Adsorbent with a hierarchical structure.

Abstract

Adsorbent agglomerate comprising an internal region (7) and a superposition of layers of adsorbent particles (1), the layers of adsorbent particles (1) succeeding one another from said internal region (7), enveloping said internal region (7), each of the adsorbent particles (1) having a volume called particle volume, at least two layers of adsorbent particles (1) constituting hierarchical layers (2, 3, 4, 5), said at least two layers being the layers of adsorbent particles (1) furthest from the internal region (7), adsorbent agglomerate in which the adsorbent particles (1) constituting each of the hierarchical layers (2, 3, 4) preceding a subsequent hierarchical layer (3, 4, 5) have an average particle volume less than the average particle volume of the adsorbent particles (1) constituting the subsequent hierarchical layer (3, 4, 5),a standard deviation of the particle volume values ​​of the adsorbent particles (1) of each of the hierarchical layers being less than 20%, preferably less than 10%, preferably less than 5%, relative to the average particle volume of the adsorbent particles (1) constituting said hierarchical layer. Abbreviated figure: Fig. 1,

Description

Title of the invention: Hierarchical structure adsorbent.

[0001] The invention belongs to the field of materials used to separate gaseous mixtures into a strongly adsorbable fraction and a weakly adsorbable fraction.

[0002] Adsorption is widely used to purify or separate (fractionate) gases. Examples include the fractionation of "n" and "iso" paraffins, the fractionation of xylenes and alcohols, the production of nitrogen or oxygen from atmospheric air, and the CO2 deballasting of combustion gases and blast furnace gases. On the purification side, applications include dryers, hydrogen and helium removal, methane-rich gas removal, and the adsorption of trace impurities from numerous fluids (mercury removal, NOx removal, sulfur compounds, etc.).

[0003] Increasing the efficiency and reducing the costs of adsorption separation processes requires improving the adsorbents used in such processes and reducing cycle times. The need for smaller mass transfer zones in rapid adsorption cycles necessitates the use of smaller adsorbent agglomerates or smaller non-agglomerated adsorbent crystals or solids. However, reducing the size of the adsorbents leads to increased pressure losses across the adsorbent bed and a risk of fluidization of said bed. Since smaller adsorbents are also more fragile, their deterioration is likely during handling or through fluidization.

[0004] It is therefore desirable to propose an adsorbent to overcome these known disadvantages of the prior art.

[0005] The invention therefore relates to an adsorbent agglomerate comprising an internal region and a superposition of layers of adsorbent particles, the layers of adsorbent particles succeeding one another from said internal region, enveloping said internal region, each of the adsorbent particles having a volume called particle volume, at least two layers of adsorbent particles constituting hierarchical layers with respect to each other, said at least two layers being the layers of adsorbent particles furthest from the internal region, adsorbent agglomerate in which the adsorbent particles constituting each of said hierarchical layers preceding a subsequent hierarchical layer have an average particle volume less than the average particle volume of the adsorbent particles constituting the following hierarchical layer,a standard deviation of the particle volume values ​​of the adsorbent particles of each of the hierarchical layers being less than 20%, preferably less than 10%, preferably less than 5%, relative to the average particle volume of the adsorbent particles constituting the hierarchical layer, considered.

[0006] According to one embodiment, the hierarchical layers are concentric. In particular, the internal region is a central region of the adsorbent agglomerate.

[0007] According to one embodiment, the adsorbent agglomerate comprises at least three hierarchical layers, preferably at least four hierarchical layers.

[0008] According to one embodiment, the adsorbent agglomerate comprises between two and fifteen hierarchical layers including boundaries, preferably between two and ten hierarchical layers including boundaries.

[0009] According to one embodiment, the thickness of each of the hierarchical layers is between 30 and 500 microns. In particular, the thickness of the hierarchical layer furthest from the internal region is between 30 and 300 microns. In particular, the thickness of the hierarchical layer preceding the next hierarchical layer furthest from the internal region is between 50 and 400 microns. In particular, the thickness of the hierarchical layer preceding the next hierarchical layer, which itself precedes the hierarchical layer furthest from the internal region, is between 100 and 500 microns.In particular, the hierarchical layer furthest from the internal region, the hierarchical layer preceding the next hierarchical layer furthest from the internal region, and the hierarchical layer preceding the next hierarchical layer which itself precedes the hierarchical layer furthest from the internal region have the same volume or substantially the same volume.

[0010] According to one embodiment, the ratio of the volume of each hierarchical layer following a preceding hierarchical layer to the volume of said preceding hierarchical layer is between 100% and 350%, preferably between 150% and 250%. In particular, the ratio of the volume of a hierarchical layer furthest from the internal region to the volume of a hierarchical layer preceding the next hierarchical layer furthest from the internal region is between 170% and 250%. In particular, the ratio of the volume of the hierarchical layer preceding the next hierarchical layer furthest from the internal region to the volume of a hierarchical layer preceding the next hierarchical layer that itself precedes the next hierarchical layer furthest from the internal region is between 190% and 220%.

[0011] According to one embodiment, the ratio of the volume of a hierarchical layer furthest from the internal region to the volume of the adsorbent agglomerate is between 20% and 90%, preferably between 35% and 75%, preferably between 45% and 65%.

[0012] The inter-particle spaces of the outermost hierarchical layer(s) covering the previous hierarchical layer(s) are advantageously wider than the inter-particle spaces of the previous hierarchical layer(s).

[0013] According to one embodiment, the hierarchical layers represent at least 30%, preferably at least 50%, preferably at least 60%, of all the layers of the adsorbent agglomerate. The average volume of the adsorbent particles increases continuously between the hierarchical layer closest to the inner region and the hierarchical layer furthest from the inner region. The hierarchical layer furthest from the inner region is not covered by any other layer of adsorbent particles.

[0014] According to one embodiment, the internal region comprises an aggregate of adsorbent particles. In particular, no hierarchical layering of adsorbent particles is present in the aggregate.

[0015] According to one embodiment, the adsorbent agglomerate is substantially spherical.

[0016] According to one embodiment, the particle volume of each of the particles ad The particle size of the adsorbents in the hierarchical layers is between 4 and 4000 microns, preferably between 40 and 400 microns. In particular, the particle size of each adsorbent particle in the hierarchical layer furthest from the inner region is between 200 and 4000 microns. Specifically, the particle size of each adsorbent particle in the hierarchical layer preceding the next hierarchical layer furthest from the inner region is between 60 and 1000 microns. In particular, the particle size of each adsorbent particle in the hierarchical layer preceding the next hierarchical layer, which itself precedes the next hierarchical layer furthest from the inner region, is between 30 and 500 microns.

[0017] According to one embodiment, the adsorbent particles are substantially spherical and the adsorbent particles constituting each of said hierarchical layers preceding a subsequent hierarchical layer have an average diameter less than the average diameter of the adsorbent particles constituting said subsequent hierarchical layer.

[0018] According to one embodiment, the adsorbent particles comprise one or more adsorbent crystals. In particular, the adsorbent particles comprise a plurality of adsorbent crystals agglomerated together. In a particular embodiment, each adsorbent particle within the hierarchical layers consists of a single adsorbent crystal. In this embodiment, the adsorbent crystals constituting each of said hierarchical layers preceding a subsequent hierarchical layer have a smaller average volume than the average volume of the adsorbent crystals constituting said subsequent hierarchical layer.

[0019] According to one embodiment, the adsorbent particles included in the hierarchical layers comprise one or more amorphous solid(s). In particular, the adsorbent particles comprise a plurality of agglomerated amorphous solids. The amorphous solids include, in particular, activated carbon, alumina, or other Metal oxides and / or silica, such as silica gel. In one particular embodiment, each adsorbent particle within the hierarchical layers consists of a single amorphous solid. In this embodiment, the amorphous solids constituting each of said hierarchical layers preceding a subsequent hierarchical layer have an average volume less than the average volume of the amorphous solids constituting said subsequent hierarchical layer.

[0020] According to one embodiment, the adsorbent particles comprise a binder, in particular between 1 and 12 percent by mass (wt%) of binder, preferably between 4 and 10 percent by mass of binder.

[0021] According to one embodiment, the adsorbent agglomerate comprises a binder between the adsorbent particles, in particular between 1 and 10 percent by mass (wt%) of binder.

[0022] According to one embodiment, the adsorbent agglomerate is a zeolite adsorbent, in particular a FAU zeolite, in particular a zeolite X, Y or A, especially one exchanged with calcium. Preferably, the adsorbent agglomerate is a zeolite of the LSX type.

[0023] According to one embodiment, the adsorbing agglomerate has a tortuosity between 1 and 2.2.

[0024] The invention also relates to an adsorber comprising an adsorbent bed, said bed comprising a plurality of adsorbent agglomerates as described above.

[0025] The invention also relates to a method for separating a gas mixture by adsorption, using an adsorbent agglomerate as described above or an adsorber as described above. The method is, in particular, a pressure-modulated adsorption (PSA) process, specifically a VSA or VPSA type process. The method can also be a Rapid PSA (RPSA) type pressure-modulated adsorption process, in which the pressure cycle time is typically less than one minute. The method is, in particular, a method for separating air, for example, for oxygen production.

[0026] The invention also relates to the use of the adsorbent agglomerate as described above or of an adsorber as described above in the processes of fractionation of "n" and "iso" paraffins, of fractionation of xylenes, of fractionation of alcohols, the processes of purification of hydrogen or helium.

[0027] The invention also relates to a method for manufacturing an adsorbent agglomerate, in particular as described above, comprising the following steps: - supplying a plurality of adsorbent particles, each of the adsorbent particles having a volume called particle volume, - constitution of at least two batches of adsorbent particles, each batch of adsorbent particles corresponding to a targeted average particle volume of the particles that constitute it, a standard deviation of the particle volume values ​​of the adsorbent particles of each batch being less than 20%, preferably less than 10%, preferably less than 5%, relative to the average targeted particle volume of said batch, - an agglomeration stage comprising the sub-stages: a) agglomeration of the adsorbent particles from a first batch into a first layer of adsorbent particles, b) agglomeration of the adsorbent particles from the next batch into a subsequent upper layer of adsorbent particles, covering the first layer of adsorbent particles, the average targeted particle volume of each of the batches preceding a subsequent batch being less than the average targeted particle volume of said subsequent batch.

[0028] According to one embodiment, step b) is repeated until the adsorbent particles of a final batch have agglomerated into a final layer of adsorbent particles covering the previous layer of adsorbent particles. The adsorbent agglomerate then comprises at least three layers of adsorbent particles.

[0029] According to one embodiment, the number of lots is between two and fifteen inclusive terminals, in particular between two and ten inclusive terminals.

[0030] According to one embodiment, the particle size of the supplied adsorbent particles is between 4 and 4000 microns³, preferably between 40 and 400 microns³. In particular, the particle size of the adsorbent particles in the first batch is between 4 and 10 microns³. In particular, the particle size of the adsorbent particles in the last batch is between 200 and 4000 microns³. In particular, the particle size of the adsorbent particles in the batch preceding the last batch is between 60 and 1000 microns³.

[0031] According to one embodiment, the process includes a step of supplying an aggregate of adsorbent particles, and the agglomeration (agglomeration step) of the adsorbent particles from the batches constituted is carried out on the aggregate. In particular, no hierarchical layering of adsorbent particles is present in the aggregate.

[0032] According to one embodiment, the batches are formed by sieving the adsorbent particles.

[0033] According to one embodiment, the process includes a step of feeding the adsorbent particles from the constituted batches to the agglomeration step, the feeding being done from reservoirs of adsorbent particles, each reservoir containing one of the constituted batches.

[0034] According to one embodiment, the agglomeration step is carried out in the presence of moisture or in a dry state.

[0035] According to one embodiment, the agglomeration step includes a substep of preparing each batch of adsorbent particles in the form of an adsorbent particle dispersion. The dispersion includes, in particular, a surfactant and a porous agent.

[0036] According to one embodiment, the agglomeration step is performed by fluidization. In particular, the agglomeration step comprises the following substeps: a') Fluidized bed spraying of a first prepared dispersion, corresponding to the first batch, until the adsorbent particles of the first dispersion agglomerate into a first layer of adsorbent particles, b') fluidized bed spraying of a subsequent prepared dispersion, corresponding to the next batch, until agglomeration of the adsorbent particles of the subsequent dispersion into a layer of subsequent adsorbent particles covering the first layer of adsorbent particles.

[0037] According to one embodiment, step b') is repeated until the adsorbent particles of a last dispersion, corresponding to the last batch, are included in agglomeration into a last layer of adsorbent particles covering the previous layer of adsorbent particles.

[0038] According to one embodiment, the fluidized bed agglomeration step is carried out in a reactor in which the prepared dispersions are fed with a spray, in particular at a pressure between 1 and 10 bar absolute. The pressure within the reactor is in particular between 1 and 10 bar absolute.

[0039] According to one embodiment, the fluidization is achieved by circulating a gaseous flow in the reactor, said gaseous flow being in particular at a temperature between 40 and 500°C.

[0040] Alternatively, the agglomeration step is performed by a rotating platform. In particular, the agglomeration step comprises the following sub-steps: a”) placing a first prepared dispersion, corresponding to the first batch, on a tray, and rotating said tray until the adsorptive particles of the first dispersion agglomerate into a first layer of adsorptive particles, al”) possibly transfer of the agglomerated adsorbent particles from said tray to another tray, b") arrangement on said tray or other tray of a subsequent prepared dispersion, corresponding to the next batch, and rotation of said tray or other tray until agglomeration of the adsorbent particles of the subsequent dispersion into a layer of subsequent adsorbent particles covering the first layer of adsorbent particles. All the dispersions can be agglomerated on the same plateau. Alternatively, the dispersions are agglomerated each on a different plateau. The agglomeration step then includes the transfer substep a1a).

[0041] According to one embodiment, step b”) and optionally step a1”) is repeated until the adsorbent particles of a last dispersion, corresponding to the last batch, in a final layer covering the previous layer.

[0042] According to one embodiment, the process includes a discharge step and an activation step of the resulting adsorbent agglomerate.

[0043] Fig. 1 represents an adsorbent agglomerate according to the invention; Figure [Fig. 2] represents a first embodiment of a manufacturing process for an adsorbent agglomerate; Figures 3 and 4 each represent a variant of a second embodiment of the manufacturing process.

[0044] An adsorbent agglomerate comprises an internal region 7 and a superposition of layers of adsorbent particles 1, the layers of adsorbent particles succeeding one another from said internal region 7, enveloping said internal region 7, each of the adsorbent particles 1 having a volume called particle volume, at least two layers 2, 3, 4, 5 of adsorbent particles 1 constituting hierarchical layers, each of the hierarchical layers being made up of a set of adsorbent particles 1 having a target average particle volume, a standard deviation of the particle volume values ​​of the adsorbent particles 1 of each of the sets being less than 20%, preferably less than 10%, preferably less than 5% with respect to the target average particle volume of said set of adsorbent particles 1, said at least two layers 2, 3, 4, 5 being the layers furthest from the internal region 7,characterized in that in each of the hierarchical layers 2, 3, 4 covered by a subsequent hierarchical layer 3, 4, 5, the average targeted particle volume is less than the average targeted particle volume of the set of adsorbent particles 1 constituting the subsequent hierarchical layer 3, 4, 5.

[0045] The adsorbent agglomerate according to the invention comprises substantially spherical adsorbent particles 1 arranged in layers and an internal region 7, here a central region of the adsorbent agglomerate. In the embodiment of [Fig. 1], a layer 2 of adsorbent particles is covered by an upper layer 3 covering the lower layer 2, itself covered by an upper layer 4 covering the lower layer 3, itself covered by an upper layer 5 covering the lower layer 4. Layers 2, 3, 4, and 5 are located away from the internal region 7 and are the layers furthest from the internal region 7. Layer 5 is the layer furthest from the internal region 7 or the outermost layer of the adsorbent agglomerate. Layers 2, 3, 4, and 5 enclose the internal region 7.Layers 2, 3, 4 and 5 follow one another starting from the said internal region 7, that is to say that, in the direction going from the internal region towards an external surface of the adsorbing agglomerate, layer 2 precedes layer 3, which precedes layer 4 which itself precedes layer 5 which is furthest from the internal region 7. . In other words, layer 5 follows layer 4, which itself follows layer 3, which itself follows layer 2.

[0046] In the context of the invention, a layer which immediately precedes another is called a "previous layer" and a layer which immediately follows another is called a "next layer".

[0047] The adsorbent agglomerate of [Fig. 1] thus comprises a superposition of concentric layers 2, 3, 4, and 5 of adsorbent particles 1, each adsorbent particle 1 having a volume referred to as the particle volume. Each of the layers 2, 3, 4, and 5 corresponds to a target average particle volume of each of the adsorbent particles 1 contained therein, namely that the adsorbent particles 1 contained in one of the layers 2, 3, 4, and 5 each have a particle volume close to the target average particle volume, the particle volume being able to vary between the adsorbent particles 1 with a standard deviation of the particle volume values ​​of the particles 1 of said layer, a controlled standard deviation of less than 20%, preferably less than 10%, preferably less than 5%, with respect to the target average particle volume of said layer. The layer is thus defined by the volume of the adsorbent particles 1 that constitute it.The target average particle volume corresponds to the desired volume value for the design of a layer.

[0048] Layers 2, 3, 4 and 5 constitute so-called hierarchical layers. The hierarchical layers 2, 3, 4, 5 exhibit a hierarchy among themselves by obeying the following rule: the average targeted particle volume of the adsorbent particles 1 of a hierarchical layer 2, 3, 4, said lower, is strictly less than the average targeted particle volume of the adsorbent particles of the next hierarchical layer 3, 4, 5 succeeding the lower layer 2, 3, 4, the next hierarchical layer 3, 4, 5 covering said lower layer 2, 3, 4.

[0049] The average particle volume of a hierarchical layer is calculated by summing the volumes of all the adsorbent particles in the hierarchical layer, divided by the number of adsorbent particles in said hierarchical layer. The standard deviation of the particle volumes of the particles in a hierarchical layer corresponds to the distribution of the particle volume values ​​of the particles in said hierarchical layer around the target average particle volume of said hierarchical layer.

[0050] In the embodiment of [Fig. 1], the internal region 7 consists of an aggregate of adsorbent particles arranged in layers without any particular hierarchy between them. Layers 2, 3, 4 and 5 are arranged around the aggregate, enveloping it.

[0051] The agglomeration of the adsorbent particles together is optionally done using a binder.

[0052] In the embodiment shown, the adsorbent particles 1 are formed from a powder of crystals, the powder being agglomerated to form said adsorbent particles. The agglomeration can also be achieved using a binder. In another embodiment not shown, the adsorbent particles are formed from a powder of amorphous solids, the powder being agglomerated to form said adsorbent particles. The amorphous solids can consist of activated carbon or silica gel. The agglomeration can again be achieved using a binder.

[0053] Adsorbent particles 1 comprising agglomerated crystals or amorphous solids are also, when substantially spherical, called adsorbent beads. The hierarchically porosity adsorbent agglomerate according to the invention then comprises an agglomeration of adsorbent beads arranged in concentric layers, each of said beads comprising an agglomeration of crystals or amorphous solids. In an embodiment where each adsorbent particle within the meaning of the invention consists of a single adsorbent crystal, the hierarchically porosity adsorbent agglomerate comprises an agglomeration of crystals arranged in layers. The layers are hierarchically ordered according to the following rule: the average targeted volume of crystals in a lower layer is less than the average targeted volume of crystals in the next layer, covering said lower layer.

[0054] The interparticle spaces 6 of the outermost layer(s) of the internal region 7, covering the lower layer(s), are advantageously wider than the interparticle spaces of the lower layer(s). The interparticle space measures the space between the adsorbent particles 1. The interparticle spaces of the outermost layers open, in particular, onto the pore network of the adsorbent particles, notably mesopores and micropores. Thus, the diffusion rate of molecules between the adsorbent particles of the outermost layers is optimized. Because the outermost layers generally represent the majority of the volume of the adsorbent agglomerate, mass transfer is greatly improved. In the case of concentric hierarchical layers, the mass transfer properties of the adsorbent are homogenized, thanks to the central symmetry of the geometry of the adsorbent agglomerate.The smaller particle volume of the lower layers allows for the highest adsorption rate characteristic of small adsorbent particles, and thus greater selectivity. Thanks to the large volume of the adsorbent agglomerate according to the invention, relative to the adsorbent particles 1 constituting it, the drawbacks arising from the use of these small adsorbent particles 1, known in the prior art, related to increased pressure losses and / or fluidization, are avoided. A compromise between seemingly irreconcilable properties is thus found.

[0055] The particle volume within the meaning of the invention corresponds to the macroscopic volume of an adsorbent particle 1 as it can be observed and measured under a microscope, that is to say, including the interstices between the constituent elements of said adsorbent particle, in particular the spaces between crystals or between amorphous solids. The volume of the adsorbent agglomerate within the meaning of the invention corresponds to the macroscopic volume of the adsorbent agglomerate, that is to say, including the interparticle spaces 6. The average volume of the adsorbent particles 1 of a lower layer is less than the average volume of the adsorbent particles 1 of the next layer, covering said lower layer. In other words, an average characteristic dimension of the adsorbent particles 1 of the lower layer is less than an average characteristic dimension of the adsorbent particles 1 of the next layer.

[0056] The adsorbent agglomerate according to the invention can be a zeolite adsorbent, in particular a FAU zeolite, and preferably a zeolite X. For example, zeolite X has a silica to alumina ratio of less than 1.15, preferably less than 1.1 or substantially equal to 1.0.

[0057] In the embodiment of [Fig. 1], the adsorbent is a calcium (Ca)-exchanged faujasite-type adsorbent, adapted for use after activation in an adsorbent bed of an adsorber for a pressure swing adsorption (PSA) separation process. However, the adsorbent agglomerate according to the invention can be used in any adsorption process, for example, a pressure swing adsorption (PSA) process, in particular a vacuum swing adsorption (VPSA) process. The process can also be a rapid PSA (RPSA) type pressure swing adsorption process, in which the pressure cycle time is typically less than one minute.

[0058] Fig. 2 is a schematic representation of an example of a manufacturing process by fluidized bed agglomeration of an adsorbent agglomerate with hierarchical porosity according to the invention.

[0059] A quantity of adsorbent particles 1 is supplied, and the adsorbent particles are distributed according to their particle volume, so as to constitute batches SI, S2, S3, ... Sn. The adsorbent particles 1 included in each of the batches SI, S2, S3, ... Sn all have a similar particle volume, close to a target average particle volume, which characterizes said batch. The standard deviation of the particle volume values ​​of the adsorbent particles 1 of each of the batches SI, S2, S3, ... Sn constituted is controlled so as to be less than 20%, or even less than 10%, or even less than 5% with respect to the target average particle volume. The remainder of the manufacturing process consists of agglomerating the adsorbent particles 1 thus distributed into batches in a hierarchical manner. The batches SI, S2, S3, ... Sn are classified in this order by increasing target average particle volume.

[0060] In the example of [Fig. 2], the batches SI, S2, S3, ... Sn are prepared as dispersions dl, d2, d3, ..., dn with a surfactant and a porogenic agent. The dispersions dl, d2, d3, dn thus prepared are then fed one after the other into a spraying device, for example a fluidizing tank or reactor, in which the dispersions dl, d2, d3, ..., dn are sprayed in a fluidized bed.

[0061] The first dispersion dl is sprayed in a fluidized bed for the time necessary for the adsorbent particles 1 contained in the first sprayed dispersion dl to agglomerate together, forming a first layer 2 of the adsorbent agglomerate. The agglomeration of the first layer 2 can be carried out on an aggregate. Then, the second dispersion d2 is in turn sprayed in a fluidized bed for the time necessary for the adsorbent particles 1 contained in the second dispersion d2 to agglomerate into a second layer 3, covering the first layer 2. This process is repeated until the particles of a final dispersion agglomerate into a final layer 5, covering the previous layer 4. The final layer 5 constitutes the outermost layer of the adsorbent agglomerate.An adsorbent agglomerate in concentric layers of adsorbent particles is thus obtained, in which the particle volume decreases constantly from the outer layer to the innermost layers.

[0062] Figure 3 is a schematic representation of another example of a method for manufacturing an adsorbent agglomerate with hierarchical porosity according to the invention, by agglomeration on a rotating plate. The method is similar to that of Figure 2, but differs in that the dispersions d1, d2, d3, ..., dn are fed, in the same order, successively one after the other, onto one or more rotating plates for agglomeration. The rotating plate(s) is / are rotated for the time necessary for the agglomeration of the particles of a given dispersion into a layer, possibly overlapping the previous layer. All batches SI, S2, S3, ... Sn can be agglomerated on a single rotating platform as in the example of [Fig.3], or each of the batches SI, S2, S3, ... Sn can be agglomerated on a different rotating platform (P_rotating 1, P_rotating 2, ... P_rotating n), as in the example of [Fig.4], with, where appropriate, a transfer step Al, A2 of the adsorbent particles 1 previously agglomerated on a given rotating plate to the next rotating plate.

Claims

Claims

1. Adsorbent agglomerate comprising an internal region (7) and a superposition of layers of adsorbent particles (1), the layers of adsorbent particles (1) succeeding one another starting from said internal region (7), enveloping said internal region (7), each of the adsorbent particles (1) having a volume called particle volume, at least two layers of adsorbent particles (1) constituting hierarchical layers between them (2, 3, 4, 5), said at least two layers being the layers of adsorbent particles (1) furthest from the internal region (7), adsorbent agglomerate in which the adsorbent particles (1) constituting each of said hierarchical layers (2, 3, 4) preceding a following hierarchical layer (3, 4, 5) having an average particle volume less than the average particle volume of the adsorbent particles (1) constituting said following hierarchical layer (3, 4, 5),a standard deviation of the particle volume values ​​of the adsorbent particles (1) of each of the hierarchical layers being less than 20%, preferably less than 10%, preferably less than 5% relative to the average particle volume of the adsorbent particles (1) constituting said hierarchical layer.,

2. Adsorbent agglomerate according to the preceding claim, in which the hierarchical layers (2, 3, 4, 5) are concentric.

3. Adsorbent agglomerate according to one of the preceding claims, comprising at least three hierarchical layers (2, 3, 4, 5), preferably at least four hierarchical layers (2, 3, 4, 5).

4. Adsorbent agglomerate according to one of the preceding claims, in which the hierarchical layers (2, 3, 4, 5) represent at least 30%, preferably at least 50%, preferably at least 60% of all the layers of the adsorbent agglomerate.

5. Adsorbent agglomerate according to one of the preceding claims, in which the internal region (7) comprises an aggregate of adsorbent particles (1), in which aggregate no hierarchy of layers of adsorbent particles (1) is present.

6. Adsorbent agglomerate according to one of the preceding claims, the adsorbent agglomerate being substantially spherical.

7. Adsorbent agglomerate according to one of the preceding claims, wherein each adsorbent particle (1) included in the hierarchical layers rarchized (2, 3, 4, 5) consists of a single crystal of adsorbent or a single amorphous solid.

8. Adsorbent agglomerate according to one of the preceding claims, the adsorbent agglomerate being a zeolitic adsorbent, in particular a FAU zeolite, in particular a zeolite X, Y or A.

9. An adsorber comprising an adsorbent bed, said bed comprising a plurality of adsorbent agglomerates according to one of the preceding claims.

10. Method for separation by adsorption of a gas mixture using an adsorbent agglomerate according to one of claims 1 to 8 or an adsorber according to claim 9.

11. A separation method according to the preceding claim, the method being an air separation method.

12. Use of an adsorbent agglomerate according to one of claims 1 to 8 or of an adsorber according to claim 9 in processes for fractionating "n" and "iso" paraffins, for fractionating xylenes, alcohols, in processes for purifying hydrogen or helium.

13. A method of manufacturing an adsorbent agglomerate comprising the following steps: - providing a plurality of adsorbent particles (1), each of the adsorbent particles (1) having a volume called particle volume, - constituting at least two batches of adsorbent particles (1), each batch of adsorbent particles (1) corresponding to a targeted average particle volume of the particles constituting it, a standard deviation of the particle volume values ​​of the adsorbent particles of each batch being less than 20%, preferably less than 10%, preferably less than 5% relative to the targeted average particle volume of said batch, - an agglomeration step comprising the sub-steps: a) agglomerating the adsorbent particles (1) of a first batch into a first layer (2) of adsorbent particles (1), b) agglomerating the adsorbent particles (1) of the next batch into a next upper layer (3) of adsorbent particles (1),covering the first layer of adsorbent particles (1), the targeted average particle volume of each of the batches preceding a following batch being less than the targeted average particle volume of said following batch.,

14. Manufacturing method according to the preceding claim, in which the agglomeration step is carried out by fluidization or by rotating plate.

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