Patent ID: 6994331

Claim:
A mass transfer column comprising: an external shell defining an open internal region; at least one return contact tray and at least one overlying centrifugal contact tray positioned in an alternating and vertically spaced apart relationship within the open internal region, said return contact tray comprising a tray deck having at least one opening for removing liquid from an upper surface of said return tray deck and a plurality of vapor passages for allowing vapor to flow upwardly through said return tray deck to interact with liquid on said upper surface of said return tray deck, said centrifugal contact tray comprising a tray deck having an upper surface, a periphery and a plurality of vapor passages for allowing vapor to flow upwardly through said centrifugal tray deck to interact with liquid on said upper surface of said centrifugal tray deck; at least one center downcomer extending downwardly at said opening in said return tray deck, said center downcomer having a lower discharge outlet; at least one annular downcomer extending downwardly at said periphery of said centrifugal contact tray deck and having a lower discharge outlet spaced above said return tray deck for feeding said liquid onto said return tray deck; and a plurality of baffles extending upwardly from said return contact tray at said center downcomer and supporting said overlying centrifugal contact tray.