Patent ID: 11885561
Assignee: CONOCOPHILLIPS COMPANY
Field: Chemical engineering (Chemistry)
Classification: CPC F  C | IPC C  F

Claim 8:
9. A method for liquefying natural gas in an offshore facility to produce liquified natural gas (LNG), said method comprising:
a) cooling a natural gas stream in an offshore LNG facility via indirect heat exchange in a first refrigeration cycle with a first azeotropic mixture of 85 mole percent propane and an 15 mole percent 1234yf, wherein the laminar burning velocity (LBV) of said first azeotropic mixture is about 40 cm/s and decreases the risk of vapor cloud explosion as compared to mixtures of greater than 40 cm/s; and then
b) further cooling the natural gas stream via indirect heat exchange in a second refrigeration cycle with a second azeotropic mixture of 1234yf and ethylene; and then
c) further cooling the natural gas stream in an open refrigeration cycle with 75-100 mole percent methane, wherein about 50 mole percent of said methane originates from LNG produced in step d in said method; and
d) producing LNG.