Abstract: Mass transfer apparatus such as a distillation or rectification column which is divided so that the vapor flow is in two streams each in a separate zone, and wherein in each zone the liquid/vapor contacting stages have an inlet and an outlet disposed on opposite sides of an active area but to the same side of the division and such that liquid flow from the inlet across the active area to the outlet is generally rectiliner and parallel to the plane of the division, the locations of the stages in one zone being staggered axially relative to those of the stages in the other zone along the column and the liquid from each outlet being directed to an inlet of the next lower stage in the column whereby the liquid flow down the column is directed alternately from one zone to the other as it is passed successively from stage to stage down the column.

Abstract: Mass transfer apparatus such as a distillation or rectification column which is divided so that the vapor flow is in two streams each in a separate zone, and wherein in each zone the liquid/vapor contacting stages have an inlet and an outlet disposed on opposite sides of an active area but to the same side of the division and such that liquid flow from the inlet across the active area to the outlet is generally rectilinear and parallel to the plane of the division, the locations of the stages in one zone being staggered axially relative to those of the stages in the other zone along the column and the liquid from each outlet being directed to an inlet of the next lower stage in the column whereby the liquid flow down the column is directed alternately from one zone to the other as it is passed successively from stage to stage down the column.