JP4749490B2 - Apparatus and method for dispensing liquid - Google Patents

Description

  The present invention generally relates to a liquid dispensing device typically used in a mass transfer column and a method for dispensing liquid using the liquid dispensing device.

  Various types of exchange columns are known in the art in which gases and liquids are in contact with each other for the purpose of mass or heat transfer, fractionation or separation of the feedstock components and other apparatus operations. The countercurrent flow of vapor and liquid in such an exchange column is an established vapor-liquid contact method. The actual vapor-liquid interface requires the use of a distillation tray or packed bed in the column. Liquid is distributed above the tray or packed bed, while vapor is distributed below the tray or packed bed. Liquid that falls to the tray or drops down through the packed bed is exposed to the vapor rising upward due to vapor-liquid contact and interaction.

  The internal configuration of the column determines the vapor-liquid interface that occurs within the process tower and the efficiency of simultaneous mass and energy transfer. Effective and uniform distribution of vapors and liquids on opposite sides of a distillation tray or packed bed that forms a homogeneous mixing zone is also critical to effective operation. Non-uniform liquid distribution can result in poor contact and mass transfer between the rising vapor flow and the falling liquid flow. There are many designs today because efficiency translates immediately into operating costs and manufacturing quality. However, the efficiency of the column is limited by the efficiency of vapor and liquid distribution across the column. For example, if either vapor or liquid is not evenly distributed on a portion of the distillation tray or packed bed, that portion will not be used to its full potential, thus reducing operating efficiency and cost effectiveness. Will be reduced. For this reason, apart from the tray and the packed bed itself, the liquid distribution device is the most important device inside the tower. Poor tower performance may be due to liquid distribution problems such as clogging or uneven distribution.

  When using a packed bed, efficiency can be lost through small, inhomogeneous areas of interaction between vapor and liquid. Many high-efficiency filling designs require a vapor-liquid countercurrent flow through the passage defined by the opposing undulations of the sheet. If the initial distribution of liquid or gas is unable to enter a particular corrugated pattern, the liquid and vapor are energized until they enter the unfilled filling area and interact through this filling area. Valuable surface area in the device is lost. As a result, the efficiency is poor. Better distribution of the liquid across the packed area will alleviate this problem, and in order to better distribute the liquid across the packed area, the uniform distribution of liquid in the split box fed to the packed bed distributor. It is desirable to improve distribution. If the liquid entering the column is more evenly distributed across each part of the split box, each part of the split box can deliver the liquid feed uniformly by the packed bed distributor. The novel liquid distributor of the present invention can function as a split box that supplies an accurate amount of liquid to the packed bed distributor in a uniform distribution.

  Many prior art devices, such as spray orifices, pipes, perforated plates, open troughs and nozzles, generally collect some vapor and some liquid in most trays or packed bed distribution devices. Although effective for dispensing to any part, it is usually not possible to achieve uniform distribution without the use of more sophisticated dispensing devices. For example, as a result of simply spraying the liquid onto the top of the tray, the liquid flow is often high in certain parts of the tray and low in other parts. The orifice dispensing device as a whole is prone to clogging and non-uniform irrigation within the tower. Similarly, irregularities in the surface of the dispensing pan that occur during manufacturing can increase flow resistance in some holes or induce liquid flow along the bottom of the pan, which is clearly It is disadvantageous. Overall, any flow irregularities that cause flow to converge in one region while reducing flow in other regions are detrimental to operating efficiency.

  It would be desirable to provide an assembly that distributes liquid evenly and evenly onto a tray. Examples of conventional designs include US Pat. No. 6,722,639 and US Pat. No. 4,729,857. U.S. Pat. No. 4,729,857 discloses a liquid flow distribution apparatus having a plurality of troughs with a downwardly tapered body portion having holes formed to eject liquid outward. Teach. A baffle plate is disposed on the outside of the body portion tapered below the trough to receive the liquid discharge and evenly distribute the liquid flow downward. US Pat. No. 6,722,639 teaches a liquid dispensing apparatus that includes a plurality of elongated troughs that are spaced apart and extend across a column. A plurality of liquid drain holes are disposed in one or more preselected planes that are preferably located in the trough sidewalls and spaced apart above the trough floor. The baffle plate is spaced apart outwardly from the trough sidewalls and includes an upper portion arranged to receive liquid exiting the trough through the drain holes. The lower part of the baffle plate forms a narrow outlet in the plane below the trough, and delivers liquid from the baffle plate to the mass transfer bed located below. The baffle plate is vertically adjustable and is supported on the top surface of the mass transfer bed, and the discharged liquid is sent directly to the mass transfer bed, so that the falling liquid passes through the mass transfer bed upward. The purpose is to reduce the chance of being taken into the steam flow.

  The present invention provides a novel liquid dispensing assembly that is more efficient than that of the art, especially in situations where the velocity of the liquid in the flow tube is high. In this highly efficient dispensing device, a uniform flow of liquid is maintained through the flow equalizing device. The apparatus holds a trough having a patterned opening, a perforated v-shaped plate disposed within the trough, and a flow tube disposed above the trough. One preferred embodiment further includes a divider disposed within the perforated v-shaped plate. The apparatus can be used to evenly distribute liquid to the distillation tray. In some applications, the device or multiple device sets can be used as a split box to evenly distribute liquid to the packed bed dispensing device.

  The flow tube typically delivers the multiphase liquid to an open trough having a discharge opening arranged in a specific pattern. In some embodiments, multiple flow tubes can deliver liquid to an open trough network. Troughs are commonly used in mass transfer columns to receive liquid from the upper area and redistribute it uniformly to the lower tray. However, if the flow tube discharges directly into the open trough, the liquid will be discharged from the trough opening at a non-uniform flow rate. Those openings that are directly aligned with the outlet from the flow tube experience a higher flow of liquid, and openings that are not aligned with the outlet of the flow pipe experience a lower flow of liquid. With the v-shaped plate of the present invention housed in the trough, the flow rate of liquid discharged from the flow tube is split and changed so that the liquid flowing into the trough through the holes in the v-shaped plate is more uniform. It becomes. The uniformity of the liquid flow rate is further improved in embodiments where the perforated v-shaped plate is provided with a divider. In one alternative embodiment, multiple troughs act as a split box that uniformly redistributes to a liquid-filled bed distributor.

  In one embodiment, the present invention relates to a liquid distribution apparatus for use in a mass transfer column having one or more distillation trays disposed in an open interior region within the column. The liquid distributor serves to distribute the descending liquid flow evenly across the tray and interact with the rising vapor stream. The liquid distributor has at least one optional feed tube that delivers a flow of liquid to at least one lower elongated trough that extends across the column. The trough has spaced apart first and second sidewalls interconnected by a floor. A plurality of liquid discharge holes are disposed at least on the floor. The liquid dispensing device further includes a perforated v-shaped plate disposed within the trough so that the liquid from the supply tube passes through the perforated v-shaped plate before encountering the trough floor. The plate is preferably in the form of a “v” shape, but it is conceivable to have a number of v shapes such as a W shape. As the liquid passes through the perforated v-plate, the flow is divided into lower velocity smaller flows, providing a more uniform overall flow rate flowing through the trough. The liquid is then pumped directly from the trough outlet to the top surface of the tray at a substantially uniform flow rate across the trough.

  In one embodiment, the liquid dispensing device further holds solid vertical dividers arranged perpendicular to the length of the plates, the dividers straddling the width of the plates and It extends within the volume defined by the v-shaped plate. The divider defines regions along the length of the v-plate and provides at least a partial barrier to the horizontal flow of liquid between the regions. The divider selectively allows regional overflow passages that provide a path for liquid to flow between regions when the liquid level in the v-plate reaches a particular level. In yet another embodiment, the v-shaped plate is supported in the trough by a support support.

  In another embodiment of the present invention, the liquid distribution device is in a mass transfer column having a packed bed distribution device and one or more packed beds disposed in an open interior region within the column. Used. The liquid distributor functions as a split box that distributes uniformly across the bed distributor filled with the descending liquid flow. In this embodiment, troughs present in a plurality of troughs extend across the column in a parallel relationship and the troughs allow steam to flow upward through the spacing between adjacent troughs. So that they are separated. The liquid from the trough is evenly distributed to a packed bed distributor located in the column below the trough.

  In the accompanying drawings, which form a part of this specification and are to be read together with this specification, like reference numerals are used in various figures to indicate like parts.

FIG. 3 is a top view showing a trough having an opening pattern on a trough floor. FIG. 6 is a top view showing one embodiment of a liquid distributor assembly including a flow tube, a v-plate, a divider, and a trough. FIG. 6 is a side view of a liquid distributor assembly in a column positioned above a distillation tray or packed bed distributor. FIG. 5 is an end view of a bracket that supports a flow tube of a liquid distributor assembly. 1 is an end view of a liquid distributor assembly including a flow tube, a v-plate, a divider, and a trough. FIG. FIG. 6 is an enlarged partial perspective view of a perforated v-shaped plate of a liquid distributor assembly. FIG. 6 is an end view of the divider of the liquid distributor assembly. FIG. 5 is an enlarged partial perspective view showing a perforated v-shaped plate of a fluid divider assembly, wherein the v-shaped plate has a number of v-shaped and is w-shaped. FIG. 6 is a cross-sectional end view showing one embodiment of a trough and a v-shaped plate. It is a section end view showing another embodiment of a trough and a v-shaped board. FIG. 5 is a cross-sectional side view showing a liquid distributor assembly. FIG. 6 is a cross-sectional end view showing a liquid distributor assembly.

  The mass transfer or heat exchange column includes an upright cylindrical shell that defines an open interior region in which one or more liquid distributors of the present invention and one or more distillation trays are located. The liquid distributor is used to more evenly distribute one or more descending liquid streams across the horizontal cross section of the distillation tray, while the distillation tray is used to distribute the descending liquid stream and one or more ascents. Promote contact between the steam flow. Some columns employ one or more mass transfer beds instead of trays. The mass transfer bed is equipped with various known types of mass transfer devices, not limited to what is conventionally known as a lattice or random packing as a structure. The liquid is distributed to the floor using a packed bed distributor, which is usually supplied from a packed bed split box. The novel liquid dispensing device can be used in place of a more conventional type of packed bed separation box and can be evenly distributed by the liquid filled bed dispensing device.

  The column is of the type used to process liquid and vapor streams, including obtaining fractionated products. The column can be cylindrical or other shapes including polygons. The column is of any suitable diameter and height and preferably is inert to the fluids and conditions present in the column, i.e. otherwise adaptable, suitably rigid. Manufactured with materials.

  The liquid flow is directed to the column through a supply tube positioned at an appropriate location along the height of the column. The supply tube normally carries only liquid, but can also carry vapor with or in lieu of liquid. The column includes at least one overhead tube that removes vapor products or by-products and a bottom flow discharge tube that removes liquid products or by-products from the column. Other column components may also be present, such as reflux flow tubes, reboilers, condensers, steam horns and the like.

  Referring now to FIGS. 1, 2, 3, and 5, the liquid dispensing device 2 preferably includes an elongated trough 4 that receives liquid from a liquid stream conducted in the flow tube 6. The flow tube 6 has a series of outlet holes 24 for discharging liquid. The flow tube 6 is placed above the trough 4 to allow the liquid to be introduced by gravity. The flow tube 6 typically has a diameter in the range of 5 to 91 cm (2 to 36 inches), although larger diameters are also suitable. The total area of the outlet holes 24 is typically 50% or less of the cross-sectional area of the flow tube 6. The flow tube 6 can be of various shapes, such as straight, “T” shaped, and “H” shaped, or can comprise a main exhaust manifold with side branches. it can.

  The trough 4 preferably extends horizontally in the first direction and has a length corresponding to the diameter of the column or at least a substantial part thereof. The trough 4 has opposed side walls 8, 10 connected by a floor 12 and end walls 14, 16. A plurality of discharge holes 18 are provided in the floor 12 for delivering liquid to at least one distillation tray. In the column 3, the trough is usually arranged through the center of the column 3 extending in the longitudinal direction. The trough preferably extends completely or substantially across the column and is supported at its ends by means such as an upper ring welded to the inner surface of the shell. Other support means can be used, such as by using an intermediate beam located above the trough, attaching the trough to the flow tube, and using the support grid of the distributor. . The trough dimensions and specific configurations can be varied to suit the specific liquid and vapor load requirements of the intended application.

  The trough 4 includes a plurality of spaced apart liquid discharge holes 18 disposed in the floor 12. The discharge holes 18 are preferably arranged in a preselected pattern that is specially formed to fit a particular column and distillation tray. The pattern of the discharge holes 18 extends along the length of the trough 4. The discharge holes 18 are typically circular and have the same dimensions, but may have other shapes and different dimensions. The liquid flows through the discharge holes 18 and likewise falls to the distillation tray or packed bed distributor 35 contained in the column 3 (details of the distillation tray or packed distributor are shown). Absent).

  The trough 4 of the liquid distributor 2 contains a perforated v-shaped plate 20 that extends along the length of the trough. The V-shaped plate 20 allows the vapor to be exhausted while reducing or eliminating turbulence or moments in the liquid. Similar to the discharge hole 18, the hole portion 22 of the v-shaped plate 20 is typically circular and has the same dimensions, but may have other shapes and different dimensions. The holes provide a dividing function, but at the same time are dimensioned enough to prevent the liquid from being unduly stopped and accumulated in the v-shaped plate. The holes 22 can be arranged in any pattern, but are preferably separated and separated in a uniform pattern extending above the complete surface of the v-shaped plate 20. In one embodiment of the present invention, the holes 22 provide 40% of the v-plate surface area as an open area for liquid to flow through the v-plate 20. The V-shaped plate 20 extends into the volume formed by the trough 4 but does not extend so much as to contact the floor 12 of the trough 4. The base of the v-shaped plate 20 is preferably adjacent to the liquid head in the trough 4 but not above the head. In one embodiment, the base of the v-plate, ie, the lower portion of the v-plate, is 15.24 cm (6 inches) from the trough floor. Of course, this dimension can be varied depending on the design.

  In one embodiment, the v-shaped plate straddles the width of the trough 4 extending from the side wall 8 to the side wall 10. See FIG. In another embodiment, the v-shaped plate is supported in the trough 4 but does not extend from the side wall 8 to the side wall 10. Instead, the support 30 is used to support the v-shaped plate within the volume of the trough 4. FIGS. 9a and 9b show a comparative enlarged view of two different embodiments of the present invention. In FIG. 9a, a v-shaped plate 20 extending from the side wall 8 to the side wall 10 is shown. On the other hand, FIG. 9 b shows a v-shaped plate 20 supported by a support 30 that extends from the side wall 8 to the side wall 10. Each of the designs allows proper exhaust through the trough. In FIG. 9 a, the holes 22 in the v-shaped plate 20 adjacent to the tops of the side walls 8, 10 allow steam to flow through the v-shaped plate indicated by arrow 32. A hole 22 in the v-shaped plate 20 adjacent to the base of the v-shaped plate 22 allows liquid to flow through the v-shaped plate as indicated by arrow 34. In FIG. 9 b, the brace 30 allows the steam to be exhausted through the trough indicated by arrow 32. The holes 22 in the v-shaped plate 20 allow liquid to flow through the v-shaped plate indicated by the arrow 34.

  Although not necessarily required, maximum efficiency is achieved when the v-shaped base of the v-plate is positioned in alignment with the outlet hole 24 of the flow tube 6. It is within the scope of the present invention that the perforated v-shaped plate retains a v-shaped majority such as a w-shape. See FIG. A w-shape is beneficial in situations where the flow tube 6 has two rows of outlet holes. The plate has a first v-shaped base forming a w-shape aligned with a first row of outlet holes in the flow tube, and a second v-shaped base forming a w-shape is a second of the flow tube. Will be aligned with the outlet holes in the rows of

  As the fluid flow exits the flow tube through the outlet hole, the flow flows primarily vertically downward within the local region below the outlet hole. If the flow continues uninterrupted to the trough floor, the amount of fluid through the different trough drain holes and the velocity of the fluid will vary depending on the position of the drain holes. For example, a discharge hole that is aligned perpendicular to the outlet hole of the flow tube will provide a higher rate and more liquid than a discharge hole that is not aligned with the outlet hole of the flow tube. In addition, significant turbulence is generated by the liquid exiting the flow tube and striking the trough floor. This turbulence further breaks up the liquid passing through the trough discharge holes. The present invention employs a v-shaped plate to interrupt the flow of liquid from the outlet hole of the fluid pipe in front of the trough floor. The v-shaped plate serves to divide each of the fluid streams exiting the flow tube into a number of smaller streams that spread evenly above the trough floor. Furthermore, the action of splitting a large flow of fluid from the fluid tube into many smaller flows results in a decrease in liquid velocity and equalization of the velocity of many small flows descending to the trough bed. Splitting a large flow of fluid from a fluid tube into many smaller flows also serves to significantly reduce liquid turbulence in the trough bed. The overall result is that the liquid is distributed more uniformly and in a less turbulent state to the trough bed, which means that the liquid can be evacuated to the floor drain holes compared to other liquid distributor designs. Will be allowed to distribute more evenly through.

  Depending on the configuration and speed of the liquid in the flow tube, the liquid flow discharged from the outlet hole of the flow tube will contain a horizontal component and an expected vertical component. Thus, the flow will be sprayed outward at an angle away from a vertical plane aligned with the exit hole from the flow tube. When the horizontal component of the liquid flow from the outlet hole of the flow tube remains unchecked, the liquid flowing through the different holes in the v-plate will have a different direction flow moment and will cause an imbalance in the liquid head. Will form. The small flow created by the v-shaped plate will not be able to distribute the liquid uniformly and will be heavily concentrated in the trough part depending on the horizontal component of the different flow moments.

  To address this problem, one embodiment of the present invention employs a divider 34 that is horizontally accommodated within the volume formed by the v-shaped plate 20. The dividers should preferably be evenly spaced apart along the length of the v-shaped plate between the outlet holes of the flow tube. The divider 34 contacts the v-shaped plate at the base of the v-shaped plate and at least partially to the side of the v-shaped plate and forms a region 36 in the volume of the v-shaped plate 20. The divider 34 reaches the top of the trough and extends vertically into the space between the flow tube 6 and the v-shaped plate 20, as shown in FIG. 3, perpendicular to the v-shaped plate 20 and the trough 4. High enough to be able to. The contact between the divider 34 and the v-shaped plate 20 is such that liquid does not flow between the divider 34 and the v-shaped plate and does not flow from region to region at least near the base of the v-shaped plate 34. Is. The divider may be triangular in shape to accommodate the volume shape formed by the v-shaped plate 20 (FIG. 5), or the divider 34 may have a regional overflow passage 38 (FIG. 11). In order to be defined, it can be a pentagonal polygon. The regional overflow passage 38 allows liquid to flow from region to region, but only when the liquid head in one region does not rise abnormally high to the level of the regional overflow passage 38. This will prevent the trough from overflowing in the same condition, as well as clogging of the holes in the v-shaped plate with dust. As long as the liquid level remains below the regional overflow passage 38, the liquid flow between the regions 36 is blocked by the divider 34. When the liquid exiting the flow tube 6 has a horizontal component of moment, the liquid impacts the divider 34, drains along the surface of the divider 34, and is held in a specific region 36. Will. The horizontal component of the moment is split so that a more uniform liquid distribution through the holes 22 is achieved.

  A comparative study was conducted to demonstrate the effect of the present invention. Three different devices were compared. The first device did not include a v-shaped plate. Instead, a horizontal flat perforated plate was installed inside the trough to disrupt the liquid flow from the outlet hole of the flow tube to the outlet hole of the trough floor. Similar devices are described in US Pat. No. 5,209,875 and US Pat. No. 5,573,714. The next device included the v-shaped plate of the present invention. The last device had a new v-shaped plate and also had a divider placed vertically in the volume of the v-shaped plate at a position between the outlet holes of the flow tube. Each of the devices was operated in the same state with the same liquid. The performance of each of the devices was analyzed nine times at three different liquid head depths and three different vent hole patterns in the trough floor. Three different discharge hole patterns are labeled as patterns A, B, and C. In each of the experiments, the flow rate of liquid exiting the trough floor drain holes was measured and a% (maximum / minimum) -1 distribution was calculated. The smaller the% distribution, the more uniform the liquid distribution. The collected data is listed in the table.

  As the data shows, the v-plate with the v-plate and the divider showed superior performance compared to another liquid dispensing device. In all but one experiment, it was found that both liquid dispensers with v-plates had a more uniform flow rate than liquid dispensers without v-plates. In many cases, the degree of improvement is dramatic. This example demonstrates that in certain applications, utilizing a v-shaped plate or v-shaped plate with a divider can improve the uniformity of liquid distribution.

Claims (10)

In the liquid dispensing device,
a) at least one elongated trough having a first and second spaced apart side walls (8) interconnected by a floor (12) having a plurality of liquid discharge holes (18) and a second side wall (10); 4) and
b) at least one elongated v-shaped plate having a plurality of holes (22) and disposed between the first side wall (8) and the second side wall (10) of the trough (4); (20) A liquid dispensing apparatus comprising: The liquid dispensing apparatus of claim 1, further comprising a flow tube (6) having an outlet hole (24) , wherein the flow tube is aligned with the trough (4). (6) is a liquid dispensing device located above the trough (4). 2. The liquid dispensing device according to claim 1, wherein the v-shaped plate (20) defines a volume and is arranged vertically within the volume defined by the v-shaped plate (20). The divider (34) defines an overflow passage (38) that defines the volume into a plurality of regions (36) and allows flow between the regions (36). A liquid dispensing device. 4. The liquid dispensing apparatus of claim 3, further comprising a flow tube (6) having an outlet hole (24) , wherein the flow tube is aligned with the trough (4). (6) The liquid distributor, wherein the liquid distributor is located above the trough (4) and the divider (34) is positioned between the outlet holes (24) of the flow tube (6).   The liquid dispensing apparatus according to claim 1, further comprising at least one mass transfer bed (35) adjacent to a liquid discharge hole (18) in the floor (12) of the trough (4). In a method of dispensing a liquid,
a) conducting liquid through a flow tube;
b) draining the liquid from the flow tube through a series of outlet holes in the flow tube;
c) advancing the drained liquid through a hole in the v-shaped plate and into an elongated trough having spaced apart first and second sidewalls interconnected by a floor, the floor comprising a plurality of Having a hole for discharging liquid, the v-shaped plate being disposed between the first side wall and the second side wall;
d) A method of dispensing a liquid comprising the step of advancing the liquid through the liquid discharge hole in the floor of the trough. The method of claim 6, further comprising at least one distillation tray or at least one step that makes contact with the packed bed distributor said liquid from said liquid discharge holes in the floor of the trough, the method.   7. The method of claim 6, comprising guiding the liquid discharged from the flow tube into an area of the v-shaped plate and restricting at least a portion of the liquid flow between the areas. The method further comprises the region defined by a divider positioned vertically within the volume defined by the v-shaped plate and spaced apart between the outlets of the flow tube.   7. The method of claim 6, wherein the liquid is substantially free of horizontal moment components and substantially free of turbulence after traveling through the liquid discharge holes in the floor of the trough. Method.   The method of claim 6, further comprising exhausting steam through the v-shaped plate.

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