A mass exchange column (10,20,30,60,80,90) for exchanging mass between a first fluid stream (24,64) comprising a first fluid phase, and a second fluid stream (25,65) comprising a second fluid phase, wherein said first fluid phase is selected between a liquid phase and a gas phase, wherein said second fluid phase is a liquid phase, said mass transfer column comprising: - a vertical elongated container having a longitudinal dividing wall within said container, said container defining with said dividing wall at least a first exchange chamber and a second exchange chamber (76,77); - a feed means for feeding said first fluid stream into said first chamber; - a first extraction means for extracting said first fluid stream from said second chamber; - a source of said second stream; - a means for extracting said second stream; - a contact means (63,83) for causing a contact between said first stream (24,64) and said second stream, said contact means arranged within said first exchange chamber and/or within said second exchange chamber (76,77); - a longitudinal passageway (86,90) that extends between an outlet port from said first exchange chamber and an inlet port leading into said second exchange chamber (76,77), said passageway arranged in a proximity of said dividing wall, for conveying said first stream (24,64) from said first exchange chamber into said second exchange chamber (76,77); wherein said passageway comprises a portion of the dividing wall, and wherein said contact means and/or said passageway (86,90) are such that in said passageway (86,90) said first stream (24,64) comprises an amount of a substance in said second fluid phase, - a phase separation means comprising a settling chamber made within said passageway, said settling chamber arranged to form a main lighter fluid-phase portion of said first stream and a secondary heavier fluid-phase portion of said first stream, wherein said secondary heavier fluid-phase portion comprises at least one part of said amount of substance in said second fluid phase, characterised in that said settling chamber comprises - an inlet port that is in communication with passageway 86, so as to be arranged to receive said first stream; - a first flow port (43,43') to allow the outlet of said main lighter fluid-phase portion, comprising a gas or a liquid, said flow port (43,43') pneumatically or hydraulically connected with said feed/distribution means for feeding said main lighter fluid-phase portion of said first stream at a predetermined feed height of said second exchange chamber (76,77), said settling chamber having: - a second flow port (44,44') arranged to allow the outlet of said secondary heavier fluid-phase portion, which may be a liquid, or a heavier liquid, in order to remove said amount of a liquid or of a second liquid phase from said first stream upstream of, or at most, at said inlet port into said second exchange chamber (76,77). - a vertical elongated container having a longitudinal dividing wall within said container, said container defining with said dividing wall at least a first exchange chamber and a second exchange chamber (76,77); - a feed means for feeding said first fluid stream into said first chamber; - a first extraction means for extracting said first fluid stream from said second chamber; - a source of said second stream; - a means for extracting said second stream; - a contact means (63,83) for causing a contact between said first stream (24,64) and said second stream, said contact means arranged within said first exchange chamber and/or within said second exchange chamber (76,77); - a longitudinal passageway (86,90) that extends between an outlet port from said first exchange chamber and an inlet port leading into said second exchange chamber (76,77), said passageway arranged in a proximity of said dividing wall, for conveying said first stream (24,64) from said first exchange chamber into said second exchange chamber (76,77); - a phase separation means comprising a settling chamber made within said passageway, said settling chamber arranged to form a main lighter fluid-phase portion of said first stream and a secondary heavier fluid-phase portion of said first stream, wherein said secondary heavier fluid-phase portion comprises at least one part of said amount of substance in said second fluid phase, characterised in that said settling chamber comprises - an inlet port that is in communication with passageway 86, so as to be arranged to receive said first stream; - a first flow port (43,43') to allow the outlet of said main lighter fluid-phase portion, comprising a gas or a liquid, said flow port (43,43') pneumatically or hydraulically connected with said feed/distribution means for feeding said main lighter fluid-phase portion of said first stream at a predetermined feed height of said second exchange chamber (76,77), - a second flow port (44,44') arranged to allow the outlet of said secondary heavier fluid-phase portion, which may be a liquid, or a heavier liquid,