Patent Publication Number: US-2010126621-A1

Title: High Velocity Low Impact Liquid Feed Distributor

Description:
BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     This invention concerns liquid feed distributors that are capable of distributing a high velocity feed with a corresponding low pressure drop with little to no fouling. 
     (2) Description of the Prior Art 
     Introducing a liquid feed uniformly into a liquid filled vessel such as a contactor can be difficult. Often, distributors with complex distribution piping are used to uniformly distribute a liquid feed across a cross section of a vessel. Currently available distributors generally include primary and secondary distribution arms or manifolds. One or both of the primary and secondary distribution arms will typically include a multitude of small holes through which a liquid feed flows into a vessel. As a result of the number of distribution arms and the multitude of small holes, the pressure drop across the distributor—as the liquid feed flows through the distributor into the vessel—is very low. This correlates to a low velocity for the liquid flowing through the distributor distribution arms and small holes. 
     Low liquid velocities in the distribution arms can lead to distributor fouling in certain applications. For example, where solids are suspended in or formed in the liquid feed, the solids can foul the distribution arms and/or small holes because the liquid feed velocity is not great enough to prevent the solid materials from blocking or plugging the arms and holes. This in turn can result in non-uniform liquid distribution. There is a need, therefore, for liquid distributors that distribute liquids at higher velocities and/or that do not include structures or features that are prone to fouling and plugging. Moreover, there is a need for new distributors that introduce one or more immiscible liquids into a vessel. 
     SUMMARY OF THE INVENTION 
     The present invention solves one or more of the problems with prior art liquid distributors by providing a device that allows liquids to be introduced into a vessel at high velocities. The devices of this invention include features that quickly distribute the introduced high velocity liquid throughout a vessel while simultaneously reducing the velocity of introduced liquid. 
     One aspect of this invention are liquid distribution devices comprising: a liquid distributor including an inlet pipe, and a piping manifold connected to a first end of the inlet pipe wherein the piping manifold includes a plurality of liquid distribution pipes each liquid distribution pipe including an inlet connected to the piping manifold and an outlet; and an impact portion comprising a plurality of pans, each pan having a top surface wherein at least one pan top surface is oriented essentially perpendicular to the direction of liquid exiting the outlet of at least one of the plurality of liquid distribution pipes. 
     Another aspect of this invention are liquid distribution devices comprising: a liquid distributor including an inlet pipe and a piping manifold connected to the inlet pipe wherein the piping manifold includes a plurality of liquid distribution pipes each liquid distribution pipe including an inlet connected to the piping manifold and a downwardly oriented outlet wherein outlets distribution pipe are essentially co-planar; and an impact portion that includes a plurality of pans having essentially co-planar and circular top surfaces wherein each of the plurality of pans is associated with a different liquid distribution pipe outlet, wherein each pan top surface is essentially perpendicular to the direction of liquid exiting each liquid distribution pipe outlet. 
     Yet another aspect of this invention are methods for distributing liquid in a vessel comprising; installing in a vessel a liquid distribution device including an inlet pipe, and a piping manifold connected to a first end of the inlet pipe wherein the piping manifold includes a plurality of liquid distribution pipes each liquid distribution pipe including an inlet connected to the piping manifold and an outlet, and an impact portion comprising a plurality of pans each pan having a top surface wherein at least one pan top surface is essentially perpendicular to the direction of liquid exiting the outlet of one or more of the plurality of liquid distribution pipes; directing liquid through the inlet pipe into the piping manifold in an amount sufficient to product a liquid velocity at the outlet of each of the plurality of liquid distribution pipes ranging from about 1.2 to about 7.5 M/sec.; and directing the liquid flowing from the outlet of each of the plurality of liquid distribution pipes at the top surface of at least one pan such that at least a portion of the directed liquid flows is redirected radially away from the center of the pan and wherein the velocity of the liquid flowing radially away from the center of the pan and measured at the perimeter of the pan is no more than about 1.5 M/second. 
    
    
     
       DESCRIPTION OF THE FIGURES 
         FIG. 1  is side view of a liquid distributor embodiment of this invention including a liquid distributor ( 10 ) and an impact portion ( 30 ); 
         FIG. 2  is a bottom view looking up at impact portion ( 30 ) of a liquid distributor embodiment of this invention; 
         FIGS. 3A and 3B  are side and top views of one possible pan embodiment of this invention; and 
         FIG. 4  is a side view showing examples of relationships between distributors and pans associated with liquid distribution devices of this invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is directed to liquid distribution devices that are useful for quickly directing liquids moving at high initial velocities into liquid containing vessels and thereafter quickly reducing the velocity of the introduced liquid to uniformly distribute the introduced liquid in the vessel. Unlike liquid distributors of the prior art, the liquid distribution devices of this invention do not include small orifices. Therefore, the present invention solves at least some of the problems associated with distributing liquids at low velocity through a multitude of small orifices. The liquid distribution devices of this invention solve some of the prior art distribution problems because they include a plurality of liquid distribution pipes that direct liquids at high velocities towards opposing pans. When the high velocity liquid exiting the distribution pipe outlets impacts the pans, the liquid flow is redirected and further distributed causing a substantial reduction in the velocity of the liquid as it flows off of the pan(s). 
     The liquid distribution devices of this invention will now be described with reference to  FIGS. 1-4 . The liquid distribution devices of this invention comprise two primary elements. The first primary element is a liquid distributor  10  and the second primary element is a liquid impact portion  30 . Liquid distributor  10  and liquid impact portion  30  may be connected to each other to form a single liquid distribution device structure that is located in a vessel. Alternatively, liquid distributor  10  and impact portion  30  may be independently associated with a vessel in a manner that causes them to be oriented as described below. 
     Referring now to  FIG. 1 , liquid distributor  10  includes an inlet pipe  12  having a first end  14  that is associated with piping manifold  16 . The opposing second end of inlet pipe  12  (not shown) will be associated with a liquid feed source such as a pump that is associated with a liquid filled feed tank, with a liquid feed source, etc. . . . Piping manifold  16  includes a plurality of liquid distribution pipes  18 . Each liquid distribution pipe  18  includes an inlet  20  that is associated with piping manifold  16  and an open outlet  22 . 
     Liquid distribution pipes  18  and their corresponding outlets  22  may be associated with piping manifold  16  in any number and in any orientation that will efficiently distribute liquid in a vessel. The number of liquid distribution pipes  18  used will vary depending upon a variety of factors including but not limited to the liquid vessel cross-sectional area, the design liquid feed rate and the desired feed velocity exiting outlets  22 . 
     The piping manifold  16  and distribution pipes  18  will generally be associated with manifold  16  and have lengths and internal dimensions to ensure, as much as practical, that essentially the same volume liquid at essentially the same velocity exits the outlet  22  of each liquid distribution pipe  10 . Generally, the velocity of liquid exiting outlet  22  will range from about 1.2 to about 7.5 M/sec, more preferably from about 2.0 to about 6.0 M/sec. and most preferably from about 3.5 to about 5.0 M/sec. However, in some instances it might be beneficial to design distributor  10  such that pipes  18  distribute different volumes of liquids and/or deliver liquids at different velocities to different vessel locations. 
     The velocity of the liquid exiting outlets  22  of liquid distribution pipes  18  must be reduced in order to ensure uniform liquid feed distribution in the vessel. Impact portion  30  provides the liquid velocity reducing elements. An impact portion  30  of liquid distribution devices of this invention is shown in  FIG. 1 . Impact portion  30  includes a plurality of pans  32  where each pan includes a top surface  34  and a bottom surface  36 . The pan top surface  34  will preferably have an area that is large enough to reduce the velocity of liquid exiting outlet  22  that impinges upon pan  32 . In one embodiment the pan reduces the velocity of the liquid flowing laterally at edge  33  of pan  32  to about no more than 1.5 M/sec, preferably no more than about 0.6 M/sec. and most preferably no more than about 0.25 M/sec. Generally, each pan  32  will have cross sectional area that is from 4 to 200 times the cross sectional area of a corresponding liquid distribution pipe outlet or outlets  22 . For example, in a typical vessel, outlets  22  will have circular openings having a diameter of from about 2 cm to about 6 cm or more. The pans  32  will be circular with diameters of about 30 cm to about 50 cm. 
     Pan  32  may be any shape capable of reducing the velocity of liquid exiting outlet  22  to a desired rate including but not limited to shapes such as circular, square, a star, rectangle and amorphous shaped. It is preferred, however, that pan  32  is circular in shape. Moreover, it is preferred that outlet  22  of a liquid distribution pipe is orientated at pan top surface such that the liquid emerging from outlet  22  impacts pan top surface  34  at essentially the center  35  of pan top surface  34 . In most instances this will mean that outlets  22  will be oriented with respect to pans  32  such that the liquid flowing out of outlet  22  impacts pan top surface  34  perpendicularly. The combination of a pan circular shape and directing liquid emerging from outlet  22  at the center of the circular pan top surface  34  causes the liquid to change flow direction by most 90° and be distributed volume-wise essentially uniformly across the pan top surface  34 . The combination further facilitates the efficient drop in the liquid velocity of the liquid exiting outlet  22 . As liquid flows from outlet  22  impacts top surface  34  of pan  32 , the liquid flow is redirected so that it flows parallel to pan top  34 . Initially, the horizontal velocity is proportional to the radius of outlet  22 . As the liquid that flows across pan top surface  34 , the liquid horizontal velocity decreases. These distances that the liquid flows over the top of the pan to surface  34  will preferably be great enough so that the liquid velocity drops from about 1.2 to about 7.5 M/sec at outlet  22  to about from 0.25 to 1.5 M/sec. at the pan perimeter. Moreover, these dimensions will generally reduce the liquid velocity uniformly as the liquid passes across the pan top surface  34  meaning that the velocity of liquid at any point around edge  33  of pan  32  will be essentially equivalent and/or will fall below the liquid velocities at the pan perimeter recited above. 
     It is contemplated that a single pan  32  can be associated with more than one liquid distribution pipe outlet  22 . For example, two liquid distribution pipe outlets  22  can be associated with a single pan  32  having a top surface shaped like a figure-eight. In this embodiment, each outlet  22  would be centered over one of the circular portions of the figure-eight. It is preferred however that each liquid distribution pipe outlet  22  be associated with a corresponding pan  32 . This way, every outlet  22  can be located, as much as possible, over the center of the pan top surface  34  towards which it is directed and it minimizes interaction between liquid streams exiting different distribution outlets  22 . 
     When installed in a vessel as shown in  FIG. 1 , pans  32  will preferably be oriented such that each pan top surface  34  is perpendicular to the direction of the flow of liquid exiting each outlet  22  of liquid distribution pipes  18 . Since the liquid exits liquid distribution pipes  18  at high velocities, the liquid will impinge against pan top surface  34  at a high velocity which will change the direction of the liquid and cause it to flow laterally towards edge  33  of pans  32  in all lateral directions thereby distributing the liquid evenly throughout the vessel. 
     The distance H between an outlet  22  of a distribution pipe  18  and a top surface  34  of pan  32  may vary. H should be a distance that allows essentially all of the liquid passing through outlet  22  to impinge against pan top surface  34  and it also should be at a distance that, in conjunction with the pan dimensions, causes the liquid flowing off the pan perimeter to be at the desired liquid flow velocity and preferably from 0.25 to 1.5 M/sec. at the pan perimeter. For example H may range from about 5 cm to about 60 cm or more. 
     The distance H may be the same for all distribution pipes and pans in a liquid distribution device or some heights H may be the same and some different or all of the heights H may be different for different outlet/pan combinations. This aspect of the invention is shown in  FIG. 4  which includes a horizontal piping manifold  16  having a plurality of liquid distribution pipes  18 . In  FIG. 4 , the liquid distribution pipe outlets  22  are not all coplanar. However, in a preferred embodiment, the outlets  22  will be coplanar. Additionally, the top surface  34  of each pan  32  is also not coplanar in  FIG. 4 . However, in a preferred embodiment, the top surface of pans  32  will all be essentially coplanar with respect to one another. Finally, in  FIG. 4 , the distances H between outlet  22  and pans  32  vary. However when outlet  22  and pans  32  are both essentially coplanar, distance H will be essentially the same for all outlet/pan pairs. 
     Pan top surface  34  may include a particle and/or velocity reducing surface that promotes the reduction of the size of any particles in the vessel or in the liquid exiting liquid distribution pipe outlets  22 . However, any pan top surface features that might facilitate particle size reduction may also facilitate unwanted deposition of particles on the pan surface. Therefore, it is generally preferred that the pan top surface is smooth. 
     Pan top surface  34  may include ridges  41  that are notched or serrated so that they are useful for controlling the level of liquid on the pan  30 . A preferred ridge  41  is serrated as shown in  FIGS. 3A and 3B . In  FIGS. 3A-3B , the serrated ridges  41  are radial spaced apart serrations that originate at the center of pan top surface  34  and that radiate end at pan perimeter  33 . The distance between the peaks  37  and valleys  39  of serrations is not especially critical. However, useful serrations will generally have a distance between a peak  37  and a valley  39  of from about 1 cm to about 5 cm. 
     One example of a vessel cross section having a plurality of pans  30  is shown in  FIG. 2 . The cross section shown in  FIG. 2  includes a center pan  32 A and a plurality of peripheral pans  32 B. Peripheral pans  32 B may be oriented with respect with center pan  32 A in any manner that allows flowing from distributor pipe outlets to be evenly distributed in the vessel. In one embodiment, pans  32 B will be orientated in a spoke-type pattern with respect to center pan  32 A. In this embodiment, each peripheral pan  32 B is separated from its adjacent peripheral pan  32 B by an angle α where the angle α is generally the same for each pair of adjacent peripheral pans  32 B. It should be noted however, that the angle a need not be the same and may be different for one to all of the adjacent peripheral pans  32 B. 
     the term “essentially” is used herein to modify certain terms. As the term “essentially” takes into consideration that there may be some variance from the desired orientation, length, plan, center, etc. . . . due to, for example, device construction and installation factors. 
       FIG. 1  is an embodiment of a liquid distributor of this invention installed in a vessel  50 . Vessel  50  includes a wall  51  having an outside surface  54  and an inside surface  56 . Gusset plates  60  support pans  32  or in the alternative gusset plates  60  support horizontal beams  66  which in turn support pans  32 . Gusset plates  60  thereby secure impact portion  30  in place during vessel operation. In the embodiment shown in  FIG. 1 , vertical support beams  67  associated with pan support beams  66  retain one or more of liquid distribution pipes  18  or manifold  16  in place in vessel  50 . The methods for supporting and retaining liquid distributor  10  and liquid impact portion  30  in place in a vessel shown in  FIG. 1  are just examples of methods for securing vessel intervals in place. Any other methods known to one of ordinary skill in the art for securing distributors or other internals in place in a vessel during operation may be employed in this invention. 
       FIG. 1  shows an orientation of liquid distributor  10  with respect to liquid impact portion  30  whereby the liquid distribution pipe outlets are downwardly orientated and whereby pans  30  are orientated horizontally underneath outlets  22  of liquid distribution pipe  18 . Any other pan/outlet orientation that is useful in distributing liquid fed into a vessel may be used. For example, the liquid distribution pipe outlets  22  may be upwardly oriented towards horizontal pans  32 . Alternatively, the outlets  22  may be oriented at an angle with respect to vessel. The important feature of any orientation of liquid distributor  10  with respect to impact portion is that pans  32  should always be oriented such that pan surface  34  is essentially perpendicular to the flow of liquid exiting liquid distribution pipe outlets  22 .