Gas-liquid contact apparatus

A tray assembly is provided for improved gas/liquid contact when used in a large chemical process tower, resulting in better performance. Each tray assembly has two levels of tray decks and associated downcomers. Tray decks provide gas/liquid contact for mass transfer and the downcomers are required to clarify the liquid before entering the tray below. A novel downcomer configuration is provided for use in multipass trays. The shape of downcomer bottom chord is designed to allow for liquid to travel across any part of each tray deck at a similar distance between the inlet and the outlet weir. As a result, liquid on the tray deck travels in plug flow pattern. Benefits include a higher Murphree tray efficiency due to minimum liquid back-mixing, as well as minimum local entrainment due to uniform froth height.