FR2637060A1 - Packing elements in layers comprising, on two of their faces, crossed channels and their characteristics - Google Patents

Abstract

Packing element, intended in particular for columns for transferring material, for heat exchange and for mixing two fluids, formed by a layer of material of thickness "E" which is substantially constant between one face A and one face B which are substantially parallel, the said face A comprising at least one open channel and, preferably, a plurality of open channels, of depth Pa, extending completely through, on the said face A overall in a direction AA' and the said face B comprising a plurality of open channels, each having, independently of one another, a depth Pb, extending completely through on the said face B overall in a direction BB' making an angle alpha with the direction AA' of 10 to 170 degrees, and the sum of the depths Pa + Pb being equal to a value from 0.7 to 1.3 times the value of the thickness "E" of the layer. Packing is obtained, for example, by superposing wafers formed by the juxtaposing packing elements juxtaposed such that the channels make an angle greater than zero degrees and less than 90 degrees with the axis of the column into which the said packing is placed.

Description

The present invention relates to packing elements intended in particular for material transfer columns, heat exchange and mixing between at least two fluids.

The present invention also relates to the production of geometrically regular linings making it possible to obtain, for example, distillation and / or absorption columns having a high efficiency and a relatively moderate cost.

The first geometrically regular packings were developed 25 years ago by the SULZER Company. These linings have been the subject of various improvements over time, and more particularly during the last ten years, as evidenced by the number of patent documents published on this subject.

The main object of these various improvements, in the case of distillation columns, is to obtain better separating power and a low pressure drop. Other improvements were aimed at finding new methods of manufacturing these packings which are more efficient and / or easier to implement.

The vast majority of geometrically regular packings and, for example, those described in patent documents
US-A-3679537, EP-B-70917 and EP-A-212202 all have in common the use of a thin sheet material to achieve the creation of a structure comprising series of strips, pleated according to a certain angle, and which are stacked so as to form intersecting open channels and axes oblique to the axis of the column.

The use of thin sheet for the production of column packing elements poses a certain number of problems for the manufacture of these elements and usually requires either the use of particular techniques such as, for example, the use of lost wax molds (EP-A-212202), that is to say the use of materials having particular mechanical characteristics, such as, for example, thin sheet steel which can withstand the shaping necessary for the production of these elements packing; in both cases, the cost of these packing elements is relatively high.

The present invention proposes to overcome these drawbacks.

One of the objects of the present invention is thus to propose a structure of packing elements, which can be manufactured in a simple manner, and at low cost, for each column diameter, and which has from the mechanical point of view a great solidity and good stability.

Another object of the present invention is to provide a structure of packing elements allowing the use of certain materials, for example wood, which are difficult to use for manufacturing the structures of the prior art, for example those described in the document US -A-3679537.

The structure of the packing elements of the present invention also makes it possible to obtain, for example, ceramic packings of a significantly increased strength compared to that of the ceramic packings described, for example, in patent document EP-A -212202 and, moreover, it is possible to obtain packings having channels in the three directions of space while retaining good solidity with these packings. The linings, which have channels in the three directions of space, usually allow better contact between the fluids, for example, between a gaseous fluid and a liquid fluid and therefore an easier mixing of the two fluids.

The various objects which the invention has set for itself are achieved by the measures proposed, in the characterizing part of claim 1, for the packing element, intended in particular for material transfer, heat exchange and mixing columns. between at least two fluids.

According to a preferred embodiment of the solid lining element formed by a layer of material, of thickness "E" substantially constant between a face A and a face B substantially parallel, each of the faces A and B comprises a plurality of channels of directions AA 'and BB' respectively, said directions AA 'being substantially parallel to each other and, consequently, said directions
BB 'being substantially parallel to each other and forming an angle alpha, with said directions AA', equal to a value of 10 to 170 degrees, preferably from 20 to 160 degrees and most often from 60 to 120 degrees.

The packing element of the present invention usually has the form of a convex polyhedron, having two substantially parallel faces defining a layer of thickness "E", for example a hexahedron such as a cube or a parallelepiped. The thickness "E" of the material layer can be very variable, but is usually from about a few thousandths of a millimeter to about a few tens of centimeters, usually from about 10 5 (m) meter to 0.8 m and the more often about 2.10 5 m to 0.5 m. The channels on each of the faces A and B are preferably substantially rectilinear and preferably each each have independently a section formed by a polygon or a curvilinear polygon, one of which rib belongs to the plane determined by the face comprising said channel, said rib corresponding to the opening of said channel. The section of a channel will be, for example, triangular, trapezoidal, square, in the form of a segment of a circle such as, for example, in a semicircle, of a segment of ellipse or of a parabola. The channel section usually has an area of about 10 10 to about 10 1 (m2) square meter, squvent of about 2x1 "'8 to 2 x 10'2 m2 and most often about 5 x 10 to approximately 10-2 m2.

The channel (s) AA 'have a depth Pa which can be variable throughout a channel and also from one channel to another, and which is preferably substantially constant throughout a channel for each of them. The direction channels BB ′ have a depth Po which can be variable throughout a channel and also from one channel to another, and which is preferably substantially constant throughout a channel for each of between them.

The sum of the depths Pa + Pb of the channel or of the direction channels (AA ') and of the direction channels (BB') measured, preferably at each point of intersection of a direction channel AA 'with a direction channel BB ', is equal to a value of 0.7 to 1.3 times the value "E" of the thickness of the layer of material forming the lining element. We can thus distinguish two embodiments, the first in which the sum of the depths Pa + Pb is for each of the channels at most equal to the thickness "E" of the layer of material, ie from 0.7 to 1 time, often from 0.7 to 0.95 times and most often from 0.8 to 0.9 times the "E" value of the thickness of the material layer, and the second in which the sum of the depths
Pa + Pb is, for at least one channel of side A and at least one channel of side B, the directions of which cross in the volume defined by the lining element, at least equal to the thickness "E" of the material layer, ie from 1 to 1.3 times, often from 1.01 to 1.25 times and most often from 1.1 to 1.2 times the "E" value of l thickness of the material layer.

In an advantageous embodiment, the channel or channels of side A and all the channels of side B have substantially the same depth P. In another embodiment, all the channels of side A have substantially the same depth Pa and, for example, one channel in two or one channel in three or one channel in four of the face
B, has a depth Pbl such that the sum Pa + Pbl is greater than 1 time the thickness "E" of the layer of material, the others having a depth Pb2, such that the sum Pa + Pb2 is less than I times l thickness "E" of the layer of material. In another embodiment, certain channels of side A and certain channels of side B, for example, one channel in two or one in three or one in four, respectively a depth Pal and Pbl, the other channels having a depth Pa2 and b2, said depths being such that the sums Pal + Pbl, Pal + Pb2 and Pbl + Pa2 are greater than once the thickness "E" of the layer of material and the sum Pa2 + Pb2 is less than the thickness "E" of the layer of matter, or or such that the sums Pal + Pb2, Pa2 + Pbl and Pa2 + Pb2 are less than once the thickness "E" of the material layer and the sum Pal + Pbl is greater than the thickness "E" of the material layer.

In the last two embodiments, there is formation of communication passages between side A and side B of the packing element, said passages or holes have a section, the shape of which depends on the shape of the section of each of the channels at their crossing point. By way of example, these holes have a diamond-shaped section in the case where the channels at their crossing point have a triangular section. The cross-sectional area of the passages or holes depends on the respective depths of the channels at the crossing point where the said passage is created.

In a preferred embodiment, the channels of each face are preferably distributed in a substantially regular manner on said face; an irregular distribution is however not excluded and would fall within the scope of the invention. The channels can be adjacent to the opening, which corresponds to ridges of very small width, or even practically zero. The channels can be separated from each other by a distance "d", in this case the ridges will have a width "d" usually from about 0.01 millimeter (1C meter) to about 10 centimeters (lO-l meter) and, most often, from about 0.1 millimeter (10 4 m) to about 5 centimeters (0.5 x 10 meters).

In the present invention, the channels may have smooth, ribbed, bumpy or rough walls and, preferably, the walls of the channels will be ribbed, bumpy or rough; in the most preferred embodiment, the walls will be rough. They may also have alternately smooth and striated and / or bumpy and / or rough walls.

The material for manufacturing the packing element can be any of the materials well known to those skilled in the art and employed in the prior art for manufacturing column packing elements. By way of nonlimiting examples of usable materials, mention may be made of plastics, wood, concrete, metals, and ceramics, porous or not, in fibers or dense, the fibers possibly being compressed or not, added together. optionally organic or mineral binders. Ceramics can also be ceramic-ceramic fiber or ceramic-metal fiber composites. Concrete can be refractory concrete, concrete with additives that modify some of its properties, for example, organic polymers, epoxy adhesives, etc. ..; it can also be a concrete comprising metallic reinforcements or glass fibers or synthetic fibers, for example, Kevlar (registered trademark of the Company DUPONT DE NEMOURS). One can also use a composite material based on concrete, for example, Eternit (registered trademark of the company ETERNIT).

In an advantageous embodiment of the present invention, the surfaces of the walls of the channels can be modified, for example by treatments using lipophilic or hydrophilic products, by treatments using wetting agents, by deposits of coke or of active principles such as, for example, a catalyst or at least one element with catalytic action. This surface modification can be carried out, on the lining elements forming a layer or even on the entire lining, by any means known to a person skilled in the art for effecting such depits or surface modifications of a material.

In the case of coke, the material will, for example, be impregnated with a hydrocarbon cut, then will be heated so as to transform into coke the hydrocarbons adsorbed on the material.

The present invention also relates to a column packing formed by a juxtaposition of packing elements such as those described above.

In a preferred embodiment of the column packings, the packing elements are arranged so that the axes of the channels each make, independently of each other, an angle with the axis of the column greater than zero degrees and less than 90 degrees, preferably less than 60 degrees and most often less than 45 degrees.

The packing elements are usually juxtaposed so
that the channels of side B of a given element is opposite the channels of side A of the element which immediately follows it, said channels forming between them an angle of approximately 10 to 170 degrees, preferably of approximately 20 to 160 degrees and most often around 60 to 120 degrees.

The packing of the column can be formed of a single wafer of packing elements having a height H equal to the height H of the packing or of several successive wafers superimposed each having, independently of each other, a height h less than H , and the sum of the heights h being equal to HA by way of example, the packing of the column can be formed by the superposition of n wafers each having substantially the same height h equal to H / n, n being an integer at less equal to-. 2. In the case of the superposition of several wafers (at least two), the planes of the filling elements forming the wafer of rank p + 1 located immediately above the wafer of rank p, form an angle with the planes of the elements lining the wafer of rank p from zero to 90 degrees, for example an angle equal to zero or 90 degrees; p is an integer having a value of 1 a n-l, n being the number of wafers forming the filling.

The channels of each of the faces of a lining element of the wafer of rank p + l can form with the axis of the column an angle having a value chosen from the range defined above and equal to the value of the angle formed by the channels of each of the faces of a lining element of the wafer of rank p with this same axis. It is also possible, for example in the case where the planes of the lining elements of the wafer of rank p and that of rank p + l make an angle equal to zero degrees, that the axes of the channels of each of the faces of a lining element of the wafer of rank p make with the axes of the channels of each of the faces of the element opposite the wafer of rank p + l, respectively for each face, for example, an angle of zero to 90 degrees, each channel taken separately making an angle with the axis of the column having a value chosen from the range defined above.

In a preferred embodiment of the lining, each pancake will be surrounded by at least one member having the function of ensuring the centering of the pancakes in the column, as well as of bringing back towards the interior of the pancake the liquid which flows on the wall of the column, this member may for example be a metal sheet forming a corolla around the cake.

The accompanying drawings illustrate the invention but should not be considered as limiting.

In the various figures, similar bodies are designated by the same numbers or reference letters.

FIG. 1 represents, in perspective, a lining element forming a layer of material of thickness "E" comprising on the face A a channel of axis AA 'and of depth Pa, and on the face B a plurality of channels of axes BB 'and depths Pb; the axes BB 'are substantially parallel and make an axis alpha of about 90 degrees with the axis AA'.

FIG. 2 represents, in perspective, a packing element formed by a layer of material of thickness "E" comprising a plurality of channels, on the side A and on the side B, regularly spaced and whose crests have on the side At a width "da" and on the side B a width "db", "da" and "db", equal or different between them, having values included in the range defined above for the width "d"
Figures 3, 4 and 5 each show, in section, the structure of a packing element. In the case of FIGS. 3 and 4, the ridges of the channels of face A have a practically zero width; the channels have in FIG. 3 a uniform depth Pa, and, in FIG. 4, one channel in three has a depth Pal or Pbl, the others having a lower depth Pa2 or Pb2. In FIG. 5, the channels have a sinusoidal section.

In Figure 6, there is shown, in perspective, a lining formed by the juxtaposition of two lining elements "a" and "b" (each lining element is identical to that shown schematically in Figure 2) whose faces A and B respectively are opposite; the axes AA 'of the channels of the face A of the element "a" making a delta angle of approximately 90 degrees with the axes BB' of the channels of the face B of the element "b".

FIG. 7 is a perspective view of a packing element comprising, on the face A, a plurality of channels, of axes AA 'and of uniform depth Pa, regularly distributed, the crests of which have a width "da", and comprising on the side B a plurality of channels, axes BB ′ and depth Pbl for one channel in three, and of depth Pb2 for the others; the sum of the depths Pa + Pbl is greater than the thickness "E" of the layer of material and the sum of the depths Pa + Pb2 is less than the thickness "E" of the layer of material. BB 'axis channels are regularly spaced on the face
B and the ridges have a width "db". A section along the XY plane of this packing element is shown diagrammatically in FIG. 8, which shows the shape, in rhombus, of the shaped passages, between the face A and the face
B of said packing element, at the crossings - of the depth channels Pbl of the face - B with the channels of the face A.

Figure 9 shows schematically, in perspective, the juxtaposition of several packing elements in order to form a wafer of height "h".

The various packing elements have been represented in a simplified manner with the aid of straight prisms having a generator direction which is substantially vertical and parallel to the axis of the column, in the XY plane formed by the axes of the channels and forming a non-zero angle. with each of the axes AA 'and BB' of said channels. Each packing element (1) has a different size which depends on the geometry of the column. Thus, for example, in the case of a cylindrical column, the juxtaposition of the packing elements (1) of appropriate size will form a cylindrical packing.

Figure 10 shows schematically a wafer of height "h" comprising several packing elements (1) and comprising two members "C1" and "C2" each formed by a sheet material comprising a series of slots "F", regularly spaced, on a part of the height of the sheet and making it possible to form, by folding towards the outside of the cake, a corolla comprising a series of elements or petals "F1" around the cake.

FIG. 10A illustrates, in more detail, the structure of a part of a member "C1" comprising a series of slots "F", over approximately half of its width "1", which define the petals "F1" .

FIG. 11 illustrates a column "K" comprising two pancakes G1 and
G2 superimposed, so that the planes of the packing elements (1) of the wafer G1 make an angle of 90 degrees with the planes of the packing elements (1) of the wafer G2. The material in the form of a thin sheet, comprising slits "F" limiting the petals "F1", and disposed at the two ends of each wafer, on their periphery, is deployed and forms a corolla whose petals "F1" rest on the walls of column "K".

Depending on the material, the means of production and the size of the installation for which these packing elements are intended, it is also possible to envisage having a monolithic piece of height 0.05 ma 15 met in diameter from 0.01 m to 10 m, or a series of monolithic pieces, usually identical, each forming a wafer having, for example, a height of 0.01 m to 3 m and a diameter of 0.01 m to 10 m, which are preferably superimposed that the upper face of one is in contact with the lower face of the other and which thus form the lining of the column "K".

The packing elements of the present invention, having the particular geometric structure described above, can easily be produced in large series, for example by molding, in particular in the case where the material used is a plastic material, concrete or ceramic. Another advantage of these packing elements is the ease with which they can, after manufacture, be cut to the desired dimensions. The packing elements of the present invention can also be manufactured by any other method well known to those skilled in the art, for example, by grooving or stamping.

Claims (13)

1 - Packing element, characterized in that it is formed of a layer of material of thickness "E" substantially constant between a face A and a face B substantially parallel, said face A comprising at least one open channel, depth Pa, extending right through on said face A, generally in a direction AA 'and said face B comprising a plurality of open channels, each having a depth Pb, extending independently of each other, of right through, on said face B generally in a direction BB 'making an angle alpha with the direction AA' from 10 to 170 degrees and the sum of the depths Pa + Pb being equal to a value of 0.7 to 1.3 times the value of the thickness "E" of the layer of material. 2 - Packing element according to claim 1, characterized in that each of the faces A and B comprises a plurality of channels, the angle between the directions AA 'and BB' of said channels being from 20 to 160 degrees. 3 - Packing element according to claim 1 or 2, characterized in that the channels are substantially rectilinear. 4 - Packing element according to one of claims 1 to 3, characterized in that the channels have, each independently of one another, a substantially constant depth over their entire length. 5 - Packing element according to one of claims 1 to 4, characterized in that the channels each have, independently of each other, a section formed by a polygon or a curvilinear polygon, one side of which belongs to the plane determined by the face comprising said channel. 6 - Packing element according to one of claims 1 to 5, characterized in that the section of the channels has an area of about 10 10 m2 to about 10'1 m2. 7 - lining element according to one of claims 1 to 6, characterized in that the sum of the depths Pa + Pb of each of the channels at their crossing points is at most equal to the thickness "E" of the layer of matter. 8 - Packing element according to one of claims 1 to 6, characterized in that the sum of the depths Pa + Pb is, for at least one channel of the side A and at least one channel of the side B at their points crossing, at least equal to the thickness "E" of the layer of material. 9 - Packing element according to one of claims 1 to 8, characterized in that the channel or channels of side A and all the channels of side B have substantially the same depth P. 10 - Packing element according to one of claims 1 to 9, characterized in that the surfaces of the walls of the channels are modified by treatment with lipophilic or hydrophilic products or wetting agents.  it - packing element, according to one of claims 1 to 10, characterized in that the surfaces of the channel walls are modified by deposition of a catalyst or at least one element with catalytic action. 12 - Packing of the column characterized in that it is formed by a juxtaposition of packing elements according to one of claims 1 to 11, said elements being juxtaposed so that the channels of directions BB 'd' a side B of an element is opposite the channel or channels do direction AA 'of a face A of the neighboring lining element, said directions BB' and AA 'forming between them an angle of 10 to 170 degrees. 13 - Column packing according to claim 12, wherein the packing elements are arranged so that the directions of the channels each make, independently of each other, an angle with the axis of the column greater than zero degrees and less than 90 degrees. 14 - Use of at least one packing element, according to one of claims 1 to 11, or the packing, according to claim 12 or 13, in the material transfer columns, heat exchange or mixture between at minus two fluids.