Patent Application
20240375948
The present invention relates to the general technical field of the production of dihydrogen H2, more commonly called “hydrogen”.
In particular, the invention relates to an installation (and an associated method) for producing hydrogen under pressure by a chemical reaction, in particular by decomposition of water under the action of metals or metalloids.
Hydrogen can be used in various applications due to its high energy potential. It can be converted into electricity, heat or motive power depending on the end use.
Not existing naturally, it must be manufactured from a primary energy source, then transported, stored and distributed to the user.
Today, hydrogen can be produced from hydrocarbons by steam reforming of natural gas or by gasification of petroleum residues or coal. A disadvantage of hydrogen production methods by steam reforming is that they involve fossil resources.
Other methods for producing hydrogen, for example by electrolysis or by photocatalysis, have already been proposed. However, a disadvantage of these methods is that the hydrogen is produced under a relatively low pressure—typically comprised between 1 and 30 bars, so that a step of compressing the hydrogen is necessary to allow its loading into storage reservoirs. Moreover, these methods, and in particular electrolysis, are very energy-intensive.
Finally, methods for producing hydrogen using metals that decompose water under the action of an acid or a base are also known. In particular, document US 2003/0143155 discloses a method for producing hydrogen by corrosion of aluminum in water. This method includes the steps consisting of:
A disadvantage of the method according to US 2003/0143155 relates to its significant production cost.
Indeed, when a reaction between aluminum and water is initiated, an impermeable alumina layer forms on the surface of the aluminum, and protects it from corrosion. This has the effect of slowing down or even stopping the corrosion reaction of the aluminum. It is therefore necessary to dissolve this alumina layer using an aqueous solution having a high pH, that is to say a high alkali concentration.
Thus, to implement the method described in document US 2003/0143155, the concentration of sodium hydroxide in the aqueous solution must be high. Therefore, the precipitation of alumina in the bottom of the reaction receptacle mentioned in US 2003/0143155, and the regeneration of sodium hydroxide which follows are limited. This results in consumption of sodium hydroxide during the aluminum corrosion reaction, and thus the need to regularly add sodium hydroxide to the reaction receptacle to maintain the aluminum corrosion reaction, which increases the cost of producing hydrogen from the method according to US 2003/0143155.
A purpose of the present invention is to propose an installation (and its associated method) for producing hydrogen allowing to overcome at least one of the aforementioned disadvantages.
In particular, a purpose of the present invention is to propose an installation configured to produce hydrogen under pressure, treat it, and fill a storage receptacle (such as a bottle) under pressure.
Another purpose of the present invention is to propose a hydrogen production installation to facilitate the management of reaction by-products.
Another purpose of the present invention is to provide an installation and a hydrogen production method allowing to obtain lower hydrogen production costs than those of the installations and methods of the prior art.
To this end, the invention proposes an installation for the production of dihydrogen comprising:
The fact that the reaction enclosure includes:
This arrangement ensures precipitation (for example in the form of alumina) of all the oxidized material produced (for example sodium aluminate), and therefore regeneration of the alkaline aqueous solution before its passage through the reaction chamber.
The device according to the invention thus allows the production of hydrogen without it being necessary to add alkali (such as sodium hydroxide (soda), potassium hydroxide (potash), lithium hydroxide, ammonium hydroxide (ammonia), etc.) during the corrosion reaction of the oxidizable material, which reduces the costs of producing hydrogen.
Preferred but non-limiting aspects of the device according to the invention are the following:
The invention also relates to a method for producing dihydrogen from an installation comprising:
Other advantages and characteristics of the hydrogen production installation and its associated method will emerge better from the description which follows of several variants of execution, given by way of non-limiting examples, from the appended drawings on which:
Different examples of embodiment of the invention will now be described with reference to the figures. In these different figures, the equivalent elements are designated by the same numerical reference.
With reference to
In particular, the installation comprises:
The reaction enclosure 1 allows the implementation of a corrosion reaction of an oxidizable material with the water contained in the alkaline aqueous solution.
The alkaline aqueous solution feed system 2 allows:
The pure water supply system 3 allows to inject pure water into the reaction enclosure 1 at the end of the reaction in order to:
The collection system 4 allows:
The oxidizable material may be selected from a metal—such as magnesium or silicon or aluminum—or a metal alloy—such as an alloy 1050 or an alloy 4032 or an alloy 4043 or an alloy 6060 or an alloy 2017 (or any other metal alloy known to the person skilled in the art). This allows to limit the costs of producing hydrogen. Of course, other oxidizable materials known to the person skilled in the art can also be used. In the following, the invention will be presented with reference to the use of aluminum as an oxidizable material, it being understood that the device and the method according to the invention are not limited to the use of aluminum to produce hydrogen.
“Alkaline aqueous solution” means, in the context of the invention, an aqueous solution whose pH is greater than 7. This alkaline aqueous solution is for example composed of pure water and one (or more) alkali(s).
The alkali(s) may for example be selected from sodium hydroxide (soda), potassium hydroxide (potash), lithium hydroxide, ammonium hydroxide (ammonia).
Advantageously, when the oxidizable material consists of Magnesium or one of its alloys, sodium chloride and/or potassium chloride can be used instead of the alkali (or alkalis).
In the following, the invention will be presented with reference to the use of sodium hydroxide, it being understood that the device and the method according to the invention are not limited to the use of sodium hydroxide to produce hydrogen.
In the context of the invention, “pure water” is defined as water containing water molecules H2O, and possibly traces of mineral salts. Thus, in the context of the invention, distilled water or demineralized water is considered to be pure water, in the same way as osmosis water.
With reference to
It is suitable for withstanding pressures greater than 30 bars, in particular greater than 60 bars. In particular, the reaction enclosure is adapted to withstand pressures greater than 150 bars, preferably greater than 200 bars, and even more preferably greater than 350 bars. Moreover, the reaction enclosure 1 is configured to resist corrosion. Finally, the corrosion reaction of the aluminum 11 being exothermic, the reaction enclosure 1 is configured to withstand temperatures greater than or equal to 200° C. To meet these different constraints, the material constituting the reaction enclosure 1 can be Nickel, or a Nickel alloy.
The corrosion reaction of aluminum 11 with water in the presence of sodium hydroxide induces the production of aluminum oxides and hydroxides. The reaction enclosure 1 is configured to cause the precipitation of these aluminum oxides and hydroxides in the form of aluminates 12, and to contain these aluminates 12.
For this purpose, the reaction enclosure 1 comprises first and second gas-tight chambers C1, C2:
In the embodiment illustrated in
Alternatively, the reaction C1 and settling C2 chambers can be produced in distinct and separate housings, said housings being connected via pipelines to allow the circulation of the reaction fluid between the reaction C1 and settling C2 chambers. This allows in particular to use reaction C1 and settling C2 chambers of different shapes and dimensions. This also allows to reduce the height of the reaction enclosure 1.
Advantageously, the reaction chamber C1 may comprise a heat accumulator 14 extending over the side wall(s) of the reaction chamber C1. This allows to limit the risks of an increase in temperature in the reaction enclosure 1 beyond 250° C.
Indeed, such a heat accumulator 14 is capable of:
Thus, the heat accumulator 14 allows:
In certain variant embodiments, the heat accumulator 14 may comprise:
PCM is a material capable of changing physical state (solid/liquid) within a restricted temperature range (for example between 200° C. and 250° C.). Thus, PCM has the particularity of going from the liquid state to the solid state at a temperature close to 200° C. The solidification reaction (that is to say transition from the liquid state) to the solid state is exothermic. The liquefaction reaction (transition from the solid state to the liquid state) is endothermic. The integration of such a heat accumulator 14 therefore allows better control of the temperature inside the reaction enclosure 1.
The reaction enclosure 1 also comprises a stirring unit to promote the circulation of the reaction fluid between the reaction chamber C1 and the settling chamber C2.
In the embodiment illustrated in
For this purpose, the reaction chamber C1 comprises a first tubular access member disposed in its upper part (that is to say closer to the cover of the housing than the grid of the housing), and the settling chamber C2 comprises a second tubular access member disposed in its upper part (that is to say closer to the grid of the housing than to the bottom of the housing). The centrifugal pump P1 is connected to the reaction C1 and settling C2 chambers so as to:
Alternatively, the stirring unit may consist of a propeller including a shaft and two (or four) blades at one end of the shaft, the other end of the shaft being connected to a motor to induce the rotation of the propeller shaft and blades. In this case, the propeller is directly immersed in the housing, between the reaction C1 and settling C2 chambers.
Advantageously, the dimensions of the reaction C1 and settling C2 chambers as well as the characteristics of the stirring unit are selected so that:
The fact that, in the reaction chamber C1, the circulation speed of the reaction fluid is greater than or equal to 5 cm/s (preferably greater than or equal to 6 cm/s) allows to promote the evacuation of the by-products of the corrosion reaction of the aluminum outside the reaction chamber (and therefore limits the risk of slowing down the corrosion reaction due to the alumina).
The fact that, in the settling chamber C2, the circulation speed of the reaction fluid is less than or equal to 4 cm/s (preferably less than or equal to 3 cm/s) allows:
To obtain different circulation speeds between the reaction chamber and the settling chamber (and in particular speeds of the order of 6 cm/s in the reaction chamber and 3 cm/s in the settling chamber), the diameter of the reaction chamber can be reduced relative to the diameter of the settling chamber (in the case of cylindrical chambers).
This reduction in diameter in the reaction chamber can be obtained:
In certain embodiments, the settling chamber C2 may comprise a cyclone (or hydrocyclone) separation system to promote the separation of the reaction fluid from the solid particles it contains. Such a cyclone separation system (not shown) is known to the person skilled in the art and will not be described in more detail below.
Optionally, a cooling unit can be mounted on the walls of the settling chamber C2 to reduce the temperature of the reaction fluid. This allows to promote the precipitation of aluminum oxides and hydroxides contained in the reaction fluid in the form of aluminates 12.
The reaction enclosure 1 comprises an oxidizable material support for carrying the oxidizable material. In the embodiment illustrated in
Advantageously, the reaction enclosure may comprise a filling sensor 16 placed between the reaction chamber C1 and the collection system 4. The filling sensor 16 allows to detect the presence of alkaline aqueous solution. Its positioning allows to indicate, to the control unit, the instant at which the maximum volume of alkaline aqueous solution that the reaction enclosure 1 can contain is reached, in particular when filling the reaction enclosure 1 with the alkaline aqueous solution 21, as will be described in more detail below.
With reference to
The alkaline aqueous solution 21 may comprise water mixed with sodium hydroxide (NaOH) or potassium hydroxide (KOH) with a concentration between 0.5% and 20%.
The feed system 2 comprises a tank 22 adapted to contain the alkaline aqueous solution 21. This tank 22 can have different shapes and be made of different materials capable of resisting corrosion (such as Nickel or a Nickel alloy).
The tank 22 is brought to atmospheric pressure via a vent opening 23 formed in the upper wall of the tank 22. This opening 23 allows to avoid the formation of a depression in the tank 22 when the alkaline aqueous solution 21 is injected into the reaction enclosure 1 at the start of the reaction. The opening 23 also allows the filling of the tank 22 with the alkaline aqueous solution, as will be described in more detail below.
The feed system 2 also comprises one (or more) conduit(s) 24 allowing fluid communication between the tank 22 and the reaction enclosure 1. Each conduit 24 can be associated with an electrically controllable circulation valve 25 (that is to say solenoid valve) to authorize (when the circulation valve 25 is in an open state) or prevent (when the circulation valve 25 is in a closed state) the passage of the alkaline aqueous solution 21 between the tank 22 and the reaction enclosure 1. This ensures:
In the embodiment illustrated in
With reference to
Alternatively, the feed system 2 may include a pump—for example of the peristaltic pump or roller pump type—for circulating the alkaline aqueous solution 21 between the tank 22 and the reaction enclosure 1.
Of course, the feed system 2 may comprise other components known to the person skilled in the art such as:
With reference to
The supply system 3 comprises a tank 32 configured to contain the pure water 31. This tank 32 can have different shapes and be made of different materials such as steel, aluminum or plastic.
The tank 32 is brought to atmospheric pressure via an vent lumen 33. This lumen 33 allows to avoid the formation of a depression in the tank 32 when the pure water 31 is injected into the reaction enclosure 1, or of an overpressure in the tank when pure water is introduced therein.
The supply system 3 also comprises one (or more) pipe(s) 34 allowing fluid communication of the tank 32 with the reaction enclosure 1, each pipe 34 being associated with an electrically controllable valve 35 to authorize or not the passage of pure water 31 through said pipe 34.
In the embodiment illustrated in
Optionally, the supply system 3 can also include a high pressure transfer pump 36 to ensure the movement of pure water 31 between the tank 32 and the reaction enclosure 1.
Injecting pure water 31 into the reaction enclosure 1 allows:
Advantageously, the supply system 3 can comprise a degassing valve 37 to allow the pressure inside the reaction enclosure 1 to be gradually reduced at the end of the reaction, and in particular to return the installation to atmospheric pressure when all the oxidizable material has been consumed.
Of course, the supply system 3 may comprise other components known to the person skilled in the art such as:
With reference to
In particular, the collection system 4 is adapted to:
For filtering the gases generated by the corrosion reaction of the aluminum 11, the collection system comprises a heat exchanger 41 to cool the gases generated in order to extract the water vapor.
The heat exchanger 41 is configured to withstand high pressures (pressures greater than 30 bars, in particular greater than 60 bars, preferably greater than 150 bars, more preferably greater than 250 bars and even more preferably greater than 350 bars), and high temperatures (temperatures greater than or equal to 200° C., in particular greater than or equal to 250° C.). The heat exchanger 41 is for example of the air-cooled type.
For example, the heat exchanger 41 may comprise:
Alternatively, the heat exchanger 41 can be of the heat transfer fluid cooling type.
The collection system 4 also comprises a temperature sensor 42 in communication with the control unit (not shown) of the installation, the control unit activating the heat exchanger 41 when the temperature measured by the temperature sensor 42 is greater than a predefined threshold value (for example 50° C.).
The heat exchanger 41 allows to condense the water vapor contained in the gases leaving the reaction enclosure 1 to form pure liquid water. This pure liquid water (or condensate) is separated from the hydrogen using a condensate separator 48 placed at the outlet of the heat exchanger 41.
During the corrosion reaction, the pure liquid water is reintroduced into the reaction chamber C1 of the reaction enclosure 1. At the end of the corrosion reaction, the pure water is reintroduced into the tank 32 of the supply system 3.
For this purpose, the heat exchanger 41 is in fluid communication—via one (or more) pipeline(s)—with the reaction enclosure 1 on the one hand, and with the supply system 3 on the other hand, one (or more) controlled orientation valve(s) (for example one (or more) solenoid valve(s)) arranged along the pipeline(s) allowing to direct the circulation of the condensed water to the reaction enclosure 1 or to the supply system 3.
Optionally, the collection system 4 may comprise a liquid sensor 43 and a controlled safety valve 44 downstream of the heat exchanger 41. The liquid sensor 43 and the safety valve 44 are configured to communicate with the control unit.
In particular:
The presence of a liquid sensor 43 associated with a safety valve 44 the opening and closing of which are controlled by the controller allows to limit the risks of degradation of the storage receptacle with corrosive liquid.
To allow the circulation of gases between the heat exchanger 41 and the storage receptacle 5, the collection system 4 comprises a gas circulation conduit 45 connected to the heat exchanger 41 on the one hand and to the storage receptacle 5 on the other hand.
However, before being stored in the storage receptacle 5, the hydrogen must be treated to have a given purity and/or a given humidity level which depend on the technical specifications of the storage receptacle 5 and/or the intended application. This is why the collection system 4 comprises a gas purifier 46 mounted along the gas circulation conduit 45 between the heat exchanger 41 and the storage receptacle 5. This purifier 46 can contain a desiccant product (silica gel type, CaO, CaCl2 or others), and/or an activated carbon, and/or a particle filter, and/or a hydrophobic membrane, and/or a palladium membrane, etc.
Advantageously, the collection system 4 may include a discharger 47 (or pressure reducer) mounted along the gas circulation conduit 45. This discharger 47 allows to regulate the pressure of the gas in the collection system 4 in order to make it correspond to the desired pressure for the storage receptacle 5 (for example storage of hydrogen at a pressure of 150 bars, or 200 bars, or 350 bars, etc.).
Finally, the collection system 4 may include an isolation valve 48 downstream of the purifier 46 to (manually or automatically) open/close the passage between the purifier 46 and the storage receptacle 5. This allows to close the gas circulation conduit 45 in order to disconnect the storage receptacle when it is full and replace it with an empty storage receptacle.
The principle of operation of the hydrogen production installation will now be described with reference to
A first phase of the hydrogen production method relates to the preparation of the installation, and in particular its loading for the implementation of the corrosion reaction.
When the installation has not yet been used, a first step in the preparation phase relates to the formulation of the alkaline aqueous solution. For this purpose:
Pure water and sodium hydroxide are mixed to form the alkaline aqueous solution.
When implementing the formulation step, the first and second circulation valves 25a, 25b are in a closed state to maintain the alkaline aqueous solution in the tank 22.
Advantageously, the formulation step is only implemented once during the first use of the installation, the alkaline aqueous solution being reusable at the end of the corrosion reaction.
The preparation phase also comprises a step of supplying pure water in the tank 32 of the supply system.
This step of supplying pure water may consist of:
Whether it is the first filling or an upgrade, pure water can be introduced into the supply system at the lumen 33 formed in the upper wall of the tank 32.
The preparation phase also comprises a step of loading the enclosure with the oxidizable material (aluminum, etc.) necessary for the formation of hydrogen.
The oxidizable material may have the shape of a block. It is introduced into the reaction chamber C1 and placed on the support of the reaction enclosure 1 to allow it to be maintained in position during the corrosion reaction carried out subsequently.
With reference to
To initiate the corrosion reaction, the different reagents are mixed in the reaction enclosure 1 which contains the oxidizable material.
Particularly during the start-up step, the reaction enclosure 1 is filled with the alkaline aqueous solution 21. For this purpose, the second circulation valve 25b is switched to a passing state to allow the circulation of the alkaline aqueous solution 21 from the tank 22 towards the reaction enclosure 1. The movement of the alkaline aqueous solution 21 can be ensured by any means known to the person skilled in the art (gravity, activation of a pump, etc.). In the embodiment illustrated in
Once the reaction enclosure is completely filled with the alkaline aqueous solution, the corrosion reaction starts and hydrogen is produced: the isolation valve 48 is opened (either manually or automatically by the control unit) to allow the circulation of the hydrogen produced between the collection system 4 and the storage receptacle 5.
The corrosion reaction of the oxidizable material begins: hydrogen is continuously generated, the reaction solution circulates in the reaction enclosure 1 between the reaction C1 and settling C2 chambers.
The pressure and temperature in the reaction enclosure 1 gradually increase. When the pressure in the reaction enclosure 1 (and in the gas collection system 4) reaches the desired pressure for the storage receptacle 5 (for example 150 bars, 200 bars, 250 bars, 300 bars or 350 bars), the discharger 47 opens and allows the hydrogen to circulate in the gas purifier 46 and then in the storage receptacle 5.
At the outlet of the gas purifier 46, the hydrogen is dry:
During the corrosion reaction of aluminum 11 with the alkaline aqueous solution 21, hydrogen, aluminum oxides and aluminum hydroxides are produced in the reaction chamber C1. The hydrogen escapes to the gas collection system 4, while the aluminum oxides and hydroxides are transported in the reaction fluid to the settling chamber C2 where they precipitate in the form of aluminates 12. The hydrogen which is evacuated towards the collection system 4 is saturated with water vapor and has a very high temperature. As it passes through the heat exchanger, the hydrogen is cooled (to approximately 60° C.) and the excess water vapor it contains is condensed into pure liquid water. This pure liquid water is reintroduced into the reaction chamber C1 of the reaction enclosure 1.
At the end of the reaction, and as illustrated in
As the corrosion reaction consumes water molecules, the level of alkaline aqueous solution contained in the reaction enclosure 1 is lower at the end of the reaction than at the start of the reaction.
As a result, a gas pocket 17—called “gaseous sky”—at high pressure containing approximately 30% of hydrogen produced during the reaction is present in the reaction chamber C1.
In order to improve the yield of the reaction, the method can comprise a sub-step consisting of recovering the hydrogen contained in this gaseous sky.
A first solution for recovering the hydrogen contained in the gaseous sky 17 consists of injecting pure water into the reaction enclosure from the supply system 3. For this purpose, the transfer pump 36 is activated and the outlet valve 35b is switched to a passing state to allow the transfer of pure water at high pressure from the tank 32 to the settling chamber C2 of the reaction enclosure 1. This induces the movement of the gaseous sky towards the gas collection system 4 for the recovery of the hydrogen contained therein.
A second solution for recovering part of the hydrogen contained in the gaseous sky 17 consists of:
This second solution allows to recover approximately 75% of the hydrogen contained in the gaseous sky 17.
A sub-step of restoring the installation to operating condition can also be implemented.
This restoration sub-step comprises
For cooling and bringing the installation to atmospheric pressure, the inlet valve 35a of the supply system 3 is switched to a state allowing the circulation of pure water between the collection system 4 and the supply system 3. Thus, from this switching of the inlet valve 35a, all the condensed water vapor (forming pure water) by the heat exchanger is routed to the tank 32. Moreover, the degassing valve 37 is opened gradually to allow the gases to escape through the tank 32 which is at atmospheric pressure. This allows to reduce the pressure inside the reaction enclosure on the one hand and the collection system on the other hand. After an initial loss of pressure, the reaction solution begins to boil, actively evaporating some water and lowering the temperature. The water vapors are condensed in the heat exchanger 41 of the collection system 4 and the condensate thus obtained is reintroduced into the tank 32 of the supply system 3.
To purge the installation, the control unit activates the first circulation valve 25a to switch it into a passing state in order to allow the passage of the alkaline aqueous solution from the reaction enclosure 1 to the tank 22. The circulation of the alkaline aqueous solution between the chambers C1, C2 and the tank 22 can be provided by gravity or obtained by motorized action (using a pump). The alkaline aqueous solution thus purged can be reused subsequently to carry out a new corrosion reaction. This allows to limit the amount of soda used for the generation of hydrogen.
For rinsing the by-products, pure water from the supply system 3 can be poured into the settling chamber C1. This allows to rid the by-products 12 of any soda deposits present on their surfaces. The rinsing water is recovered in the tank 22 of the feed system 2. Here again, this rinsing allows to limit the amount of soda used for the generation of hydrogen (in addition to cleaning the reaction by-products).
The lower part of the settling chamber is then detached to evacuate the solid by-products of the reaction.
The installation described above allows to generate hydrogen by:
This installation also allows the generation of hydrogen at high pressure (up to 350 bars).
The reader will have understood that numerous modifications can be made to the invention described above without materially departing from the new teachings and advantages described here.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2304739 | May 2023 | FR | national |
