Removing carbon dioxide,ethane and heavier components from a natural gas

摘要

Removing carbon dioxide, ethane and heavier components from high pressure natural gas (10) comprises: partly condensing and expanding the high pressure natural gas (10) to obtain a gaseous stream (30) enriched in methane and carbon dioxide and two liquid.streams (37 and 40) enriched in ethane and heavier components which are introduced into fractionation column (35); removing from fractionation column (35) fluid stream (45), heating (46) the fluid stream to obtain a reboiling stream (47) which is introduced into the fractionation column (35); removing from fractionation column (35) liquid stream (50) enriched in carbon dioxide, ethane and heavier components; removing from the top of fractionation column (35) a gaseous overhead stream (55) enriched in methane; cooling (56) the gaseous overhead stream (55) to obtain a two-phase fluid, separating (58) the two-phase fluid into cooled gaseous overhead stream (60) and first reflux stream (62) which is introduced into the fractionation column (35); and expanding (65) the cooled gaseous overhead stream (60) to obtain a two-phase fluid at low pressure separating (69) the two-phase fluid into gaseous product stream (70) and second reflux stream (72) which is introduced into the top of the fractionation column (35).