Patent Publication Number: US-2022233970-A1

Title: Column for exchanging heat and/or mass

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a 371 of International Application No. PCT/EP2020/06322, filed May 12, 2020, which claims priority to French Patent Application No. 1905124, filed May 16, 2019, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     The field of the present invention is that of columns for exchanging heat and/or mass and, more particularly, devices for retaining heat exchange means and/or mass exchange means arranged in such columns. 
     Heat and/or mass exchange columns are today used in a wide variety of processes. For example, heat and/or mass exchange columns allow scrubbing processes, cooling processes, heating processes or distillation processes to be implemented. All of these processes are based on a single basic principle, namely the exchange of heat and/or of mass between two fluids. These two fluids may, for example, be two liquids, two gases, or else a liquid and gas. 
     Such columns thus comprise at least one heat and/or mass exchange means through which the two fluids pass and in which the exchange of heat and/or of mass between these two fluids take place. Conventionally, these heat and/or mass exchange means rest on a support element which may be secured directly inside the heat and/or mass exchange column concerned, or more particularly on a peripheral wall of this heat and/or mass exchange column, or which may rest against a structural element, itself secured to the peripheral wall of the heat and/or mass exchange column. 
     One disadvantage with the current support elements notably lies in the fact that their retention in the heat and/or mass exchange column is governed by a step of fixing, for example brazing or welding, this support element, or the structural element against which it rests, into the heat and/or mass exchange column. 
     SUMMARY 
     The present invention falls within this context and seeks to alleviate at least this disadvantage by proposing a device for retaining a heat and/or mass exchange means that is simple and inexpensive in terms of manufacture, configured to support this heat and/or mass exchange means without having to be secured to the heat and/or mass exchange column. 
     One subject of the present invention thus relates to a heat and/or mass exchange column comprising at least one peripheral wall delimiting an internal volume in which there are arranged at least one heat exchange means and at least one retaining device for retaining the heat and/or mass exchange means, the device comprising at least two flexible strips in which there are formed at least two cutouts, the strips extending predominantly in a main direction of extension between two longitudinal ends. According to the invention, the cutouts are configured to adjust a dimension of elongation of the strips, in said main direction of extension, to suit a dimension of the heat and/or mass exchange column. In other words, the cutouts made in the strips give these strips an elasticity which, on the one hand, allows the strip to be introduced into the heat and/or mass exchange column for which it is intended and, on the other hand, ensures that these strips are retained in this heat and/or mass exchange column once they have been positioned therein. 
     In addition, at least the longitudinal ends of the at least one strip bear against the peripheral wall. 
     According to one feature of the present invention, the two longitudinal ends are joined together by two transverse edges and the cutouts are respectively formed closer to one of the longitudinal ends of the strip than to a center of this strip, What is meant by “center of the strip” is a point on this strip that is equidistant from the two longitudinal ends of this strip and also equidistant from the two transverse edges of this strip. Advantageously, provision may be made for a cutout to be formed near each longitudinal end of the strip, namely one cutout is then formed nearer to one of the longitudinal ends of the strip than to the center of this strip, and the other cutout is formed nearer to the other longitudinal end than to the center of the strip. 
     According to one particular embodiment of the present invention, the two transverse edges of the strip are parallel to one another, which is to say that, according to this particular embodiment, the strip has a substantially rectangular shape. 
     According to one feature of the present invention, each cutout extends from one of the transverse edges of the strip. Advantageously, the strip comprises at least four cutouts distributed in pairs, each pair of cutouts being formed closer to a longitudinal end of the strip than to the center of this strip. For example, the two cutouts of one pair of cutouts extend respectively from opposite transverse edges of the strip. In other words, according to this example, the two cutouts of each pair of cutouts are formed top to tail. It will be appreciated that the greater the number of cutouts formed in the strip, the greater will be the elasticity of this strip. 
     According to one feature of the present invention, at least one longitudinal end of the strip has at least one chamfer. Advantageously ;  at least one longitudinal end of the strip has two chamfers joined together by a ridge. More advantageously still, the two longitudinal ends of the strip each have two chamfers joined together by a ridge. These chamfers are notably configured to facilitate insertion of the retaining device according to the invention into the heat and/or mass exchange column for which it is intended. 
     According to one embodiment of the present invention, the retaining device comprises at least two strips. For example, these two strips may intersect. According to one embodiment of the present invention, these strips intersect substantially at their center, which is to say at a point equidistant from the two longitudinal ends of the strip concerned. Thus, according to this embodiment, these strips may for example be arranged in an X or in a cross. 
     According to another embodiment of the present invention, the retaining device comprises at least four strips which form a lattice. Advantageously, these strips may be parallel in pairs. Even more advantageously still, provision may be made for at least two strips to extend predominantly in a first direction, and for at least two strips to extend predominantly in a second direction, the first direction being perpendicular to the second direction. What is meant by “at least two strips extend predominantly in a first direction” and “at least two strips extend predominantly in a second direction” is that the two strips concerned extend in two directions which are parallel to the first direction or to the second direction. Advantageously, these strips may thus form a square grid pattern, which is to say that the strips delimit rectangular or else square openings. 
     It must be understood that the size of the retaining device may be adapted by altering the number of strips and/or at least one dimension of a strip. The dimensions of this retaining device can thus be increased or decreased by adding strips in one direction or in the other, that is to say by adding strips that extend predominantly in the first direction or in the second direction. Advantageously, the retaining device according to the present invention is thus easily adaptable to suit all types of heat and/or mass exchange columns. 
     According to one feature of the present invention, at least one strip comprises at least one slot configured to accept another strip. In other words, it will be appreciated that these strips fit into one another. For example, the at least one slot may have a dimension equivalent, or substantially equivalent, to a transverse dimension of the strip that it accepts, namely a dimension measured parallel to a straight line perpendicular to the main extension direction of the strip concerned. Advantageously, each strip may comprise at least two slots, each slot being configured to accept another strip. Even more advantageously still, each strip may comprise more than two slots, each of these slots being intended to accept a strip. 
     The retaining device according to the invention is intended to be incorporated into a heat and/or mass exchange column, itself intended for a heat and/or mass exchange apparatus which comprises the heat and/or mass exchange column or several heat and/or mass exchange columns possibly assembled with one another. 
     According to the invention, the strips of the retaining device may comprise a mass of which the melting point is higher than the maximum operating and/or manufacturing temperature of such a heat and/or mass exchange column, for example mass of which the melting point is higher than 500° C. 
     Advantageously, that makes it possible to avoid any deformation or deterioration of the retaining device according to the invention during the course of operating and/or manufacturing these heat and/or mass exchange columns. For example, the strips may be made of stainless steel. 
     Advantageously, only the longitudinal ends of the strips of this retaining device bear against the peripheral wall of the column. It will further be appreciated that, in order to be able to bear against the peripheral wall of the heat and/or mass exchange column, each of the strips of the retaining device according to the invention has a longitudinal dimension, which is to say a dimension measured between its two longitudinal ends, parallel to the main extension direction of the strip concerned, that is greater than a cross section of the column, namely a dimension of this column that is measured between two opposite points on the peripheral wall thereof. As these strips are also flexible, inserting them into the column causes elastic deformation of these strips, and once in position in the column, they tend to revert to their original shape. As a result, the longitudinal ends of each strip apply force to the peripheral wall of the heat and/or mass exchange column, thus maintaining the position of the retaining device in the heat and/or mass exchange column. In other words, the mechanical securing of the retaining device according to the invention in the heat and/or mass exchange column requires no additional fixing means. 
     According to one feature of the present invention, at least two strips of the retaining device have a transverse edge that can be inscribed in a plane against which the heat and/or mass exchange means rests. In other words, this plane forms a bearing surface intended to accept at least the heat exchange means. Advantageously, at least one transverse edge of each strip can be inscribed in this plane. In other words, the heat and/or mass exchange means therefore rests on at least one transverse edge of each strip. 
     It will be appreciated from the foregoing that, when the retaining device is arranged in the heat and/or mass exchange column for which it is intended, the cutouts formed in the strips are arranged as dose as possible to the peripheral wall of this heat and/or mass exchange column. These cutouts contribute to the elasticity of the strips and, therefore, also contribute to generating the forces mentioned hereinabove which maintain the position of the retaining device according to the invention in the heat and/or mass exchange column for which it is intended. 
     According to one feature of the present invention, the heat and/or mass exchange column extends predominantly along a main extension axis, the heat and/or mass exchange column comprising at least two retaining devices arranged one on each side of the at least one heat and/or mass exchange means along the main extension axis. Advantageously, that allows the heat and/or mass exchange means to be retained in the heat and/or mass exchange column regardless of the position in which this column is situated. In other words, that ensures the position of the heat and/or mass exchange means along the main extension axis of the heat and/or mass exchange column in which it is arranged. For example, this heat and/or mass exchange column is thus easier to transport. 
     Optionally, at least one mesh structure may be arranged between the heat and/or mass exchange means and at least one retaining device according to the invention. Advantageously, such a mesh structure prevents the heat and/or mass exchange means that is resting on the retaining device according to the invention from passing through the latter. In other words, this mesh structure then rests against the bearing surface formed by the plane in which a transverse edge of at least two strips of the retaining device according to the invention can be inscribed. Such a mesh structure will thus be fitted when the heat and/or mass exchange means comprises one or more elements the dimensions of which are smaller than the spacing between two strips. For the same reasons as those mentioned hereinabove, this mesh structure may advantageously be made from a mass of which the melting point is higher than 500° C. According to one embodiment of the present invention, the mesh structure is made from the same mass as the retaining device according to the invention. 
     It will be appreciated that if the column comprises two retaining devices according to the present invention, then provision may be made for at least one mesh structure to be arranged between each retaining device and the heat and/or mass exchange means around which they are distributed. In other words, the heat and/or mass exchange means is then in contact with two mesh structures, themselves respectively arranged in contact with a retaining device according to the invention. 
     According to the invention, the at least one heat and/or mass exchange means comprises beads and/or plates extending predominantly in a direction parallel to the main extension axis of the column and/or structured packings and/or random packings, 
     The present invention also relates to a heat and/or mass exchange apparatus comprising at least one heat and/or mass exchange column according to the invention, According to the invention, the heat and/or mass exchange apparatus may comprise at least one liquid inlet and at least one gas inlet which are distributed on either side of the heat and/or mass exchange means arranged in the column, along the main extension axis of this heat and/or mass exchange column. 
     According to one feature of the present invention, the heat and/or mass exchange apparatus also comprises at least one liquid outlet and at least one gas outlet which are distributed on either side of the heat and/or mass exchange means arranged in the column, along the main extension axis of this heat and/or mass exchange column. Advantageously, the gas outlet and the liquid inlet are both at one end of the heat and/or mass exchange column, while the liquid outlet and the gas inlet are arranged at the other end of the heat and/or mass exchange column. 
     The present invention relates finally to a heat and/or mass exchange process using a heat and/or mass exchange apparatus according to the invention, wherein the process is a scrubbing and/or cooling and/or heating and/or distillation and/or treatment process. According to one particular embodiment of the present invention, the process may be a cryogenic distillation process. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a further understanding of the nature and objects for the present invention, reference should be made to the following detailed description, taken in conjunction with the accompanying drawings, in which like elements are given the same or analogous reference numbers and wherein: 
         FIG. 1  is a partial view, in vertical section, of a heat and/or mass exchange column according to the invention, this  FIG. 1  showing a heat and/or mass exchange means and a retaining device for retaining this heat and/or mass exchange means according to the invention; 
         FIG. 2  is a partial view, in vertical section, of the heat and/or mass exchange column according to the invention, this  FIG. 2  illustrating a heat and/or mass exchange column in which there are arranged a heat and/or mass exchange means and two retaining devices for retaining this heat and/or mass exchange means according to the invention; 
         FIG. 3  is a perspective illustration of a first embodiment of the retaining device for retaining the heat and/or mass exchange means according to the present invention; 
         FIG. 4  is a perspective illustration of a second embodiment of the retaining device for retaining the heat and/or mass exchange means according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     In the remainder of the description, the terms “heat and/or mass exchange means” and “exchange means” will be used without distinction. Similarly, the terms “heat and/or mass exchange column” and “column” will be used without distinction, as will the terms “heat and/or mass exchange apparatus” and “apparatus”. A vertical direction corresponds to a main direction of extension of a heat and/or mass exchange apparatus according to the invention, when this apparatus is in a functional position, i.e. a position in which a heat and/or mass exchange can take place. 
       FIGS. 1 and 2  each illustrate, partially and in vertical section, a heat and/or mass exchange column  200  according to the invention, these  FIGS. 1 and 2  notably showing a heat and/or mass exchange means  230  and at least one retaining device  240  for retaining this heat and/or mass exchange means  230  according to the invention. What is meant by “vertical section” is a section made on a plane in which a main extension axis X of the column  200  can be inscribed. 
     Such a heat and/or mass exchange column  200  may be used for heating and/or for cooling and/or distillation and/or for stripping and/or for scrubbing and/or for treatment. It may for example be a cryogenic distillation column, for example intended for the cryogenic distillation of air. 
     This heat and/or mass exchange column  200  extends predominantly along a main extension axis X and is intended to be assembled with other heat and/or mass exchange columns to form a heat and/or mass exchange apparatus not illustrated here. Such a heat and/or mass exchange apparatus may be configured to allow an exchange of heat and/or of mass between two fluids. For example, the apparatus can thus be configured to allow an exchange of heat and/or of mass between a liquid that circulates in the apparatus in a first direction and a gas that circulates in the apparatus in a second direction, It is understood that any other process for the exchange of heat and/or mass between two fluids can be implemented by the apparatus according to the invention without departing from the context thereof. For example, the apparatus can be configured to implement a scrubbing process and/or a cooling process and/or a heating process and/or a distillation process and/or a treatment process. In any case, the apparatus according to the invention comprises at least one inlet for the first fluid, for example a liquid inlet, and at least one inlet for the second fluid, for example a gas inlet, these fluid inlets not being depicted in the figures described here. Likewise, the apparatus may comprise at least one outlet for a third fluid and/or at least one outlet for a fourth fluid. 
     As illustrated in  FIGS. 1 and 2 , the column  200  comprises at least one peripheral wall  210  that delimits an internal volume  201  of the column  200 . More specifically, the peripheral wall  210  comprises at least one external face  211  and an internal face  212 , the internal face  212  more particularly delimiting this internal volume  201 . At least one heat and/or mass exchange means  230  is arranged in this internal volume  201 . Advantageously, a plurality of heat and/or mass exchange means  230  are arranged in the one same column  200 , each of these heat and/or mass exchange means  230  being housed in a compartment of the column  200 , this compartment being delimited, at least in part, by at least one distribution device. This distribution device—not illustrated here—is notably configured to ensure an even distribution of at least the first fluid, advantageously of the first fluid and the second fluid, over the one or more heat and/or mass exchange means. It is understood that this even distribution makes it possible to encourage the heat and/or mass exchanges that take place in these exchange means. Each compartment of the column  200  further comprises at least one retaining device  240  for retaining the heat and/or mass exchange means according to the invention, which is to say that this retaining device  240  forms a support, or contributes to forming a support, against which the heat and/or mass exchange means comes to bear. 
     According to the invention, the retaining device  240  according to the invention may be used to retain a heat and/or mass exchange means  230  inside any type of heat and/or mass exchange column  200 . The column  200  may thus, for example. be cylindrical, prismatic, or parallelepipedal. The heat and/or mass exchange means  230  may itself be formed of random packings, structured packings, for example of the cross-corrugated type, or else of beads. 
     Advantageously, the elements arranged in this column  200  are not fixed thereto, but it is possible for them to be so. 
     An example of a heat and/or mass exchange means  230  and the retaining device  240  against which it is arranged, will now be described in greater detail.  FIG. 1  illustrates one embodiment of the present invention, in which the heat and/or mass exchange column  200  comprises a retaining device  240  for retaining the heat and/or mass exchange means according to the invention, and  FIG. 2  for its part illustrates another embodiment of the present invention, in which the heat and/or mass exchange column  200  comprises two retaining devices  240  according to the invention. These  FIGS. 1 and 2  more particularly illustrate a vertical section through one of the compartments of the column  200 . 
       FIGS. 1 and 2  show, amongst other things, the external face  211  of the peripheral wall  210  of the column  200 , by virtue of which face the column is secured to other columns  200 , and the internal face  212  of this peripheral wall  210  which delimits, at least in part, the internal volume  201  of the column  200 . As previously mentioned, at least one heat and/or mass exchange means  230  and at least one retaining device  240  for retaining this heat and/or mass exchange means  230  are arranged inside this internal volume  201 . This at least one retaining means  240  is configured to position the exchange means  230  in the column  200  and notably to position it along the main extension axis X of the column  200 . Thus, as for example illustrated in  FIG. 1 , this at least one retaining device  240  needs to be arranged above the exchange means  230  when the apparatus to which the column  200  concerned belongs is in its functional position. According to the example illustrated in this  FIG. 1 , a support element  340  for supporting the heat and/or mass exchange means  230  is also arranged under this exchange means  230 . 
     This support element  340  may be selected from among all the currently known support elements  340  and here differs from the retaining device  240  according to the invention at least in that it needs to be fixed to the peripheral wall  210  of the column  200  in order for its position to be ensured. For example, this support element  340  may be welded or brazed to the peripheral wall  210  of the column  200 . Alternatively, this support element  340  may be formed as one with the internal face  211  of this peripheral wall  210  of the column  200 . The retaining device  240  according to the invention is described hereinbelow, with reference to  FIG. 2 , the references that refer to the same objects being identical across all the figures. 
     According to one particular application of the present invention, an air gas ascending in the column  200  may be distilled, for example in the exchange means  230 , to produce a nitrogen-enriched gas above the exchange means and an oxygen-enriched liquid below the exchange means. Liquid, from an external liquid inlet or from another exchange means arranged above the exchange means  230  illustrated falls down into the latter where an exchange of heat and/or of mass takes place with the air gas coming, for example, from an exchange means arranged below the exchange means  230  illustrated. The air gas may be air or nitrogen-enriched air if it comes from the exchange means arranged below the exchange means  230  illustrated. 
       FIG. 2  illustrates another embodiment of the present invention in which the column  200  comprises two retaining devices  240  according to the invention. As illustrated, these two retaining devices  240  for retaining the heat and/or mass exchange means  230  are arranged one on each side of this exchange means  230  along the main extension axis X of the column  200 . Advantageously, the use of two retaining devices  240  ensures the positioning of the heat and/or mass exchange means  230  along the main extension axis X of the column  200 , irrespective of the position of this column  200 . In other words, the position of this exchange means  230  along the main extension axis X of the column  200  is ensured whether the apparatus to which this column  200  belongs is in its operational position, or in any other position, for example a transport or assembly position. 
     Because these two retaining devices  240  are produced in accordance with the present invention, the description of one of them, given hereinafter, can be reapplied directly to the other. 
     Similarly, the retaining device  240  illustrated in  FIG. 1  is also identical to these two retaining devices  240  illustrated in  FIG. 2 , and the description of these two retaining devices  240  which will follow applies mutatis mutandis to the retaining device  240  illustrated in  FIG. 1 . In order not to overburden the figure, certain references are borne by only one of these retaining devices  240 , but it will be appreciated that these can be applied directly to the other one. 
     The retaining device  240  according to the present invention comprises at least two strips  241 . In order to be able to show certain features of the retaining device and of the strips of which it is composed, just one strip of the retaining device positioned under the heat and/or mass exchange means  230  in  FIG. 2  has been depicted, the other retaining devices  240  depicted in  FIGS. 1 and 2  being depicted with three strips at least partially visible. Chamfers  247  and the planar part of the two strips  241  that are perpendicular to the plane of the figure can be seen in the cutouts of the strip  241  in the plane of the figure. Each of these strips  241  extends in a main direction of extension D between two longitudinal ends  242 . As depicted in  FIGS. 1 and 2 , the two longitudinal ends  242  of at least one strip  241  are joined together by two transverse edges  244  and they are arranged bearing against the peripheral wall  210  of the column  200 , and more particularly against the internal face  212  of this peripheral wall  210 . In other words, at least one strip  241  of the retaining device  240 , and advantageously each strip  241  of this retaining device  240 , has at least two zones  250  of contact with the internal face  212  of the peripheral wall  210 . More specifically, the longitudinal ends  242  of at least one strip  241 , and advantageously the longitudinal ends  242  of each strip  241 , contribute to forming these contact zones  250 . 
     In order to make it easier to insert the strips  241 , and, therefore, the retaining device  240 , in the column  200 , the longitudinal ends  242  of the strips  241  each have at least one chamfer  247 . Advantageously, each longitudinal end  242  has two chamfers  247  connected by a ridge  248  which extends in a direction perpendicular to the main direction of extension D of the strip  241 , namely a direction parallel or substantially parallel to the internal face  212  of the peripheral wall  210  of the column  200 . 
     In that way, each strip  241  can easily be inserted into the heat and/or mass exchange column  200 , whatever the direction of this insertion. As illustrated, once the strip  241  has been inserted, the zones  250  of contact between this strip  241  and the internal face  212  of the peripheral wall  210  are formed, on the one hand, by a portion of said internal face  212  and, on the other hand, by one of the ridges  248  that connects the chamfers  247  of that strip  241 . 
     It may also be noted that the strip  241  comprises at least two cutouts  245 , distributed at the two longitudinal ends  242  of the strip  241 . In other words, each cutout  245  is formed closer to one of the longitudinal ends  242  than to a center  246  of this strip  241 . In other words, a first distance d 1  measured between one of the cutouts  245  concerned and the longitudinal end  242  of the strip  241  that is closest to this cutout  245  is less than a second distance d 2  measured between the cutout and the center  246  of the strip  241 , namely a point equidistant from the two longitudinal ends  242  of the strip  241 , this first distance d 1  and this second distance d 2  being measured parallel to the main direction of extension D of the strip  241 . These cutouts  245  confer elasticity on the strip  241 , allowing it to deform. In other words, these cutouts  245  are configured to allow an adjustment of a dimension of elongation of the strip  241 , in the main direction of extension D of this strip. 
     As depicted, each cutout  245  extends perpendicular to the main direction of extension D of the strip  241 , from one of the transverse edges  244  of this strip  241 . According to the example illustrated in  FIGS. 1 and 2 , the two cutouts  245  of the one same strip  241  extend from the same transverse edge  244  of the strip  241 . Alternatively, each cutout  245  may be formed from an opposite transverse edge  244  to the transverse edge  244  from which the other cutout  245  is formed. In other words, according to this alternative, the two cutouts  245  are arranged top to tail. As will be detailed more fully hereinafter with reference to  FIGS. 3 and 4 , each strip  241  may comprise at least four cutouts. 
     At least one strip  241 , advantageously all the strips  241  of the retaining device  240 , has a longitudinal dimension, namely one measured between its two longitudinal ends  242  parallel to its main direction of extension  0 , that is greater than a cross section of the column  200  in which it is arranged, this cross section of the column  200  being measured between two opposing points on the internal face  212  of the peripheral wall  210  thereof, parallel to a direction perpendicular to the main extension axis X of the column  200 . The result of this is that, by virtue of the cutouts  245  formed in this strip  241 , the latter deforms when it is introduced into the column  200 . More particularly, the longitudinal dimension of the strip  241  is reduced as it is inserted into the column  200 . 
     Once inside the column  200 , this strip  241  tends to revert to its original longitudinal dimension, thus applying a force F against the internal face  212  of the peripheral wall  210 , and more specifically in the zone  250  of contact formed between the internal face  212  of the peripheral wall  210  and the longitudinal ends  242  of the strip  241 . 
     Thus, each strip  241  of which the longitudinal ends  242  are bearing against the internal face  212  of the peripheral wall  210  generate two forces F that are parallel and in opposite directions which ensure mechanical retention of the strip  241  concerned, and therefore of the retaining device  240  that comprises this strip  241 , It will therefore be appreciated that it is these forces F that provide the mechanical retention of the retaining device  240  in the internal volume  201  of the column  200 . It will therefore be appreciated that the strips  241  illustrated in  FIGS. 1 and 2  in position in the column  200  are deformed, in the sense of a reduction in their longitudinal dimension. This reduction in their longitudinal dimension is, however, imperceivable to the naked eye, 
     According to the example illustrated here, the strip  241  comprises two slots  243 . As was specified previously, in  FIG. 2 , two of the strips  241  of the retaining device  240  arranged under the exchange means  230  have not been depicted, in order to render these slots  243  visible. Advantageously, all the slots  243  are identical and the description of one of them, which will follow, applies mutatis mutandis to the others. 
     These slots  243  are configured to accept another strip  241  that makes up the retaining device  240  in question. Each of these slots  243  extends from one transverse edge  244  of the strip  241  concerned and extends in a direction perpendicular to the main direction of extension D of said strip  241  and as far as substantially halfway along the height of the strip  241  which is to say the dimension of the strip between the two transverse edges. Thus, each slot  243  has an open end which opens onto one of the transverse edges  244  of the strip  241  and which allows the insertion of another strip  241 , and each slot  243  also has a closed end which acts as an end stop for the insertion of this other strip  241 , midway along the height of this strip  241 . 
     It may also be noted that, according to the example illustrated here, each slot  243  extends from the transverse edge  244  from which the cutouts  245  formed as close as possible to the longitudinal ends  242  of said strip  241  also extend. 
     It must be appreciated that this is merely one embodiment of the present invention and that the strip  241  could comprise a single slot  243 , in the case of a retaining device  240  comprising just two strips  241  as for example illustrated in FIG.  3 . Alternatively, the strip  241  could comprise more than two slots  243 , there being no maximum number of slots  243  defined. According to the example illustrated in  FIG. 2 , these slots  243  artificially divide the strip  241  into three portions of equivalent lengths, these lengths being measured parallel to the main direction of extension D of the strip  241 . 
     As previously mentioned, the retaining device  240  according to the invention acts as a support for the heat and/or mass exchange means  230 , which is to say that this heat and/or mass exchange means  230  bears against this retaining device  240 . More specifically, one transverse edge  244  of at least two strips  241  of the retaining device  240 , advantageously one transverse edge  244  of each strip  241  of the retaining device  240 , extends in a plane P against which the exchange means  230  bears. According to the invention, this plane P forms a planar bearing surface for the heat and/or mass exchange means  230 . Optionally, a mesh structure  260  may be arranged between the exchange means  230  and the retaining device(s)  240 . This mesh structure  260  notably reduces the risks of the exchange means  230 , or part of this exchange means  230 , passing through the retaining device  240 . In other words, this retaining device  240  has openings - which will be described more fully hereinafter with reference to  FIGS. 3 and 4 —of which a cross section is greater than a cross section of the mesh cells of the mesh structure  260 . According to the example illustrated here, two mesh structures  260  are arranged in the internal volume  201  of the column  200 , respectively between the heat and/or mass exchange means  230  and one of the two retaining devices  240  arranged in this column  200 . It will be appreciated that this is merely one embodiment and that provision could be made for the column  200  to comprise just one mesh structure  260  or else for it to be completely devoid of such a structure. 
     According to the invention, the mesh structure  260  and/or the strips  241  of the retaining device  240  comprise mass of which the melting point is higher than the maximum operating or manufacturing temperature of the column. 
     Thus, at least the mesh structure  260  and/or the strips  241  of the retaining device  240  are made for example of stainless steel, which has a melting point higher than 1000° C. 
     Advantageously, that makes it possible to avoid any deformation or deterioration of the mesh structure  260  and/or of the retaining device  240  during the course of operating and/or manufacturing the heat and/or mass exchange column for which they are intended. 
     The heat exchange means  230  may also be made of stainless steel. In any event, this heat exchange means  230  will be made from mass of which the melting point is higher than 500° C., for the reasons mentioned hereinabove. This heat exchange means  230  may for example comprise random packings, such as beads and/or spirals and/or rings, and/or structured packings, for example, corrugated or flat sheets extending predominantly in a direction parallel to the main extension axis X of the column. Whatever it might be, the exchange means  230  enables an increase in an area of contact, and therefore of heat and/or mass exchange, between the first fluid and the second fluid which are circulating in the column  200 . 
     The retaining device  240  according to the invention will now be described in greater detail with reference to  FIGS. 3 and 4 .  FIG. 3  is a view, in perspective, of the retaining device  240  according to a first embodiment of the present invention, and  FIG. 4  is a view, in perspective, of the retaining device  240  according to a second embodiment of the present invention. The features that are common to the first and second embodiments will be described first of all before the features specific to each embodiment are then described more fully. As previously mentioned, the strips  241  of a retaining device  240  according to the invention are identical, which means that the references borne by one of them can be reapplied directly to the others. 
     As previously mentioned, the retaining device  240  according to the invention comprises at least two strips  241  which have at least the features described hereinabove, with reference to  FIG. 2 . As illustrated, these strips  241  intersect, thus generating at least four openings  249  between the peripheral wall of the column across which the retaining device  240  is intended to be positioned, and the regions of contact that the longitudinal ends  242  of these strips  241 , and more particularly the ridges  248  of these longitudinal ends  242 , contribute to forming. 
     According to the embodiments illustrated in  FIGS. 3 and 4 , each strip  241  comprises at least four cutouts  245  distributed in pairs near each longitudinal end  242  of the strip  241  concerned. As previously mentioned, what is meant by “near” is that these cutouts  245  are formed closer to the corresponding longitudinal end  242  of the strip  241  than to the center of that strip  241 . According to the invention, the two cutouts  245  of the one same pair of cutouts  245  are formed from two opposite transverse edges  244  of the strip  241  concerned. In other words, the two cutouts  245  of the one same pair of cutouts  245  are formed top to tail. It will also be noted that, for a one same strip  241 , the two cutouts  245  formed closest to each longitudinal end  242  are formed from the same transverse edge  244  the strip  241 . Furthermore, the cutouts  245  of two strips  241  fitted one in the other by virtue of the slots  243  are formed as mirror images. In other words, between two strips  241  that collaborate via their slots  243  a reversal of the cutouts  245  with respect to the transverse edges  244  from which they extend can be observed. 
     Advantageously, it will be appreciated that the top to tail arrangement of the cutouts  245  ensures that the strip  241  deforms in the desired direction when inserted into the column, namely that this strip  241  deforms in the direction of a reduction in its length. In other words, this then ensures that the strip  241  deforms in a direction that brings its longitudinal ends  242  closer together. In addition, the manufacture of the strips  241  can thus be standardized, which means that the costs of manufacturing a retaining device  240  according to the invention are lower. 
     As mentioned hereinabove, one transverse edge  244  of at least two strips  241 , advantageously one transverse edge  244  of each strip  241  contributes to defining the plane P against which the heat and/or mass exchange means  230  bears, which is to say that at least two strips  241  have a transverse edge  244  contributing to forming the bearing surface of the exchange means  230 . It will be appreciated that, in the event that the mesh structure  260  is interposed between the exchange means  230  and the retaining device  240 , it is this mesh structure  260  that rests against this bearing surface, the exchange means  230  for its part resting against this mesh structure  260 . 
     According to the first embodiment illustrated in  FIG. 3 , the retaining device  240  according to the invention comprises two strips  241  which intersect substantially at their centers. In other words, each of these two strips  241  comprises a slot formed from one of its transverse edges  244  as described hereinabove, and extending toward the other transverse edge  244 , passing via the center of this strip  241 . As depicted, the retaining device  240  according to this first embodiment of the present invention adopts the shape of an X, and more specifically a cross shape. It will be appreciated that four openings  249  are thus generated between these strips  241  and the internal face  212  of the peripheral wall  210  of the column  200 . 
     According to the second embodiment illustrated in  FIG. 4 , the retaining device  240  according to the invention comprises four strips  241  which are arranged as a lattice. More specifically, these four strips  241  are, according to this second embodiment, parallel in pairs. In other words, the main extension directions of these strips are mutually parallel, in pairs. Thus, two of these strips  241  extend mainly in a first direction D 1 , the other two strips  241  extend in a second direction D 2 , the first direction D 1  being perpendicular to the second direction D 2 . As illustrated in  FIG. 3 , the main extension directions of two first strips  241   a  are parallel to the first direction D 1 , and the main extension directions of two second strips  241   b  are, for their part, parallel to the second direction D 2 . The result of this is that, in addition to the eight openings  249  created between the strips  241  and the internal face of the peripheral wall of the column for which the retaining device  240  in question is intended, a ninth opening  249  is generated between these four strips  241 , According to the second example illustrated here, this ninth opening  249  is square, which is to say that the strips  241  form a square grid pattern. 
     It must be appreciated that these are merely two exemplary embodiments of the present invention and that the retaining device  240  according to the present invention could comprise more strips  241  than have just been described. For example, on the basis of the second embodiment, it would be possible to anticipate a third embodiment, not illustrated here, in which three strips extend in the first direction, three slots then being formed in each of the strips which extend parallel to the second direction, each of these slots being intended to accept one of the strips that extend in the first direction. In other words, thy dimensions of the retaining device can easily be adapted to suit different columns, namely columns the dimensions of which vary, and more particularly, columns with different cross sections. However, the preference will be for square or circular columns in which the strips that make up the retaining device according to the invention are all identical, so that the manufacture thereof can be standardized, thus allowing a reduction in these production costs. 
     The present invention thus proposes a means that is simple, inexpensive and requires no assembly operation for maintaining the vertical position of a heat and/or mass exchange means in a heat and/or mass exchange column, which is to say for maintaining the position of this exchange means along a main extension axis of this column, regardless of the position of this column, 
     The present invention is not, however, limited to the means and configurations described and illustrated here, and it also extends to any equivalent means and configuration and to any technically effective combination of such means. In particular, the shape and the arrangement of the strips that make up the retaining device according to the invention can be modified without being detrimental to the invention, as long as they meet the functionalities described and illustrated in the present document.