Method and mechanical device for producing hydrogen

Abstract

A method for producing hydrogen from an aqueous solution containing hydrochloric acid in dissociated form, in which at least one electrode consisting of a metal alloy is present in the aqueous solution, the metal alloy comprising a plurality of metals having different standard reduction potentials, the method comprising the steps of reducing the hydronium ions present in the solution to hydrogen gas as a result of the flow of electrons formed in the electrode from the lower potential metal to the higher potential metal between the metal pairs, and withdrawing the hydrogen gas thus obtained from the aqueous solution.

Description

Technical Field

[0001] This invention relates to a method for producing hydrogen. Background Technology

[0002] Hydrogen is an important raw material used in the chemical and oil refining industries. Due to its low environmental impact and high energy content, there is also growing interest in using hydrogen as a fuel.

[0003] The most common method for large-scale hydrogen production currently involves using hydrocarbons and fossil fuels as starting materials.

[0004] The main hydrocarbon conversion method is steam reforming, which involves the endothermic catalytic conversion of light hydrocarbons (e.g., methane) in the presence of steam.

[0005] Another method is partial oxidation, in which heavy hydrocarbons (e.g., heavy oil residues from the petrochemical industry) are subjected to heat treatment in the presence of oxygen.

[0006] However, hydrocarbon extraction has a very negative impact on the environment because it releases large amounts of carbon dioxide into the atmosphere, leading to an increase in the Earth's thermal balance and the greenhouse effect.

[0007] Currently, various technologies for producing hydrogen under different conditions of obtaining carbon dioxide are being researched.

[0008] One method is water electrolysis. However, this technology has many drawbacks due to the limited amount of hydrogen produced and the high cost of electricity. For these reasons, the amount of hydrogen produced by water electrolysis is currently negligible.

[0009] Hydrogen can also be produced biologically or by thermal decomposition of water. However, these technologies are inefficient for large-scale hydrogen production.

[0010] Therefore, there is an urgent need to develop more energy-efficient, low-cost methods for producing large quantities of hydrogen that can reduce carbon dioxide emissions into the atmosphere. Summary of the Invention

[0011] The present invention aims to provide a method for producing large quantities of hydrogen with reduced energy consumption and low environmental impact.

[0012] According to the method of the present invention, hydrogen gas is produced from an aqueous solution containing hydrochloric acid in its dissociated form, the solution containing hydrated hydrogen ions (H3O). + The aqueous solution contains at least one electrode made of a metal alloy comprising a variety of metals with different standard reduction potentials.

[0013] The method includes the following steps:

[0014] The hydrated hydrogen ions (H3O) present in the solution + The electrons formed in the at least one electrode are reduced to hydrogen (H2) due to the flow of electrons between metal pairs from the lower potential metal to the higher potential metal.

[0015] Take out the hydrogen gas thus obtained from the aqueous solution.

[0016] The aqueous solution is prepared by introducing hydrochloric acid into water, and according to the following formula, it dissociates and releases hydrated hydrogen ions (H3O). + ) and form chloride ions (Cl) - ):

[0017] HCl + H2O → H3O + + Cl - (1)

[0018] Standard reduction potential (E) 0 E is a measure of the tendency of a chemical substance to gain electrons (i.e., be reduced). 0 The higher the value, the greater the electron affinity of the substance, and therefore the greater its tendency to be reduced. Standard reduction potential (E0) 0 () is relative to the potential E 0 It is defined by a standard hydrogen electrode of 0.00 V and is measured under standard conditions, namely at a temperature of 298 K (25 °C) and a pressure of 100 kPa (1 bar).

[0019] The potential difference between each metal pair must be large enough to ensure that the electron flow migrates from the metal with the lower potential to the metal with the higher potential. Preferably, the potential difference is equal to at least 0.20 volts, more preferably at least 0.50 volts.

[0020] In each metal pair that generates the electron flow therein, the metal that releases electrons acts as the anode and is oxidized according to the following half-reaction, acting as a reducing agent:

[0021] M → M n+ + ne - (2)

[0022] “ n " is an integer, preferably 2 or 3.

[0023] The metal that accepts electrons acts as an inert cathode, where H3O present in the solution is present. + The ion acts as an oxidizing agent and gains electrons according to the following half-reaction:

[0024] 2H + + 2e - → H2 (3)

[0025] Specifically, the following redox reaction occurs on at least one of the electrodes:

[0026] H2O (l) → O2 (g) + 2H2 (g) (4)

[0027] This results in the formation of hydrogen and oxygen.

[0028] The metal alloy forming the at least one electrode preferably comprises magnesium and at least one of the following metals: beryllium (Be), aluminum (Al), manganese (Mn), zinc (Zn), iron (Fe), copper (Cu), silicon (Si), and nickel (Ni).

[0029] In a preferred embodiment, the metal alloy primarily comprises magnesium. In a particularly preferred embodiment, the metal alloy contains 85% to 95% magnesium by weight, preferably 90% to 91%.

[0030] Magnesium has the lowest standard reduction potential among the various metals, and therefore has the greatest tendency to transfer electrons. Thus, when the metal alloy comes into contact with an aqueous solution, electron migration occurs from magnesium to each of the various metals. Therefore, magnesium always acts as the anode, oxidized according to half-reaction (2), where the value of n is 2.

[0031] Silicon is the metal with the highest standard reduction potential in the group of metals, so silicon always acts as an inert cathode, in which, according to half reaction (3), hydrated hydrogen ions present in the solution gain electrons to form hydrogen gas.

[0032] Each metal, possessing an intermediate standard reduction potential between that of Mg and Si, serves as either an inert cathode or an anode for oxidation according to half-reaction (2), depending on the metal with which it exchanges electrons. When half-reaction (2) involves metals such as Be, Mn, Zn, Fe, Cu, and Ni, n The value is assumed to be 2; conversely, when it involves metals such as Al, n The value is assumed to be 3.

[0033] In a preferred embodiment of the invention, the metal alloy has the following percentage (%) composition by weight: 90.81% Mg, 5.83% Al, 2.85% Zn, 0.45% Mn, 0.046% Si, 0.0036% Cu, 0.0012% Be, 0.0010% Fe, and 0.00050% Ni.

[0034] According to another embodiment of the invention, the metal alloy has the following percentage (%) composition by weight: 90.65% Mg, 5.92% Al, 2.92% Zn, 0.46% Mn, 0.043% Si, 0.0036% Cu, 0.0012% Be, 0.0010% Fe, and 0.00050% Ni.

[0035] According to a particularly advantageous embodiment of the invention, the outer surface of the at least one electrode is coated with a coating comprising at least one metal fluoride, particularly magnesium fluoride, aluminum fluoride and / or zinc fluoride.

[0036] Preferably, the at least one electrode is coated with a coating comprising one or more of the aforementioned metal fluorides mixed with a methacrylic resin. Even more preferably, the methacrylic resin comprises 50% to 70% (by weight) PFTE, 15% to 25% (by weight) 1,2-propanediol monomethyl methacrylate (CAS. 27813-02-1), and 15% to 25% (by weight) hydroxyethyl methacrylate (CAS 868-77-9).

[0037] According to a preferred embodiment of the present invention, the methacrylate resin comprises 60% (by weight) PFTE, 20% (by weight) 1,2-propanediol monomethyl methacrylate (CAS.27813-02-1) and 20% (by weight) hydroxyethyl methacrylate (CAS 868-77-9).

[0038] Preferably, the coating of the at least one electrode has a thickness of 0.5 mm to 3.0 mm, more preferably, a thickness of 1.0 mm to 2.0 mm.

[0039] According to a more preferred embodiment of the invention, the at least one electrode has a graphite element at one end, which is not covered by the aforementioned coating on the outer surface of the electrode.

[0040] Advantageously, a metal element, such as an iron or carbon steel rod, is also provided inside the at least one electrode, which contacts the graphite element of the electrode.

[0041] According to another embodiment of the invention, the outer coating of the at least one electrode is covered with a perforated tape or PTFE mesh. Preferably, the perforated tape or PTFE mesh applied to the coating has a thickness of several micrometers, for example, 1 µm to 3 µm.

[0042] According to another embodiment of the invention, the outer coating of the at least one electrode is covered with a semi-permeable fabric tape, which is permeable to an aqueous solution flowing toward the electrode but impermeable to an aqueous solution flowing in the opposite direction. The fabric is also permeable to hydrogen gas.

[0043] The aforementioned aqueous solution is prepared by introducing hydrochloric acid into water to form a mixture. Preferably, the mixture contains 5% to 10%, more preferably 6% to 7% hydrochloric acid. These percentages are by volume.

[0044] The percentage of hydrochloric acid in the aqueous solution causes the method of the present invention to be carried out in an acidic environment. The pH at which the method occurs is preferably in the range of 2 to 4, more preferably in the range of 2 to 3.4.

[0045] Preferably, the method is carried out at a temperature in the range of 20°C to 70°C, more preferably in the range of 55°C to 60°C.

[0046] Preferably, the method is carried out at a pressure below atmospheric pressure, for example, an absolute pressure of 0.3 bar to 0.5 bar.

[0047] Due to the low molecular weight of hydrogen, the hydrogen thus obtained is released spontaneously from the solution.

[0048] Given the high molecular weight of oxygen, the oxygen produced during the method will instead remain in the aqueous solution and will tend to combine with chlorine, which is also present in the aqueous solution, to form hypochlorous acid (HClO).

[0049] According to a preferred embodiment of the invention, to avoid the accumulation of hypochlorous acid in the aqueous solution, the aqueous solution is advantageously regenerated by a recycling step and a degassing step, which are adapted to remove the generated oxygen and the hydrogen produced during the reduction step described above with reference to half-reaction (3). The degassing step includes a filtration step in which oxygen is removed.

[0050] Specifically, a porous baffle membrane filter filled with MnO2 is preferably used to perform the filtration step, during which oxygen (O2) and chlorine (Cl2) are released separately. The chlorine is then recovered by reintroducing it into the aqueous solution (preferably by bubbling).

[0051] Preferably, the degassing step is performed under vacuum.

[0052] Since the reaction that forms the basis of the method according to the invention is exothermic, the recycling step also preferably includes a step of cooling an aqueous solution suitable for maintaining the reaction temperature within the aforementioned range.

[0053] Another aspect of the present invention relates to mechanical equipment for producing hydrogen according to the aforementioned method. This mechanical equipment includes:

[0054] At least one buffer tank for storing an aqueous solution containing hydrochloric acid in its dissociated form;

[0055] At least one reactor for producing hydrogen, wherein at least one electrode made of a metal alloy comprising a variety of metals having different standard reduction potentials is placed in the at least one reactor.

[0056] At least one feed line for supplying the aqueous solution from the at least one buffer tank to the at least one reactor;

[0057] At least one recirculation line for recirculating the aqueous solution from the at least one reactor to the at least one buffer tank;

[0058] At least one device for regenerating the aqueous solution, the device being arranged along the at least one recirculation line, and

[0059] A component for removing hydrogen from the at least one reactor.

[0060] Preferably, the regeneration device includes a filtration device comprising, for example, at least one porous baffle membrane filter, preferably a porous baffle membrane filter filled with MnO2, the filter being suitable for separating oxygen (O2) (degassing) formed during hydrogen production in the at least one reactor. Preferably, the filtration device operates under vacuum.

[0061] Preferably, the mechanical device according to the invention also includes at least one cooling device along the recirculation pipeline, the cooling device including at least one heat exchanger adapted to cool the aqueous solution effluent from the at least one reactor and maintain the reaction temperature in the range of 20°C to 70°C.

[0062] According to a particularly advantageous embodiment, the cooling device is located upstream of the regeneration device.

[0063] In some embodiments, the mechanical device includes two parallel reactors, each reactor having its own feed line and recirculation line for the aqueous solution, its own means for regenerating the aqueous solution circulating in the recirculation line, and its own hydrogen extraction component.

[0064] Another object of the present invention relates to an electrode made of a metal alloy for use in the aforementioned hydrogen production method. For details regarding the composition of the metal alloy used to prepare the electrode, the actual structure of the electrode, and its coating, please refer to the method-related description provided.

[0065] The purpose of this invention is also to provide an aqueous solution for use in the aforementioned hydrogen production method, containing hydrated hydrogen ions (H3O). + ) and chloride ions (Cl - ).

[0066] Another object of the present invention is a method for coating the outer surface of the at least one electrode.

[0067] The method includes:

[0068] - Involves the step of immersing the at least one electrode in a hydrofluoric acid and water bath, wherein the metal constituting the outer surface of the electrode reacts with the hydrofluoric acid to form a fluorinated patina of a metal fluoride salt.

[0069] - The first step of drying the fluorinated thin layer of the metal fluoride salt;

[0070] - The step of applying methacrylic resin gel onto the fluorinated thin layer, wherein the methacrylic resin is of the type described in relation to the method;

[0071] A second step, drying the mixture thus obtained, comprising metal fluoride and methacrylic resin, yields an outer coating for the electrode.

[0072] Preferably, the second drying step has a duration of 10 to 16 hours, more preferably 12 hours.

[0073] According to a preferred embodiment of the invention, the method of coating the electrode further involves wrapping the electrode with a perforated tape or PTFE mesh at the end of the second drying step. Preferably, the perforated tape or PTFE mesh has a thickness of several micrometers, for example, 1 µm to 3 µm.

[0074] According to another embodiment of the invention, the step of coating the electrode is performed using a semi-permeable fabric strip, which is permeable to an aqueous solution flowing toward the electrode but impermeable to an aqueous solution flowing in the opposite direction. The fabric is also permeable to hydrogen gas.

[0075] The advantages of this invention are that it provides a method for producing large quantities of hydrogen with low energy consumption, since hydrogen can be obtained with virtually no external input of heat and electricity; it has low environmental impact, since the method does not release CO2 into the atmosphere; and it is low in cost, since hydrochloric acid is a commercially available substance.

[0076] The advantages of the present invention will be made clearer by the following detailed description, which relates to preferred embodiments provided in a non-limiting manner. Attached Figure Description

[0077] Figure 1 A diagram showing a mechanical apparatus for producing hydrogen according to a preferred embodiment of the method of the present invention.

[0078] Figure 2 Detailed display based on Figure 1 Electrodes in a diagram of mechanical equipment. Detailed Implementation

[0079] Figure 1 This diagram shows a mechanical apparatus 100 for the continuous production of hydrogen. The mechanical apparatus 100 mainly includes: a buffer tank 1 for storing an aqueous solution 20; two reactors 2 and 3 for producing hydrogen, the two reactors 2 and 3 being identical and arranged in parallel; respective pipelines 21, 22 and 21, 23 for supplying the aqueous solution from the buffer tank 1 to the reactors 2 and 3; and components 4 and 5, such as conventional discharge pipes, for removing the hydrogen produced in the aforementioned reactors 2 and 3.

[0080] Each reactor 2 and 3 includes a cartridge, designated by reference numerals 6 and 7, respectively, containing multiple electrodes made of a metal alloy composed of metals with different standard reduction potentials.

[0081] The metal alloy comprises magnesium and at least one of the following metals: beryllium (Be), aluminum (Al), manganese (Mn), zinc (Zn), iron (Fe), copper (Cu), silicon (Si), and nickel (Ni). Preferably, the magnesium content is 85% to 95% by weight, more preferably 90% to 91%.

[0082] The electrode is obtained from the aforementioned metal in granular form according to the following method, wherein the metal is mixed and heated until it is completely melted, and wherein the resulting melt is cast into a specific mold, which cools and solidifies inside the mold. Finally, the electrode according to the invention is removed from the mold.

[0083] According to a preferred embodiment of the invention, a metal element, such as an iron or carbon steel rod, is placed inside the mold before the molten metal is cast. Preferably, the metal element is placed inside the mold such that its end does not contact the molten metal. Once the molten metal has cooled and the electrode has been removed from the mold, the aforementioned end of the metal element will be located outside the electrode and protrude from it.

[0084] A preferred embodiment of the electrode according to the invention is shown in Figure 2 .

[0085] The Figure 2 The electrode 200 is schematically shown, comprising a generally cylindrical body 201 composed of the aforementioned metal alloy and having a metal rod 202 disposed therein. The rod 202 protrudes from the cylindrical body 201 at its end 203. The end 203 has a graphite element 204 fixed to it. Preferably, the graphite element is screwed onto the end of the rod 202 and a plastic washer 205 is placed between the graphite element 204 and the cylindrical body 201. This creates contact between the graphite element 203 and the rod 202.

[0086] The cylindrical body 201 also has an outer coating, usually designated 206, and includes a layer 207 of at least one metal fluoride mixed with methacrylate resin 208, particularly magnesium fluoride, aluminum fluoride and / or zinc fluoride. The methacrylate resin 208 is preferably 60% (by weight) PFTE, 20% (by weight) 1,2-propanediol monomethyl methacrylate (CAS.27813-02-1) and 20% (by weight) hydroxyethyl methacrylate (CAS 868-77-9).

[0087] Advantageously, the outer coating 206, comprising at least one metal fluoride and methacrylic resin, is covered by a perforated tape or PTFE mesh 209 having a thickness of several micrometers, for example, 1 µm to 3 µm.

[0088] exist Figure 1 In one embodiment, the electrodes and cartridges 6 and 7 are respectively positioned inside reactors 2 and 3 at elevated positions relative to the bottom.

[0089] Each reactor 2 and 3 is in fluid communication with buffer tank 1 via respective lines 26, 28 and 27, 28 for recirculating an aqueous solution, which is then processed by a series of devices. Specifically, each reactor 2 and 3 is in fluid communication with cooling devices 9 and 8 via the aforementioned recirculation lines, which consist of at least one heat exchanger (not shown). The aqueous solution from cooling devices 8 and 9 flows to a filtration device 10, which includes a porous baffled membrane filter, preferably a porous baffled membrane filter (not shown) filled with MnO2, capable of separating oxygen (O2) formed during hydrogen production in reactors 2 and 3 (degassing).

[0090] Each recirculation line 26, 28, 27, 28 is connected to the interior of reactors 2 and 3 via specific extraction pipes 12 and 13, which extend substantially to the bottom of the reactors. Specifically, the openings of the extraction pipes 12 and 13 are located between the bottom of reactors 2 and 3 below cartridges 6 and 7 and the base of the cartridges themselves.

[0091] The mechanical equipment also includes one or more pipelines for internal recirculation of the aqueous solution present in buffer tank 1. These pipelines can be connected, via their respective connecting pipes, to pipelines supplying the aqueous solution to the reactor, as needed. Figure 1 In the illustrated embodiment, there are two internal recirculation lines 24 and 25, which are connected to supply lines 22 and 23 via their respective connecting pipes 24b and 25b.

[0092] The mechanical equipment also includes a section 14 located upstream of the buffer tank 1, in which an aqueous solution 20 is prepared by mixing an acid solution 40 of hydrochloric acid and tap water 41. The section 14 mainly includes a tank 15 for storing the acid solution 40, a device 16 for filtering tap water, and a pipeline 42 for supplying the filtered water.

[0093] The flow of tap water 41 is controlled by valve V1 located upstream of filter device 16 and check valve V2 located downstream of filter device 16. Solution 40 is pumped by pneumatic pump P1 connected to tank 15. When buffer tank 1 is filled, pneumatic pump P1 is started and pneumatic valve V3 is opened. Then, solution 40 passes through check valve V4 and mixes with filtered tap water 42 to form the aforementioned aqueous solution 20.

[0094] The aqueous solution 20 preferably contains 3% to 20% by volume, 5% to 10% by volume, and more preferably 6% to 7% by volume of hydrochloric acid.

[0095] During use, operate the mechanical equipment 100 in the following manner:

[0096] Buffer tank 1 is filled with aqueous solution 20. The aqueous solution is then supplied to reactors 2 and 3 until their respective liquid levels L1 and L2 are reached.

[0097] For more details and reference Figure 1 In the embodiment shown, the aqueous solution leaving the buffer tank 1 via pipeline 21 is pumped by pump P2, delivered by flow meter 17 controlling the filling of reactors 2 and 3, and then divided into two parts, which are supplied to reactors 2 and 3 via pipelines 22 and 23 through their respective pneumatic valves V8 and V9.

[0098] Once the reactor is filled, the aqueous solution remains inside the reactor for a predetermined time, preferably several minutes, and reacts in the presence of electrodes according to reaction (4): H2O(l) → O2(g) + 2H2(g) to produce hydrogen and oxygen. The reaction temperature is preferably 55°C to 60°C and the pressure is 2.5 bar to 3 bar.

[0099] Due to the low molecular weight of hydrogen, the hydrogen thus obtained is released from the solution and accumulates in collection chambers inside reactors 2 and 3, which are located between liquid levels L1 and L2 and the respective reactor lids. The hydrogen accumulated in the chambers is removed from reactors 2 and 3 through respective discharge pipes 4 and 5 and stored in suitable tanks (not shown).

[0100] The aqueous solution is extracted through its respective extraction pipes 12 and 13 and recirculated in the recirculation lines 26 and 27. The extraction of the aqueous solution is controlled by pneumatic valves V5 and V6, and the opening of pneumatic valves V5 and V6 is controlled by the liquid levels L1 and L2 in reactors 2 and 3.

[0101] The openings of extraction tubes 12 and 13 are positioned lower than those of cartridges 6 and 7, ensuring that hydrogen gas generated at the electrodes is not drawn into the recirculation lines 26 and 27 along with the aqueous solution.

[0102] The aqueous solution taken from the reactor via recirculation lines 26 and 27 first undergoes a cooling step in the heat exchangers of cooling devices 8 and 9, which is carried out through indirect heat exchange with cooling water flow (not shown). Cooling the aqueous solution circulating in recirculation lines 26 and 27 maintains a constant temperature inside reactors 2 and 3, preferably a constant temperature of 55°C to 60°C.

[0103] The cooled aqueous solution then undergoes a degassing step to remove oxygen from the aqueous solution. This degassing step includes a filtration step, which is preferably performed under vacuum inside the filtration device 10. Thereby, oxygen is separated from the aqueous solution and removed via a specific discharge pipe 32. The term "under vacuum" refers to a pressure slightly less than 1 bar, for example, 0.5 to 0.8 bar.

[0104] During the filtration process performed inside apparatus 10 using a porous baffled membrane filter (preferably filled with MnO2) (not shown), chlorine gas (Cl2) is released in addition to oxygen. The chlorine gas is then recovered by reintroducing it into the aqueous solution (preferably by bubbling).

[0105] The aqueous solution, which is essentially free of oxygen, is then recirculated to the buffer tank 1 via recirculation line 28.

[0106] Aqueous solution 20 is continuously reintroduced from buffer tank 1 into reactors 2 and 3 via supply lines 21, 22 and 21, 23 to maintain constant liquid levels L1 and L2. The aqueous solution 20 is kept in constant flow by recirculating it through internal recirculation lines 24 and 25. To allow recirculation, the aqueous solution is pumped via respective pumps P3 and P4.

[0107] During operations involving inspection or maintenance of reactors 2 and 3, reactors 2 and 3 are emptied via their respective channels 29 and 30, and the aqueous solution is fed in a stream 31 to a waste collection tank (not shown). During these operations, electrode regeneration can be performed if necessary. Specifically, the outer coating 206 of the electrodes can be restored by immersing them in an aqueous solution containing hydrofluoric acid for an appropriate period of time (e.g., 10 to 20 minutes, preferably 15 minutes).

[0108] If necessary, during operation of the mechanical equipment, a portion of the aqueous solution circulating in the internal recirculation lines 24 and 25 can be supplied to reactors 2 and 3 via their respective pipes 24b and 25b, which connect the internal recirculation lines 24 and 25 to their respective supply lines 22 and 23.

[0109] The device used in the mechanical equipment is advantageously implemented in a sealed manner, preferably made of steel, and the buffer tank 1, in addition to the filter device 10, also operates under vacuum. In this case, the pressure inside the buffer tank 1 is 0.03 bar to 0.08 bar. This prevents oxygen present in the aqueous solution from coming into contact with the outside air.

[0110] The following describes an embodiment of the method according to the present invention.

[0111] Example

[0112] Two identical cylindrical reactors, each 120 cm high and 30 cm in diameter, were used.

[0113] In each reactor, a cartridge containing 32 electrodes is introduced. These electrodes are also cylindrical, 40 cm high and 4 cm in diameter, and are made of a metal alloy composed of the following: 90.81% Mg, 5.83% Al, 2.85% Zn, 0.45% Mn, 0.046% Si, 0.0036% Cu, 0.0012% Be, 0.0010% Fe, and 0.00050% Ni.

[0114] The cartridge is positioned at a height of approximately 20 cm from the bottom of the reactor.

[0115] Next, each reactor was filled with a solution containing water and hydrochloric acid, with a total volume of 25 liters.

[0116] The aforementioned solution was prepared by introducing 2.36 liters of 38% hydrochloric acid solution into a certain amount of tap water to fill the aforementioned 25-liter volume.

[0117] Therefore, the composition of the solution in the reactor is as follows: 26.464 liters of water and 0.896 liters of hydrochloric acid.

[0118] In other words, the mixture contains 96.72% by volume tap water and 3.28% hydrochloric acid.

[0119] The solution has a residence time of approximately 15 minutes and can be applied at a concentration of 22 Nm. 3 Hydrogen is produced at a rate of / h. This hydrogen production method advantageously achieves an energy consumption of less than 1.5 kWh.

[0120] According to a further embodiment, the method of the present invention also includes providing hydrofluoric acid (HF) to an aqueous solution (20) containing hydrochloric acid in its dissociated form. Preferably, 50 ml to 70 ml, most preferably 60 ml, of this hydrofluoric acid (HF) is added to every 10,000 ml of the aqueous solution.

[0121] In this regard, besides hydrated hydrogen ions (H3O) + ) and chloride ions (Cl - In addition, the aqueous solution used in the method of the present invention also contains the amount of hydrofluoric acid (HF) as described above. In this aqueous solution, the hydrofluoric acid undergoes ion dissociation.

[0122] By irradiating the electrodes with visible coherent light (especially LED light), particularly satisfactory hydrogen (H2) production results can be obtained, with a yield increase of up to 20%.

Claims

1. A method for producing hydrogen from a solution (20) composed of aqueous hydrochloric acid in its dissociated form, said solution containing hydrated hydrogen ions (H3O4). + The solution contains at least one electrode made of a metal alloy, the metal alloy comprising a variety of metals with different standard reduction potentials, wherein the metal alloy comprises magnesium and at least one of the following metals: beryllium (Be), aluminum (Al), manganese (Mn), zinc (Zn), iron (Fe), copper (Cu), silicon (Si), and nickel (Ni). The method includes the following steps: The hydrated hydrogen ions (H3O) present in the solution + The reduction to hydrogen (H2) is due to the flow of electrons formed in the at least one electrode made of a metal alloy from the metal with the lower potential to the metal with the higher potential between metal pairs, and Remove the hydrogen gas thus obtained from the solution.

2. The method according to claim 1, wherein the metal alloy mainly comprises magnesium.

3. The method of claim 2, wherein the metal alloy comprises a magnesium content ranging from 85% to 95% by weight.

4. The method of claim 3, wherein the magnesium content ranges from 90% to 91% by weight.

5. The method according to any one of claims 1-4, wherein the metal alloy of the at least one electrode made of a metal alloy comprises the following components: A) By weight, 90.81% Mg, 5.83% Al, 2.85% Zn, 0.45% Mn, 0.046% Si, 0.0036% Cu, 0.0012% Be, 0.0010% Fe, 0.00050% Ni; or B) By weight, 90.65% Mg, 5.92% Al, 2.92% Zn, 0.46% Mn, 0.043% Si, 0.0036% Cu, 0.0012% Be, 0.0010% Fe, 0.00050% Ni.

6. The method of claim 1, wherein the outer surface of the at least one electrode made of a metal alloy is coated with a coating comprising at least one metal fluoride.

7. The method according to claim 6, wherein the at least one metal fluoride is selected from magnesium fluoride, aluminum fluoride and / or zinc fluoride.

8. The method of claim 6, wherein the coating comprises the at least one metal fluoride mixed with methacrylic resin.

9. The method of claim 8, wherein the methacrylate resin comprises 50% to 70% by weight of PFTE, 15% to 25% by weight of 1,2-propanediol monomethyl methacrylate CAS.27813-02-1 and 15% to 25% by weight of hydroxyethyl methacrylate CAS 868-77-9.

10. The method of claim 9, wherein the methacrylic resin comprises 60% by weight of PFTE, 20% by weight of 1,2-propanediol monomethyl methacrylate (CAS.27813-02-1), and 20% by weight of hydroxyethyl methacrylate (CAS.868-77-9).

11. The method according to any one of claims 6-10, wherein the coating of the at least one electrode made of a metal alloy has a thickness of 0.5 mm to 3.0 mm.

12. The method of claim 11, wherein the thickness is 1.0 mm to 2.0 mm.

13. The method of claim 6, wherein the at least one electrode made of a metal alloy has a graphite element at one end, and wherein the coating on the outer surface of the at least one electrode made of a metal alloy does not cover the graphite element.

14. The method of claim 13, wherein a metal element is provided inside the at least one electrode made of a metal alloy, the metal element being in contact with the graphite element.

15. The method according to claim 14, wherein the metal element is an iron or carbon steel rod.

16. The method according to any one of claims 6-10 or 13-15, wherein the coating is covered with a perforated tape or PTFE mesh or a semi-permeable fabric tape, which is permeable to the solution passing toward the electrode but impermeable to the solution in the opposite direction.

17. The method according to any one of claims 1-4, 6-10 or 13-15, wherein the solution contains hydrochloric acid at a concentration of 5% to 10%.

18. The method according to any one of claims 1-4, 6-10 or 13-15, wherein the pH of the solution is in the range of 2 to 4.

19. The method according to any one of claims 1-4, 6-10 or 13-15, wherein the reaction of reducing hydrated hydrogen ions to hydrogen gas occurs at a temperature of 20°C to 70°C.

20. The method according to claim 19, wherein, The temperature is between 55°C and 60°C.

21. The method according to any one of claims 1-4, 6-10 or 13-15, wherein the reaction of reducing hydrated hydrogen ions to hydrogen gas occurs at a pressure below atmospheric pressure.

22. The method of claim 1, wherein the solution is regenerated by a solution recirculation step and a degassing step, and the degassing step includes a filtration step in which oxygen is removed from the solution.

23. The method of claim 22, wherein the filtration step is performed using a porous baffled membrane filter, wherein both oxygen (O2) and chlorine (Cl2) are released.

24. The method of claim 23, wherein the chlorine gas thus released is recovered and reintroduced into the solution.

25. The method of claim 24, wherein the chlorine gas thus released is recovered and reintroduced into the solution by bubbling.

26. The method according to any one of claims 22-25, wherein the recycling step includes a step of cooling the solution to keep the reaction temperature substantially constant.

27. The method of claim 1, wherein the method comprises irradiating one or more of the electrodes with visible coherent light.

28. The method of claim 27, wherein the method comprises irradiating one or more of the electrodes with LED light.

29. A mechanical apparatus for producing hydrogen according to any one of claims 1-28, the mechanical apparatus comprising: At least one buffer tank (1) for storing a solution (20) consisting of aqueous hydrochloric acid in its dissociated form. At least one reactor (2, 3) for producing hydrogen, wherein at least one electrode made of a metal alloy as defined in claim 1 is placed inside the at least one reactor (2, 3); the metal alloy comprises a variety of metals having different standard reduction potentials. At least one feed line (22, 23) is provided for feeding the solution from the at least one buffer tank (1) to the at least one reactor (2, 3). At least one recirculation line (26, 28); 27, 28), used to recycle the solution from the at least one reactor (2, 3) to the at least one buffer tank (1); At least one device (10) for regenerating the solution, the device being along the at least one recirculation line (26, 28); Settings for 27 and 28, and Components (4, 5) are used to extract hydrogen from the at least one reactor.

30. The mechanical device according to claim 29, wherein the at least one device (10) for regeneration includes a filtration device comprising at least one porous baffle membrane filter capable of separating oxygen (O2) from the solution.

31. The mechanical device according to claim 30, wherein the filtration device operates under vacuum.

32. The mechanical equipment according to any one of claims 29-31, comprising at least one cooling device (8, 9) along the at least one recirculation line (26, 28; 27, 28).

33. An electrode for a method of producing hydrogen according to any one of claims 1-28, said electrode being made of a metal alloy, wherein said metal alloy is composed of the following components: A) By weight, 90.81% Mg, 5.83% Al, 2.85% Zn, 0.45% Mn, 0.046% Si, 0.0036% Cu, 0.0012% Be, 0.0010% Fe, 0.00050% Ni; or B) By weight, 90.65% Mg, 5.92% Al, 2.92% Zn, 0.46% Mn, 0.043% Si, 0.0036% Cu, 0.0012% Be, 0.0010% Fe, 0.00050% Ni.

34. The electrode of claim 33, wherein the outer surface of the electrode is coated with a coating comprising at least one metal fluoride.

35. The electrode according to claim 34, wherein the at least one metal fluoride is magnesium fluoride, aluminum fluoride and / or zinc fluoride.

36. The electrode of claim 34, wherein the coating comprises the at least one metal fluoride mixed with methacrylic resin.

37. The electrode of claim 36, wherein the methacrylate resin comprises 50% to 70% by weight of PFTE, 15% to 25% by weight of 1,2-propanediol monomethyl methacrylate CAS.27813-02-1 and 15% to 25% by weight of hydroxyethyl methacrylate CAS 868-77-9.

38. The electrode of claim 37, wherein the methacrylate resin comprises 60% by weight PFTE, 20% by weight 1,2-propanediol monomethyl methacrylate CAS.27813-02-1 and 20% by weight hydroxyethyl methacrylate CAS 868-77-9.

39. The electrode according to any one of claims 34-38, wherein the coating of the electrode has a thickness of 0.5 mm to 3.0 mm.

40. The electrode of claim 39, wherein the thickness is 1.0 mm to 2.0 mm.

41. The electrode according to any one of claims 34-38, wherein the electrode has a graphite element at one end, and wherein the coating on the outer surface of the electrode does not cover the graphite element.

42. The electrode of claim 41, wherein a metal element is provided inside the electrode, the metal element being in contact with the graphite element.

43. The electrode according to claim 42, wherein the metal element is an iron or carbon steel rod.

44. The electrode according to any one of claims 34-38, wherein the coating is covered with a perforated tape or a PTFE mesh or a semi-permeable fabric tape, which is permeable to the solution according to claim 1 passing toward the electrode, but impermeable to the solution in the opposite direction.

45. A method for coating an electrode made of a metal alloy, said metal alloy comprising a plurality of metals having different standard reduction potentials, said electrode made of the metal alloy as described in any one of claims 1-28, the coating method comprising: - The step of immersing the electrode in a hydrofluoric acid and water bath, wherein the metal constituting the outer surface of the electrode reacts with the hydrofluoric acid to form a fluorinated thin layer of metal fluoride salt; - The first step of drying the fluorinated thin layer of the metal fluoride salt; - The step of applying methacrylic resin gel onto the fluorinated thin layer; - The second step is to dry the mixture thus obtained, which contains metal fluoride and methacrylic resin.

46. ​​The method of claim 45, wherein the methacrylate resin comprises 50% to 70% by weight of PFTE, 15% to 25% by weight of 1,2-propanediol monomethyl methacrylate CAS.27813-02-1 and 15% to 25% by weight of hydroxyethyl methacrylate CAS 868-77-9.

47. The method according to claim 45 or 46, wherein at the end of the second step, the electrode is covered with a perforated tape or PTFE mesh or a semi-permeable fabric tape, which is permeable to the solution according to claim 1 passing toward the electrode, but impermeable to the solution in the opposite direction.

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