least 11 mol % of the working fluid; and a fourth component comprising ethane or ethylene; (d) cooling the expanded working fluid such that the cooled working fluid is at least substantially condensed; and (e) recycling the cooled working fluid into step (a), wherein the cooling of the expanded working fluid occurs through indirect heat exchange with a pressurized liquefied natural gas stream in a heat exchanger, and wherein the flow rate of the expanded working fluid at an inlet of the heat exchanger is equal to the flow rate of the expanded working fluid at an outlet of the heat exchanger.