A multi-channel modular device (10) processes between two fluid streams of different compositions. The device (10) includes a porous body (150) having a first plurality of feed-flow pathways (110) disposed in the body (150) for transporting a first stream (180). A pathway wall (114) surrounds each of the first plurality of feed-flow pathways (110) for processing the first stream (180) into a first composition (1852) and a second composition (1802). At least one feed-flow inlet (1101) is disposed in the body (150) for introducing the first stream (180) into the first plurality of feed-flow pathways (110). At least one feed-flow outlet (1102) is disposed in the body (150) for discharging the remaining first stream containing the second composition (1802). At least one second pathway (210) is disposed in the body (150) for transporting a second stream (280) having a second inlet (2101) and a second outlet (2102). A networked plurality of fluid conduits (152) formed in the porous body (150) provides the flow-conduit for the second stream (280) to sweep the first composition (1852) from each of the first plurality of the feed-flow pathways (110) to the second outlet (2102). A vessel (300) ports the inlets (1101 and 2101) and outlets (1102 and 2102) to provide a second stream flow access and for spacing the body within and away from the inner surfaces of the vessel (300) to provide a gap (310) for access. A partition (350) is disposed in the gap between the body and the vessel for diverting the flow within the gap (310).