VOLATILE COMPONENT REMOVAL PROCESS FROM NATURAL GAS

摘要

A process is disclosed to remove at least one high volatility component, such as nitrogen, from a pressurized natural gas to produce pressurized liquefied natural gas that is lean in nitrogen and has a temperature above about -112 DEG C (-170 DEG F). A pressurized feed natural gas (10) containing nitrogen is expanded (33) and passed to a fractionation column (34). The fractionation column (34) produces a first vapor stream (19) that has enhanced nitrogen content and a first liquid stream (20). The vapor stream (19) is cooled to produce a vapor phase (23) and a liquid phase (22). The vapor and liquid phases are then phase separated to produce a second vapor stream and a second liquid stream. The second liquid stream is returned to the fractionation column as reflux (22). The second vapor stream is preferably used to cool the incoming feed stream. The first liquid stream is removed from the fractionation system as a product stream lean in nitrogen.