Patent Description:
Separation devices, such as mass transfer columns, are employed for an intensive gas-liquid or liquid-liquid contact in a wide variety of processes, such as in particular absorption, stripping, scrubbing, distillation, extraction and the like. Distillation columns, for example, are designed to separate a specific substance from a liquid mixture comprising two or more substances by selective evaporation and condensation. For this purpose, distillation columns comprise a boiler at the bottom and a condenser at the top so that during the operation vapour rises upwardly and liquid descends so as to enable a gas-liquid contact for effecting the mass transfer between both phases. The substance with the higher boiling point will concentrate in the liquid phase, wherein the substance with the lower boiling point will concentrate in the gas phase. In order to achieve an intensive gas-liquid contact, such columns are typically filled with an internal to optimize the gas-liquid mass transfer. Examples for such an internal are trays and packings, for instance random packings and structured packings, such as in particular a packing with cross channel structure. An essential requirement for an optimal mass transfer between both phases is that liquid is uniformly distributed over the cross-section of the tray or packing, respectively. Moreover, it is further important in particular for packing columns, i.e. columns including a random or structured packing, that the liquid flows on the surface of the packing as a thin film so as to maximize the contact area and contact time between the liquid phase and the gas phase. For both aforementioned purposes, usually liquid distributors are provided at the top of the packing or each of the packing layers, respectively. Such liquid distributors are also used in certain reactor, such as for distributing liquid above a catalyst bed of a reactor.

Liquid distributors usually comprise one or more pre-distributor members and a plurality of distributor members, which are arranged below the one or more pre-distributor members. Pre-distributor members are also denoted in this technical field as parting boxes. Typically, the pre-distributor members as well as the distributor members have the form of a trough comprising two side walls, two front walls and one or more bottom walls. The top surface of the trough being opposite of the one or more bottom walls may be closed by providing a top wall or may be open. The troughs of the one or more pre-distributor members comprise each a plurality of discharge openings in their bottom walls, whereas the troughs of the distributor members typically comprise each a plurality of discharge openings in their bottom walls, in their side walls or in their bottom walls as well as in their side walls. While the one or more pre-distributor members are arranged in one plane in parallel to each other, the distributor members are arranged in the plane below that of the pre-distributor members in parallel to each other, wherein the length axes of the distributor members are perpendicular to those of the pre-distributor members. The one or more pre-distributor members and the distributor members are arranged so that the discharge openings of the one or more pre-distributor members are above the open or closed top surfaces of the distributor members. The number of distributor members is much higher than that of the pre-distributor members, because each of the one or more pre-distributor members distributes liquid to a plurality, usually dozens of distributor members. More specifically, during the operation of a liquid distributor, liquid flows through an inlet of the liquid distributor into a feed line of the one or more pre-distributor member, wherein the feed line may or may not separate into two or more further lines, each of which leading to the one or more pre-distributor members for instance through their open or closed top surfaces. The liquid fed via the feed lines into the one or more pre-distributor members remains there for a certain residence time, before it is discharged via the discharge openings arranged in the bottom walls of the one or more pre-distributor members into the distributor members via their open or closed top surfaces. If the top surfaces of the distributor members are closed each by a top wall, the top walls comprise respective openings allowing the liquid discharged from the corresponding pre-distributor members through their discharge openings into the distributor members. Each of the distributor members distributes the liquid via its discharge openings. The liquid may be discharged directly onto the surface of the packing or packing layer, respectively, which is located closely underneath the distributor members, or the liquid might be deflected using guiding elements, before the liquid drops onto the surface of the packing or packing layer, respectively. For instance, each of the distributor members may distributes the liquid via its discharge openings in the form of jets. In order to form a thin liquid film, one or more deflectors or so-called screens, respectively, in the form of specifically formed guide walls may be arranged in front of (or ahead, respectively) the discharge openings of the distributor members, onto which the liquid jets impinge in a specific impact angle so as to avoid at least substantially the formation of splashes of small liquid drops at the site of impact on the screen. In tendency, the impact angle of the liquid onto the screen should be small in order to avoid such a splashing. The liquid film, which is formed on the screen surface, flows down the screen surface to the lower end of the screen, which forms a drip edge, from which the liquid falls down in form of liquid drops onto the surface of the packing or packing layer, respectively, which is located closely underneath the drip edge of the screen. Also known are respective liquid distributors, which comprise two groups of distributor members, wherein each distributor member of the first group is connected with a distributor member of the second group so that liquid flows from each of the distributor member of the first group to a distributor member of the second group, from which the liquid is discharged via their discharge openings and deflected by screens as described above.

The aforementioned liquid distributors are particularly suitable for operating ranges of <NUM> to <NUM>, with the operating range being the quotient of the maximal liquid load divided by the minimal liquid load. This is due to the fact that a minimum liquid height is required in the pre-distributor members in order to assure a homogenous distribution of the liquid across the cross-section of the pre-distributor members limiting the cross-sectional area of the trough in case of low liquid flow. Furthermore, because the liquid height in the trough at a given cross-sectional area is proportional to the square of the liquid load, the upper possible liquid load in the pre-distributor members is also limited, because the possible maximal height of a pre-distributor member is restricted by the dimensions of the manway, through which the pre-distributor member has to be moved during the installation of the liquid distributor in the separation device. In order to increase the operating range, the height of a pre-distributor member may be increased correspondingly. However, then the pre-distributor member gets so heavy that it cannot be moved anymore via a person through the manway of a separation device, such as a distillation column, and installed therein. Moreover, the dimensions and in particular height of such an enlarged pre-distributor member would be too big for the man-ways of typical size provided in separation devices. Therefore, if a broader operating range is needed, in practice each of the one or more pre-distributor members of a liquid distributor is provided with a dividing wall extending along the length axis of the pre-distributor member so that the pre-distributor member is multistage or a two-chamber member, respectively. The dividing wall allows liquid to flow from the first chamber of the pre-distributor member over the dividing wall into the second chamber of the pre-distributor member, when a certain liquid level is reached in the first chamber. For this purpose, the dividing wall may have a lower height than the side walls of the pre-distributor member so that the dividing wall forms an overflow edge. Alternatively, the dividing wall may comprise in its upper part one or more slits, holes or differently formed openings, which allow liquid to flow from the first chamber through the overflow opening(s) into the second chamber of the pre-distributor member. Thereby, in the case of low liquid load only one chamber operates, whereas in the case of a higher liquid load both chambers operate or be filled with liquid, respectively, thus allowing the pre-distributor member to be operated over a broad operating range of <NUM> to up to ten. In alternative applications, each of the aforementioned pre-distribution members having a dividing wall may be operated with two different liquids, wherein the first liquid is exclusively fed via a first inlet into the first chamber of the pre-distributor member, whereas the second liquid is exclusively fed via a second inlet into the second chamber of the pre-distributor member. During the operation it is assured that none of both liquids flow over the dividing wall. However, the pre-distributor members with such dividing walls have several disadvantages. Firstly, the dividing wall has to be fixed in the trough of such a pre-distributor member by means of seal welding, in order to reliably achieve even over a long operation time that liquid flows from the first to the second chamber of the pre-distributor member exclusively via the overflow edge or overflow opening(s), respectively. However, seal welding leads to a significant welding heat impact and requires special welding equipment. Secondly, since such a pre-distributor member has to be moved during the installation in the mass transfer column through a manway, it is limited concerning its maximum width and maximum height, which in turn limits the upper end of the operating range. Thirdly, because such a pre-distributor member is a single piece-trough, it has a quite high weight, if it exploits the maximum possible dimensions allowed by the dimensions of the manway, which hampers its installation.

<CIT> discloses a liquid distributor comprising a distributor box and below thereof several distributor tubes, wherein each distributor tube comprises a primary chamber and two or more secondary chambers, with each of the chambers comprising one or more bottom openings.

<CIT> relates to an upper trough and a lower trough, with the upper trough comprising holes and with a plate being arranged outside upper trough.

In view of this, the object underlying the present invention is to provide a liquid distributor for a mass transfer column, in particular for a packing column of the type comprising one or more pre-distributor members and a plurality of distributor members, wherein the one or more pre-distributor members do not need dividing walls being fixed by seal welding into the pre-distributor member(s), wherein the liquid distributor and particularly the one or more pre-distributor members may nevertheless be operated over a broad operating range and even over a broader operating range than the known seal welded multistage pre-distributor members, and wherein the one or more pre-distributor members may be nevertheless easily installed with larger dimensions than the known multistage pre-distributor members even through the manway of a typical size.

This object is satisfied in accordance with the present patent application by providing a liquid distributor for a separation device, such as for a mass transfer column in particular for a packing column for absorption, stripping, scrubbing or distillation, or for reactor, such as for distributing liquid above a catalyst bed of a reactor, wherein the liquid distributor comprises at least one pre-distributor member and a plurality of distributor members, wherein the at least one pre-distributor member is positioned above the plurality of distributor members, wherein the at least one pre-distributor member comprises at least two troughs, which each comprise a plurality of discharge openings, wherein each two of the at least two troughs are connected with each other, wherein a first of the at least two troughs has an overflow means and at least one deflector attached to the overflow means or the side wall of the first of the at least two troughs, wherein a second of the at least two troughs has an upper edge, wherein at least one deflector attached to the overflow means or the side wall of the first trough extends from above the upper edge of the second trough to the second trough so that liquid flows from the first trough over the overflow means and the at least one deflector into the second trough, if the liquid level in the first trough reaches the overflow means, wherein the distributor members comprise a first group of distributor members being arranged at least substantially in parallel to each other, which have the form of a hollow box having two side walls, two front walls and a bottom wall being connected with each other, wherein the bottom wall(s) and/or one of the side walls has a plurality of discharge openings, wherein the top surface being opposite to the bottom wall is open and arranged so that liquid flowing through the plurality of discharge openings of the at least two troughs of the pre-distributor member flows through the top surface into the distributor members of the first group.

By replacing in a liquid distributor the known seal welded multistage pre-distributor member, i.e. a trough with a dividing wall being fixed along the length axis of the trough so as to divide the trough into two halves (or chambers respectively), with a pre-distributor member comprising at least two (separate) troughs, which are connected with each other, for instance with their side walls, so that liquid flows from the first trough over the overflow means and the at least one deflector into the second trough, if the liquid level in the first trough reaches the overflow means, the troughs do not need anymore to be provided with a dividing wall being fixed by seal welding therein. On the contrary, it is simply necessary to connect the troughs for instance via their side walls, which may be easily achieved by screwing, riveting, clamping or any other mechanical connection method, or by simple spot welding so that no or at most minimal welding heat impact is applied and no or, if at all, only simple welding equipment is required. This is due to the fact that on account of the overflow means and the at least one deflector connected thereto and extending into the second trough, liquid flows reliably and completely without any liquid loss from the first trough over the overflow means and the at least one deflector into the second trough, even if there should be a small gap being present between both troughs, because the one deflector extends into the second trough and thus over the possible small gap. Furthermore, because the pre-distributor member comprises two separate troughs, which may be easily connected with each other, any of the two troughs may have the same dimensions as the whole seal welded multistage pre-distributor member of the prior art, so that the pre-distributor member of the present invention may have a two-fold or even higher-fold width than the seal welded multistage pre-distributor member of the prior art. This is due to the fact that the two, three, four or even more troughs of the pre-distributor member in accordance with the present invention may be separately from each other moved through the manway of the separation device and then connected therein. On account of the possibility of achieving a higher width, the pre-distributor member in accordance with the present invention may be designed for an even broader operating range and thus may be operated at even higher liquid loads than the known seal welded multistage pre-distributor members of the prior art. Moreover, because the troughs of the pre-distributor member in accordance with the present invention may be separately from each other moved through the manway of the separating, they may be designed to have each a comparable low weight so as to be easily transported, wherein by combining a sufficient high number of troughs with each other to one pre-distributor member nevertheless a comparable high operating range may be covered. Thus, also the installation flexibility is improved by using the pre-distributor members in accordance with the present invention.

The feature, according to which at least one deflector attached to the overflow means or the side wall of the first trough extends from above the upper edge of the second trough to the second trough means in accordance with the present invention that the at least one deflector extends to span at least from the overflow means along the direction towards the adjacent second deflector and ends above the second trough above the top surface of the second trough or in the second trough in the top surface of the second trough or in the second trough below the top surface of the second trough.

Furthermore, the feature "so that liquid flows from the first trough over the overflow means and the at least one deflector" means that the overflow means and the deflector are so arranged that the liquid distributor is suitable to be operated so that "liquid flows from the first trough over the overflow means and the at least one deflector". Thus, this feature does not require that such a flow is realized under any possible operation conditions, but it is sufficient that it is achievable by using appropriate operation conditions. Preferably, at least one deflector attached to the overflow means or the side wall of the first trough extends from above the upper edge of the second trough to or above the second trough so that liquid flows from the first trough over the top surface of the overflow means and the at least one deflector into the second trough, if the liquid level in the first trough reaches the overflow means.

In accordance with the present invention, the at least one pre-distributor member of the liquid distributor comprises at least two troughs, which each comprise a plurality of discharge openings. Preferably, at least two and more preferably all of the at least two troughs comprise each two side walls, wherein preferably two adjacent troughs of the pre-distributor member contact each other and are connected with each other via their side walls. Thus, the side walls of the two adjacent troughs, by which the two adjacent troughs contact each other and are connected with each, are separate side walls, which may be separated from each other. Preferably, at least the side walls of the troughs contacting each other or more preferably all side walls of the troughs have at least substantially the same length and width and the troughs contacting each other are arranged so that both side walls contact each other over their whole area. Contacting means that they are close together, which does not exclude that a small gap of a few micrometer or millimeter is present. Preferably, the gap, if present, amounts from <NUM> to <NUM>, more preferably from <NUM> to <NUM> and even more preferably from <NUM> to <NUM>, wherein gap means the distance between the two side walls. As set out above, adjacent troughs may be connected with each other by screwing, riveting, clamping or any other mechanical connection method, or by simple spot welding.

In a further development of the idea of the present invention, it is proposed the at least two and more preferably all of the at least two troughs comprise each a bottom wall, wherein the bottom wall comprises the plurality of discharge openings. Moreover, further discharge openings may be located in one or more of the side walls of the at least two troughs. Preferably, the bottom walls of at least the first and second trough are flat and are essentially aligned with each other, wherein essentially aligned with each other means that the bottom wall of the second trough is in the same plane as the bottom wall of the first trough or in a plane being not more than <NUM>% and preferably not more than <NUM>% of the height of the highest sidewall of the first trough below or above the plane of the bottom wall of the first trough.

In accordance with a further preferred embodiment of the present invention, anyone of at least the first trough and of the second trough and preferably all of them has/have the form of a hollow box having two side walls, two front walls and a bottom wall being connected with each other, wherein the bottom wall has a plurality of discharge openings. All walls are fluid tightly connected with each other, so that liquid can leave the troughs only through the plurality of discharge openings. It is further preferred that the bottom walls of two adjacent troughs are at least substantially aligned with each other. The top surface being opposite to the bottom wall of each of the troughs may be closed by a top wall comprising one or more openings for feeding the liquid into the troughs or, preferably, is open. Adjacent troughs may have the same width or may have a different width.

The present invention is not particularly limited concerning the cross-sectional form of the troughs or hollow boxes, respectively. For instance, the hollow boxes may have, independently from each other, a square, rectangular, trapezoidal, oval, polygonal or irregular cross-section. However, good results are in particular obtained, when each hollow box has a square or rectangular cross-section.

Preferably, none of the troughs of the pre-distributor means comprises an internal dividing wall and in particular no seal welded internal dividing wall.

Concerning the form of the overflow means, the present invention is not particularly restricted. For example, the overflow means may comprise one or more selected from the group consisting of overflow edges, overflow slits, overflow holes and arbitrary combinations of two or more thereof.

In accordance with a first particular preferred embodiment of the present invention, the overflow means of the first trough of the pre-distributor member of the liquid distributor comprises one or more overflow edge or even consists of one or more overflow edges. This may be easily accomplished by providing the two side walls of the first trough so that one is higher than the other of the two side walls, wherein the (one) overflow edge is the upper edge of the lower side wall. Preferably, the at least one deflector being attached to the overflow edge or the side wall of the first trough extends at an angle of more than <NUM>° to less than <NUM>° and preferably between <NUM>° and <NUM>° from the lower side wall of the first trough to the second trough. In this connection, <NUM>° corresponds to the plane through lower side wall and <NUM>° corresponds to the plane being perpendicular to the plane of the lower side wall. Consequently, in this embodiment the first trough has a larger height than the second trough.

Good results are particularly obtained in this embodiment, when the overflow edge (i.e. preferably the upper edge of the lower side wall) is at a height corresponding to <NUM> to <NUM>%, preferably <NUM> to <NUM>% and more preferably <NUM> to <NUM>% of height the height of the higher side wall. Moreover, it is preferred in this embodiment that the upper edge of side wall of the second trough being connected with the side wall of the first trough comprising or forming the overflow edge has about the same height than the overflow edge or <NUM>% to less than <NUM>% of the height of the overflow edge.

In a further development of the idea of the present invention, it is suggested that the first trough has one deflector, which is attached to the overflow edge or the side wall and extends over at least <NUM>%, preferably at least <NUM>%, more preferably at least <NUM>%, even more preferably at least <NUM>% and most preferably <NUM>% of the length of the overflow edge. This reliably allows that liquid flows homogeneously over the whole width of the overflow edge from the first trough into the second trough. Depending on the width and the angle, with which the at least one deflector attached to the overflow means or the side wall extends from above the upper edge of the second trough to the second trough, the at least one deflector ends in or above the second trough above the top surface of the second trough or in the top surface of the second trough or below the top surface of the second trough.

In accordance with an alternative variant of this embodiment, the overflow edge and the at least one deflector are formed by bending one of both side walls of the first trough so as to form an overflow edge and a deflector being integrally connected with the overflow edge and preferably extending at an angle of more than <NUM>° to less than <NUM>° and more preferably between <NUM>° and <NUM>° from the side wall to the second trough.

In accordance with a second particular preferred embodiment of the present invention, the overflow means of the first trough of the pre-distributor member of the liquid distributor comprises one or more and preferably several overflow slits. The overflow slits are preferably provided in the upper part of one of the side walls of the first trough, wherein at least one deflector is attached to the overflow means or the side wall so that liquid flowing through the overflow slits flows over the top surface of the at least one deflector, and wherein preferably the at least one deflector extends at an angle of more than <NUM>° to less than <NUM>° and preferably between <NUM>° and <NUM>° from the side wall provided with the overflow slits of the first trough to the second trough. In this embodiment, both side walls of the first trough may have the same size or a different size. For instance, the side wall of the first trough which comprises the slit(s) is lower than the other side wall.

In this embodiment, the overflow slits preferably extend from the upper edge of one of the side walls of the first trough substantially vertically downwards (i.e. the longitudinal side of the slits are oriented vertically), wherein preferably the slits extend from the upper edge of one of the side walls vertically downwards for <NUM> to <NUM> and more preferably for <NUM> to <NUM>. The upper ends of the slits may be positioned at the upper edge of the side wall so that the slits are at their top not surrounded by the side wall, or the upper ends of the slits may be positioned below the upper edge of the side wall so that the slits are completely surrounded by the side wall.

In particular in the case that the upper ends of the slits are positioned at the upper edge of the side wall so that the slits are at their top not surrounded by the side wall, the aforementioned first preferred embodiment relating to the overflow edge is combined with the second preferred embodiment relating to the overflow slits. In other words, in this variant the first trough comprises overflow slits and several overflow edges, namely those parts of the upper edge of the side wall, in which the overflow slits are present, which are interrupted by the slits. If the liquid flow is high enough, the liquid does not only flow through the overflow slits, but also over the overflow edges. That part of the side wall of the first trough, which covers the overflow edge(s) and the overflow slits, is the overflow means.

The at least one deflector is attached in this embodiment to the overflow means of the first trough at or below the lowermost point of all overflow slits.

In a further development of the idea of the present invention, it is suggested that the first trough has one deflector, which is attached to the overflow means or the side wall and extends over at least <NUM>%, preferably at least <NUM>%, more preferably at least <NUM>%, even more preferably at least <NUM>% and most preferably <NUM>% of the length of the side wall provided with the overflow slits of the first trough. This reliably allows that liquid flows homogeneously over the whole width of the overflow means from the first trough into the second trough. Depending on the width and the angle, with which the at least one deflector attached to the overflow means or the side wall extends from above the upper edge of the second trough to the second trough, the at least one deflector ends in or above the second trough above the top surface of the second trough or in the top surface of the second trough or below the top surface of the second trough.

In accordance with a third particular preferred embodiment of the present invention, the overflow means of the first trough of the pre-distributor member of the liquid distributor comprises one or more and preferably several overflow openings having another form than slits, such as having a circular, oval or elliptic cross-section. The preferred features described above for the overflow slits of the second embodiment are also preferred for the overflow openings of the third embodiment.

Preferably, the at least one deflector of the first trough of the pre-distributor means of the liquid distributor in accordance with the present invention extends from the overflow edge in the direction towards the adjacent second trough <NUM> to <NUM>% and preferably <NUM> to <NUM>% over the width of the second trough. The direction towards the adjacent second trough is the direction of a straight line extending perpendicular through all side walls of the first and second troughs.

Good results are in particular obtained, when the at least one deflector of the first trough extends from the overflow means in the direction towards the adjacent second trough for <NUM> to <NUM>.

In accordance with a further preferred embodiment of the present invention, the at least one pre-distributor member of the liquid distributor comprises three troughs, each of which comprising two side walls, wherein the first trough and the second trough contact each other and are connected with each other by each one of their side walls, and the second trough and the third trough contact each other and are connected with each other by each one of their side walls, wherein each of the first trough and the second trough has an overflow means and at least one deflector being attached to the overflow means or the side wall, wherein each of the second trough and the third trough has an upper edge, wherein at least one deflector attached to the overflow means or the side wall of the first trough extends from above the upper edge of the second trough to the second trough so that liquid flows from the first trough over the overflow means (preferably over the top surface of the overflow means) and the at least one deflector into the second trough, if the liquid level in the first trough reaches the overflow means, and wherein at least one deflector attached to the overflow means of the second trough extends from above the upper edge of the second trough to the third trough so that liquid flows from the second trough over the overflow edge and the at least one deflector into the third trough, if the liquid level in the second trough reaches the overflow means.

Each of the features mentioned above for the overflow means and the at least one deflector of the first trough is also preferred for the overflow means and the at least one deflector of the second trough. In particular, it is preferred that each of the deflectors of the first trough and of the second trough extends at an angle of more than <NUM>° to less than <NUM>° and preferably between <NUM>° and <NUM>° of the lower side wall of the respective trough.

In addition, it is preferred that the first trough has a larger height than the second trough and that the second trough has a larger height than the third trough. Height of a trough means the length of a straight line extending from the lowermost point and the uppermost point of the trough.

In accordance with a further development of the idea of the present invention, the pre-distributor member or, in the case of more than one pre-distributor member, at least one and more preferably all of the pre-distributor members comprise(s) four, five, six or even more troughs which are embodied and connected with each other analogous to the above described first trough, second trough and third trough.

In dependency of the diameter of the liquid distributor and the planned liquid load, it is preferred that the liquid distributor in accordance with the present invention comprises one to four pre-distributor members. Preferably, each of these pre-distributor members is designed as described above. If the liquid distributor comprises more than one pre-distributor member, it is preferred that all of the pre-distributor members are arranged at least substantially in parallel to each other and at least substantially in one plane. At least substantially parallel means that the longitudinal axes of adjacent troughs do not deviate from a parallel arrangement by more than <NUM>°, preferably by not more than <NUM>° and more preferably by not more than <NUM>°. At least substantially in one plane means that the bottom walls of the troughs do not deviate by more than <NUM>% of the height of the first trough from the plane spanned by the bottom wall of the first trough.

Furthermore, it is preferred that the distributor members are arranged adjacent to each other and at least substantially in one plane. At least substantially in one plane is defined for the distributor members in the same way as for the pre-distributor members.

The distributor members may be composed and arranged relative to each other as known in the prior art.

In accordance with the present invention, the distributor members comprise a first group of distributor members being arranged at least substantially in parallel to each other, which have the form of a hollow box having two side walls, two front walls and a bottom wall being connected with each other, wherein the bottom wall and/or one of the side walls has a plurality of discharge openings. It is preferred that the hollow box has a square or rectangular cross-section, but it may in principle also have a square, rectangular, trapezoidal, oval, polygonal or irregular cross-section. The top surfaces being opposite to the bottom are open. Each top surface of the distributor members is arranged so that liquid flowing through the plurality of discharge openings of the at least two troughs of the at least one pre-distributor member flows through the top surface into the distributor members of the first group. Good results are in particular obtained, when the bottom walls of the distributor members of the first group are at least substantially aligned with each other. In particular, the bottom walls of the distributor members of the first group may be arranged with their length axes at least substantially perpendicular to the length axes of the pre-distributor members.

If the liquid distributor only comprises distributor members of the first group, it is preferred that the plurality of discharge openings is provided in their side walls. However, they may in addition thereto comprise a plurality of discharge openings in their bottom wall(s) or instead of those in the side walls only in their bottom wall(s). Preferably, the liquid distributor comprises for each of the distributor members at least one screen which is arranged in front of the discharge openings of the corresponding distributor member so that a liquid jet outflowing through the discharge openings of each of the distributor members impinges onto the surface of the at least one screen and is deformed thereon to thin flowing liquid films. In particular, when the liquid distributor is designed for a packing column, it is preferred that the at least one screen is arranged so that it shields the discharge openings against a gas stream flowing upwardly.

In a further development of the idea of the present invention, it is suggested that the at least one screen is arranged in front of the discharge openings so that in the event of a maximum outflow of liquid, the liquid jets outflowing through the discharge openings of the distributor members of the second group impinge onto the surface of the at least one screen at angles of less than <NUM>°, preferably of less than <NUM>° and more preferably of less than <NUM>°. The angle is that between the direction of liquid jet outflowing through the discharge openings and the tangent at the point of the surface of the screen, where the liquid jet impinges.

Each of the at least one screen may have the shape of a sigmoidal curve in the vertical direction as well as in the jet-parallel section, wherein the sigmoidal curve is more preferably curved downwardly and/or has a largely constant curvature in the region in which the liquid jets impinge onto the surface of the at least one screen.

Preferably, the at least one screen is arranged in front of the discharge openings so that liquid jets outflowing through the discharge openings of the distributor members impinges onto the surface of the at least one screen essentially tangentially.

In accordance with an alternative embodiment of the present invention, the liquid distributor may comprise - in addition to the distributor members of the aforementioned first group - a second group of distributor members, which have the form of a hollow box having two side walls, two front walls and one or two bottom walls being connected with each other, wherein the bottom wall(s) and/or one of the side walls has/have a plurality of discharge openings for an outflow of liquid in the form of jets, wherein the top surface being opposite to the bottom wall is open or closed by a top wall and liquid flowing through the discharge openings of the distributor members of the first group flows through the top surface and/or through opening(s) of the top wall and/or through opening in the side walls of the distributor members of the second group into the distributor members of the second group.

Preferably, the liquid distributor comprises for each of the distributor members of the second group at least one screen which is more preferably arranged and designed as described above for the embodiment, in which the liquid distributor only comprises distributor members of the first group.

In accordance with still an alternative embodiment of the present invention, the liquid distributor may comprise instead of the aforementioned first and second groups of distributor members, distributor members each of which being provided with a dividing wall therein, thus separating the inner volume of the distributor member into a first and a second chamber. The distribution chamber may be a trough as described above, i.e. a trough comprising two side walls, two front walls and a bottom wall. The dividing wall located therein is preferably not connected with any deflection means. Discharge openings are provided in the bottom wall and/or in the side walls of both chambers of each distributor member. A liquid distributor with at least one pre-distributor member in accordance with the present invention and one or more of these distributor members is particularly suitable to be used in a reactor for distributing one or more liquids above a catalyst bed. Such a liquid distributor is in particular suitable for being used for individual liquid phase distribution onto one or more catalyst beds of a reactor. For instance, each of the two chambers of each distributor member is filed with a different liquid, wherein both liquids are distributed separately from each other through the discharge openings of the respective chambers of each distributor member onto the catalyst bed being arranged below thereof. For a regeneration or a cleaning of the distributor members, a cleaning liquid may be fed with increased load into one of the chambers of the distributor members so that the liquid does overflow from the respective chamber into the adjacent chamber of each distributor member.

In accordance with a further aspect, the present invention relates to a column for mass transfer, in particular for absorption, stripping, scrubbing or distillation, wherein the column includes at least one packing and at least one above described liquid distributor. Moreover, the present invention relates to a reactor including one or more catalyst beds and at least one above described liquid distributor for distributing liquid above the one or more catalyst beds.

In addition, the present invention relates to a method for separating at least two fluids, preferably for performing an absorption, stripping, scrubbing or distillation, wherein the method is performed with at least one aforementioned column. Furthermore, the present invention relates to method for distributing liquid and preferably two different liquids separately from each other above one or more catalyst beds of a reactor, wherein the method is performed with at least one aforementioned reactor.

In accordance with another particular preferred embodiment of the present invention, the liquid distributor only comprises distributor members, which are as described above for the second group of distributor members.

Subsequently, the present patent application is described by way of example with reference to advantageous embodiments and to the enclosed drawings.

The mass transfer column <NUM> shown in <FIG> comprises a packing <NUM> and a liquid distributor <NUM>. The liquid distributor <NUM> comprises a pre-distributor member <NUM> and several distributor members <NUM>. During the operation of the mass transfer column <NUM>, gas <NUM> ascends the mass transfer column <NUM>, passes around the distributor members <NUM> and is divided by the distributor members <NUM> into a plurality of partial gas streams <NUM>', <NUM>. Liquid <NUM> is fed into the liquid distributor <NUM> via a feed line <NUM> and is guided through the pre-distributor <NUM> into the distributor members <NUM>, from where it is drops down homogenously distributed onto the packing <NUM>.

The pre-distributor member <NUM> of a liquid distributor in accordance with the prior art shown in <FIG> is composed of a trough <NUM> and comprises a dividing wall <NUM> which is fixed to the trough <NUM> by seal welding, which extends along the length axis of the trough <NUM> and which divides the trough <NUM> into two chambers, namely a first chamber <NUM> and a second chamber <NUM>'. The dividing wall <NUM> comprises overflow slits <NUM>. If the liquid level reaches in one of the chambers <NUM>, <NUM>' of the trough <NUM> the lower end of the overflow slits <NUM>, liquid flows over the overflow slits <NUM> into the other chamber <NUM>, <NUM>' of the trough <NUM>. This seal welded multistage pre-distributor member <NUM> of the prior art has several disadvantages. Firstly, the dividing wall <NUM> has to be fixed in the trough <NUM> of such a pre-distributor member <NUM> by means of seal welding, in order to reliably achieve even over a long operation time that liquid flows from the first chamber <NUM> to the second chamber <NUM>' (or vice versa) of the pre-distributor member <NUM> exclusively via the overflow slits <NUM>. However, seal welding leads to a significant welding heat impact and requires special welding equipment. Secondly, since such a pre-distributor member <NUM> has to be moved during the installation in the mass transfer column <NUM> through a manway, it is limited concerning its maximum width and maximum height, which in turn limits the upper end of the operating range. Thirdly, because such a pre-distributor member <NUM> is a single piece-trough, it has a quite high weight, if it exploits the maximum possible dimensions allowed by the dimensions of the manway, which hampers its installation.

In order to overcome these drawbacks, the pre-distributor member <NUM> of a liquid distributor in accordance with one embodiment of the present invention as shown in <FIG> comprises two troughs <NUM>, <NUM>, namely a first trough <NUM> and a second trough <NUM>. <FIG> and <FIG> show schematically the pre-distributor member <NUM>, whereas <FIG> shows the liquid distributor <NUM> comprising the pre-distributor member <NUM> shown in <FIG> and <FIG> as well as the distributor members <NUM>. Each of the troughs <NUM>, <NUM> comprises two side walls <NUM>, <NUM>, a bottom wall <NUM> comprising a plurality of discharge openings <NUM> and two front walls <NUM>. The first trough <NUM> and the second trough <NUM> are connected with each other, for instance by riveting the second side wall <NUM> of the first trough <NUM> with the first side wall <NUM> of the second trough <NUM>. The top surface <NUM> of both troughs <NUM>, <NUM> is open. The second wall <NUM> of the first trough <NUM> is slightly lower than the first wall <NUM> and has several overflow slits <NUM>. Moreover, the upper edge <NUM> of the second wall <NUM> of the first trough <NUM>, which is interrupted by the overflow slits <NUM>, forms several overflow edges <NUM>. That part of the side wall <NUM> comprising the overflow edges <NUM> and the overflow slits <NUM> is the overflow means <NUM> of the first trough <NUM>. Slightly below the lower end of the overflow slits <NUM>, a deflector <NUM> is arranged, which is connected with the overflow means <NUM> formed by the second wall <NUM> of the first trough <NUM>. The deflector <NUM> extends at an angle of more about <NUM>° from the second side wall <NUM> of the first trough <NUM> to the second trough <NUM>. The first and second side walls <NUM>, <NUM> of the second trough <NUM> and thus also the upper edges <NUM>' of the side walls are lower than those of the first trough <NUM>.

During the operation, liquid flows from the feed line <NUM> as shown in <FIG> into the first trough <NUM> of the pre-distributor member <NUM>. A part of the liquid flows through the discharge openings <NUM> of the first trough <NUM> of the pre-distributor member <NUM> as shown in <FIG> and <FIG> into the troughs of the distributor members <NUM> as shown in <FIG> being arranged below the pre-distributor member <NUM>. If the liquid load is high enough, the liquid level within the first trough reaches the lower end of the slits <NUM> and, if it is even higher, possibly also the upper edge <NUM> or overflow edges <NUM>, respectively, of the first trough <NUM>. Another part of the liquid flows then through the overflow slits <NUM> and possibly also the upper edge <NUM> or overflow edges <NUM>, respectively, and from there over the deflector <NUM> into the second trough <NUM>. From there liquid flows through the discharge openings <NUM> of the second trough <NUM> of the pre-distributor member <NUM> into troughs of the distributor members <NUM> as shown in <FIG> being arranged below the pre-distributor member. On account of the avoidance of a seal welded dividing wall as in the prior art and as shown in <FIG>, the pre-distributor member <NUM> of the liquid distributor in accordance with the present invention is easily producible and is in particular with no or at most a minimal welding heat impact applied and no or, if at all, only simple welding equipment is required. This is due to the fact that on account of the overflow means <NUM> and the at least one deflector <NUM> connected thereto and extending into the second trough <NUM>, liquid flows reliably and completely without any liquid loss from the first trough <NUM> over the overflow means <NUM> and the at least one deflector <NUM> into the second trough <NUM>, even if there should be a small gap being present between both troughs <NUM>, <NUM>, because the one deflector <NUM> extends into the second trough <NUM> and thus over the possible small gap. Furthermore, because the pre-distributor member <NUM> comprises two separate troughs <NUM>, <NUM>, which may be easily connected within the separation device, each of the troughs <NUM>, <NUM> may have the same dimensions than the whole seal welded multistage pre-distributor member <NUM> of the prior art, so that the pre-distributor member <NUM> of the present invention may have a two-fold or even higher-fold width than the seal welded multistage pre-distributor member <NUM> of the prior art. On account of the possibility of achieving a higher width, the pre-distributor member <NUM> in accordance with the present invention may be designed for an even broader operating range and thus at even higher liquid loads than the known seal welded multistage pre-distributor members <NUM> of the prior art. Moreover, because the troughs <NUM>, <NUM> of the pre-distributor member <NUM> in accordance with the present invention may be separately from each other moved through the manway of the separating, they may be designed to have each a comparable low weight so as to be easily transported, wherein by combining a sufficient high number of troughs <NUM>, <NUM> with each other to one pre-distributor member <NUM> nevertheless a comparable high operating range may be covered.

The pre-distributor member schematically shown in <FIG> is similar to that described above with regard to <FIG>, but it comprises three troughs <NUM>, <NUM>, <NUM>. Each of the three troughs <NUM>, <NUM>, <NUM> comprises two side walls <NUM>, <NUM>, wherein the first trough <NUM> and the second trough <NUM> contact each other and are connected with each other by each one of their side walls <NUM>, <NUM>, and the second trough <NUM> and the third trough <NUM> contact each other and are connected with each other by each one of their side walls <NUM>, <NUM>, wherein each of the first trough <NUM> and the second trough <NUM> has an overflow means <NUM> and at least one deflector <NUM> being attached to the overflow means <NUM>. Each of the second trough <NUM> and the third trough <NUM> has an upper edge <NUM>, <NUM>', wherein at least one deflector <NUM> attached to the overflow means <NUM> of the first trough <NUM> extends from above the upper edge of the second trough <NUM> to the second trough <NUM> so that liquid flows from the first trough <NUM> over the overflow means <NUM> and the at least one deflector <NUM> into the second trough <NUM>, if the liquid level in the first trough <NUM> reaches the overflow means <NUM>, and wherein at least one deflector <NUM> attached to the overflow means <NUM> of the second trough <NUM> extends from above the upper edge of the second trough <NUM> to the third trough <NUM> so that liquid flows from the second trough <NUM> over the overflow means <NUM> and the at least one deflector <NUM> into the third trough <NUM>, if the liquid level in the second trough <NUM> reaches the overflow means <NUM>.

Claim 1:
A liquid distributor (<NUM>) for a separation device (<NUM>), such as for a mass transfer column (<NUM>) in particular for a packing column for absorption, stripping, scrubbing or distillation, or for reactor, such as for distributing liquid above a catalyst bed of a reactor, wherein the liquid distributor (<NUM>) comprises at least one pre-distributor member (<NUM>) and a plurality of distributor members (<NUM>), wherein the at least one pre-distributor member (<NUM>) is positioned above the plurality of distributor members (<NUM>), wherein the at least one pre-distributor member (<NUM>) comprises at least two troughs (<NUM>, <NUM>, <NUM>), which each comprise a plurality of discharge openings (<NUM>), wherein each two of the at least two troughs (<NUM>, <NUM>, <NUM>) are connected with each other, wherein a first of the at least two troughs (<NUM>) has an overflow means (<NUM>) and at least one deflector (<NUM>) attached to the overflow means (<NUM>) or the side wall (<NUM>) of the first of the at least two troughs (<NUM>), wherein a second of the at least two troughs (<NUM>) has an upper edge, wherein at least one deflector (<NUM>) attached to the overflow means (<NUM>) of the first trough (<NUM>) extends from above the upper edge (<NUM>, <NUM>') of the second trough (<NUM>) to the second trough (<NUM>) so that liquid flows from the first trough (<NUM>) over the overflow means (<NUM>) or the side wall (<NUM>) and the at least one deflector (<NUM>) into the second trough (<NUM>), if the liquid level in the first trough (<NUM>) reaches the overflow means (<NUM>), wherein the distributor members (<NUM>) comprise a first group of distributor members (<NUM>) being arranged at least substantially in parallel to each other, which have the form of a hollow box having two side walls (<NUM>), two front walls and a bottom wall being connected with each other, wherein the bottom wall(s) and/or one of the side walls (<NUM>) has a plurality of discharge openings (<NUM>), wherein the top surface being opposite to the bottom wall is open and arranged so that liquid flowing through the plurality of discharge openings (<NUM>) of the at least two troughs (<NUM>, <NUM>, <NUM>) of the pre-distributor member (<NUM>) flows through the top surface into the distributor members (<NUM>) of the first group.