Patent Application
20240294373
The storage and the production of the dihydrogen is a major challenge for the use of this energy carrier. In this invention, we propose a method for storing the dihydrogen in a suspension of hydrides using alkali metal alloys, known as “LAMPHY®”, and a device for producing dihydrogen from the reaction of the LAMPHY® with a jet of water projected at high speed into a cyclonic reactor.
The technical background comprises the documents US-A1-2014/072498, EP-A1-0 081 669 and the article “The Chemistry of Hydrogen in Liquid-Alkali-Metal Mixtures Useful as Nuclear Reactor Coolants—I. Sodium-Potassium Eutectic”, by Compere Edgar L. et al, Nuclear Science and Engineering, vol. 28, 0o. 3, 13 juin 1967, pages 325-337, XP055862604.
The storage and the production of dihydrogen are major energy challenges for the 21st century, since the dihydrogen represents a serious alternative to both fossil fuels and nuclear energy.
The hydrogen storage currently represents a technological barrier to the development of this energy, both for the on-line energy production, domestic and industrial electrical energy, and for the mobility energy used in the vehicles in general.
The small size of this molecule means that even though it has 4 times more energy than petrol, for the same mass it occupies 100 times more volume at atmospheric pressure. For 1 kg of dihydrogen taken at atmospheric pressure, 11 m3 of storage would be required, which poses considerable storage and transport problems.
One of the most successful methods of storing and transporting dihydrogen is to compress it in tanks. Because the dihydrogen is the smallest molecule, the walls of most tanks used to store the dihydrogen remain more or less porous, causing the stored hydrogen to volatilize through leaks of varying speed.
However, the 300-bar storage tanks offer attractive storage performance. These tanks are suitable for large vehicles and offer weak autonomy.
To increase the autonomy and therefore the amount of dihydrogen stored in the same volume, the storage pressure is tending to be increased from 300 bar to 700 bar with new-generation tanks.
But for the time being, whatever the technology used, the tanks that use the pressure to store the dihydrogen remain permeable for varying lengths of time and are therefore incompatible for the long-term storage.
Alternatives for increasing the storage time and reducing the pressure required to store the same quantity of dihydrogen include introducing carbon powders, zeolites or glass beads into the tank.
Nevertheless, the compression of dihydrogen consumes between 5 and 15% of the potential energy for the compression phase.
One of the alternatives to the compression is the liquefaction at (−252.87° c.), but this liquefaction is extremely energy-intensive, and the conservation of the liquid dihydrogen requires technologies that are still costly, both for the tanks and for the pressure-maintaining pumps.
An alternative development solution is the storage of the dihydrogen in “Liquid Organic Carrier Hydrogen”, also referred by the acronym LOCH. The hydrogen bonded to an organic molecule by a hydrogenation offers a high storage density. The storage reaction involving hydrogenation is usually exothermic. The monopolisation of the hydrogen requires this bond to be broken in order to reform the dihydrogen, usually through an endothermic reaction, which penalises the energy efficiency at the point where the dihydrogen is used.
Alternatives to the compression and to the liquefaction are being sought in the form of solid storage using metal hydrides, the most popular of which is currently the magnesium hydride MgH2.
These hydrides come in the form of powders or agglomerates of varying sizes. The fact that hydrides are often pyrophoric powders makes their use more complex, particularly their packaging and their distribution, while ensuring that they are isolated from oxygen and from humidity.
Nevertheless, the storage in hydride form is very promising, since this chemical form is much more stable than the gaseous or liquid form, with one of the best storage capacity performances currently available at ambient temperature, in a controlled atmosphere or in mineral oils.
However, the transition from hydride to hydrogen is still problematic. None of the proposed methods is satisfactory for successful industrial applications. Several methods involve heating the hydride to release the dihydrogen. In addition to the energy consumption, which affects the efficiency, the significant changes in density between the metallic and hydride forms pose storage problems, with the fatigue of the containers during the recharge/discharge cycles.
One alternative is to use the hydride as a chemical component to produce the hydrogen on the fly by a chemical reaction between the hydride and the water, or another proton donor based on reactions already used to produce the dihydrogen on a small scale. This same type of reaction can be obtained with the metal powders such as aluminium.
The problem is that the reaction is highly exothermic and violent, and controlling the flowing of the powders requires containment gases to control the accidental ignition.
To control this reaction and its implementation more precisely, one solution consists of conditioning the hydride of the magnesium in a muddy phase, referred to as a “goop”, obtained by mixing various additives, in particular metal halides and various other additives designed to reduce the violence of the reaction.
This shape offers the advantage of an easier handling, allowing the water and the goop to be mixed using pumps or pistons. However, the behaviour of the long-term storage is not described.
On the other hand, the stabilisation of the goop leads to less reactivity of the magnesium hydride, which is more easily pacified by the hydroxide plates resulting from the reaction with water.
The storage capacity of dihydrogen by the goop is limited by a non-negligible volume of the mixture made up of various catalysts and other additives which do not intervene directly to sequester the dihydrogen.
In addition, these adjuvants comprising nanoparticles such as zirconium or other nanoparticles may be toxic to the environment and the living organisms.
Generally speaking, the additives are found in the brine resulting from the reaction of the goop with the water, which complicates the problem of recycling the brine obtained and may ultimately pose environmental problems, particularly the halogenated salt fractions resulting from the reactions.
In the context of this invention, we propose an alternative method for storing and producing dihydrogen, combined with implementing devices, which allow to offer highly responsive fluid implementation, eliminating the passivation problems, while allowing to maintain a high dihydrogen efficiency and a long storage life.
The present invention relates to a dihydrogen storage system, characterised in that it comprises a suspension of figured elements, in the form of hydride particles with an average diameter of between 1 nm and 800 μm, suspended in an alloy of at least two alkali metals, chosen from Na (sodium), K (potassium) and Li (lithium). The hydride particles form a stable suspension in the alloy.
The system according to the invention may comprise one or more of the following characteristics, taken alone or in combination with each other:
The present invention also relates to a method for storing the dihydrogen in a dihydrogen storage system as described above, characterised in that it comprises a step of preparing an alloy of at least two alkali metals, selected from Na (sodium), K (potassium) and Li (lithium), a step of preparing a plurality of hydride particles, and a step of mixing between the alloy and the particles to obtain a suspension of the particles in said alloy and the formation of said dihydrogen storage system. The hydride particles form a stable suspension in the alloy.
The method according to the invention may comprise one or more of the following characteristics or steps, taken in isolation from one another or in combination with one another:
The present invention also relates to a method for producing dihydrogen from a dihydrogen storage system, said dihydrogen storage system comprising a suspension of elements, in the form of hydride particles with an average diameter of between 1 nm and 800 μm, suspended in an alloy of at least two alkali metals, chosen from Na (sodium), K (potassium) and Li (lithium), the method comprising a step of reacting the dihydrogen storage system with H2O.
In this application, the term “figured elements” refers to elements dispersed and suspended homogeneously in a liquid to form a suspension (or stable suspension or colloidal suspension). A suspension (or stable suspension or colloidal suspension) is a stable, homogeneous dispersion of a solid in a liquid—as opposed, for example, to a mud or a slurry in which particles are precipitated. The suspension is therefore stable and homogeneous, meaning that the particles are evenly distributed in the alloy and do not precipitate over time.
The method according to the invention may comprise one or more of the following characteristics or steps, taken in isolation from one another or in combination with one another:
Lastly, the present invention relates to a device for implementing a method as described above, characterised in that it comprises a cyclone-type reactor for the reaction between H2O and the LAMPHY, this reactor comprising at least one cyclonic structure which allows the formation of a vortex, and a column of gas and vapour rising to the centre of the reactor, and having in the low position a device for extracting the heaviest solid and liquid materials, and in the top part a central collector for the vapours and gases.
The device according to the invention may comprise one or more of the following characteristics or steps, taken in isolation from each other or in combination with each other:
Further characteristics and advantages of the invention will become apparent from the following detailed description, for the understanding of which reference is made to the attached drawings in which:
For example, an alloy with 78% K and 22% Na will remain liquid between −12° C. and 750° C.
For example, for such a mixture, the dynamic viscosity is given by
μ=−3.759×10−12×t3+6.3008×10−9×t2−3.729×10−6×t+9.9806×10−4 kg m−1s−1
The alloys obtained will have viscosity properties that can be adapted according to the proportions of the metals, ranging from a liquid with a viscosity close to that of the mercury, to a paste that can be structured into filaments, and from a liquid with a behaviour close to that of a Newtonian liquid to a paste with a non-Newtonian behaviour.
The alkali metal alloy is used to make a suspension of figured elements comprising metal hydrides in particulate form with a diameter of between 1 nm and 800 μm, preferably between 50 nm and 50 μm.
The metal hydrides will be selected without being exhaustive from the following hydrides: Li H, Na H, K H, Ca H2, Mg H2, BeH2, Al H3, InH3; TIH3, GaH3, BH3, Al H4−, InH4−; TIH4−, GaH4−, BH4−.
The proportion of metal alloy in the suspension can vary from 3% to 97%, with a proportion of hydrides varying from 97 to 3%. The proportions can go as far as making the mixture solid so that the mixture can be shaped into filaments so that they can be stored in spools of yarn.
This solid or highly viscous paste state, allowing the filament structuring, is obtained either by increasing the viscosity of the alkaline metal alloy by varying its composition to make it viscous, or by increasing the proportion of the nanoparticles in a low-viscosity alloy, or by any combination of these two means.
The anionic hydrides such as dH4− taken from ALH4−, BH4− etc. with, d representing AL, B, Ga, In, TI may be added to the suspension with any m2+ cation such as Ca2+, Mg2+, Be2+ or n+ such as Na+, K+, Li+ in the form m d2H8 or n dH4.
In general, all the pyrophosphoric metal hydrides can be used as hydride sources, comprising depleted uranium.
The non-pyrophosphoric hydrides such as the hydride of titanium TiH2 or of zinc ZnH2 can be used. These hydrides are stable in contact with air and water, and react very slowly. To be decomposed, these hydrides need to be activated, for example by heating them. The exothermic energy released by the constituent elements of the alkali metal alloy, and/or any other hydrides present in the suspension, when the suspension reacts with water, allows to activate these non-pyrophosphoric hydrides to decompose and react in turn with water.
In some embodiments, each illustrated element may comprise a hydride of the same nature or any combination of hydrides of different natures,
In other embodiments, the figurative elements comprise a plurality of different figurative elements wherein each figurative element comprises a hydride of the same nature.
In some embodiments, the metal alloys may be supplemented up to 50% of their mass by one or any combination of alkaline earth metals such as Be, Mg, Ca, metals such as B, Al, Ga, In, TI or phosphorus such as P, preferably black phosphorus, red phosphorus or white phosphorus or any other phosphorus phase or other elements in these categories. Certain metals such as Cu, Fe and Zn can be added to the alkali metal alloy in a minority form. Among other things, these metals allow the formation of induced hydrides such as CuH, FeH2 and ZnH2. The same applies to phosphorus, which could allow to produce PH3 hydrides in the alloy.
The alloys can be obtained by mechanical mixing under argon, for example by lamination, which causes a mechanical mixing of the metals and other elements to obtain said alloys.
The viscosity of the alloys can be adjusted by adding Gallium in a proportion varying from 0.005% to 10% of the final mass of the alloy.
To facilitate the mixing to form the metal alloy, amalgams with Gallium can be produced, in particular for the use of non-alkaline and non-alkaline-earth metals.
The hydrides can be obtained by rolling or extrusion in a dihydrogen atmosphere.
The hydride particles can also be obtained by pulverization a spray of molten metal in a cold dihydrogen atmosphere, or by projecting metal into a hydrogen plasma.
The hydride particles can be obtained by causing “n” to act, selected from (Li, Na, K) and “d” to act, selected from (Mg, Ca, Be) or “E” to act, selected from (Al, B, Ga, In, TI)
2n+d+H2→dH2+2n
6n+2E+3H2→2EH3+6n
8n+2E+4H2→2nEH4+6n
8n+2E+4H2+d→dE2H8+8n
The efficiency of the dihydrogen production will depend on the composition of LAMPHY.
The metallic alloys of composition type “n” taken from (Li, Na, K) will produce dihydrogen according to the reaction:
n+H
2O→nOH+½H2
The metal hydrides of the nH type, “n” chosen from (Li, Na, K) will produce dihydrogen according to the reaction
nH+H2O→nOH+H2
The metal hydrides of the dH2 type, “d” selected from (Mg, Ca, Be)
dH2+2H2O→d(OH)2+2H2
The metal hydrides of type EH3, “E” chosen from (AL, B, Ga, P)
EH3+3H2O→E(OH)3+3H2
The metal hydrides of the nEH4 type, where “E” is selected from (AL, B, Ga, etc.) and “n” is selected from (Li, Na, K)
nEH4+4H2O→E(OH)3+4H2+nOH
The metal hydrides of the dE2H8 type, “E” selected from (AL, B, Ga etc.) “d” selected from (Mg, Ca, Be)
dE2H8+8H2O→2E(OH)3+8H2+d(OH)2
Because of the electronegativities of the different elements K(0.82)<Na (0.93)<Li (0.98)<Be<Ca (1)<Mg(1.31)<Be (1.57)<TI(1.62)<In(1.78)<Ga(1.81)<AL(1.61)<B(2.04)<P(2.19)
Readjustment reactions between the hydrides themselves and the hydrides and the elements of the alloy composition may eventually take place and modify the nature of the hydrides without changing the hydride load (H−) of the LAMPHY
av(H)j+bH→bv(H)j+aH,
av(H)j+b→bv(H)j+a,
and
a(H)j+jb→jb(H)+a
However, for reasons:
One remedy for making the reactions complete and obtaining the expected efficiencies is to acidify the pH of the water used for the reaction and add a mechanical action to remove the layers (calluses) of hydroxide that protect the LAMPHY elements from the water, particularly the hydrides, preventing them from reacting with the water.
The experiments are carried out according to the following protocol:
The mixture is then milled with a pestle.
The milled material is returned to an argon atmosphere and weighed.
The mixtures are then pipetted into a graduated pipette
The expression “
1 g of LAMPHY is introduced into the balloon 1 by a drop by drop system, where each drop is introduced after the previous drop has completely dissolved in the water.
Each drop of LAMPHY floats on the surface of the water with very rapid translational movements, causing shocks to the walls.
Once the drop has completely dissolved, the pump empties the atmosphere from the balloon 1 into the balloon 5.
The operation is repeated until 1 g of LAMPHY 6 is dissolved in the water contained in the balloon 1.
The contents of the balloon 1 are then evaporated and weighed once dry. The difference in weight is used to estimate the quantity of X(OH); formed. Based on the composition of the LAMPHY and the expected chemical equations presented in Chapter 5, the amount of dihydrogen produced is calculated.
The closed balloon 9 is maintained vertical perfectly still for 2 minutes between −170 and −78° C. in order to decant the heavier argon which remains at the bottom of the balloon from the lighter hydrogen which remains above the argon, in the upper part of the balloon. The plug is suddenly removed in the presence of oxygen and a flame. A characteristic detonation allows to reveal the dihydrogen formed.
However, in a practical operating application, the LAMPHY must be implemented in a reactor that eliminates the passivation problems by forming a plate of hydroxide X(OH)j, also referred to as callus, which inhibits the reaction of the LAMPHY with the water in a stoichiometric reaction when the water is not in excess.
The inhibition of the reaction by passivation can be avoided by means of a device for mixing the water 15 and the LAMPHY 12,13 comprising two inlet nozzles allowing a dynamic mixing of the water and of the LAMPHY such that a first nozzle
The force of the water pulverizing the filament is such that the chemical reaction can take place, without a callus of X(OH); being able to form sufficiently to inhibit the reactions.
In a particular mode, the inhibition of the reaction between the LAMPHY and the water, by the formation of metal hydroxide calluses on the surface of the hydride particles, including the hydride particles formed by reaction of the metal alloy with the water, is avoided by projecting the reaction mixture, in the form of a pulverize or spray
In a preferred embodiment, the nozzle 11 dispensing the LAMPHY filament will be arranged at the inlet 21 of a roofless capillary array 20, such that the outlet of the nozzle 11 is in a plane that is more or less tangential, or even parallel, to the inlet 21 of the capillaries, so that the advance of the filament pushes the LAMPHY filament (extruded or solid) above the inlet, or into the inlet of the roofless capillary array. The nozzle 14 of the water jet is then arranged above the entrance to the capillary array at an angle such that the jet pulverize the LAMPHY, pushing the solution and/or suspension, and the particles obtained after pulverization, into the capillary array, causing the whole to migrate within the roofless capillary array, thus allowing the various components of the pulverize to react with each other during their passage through the capillary array while accelerating the products in the capillary array under the action of the gases emitted.
The device can be augmented by arrays of capillaries with several inlets, preferably parallel to each other, opposite which are arranged nozzles producing jets of pressurised water and LAMPHY filaments at suitable angles.
The solutions formed and the gases swirl to the lower cone of the cyclone
In some embodiments, a filter
In an even more specific embodiment, the filter 25 will be permeable only to the dihydrogen, in other embodiments the filter will be permeable only to the hydrogen ions H+ or to a combination H+/H2
The endless screw will continue, for example, with the hub of a mill
In a particular embodiment, the acid chosen will be CO2, either injected directly into the cyclone or dissolved in the water circulating in the nozzle 14 in the form of di-hydrogen carbonate H2CO3 or hydrogen carbonate HCO3−
In some embodiments, hydrogen carbonates may be injected in the form Xj+ (HCO3−)j, such that “X” is taken from n+, d2+E3+ and “j” is between 1 and 10.
These acids will neutralise the hydroxy ions produced, such as
X(OH)j+j(H2CO3)→X(HCO3)j+jH2O
or
X(OH)j+jn(HCO3−)→Xn(CO3)j+jH2O
These reactions can be used as a support to sequester CO2 in the form of a bicarbonate or carbonate stabilised by an n+, d2+, E3+ cation. The carbonate anions and their counterions can be isolated dry in crystalline form by evaporating the brines obtained.
In a particular embodiment, the abrasive elements 18 may be nanodiamond particles with a size of between 4 nm and 500 nm.
These could also be zirconium particles between 4 nm and 500 μm or silicon carbide particles between 4 nm and 500 μm, and more generally any kind of abrasive elements.
When the pulverized LAMPHY/H2O mixture is projected onto the internal wall of the cyclone, the array of pillars of the mixer arranged on the internal wall of the cyclone will form obstacles to the linear passage of the LAMPHI/H2O mixture, causing shocks and turbulence which destabilise the hydroxide calluses and promote the reaction of the water on LAMPHY.
In this embodiment, the centre of the hub
The material from the first cyclone will be conveyed into the second cyclone by the endless screw 27 and the mill 28, such that the material falls into the second cyclone, onto a conical form
A tangential inlet of CO2
The heavier materials, such as water, metal hydroxides, carbonates, hydrogen and dihydrogen, accumulated in the lower cone of the second cyclone, can be pressed and evacuated by an extraction device 26 Bis.
In addition to the reactions described, reactions such as
CO2+X(OH)j→X(CO3H)j
On the other hand, the reactivity of the LAMPHY to oxygen requires a packaging that offers a good isolation from oxygen and water.
Different models of pump or press can be used to feed the nozzle 11.
But in a particular application, the LAMPHY will be packaged in a tube 42 made of metal, steel, aluminium, composite or plastic such as PVC or polyurethane, polycarbonate etc. or any other material offering a good sealing against oxygen and inert for LAMPHY.
The tube will have a diameter of between 1 cm and 20 cm, for example, and a length of between 1 cm and 100 cm.
One end of the tube will be conical in shape with a valve 43 at its summit so that when the valve is screwed in, it is pushed back allowing the valve to open and when the valve is screwed out, the valve is closed again.
The other end of the tube will be closed by a movable piston 44, whose internal face of the tube will be cone-shaped to complement the conical end of the tube.
LAMPHY will be stored in the tube between the valve and the piston.
The piston 44 can be equipped with a joint 45 for the sealing, or alternatively the internal face of the tube can be made of a material that is deformable when the piston passes through, to guarantee a perfect sealing.
In some embodiments, the piston is made of a material that is sufficiently flexible for its deformation to guarantee a sealing.
In some embodiments, the piston will have a housing
The endless screw have a thread preferably greater than 45° to prevent a flowing under the sole action of the pressure, without the endless screw 49 being in motion. Only the movement of the endless screw can move the LAMPHY forward in the Nozzle 11 through the grid 54 located at the end of the endless screw. The motion of the screw is preferably ensured by a stepping motor 55 or a brushless motor. The gas used to pressurise the piston is preferably argon or CO2.
In this configuration, the CO2 produced will be stored in the form of hydrogen carbonate or carbonate and cation.
In some embodiments, the heat transfer fluid will be a LOCH in its hydrogenated form, so that the thermal energy captured in the reactor wall activates the dehydrogenation reaction of the LOCH, thereby releasing the dihydrogen.
In some embodiments, the yarn is passivated to a depth of 20 nm with a metal hydroxide, alternatively with alumina.
In a particular embodiment, the yarn will be contained in a container filled with kerosene or another mineral or organic oil. In this embodiment, the container allows the filament to be unwound without rubbing, the spool of yarn being mounted on its axle on two ball bearings, ball rollings or two magnetically levitated bearings.
In a particular embodiment, the organic liquid for storing the filament will be a hydrogen-carrying organic liquid or LOCH, in its hydrogenated form, such that the liquid is emitted at the same time as the filament into the cyclonic reactor, the reaction of the LAMPHY with the water providing the energy necessary for the dehydrogenation of the hydrogenated LOCH molecule, thus increasing the dihydrogen efficiency.
In some embodiments, a spray of LOCH is injected into the cyclonic reactor at the same time as the LAMPHY so that the exothermic energy of the reaction between LAMPHY and the water allows the release of the hydrogen from the LOCH molecules.
In this embodiment, the yarn exits the container through an orifice equipped with a lip joint, or any other joint capable of maintaining the kerosene in the container as the yarn exits.
In some embodiments, a movable piston capsule filled with argon or CO2, kerosene or LOCH compensates for the volume lost in the container as a result of the yarn leaving the container. The capsule will take the form, for example, of a piston accumulator, one of whose chambers may be left at ambient pressure equilibrium
“Assembled” refers to the juxtaposition of streamlines and “mixing” refers to the mixing of gases.
When the valve itself 85 is positioned in its reception 94, the piston 91, under the action of the spring 90, keeps the valve closed. Similarly, the piston 96, under the action of the spring 101, keeps the other part of the valve closed. When a pressure is applied to the piston 44, the pressure is transmitted to the LAMPHY contained in the container by the movement of the piston 44. The LAMPHY then presses on the piston 91, compressing the spring 90. The piston 91 in turn presses on the piston 96 causing it to retract into the cylinder 100, compressing the spring 1001. The LAMPHY can then flow through the cannulas in the part of the cylinder 99 and of the piston 91. When the pressure at the level of the piston 44 stops, the springs 90 and 101 relax, returning the pistons 91 and 96 to the closed position without letting any product out. This device allows the containers to be placed without the LAMPHY being able to escape.
| Number | Date | Country | Kind |
|---|---|---|---|
| FR2102458 | Mar 2021 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/FR2022/050440 | 3/11/2022 | WO |
