MXPA00001844A - Downcomers for vapor-liquid contact trays - Google Patents

Abstract

A vapor-liquid contact tray (36) is provided with a tray deck (40) and an upstream downcomer (48) and a downstream downcomer (50) positioned at an opening (46) in the tray deck (40). The upstream downcomer (48) extends downwardly and is inclined in the direction of the upstream downcomer (48).

Description

DESCENDING DUCTS FOR STEAM-LIQUID CONTACT PLATES BACKGROUND OF THE INVENTION This invention is generally concerned with the transfer and mass exchange columns and more particularly with the down conduits used in association with the vapor-liquid contact plates used in such cases. columns The steam-liquid contact plates are used in the mass transfer or heat exchange columns to facilitate the interaction and transfer of mass between the descending liquid streams and the ascending vapor currents. The plates are generally arranged horizontally and spaced vertically within an open interior region of the column. Each dish commonly includes a flat cover portion that includes a plurality of vapor flow openings that allow the rising steam to pass through the dish cover and interact with the liquid flowing through the upper surface of the cover from the dish. A downward duct is positioned in an opening at an outlet end of the dish cover to remove the liquid from the cover and direct it downward to a liquid receiving area at the entry end of an underlying dish. Then the liquid flows through the cover of the underlying plate REF: 32635, interacts with the steam that passes through the plate cover and then flows down through the outlet down conduit associated with the next underlying plate. Then this flow configuration is repeated for each plate successively below. In conventional columns where high liquid flow rates are found, it has been suggested in US Pat. No. 5,213,719 that a second downward conduit can be used in each dish to increase the liquid handling capacity of the dish and thereby reduces the opportunity for flooding of the descending conduit. The second down conduit, referred to as the downstream duct upstream, is positioned adjacent to the downstream duct, and is shorter than the downstream duct in vertical length. Figure 1, taken from U.S. Patent No. 5,213,719, illustrates this construction of the downcomer with the downstream duct 10 upstream and the downstream duct 12 downstream positioned at the outlet end of the dish cover 14. It has also been suggested in U.S. Patent No. 5,453,222 that the inlet wall of the normally planar descending conduit can be formed in a semi-conical configuration to form a vapor tunnel along the lower surface of the semi-conical wall. The steam tunnel imparts a horizontal flow vector to the steam stream and facilitates the separation of the liquid from the steam stream. Figures 2 and 3 are taken from U.S. Patent No. 5,453,222 and illustrate a plate 16 with a down conduit 18 having a semi-conical inlet wall 20. Ventilation chambers 22 positioned in the channel or conduit 24 receiving the liquid in the underlying dish 26 allow steam to flow through the chambers 22 for passage upwards through the superimposed steam tunnel 28 formed by the inlet wall 20 of the semi-conical descending conduit. It would be desirable to combine the advantages provided by the double down conduit described in the aforementioned U.S. Patent No. 5,213,719 to those provided by a downcomer with a semi-conical inlet wall as taught by U.S. Patent No. 5,453,222 discussed above. However, several problems result from such combination because the downstream duct upstream needs to be of a relatively short vertical dimension, so that it does not protrude down to the steam tunnel and interfere with the desired flow of steam through the tunnel. steam. If a relatively short upstream duct is used, the liquid leaving the bottom of the downstream duct would be discharged directly into the steam stream that flows along the steam tunnel. The moment (or amount of movement) of the vapor stream will cause the discharged liquid to be expelled by blowing the descending conduit and through the plate. The vapor-liquid contact and exchange of energy and mass that occurs in such a blown liquid as it moves through the vapor is not as good as desired. In addition, the blown liquid would deviate from the portions of the dish cover and would not experience the vapor-liquid interaction that would otherwise occur if the liquid flowed completely through the dish cover. Therefore, it is desirable to minimize or eliminate this effect. Another undesirable effect that can occur as a consequence of using an upstream down conduit is that it can "exhaust" the flow of downstream or primary downstream conduit fluid under low flow conditions. A further consequence of this effect is that the downstream duct may have too little liquid flowing therethrough and may lose the seal of the liquid in the region of the bottom of the down duct which blocks the undesirable entry of steam into the down duct. The loss of the liquid seal will allow the vapor to flow up through the down conduit and deviate from the interaction with the liquid in the top plate. The possibility that such an effect will be presented decreases the flexibility of operation of the column taken as a whole. A further undesirable result of the use of an upstream duct of small vertical extension is that the liquid exiting the bottom of the downstream duct falls vertically downwardly downward to the dish cover. The large momentum (or momentum) of the falling liquid is transmuted into pressure when the liquid hits the plate below and locally decreases the vapor flow-in the impact area and consequently allows the liquid to be swept away. through the steam openings at that point on the plate cover. While the above undesirable effects of using an upstream short vertical extension downcomer have been described in connection with a downcomer system using a steam tunnel structure, those skilled in the art will appreciate that these undesirable effects can They can also be found when the downstream duct upstream is of slight vertical extension, even if there is no steam tunnel. Thus, it would be desirable to overcome these disadvantages in a double-duct system.

BRIEF DESCRIPTION OF THE INVENTION It is an object of this invention to provide a vapor-liquid contact plate with a double down conduit constructed in a manner that does not completely block the desired steam flow configuration in the area of the downcomer, but is apt to at least partially shield the liquid discharged from the upstream portion of the downcomer, such that the vapor flow does not transport the discharged liquid far away from the downcomer and thereby interferes with the desired vapor-liquid interaction in the vicinity of the descending conduit. It is also an object of this invention to provide a double down conduit which does not completely block the desired steam flow configuration and in which the upstream portion of the down conduit has a sufficient flow resistance, such that the liquid can accumulate within the upstream portion and overflowing to the downstream portion of the downcomer, thereby creating the liquid seal necessary to resist the flow of steam upwardly through the downstream portion of the downcomer. It is a further object of this invention to provide a double descending duct as described, which does not completely block the desired steam flow configuration, but is apt to discharge the liquid near the surface of the underlying dish cover in a manner that alters the downward moment (or amount of movement) of the liquid to reduce the incidence of liquid being swept through the vapor flow openings on the dish cover as a result of such moment (or amount of movement) downward. To accomplish these and other related objects of the invention, there is provided a vapor-liquid contact plate, comprising a plate cover having an opening for separating the liquid from an upper surface of the plate cover and a plurality of openings to allow steam to flow up through the dish cover to interact with the liquid on the upper surface. An upstream duct is provided and extends downwardly in the opening in the dish cover and has an inlet at an upper end to receive at least a portion of the liquid entering the opening from the dish cover and an outlet of bottom discharge through which at least part of the liquid portion leaves the downstream conduit. A downstream duct is also provided and extends downwardly in the opening of the dish cover and has a lower discharge outlet through which a second portion of the liquid leaves the downstream duct. A divider wall separates the downcomer downstream from the upstream downcomer along at least a portion of its lengths and an inlet wall defining a portion of the upstream downcomer is sloped downward toward the divider wall. In another aspect, the invention is concerned with a method for using the plates of. vapor-liquid contact to facilitate vapor-liquid interaction. The upstream, inclined downward duct discharges the liquid in the direction of the downstream downstream duct to reduce the vertical force with which the liquid impacts with the dish cover to facilitate mixing of the liquid with the discharge of the downstream duct below and prevent the entry of steam to the discharge outlet of the downstream down conduit.

BRIEF DESCRIPTION OF THE VARIOUS VIEWS OF THE DRAWINGS In the accompanying drawings that form part of the specification and will be read in conjunction therewith and in which like reference numbers are used to indicate like parts in the various views: Figure 1 is a fragmentary perspective view of a column of mass transfer of the prior art employing steam-liquid contact plates having double down conduits of the type illustrated in U.S. Patent No. 5,213,719; Figure 2 is a fragmentary perspective view of a mass transfer column of the prior art employing a vapor-liquid contact plate having a descending conduit with a frusto-conical or semi-conical wall forming a steam tunnel to facilitate the vapor flow upwards, also "as illustrated in U.S. Patent No. 5,453,222; Figure 3 is an enlarged, fragmentary, side elevational view taken in vertical section of the prior art contact plate shown in Figure 2; illustrating the vapor and liquid flow configurations; Figure 4 is a fragmentary view of a column containing single-dish plates constructed in accordance with the present invention and having inclined planar inlet walls; Figure 5 is a fragmentary side elevation view showing one of the plates of Figure 4, taken in vertical section along line 5-5 of Figure 4; Fig. 6 is a fragmentary side elevation view similar to that shown in Fig. 5, but showing an alternative embodiment of the one-way plate; Fig. 7 is a fragmentary side elevational view showing another embodiment of a single-step plate having semi-conical downcomer inlet walls; Fig. 8 is a fragmentary top plan view showing a further embodiment of a one-way plate having sloping downstream duct inlet walls which are multi-segmented cordales in construction; and Figure 9 is a fragmentary side elevational view similar to that shown in Figure 5, but illustrating a central descending portion of a two-step tray.

DETAILED DESCRIPTION OF THE INVENTION Turning now to the drawings in greater detail and initially to Figures 4-5, a heat exchange or mass transfer column is designated generally by the number 30 and includes a shell or vertical cylindrical cover 32 which defines an open interior region 34 in which a plurality of vapor-liquid contact plates 36 are contained. Column 30 is of a type used to process liquid streams and optionally steam streams, commonly to obtain fractionation products. Although the column 30 is shown in a cylindrical configuration, other shapes may be used, in which polygonal shapes are included. Column 30 can be of any suitable diameter and height selected for particular applications and can be constructed from any suitable rigid material. One or more streams of liquid can be directed to the column 30 via side stream feed lines and a high reflux return line that are not shown in the drawings due to their conventional nature. Also, one or more vapor streams may be charged to the column through side stream feed lines (not shown) or may be generated within the column 30. Other conventional aspects of the mass transfer columns, such as packing beds, liquid distributors and collectors, reboilers, condensers and the like are not illustrated but can be included in column 30 to carry out the desired processing of the liquid and vapor streams as they flow in countercurrent relation to through the column. The vapor-liquid contact plates 36 are placed in spaced apart relation vertically within the inner region 34 of the column 30 and are supported in a generally horizontal orientation by support rings 38 and optionally clamps 39 mounted on the inner surface from the column 30. Each plate 36 includes a plate cover 40 having an inlet end 42 wherein the liquid is introduced onto the plate cover 40 and an outlet end 44 where the liquid is removed from the plate cover through an opening 46 in the cover. The openings 47 are evenly distributed through the portion of the plate cover known as the "active area". The openings 47 allow steam to pass through the cover plate and interact with the liquid flowing through the upper surface of the cover. The openings 47 may comprise holes, valve structures or other conventional fractionation plate openings and have a size, shape and distribution for the particular operating conditions in which the plate 36 will be used. The openings 47 are commonly omitted from the liquid receiving portion of the inlet end 42 of the plate cover 40 but may be present if desired. At least one and preferably a plurality of the plates 36 include a downstream duct 48 upstream positioned in the opening 46 at the outlet end 44 of the cover 40 of the tray and a downstream duct 50 positioned adjacent to and downstream of the tray. downstream conduit upstream in the opening 46 of the plate cover. The down conduits 48 and 50 extend downwardly below the plate cover by a preselected distance to the underlying plate. A partition wall or divider wall 52 separates downstream ducts upstream and downstream 48 and 50 along at least a portion of their lengths and forms at least a portion of an inlet wall 53a for the downstream duct down and at least a portion of a wall 53b downstream for the downstream duct. The dividing wall 52 may be a single wall that serves as a common wall for both down conduits or may be a spaced apart double wall that allows the down conduits to be spaced apart if desired. The upstream downstream duct 48 is also formed in part by an inlet wall 54 which is preferably sloped downwards in the direction of the divider wall 52 and an inlet wall 53a for the downstream downstream duct 50. The remaining walls of the descending ducts are formed by the shell or cover 32 of the column, but separate walls can be used if desired. The downstream upstream and downstream passages 48 and 50 cooperate to withdraw the liquid from the outlet end 44 of the cover 40 of the dish and direct it downward to the inlet end 42 of the cover of the underlying dish. Both down conduits 48 and 50 have an upper inlet 56 and 58 respectively, through which the liquid enters the open upper part of the downcomer for downward passage therethrough and a lower unloading outlet 60 and 62 respectively through which the liquid is discharged onto the receiving portion of the liquid from the inlet end 42 of the cover 40 of the underlying plate. The discharge outlets 60 and 62 are preferably positioned at the level or at a slightly lower level of liquid level on the cover 40 of the underlying dish. The vertical spacing between the outlets 60 and 62 and the cover of the underlying plate may be the same as shown in Figures 5 and 7. Alternatively, the discharge outlet 62 of the downstream downpipe may be spaced above the outlet 60 discharge of the downstream conduit upstream and above the liquid level on the underlying plate as shown in Figure 6 or the upstream discharge outlet 60 could be positioned above the discharge outlet 62 of the downstream conduit . According to the present invention, the inlet wall 54 of the upstream downward duct 48 is inclined downward in the direction of the inlet wall 53a of the downstream duct. The inlet wall 53a is optionally inclined but preferably in the same direction as the inlet wall 54 of the downstream duct. The inclination of the inlet walls 53a and 54 in this manner reduces the total horizontal cross-sectional area of the discharge conduits 60 and 62 of the descending conduit relative to the upper inlets 56 and 58, thereby reducing the size of the area receiving the liquid on the inlet end 42 of the cover 40 of the underlying plate and allowing a greater active area and more area for the flow of steam over the plate cover. The decreased cross-sectional area of the outlets 60 and 62 also allows the upstream downstream duct to extend down to just above the cover 40 of the underlying dish, such that the outgoing liquid is protected from the steam stream. and it is not blown crosswise to the plate. Notably, the extended length of the upstream downstream duct 48, in combination with the decreased cross-sectional area of the discharge outlets 60 and 62 allows the outgoing liquid to be provided directly over a liquid receiving area, without drilling, over the inlet end 42 of the cover 40 of the underlying plate, thereby reducing the opportunity for the liquid to decrease the flow of the vapor and cause the liquid to sweep through the liquid cover. The inclination of the upstream duct entrance wall 54 also causes the liquid to be discharged with a substantial momentum vector (or momentum) in the direction of the downstream duct 50 instead of directly on the duct 40 cover. plate. This directional discharge allows mixing of the liquid discharged from both downcomers and can form a curtain of liquid that protects the discharge outlet 62 from the downcomer downstream of the undesirable vapor inlet, particularly under low liquid flow conditions. It can be appreciated that when the entrance walls 53a and 54 of the downcomer are inclined at the same angle, only the discharge outlet 62 of the downstream downcomer will have a smaller cross-sectional area than its upper entrance 58, but the total area of both outlets 60 and 62 will however be less than the total area of the inlets 56 and 58. Preferably, however, the angle of inclination of the upstream duct entrance wall 54 is greater than the inlet wall 53a of the downstream duct, such that the outlet 60 of the upstream duct has a smaller cross-sectional area than its inlet 56. This reduction in cross-sectional area for the downstream duct provides the further advantage of throttling the downstream flow of the liquid through the upstream downstream conduit 48 to facilitate the accumulation of liquid within the downstream conduit. The inlet walls 53a and 54 of the downcomer can be flat as illustrated in Figures 4-6, semi-conical as shown in Figure 7, multi-segmented bends or cordals as shown in Figure 8. Other configurations and combinations are possible. , such as a wall 53a of the vertical planar downstream duct and a wall 54 of the inclined flat upstream duct. This is contemplated and within the scope of the invention.

If desired, an optional perforated plate 64 can close the discharge outlet 60 of the downstream downstream conduit 50, as shown in Figure 6. The plate 64 can be perforated with holes 66, openings, slots, directional openings and other desired characteristics. Alternatively, the plate 64 may comprise a plurality of overlapping plate segments that form a plurality of discharge openings in the spacing between the plate segments. As shown in Figures 6 and 7, an optional L-shaped bell or deflector 68 extending downwardly below the discharge outlet 60 of the upstream downcomer may be provided if desired. A horizontally extending portion 70 of the baffle 68 is aligned with the discharge outlet 60 and is dimensioned to deflect the moment (momentum) vertically downward from a substantial portion or all of the liquid exiting the discharge outlet 60. By diverting the liquid that falls in this manner, the force with which the liquid hits the plate below is reduced and the liquid is less likely to be swept through the vapor openings at that point on the cover of the liquid. plate. A vertically extending portion 72 of the baffle 68 is positioned to shield the liquid discharged from the prevailing steam flow and thereby reduce the opportunity for the steam to blow the liquid through the plate and deviate from the steam interaction throughout. of portions of the dish cover. The vertical portion 72 can be positioned between the discharge outlets 60 and 62 and can be formed by a downward extension of the dividing wall or partition wall 52. Alternatively, the vertical portion 72 of the deflector 68 can be placed on the opposite side. of the outlet 60 and can be formed by a downward extension of the inlet wall 54 of the downstream duct. It will be appreciated that the objectives of shielding the liquid discharged from the vapor flow and altering the downward momentum (momentum) of the discharged liquid can be obtained by using defl ectors of curved, muti-segmented or other shapes in place of the deflector at L shape illustrated in Figures 6 and 7. Further, vertical portion 72 of baffle 68 could be omitted, such as in those applications where discharge outlet 60 is sufficiently close to cover 40 of the underlying dish, such so that the liquid is discharged directly into the liquid stream flowing from the discharge outlet 62 of the downstream downcomer. The horizontal portion 70 of the baffle 68 could also be formed separately from the vertical portion 72 and be supported by clamps attached to the shell or cover 30 of the column, the cover 40 of the underlying plate or other internal components. The above variations are contemplated by and within the scope of the present invention. An overflow 74 separates the inlets 56 and 58 of the downcomer and causes the liquid to fill the upstream downstream duct 48 and accumulate to a selected depth on the dish deck 40, before it spills from the overflow and enters the downstream duct down 50. Alternatively, the overflow 74 could be omitted or positioned at the edge of the outlet end 44 of the deck 4r0 of the tray, so that the liquid should be spilled over the overflow to enter the inlet 56 of the downcomer stream up 48. In addition, two overflows 74 could be used, one positioned at the edge of the outlet end 44 of the cover 40 of the tray and the other positioned between the inlets 56 and 58 of the descending duct. In a further variation, holes (not shown) can be placed in the partition wall 52 to allow a portion of the liquid in the upstream downflow 48 to flow to the downstream downstream 50. In service, the liquid flows from the inlet end 42 to the outlet end 44 of the cover 40 of the tray and at least a first part of the liquid enters through the inlet 56 of the upstream downflow 48. At least some of the first part of the liquid is transported down through the upstream duct and is discharged through outlet 60 onto the cover of the underlying plate. Advantageously, the liquid is discharged with a significant momentum vector (momentum) in the direction of the downstream duct to facilitate mixing of the liquid, reducing the momentum (momentum) of the liquid downward and shielding or shielding the outlet 62 discharge of the downcomer downstream of the steam inlet. Optionally, some of the first part of the liquid in the downstream duct 48 passes through the holes (not shown) and enters the downstream duct 50 for passage down therethrough and discharges onto the cover of the underlying dish. When the flow rates of the liquid increase to a sufficient level, the overflow 74 causes the liquid to accumulate on the dish cover and a second part of the liquid finally flows over the overflow 74 and enters the downstream duct. As the liquid accumulates and flows through the plate cover 40, steam passes up through the openings 47 in the plate cover and interacts with the liquid on the plate cover. It can be seen that the downstream upward sloping pipe 48 provides greater area above the plate for vapor flow and vapor-liquid interaction than would be available if it were extended vertically downward. Because the upstream duct 48 extends downwardly to the level of the liquid on the underlying tray, it is capable of shielding the liquid in the downstream duct 48 upstream, so that the steam flow does not eject the liquid discharged from the duct. the cover 40 of the plate and thereby interferes with the desired vapor-liquid interaction in the plate cover. In addition, the inclined entrance wall 54 alters the momentum (momentum) downstream of the liquid and provides a backward momentum (amount of movement) to reduce the incidence of liquid being swept through the flow openings. of steam on the dish cover as a result of such a moment (or amount of movement) backwards and to create a curtain of liquid that prevents steam from entering the downstream downstream conduit 50. In addition, the outlet 60 of restricted discharge allows the liquid accumulates inside the upstream downstream duct 48 and passes through the optional holes (not shown) or flows over the overflow 74 and enters the downstream downstream duct 50, thereby facilitating the liquid seal necessary to resist the steam flow up through the downstream duct. While the invention has been described with respect to a single-pass plate, the invention can be easily adapted for use with multi-step plates as illustrated in FIG. 9, where the central down conduit portion is shown. of a two-step dish. This is contemplated by and is within the scope of the invention. It will be appreciated, of course, that the downcomer of the present invention may be used in combination with other features of the dish, such as a raised liquid receiving area and / or lights or other openings for vapor flow to limit, as long as the allows the flow of steam through the liquid receiving area. From the foregoing, it will be seen that this invention is adapted to obtain all the aims and objectives summarized hereinabove together with other advantages that are inherent in the structure. It will be understood that certain characteristics and subcombinations are useful and can be used without reference to other characteristics and subcombinations. This is contemplated by and is within the scope of the claims. It is noted that, regarding this date, the best method known by the applicant to carry out the aforementioned invention is that which is clear from the present description of the invention.

Claims (24)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. A steam-liquid contact plate characterized in that it comprises: a cover of the plate having at least one opening for removing liquid from a surface top of the plate cover and a plurality of openings to allow steam to flow up through the plate cover to interact with the liquid on the upper surface; at least one downstream duct extending downwardly in the opening in the dish cover and having an inlet at an upper end for receiving at least a portion of the liquid entering the opening from the dish cover and a lower discharge outlet through which at least part of the liquid portion leaves the downstream conduit; a downstream duct extending downwardly in the opening in the dish cover and having a lower discharge outlet through which a second portion of the liquid leaves the downstream duct; a dividing wall or partitioning wall separating the downcomer downstream of the downcomer upstream along at least a portion of the length of downcomers downstream and upstream and an inlet wall defining a portion of the Downstream duct upstream, the inlet wall is inclined downward toward the divider wall and the divider wall is tilted downwards in the same general direction as the inlet wall. The steam-liquid contact plate according to claim 1, characterized in that the dividing wall or partition wall forms at least a portion of an inlet wall of the downstream duct. 3. The steam-liquid contact plate according to claim 2, characterized in that the downstream downstream duct includes an upper inlet in the opening in the dish cover and in which an overflow is positioned in the opening and separates the ducts. inputs for the downstream conduits upstream and downstream. 4. The steam-liquid contact plate according to claim 1, characterized in that the inlet wall of the downstream duct is selected from the group consisting of flat, curved, semi-conical and multi-segmented cordales. 5. The steam-liquid contact plate according to claim 1, characterized in that the inlet wall of the downstream duct is selected from the group consisting of flat, curved, semi-conical and multi-segmented cordales. The vapor-liquid contact plate according to claim 5, characterized in that the lower discharge outlet of the downstream downstream duct is positioned above the lower discharge outlet of the downstream duct. The steam-liquid contact plate according to claim 1, characterized in that it includes a second upstream downstream duct positioned in the opening on one side of the downstream downstream duct of the first mentioned upstream downstream duct and wherein a second The dividing wall separates the downstream duct downstream of the second downstream duct upstream along at least a portion of its lengths. The vapor-liquid contact plate according to claim 1, characterized in that it includes at least one plate containing openings for the flow of the liquid positioned in the lower discharge outlet of the downstream duct upstream and / or downstream. 9. A mass transfer column characterized in that it comprises: an outer shell or shell defining an interior region open to the flow of vapor and liquid streams and a plurality of plates arranged generally horizontally and vertically spaced apart positioned in the region open inside to facilitate contact between vapor and liquid as they flow into the inner region of the column, at least one of the plates comprises: a cover of the plate having at least one opening for removing the liquid from an upper surface of the plate cover, a plurality of openings to allow steam to flow upwards through . the plate cover to interact with the liquid on the upper surface and an inlet area to receive the liquid from above the plate cover; at least one downstream duct extending downwardly in the opening in the dish cover and having an inlet at an upper end for receiving at least a first portion of the liquid entering the opening from the dish cover and a lower discharge outlet through which at least part of the first portion of the liquid leaves the downstream conduit; a downstream duct extending downwardly in the opening in the dish cover and having a lower discharge outlet through which a second portion of the liquid leaves the downstream duct downstream of the inlet area of a cover of the underlying plate, the lower discharge outlet of the downstream downstream duct is positioned above the lower discharge outlet of the downstream duct, a dividing wall or partition wall separating the downstream duct downstream of the upstream downstream duct along at least a portion of the length of the downstream and downstream conduits and an inlet wall defining a portion of the downstream conduit, the. Entrance wall is tilted down towards the dividing wall. The mass transfer column according to claim 9, characterized in that the discharge outlet of the downstream duct is positioned in such a way that the at least part of the first portion of the liquid exits over the inlet area of the duct. the cover of the underlying plate. The mass transfer column according to claim 10, characterized in that the entrance area of the cover of the underlying plate does not contain such openings. 12. The mass transfer column according to claim 9, characterized in that the second portion of the liquid exiting the downstream downstream conduit includes another part of the first portion of the liquid that enters the opening in the dish cover. The mass transfer column according to claim 9, characterized in that it includes at least one baffle positioned below the discharge outlet of the downstream conduit to divert the moment (moment of movement) downwards from the less part of the first portion of the liquid that comes out of the discharge outlet. The mass transfer column according to claim 9, characterized in that the dividing wall slopes downwards in the same general direction as the entrance wall. 15. The mass transfer column according to claim 9, characterized in that the dividing wall forms at least a portion of an inlet wall of the downstream duct and slopes downwards in the same general direction as the wall of the duct. entry. 16. The mass transfer column according to claim 15, characterized in that the downstream downstream duct includes an upper inlet in the opening in the dish cover and in which an overflow is positioned in the opening and separates the inlets for the downward ducts upstream and downstream. 17. The mass transfer column according to claim 16, characterized in that the inlet wall of the downstream duct is selected from the group consisting of planar, curved, semi-conical and multi-segmented cordales. 18. The mass transfer column according to claim 17, characterized in that the inlet wall of the downstream downcomer is selected from the group consisting of planar, curved, semi-conical and multi-segmented cordales. 19. The mass transfer column according to claim 9, characterized in that it includes a second upstream downstream duct positioned in the opening on one side of the downstream duct opposite to the first upstream duct mentioned above and wherein a second wall The divider separates the downcomer downstream of the downcomer upstream along at least a portion of its lengths. - 20. The bulk transfer column according to claim 9, characterized in that it includes at least one plate containing openings for the flow of liquid positioned in the lower discharge outlet of the downstream duct upstream and / or downstream. 21. A method for intermixing vapor and liquid streams in a mass transfer column containing a plurality of vertically spaced vapor-liquid contact plates, at least one of the plates having a plate cover containing openings or holes and an upstream downstream duct and a downstream downward duct positioned in an opening in the dish cover, the upstream downstream duct is separated from the downstream downstream duct by a divider wall extending along at least one portion of the length of the downstream conduits upstream and downstream, the upstream downstream conduit has an inlet wall inclined downwardly in a direction downstream downstream and the divider wall is inclined downward in the same general direction as the entrance wall, the method is characterized in that it comprises the step of: (a) flowing a stream of liquid through the dish cover into the opening; (b) directing at least a first part of the liquid stream from the plate cover to an inlet in the downstream conduit upstream in the opening and passing at least some of the first part of the liquid stream downwards through the upstream duct; (c) discharging at least some of the first part of the liquid stream from the downstream duct up through a discharge outlet in the downstream duct direction; (d) directing a second part of the liquid stream of the dish cover or some of the first part of the downstream duct stream liquid, al. downstream duct and downstream through the downstream duct and (e) passing the vapor upstream through the openings in the dish cover and interacting the vapor stream with the liquid stream on the cover of the plate. 22. The method according to claim 21, characterized in that it includes causing the liquid stream to accumulate on the dish cover when placing an overflow in said opening. 23. The method according to claim 21, characterized in that it includes accumulating a portion of the at least some of the first part of the liquid stream in the downstream duct to form a liquid seal to prevent upward entry of the vapor through the discharge output. The method according to claim 23, characterized in that it includes accumulating a portion of the second part of the liquid stream of the plate cover or a portion of something of the first part of the stream of the upstream conduit liquid. , in the downstream conduit downstream to form a liquid seal to prevent upstream steam entering the downstream downstream conduit.