Abstract: Methods and systems for removing nitrogen during liquefaction of natural are provided. Methods of removing nitrogen include warming a predominantly methane stream in a methane cold box to provide a warmed predominantly methane stream; conducting at least a portion of the warmed predominantly methane stream from the methane cold box to a nitrogen removal unit comprising at least a first nitrogen removal column and a last nitrogen removal column, wherein the first nitrogen removal column is located upstream of the last nitrogen removal column; passing the warmed predominantly methane stream through the last nitrogen removal column to provide a refluxed warmed predominantly methane stream; and routing at least a portion of the refluxed warmed predominantly methane stream to the last nitrogen removal column.

Abstract: Systems and methods for removing heavy hydrocarbons are provided. Methods for liquefying a natural gas stream include: (a) cooling at least a portion of the natural gas stream in an upstream refrigeration cycle of a liquefaction process to produce a cooled natural gas stream; (b) separating via a first distillation column the cooled natural gas stream into a first top fraction and a first bottom fraction, wherein the first fraction does not freeze in a subsequent downstream step of the liquefaction process; (c) separating via a second distillation column the first bottom fraction into a second top fraction and a second bottom fraction, wherein the second top fraction at least a portion of a reflux stream; (d) optionally separating via a third distillation column the second bottom fraction into a third top fraction and a third bottom fraction, wherein the third top fraction forms a portion of the reflux stream; and (e) introducing the reflux stream into the first distillation column.

Abstract: Methods and systems for removing nitrogen during liquefaction of natural are provided. Methods of removing nitrogen include warming a predominantly methane stream in a methane cold box to provide a warmed predominantly methane stream; conducting at least a portion of the warmed predominantly methane stream from the methane cold box to a nitrogen removal unit comprising at least a first nitrogen removal column and a last nitrogen removal column, wherein the first nitrogen removal column is located upstream of the last nitrogen removal column; passing the warmed predominantly methane stream through the last nitrogen removal column to provide a refluxed warmed predominantly methane stream; and routing at least a portion of the refluxed warmed predominantly methane stream to the last nitrogen removal column.