Abstract: A mass transfer column (20) is provided with an external shell defining an open internal region. Centrifugal contact trays (26) and return contact trays (28) are positioned in an alternating and vertically spaced apart relationship within the open internal region. Each contact tray has a plurality of vapor passages (33) for allowing vapor to flow upwardly through the tray deck to interact with liquid on the surface of the tray deck. At least one center downcomer (40) extends downwardly at an opening in the return tray deck and has a lower discharge outlet spaced above the centrifugal tray deck for feeding liquid onto the centrifugal tray deck. A rotation-inducing element may be placed within the center downcomer (40) to induce a rotational motion in liquid exiting the center downcomer (40). At least one annular downcomer (36) extends downwardly the periphery of the centrifugal tray deck and has a lower discharge outlet spaced about the return tray deck for feeding liquid onto the return tray deck.

Abstract: A vapor-liquid contact tray (26) is provided with a tray deck (28) having at least one opening for removing liquid from an upper surface of the tray deck and a plurality of vapor passages (44) for allowing vapor to flow upwardly through the tray deck to interact with the liquid on the upper surface. At least one can (34) extends upwardly from the tray deck and is formed by a perimeter wall (36). A downcomer (46) is interposed within the can to provide a passageway for liquid and has an upper inlet (50)for liquid entry, and a lower outlet (54) above the tray deck (28) for feeding liquid into the can and onto the tray deck. A plurality of deflector blades (56) are positioned above the tray deck to induce a swirling movement in the vapor ascending into the can. The portion of the tray deck surrounded by the perimeter wall of the can contains sieve holes, valves or other types of vapor passages. The tray may further include a sleeve (76), a plurality of cans (34) of two or more sizes or combinations thereof.

Abstract: A mass transfer column (20) is provided with an external shell defining an open internal region. Centrifugal contact trays (26) and return contact trays (28) are positioned in an alternating and vertically spaced apart relationship within the open internal region. Each contact tray has a plurality of vapor passages (33) for allowing vapor to flow upwardly through the tray deck to interact with liquid on the surface of the tray deck. At least one center downcomer (40) extends downwardly at an opening in the return tray deck and has a lower discharge outlet spaced above the centrifugal tray deck for feeding liquid onto the centrifugal tray deck. A rotation-inducing element may be placed within the center downcomer (40) to induce a rotational motion in liquid exiting the center downcomer (40). At least one annular downcomer (36) extends downwardly the periphery of the centrifugal tray deck and has a lower discharge outlet spaced about the return tray deck for feeding liquid onto the return tray deck.

Abstract: The flooding capacity of a fractionation tray (2) is increased by the addition of at least one layer of low surface area grids (3) above the inlet to the downcomers (6,12) located on the tray (2). The grids (3) extend upward for a distance equal to one to four times the depth of the downcomers. The grids may rest upon the top edge of the downcomers or on the tray decking between the top portions of the downcomer sidewalls.

Abstract: A novel fractionation column (1) internal structure consists of groups of fractionation trays in which the upper trays rest upon the bottommost tray of the group, which is the only tray of the group supported by the column wall. Preferably the downcomers (13) or disengagement plates of the upper tray rest upon the tops of the downcomers (13) of the next lower tray. Only the bottom tray is supported as by a ring (12) attached to the column.

Abstract: A novel fractionation tray (1) includes slidable decking plates (4) located between and alongside parallel downcomers (2). The decking plates located between a pair of downcomers have sections which may be extended outward toward the edge of the tray to adapt the shape of the tray to the internal shape of the column in which it is installed. A method of installing the trays, with an upper tray being supported only by a lower tray, is also disclosed.

Abstract: A novel fractionation column (1) internal structure consists of bundles of fractionation trays in which each upper tray rests upon the next lower tray. Only the lowermost tray of the bundle is supported by the column wall. Preferably the downcomers (13) of the upper tray rest upon the tops of the downcomers (13) of the next lower tray. The two crescent-shaped terminal decking sections (19) on opposite edges of the tray are supported from below by arch-shaped structures (17) anchored to the next lower tray.

Abstract: High vapor and liquid capacity counterflow fractionation trays demonstrating superior turndown and performance characteristics include a number of parallel downcomers separated by planar tray decking having unique bidirectional slotted cap valve geometries. Several different arrangements of the bidirectional valves are presented. The raised trapezoids of the bidirectional valves may be arranged in two groups which each face the nearest downcomer, or arranged in lines parallel to the downcomer sidewalls such that trapezoids of neighboring rows face opposite directions. In a third embodiment these bidirectional slotted cap valves are only located in the regions of the decking sections located next to the downcomers.

Abstract: High capacity, low cost fractionation trays are formed from a number of adjacent triangular (v-shaped) downcomer modules. The trays are free of the horizontal perforated decking surface of conventional trays. The downcomer modules have perforations only in a bottom region for liquid passage and in an upper region for vapor passage, with the central portion of the two inclined downcomer sidewalls being imperforate. The difference in elevation between the bottom region and upper region is considerably larger than a ripple tray. A layer of packing material may be provided close to or adjacent the bottom surface of the tray.

Abstract: Fractionation trays are provided with an antipenetration pan which intercepts liquid falling from the downcomer of a vertically superior tray. The antipenetration pans are supported above the surface of the lower tray by brackets attached to the tray decking and to a horizontal deck brace which extends across the tray deck at the location of a joint or splice between adjacent tray deck plates. The invention thereby provides a simple, low cost and easy to install integral antipenetration pan and tray splice construction.

Abstract: High capacity, low cost fractionation trays are formed from a number of adjacent triangular (v-shaped) downcomer modules. The trays are free of the horizontal perforated decking surface of conventional trays. The downcomer modules have perforations only in a bottom region for liquid passage and in an upper region for vapor passage, with the central portion of the two inclined downcomer sidewalls being imperforate. The difference in elevation between the bottom region and upper region is considerably larger than a ripple tray. A layer of packing material may be provided close to or adjacent the bottom surface of the tray.

Abstract: High capacity, low cost fractionation trays comprise a flat perforated decking surface sectioned into parallel contacting areas by triangular downcomers. The bottom edges of two inclined sidewalls join together to form V-shaped downcomers having a limited number of perforations in their sidewalls to allow downward liquid passage. An imperforate zone is present in the central region of each sidewall. A layer of packing material may be provided close to or adjacent the bottom surface of the tray. The packing is located in the disengagement zone under the tray but does not extend downward to the next tray below.

Abstract: The vapor capacity of multiple downcomer type fractionation trays is increased by the provision of vapor directing slots in the tray deck, with the slots being oriented toward the closest downcomer to reduce froth height. The slots located in the relatively narrow deck area between downcomers are accordingly divided into two sets which point in opposite directions. Vertical baffles are provided above the downcomer inlets. The baffles preferably extend upward to slightly below the lower surface of the next higher tray, with the upper edge of the baffles being notched to accommodate the downcomers of this next higher tray.

Abstract: The capacity of multiple downcomer type fractionation trays is increased by providing imperforate calming decks (6) which extend across the tray deck (2) surface outward from the conventional downcomer inlet opening together with vertical inlet weirs (8) attached to the outer end of the calming decks (6). The inlet weirs (8) may function as "preweirs" used in addition to the conventional inlet weir formed by the upward extension of the downcomer sidewall (4).

Abstract: The efficiency of multiple downcomer type fractionation trays is increased by increasing the length of the liquid flow path and providing Lewis Case II point to plate efficiency enhancement. Baffles (7) extending axially along the vertical axis of a fractionation column divide the intertray volumes of the column into defined vapor passageways. A pair of inclined liquid deflecting baffles (3) over each downcomer (10) connects the outlets and inlets of vertically adjacent downcomers and provides a crisscrossing liquid flow path. Beds (14) of vapor-liquid contacting material increase tray efficiency.

Abstract: The efficiency of multiple downcomer type fractionation trays is increased by increasing the length of the liquid flow path and providing Lewis Case II point to plate efficiency enhancement Baffles (7) extending axially along the vertical axis of a fractionation column divide the intertray volumes of the column into defined vapor passageways. A pair of inclined liquid deflecting baffles (3) over each downcomer (10) connects the outlets and inlets of vertically adjacent downcomers and provides a crisscrossing liquid flow path.

Abstract: The efficiency of multiple downcomer type fractionation trays is improved by the provision of an individual antipenetration pan located under each set of openings in the bottom of the box-like downcomers. The pans preferably comprise perforated planar sheets and have raised lips along two opposing edges to retard significant liquid runoff along the edges parallel to the downcomer end walls. The pans are parallel to the main tray surface and located intermediate the downcomers and the upper surface of the next lower tray.

Abstract: The performance of multiple downcomer type fractionation trays is stabilized against the effects of any rocking motion to which the surrounding column is subjected by the provision of vapor and liquid flow control baffles on the tray deck. One such baffle is perpendicular to the downcomers and extends upward. Vertical baffles are provided within and over the downcomers. A large number of bubble-promoting devices line the periphery of the tray.