Patent ID: 7600395

Claim:
A method of liquefying natural gas, said method comprising the steps of: (a) cooling the natural gas via indirect heat exchange with a first refrigerant, thereby providing a cooled natural gas stream; (b) using a heavies removal column to separate the cooled natural gas stream into a lights stream and a heavies stream; (c) cooling at least a portion of the lights stream via indirect heat exchange with a second refrigerant of different composition than the first refrigerant, thereby providing a cooled lights stream; (d) separating the cooled lights stream into a predominately liquid phase lights stream and a predominately gas phase lights stream; (e) introducing at least a portion of the predominately liquid phase lights stream into the heavies removal column; and (f) introducing a portion of the natural gas stream into the heavies removal column as a stripping gas, said heavies removal column including a first inlet for receiving the cooled natural gas stream, a second inlet for receiving the predominately liquid phase lights stream, a third inlet for receiving the stripping gas, a first outlet for discharging the lights stream, and a second outlet for discharging the a heavies stream, said first outlet and said second inlet being vertically disposed above the first inlet, said second outlet being vertically disposed below the first inlet, said third inlet being vertically disposed below the first inlet.