Patent ID: 7310972

Claim:
A process for separating a feed liquefied natural gas containing at least methane and a hydrocarbon less volatile than methane, into a product natural gas enriched with methane and lean in the hydrocarbon less volatile than methane and a heavier fraction lean in methane and enriched with the hydrocarbon less volatile than methane, using a distillation column, comprising the steps of: (a) heating the feed liquefied natural gas in a heat exchanger; (b) passing the fluid heated in step (a) into a distillation column; (c) withdrawing the heavier fraction from a bottom part of the distillation column; (d) withdrawing a residue gas from a top part of the distillation column; (e) liquefying a part of the residue gas in the heat exchanger; (f) refluxing a part of the liquid portion of the fluid obtained in step (e) into the distillation column; (g) withdrawing, as the product natural gas, the remainder of the liquid portion of the fluid obtained in step (e), which has not been fed into the distillation column in step (f); (h) heating the fluid heated in step (a), in a heat exchanger different from the heat exchanger used in step (a), prior to step (b); (i) separating a gas portion from the fluid obtained in step (e) and then pressurizing the gas portion; (j) liquefying the whole portion of the fluid obtained in step (i), in the heat exchanger used in step (h); and (k) withdrawing the fluid obtained in step (j) as a product natural gas.