Patent Application
20100126621
(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.
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.
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
Referring now to
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
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
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
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
One example of a vessel cross section having a plurality of pans 30 is shown in
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.
