Method and apparatus for preparing a lean methane-containing gas stream

摘要

A hydrocarbon feed stream is passed to an extraction column. A first portion of a liquid bottom stream from the extraction column is partly depressurized and subsequently passed, at reduced pressure, into a first fractionation column of a fractionation system. A recycle portion derived from a first residue liquid bottom stream removed as liquid from the first fractionation column is recycled into the extraction column, whereby the recycle portion enters the extraction column in liquid phase. The recycle portion has the same composition as the first residue liquid bottom stream being withdrawn from the first fractionation column. A vaporous overhead stream is withdrawn from the extraction column, from which a lean methane-containing gas stream is produced.