A mass transfer column includes a feed device that is used to de-entrain liquid
and more uniformly distribute vapor across a horizontal cross section of the column
after a vapor or mixed phase stream has been directed into the column through a
radially oriented feed nozzle. The feed device includes an annular passageway formed
in the spacing between the column shell and an inner wall spaced inwardly from
the shell. A deflector with oppositely directed deflecting surfaces is positioned
at an inlet from the feed nozzle to the annular passageway and splits the vapor
or mixed phase stream into two roughly equal streams that flow in opposite circumferential
directions in the annular passageway. At least one pair of turning vanes is spaced
on opposite sides of the deflecting surfaces in the annular passageway to create
subpassages through which the vapor or mixed phase stream flows. The subpassages
reduce the amount of vapor or mixed phase stream flow that impacts against the
inner wall of the feed device at the inlet. The turning vanes unexpectedly reduce
the pressure drop that occurs as the vapor or mixed phase stream is redirected
from its radial entry direction to the circumferential direction in the annular
passageway. By reducing the pressure drop, improvements in product yield and vapor
distribution can be achieved.
