FR2588194A1 - INCLINE ADSORBENT BED ADSORBER FOR TREATING GASEOUS MIXTURES - Google Patents

Abstract

THE INVENTION RELATES TO AN ABSORBER WITH AN INCLINED ADSORBING BED FOR TREATING GAS MIXTURES. THE ADSORBOR 2 INCLUDES, BETWEEN A LOWER SUPPORT GRID 8 AND A UPPER GRID 14, A SPACE 12 EMPLOYED BY ADSORBENT PARTICLES INTRODUCED BY ORIFICES 18. THE CONTAINER 2 HAS ORIFICES 24; 26 FOR GAS THAT CAN CROSS BED 12. GRID 8 INCLUDES A NON-HORIZONTAL, AND TYPICALLY INCLINED, SUPPORT SURFACE 10, FORMING WITH THE HORIZONTAL AN ANGLE THETA GREATER THAN THE NATURAL SLOPE ANGLE BY AT LEAST PART OF THE ADSORBENT PARTICLES. ANY INEQUALITY OF THE UPPER SURFACE OF BED 12 APPEARING IN USE IS THUS CONFINED TO THE PART OF THE BED SUPPORTED BY THE UPPER END OF THE GRILLE 8. APPLICATION: EXTRACTION OF WATER VAPOR AND CARBON GAS FROM THE AIR.

Description

The present invention relates to adsorbers.

  In particular, the invention relates to the kind of adsorber comprising a bed of adsorbent particles and for purifying or separating gaseous mixtures. It is important, in the operation of such adsorbers, to have a uniform depth of adsorbent particles at the gas front, due to

  the tendency of a gas to follow the path of less resistance

  flow. If a portion of the bed has a depth less than that of an adjacent section, there tends to be a greater flow of gas passing through the section with shallower section. So, the shallower section section loads faster in the or

  the constituents to be adsorbed in the gaseous mixture. The father

  the period during which the adsorber can be operated without regenerating it is thus reduced, since the

  section with a shallower section will allow the

  of the gaseous mixture that is to be adsorbed to pass through the top of this section before

  the deepest part is fully loaded.

  Traditionally, adsorbers have included adsorbent beds in the form of columns. Since the height of the column is large compared to its diameter, the problems associated with non-uniform operation of

  the adsorber are reduced to a minimum.

  More recently, attempts have been made to use relatively shallow beds of adsorbents, for example for the preliminary purification of air before the separation of its constituents in one or more distillation columns. The preliminary purification treatment includes the adsorption of water vapor and carbon dioxide, thus removed from the incoming air. Such adsorbers comprise a container having a bottom elongate support plate or grid for the bed, a complementary top plate or gate, and typically an inlet, through the top plate and through which the adsorbent particles are to be introduced into the bed. space between the upper and lower plates to form the beds. The lower plate is fixed. The top plate can be fixed or it can "float" and can be assembled after forming the bed. Both plates have passages for the gas, making it possible to achieve a uniform distribution of the

  gaseous mixture. Typically, gas spaces are deli-

  placed in the container above the top plate and below the bottom plate to facilitate the distribution of the gas. In normal operation, sedimentation of the sieve may occur. Similarly, a malfunction of the adsorber can disturb the sieve. In either case, large voids may occur and the bed surface may become uneven in an unpredictable manner. This difficulty appears, that the

  plate or top grid is fixed or floating.

  A proposal to overcome this difficulty consists in equipping the adsorber with a remote-controlled rake and

  to abandon the plate or upper support grid.

  However, such an expedient greatly increases the mechanical complexity and capital investment for the adsorber, particularly when the adsorber is needed for a large air treatment plant for the

  purify and / or then separate the constituents.

  The present invention therefore aims, in particular, at providing

  an adsorber which overcomes, or reduces to a minimum, the aforementioned difficulties associated with known adsorbers

described above.

  According to the present invention, this provides an adsorber containing a bed of adsorbent particles and comprising a container containing a first member having a support surface of the adsorbent particles.

  and to which is also associated a distribution device

  gas, a second complementary element which is associated with a gas distribution device and which cooperates with the first element to delimit the volume occupied by the bed, and at least one filling orifice located generally at the level of the particles most of the bed, said support surface forming with the horizontal an angle greater than the natural angle of repose of at least a portion (and preferably of the

  most or all of the adsorbent particles.

  Typically, the support surface is inclined, but it can also be vertical. The support surface is desirably elongated, the container

  typically having a general cylinder shape.

  The first and second elements are preferably grids or plates of the conventional type which are used in known adsorbers. These grids or plates can be pierced with evenly spaced passages for the gas or gases. The passages for the gas or gases may be of the conventional type, for example of the V-notch type.

  The adsorbers according to the invention are particularly suitable

  well suited for removing water vapor and / or carbon dioxide (carbon dioxide) from a mixture

gaseous such as air.

  In the adsorber according to the invention, a parallel plan

  laces to the lower support surface1 and which cuts the bed into two equal parts (bisecting plane), can contain the axis

longitudinal of the container.

  The container may have internal walls

  and external and / or be contained within an outer wall.

  An adsorber according to the invention will now be

  described by way of illustration and in no way as a limitation,

  Reference to the accompanying drawings, in which: Figure 1 is a schematic vertical section of the adsorber;

  Figure 2 is a longitudinal or trans-

  schematic side of the adsorber shown in Figure 1; and FIG. 3 is a schematic plan view of the upper terminal region of the lower grid.

  supporting the adsorber shown in Figures 1 and 2.

  With reference to the drawings, it can be seen that the adsorber is or comprises a container 2 of generally cylindrical shape

  having curved ends 4 and 6.

  Fixed within the container 2, a lower grid 8 defines an inclined floor 10, which supports a bed 12 of adsorbent particles. The grid 8 has a lower end 9 and an upper end 11 and is provided with passages (not shown) uniformly distributed to let the gas pass. The passages for

  the gas can be of any conventional kind.

  The interior of the container 2 is also covered

  of an upper grid 14 which, for all the important aspects

  tants, is identical to the grid 8. The upper grid 14 is fixed, and it extends parallel to the grid

  8 having the same angle of inclination as this grid 8.

  FIG. 1 shows the diameter 16 which extends parallel to

  same as the lower grid 8 and the upper grid

  14. The two grids are equidistant from this diameter 16.

  The plane of this diameter 16 contains the longitudinal axis A of the container 2. The diameter 16 and the surfaces of the grids 8 and 14 in contact with the adsorbent particles form with the horizontal a theta angle. This theta angle is greater than the natural slope angle of at least a portion of the adsorbent particles. This theta angle can be determined by simple experimentation. Different adsorbent particles can typically tend to

  present a range of different angles of natural slope.

  The theta angle is advantageously chosen so that it is greater than the largest angle of natural slope that

  it is found among the adsorbent particles.

  The container 2 comprises at least one and preferably

  a row of orifices 18, equally spaced, to fill

  wise to allow to introduce into the adsorber of

  adsorbent charge particles. The most important part

  top of the inner end surface of each orifice

  18 is juxtaposed to the upper part of the inferior surface

  grid 14 so that when the adsorber is loaded with adsorbent particles, some of these particles enter the space between the grids 8 and 14 at the highest possible level. To facilitate the flow of the adsorbent particles into the adsorber during the loading thereof, the axis of each orifice 18 is with the horizontal an angle greater than the aforesaid theta angle. The introduction of the particles is continued until there are no more adsorbent particles flowing freely in the bed. The space between the adjacent filling orifices 18 is chosen so as to keep to a minimum any possible dead space

  between the holes. We can easily calculate, by knowing

  the spacing of the orifices and the maximum natural slope angle of the adsorbent particle, the maximum value of any dead space of this type away from the end wall of the adsorber. So grid 8 has

  preferably a strip 32 without passages 34 passing through

  for the gases (see FIG. 3) said band having a predetermined width and extending from one side to the other of the grid 8 close to the wall of the container 2. Desirably, the upper grid 14 comprises a band complementary without through passages for gases. Each orifice 18 is provided with removable closure or closing members 19, which preferably close off

  fluid-tight manner when the orifices 18 are closed.

  After introduction of the adsorbent particles into the adsorbent

  To form the load, the orifices 18 are closed. Preferably, when they are closed, the orifices

  contain some adsorbent particles.

  If desired, the adsorber 2 may comprise at least one orifice, and preferably a row of equally spaced or equidistant discharge ports, at the lower level of the bed 12 to allow removal of the adsorbent from the adsorbent. adsorber if exhausted adsorbent particles have to be removed and replaced with a fresh charge of adsorbent particles. The orifices 20 comprise removable closure members 22 which, preferably, close off in a gastight manner when the orifices 20 are closed, that is to say during normal operation.

of the adsorber.

  The container 2 of the adsorber comprises, in its lower region, at least one orifice and preferably a row of orifices 24 equidistant for the flow of a gas. The axis of each orifice 24 is perpendicular to the lower grid 8 so as to facilitate the creation of a uniform flow of gas in the bed 12. There is at least one orifice, and preferably a similar row of orifices 26 equidistant for the flow of gas to the upper region of the container 2 of the adsorber. The axis of each orifice 26 is perpendicular to the upper grid 14. It exists between the orifices 24 and the

  grid 8 a chamber 28 and, between the grid 14 and the ori-

  26, a chamber 30, to facilitate distribution

uniform gas.

  The adsorber container can be supported

  by a suitable support device (not shown).

  Once the 1it of the adsorber loaded adsorbent particles, any unevenness of the surface of the bed will be confined to the upper part of the bed. It is thus possible, as described above, to reduce or minimize the difficulties of gas distribution so that

  to avoid a significant "short-circuit" in the bed,

  the upper part of the grid 8 of a strip devoid of through passages for the gas. In addition, any redistribution of the bed particles during the operation of the adsorber will be manifested by the creation of an inequality of the upper surface of the bed only in the region of the bed supported by the upper end 11 of the grate 8. because at this end a suitable surface of the gate is free of gas passages, it is still possible to prevent a significant "short circuit" of the gas flow in the bed. In addition,

  by arranging for the filling holes to contain

  With some excess adsorbent, it is possible to fill to a certain extent voids voids likely to be created at the upper end of the bed due to a possible deposit of sedimentation of the particles in the bed. In another embodiment of an adsorber

  according to the invention, the container of the adsorber can

  ter the inner and outer walls. Such an arrangement facilitates the loading of adsorbent particles into

  the adsorber, because the inner wall may have, at the

  upper bed, for example a suitable inclined surface (forming with the horizontal an angle greater than the natural slope angle of the adsorbent particles) and the particles can flow along the surface

  of such an end wall during filling of the bed.

  The theta angle can typically be 40.

  It is possible to increase the angle of inclination and it is possible to use an adsorber in which the grids 8

  and 14 were shot, in relation to their position

  in FIG. 1, in the counterclockwise direction. Of course, it is possible that the support surface is vertical. In this case, the longitudinal axis of the adsorber vessel may itself be vertical and there may be a single filling port just above the top of the adsorbent particles. Even for theta angle values greater than 45, up to 90, grid 8 still supports the bed (i.e. it adsorbs a

part of the load or weight).

  It goes without saying that, without departing from the scope of the invention,

  many changes can be made

  to the adsorber described and represents.

Claims (13)

  1. Adsorber containing a bed of particles   adsorbents, comprising a container (2) containing a first   first element (8) having a surface (10) for supporting the adsorbent particles (12), to which is associated a gas distribution device, a second element (14) complementary which is associated with a gas distribution device and which cooperates with the first element (8) for delimiting the volume of the bed (12) and at least one filling orifice (18) situated generally at the level of the upper particles of the bed, said adsorber characterized in that said support surface forms with the horizontal an angle (theta) greater than the natural angle of repose of at   at least a portion of the adsorbent particles.   2. Adsorber according to claim 1, characterized   in that the support surface (10) is elongated.   An adsorber according to claim 1 or claim   2, characterized in that the support surface is vertical.   An adsorber according to claim 1 or claim   2, characterized in that the surface (10) of port is tilted.   5. Adsorber according to claim 4, characterized in that the orifice (8), or each opening, filling forms with the horizontal an angle greater than the angle tilt on the horizontal.   6. Adsorber according to any one of the claims   prior art, characterized in that the elements (8 and 14) are grids or plates pierced with passages (34).   evenly spaced for gases.   An adsorber according to claim 5 or claim   dication 6, characterized in that each grid or plate (8; 14) has along its upper end a strip (32) devoid of through passages (34) for gases.   8. Adsorber according to any one of the claims   tions, characterized in that it comprises at least   a gas flow orifice (24) in the lower region   container (2), communicating with a chamber (28) of this container between this orifice (24) and the first element (14), and in that there is at least one orifice (26) for the flow of gas in the upper region of the container (2) communicating with a chamber (30) of this container   between the orifice (26) and the element (14).   9. Adsorber according to claim 8, characterized in that a plane parallel to the surface (10) support, and cutting the bed in two (bisecting plane) contains the axis longitudinal (A) of the container (2).   An adsorber according to claim 8 or claim   9, characterized in that the axes of the gas flow openings (24; 26) are perpendicular to the support surface (10).   11. Adsorber according to any one of the claims   the above, characterized in that it further comprises at least one discharge port (20) at the   bottom of the bed, for the discharge of the spent adsorbent. M   12. Adsorber according to any one of the   preceding statements, characterized in that the natural slope angle of all the adsorbent particles   is less than the angle (theta) that the surface (10) of sup- port made with the horizontal.   13. Adsorber according to any one of the claims   1 to 6, characterized in that the container (2) comprises internal and external walls.