Patent ID: 7231784

Claim:
A method for producing liquefied natural gas comprising: (A) removing water from a first natural gas stream in a first adsorption unit to produce dehydrated natural gas, cooling the dehydrated natural gas to a temperature below the critical temperature of methane to produce cooled dehydrated natural gas, expanding the cooled dehydrated natural gas in a subambient expansion to produce depressurized natural gas, warming the depressurized natural gas, and using a portion of the warmed depressurized natural gas as regeneration gas in the first adsorption unit; and (B) removing carbon dioxide and water from a second natural gas stream in a second adsorption unit to produce clean natural gas, liquefying a portion of the clean natural gas to produce liquefied natural gas, and using another portion of the clean natural gas as regeneration gas in the second adsorption unit wherein the depressurized natural gas for use as regeneration gas for the first adsorption unit is generated by a subambient Joule-Thomson valve expansion, a subsequent compression, and then a subambient turboexpansion.