Apparatus and method for generating gaseous hydrogen

Abstract

The present invention relates to an apparatus (1) for the electrochemical generation of gaseous hydrogen starting from an aqueous solution comprising at least one electrolyte, and the related method. The apparatus (1) comprises: - at least one anode (2) arranged, in use, in said aqueous solution; - at least one cathode (3) electrically connected to said anode (2) to form an electrochemical cell, said cathode (3) being arranged, in use, in said aqueous solution, wherein said anode (2) is made of a material comprising at least 90% metallic magnesium.

Description

Apparatus and method for generating gaseous hydrogenScope of the invention

[0001] The present invention relates to an apparatus for the electrochemical generation of gaseous hydrogen .

[0002] In particular, said apparatus for the electrochemical generation of gaseous hydrogen finds advantageous application using, as a starting reagent , an aqueous solution comprising at least one electrolyte .

[0003] For illustrative and non-limiting purposes only, an electrolyte is any chemical species that generates ionic species in aqueous solution .

[0004] The present invention also relates to a method for the electrochemical generation of gaseous hydrogen .

[0005] In particular, said method for the electrochemical generation of gaseous hydrogen finds advantageous application using, as a starting reagent , an aqueous solution comprising at least one electrolyte .Brief outline of the prior art

[0006] As is well known, in recent years , technological development aimed at generating gaseous hydrogen has been widely pursued by a large number of public and private entities in all industrial countries , as hydrogen is generally regarded in scienti fic l iterature as a useful means for the ecological transition of industrial societies .

[0007] An example of the application of gaseous hydrogenfor the ecological transition is in the form of the fuel of the future, due to its abundant presence in nature in the form of water. Furthermore, the combustion of this fuel would have little or no impact in terms of greenhouse gas emissions (particularly carbon dioxide) , as combustion in the presence of oxygen generates water vapour.

[0008] For this reason, the design and implementation of systems for the generation of gaseous hydrogen is constant.

[0009] For example, processes for generating hydrogen are known that can utilise mainly three sources: (1) fossil fuels, (2) biomass and (3) water.

[0010] Current conventional ways of producing hydrogen from fossil fuels involve the use of natural gas, oil or methanol, for example.[Oil] Current conventional ways of producing hydrogen from water are, for example, by electrolysis of water.

[0012] Of the three ways of generating gaseous hydrogen, steam reforming of natural gas into hydrogen is widely used in industrial hydrogen production, which has the lowest cost of hydrogen production, and this method has the advantages of a simple production process and a high hydrogen yield, but has a significant level of C02 emission.

[0013] Hydrogen from oil is obtained from the product of cracking oil, but it is a more expensive process than reforming natural gas.

[0014] Hydrogen from methanol is produced by steam reforming methanol, which is more expensive than gaseous hydrogen itself (thus, it is not a cost-effective process) .

[0015] Hydrogen production from biomass mainly consists of using biomass for energy production or fermenting biomassto produce hydrogen. This production process does not allow for the high productivity required at industrial level.

[0016] The preparation of hydrogen by electrolysis of water is also widely used. By passing a direct current through an electrolyte-filled cell, water molecules can be electrochemically reacted on the electrodes and decomposed to form hydrogen and oxygen.

[0017] Although the process is simple and the purity of the hydrogen produced is high, the electrolysis process consumes a large amount of electricity and therefore has a high production cost.

[0018] To overcome the high production cost, processes have been developed for the generation of gaseous hydrogen through the electrolysis of water in which the current required for the process is obtained by capturing solar radiation using photoelectrodes. However, these photoelectrochemical processes are still at the laboratory research stage and can only be used for the preparation of limited quantities of hydrogen.

[0019] These hydrogen generation processes therefore have several drawbacks.

[0020] A first drawback is the fact that some of these processes are not cost-effective in view of the market value of gaseous hydrogen.

[0021] A second drawback is that some of these processes have low hydrogen productivity, productivity being the amount of gaseous hydrogen generated per unit of time.

[0022] A third drawback is that some of these processes have a high environmental impact, mainly due to significant C02 emissions.Summary of the invention

[0023] It is an object of the present invention to provide an apparatus for the electrochemical generation of gaseous hydrogen, preferably starting from an aqueous solution comprising at least one electrolyte, which enables an important level of cost-effectiveness, high productivity and which has a reduced environmental impact.

[0024] In addition, the aim of the present invention is to provide a method for the electrochemical generation of gaseous hydrogen, preferably starting from an aqueous solution comprising at least one electrolyte, that is cost- effective, highly productive and has a low environmental impact .

[0025] According to the present invention, an apparatus 1 is provided for the electrochemical generation of gaseous hydrogen, as defined in claim 1.

[0026] In particular, said apparatus for the electrochemical generation of gaseous hydrogen finds advantageous application using, as a starting reagent, an aqueous solution comprising at least one electrolyte.

[0027] For illustrative and non-limiting purposes only, an electrolyte is any chemical species that generates ionic species in aqueous solution.

[0028] Preferably, said apparatus 1 comprises at least one anode 2.

[0029] Preferably, said anode 2 is arranged, in use, in said aqueous solution.

[0030] Preferably, said apparatus 1 comprises at least one cathode 3 electrically connected to said anode 2 to form an electrochemical cell.

[0031] Preferably, said electrochemical cell consists of a galvanic cell.

[0032] Preferably, said cathode 3 is arranged, in use, in said aqueous solution.

[0033] Preferably, said anode 2 is made of a material comprising metallic magnesium.

[0034] This solution solves all of the aforementioned technical drawbacks.

[0035] In particular, the presence of said anode 2 made of a material comprising metallic magnesium ensures an important level of cost-effectiveness, high productivity and reduced environmental impact.

[0036] According to the present invention, a method is also provided for the electrochemical generation of gaseous hydrogen as defined in claim 1.

[0037] In particular, said method for the electrochemical generation of gaseous hydrogen finds advantageous application using, as a starting reagent, an aqueous solution comprising at least one electrolyte.

[0038] For illustrative and non-limiting purposes only, an electrolyte is any chemical species that generates ionic species in aqueous solution.

[0039] Preferably, said method comprises a step of immersing at least one anode 2 in said aqueous solution.

[0040] Preferably, said method comprises a step of immersing at least one cathode 3, electrically connected to said anode 2 to form an electrochemical cell, in said aqueous solution .

[0041] Preferably, said electrochemical cell consists of a galvanic cell.

[0042] Preferably, said anode 2 is made of a material comprising metallic magnesium.

[0043] This solution solves all of the aforementioned technical drawbacks.

[0044] In particular, the presence of said anode 2 made of a material comprising metallic magnesium ensures an important level of cost-effectiveness, high productivity and reduced environmental impact.Brief description of the drawings

[0045] For a better understanding of the present invention, a preferred embodiment is now described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0046] Figure 1 shows a schematic view of an apparatus for generating gaseous hydrogen, according to an embodiment of the invention;

[0047] Figure 2 shows a schematic view of an apparatus for generating gaseous hydrogen, according to an embodiment of the invention.

[0048] Figures 3 to 6 show a preferred solution of the invention with the cathode in the form of a container containing the aqueous solution and the anode connected to a wall of said container.Description of some preferred embodiments

[0049] Referring to Figure 1 and Figure 2, the apparatus 1 for the electrochemical generation of gaseous hydrogen finds advantageous application using, as a starting reagent, an aqueous solution comprising at least one electrolyte.

[0050] For illustrative and non-limiting purposes only,an electrolyte is any chemical species that generates ionic species in aqueous solution.

[0051] Preferably, said apparatus 1 comprises at least one anode 2.

[0052] Preferably, said anode 2 is arranged, in use, in said aqueous solution.

[0053] Preferably, said apparatus 1 comprises at least one cathode 3 electrically connected to said anode 2 to form an electrochemical cell.

[0054] Preferably, said electrochemical cell consists of a galvanic cell.

[0055] Preferably, said cathode 3 is arranged, in use, in said aqueous solution.

[0056] According to an embodiment, as illustrated in Figure 1, said anode 2 and said cathode 3 are electrically connected by simple contact (e.g. by deposition of one material on the other or by embedding one material in the other) between the respective surfaces.

[0057] According to an alternative embodiment illustrated in Figure 2, said anode 2 and said cathode 3 are electrically connected via an electrical conductor of any known type (e.g. a wire) .

[0058] Preferably, said anode 2 is made of a material comprising metallic magnesium.

[0059] According to an alternative embodiment, said apparatus 1 involves the use of a metal container containing said electrolyte solution as the cathode 3, provided it is made of a material with a less electronegative electrochemical potential than the anode 2. The contact between anode 2 and cathode 3 must be made by means of anelectrical conductor; the electrical conductor need not necessarily be a cable, but a pin (e.g. one or more pins) may also be used, provided it is made of a conducting material. This is in order to form an electrochemical cell in said aqueous solution.

[0060] These characteristics derive from the experimental tests carried out by the Applicant, in which the Applicant tried out different alternative solutions, in order to find the solution that best guaranteed a significant level of cost-effectiveness, high productivity and reduced environmental impact.

[0061] In particular, the presence of said anode 2 made of a material comprising metallic magnesium ensures an important level of cost-effectiveness, high productivity and reduced environmental impact.

[0062] In detail, in this description, the term cathode refers to the electrode on which the reduction reaction takes place, while the term anode refers to the electrode on which the oxidation reaction takes place.

[0063] In a galvanic cell, i.e. a preferred form of electrochemical cell according to the present invention, the electrode consisting of the most electronegative material will yield electrons and thus form the anode.

[0064] According to a preferred embodiment of the present invention, the galvanic cell comprises at least one electrode made of a material comprising metallic magnesium and at least one electrode made of any material, preferably metallic, which is less electronegative than the material of which the material comprising metallic magnesium is made.

[0065] Thus, the electrode made of a material comprisingmetallic magnesium acts as the anode 2 while the electrode made of any preferably metallic material that is less electronegative than the material comprising metallic magnesium acts as the cathode 3. In detail, since metallic magnesium is more electronegative than the other chemical species (e.g. metal) , it gives up electrons and thus acts as the anode 2 while the other electrode (made of a different material) acts as the cathode 3.

[0066] The oxidation reaction occurring at the anode 2 generates magnesium ions, according to the equation below:Mg - 2e~ Mg2+while the reduction reaction occurring at the cathode 3 generates gaseous hydrogen and hydroxide ions, according to the following equation:2H2O + 2e~ H2+ 20H

[0067] The total hydrolysis reaction by means of said electrochemical cell (preferably galvanic) is given by the following equation:Mg + 2H2O Mg(OH)2+ H2

[0068] In particular, said anode 2 as described is a sacrificial anode, as the metallic magnesium of which it ismade is consumed by its oxidation, generating magnesium ions that combine with the hydroxide ions generated by the water reduction reaction occurring at the cathode. This combination generates magnesium hydroxide as a co-product of hydrogen .

[0069] The Applicant noted that by means of this electrochemical cell, it is possible to generate large quantities (by way of non-limiting example more than 900 litres) of gaseous hydrogen using a material comprising metallic magnesium in quantities of 1 kg in weight. This highlights significant cost-effectiveness for said electrochemical cell (due to the fact that metallic magnesium is inexpensive) , high gaseous hydrogen productivity and reduced environmental impact (since, in particular, there are no greenhouse or harmful gas emissions) .

[0070] According to a further aspect of the invention, as illustrated in Figure 1, said anode 2 and said cathode 3 are configured according to a single body 4 whose matrix comprises said anode 2 and said cathode 3.

[0071] In other words, as already mentioned, said anode 2 and said cathode 3 can be electrically connected by simple contact between their respective surfaces since they form a single body 4.

[0072] Said single body 4 is made, for example, by deposition of the material comprising metallic magnesium on the other (or vice versa) or by incorporation of the material comprising metallic magnesium in the other (or vice versa) , so that the matrix of the single body 4 comprises said anode 2 and said cathode 3.

[0073] According to this configuration, the said anodicand cathodic reactions occur on the surface of the single body 4 at areas of the matrix of the single body 4 in which the material comprising metallic magnesium and the other less electronegative material than the material comprising metallic magnesium is present at least punctually, respectively .

[0074] In detail, metallic magnesium and the other less electronegative material constitute distinct phases within the matrix of the single body 4.

[0075] Due to the different electrochemical corrosion potentials of these phases, a galvanic cell is in fact generated between the interfaces of the phases of said matrix. During the hydrolysis reaction, the surface of the magnesium phase acts as an anode and loses electrons to form magnesium ions, while the surface of the phase of the other less electronegative material acts as a cathode and the water molecules gain electrons by releasing gaseous hydrogen.

[0076] The hydrolysis reaction through said single body 4 is generally preferentially initiated at said interfaces and gradually diffuses into the matrix of the single body 4.

[0077] This configuration allows for a small footprint of apparatus 1 and makes it even simpler.

[0078] According to a further aspect of the invention, said material comprising metallic magnesium for said anode 2 consists of a metal alloy comprising magnesium.

[0079] According to a preferred embodiment, said metal alloy comprises magnesium.

[0080] Even more preferably, said metal alloy comprises magnesium and at least one additional metal.

[0081] Said metal is, for example, selected from the groupconsisting of : aluminium, silicon, manganese , tin, copper .

[0082] Even more preferably, said metal alloy consists of the commercially available AZ 63HP, which comprises magnesium, aluminium and silicon .

[0083] This metal alloy AZ 63HP was identi fied by the Applicant on the basis of experimental tests aimed at selecting a metal alloy with good electrical conductivity as well as high elasticity, which also implies a better and easier processability of the alloy itsel f for the manufacture of the anode 2 .

[0084] According to a further aspect of the invention, said anode 2 and / or said cathode 3 are electrically connected by means of an electrical circuit 5 configured to impart a direct or alternating current to said anode 2 and said cathode 3 increas ing the generation of gaseous hydrogen per unit time .

[0085] In other words , as described above and as illustrated in Figure 2 , said anode 2 and said cathode 3 can be electrically connected by means of an electrical conductor .

[0086] Said electrical conductor may be part of an electrical circuit 5 configured to impart a direct or alternating current to said anode 2 and said cathode 3 . This imparted current leads to an increase in the speed of reactions at the anode 2 and cathode 3 , which results in an increase in the generation of gaseous hydrogen per unit time .

[0087] This solution was configured by the Applicant to further increase the productivity of gaseous hydrogen, cost- ef fectively and with reduced environmental impact .

[0088] According to a further aspect of the invention,said electrical circuit 5 imparts said direct or alternating current to said anode 2 and said cathode 3 by means of a voltage, for example, in the range of 1 V to 10 V.

[0089] This solution was configured by the Applicant to increase the productivity of gaseous hydrogen in an entirely cost-effective manner, since for the voltage comprised in this range, the energy cost is entirely negligible compared to the higher productivity of gaseous hydrogen produced (i.e. the higher quantity of gaseous hydrogen produced per unit of time has an economic value that is higher than the energy used to obtain it) . In other words, for voltages above or below the range identified by the Applicant, the productivity of gaseous hydrogen does not increase or the productivity / energy cost ratio is lower than that ratio for voltages comprised within that range.

[0090] According to a further aspect of the invention, said apparatus 1 comprises a device 6 configured to store electrochemically generated gaseous hydrogen.

[0091] In detail, said device 6 comprises means for collecting the gaseous hydrogen generated at the electrochemical cell and means for storing / accumulating the collected gaseous hydrogen (e.g., a vessel / container or a tank) . These collection means and these storage / accumulation means are well known from the state of the art for the collection and storage / accumulation of gases in general, but their advantageous application to the said electrochemical cell allows the gaseous hydrogen generated (i.e., the product of interest generated by the electrochemical cell) to be handled appropriately and if necessary, maximising productivity as inefficiencies due to gaseous hydrogen leaksare avoided.

[0092] According to a preferred embodiment, said device 6 further comprises means of conveying gaseous hydrogen (e.g., a compressor) , arranged between said collection means and said storage / accumulation means.

[0093] Said conveying means are configured to convey said gaseous hydrogen from said collection means to said storage / accumulation means.

[0094] These conveying means are well known from the state of the art for conveying gases in general, but their advantageous application to the said electrochemical cell allows the gaseous hydrogen generated (i.e., the product of interest generated by the electrochemical cell) to be conveyed in a suitable manner and if necessary, maximising productivity as inefficiencies due to gas leaks are avoided.

[0095] According to a further aspect of the invention, said aqueous solution comprising at least one electrolyte consists of an aqueous solution comprising sodium chloride.

[0096] Preferably, said aqueous solution comprising sodium chloride may comprise other salts that increase the conductivity of the electrolyte.

[0097] In particular, the use of an aqueous solution of sodium chloride, i.e. salt water, as the starting solution for the generation of gaseous hydrogen by electrochemical means, makes it possible to further contain the costs involved in the production of hydrogen, and to achieve reduced environmental impact for said apparatus 1, since water and salt are abundant components in nature and are low in cost.

[0098] According to a preferred embodiment, the aqueoussolution of sodium chloride consists of seawater.

[0099] In particular, the use of seawater as the starting solution for the generation of gaseous hydrogen by electrochemical means makes it possible to further contain the costs involved in the production of hydrogen, and to achieve reduced environmental impact for said apparatus 1, since seawater is abundant in nature and has little or no cost .

[0100] According to a further aspect of the invention, said aqueous solution comprising sodium chloride may have a sodium chloride concentration, e.g. preferably comprised in the range of 25 g / 1 - 40 g / 1.

[0101] This range of concentrations of said aqueous solution in sodium chloride was identified by the Applicant as the optimal range for the generation of gaseous hydrogen. In particular, for higher or lower concentrations, said apparatus 1 as described does not have superior gaseous hydrogen productivity or in any case there is no preference in terms of cost-effectiveness.

[0102] According to a further aspect of the invention, said anode 2 has a size and / or conformation configured to generate a desired amount of gaseous hydrogen per unit time.

[0103] These characteristics derive from the experimental tests carried out by the Applicant, in which the Applicant tried out different alternative solutions in order to find the solution that best ensured high productivity.

[0104] In detail, a variety of shapes and sizes can be used. Tests carried out by the Applicant have shown that a parallelepiped shape in which the thickness of the anode 2 has a minimum ratio of 1 / 10 to its length ensures optimumproductivity in the generation of gaseous hydrogen.

[0105] However, it also operates with different forms and / or ratios.

[0106] According to a further aspect of the invention, the method for the electrochemical generation of gaseous hydrogen is advantageously applied using, as a starting reagent, an aqueous solution comprising at least one electrolyte .

[0107] For illustrative and non-limiting purposes only, an electrolyte is any chemical species that generates ionic species in aqueous solution.

[0108] Preferably, said method comprises a step of immersing at least one anode 2 in said aqueous solution.

[0109] Preferably, said method comprises a step of immersing at least one cathode 3, electrically connected to said anode 2 to form an electrochemical cell, in said aqueous solution .

[0110] According to an alternative embodiment, said method involves the use of a metal container containing said electrolyte solution as the cathode 3, provided it is made of a material with a less electronegative electrochemical potential than the anode 2. The contact between anode 2 and cathode 3 must be made by means of an electrical conductor; the electrical conductor need not necessarily be a cable, but a pin may also be used, provided it is made of a conducting material. This is in order to form an electrochemical cell in said aqueous solution.

[0111] Preferably, said electrochemical cell consists of a galvanic cell.

[0112] According to an embodiment, as illustrated inFigure 1, said anode 2 and said cathode 3 are electrically connected by simple contact (e.g. by deposition of one material on the other or by embedding one material in the other) between the respective surfaces.

[0113] According to an alternative embodiment illustrated in Figure 2, said anode 2 and said cathode 3 are electrically connected via an electrical conductor of any known type (e.g. a wire) .

[0114] Preferably, said anode 2 is made of a material comprising metallic magnesium.

[0115] These characteristics derive from the experimental tests carried out by the Applicant, in which the Applicant tried out different alternative solutions, in order to find the solution that best guaranteed a significant level of cost-effectiveness, high productivity and reduced environmental impact.

[0116] In particular, the presence of said anode 2 made of a material comprising metallic magnesium ensures an important level of cost-effectiveness, high productivity and reduced environmental impact.

[0117] In detail, in this description, the term cathode refers to the electrode on which the reduction reaction takes place, while the term anode refers to the electrode on which the oxidation reaction takes place.

[0118] In a galvanic cell, i.e. a preferred form of electrochemical cell according to the present invention, the electrode consisting of the most electronegative material will yield electrons and thus form the anode.

[0119] According to a preferred embodiment of the present invention, the galvanic cell comprises at least one electrodemade of a material comprising metallic magnesium and at least one electrode made of any material, preferably metallic, which is less electronegative than the material of which the material comprising metallic magnesium is made.

[0120] Thus, the electrode made of a material comprising metallic magnesium acts as the anode 2 while the electrode made of any preferably metallic material that is less electronegative than the material comprising metallic magnesium acts as the cathode 3. In detail, since metallic magnesium is more electronegative than the other chemical species (e.g. metal) , it gives up electrons and thus acts as the anode 2 while the other electrode (made of a different material) acts as the cathode 3.

[0121] The oxidation reaction occurring at the anode 2 generates magnesium ions, according to the equation below:Mg - 2e~ Mg2+while the reduction reaction occurring at the cathode 3 generates gaseous hydrogen and hydroxide ions, according to the following equation:2H2O + 2e~ H2+ 20H

[0122] The total hydrolysis reaction by means of said electrochemical cell (preferably galvanic) is given by the following equation:Mg + 2H2O Mg ( OH)2+ H2

[0123] In particular, said anode 2 as described is a sacri ficial anode , as the metallic magnesium of which it is made is consumed by its oxidation, generating magnesium ions that combine with the hydroxide ions generated by the water reduction reaction occurring at the cathode . This combination generates magnesium hydroxide as a co-product of hydrogen .

[0124] The Applicant noted that by means of this electrochemical cell , it is possible to generate more than 900 litres of gaseous hydrogen using a material comprising metallic magnesium in quantities of 1 kg in weight . This highlights signi ficant cost-ef fectiveness for said electrochemical cell ( due to the fact that metallic magnesium is inexpensive ) , high gaseous hydrogen productivity and reduced environmental impact ( since , in particular, there are no greenhouse or harmful gas emissions ) .

[0125] According to a further aspect of the invention, said method comprises a step of electrically connecting said anode 2 and said cathode 3 by means of an electrical circuit 5 and a step of imparting a direct or alternating current to said anode 2 and said cathode 3 , thereby increasing the generation of gaseous hydrogen per unit time .

[0126] In other words , as described above and as illustrated in Figure 2 , said anode 2 and said cathode 3 can be electrically connected by means of an electrical conductor .

[0127] Said electrical conductor may be part of anelectrical circuit 5 configured for said phase to impart a direct or alternating current to said anode 2 and said cathode 3 . This imparted current leads to an increase in the speed of reactions at the anode 2 and cathode 3 , which results in an increase in the generation of gaseous hydrogen per unit time .

[0128] This solution was configured by the Applicant to further increase the productivity of gaseous hydrogen, cost- ef fectively and with reduced environmental impact .

[0129] According to a further aspect of the invention, the step of imparting said direct or alternating current to said anode 2 and said cathode 3 by means of the electrical circuit 5 occurs by means of a voltage preferably comprised in the range 1 V - 10 V .

[0130] This solution was configured by the Applicant to increase the productivity of gaseous hydrogen in an entirely cost-ef fective manner, since for the voltage comprised in this range , the energy cost is entirely negligible compared to the higher productivity o f gaseous hydrogen produced ( i . e . the higher quantity of gaseous hydrogen produced per unit of time has an economic value that is higher than the energy used to obtain it ) . In other words , for voltages above or below the range identi fied by the Applicant , the productivity of gaseous hydrogen does not increase or the productivity / energy cost ratio is lower than that ratio for voltages comprised within that range .

[0131] According to a further aspect of the invention, said method comprises a step of storing electrochemically generated gaseous hydrogen .

[0132] In detail , said storage step comprises a sub-stepof collecting the gaseous hydrogen generated at the electrochemical cell and a sub-step of storing / accumulating the collected gaseous hydrogen . This collection sub-step and this storage / accumulation sub-step are well known from the state of the art for col lecting and storing / accumulating gas in general , but their advantageous application to said generation method by means of said electrochemical cell allows the gaseous hydrogen generated ( i . e . , the product of interest generated by the electrochemical cell ) to be managed appropriately and i f necessary, maximising productivity as inef ficiencies due to gaseous hydrogen leaks are avoided .

[0133] According to a preferred embodiment , said method comprises a sub-step of conveying gaseous hydrogen, said conveying step occurring after said collection sub-step and before said storage / accumulation sub-step .

[0134] This conveying sub-step is well known from the state of the art for the conveyance of gases in general , but its advantageous application to said generation method by means of said electrochemical cell allows the gaseous hydrogen generated ( i . e . , the product of interest generated by the electrochemical cell ) to be conveyed in a suitable manner and i f necessary, maximising productivity as inef ficiencies due to gaseous hydrogen leaks are avoided .

[0135] The apparatus 1 for the electrochemical generation of gaseous hydrogen and the related method as described above enable the above-mentioned aims to be achieved, such as ensuring an important level of cost-ef fectiveness , high productivity and reduced environmental impact .

[0136] Finally, it is clear that modi fications and variations may be made to the apparatus 1 for theelectrochemical generation of gaseous hydrogen and to the related method, described and illustrated herein, without thereby departing from the protective scope of the present invention as defined in the appended claims.PREFERRED CONFIGURATION OF THE INVENTION:

[0137] With reference to Figures 3 to 6, a preferred configuration of the invention is indicated.

[0138] This therefore comprises a container 10 e.g. boxshaped, cubic or of any shape and size.

[0139] It is made of or comprises metallic material in order to function as a cathode.

[0140] Preferably, as described above for other embodiments, this metallic material is selected appropriately on the basis of the electrochemical potential in relation to the electrochemical potential of metallic magnesium, so that the container 10 can act as a cathode and generate a galvanic cell (together with the anode comprising metallic magnesium) .

[0141] It is therefore preferably made of steel, e.g. stainless steel.

[0142] The container 10 can be opened at the top to allow access to its containment volume intended to hold the liquid, i.e. the aqueous solution containing at least one electrolyte, as discussed above.

[0143] As mentioned above, the aqueous solution can preferably be obtained from seawater.

[0144] In all cases, the percentage of sodium chloride is comprised in a preferred range of 20g / l to 40g / l, preferably 25g / l to 40g / l.

[0145] Inside the container 10, the anode is applied tothe wall, which, according to the invention and as described, comprises metallic magnesium.

[0146] Preferably, the anode 20 can be made of at least 90% metallic magnesium and thus could be made entirely of metallic magnesium, on the understanding that, as described above, small percentages of additives (already described and obviously valid for this configuration) may be present.

[0147] For example, AZ91D alloy, which is itself well known and is a magnesium alloy generally used for diecasting, could be used. This high-purity alloy has an excellent combination of mechanical properties and corrosion resistance .

[0148] Alternatively, for example, AZ63HP magnesium alloy could be used.

[0149] Continuing in the structural description of this configuration, the anode 20 may have any conformation.

[0150] However, the Applicant itself has experimentally found that the configuration in which the anode 20 has a parallelepiped plate shape whose thickness is much less than its length is particularly advantageous.

[0151] In particular, an advantageous ratio that has been experimentally proven to provide excellent results in the production of hydrogen is a ratio of 1 / 10, i.e. the thickness is about 1 / 10 of the plate length.

[0152] As shown in Figure 4, the anode is connected to the wall of the container 10 forming the cathode by means of pins 21 (e.g. two pins 21) which are inserted into the wall and which are inserted into the slots 22 formed in the body of the anode, and then the end of these pins is locked into the slot by means of a nut 23 and plate 24.

[0153] Behind the plate 20, an additional plate 25, e.g. made of plastic material, can be attached, whose function is to protect the cathode from direct contact with the anode. In particular, this protective function consists of electrical insulation.

[0154] The two pins 21 serve to close the circuit, thus generating the galvanic cell that produces hydrogen as described above, when the cathode acting as a container is filled with an aqueous solution containing at least one electrolyte .

[0155] According to a further preferred configuration of the invention, it would be possible to connect the anode to a booster 50, which is nothing more than a power supply.

[0156] The power supply can typically be of the AC-DC type, preferably DC, with voltage comprised between 1-10V, e.g. to produce current from 0 to 3A.

[0157] The circuit, via cables 51, then closes on the booster which, by supplying current, is able to accelerate the process and thus, in short, allow a significant increase in hydrogen production.

Claims

CLAIMS1. Apparatus (1) for the electrochemical generation of gaseous hydrogen, starting from an aqueous solution comprising at least one electrolyte, comprising: at least one anode (2) arranged, in use, in said aqueous solution; at least one cathode (3) electrically connected to said anode (2) to form an electrochemical cell, said cathode (3) being arranged, in use, in said aqueous solution, said anode (2) being made of a material comprising at least 90% metallic magnesium;Characterised in that: the cathode is in the form of a container (10) generally box-shaped made of metal forming a containment volume to contain the aqueous solution; said anode (20) is in the form of a plate (20) applied to the wall of the container within its containment volume and wherein behind said plate (20) there is a further insulating plate (25) .

2. Apparatus (1) for the electrochemical generation of gaseous hydrogen, starting from an aqueous solution comprising at least one electrolyte, comprising: at least one anode (2) arranged, in use, in said aqueous solution; at least one cathode (3) electrically connected to said anode (2) to form an electrochemical cell, said cathode (3) being arranged, in use, in said aqueoussolution, said anode (2) is made of a material comprising at least 90% metallic magnesium, Characterised in that said anode material is a metal alloy called AZ63HP, which comprises said magnesium, aluminium and silicon.

3. Apparatus according to claim 1, wherein said anode is a metal alloy comprising said magnesium and at least one further metal selected from the group consisting of: aluminium, silicon, manganese, tin, copper.

4. Apparatus, according to claim 1, wherein said connection of the anode to the container wall is made by means of metal pins (21) which fit into a relative slot (22) formed in the anode and passing through the container wall.

5. Apparatus, according to claim 4, wherein there are two metal pins .

6. Apparatus according to claim 1, wherein said plate (25) is made of plastic material.

7. Apparatus according to claim 1 or one or more of the preceding claims 3 to 6, wherein said anode consists ofa metal alloy called AZ63HP, which comprises magnesium, aluminium and silicon.

8. Apparatus according to one or more of the preceding claims, wherein said anode (2) and said cathode (3) are electrically connected by means of an electrical circuit (50, 51) configured to impart a direct or alternating current to said anode (2) and said cathode (3) increasing the generation of gaseous hydrogen per unit time.

9. Apparatus according to claim 8, wherein said electrical circuit (50, 51) comprises an electrical power supply (50) connected to said anode via a pair of electrical cables (51) and is configured to impart, in use, said direct or alternating current to said anode (2) and said cathode (3) by means of a voltage comprised in the range of 1 V to 10 V.

10. Apparatus according to one or more of the preceding claims, wherein said apparatus comprises a device (6) configured to store electrochemically generated gaseous hydrogen .

11. Apparatus according to one or more of the preceding claims, wherein said aqueous solution comprising atleast one electrolyte consists of an aqueous solution comprising sodium chloride.

12. Apparatus according to claim 11, wherein said aqueous solution comprising sodium chloride has a sodium chloride concentration comprised in the range of 25 g / 1 to 40 g / 1.

13. Apparatus according to one or more of the preceding claims, wherein said anode (2) has a parallelepiped plate conformation in which the thickness is less than the length, preferably according to a thickness ratio of about 1 / 10 of the length.

14. Apparatus according to claim 1, wherein said container is steel, such as stainless steel.

15. Method for the electrochemical generation of gaseous hydrogen starting from an aqueous solution comprising at least one electrolyte, comprising the following steps: immersing at least one anode (2) in said aqueous solution; immersing at least one cathode (3) , electrically connected to said anode (2) to form an electrochemical cell, in said aqueous solution,wherein said anode ( 2 ) is made of a material comprising at least 90% metallic magnesium;And wherein said method is performed with an apparatus in accordance with one or more of the preceding claims 1 to 14 .

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