REDUCING THE AMOUNT OF COMPONENTS HAVING LOW BOILING POINTS IN LIQUEFIED NATURAL GAS

摘要

Method of reducing the amount of components having low boiling points in liquefied natural gas (1) comprising passing the liquefied natural gas at liquefaction pressure through the hot side (2) of an external heat exchanger (3) to obtain cooled liquefied natural gas (6), allowing the cooled liquefied natural gas to expand dynamically (9) to an intermediate pressure and statically (10) to a low pressure to obtain expanded fluid (15), and introducing expanded fluid into the upper part of a fractionation column (20) provided with a contacting section (25) arranged between the upper part and the lower part of the fractionation column; passing a direct side stream (32) at low pressure through the cold side (30) of the external heat exchanger (3) to obtain heated two-phase fluid (36); introducing the heated two-phase fluid into the lower part (28) of the fractionation column (20) and allowing the vapour to flow upwards through the contacting section (25); allowing the liquid of the expanded fluid to flow downwards through the contacting section (25); and withdrawing from the lower part of the fractionation column (20) a liquid product stream (45) having a reduced content of components having low boiling points, and from the upper part of the fractionation column a gas stream (47) which is enriched in components having low boiling points.