MXPA00001050A - Liquid distributor - Google Patents

Abstract

Significant savings of space inside a mass transfer tower can be obtained by use of a liquid distributor system with efficient uniform distribution from conduits such as troughs, pipes or deck distributors by means of flow spreader devices located predominantly below the conduit enabling closer spacing of liquid distribution points within the tower.

Description

PE LIQUID MBUIDOR BACKGROUND OF THE INVENTION This invention relates to internal structures, which are often referred to as "liquid dispensers", which are used in containers used in chemical plants and petroleum refineries for mass transfer and heat transfer applications such as distillation, fractionation, absorption , purification, contact, separation and damping. In said towers, the liquid is typically caused to flow down the tower to contact vapors that flow upstream to the tower. This contact tower can often have a plurality of segments, each one can comprise a distributor and packaging system, located sequentially in the same tower. It is often useful that the liquid flow in these segments is in the form of a thin film to maximize the degree and time of contact with the liquid. This can be achieved, for example, provided that the segments comprise random or structured packing elements in which the liquid streams leaving the distributor pass in the form of a thin film. Other methods for causing contact are known in the art. All these methods result in the liquid reaching the lower part of the tower segment containing said contact structures where it needs to be adjusted. Typically this is done through a series of collector devices that subsequently channel the liquid to the distributor conduits where it will pass back down to the next lower segment of the mass transfer tower. Similar distribution structures are located at the top of the towers at the point where liquid is introduced. In each case it is important that the liquid is distributed in the same way across the cross section of the tower to maximize the vapor / liquid contact potential that was created by the packing elements and to avoid unequal treatment of liquid and / or steam that passes through the device. Up to this point the distribution structures generally comprise distributor conduits, such as channels, feed-derived conduits, having openings in the walls through which a liquid flow can be directed to the upper levels of the package. Obviously it will be possible to multiply the number of openings in the walls of the derived channels to improve the development of a complete and expeditious humidification of the packing elements in a totally uniform manner. However, this would mean that the openings would need to be relatively small to ensure that each one receives an equal amount of liquid for distribution. Unfortunately, small holes are more prone to clogging up by solid impurities in the liquid flow and this results in an uneven flow which has to be avoided.

It is known that jj has to attack this problem by using relatively fewer larger holes and using devices to expand the flow from each hole so that it reaches the package as a plurality of drops. This is done by contacting the flow of liquid flowing horizontally from each opening with a vertical surface that expands the flow and terminates at a plurality of edges or points of runoff that contact the upper surfaces of the package. Suitable devices are described, for example, in the patents of E.U.A. 4,264,538; 4,816,191; and 4,855,089. These devices typically place a plate spreader opposite to the opening in the conduit wall so that the liquid that emerges collides with the plate and expands in a relatively thin flow that subsequently passes to the edges or runoff projections. This method can have disadvantages since the location of the plate necessarily limits the proximity of the adjacent conduits. further a partially blocked opening can reduce the flow to the point that liquid flow can not reach the plate. Also, if the flow is particularly strong, the position of the plate has to be adjusted to avoid spills or protections provided to ensure that the flow is channeled in the desired direction. In EP 0 501 615 A2 the liquid flowing from the openings in the side of a channel is channeled down a tube to a square, horizontal, spreader plate joined by vertical walls having * -SHßfiS-ií ** '* 5 * «- > discharge women in the corners. This divides the orifice flow from the channel into four smaller flows. In another device sold commercially by Hydronyl Ltd in the United Kingdom in the early 1970s, a liquid flow was distributed through closed ducts with a plurality of openings at opposite ends of a horizontal diameter or set of cords at a depth appropriate The liquid in the duct came out through the holes and is in contact with a vertical sheet metal spreader plate with a lower portion that led to the liquid film formed on the plate to a vertical perforated plate directly below the pipe so that liquid ran down on both sides of the perforated plate. Subsequently, in a preferred form, the vertical perforated plate was placed in contact with a similar vertical perforated plate placed at right angles to the first. This served to expand a portion of liquid at right angles to the rest of the flow and thereby improve the uniformity of distribution through the packing to which the descending circulation liquid was ultimately fed. This arrangement worked well but was subjected to many of the problems discussed above. In another prior art system the conduit is in the form of a platform provided with vertical pipes through which the gas can flow upwardly and a plurality of holes through which the downflow liquid can pass. This eliminates the problem of space but supplies the liquid in streams instead of starting from points of * runoff that are more important to promote uniform flow through the system. The present invention provides a novel and useful alternative to said devices. It has the advantage of allowing the use of relatively large holes that can minimize blockage while at the same time allowing a very broad and similar distribution of flow under a wide range of flow conditions.

GENERAL DESCRIPTION OF THE INVENTION The present invention provides a liquid dispensing system comprising a liquid distribution conduit having a plurality of openings for liquid distribution and, directly attached to the conduit, a conductive tube adapted to receive a liquid flow that comes out of the conduit through of the opening and leads it to a spreader plate, located at least partially below the level of the duct, which is inclined at an angle with respect to the horizontal which is 75 ° or less. The spreader plate is preferably at an angle of about 70 ° to 10 °, and most preferably 60 ° to 40 °, with respect to the horizontal. The degree of inclination with respect to Horizontal flow is largely determined by the flow velocity and therefore the degree to which it can expand before reaching the runoff points. Clearly, maximum expansion is desirable, and this often means a lower angle of inclination with respect to the horizontal within the anterior range. The liquid dispensing device forming part of this invention is described as a "conduit" and it is to be understood that this term includes any means for supplying a flow of liquid to a series of openings in the body of the conduit. This can have the shape of an open channel or closed pipe of any desired cross section, provided that it fulfills the function of distributing the liquid that flows in it, through the openings mentioned above. The conduit can also take the form of a platform distributor where a liquid flows through the platform and exits through the openings in reality on the floor of the platform. In this case the "conductor tube" is provided by the passage through the thickness of the platform by itself. In some cases it is convenient, provided that the surface of the spreader plate is textured, that the flow is reduced and it helps in the expansion. A plate extending the length of conduit can be used to handle the liquid leaving all conductive tubes connected to a conduit. Alternatively, but often less desirable, each conductive tube may have its own individual spreader plate. Where said individual spreader plates are provided each plate preferably has a fan shape to accommodate the expansion of the liquid flowing over it. Where the liquid flow rate is relatively low, ie 0.12 m3 per minute per m2, and particularly below 0.08 m3 per minute per m2, it is preferred that the spreader plate terminate at an edge where it prefers that the edge be replaced by a number of drip points that supply the liquid in a controlled manner to the packing 5 located below. A spreader plate that ends in a vertical extension element having a runoff edge or runoff points at the lower end is often preferred. This vertical extension element may also be perforated to allow liquid to pass through and through its surface also to pass through the thickness of the plate. The pour points may be provided on said perforated plate provided that the bottom edge passes through a multiplicity of said perforations. The runoff points may also be provided by projecting extensions from the lower edge of the element. This provision has the The potential advantage of expanding the liquid in a band thicker than the width of the plate by itself by deforming the projections outside the plane of the plate. However, the structures mentioned above are less effective while the flow velocity exceeds 0.12 m3 per minute per m2, and in such cases it is preferred that the spreader plate feed the liquid in a manifold channel having a plurality of liquid distribution means such as holes, slots, landfills, slits or other openings. The collecting channel preferably comprises opposite containment walls joined by a lower element and the liquid distribution means are preferably provided along the lower portion of at least one of the walls. This has the effect of ensuring a uniform flow rate through all media in the collector channel even when the total capacity of the conductor tube / spreader plate arrangement is exceeded for efficient operation. The collector channel may be completely separated from the spreader plate and this may be convenient if the collector channel is installed as a retroactive means to handle increased capacity requirements. However, when the liquid distributor system is designed from the beginning for high capacity systems, it is convenient to provide it in such a way that the vertical extension of the spreader plate forms one of the walls of the collecting channel. The collector channel is conveniently mounted directly below the conduit. This can be done by providing an extension of a wall of the collecting channel that is attached directly to the conduit along at least a portion of its length. The spreader plate is preferably provided with a weir at an intermediate point between the point at which the liquid flow makes contact with the plate and the vertical section, (when provided, or otherwise the lower end of the plate), and at right angles to the direct line formed by a continuation of the line of the conductive tube through the spreader plate. The function of the landfill is to interrupt the flow through the spreader plate and improve the expansion effect. The height of the spillway can be constant through the spreader plate but it is often convenient to provide it in such a way that it is higher along the lifting cable of the spreader plate inclined and the smaller at its ends. Alternatively and often it is preferred, that the landfill can be grooved so that the spaced apart portions of its length have reduced height to allow more liquid on its landfill at that point. The weir can extend through the full width of the spreader plate but generally ends a short distance from the edge of the spreader plate on both sides. The conductive tube may have a conventional shape where the side of the conduit provides a portion of the wall of the pipe and a suitably shaped element attached to the side of the channel provides a pipe of uniform cross section from the opening in the wall of the conduit to the point of discharge on the spreader plate. Thus, this cross section can be for example square, rectangular or basically circular with a portion of the flattened circumference. However, it can also have a non-typical cross section that defines two or more channels within the tube. These channels may, but need not, be completely separate but should preferably be sufficiently different to ensure that the volume of the liquid supplied from the end of the tube in the spreader plate is not uniform across the width of the tube. Said tube may have, for example, a more or less "B" shaped cross section. This has the property of initiating expansion by forming at least a partially partially divided flow actually inside the conductive tube. In use, it is often convenient to have the lower end of the spreader plate or any vertical extension element attached thereto be attached to the top of the package to avoid relative movement in response to differences and pressure variations. The anchoring device is commonly called a "grab bar" and can take any functional form that is desired.

DESCRIPTION OF THE DRAWINGS Figure 1 shows a diagrammatic cross section of a channel system according to the invention. Figures 2A and 2B show two alternative configurations of the conductive tube in cross section. Figure 3 shows a side view of a channel system according to the invention with a channel tube as shown in Figure 2B. Figure 4 shows a perspective view, which is partly sectioned in cross section, of an alternative configuration including a connector channel.

Figure 5 is a diagrammatic cross section showing a variation of the embodiment shown in Figure 4 where the vertical extension of the spreader plate provides a wall of the collecting channel.

DESCRIPTION OF THE PREFERRED MODALITIES The invention is now described with reference in particular to the drawings which are intended to illustrate the invention but do not necessarily imply any limitation on the scope thereof. In Figure 1 a duct channel with a rectangular cross section is provided with two outlet openings 2, and 3. The highest opening, 2, is only used in overflow situations or if the lower openings become clogged. The lower opening is the main vehicle through which the liquid is distributed in the channel. The openings shown are circular but in fact any suitable configuration can be adopted. Drop-shaped openings are often preferred since they are less prone to blockage. The channel will typically have many holes but only two are shown in this figure for simplicity. In use the liquid that leaves the channel through the holes and passes inside the conductive tube, 4, from which it is discharged into an inclined spreader plate, 5, where it expands while flowing down the plate until it reaches a landfill , 6, which also improves the expansion. The descending circulating liquid is subsequently contacted with a vertical extension element 7, which preferably is textured or even has openings. The extension element is fixed to the packing structures, 8, by means of a clamping bar, 9. The lower end of the extension element, 7, can be provided with a plurality of draining points whereby the liquid that Circulating in a descending manner can be distributed to the package. Figure 2A shows the design of the conductive tube that was used in Figure 1 in cross section. As can be seen, the tube 4 is formed by an arcuate element that is attached to the side of the channel, 1, over the opening, 2. Figure 2B shows the design of the conductive tube that was used in figure 3. This tube it has the "B" shaped cross section that allows the liquid to flow to be fixed in two streams as it leaves the opening in the channel. In Figure 3 the conductor tube, 4, has a "B" shaped cross section. The liquid that passes through the conductive tube in contact with the inclined spreader plate, 5, expands and makes contact with a slotted weir, 6. In other aspects the structure is very similar to that illustrated in Figure 1. In Figure 4 illustrates a design that is intended to be used at higher flow rates. The duct, the openings, the conductive tube and the spreader plate are as shown in the previous figures, but in this case the spreader plate is fed into a collecting duct 10, provided with holes, 11, along the lower portion from at least one of the walls. As indicated above, these holes can be replaced or replaced with slots, landfills and / or slits. The collecting channel is joined to the conduit by a support extension, 12, on one of the walls of the channel. Figure 5 shows a diagrammatic sketch of a variation in the embodiment shown in Figure 4 in which the spreader plate has a vertical extension, 13, which provides one of the walls of the collector channel. Many variations can be made in the structures that were described above without departing from the essential structure of the present invention. For example it is possible to replace the conductive tubes shown in the drawings with a separate tube attached over the opening in the side of the conduit. It is preferred that the diameter of the tube be substantially larger than the opening to ensure that the flow remains free rather than compressed. Another variation in the cross-sectional shape of the conduit is possible. In the drawings the cross section is rectangular but there is no requirement that makes other cross sections, such as round or V-shaped, inadequate. They can also be opened or closed.

Claims (10)

- ÍNVENTION OF THENVENTION CLAIMS

1. - A liquid distributor system comprising a conduit having a plurality of liquid distribution openings and, directly attached to a wall of the conduit, a plurality of conduit tubes each adapted to receive a flow of liquid exiting the conduit through of vertically aligned openings and discharges it directly into an angular spreader plate located at least partially below the conduit and inclined at an angle below with respect to the horizontal that is not greater than 75 ° so that the liquid leaving a conduit expands in a relatively thin flow.

2. The system according to claim 1, further characterized in that the spreader plate is inclined at an angle of 10 to 70 ° with respect to the horizontal.

3. The system according to claim 1, further characterized in that the spreader plate is provided with a spillway.

4. The system according to claim 1, further characterized in that the spreader plate is provided with a vertical extension element extending downward. ! &? tf $ &i!? lte! Qili ?? M *? tÍbl S »? Bßí?« a * <

5. The system according to claim 4, further characterized in that the vertical extension of the spreader plate ends in a plurality of runoff projections.

6. The system according to claim 1, further characterized in that the spreader plate terminates in a plurality of runoff projections.

7. The system according to claim 1, further characterized in that the spreader plate ends at a lower edge located above a collecting channel comprising containment walls provided with a 10 plurality of distribution holes in at least one of the containment walls.

8. The system according to claim 4, further characterized in that the vertical extension of the spreader plate provides a retaining wall of a collecting channel provided with a plurality of distribution means in at least one retaining wall of the channel manifold.

9. The system according to claim 1, further characterized in that the conductor tube has a cross section that defines at least two interior channels within the tube.

10. The system according to claim 1, further characterized in that the conductor tube is attached to the side of the conduit.