EP3830467A1

EP3830467A1 - Device for storing gas by sorption

Info

Publication number: EP3830467A1
Application number: EP19745157.8A
Authority: EP
Inventors: Michael Francis Levy; Jorn OUBRAHAM; Carsten Pohlmann; Jean-Baptiste Dementhon
Original assignee: Aaqius and Aaqius SA
Current assignee: Aaqius and Aaqius SA
Priority date: 2018-07-31
Filing date: 2019-07-31
Publication date: 2021-06-09
Also published as: FR3084722A1; CN112805498A; JP2021533310A; MA53317A; WO2020025660A1; US20210293382A1

Abstract

The invention relates to a sorption-based gas storage structure (10) comprising: - a first layer (100) comprising a sorption-based storage material, - a second layer (200) comprising: ° a first portion (201, 203) of the second layer, in contact with the first layer (100), and ° a second portion (202) of the second layer.

Description

l

SORPTION GAS STORAGE DEVICE

FIELD OF THE INVENTION The invention relates to the storage of gas by sorption.

The invention relates more specifically to a sorption gas storage structure, a sorption gas storage device, a gas storage and / or supply system, and an associated method. STATE OF THE ART

The use of gas in industry, whether in the mobility, energy, chemical or production sector, is subject to multiple constraints. In this regard, numerous gas storage devices have already been proposed. Some of these devices may include a solid material for storing a gas.

Such solid storage devices must have particular properties, in order to respond to the constraints induced by the gas and linked to the conditions of its use. Gas stored in solid form can, for example, when used as an energy carrier, power a fuel cell. In the mobility sector, it can also be used in a motor vehicle.

Depending on the intended use, the storage structures are sized in different ways depending on the choice of storage material and its size. It is for example known to provide a storage material in powdered form compressed within stacked boxes.

In any event, the management of the storage material is an essential issue to guarantee the performance of such devices. In this regard, it is for example known to have the storage material inside an enclosure.

The known systems are however exposed to problems of efficiency and homogenization of the behavior of the storage material, of robustness and of longevity of operation of the storage structures, of safety of use, of manufacturing complexity, and of economic efficiency. and energy in the implementation of said systems. By way of example, document US 2005/0188847 describes an enclosure within which a heat exchanger extends. The exchanger comprises pipes on which fins are fixed transversely, delimiting between them gaps, some of which are filled with an alloy for the storage of hydrogen in solid form. The remaining empty gaps are, in turn, configured to be crushed due to the expansion of the alloy, and this irreversibly.

DESCRIPTION OF THE INVENTION An object of the invention is to overcome at least one of the drawbacks listed above.

Another object of the invention is to allow optimized gas storage, for example more efficient or more robust, in a storage material.

Another object of the invention is to facilitate the handling of a gas storage structure, in particular during its manufacture.

Another object of the invention is to simplify the manufacture, maintenance and / or recycling of a gas storage structure, in particular by reducing the costs associated with these operations.

Another object of the invention is to reduce the mechanical stresses within a gas storage structure.

Another object of the invention is to facilitate heat exchange within a gas storage structure.

Another object of the invention is to provide a storage structure which can be easily adapted to the needs in terms of storage performance and / or gas supply.

The invention notably proposes a structure for storing gas by sorption comprising:

- a first layer comprising a sorption storage material, - a second layer comprising:

a first part of the second layer, in contact with the first layer, and comprising a thermally conductive material, of thermal conductivity greater than that of the storage material, with a view to increasing the heat transfers within the storage structure, and a second part of the second layer, comprising a material:

^■ compressible in order to deform under the action of forces exerted by the storage material during variations in the volume of the storage material during the sorption and desorption phases of the gas,

^■ greater compressibility than that of the first part material, and

^■ thermally conductive, with thermal conductivity greater than that of the storage material, with a view to increasing the heat transfers within the storage structure.

In such a structure, thanks to the second layer, the phenomena of sorption and desorption of gas by the storage material, which involve significant flows of heat, are facilitated. In addition, the second layer acts as a buffer during the operation of the storage structure, in order to distribute the mechanical stresses optimally within said structure. This is particularly advantageous when the storage of gas by sorption is reversible. Indeed, the alternation of the sorption and desorption phases causes cyclic variations in the volume of the storage material which are compensated for by the material of the second part of the second layer. In addition, this compensation can be obtained during several successive cycles, during which the material of the second part of the second layer can spread again after being compressed, unlike the interstices described in US 2005/018847 which are crushed so irreversible.

Advantageously, but optionally, the device according to the invention can also comprise at least one of the following characteristics, taken alone or in combination:

the first part material has a lower porosity than the second part material,

- the storage material is in pre-compressed powder form,

- the first part is a first underlay and / or the second part is a second underlay,

- For at least a second layer, the second sublayer is disposed between the first sublayer and a third sublayer of the second layer, in contact with another of the at least one first layer, and comprising a thermally conductive material , of thermal conductivity higher than that of the storage material, with a view to increasing the heat transfers within the storage structure,

the structure comprises an alternation of first layers and of second layers, preferably the first layers being separated two by two by one of the second layers,

the structure comprises alternating wafers, preferably wafers which are mechanically independent of each other, preferably each first layer and / or each second layer forming a wafer, and

the sorption storage material is a reversible sorption gas storage material,

- The second layer is adapted to compensate by elastic deformation the respiration of the first layer during storage and / or supply of gas.

The subject of the invention is also a device for storing gas by sorption comprising:

- a storage structure as previously described,

- an enclosure, the storage structure being arranged inside the enclosure.

The invention also relates to a gas storage and / or supply system comprising a storage device as described above, and a gas utilization unit.

The invention also relates to a method for storing and / or supplying gases by means of a storage structure as previously described, or of a storage device as previously described, or of a storage system. and / or gas supply as previously described, comprising a step of storing gas by sorption by the first layer.

the method further comprises the steps of:

o plastic compression of the materials of the second layer, and o elastic compression and / or decompression of the materials of the second layer.

DESCRIPTION OF THE FIGURES Other characteristics, objects and advantages of the present invention will appear on reading the detailed description which follows and with reference to the appended drawings given by way of non-limiting example and in which:

FIG. 1 represents a gas storage structure according to an exemplary embodiment of the invention,

- Figure 2 shows the evolution of a second layer of the storage structure of Figure 1, during the operation of said structure,

FIG. 3 illustrates a gas storage device according to an exemplary embodiment of the invention,

FIG. 4 represents a gas storage and / or supply system according to an exemplary embodiment of the invention, and

- Figure 5 is a flowchart illustrating a method of storing and / or supplying gas according to an exemplary implementation of the invention.

DETAILED DESCRIPTION OF THE INVENTION

With reference to the figures, we will now describe a structure and a device for storing gas by sorption, as well as a system and method for storing and / or supplying gas.

The gas stored can be of any kind and of any type. For example, the storage structure can store alone, or in combination, hydrogen, ammonia, water vapor, oxygen, and / or carbon dioxide.

Storage structure

With reference to FIG. 1, a sorption gas storage structure 10 comprises a first layer 100 and a second layer 200.

The first layer 100 is configured to store gas by sorption. To do this, it can comprise a material for storage by sorption.

The sorption storage material can be a reversible or irreversible sorption gas storage material. By reversible is meant that a material initially charged by sorption and which has been at least partially discharged by sorption can be at least partially recharged in the medium in which the material is placed. In the case of an irreversible sorption, the gas can only be desorbed once and can no longer be absorbed again by the material.

Advantageously, the storage material can be in pre-compressed powder form. Indeed, this shape facilitates the transport of the storage material because it is then easier to handle and has a smaller volume. In addition, this shape is more suitable for the sorption storage operation, because it is more stable, facilitates heat transfer, makes the expansion of the storage material more homogeneous.

In addition, the material can have an optimized porosity in order to increase the volumetric storage capacity of the storage structure, but also to accommodate variations in volume of the second layer 200. For example the porosity of the storage material is between 10 vol.% and 50 vol.%, and is preferably between 25 vol.% and 35 vol.%. By porosity is meant the ratio of the volume not occupied by the storage material within a given volume of the storage material, over said given volume. In other words, the porosity corresponds to the ratio of the volume not occupied by the storage material, over its apparent volume, that is to say that the porosity is equal to the ratio between the theoretical density at which the apparent density is subtracted from the theoretical density. In any event, the pre-compressed powder form makes it possible to control the porosity of the storage material.

In addition, the storage material can include:

a material suitable for forming a metal hydride, preferably of the Mghh, NaAlhU, LiNhh, and / or LiBhU type, and / or a material suitable for forming an intermediate alloy, preferably of the TiMn2, TiC, LaNi ₅ , FeTi, TiV, and / or TiZr type, and / or

- a material suitable for forming an ammonia salt, preferably of the BaCh, and / or CaCh type, or

- a material suitable for forming a hydroxide, preferably of the type

CaO, and / or Ca (OH) 2, or

- a material suitable for forming an oxide, preferably of the PbO, and / or CaO type.

The applicant has in fact noticed that the above materials are particularly suitable for storing and / or supplying gas such as hydrogen, ammonia, water vapor, oxygen, and / or carbon dioxide. This is not, however, limiting, since such materials can also be particularly suitable for other types of gas.

The second layer 200 can, for its part, comprise a material:

- thermally conductive, with a higher thermal conductivity than that of the storage material, with a view to increasing the heat transfers within the storage structure 10, and

compressible in order to deform under the action of forces exerted by the storage material during variations in the volume of the storage material during the sorption and desorption phase of gas.

Thanks to the second layer 200, the phenomena of sorption and desorption of gas by the storage material, which involve significant heat flows, are facilitated. In fact, the heat transfers are thus distributed homogeneously throughout the entire storage structure 10, which reinforces its efficiency and durability. In fact, the heat can be transported and easily extracted from the first layer 100, which ensures the rapid storage and / or destocking of the gas within the storage structure 10. The energy stored by a given mass of material of storage is therefore advantageously increased. Advantageously, the dimensions, the shape, and the relative positioning of the first layer 100 and of the second layer 200 make it possible in particular to optimize the heat transfers within the storage structure 10. For example, when the first layer 100 and the second layer 200 extend in a preferred longitudinal direction, as visible in FIG. 1, the layer thickness in a section orthogonal to the longitudinal direction is a lever for possible optimization of the heat flows at within the storage structure 10. Alternatively, or in combination, providing a porosity gradient of storage material within the first layer 100, in a radial direction relative to the longitudinal direction, also constitutes a possible optimization path. heat exchanges within the storage structure 10. Indeed, it is observed that, when the first layer 100 and the second layer 200 extend in a longitudinal direction, the radial direction constitutes a preferred direction of heat exchange at within the storage structure 10. In any event, most of the heat emitted or received by the first layer 100 is transferred by the second layer 200.

In addition, the second layer 200 acts as a buffer during the operation of the storage structure 10. In fact, the second layer 200 compensates for the variations in volume of the storage material during the sorption and desorption phases of gas, and thus preserves the mechanical coherence of the storage structure 10. In this way, the volumetric capacity of the storage material is advantageously increased, since it is no longer necessary to provide empty spaces within the storage structure 10, as in the storage system described in document US 2005/0188847. Finally, the second layer 200 makes it possible to distribute the mechanical forces arising from variations in the volume of the storage material in operation.

The gas can be conveyed and / or extracted from the storage material by any suitable diffuser (not shown). Advantageously, the diffuser extends in a longitudinal direction which corresponds to the preferred direction of the storage structure 10, and the gas is distributed from and / or to the storage material in a direction radial to this preferred direction.

Alternating structure

As shown in FIG. 1, in one embodiment, the storage structure 10 comprises the first layer 100 and the second layer 200, alternately. Preferably, the storage structure 10 comprises an alternation of first layers 100 and second layers 200, the first layers 100 preferably being separated in pairs by one of the second layers 200. The alternating distribution notably facilitates the distribution of the stresses thermal and mechanical within the storage structure 10. In addition, an alternating structure is easily reproducible on an industrial scale, both at the manufacturing and maintenance stage of the storage structure 10. In addition, such a structure can easily be adapted according to the needs in terms of storage performance and / or gas supply. Finally, such a distribution allows a compactness of the storage structure 10 which can prove to be particularly advantageous for applications such as transport, for example automobile.

Advantageously, the storage structure 10 comprises alternating wafers, each first layer 100 and / or each second layer 200 preferably forming a wafer. Privileged, but however optional, the wafers are mechanically independent of each other. Such a configuration can in particular facilitate the handling of the different elements of the storage structure during the various operations associated with the manufacture, maintenance and / or recycling of the storage structure 10. In addition, the configuration in wafer promotes geometric optimization distribution and distribution of materials within the storage structure 10. In addition, this configuration is more suited to the operation of sorption storage, because it is more stable, facilitates heat transfer, makes the material expand more homogeneous storage. Thus, the gas can be better distributed throughout the entire storage structure 10 when loading the storage material.

Second layer parts

Still with reference to FIG. 1, in one embodiment, the second layer 200 may comprise a first part of the second layer 201, 203 in contact with the first layer 100, and a second part of the second layer 202.

In this configuration, the first part 201, 203 can then comprise a thermally conductive material, of thermal conductivity greater than that of the storage material, with a view to increasing the heat transfers within the storage structure. The second part 202 may, for its part, comprise a compressible material in order to deform under the action of forces exerted by the storage material during variations in the volume of the storage material during the sorption and desorption phase. gas. In addition, the second part material 202 is advantageously of greater compressibility than the first part material. By compressibility, we understand the capacity of a material to decrease its volume when subjected to a given compression force. Thus, for the same compression force, the reduction in volume of the second part material 202 is greater than the reduction in volume of the first part material 201, 203. In other words, to obtain a given reduction rate of the volume of the first part material 201, 203 and of the second part material 202, greater compressive forces are required for the first part material 201, 203 than for the second part material 202. In any event, the second part material 202 is also thermally conductive, with a higher thermal conductivity than that of the storage material, with a view to increasing the heat transfers within the storage structure 10.

The functions of the second layer 200 are then partially distributed between the first part 201, 203 and the second part 202. In this way, each of these functions can be optimized independently of each other, which improves the efficiency overall of the storage structure 10, and makes it possible more to adapt the storage structure 10 as a function of gas supply and / or storage needs. In addition, the presence of a thermally conductive material in each of the two parts 201, 202, 203 guarantees that the heat exchanges within the storage structure 10 are facilitated in order to distribute the heat evenly throughout the storage structure. 10.

The first part material 201, 203 can be identical to the second part material 202. This allows an advantageous cost reduction and a simplification of the manufacture of the storage structure 10. Alternatively, the first part material 201, 203 can be different from the second part material 202. This promotes the adaptation of the storage structure 10 in order to optimize its storage and / or supply capacities for a given gas.

Furthermore, the first part material 201, 203, and / or the second part material 202, can comprise a matrix comprising graphite, for example natural graphite, for example expanded natural graphite. Alternatively, or in addition, the first part material 201, 203 may comprise a metal, for example aluminum or copper. Alternatively, or in addition, the second part material 202 may comprise a foam. The applicant has in fact noticed that these materials have adequate compressibility and / or heat transfer properties to fulfill the functions he

first part 201, 203 and / or second part 202 of a storage structure 10.

The first part material 201, 203 may furthermore have a lower porosity than the second part material 202. The porosity indeed constitutes a parameter influencing both the compressibility and the thermal properties of a material. Consequently, this difference in porosity favors the deformation of the second part 202 under the action of forces exerted by the storage material during variations in the volume of the storage material during the sorption and gas desorption phase, and allows the first part 201, 203 to increase the heat transfers within the storage structure 10. More specifically, the first part material 201, 203 can have a porosity of less than 50%, preferably less than 15%, and preferably less than 5%.

With reference to FIG. 2, the mechanical properties of the second layer 200 change during the various operating cycles of the storage structure 10.

In fact, the first operating cycles of the storage structure 10 will make it possible to activate the first layer 100. More precisely, during the first loading and / or unloading cycles of the storage structure 10, the storage material included in the first layer 100 will acquire its full storage capacity by sorption. This initial conditioning can be implemented during loading and / or unloading cycles which may be of long duration and / or carried out at high temperature and / or carried out at high pressure. In this regard, it should be noted that, when the storage material is in pre-compressed powder form, activation is facilitated since the number and duration of the first loading and / or unloading cycles decrease. Gradually, the quantity of gas stored, then supplied, by the first layer 100 increases, as and when successive loading and / or unloading, until reaching an expected level of storage under given temperature and pressure conditions. This expected level corresponds to the maximum quantity of gas that it is possible to store in the first layer 100 at a given temperature and pressure. Once this level is reached, the storage material is activated. However, this or these first operating cycles cause significant changes in the volume of the first layer. This leads to a plastic compression of the second layer 200, essentially by plastic compression of the second part of the second layer 202, as visible in FIG. 2.

Thereafter, the volume variations of the first layer 100, during storage and / or supply of gas, are less significant than during the activation of the storage material. This is called breathing of the first layer 100. These small variations in volume are compensated for by an elastic deformation of the second layer 200 as visible in FIG. 2.

Thus, the first part 201, 203 may have, before activation of the storage material, a thickness of less than 5 millimeters, preferably of approximately 2 millimeters, and in a preferred manner of approximately 1 millimeters. The second part 202 can, for its part, present, before activation of the storage material, a thickness of between 2 and 10 millimeters, preferably between 2 and 8 millimeters, and preferably between 2 and 4 millimeters. The applicant has in fact noticed that these thicknesses guarantee the best thermal conductivity within the storage structure 10, but also a good compensation for the forces exerted by the storage material during variations in the volume of the storage material during gas sorption and desorption phases. In any event, the plastic compression of the second layer 200 leads to a reduction in height of the second layer 200 of the order of 20 to 60% relative to its initial height, before activation, and the elastic compression leads to a reduction in height of the second layer 200 of the order of 80 to 99% relative to its initial height, before activation.

In addition, the second part material 202 may have, before activation of the storage material, a porosity greater than 70%, preferably more than 80%, and more preferably more than 95% and, after activation of the storage material, a porosity greater than 20%, preferably more than 30%, and preferably between 45% and 60%. The applicant has in fact noticed that these porosities guarantee the best thermal conductivity within the storage structure, but also good compensation for the forces exerted by the storage material during variations in the volume of the storage material during gas sorption and desorption phases.

As shown in FIG. 1, the first part 201, 203 can be a first sub-layer and / or the second part 202 can be a second sub-layer. This guarantees a structural homogeneity which facilitates the manufacturing, maintenance and / or recycling operations of the storage structure 10. In in addition, the functions of the second layer 200 can be ensured while retaining a good compactness of the storage structure 10. This is not however limiting, since other forms of first part 201, 203 and second part 202 are conceivable. For example, the second layer 202 can also be structured in angular sectors, each sector corresponding to one or the other of the first part 201, 203 and of the second part 202.

Advantageously, with reference to FIG. 1, for at least a second layer 200, the second sublayer 202 can be disposed between the first sublayer 201 and a third sublayer of second layer 203, in contact with another of the at least one first layer 100, and comprising a thermally conductive material, of thermal conductivity greater than that of the storage material, with a view to increasing the heat transfers within the storage structure. In this configuration of the second sandwich layer 200, the second sublayer 202 is not in contact with the first layer 100. This configuration allows optimization of the heat transfers through the storage structure 10.

Storage device

With reference to FIG. 3, a sorption gas storage device 30 comprises a storage structure 10 according to any one of the embodiments previously described, and an enclosure 40, the storage structure 10 being arranged inside. of enclosure 40.

The presence of the enclosure 40 facilitates the transport and handling of the storage structure 10, but also its integration within global structures, such as a car for example. In addition, the presence of the second layer 200 makes it possible to alleviate the mechanical and thermal stresses that the storage structure 10 exerts on the enclosure 40, in operation. Thus, such a storage device 30 has increased robustness. Gas storage and / or supply system

With reference to FIG. 4, a gas storage and / or supply system 50 comprises a sorption gas storage device 30 according to any of the previously described embodiments, and a gas utilization unit 60 .

The gas utilization unit 60 can, for example, be a fuel cell of a motor vehicle when the stored gas is hydrogen.

Gas storage and / or supply process

Referring to Figure 5, a method of storing and / or supplying gas E by means of a sorption gas storage structure 10 and / or a sorption gas storage device 30 and / or d a gas storage and / or supply system 50, according to any one of the embodiments described above, comprises a step of storing gas by sorption E1 by the first layer 100.

Advantageously, the method E further comprises the steps of plastic compression E2 of the second layer materials 200 and of elastic compression and / or decompression E3 of said second layer materials 200. These steps E2, E3 correspond to the activation processes E2 then of E3 breathing previously described.

Claims

1. Gas storage structure by sorption (10) comprising:

a first layer (100) comprising a sorption storage material,

a second layer (200) comprising:

a first part of the second layer (201, 203), in contact with the first layer (100), and comprising a thermally conductive material, of thermal conductivity greater than that of the storage material, with a view to increasing the heat transfers to the within the storage structure (10), and o a second part of the second layer (202), comprising a material:

^■ greater compressibility than that of the first part material (201, 203), and

^■ thermally conductive, with a higher thermal conductivity than that of the storage material, in order to increase the heat transfers within the storage structure (10).

2. Storage structure (10) according to claim 1, in which the first part material (201, 203) has a lower porosity than the second part material (202).

3. Storage structure (10) according to one of claims 1 and 2, wherein the storage material is in pre-compressed powder form.

4. Storage structure (10) according to one of claims 1 to 3, in which the first part (201, 203) is a first sub-layer (201, 203) and / or the second part (202) is a second sub-layer (202).

5. Storage structure (10) according to claim 4, in which for at least one second layer (200), the second sub-layer (202) is disposed between the first sub-layer (201) and a third sub-layer of second layer (203), in contact with another of the at least one first layer (100), and comprising a thermally conductive material, of thermal conductivity greater than that of the storage material, with a view to increasing the heat transfers to the within the storage structure (10).

6. Storage structure (10) according to one of claims 1 to 5, in which the structure (10) comprises alternating first layers (100) and second layers (200), preferably the first layers (100) being separated two by two by one of the second layers (200).

7. Storage structure (10) according to one of claims 1 to 6, wherein the structure (10) comprises alternating wafers, preferably wafers mechanically independent of each other, preferably each first layer (100) and / or each second layer (200) forming a wafer.

8. Sorption gas storage device (30) comprising:

a storage structure (10) according to one of claims 1 to 7, an enclosure (40), the storage structure (10) being arranged inside the enclosure (40).

9. A gas storage and / or supply system (50) comprising a storage device (30) according to claim 8, and a gas utilization unit (60).

10. A method of storing and / or supplying gas (E) by means of a storage structure (10) according to one of claims 1 to 7, or of a storage device (30) according to claim 8 , or a system (50) according to claim 9, comprising a step of storing gas by sorption (E1) by the first layer (100).

11. A method of storing and / or supplying gas (E) according to claim 10, further comprising the steps of: plastic compression (E2) of the materials of the second layer (200), and

elastic compression and / or decompression (E3) of the materials of the second layer (200).