System and method for homogeneous and dense filling of an adsorbent bed

Abstract

A vertical adsorbent bed filling system (1) comprises: - a reservoir (4) configured to contain the adsorbent, - a plurality of flexible tubes (6) arranged to connect the reservoir (4) to a plurality of filling holes (7) located at the top of the bed (1), - a rotating device associated with each flexible tube (6), positioned at the end of the tube, said end being configured to be inserted into a respective filling hole (7), - each rotating device being configured to disperse the adsorbent as a homogeneous spray over the surface of the bed (1). Illustration: Fig. 1

Description

Title of the invention: System and method for homogeneous and dense filling of an adsorbent bed

[0001] The invention relates to an adsorber for the pre-purification of a gas mixture before separation in a downstream unit. It finds a particular application in an adsorber of a TSA unit upstream of a cryogenic air separation unit.

[0002] Filling vertical adsorbent beds, particularly in the field of gas separation, presents challenges in terms of homogeneity and density. Current methods, often based on hole-by-hole filling, can lead to segregation of the adsorbent beads. This segregation creates areas of underflow and overflow, impairing bed performance during the adsorption and regeneration phases.

[0003] The invention aims to solve the problem of adsorbent bead segregation during the filling of a vertical bed, in order to improve the efficiency and performance of adsorption processes.

[0004] The invention proposes a filling system and method that make it possible to obtain a homogeneous and dense adsorbent bed. This is achieved through the use of several filling holes and associated rotating devices. These rotating devices, operating in parallel, create a homogeneous "rain" of adsorbent over the entire surface of the bed, thus minimizing segregation.

[0005] The invention relates to a system for filling a vertical adsorbent bed, comprising: - a reservoir containing the adsorbent, - a plurality of flexible pipes arranged to connect the reservoir to a plurality of filling holes located at the top of the bed, - a rotating device associated with each flexible hose, positioned at the end of the hose in question, said end being configured to be inserted into a respective filling hole, - each rotating device being configured to disperse the adsorbent in the form of a homogeneous rain over the surface of the bed.

[0006] The bed can be radial or parallelepiped in shape.

[0007] [Fig.1] Fig.1 is a cross-sectional view of an adsorbent bed;

[0008] [Fig.2] Fig.2 is a view unfolded along the perimeter for a radial bed or a front view for a parallelepiped bed;

[0009] [Fig. 3] Fig. 3 is an overview of the filling system, including the tank, flexible pipes, and rotating devices; and

[0010] [Fig.4] [Fig.4] is a cross-sectional view of the bed at the end of filling, showing the area active and inactive areas filled homogeneously.

[0011] The invention applies to a bed 1 which has an active zone 15 and an inactive zone 16 separated by a deflector 2, of radial shape, for example as described in FR-2741823 or to parallelepiped-shaped beds 1 as described in W02020 / 16990. The inactive zone serves as an adsorbent reservoir to compensate for any possible settling during operation.

[0012] The adsorber 3 may have two beds (not shown), for example, an activated alumina bed and a molecular sieve bed. It can, in particular, be used in the upstream purification stage of an air separation unit.

[0013] The description here is given with three filling holes and is easily extrapolated to any adsorber having at least two filling holes. Similarly, it is described with an adsorber 3 that contains one bed 1 of adsorbent, but is also easily extrapolated to any adsorber having more than one bed of adsorbent.

[0014] The adsorbent is placed in a hopper 4. A shut-off valve 5 can be placed in the lower part to start / stop the filling of the adsorber 3. In the lower part, three flexible pipes 6 (substantially vertical and in any case, with an angle with the horizontal much more subtly greater than the slope angle of the adsorbent to ensure a downward flow of the adsorbent) lead to the distribution holes 7 to a rotary distribution device.

[0015] The rotary distribution device consists of a vertical tube 9 with a drive motor 10 at its upper end and a distribution helix 11 at its lower end. The vertical tube 9 is traversed by the axis of rotation 12, around which the adsorbent beads circulate. The adsorbent beads are fed from the side of the tube 9, while maintaining an angle with respect to the horizontal that is significantly greater than the slope angle of the adsorbent to ensure downward flow of the adsorbent.

[0016] The distribution helix 11 can be a simple horizontal plate with a few vertical fins so as to project the adsorbent beads in all directions. Its diameter is typically in the range of 30 to 60 mm.

[0017] The rotational speed must be sufficient to properly project the adsorbent beads, but not so high as to limit bead attrition and dust generation. The speed is preferably between 500 RPM and 2000 RPM.

[0018] The free zone between the end of the vertical tube 9 and the helix 11 (or the helix plate 11) must allow the unrestricted passage of the beads. Its characteristic height is preferably between three and five times the characteristic dimension of the adsorbent beads.

[0019] Each rotary distribution device is placed in the upper part of the bed 1, but in such a way that the propeller 11 is placed under the deflector 2, in the active zone 15. The filling hole 7 is large enough to accommodate the rotating dispensing device. Similarly, the space between the deflector 2 and the grid 14 is sufficient to allow the end of the vertical tube 9 with the propeller 11 to pass through. The beads are sprayed in all directions, bouncing off the grids 14 and the walls. This also creates a dense and homogeneous bed 1 of adsorbent.

[0020] The diameter of the helix 11 is preferably between the external diameter and the internal diameter of the vertical tube 9. This makes it possible in particular not to make the helix 11 rub against the grid 14 or against a mesh pressed against the grid 14 to retain the adsorbent beads.

[0021] A valve can be placed in the upper part of the rotary distribution device, outside the adsorber, to regulate the flow rate during filling. This valve can be, for example, a guillotine, butterfly, or diaphragm type. A flow meter can also be installed.

[0022] During filling, all the filling holes 7 are therefore supplied simultaneously by a rotating distribution device. In the case of a parallelepiped bed, the flow rate supplying the holes in the left / right part near the side walls can be regulated differently from the central holes, in particular with a lower flow rate.

[0023] During filling, a level measurement of the bed 1 of adsorbent can be taken to check its relative flatness, the objective being to avoid creating bumps / hollows whose slope exceeds the angle of slope, avoiding any risk of segregation of the beads by rolling.

[0024] This measurement can be taken continuously during filling with a suitable device located in the active zone 15 of the bed, or by stopping the filling from time to time, typically every 10-20 minutes, through the filling holes 7 using a portable device, for example, a plumb line or a laser measuring device. The observed level deviations can then be corrected by adjusting the opening of each control valve or by adjusting the height of the free zone at each propeller 11.

[0025] When the active zone 15 located under the deflector 2 has been filled, the rotating distribution devices are moved so as to place the helix 11 just below the filling hole 7 to allow the dense and homogeneous filling of the inactive zone 16. A temporary cover can be placed over the filling hole 7 around the rotating distribution device to prevent adsorbent beads from being projected outwards from the adsorber 3.

[0026] The bed 1 is filled to the brim of the filling holes 7. Filling is preferably carried out in the workshop, and the adsorber 3 is transported thus filled. External lighting or lighting integrated into the rotary distribution device may be provided.

[0027] The adsorbent is preferably in the form of beads and may in particular be activated alumina, molecular sieve, silica gel, activated carbon.

[0028] The filling system operates by simultaneously feeding the adsorbent through all the filling holes 7. The rotating devices disperse the adsorbent uniformly, ensuring dense and homogeneous filling. Flow control devices and level measurements can be used to adjust the process and ensure the flatness of the bed 1.

[0029] The advantages of the invention are as follows: - Homogeneity: Homogeneous filling minimizes the segregation of adsorbent beads. - Density: Dense filling improves the efficiency of the adsorbent bed. - Performance: Improved homogeneity and density lead to better performance during the adsorption and regeneration phases. - Adaptability: The system can be adapted to different types of adsorbent beds and different adsorber configurations.

[0030] The proposed invention offers an effective solution to the problem of adsorbent bead segregation during the filling of vertical beds. The described system and filling method make it possible to obtain a homogeneous and dense adsorbent bed, thus improving the performance and efficiency of adsorption processes.

Claims

[Claim 1] Demands A vertical adsorbent bed filling system (1), comprising: - a reservoir (4) configured to contain the adsorbent, - a plurality of flexible conduits (6) arranged to connect the reservoir (4) to a plurality of filling holes (7) located at the top of the bed (1), - a rotating device associated with each flexible hose (6), positioned at the end of the hose in question, said end being configured to be inserted into a respective filling hole (7), - each rotating device being configured to disperse the adsorbent in the form of a homogeneous rain over the surface of the bed (1).

Images