FALSE DOWNCOMER LIPS

Abstract

Embodiments of false downcomers are described having a lip extending inwardly from a bottom portion of the wall of the false downcomer. The lip has a length sufficient to deflect downward vapor from exiting through the bottom opening.

Claims

1. A false downcomer, comprising: a first wall that at least partially defines a bottom opening; and a first lip extending from a bottom portion of the first wall that at least partially defines a perimeter of the bottom opening, wherein the first lip has a length sufficient to deflect downward vapor from exiting through the bottom opening.

2. The false downcomer of claim 1, wherein the first wall has a downward slope.

3. The false downcomer of claim 1, further comprising a second wall coupled to the first wall, and that at least partially defines the bottom opening.

4. The false downcomer of claim 1, wherein the first lip extends generally horizontally from the bottom portion of the first wall.

5. The false downcomer of claim 1, wherein the first lip extends normally from the first wall.

6. The false downcomer of claim 1, wherein an angle of intersection between the first lip and first wall is greater than 90 degrees.

7. The false downcomer of claim 1, wherein the length of the lip is between 40-60 mm.

8. The false downcomer of claim 1, wherein the first wall comprises a vertical portion and a sloped portion, and wherein a length of the vertical portion is equal to the length of the first lip.

9. The false downcomer of claim 1, wherein the first lip effectively reduces an area of the bottom opening.

10. The false downcomer of claim 1, wherein a height of the first wall is no greater than 350 mm.

11. A false downcomer, comprising: an outer wall that at least partially defines an opening; and a projection extending within the opening from a bottom of the outer wall, and wherein the projection at least partially defines a perimeter of the opening.

12. The false downcomer of claim 11, wherein the projection has a length sufficient to deflect downward vapor from exiting downward through the opening.

13. The false downcomer of claim 11, wherein the projection extends along a horizontal plane from the bottom of the outer wall.

14. The false downcomer of claim 11, wherein the projection extends normally from the outer wall.

15. The false downcomer of claim 11, wherein the length of the lip is between 40-60 mm.

16. The false downcomer of claim 11, wherein the outer wall comprises upper and lower portions, and wherein the upper portion is disposed vertically and the lower portion is sloped inwardly with respect to the upper portion, and wherein the projection extends inwardly with respect to the outer wall and in a direction that is normal to the upper portion.

17. The false downcomer of claim 16, wherein a length of the upper portion is equal to a length of the projection.

18. The false downcomer of claim 11, wherein a height of the first wall is no greater than 350 mm.

19. An absorption tower, comprising: a housing that defines an interior cavity; a fluid distributor configured to feed a feed or reflux stream into the interior cavity; a false downcomer disposed within the housing and configured to distribute the feed or reflux stream to packing disposed below the false downcomer; and wherein the false downcomer includes a lip that projects inwardly from an outer wall of the false downcomer.

20. The absorption tower of claim 19, wherein the lip has a length sufficient to deflect downward vapor from exiting downward through a bottom opening of the false downcomer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 is a schematic of a prior art false downcomer.

[0019] FIG. 2 is a schematic of one embodiment of a false downcomer of the inventive subject matter.

[0020] FIG. 3 is a schematic of another embodiment of a false downcomer of the inventive subject matter.

[0021] FIG. 4 is a schematic of an embodiment of an absorption tower having a false downcomer.

DETAILED DESCRIPTION

[0022] The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.

[0023] In FIG. 2, a vertical cross-section of a schematic of one embodiment of a false downcomer 200 is shown having walls 204, 205 that at least partially define a bottom opening 201 of the false downcomer, as well as an interior space within.

[0024] False downcomer includes short, horizontal lips 202, 203 or other projections at the bottom of each wall 204, 205 of the false downcomer 200, which at least partially defines a perimeter of the bottom opening 201. The lips 202, 203 preferably extend inwardly and toward one another. It is especially preferred that the lips 202, 203 comprise a single piece that extends inwardly from a perimeter of the wall 204 of the false downcomer 200. The lips 202, 203 preferably have a length sufficient to help prevent downward vapor from exiting through the bottom opening and deflect it upwardly. In this manner, the lips 202, 203 advantageously deflect any downward vapor horizontally, forcing it back into the false downcomer 200 instead of allowing it to hit the liquid surface below. As a result, the angle of issue of the fluid jet from the distributor pipe can be increased without the vapor missing the downcomer and hitting the liquid surface below. This allows for an absorption or other tower to be retrofitted without necessitating the tray spacing to be increased at the feed zone.

[0025] Although the precise dimensions can vary depending on the specific application, it is preferred that lips 202, 203 have a length of between 20-70 mm, and more preferably between 40-60 mm. As shown in FIG. 2, lips 202, 203 can each have a length of approximately 50 mm. However, it is also contemplated that the lips 202, 203 could each have a length of approximately 25 mm in some applications. The lips 202, 203 effectively reduce the diameter of the bottom opening 201 of the false downcomer 200.

[0026] It is also contemplated that the walls 204, 205 could compose a single piece and a unitary structure that defines an interior of the false downcomer 200. Thus, for example, a lip 202 can extend from wall 204, and preferably extends inwardly toward an interior of the false downcomer 200.

[0027] The walls 204, 205 can either be vertical or sloped walls, or a combination thereof. Sloped walls are often used when the feed is a flashing feed. Sloping the walls gives an opening large enough between the false downcomer wall and the inlet pipe to permit vapor ascent without much entrainment of liquid, while minimizing the area on the tray or distributor below that is consumed by the false downcomer or its footprint. As shown in FIG. 2, walls 204, 205 can each include a vertical upper portion and a sloped lower portion. In such embodiments, it is preferred that the lips 202, 203 extend in a direction that is normal to the vertical upper portion.

[0028] In some contemplated embodiments, an angle of intersection between the lip 202 and wall 204 is greater than 90 degrees.

[0029] In other contemplated embodiments, a length of the vertical upper portion of wall 204, for example, can be equal to a length of lip 202. It is further contemplated that the height of the wall and/or false downcomer 200 is no greater than 350 mm, although the specific dimensions will vary depending on the application.

[0030] The false downcomer 200 can be used in any distillation or absorption tower (e.g., new design or retrofit) when the feed is a flashing feed. The false downcomer 200 has many benefits when the tray spacing at the feed region is short and there is economics to prevent increasing this height. For example, in a retrofit, the false downcomer 200 will permit achieving an effective design which may not be possible without it if the spacing at the feed is short. In a new tower, the false downcomer 200 may permit a small reduction (about 300 mm) in tower height.

[0031] In FIG. 3, another embodiment of a false downcomer 300 is shown having a lip 302 extending from an outer wall 304 of the false downcomer 300. Rather than lie along a horizontal plane as in FIG. 2, lip 302 is downwardly sloped while still extending inwardly with respect to outer wall 304. With respect to the remaining numerals in FIG. 3, the same considerations for like components with like numerals of FIG. 2 apply.

[0032] FIG. 4 illustrates one embodiment of an absorption tower 410 having a false downcomer 400. The tower 410 preferably includes an outer housing 412 that defines an interior cavity 414. A fluid distributor 416 is at least partially disposed within the outer housing 412 and configured to feed a feed or reflux stream into the interior cavity 414. The false downcomer 400 can also be positioned within the interior cavity 414 such that the false downcomer 400 receives the feed or reflux stream, and distributes the feed or reflux stream to packing, etc. disposed below the false downcomer 400. Preferably, the false downcomer 400 includes a lip extending from its bottom portion that projects inwardly from an outer wall 404 of the false downcomer 400. With respect to the remaining numerals in FIG. 4, the same considerations for like components with like numerals of FIG. 2 apply.

[0033] As used herein, and unless the context dictates otherwise, the term “coupled to” is intended to include both direct coupling (in which two elements that are coupled to each other contact each other) and indirect coupling (in which at least one additional element is located between the two elements). Therefore, the terms “coupled to” and “coupled with” are used synonymously.

[0034] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0035] Unless the context dictates the contrary, all ranges set forth herein should be interpreted as being inclusive of their endpoints and open-ended ranges should be interpreted to include only commercially practical values. Similarly, all lists of values should be considered as inclusive of intermediate values unless the context indicates the contrary.

[0036] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.

[0037] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value with a range is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.

[0038] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.

[0039] It should be apparent to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refers to at least one of something selected from the group consisting of A, B, C . . . and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc.