EP2925908A1

EP2925908A1 - Apparatus and method for generating hydrogen and oxygen

Info

Publication number: EP2925908A1
Application number: EP12812389.0A
Authority: EP
Inventors: Dino GHINI
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-11-28
Filing date: 2012-11-28
Publication date: 2015-10-07
Also published as: WO2014083385A1

Abstract

An apparatus for generating hydrogen and oxygen comprises; - a container (2) made of electrically insulating material and defining an internal volume (20), - a casing (3) made of electrically conductive metal material, inserted into said internal volume (20), - side plate means (4, 5) made of zinc and/or cadmium metal alloy and fixed in contact with opposite sides (16, 17) of central plate means (6) made of metal alloy containing one or more transition metals, in particular iron and/or nickel, said side plate means (4, 5) and said central plate means (6) being housed inside said casing (3), said side plate means (4, 5) being in electrical connection with the latter; - a reaction solution (S) arranged for filling said internal volume (20) until it covers completely said casing (3) and arranged for interacting with said side plate means (4, 5) and said central plate means (6) to generate hydrogen and oxygen in gaseous form, said reaction solution comprising water, a non ionic surfactant containing hydrochloric acid (HCl), titanium dioxide (TiO2) in powder form, a phosphoric acid solution (H3PO4) and an acid solution containing sulphuric acid (H2SO4).

Description

Apparatus and method for generating hydrogen and oxygen

The invention relates to apparatuses and methods for generating hydrogen, and in particular it refers to an apparatus and a method for generating hydrogen and oxygen in gaseous form from an acid water solution.

Processes and methods are known for generating hydrogen by extraction from hydrocarbons and/or fossil fuels or by extraction from water.

The methods of extraction of hydrogen from hydrocarbons (for example natural gas, methane) and from fossil fuels (for example coal) are numerous and relatively effective. Such processes are nevertheless polluting and harmful for the environment as the cause the formation of more or less toxic and harmful by-products and anyway the production of large quantities of carbon oxides (CO, C02) that are released into the atmosphere.

Hydrogen can be extracted directly from the water by chemical processes that require the use of external electric and/or thermal energy.

In electrolysis processes an electric current is used that traverses the water to generate hydrogen and oxygen in gaseous form.

In thermolysis processes thermal energy is used to activate and maintain active the thermochemical reactions that enable the hydrogen to be extracted.

Hybrid or mixed extraction processes are also known that comprise combined thermochemical and electrochemical cycles.

A drawback of these known methods of extracting hydrogen from water consists of the fact that they are not economically favourable for large scale production because they require the supply of energy from the exterior that is not always available and is anyway expensive to produce. Further, these processes require complex, costly and bulky equipments and plants.

An object of the present invention is to improve known apparatuses and methods for generating hydrogen in gaseous form.

Another object is to make an apparatus and a method that enable large quantities of hydrogen and oxygen in gaseous form to be generated from an inexpensive acid water solution, without the need to supply external electric and/or thermal energy.

A further object is to obtain an apparatus and a method that enables hydrogen and oxygen to be generated by exothermic electrochemical reactions that develop little heat.

Still another object is to devise an apparatus for generating hydrogen and oxygen that is very compact, can be dimensioned according to the required production and is easily transported and installed at the end users.

In a first aspect of the invention an apparatus is provided for generating hydrogen and oxygen according to claim 1. In a second aspect of the invention a method is provided for generating hydrogen and oxygen according to claim 19.

The invention can be better understood and implemented with reference to the attached drawings that illustrate some embodiments thereof by way of non limiting example, in which:

figure 1 is a partially sectioned schematic frontal view of the apparatus for generating hydrogen and oxygen according to the invention;

figure 2 is an enlarged cross section according to line II-II of figure 1 , in which some parts have been removed;

figure 3 is an enlarged and partially sectioned perspective view of a casing and of plate means of the apparatus in figure 1.

With reference to figures 1 to 3, an apparatus is illustrated for generating hydrogen and oxygen in gaseous form comprising a container 2 in electrically insulating material, in particular plastics, which defines an internal volume 20 that is suitable for housing a casing 3 made of electrically conductive metal material, in particular stainless steel, for example AISI 316A steel. The container 2, has, for example, a cylindrical shape and is closed at opposite ends by covers 24 fixed reversibly by, for example, bolts, to fixing flanges of said opposite ends. The material of the container 2 is moreover acid-proof.

Inside the casing 3 there is provided side plate means 4, 5 made of zinc and/or cadmium metal alloy and central plate means 6 made of a metal alloy containing one or more transition metals, i.e. elements of the "d" sector of the periodic table of the elements, in particular iron and/or nickel. The side plate means 4, 5 is fixed and in contact on opposite sides 16, 17 of the central plate means 6 in such a manner as to permit the passage of electric current. The side plate means 4, 5 and the central plate means 6 constitute a sort of galvanic cell and act as electrodes in the process of hydrogen generation explained in detail further on in the description.

The side plate means 4, 5 is in electrical connection with the casing 3. For this purpose, a joint element 11 is provided that is made of zinc and placed in contact with the side plate means 4, 5 and interposed between the latter and the casing 3 in such a manner as to permit the passage of current from the side plate means 4, 5 to the casing 3. The joint element 1 1 is further shaped in such a manner as to block and support the side plate means 4, 5.

A supporting element 7 made of electrically insulating material, for example PVC, is provided for supporting and fixing the casing 3, the side plate means 4, 5 and the central plate means 6 to the container 2.

Inside the container 2 a reaction solution S is provided that fills the internal volume 20 until it covers completely the casing 3 and is able to react with the side plate means 4, 5 and the central plate means 6 to generate hydrogen and oxygen in gaseous form, as explained in detail further on in the description.

The reaction solution S comprises water, a non ionic surfactant containing hydrochloric acid (HC1), titanium dioxide (Ti02) in powder form, a phosphoric acid solution (H3PO4) and an acid solution containing sulphuric acid (H2SO4).

The internal volume 20 comprises an accumulation volume 21 that is not occupied by the reaction solution S and is intended to house the pressurised hydrogen and oxygen in a gaseous phase generated during the generation process.

The apparatus further comprises an inlet conduit 13 for introducing into the container 2 the components of the reaction solution S, an outlet conduit 14 to enable the hydrogen and oxygen to exit and a discharge conduit 15 for complete emptying of the container 2. A valve 25 is provided for closing or opening the discharge conduit 15.

The casing 3 has, for example, a tubular shape with a square section and comprises four side walls 31, each of which provided with one or more first openings 32 for the entry of the reaction solution S inside the casing and an upper wall 33 provided with at least a second opening 34 for the exit of the hydrogen and of the oxygen that develop in the reaction between the reaction solution S and the side plate means 5 and central plate means 6.

The side plate means 4, 5 comprises at least one passage hole 10 to enable the reaction solution S to reach the opposite sides 16, 17 of the central plate means 6. The latter comprises, in the embodiment illustrated, a single central plate 6 having a substantially elongated rectangular flat shape.

Alternatively, the central plate means 6 can comprise a plurality of central plates arranged alongside and aligned to form an elongated flat element interposed between the side plate means 4, 5.

The side plate means comprises first side plate means 4 connected to a first side 16 of the central plate 6 and second side plate means 5 connected to a second side 17 of the central plate 6.

In the embodiment illustrated, the side plate means 4, 5 comprises a plurality of side plates 8 that overlap and are alongside, each side plate 8 being provided with a respective passage hole 10.

As illustrated in particular in figure 3, the side plates 8 are grouped to form a series of blocks 9 of plates, each block 9 consisting of a plurality of side plates 8 (for example fifteen in number) combined in such a manner that the respective passage holes 10 are substantially aligned on each other and are aligned on the first openings 32 of the casing 3. The blocks 9 are arranged alongside and aligned along the opposite sides 16, 17 of the central plate 6, for example four blocks 9 aligned for each side for a total of eighty-eight side plates 8.

The side plates 8 are linked together to form the blocks 9 by means of tubes of plastic 19 inserted into the passage holes 10.

Alternatively, the side plate means 4, 5 can comprise a plurality of elongated side plates having dimensions substantially corresponding to those of the single central plate 6, the elongated side plates being grouped to form two blocks of overlapping plates that are arranged on both sides of the central plate 6.

The reaction solution S comprises:

- the phosphoric acid solution (H3P04) in a percentage comprised between 4 and 7%, in particular equal to 5.737%;

the surfactant in a percentage comprised between 0.15 and 0.20 %, in particular equal to 0.184 %

the titanium dioxide (Ti02) in a percentage comprised between 0.003 and 0.006%, in particular equal to 0.004 %;

the mineralised or demineralised water, in a percentage comprised between 45.9 and 80%, in particular comprised between 45.890 and 79.964%;

the acid solution in a percentage comprised between 14 and 48.2%, in particular comprised between 14.1 11 and 48.185%.

The surfactant comprises a hydrochloric acid (HCl)-based gel detergent in a 95% concentration by volume that includes non ionic surfactants in a 5% concentration by volume that have minimum primary biodegradability of 90%.

The phosphoric acid solution (H3P04) has a concentration by volume in distilled water comprised between 90 and 95%, in particular equal to 92%.

The acid solution comprises in water, for example demineralised water, sulphuric acid (H2S04) in a concentration by volume comprised between 25 and 45%, in particular comprised between 30 and 38%.

As explained better below in the description, the percentage volume ratio between water and acid solution, which constitute an electrolytic mixture, is established and defined by ratios determined experimentally following numerous tests.

The electrolytic mixture of water and acid solution is used and consumed in the process of generating hydrogen according to the reactions disclosed below, whereas the surfactant and the titanium dioxide take part in the process but are not substantially consumed. The phosphoric acid solution also participates in the process and in certain conditions can be consumed, as explained below.

In the internal volume 20 of the container 2 the reaction solution S occupies a volume percentage comprised between 45 and 48%, in particular equal to 47%, whilst the side plate means 4, 5 and the central plate means 6 occupy a volume percentage comprised between 20 and 23%, in particular equal to 21.6%. In this manner, in the internal volume 20 an accumulation volume 21 (in particular equal to 31.4%) remains that is not occupied by the reaction solution S and is able to receive and accumulate in pressure the hydrogen and the oxygen that are generated by the process.

Below, the chemical reactions of oxidation-reduction of the production method of the invention are explained that enable hydrogen and oxygen in gaseous form to be extracted from the water and from the acid solution introduced into the apparatus 1 by a heterogeneous catalysis process without the external supply of electric and/or thermal energy.

Whilst side plates 8 are made of zinc and/or cadmium, the central plate 6 can be made of one or more transition metals, i.e. metals belonging to the group "d" of the periodic table of the elements. Experiments and tests have been conducted using side plates of zinc and a central plate 6 made of iron, nickel and of iron and nickel alloy.

As is known, as the electronegativity of iron (1.83) measured on the Pauling scale is greater than that of zinc (1.65), iron has greater power of attraction of electrons than zinc when iron is part of a chemical bond and on the other hand zinc has greater (electropositivity) power of attraction of protons.

For both metals the standard reduction potential is:

FefsJ ;=? Fe²⁺+ 2e- -0 ,44 V (E°)

ZnfsJ ^=→ ZiT⁺+2e- -0 ,76 V (E°)

(Fe(s) and Zn(s) indicate respectively iron and zinc in solid state)

As the two metals (the side plates 8 and the central plate 6) are assembled and are in contact with one another inside the casing 3, the potential difference between the two metals is:

fa d.c/.p = E^:( Fe²⁺ Fe ) - E° ( Zii²⁺" Zn) =^■ 0,44- (-0,76) = 0,32V

In particular, between the side plates 8 and the central plate 6 the electric charge is circulated according to the relations:

Fefs) Fe²⁺+ 2e- Zn(s) Zn²⁺+2e-

Fe \ Ζ ) ^=→ FefsJ +Zn²⁺

2+

the charge circulation enables the iron (Fe ) to give protons to the zinc and consequently

2- .

the zinc (Zn ) gives electrons to the iron. The two metals joined by contact form polarisation by orientation.

If the central plate 6 is made of nickel the standard reduction potentials are:

N%$) i=? Ni²⁺ + 2e- -0,257 V (E°)

Zn(s)→ Zn²⁺ + 2e- -0,76 V (E°)

The potential difference between the two metals is:

la d.d.p = E°(Ni²⁺/ s))- E° ( Zu^z+/ Zn(s)) = (-0,257}- (- ΰ,16)= β,50 V

whilst the electric charge circulates according to the relations:

M²⁺+ Ζ ) ϊ=ί Mi(s) ₊Zii²⁺

If the central plate 6 is made of iron and nickel alloy, the standard reduction potentials are: Ζφ) ^=→ Zn²⁺+2e- -0 ,76 V (E°)

efsJ i=? Fe²⁺+ 2e- -0,44 V (E°)

ϊ=? M²⁺ + 2e- -0,257 V (E°)

The potential difference between the three metals is:

la d.d.p = EW²⁺/ M j;- E^a (Ζη²⁺' Z/f(s) = f-< 57/- {- 0,76)= 0,50 V

a ddp = E°i Fe²7 Fe ) - E° ( Zn²⁺/ Zn) =^■ 0,44- (-0,76) = 0,32V

The total potential difference is the sum of the partial potential differences and is 0.82 V. In the processes disclosed below the metal plates immersed in the reaction solution S act as electrodes owing to the fact that they are placed in contact with on another. In particular, the central plate 6 made of iron and/or nickel acts as a cathode (positive electrode) whilst the side plates 8 made of zinc act as an anode (negative electrode).

The function of the casing 3 is to become electrified in such a manner as to charge with negative ionic energy, by the joint element 1 1 creating a "Faraday cage effect" that has the function of accelerating the negative ions forced to pass into the passage holes 10 of the

+

side plates 8 and of attracting the hydronium ions (H3O ) inside the casing 3.

In the electrolytic mixture consisting of water and acid solution, the water can be demineralised (distilled) or mineralised. In the latter case, the dissolved substances that constituted the fixed residue, are inert and do not take part in the chemical reactions set out below.

In the electrolytic mixture consisting of water and acid solution containing sulphuric acid (H2SO4) the following reaction occurs:

H₂S0₄ ⁺ H₂0—► H₃0⁺+ HSO^'

The sulphuric acid is a polyprotic acid, i.e. an acid that can dissociate several times.

The electrolytic mixture inside the container 2 will determine the following behaviours of the side 8 and central 6 metallic plates. The ions HS04^" deriving from the dissociation of the sulphuric acid move to the side plates 8 of zinc, causing the following reactions:

Ζιψή + H₂S0₄ ⁺ H₂0 ► H₃ Q + Z_/iSi¾ + H

As

Zn²⁺+ ZflS ^'— > Zn$Q_A

there is also:

Zn²⁺+ ZnSQ^ ^'—►ZfiSq,^"

and thus

ZnS0₄ ^"— > Z/iS(¾+ e

There is thus a passage of electrons (e) that through contact are transmitted by the side plates 8 of zinc to the central plate 6 of iron and/or nickel.

The hydronium ions H3O deriving from the dissociation of the sulphuric acid move to the central plate 6 of iron and/or nickel charged negatively by the electrons coming from the side plates 8 made of nickel, causing the following reactions

₊ Ν $}οΡ )

2 H₃0 ⁺2e- ^► 3 H₂ + 20

It should be noted that the iron and/or nickel of the central plate 6 does not participate in the reaction and does not undergo molecular modification, but acts as a catalyst, i.e. it enables the dissociation of the hydronium ions via heterogeneous catalysis.

After the passage of electrons, the central plate 6 made of iron and/or nickel becomes the cathode, i.e. the positive electrode in which the negative reduction process occurs, whilst the side plates 8 made of zinc are after electronic migration the negative anode, i.e. the electrode in which the positive oxidation process occurs.

It should be noted that experimental tests have shown that introducing titanium dioxide in powder form into the reaction solution S prevents sulphation of the side plates 8 made of zinc, i.e. the accumulation on the surfaces of the latter of zinc sulphate ZnSC>4 ^tnat would hinder and gradually prevent the progress of oxidation-reduction reactions disclosed above. Owing to the action of the titanium dioxide the zinc sulphate precipitates to the bottom of the container together with the fixed residue that may have accumulated and rises from the scission of the water.

The reaction solution S further contains a gel detergent based on 95% hydrochloric acid (HC1) concentration, consisting of a 5% non ionic surfactant.

The role of this compound is the following.

When the hydrochloric acid HC1 (monoprotic acid) is dissolved in water it has the following dissociation reaction: When said acid comes into contact with the side plates 8 of zinc the following reaction occurs:

2HC1 + H₂0 + Zn(s)→ H₃0⁺ + ZnCl₂ ^" + H

as

ZnCi— >Zn²⁺+ C/^{3 *}

we have:

ZnC/+ e

The zinc chloride (Ζη0₂) -then releases electrons that through contact are transmitted by the side plates 8 of zinc to the central plate 6 of iron and/or nickel.

In the electrolytic dissociation in the mixture with water the hydrochloric acid (HC1) forms hydronium ions Η3<_ ⁺ and in contact with the side plates of zinc supplies the electronic flow transmitted to the central plate of iron and/or nickel.

Also in this case experimental tests have shown that the presence of titanium dioxide in powder form in the reaction solution S enables the zinc chloride to precipitate to the bottom of the container, preventing the accumulation thereof on the surfaces of the side plates 8.

The reaction solution S further contains a phosphoric acid solution (H3PO4) in a 92% concentration by volume with distilled water.

As the phosphoric acid is polyprotic, i.e. has the ability to dissociate electrolytically at least three times, it is used to generate hydronium ions H3O and accelerate the reaction, in particular in an initial activation step.

It should be noted that if in the reaction solution S the quantity of electrolytic solution (water and acid solution of sulphuric acid H2SO4+H2O) is lacking, the phosphoric acid will tend to react with the side plates 8 made of zinc according to the reaction:

Ζ ) ⁺2W₂0 +H₃PQ₄— H₃0⁺+Z«Pi¾²÷ H

and will thus be progressively consumed and will have to be restored. In particular, the zinc phosphate (ZnPC^), like the zinc sulphate, will precipitate to the bottom of the container without accumulating on the side plates owing to the action of the titanium dioxide.

The function of the non ionic surfactant is very important, because when it is solubilised in the electrolytic mixture it has the function of increasing the interaction distance between the molecules of the water and the positive and negative ions that form in the mixture, promoting the catalysis reaction. Further, experimental tests have shown that in cooperation of titanium oxide, the surfactant prevents the accumulation on the surfaces of the side plates 8 of zinc sulphate (ZnSC^«4), zinc phosphate (ZnPC^) and zinc chloride (ZnCl₂).

As already shown, the central plate 6 can be made using one or more of the transition metals belonging to sector "d" of the periodic table of the elements. The iron and the nickel can then be replaced or cooperate with other elements such as chromium, cobalt, copper, molybdenum, technetium, ruthenium, rhodium, palladium, silver, cadmium, tungsten, rhenium, osmium, iridium, platinum, gold and mercury.

As all these elements behave as oxidants in contact with zinc (reducing element), they will allow better or worse electronic migration and consequently the catalysation of the hydronium ions in the electrolytic mixture.

To summarise, on the central plate 6 that acts as a catalyst and is made of a transition metal x or of a plurality of transition metals∑x there will be the following reaction:

2 W₃0⁺÷ 2e 3 H_{2 +} 20

(rel. A)

On the side plates 8 made of zinc there will be the following reactions:

Ζφ) * H₂S0₄ * H₂0—► H₃0 + ZnS<¾ + H

2HC1 + H₂0 + Zn(s)→ H₃0⁺ + ZnCl₂ ^~ + H (rel. B)

Further, on the side plates 8 there may be the reaction if the quantity of electrolytic solution has not been restored during the process.

H₂S0₄ ⁺ H₂.Q—► ₃0⁺+ HSO^' If, on the other hand, this quantity of electrolytic solution is maintained constant, the following reaction is obtained:

H₂0 ₊H₃PO→ Η₃0 + Ρ0 + 2Η ^

From the reactions disclosed above gaseous molecular hydrogen (H₂), monoatomic hydrogen (H), and gaseous molecular oxygen (0₂) will be released according to the relations A, B, C specified above in the quantity 3H₂+0₂+4H.

As the container 2 is maintained at a pressure comprised between 2 and 3.5 bar, the monoatomic hydrogen (H) will tend to be reabsorbed by the electrolytic mixture and will make a large contribution to ionic dissociation, enabling the speed of reaction and production of the gas to be increased.

The operation of the apparatus 1 and the method for using this apparatus to generate hydrogen and oxygen in a gaseous phase provide an initial starting step required to activate the electrochemical reactions.

Inside the previously opened container 2 or through the inlet conduit 13, the following is introduced in sequence to form the reaction solution S:

the titanium dioxide (T1O2) in a volume percentage comprised between 0.003 and 0.006%, in particular equal to 0.004 %;

the phosphoric acid solution (H3PO4) in a volume percentage comprised between 4 and 7%, in particular equal to 5.737 %;

the mineralised or demineralised water, in a volume percentage comprised between 45.9 and 80%, in particular comprised between 45.890 and 79.964%;

the acid solution in a volume percentage comprised between 14 and 48.2%, in particular comprised between 14.11 1 and 48.185%, and containing sulphuric acid (H2SO4) and the non ionic surfactant containing hydrochloric acid (HC1) and in a volume percentage comprised between 0.15 and 0.20 %, in particular equal to 0.184%. The water and the acid solution form the electrolytic solution from which to extract, by the oxidation-reduction processes disclosed above, hydrogen and oxygen in gaseous form. Numerous tests have shown that it is necessary to introduce the water into the apparatus always before the acid solution and the surfactant to control the electrochemical reactions. In one production operating step, the reaction solution S must be integrated progressively and in particular the electrolytic solution that is consumed by dissociation, by delivering water and the acid solution according to a preset volume percentage.

The experimental data are set out below that were obtained by using an apparatus 1 having the features and dimensions set out below.

The side plate means 4, 5 comprises 88 side plates 8 made of zinc, each square side plate 8 measuring 10x10x0.4 cm.

The central plate means 6 comprises a single central plate made of nickel measuring 10x40x1.2 cm.

3

The total volume occupied by all the assembled plates is 4 dm .

3

The volume occupied by joint element 1 1 made of zinc is 0.080 dm .

The tubular casing made of stainless steel has a side square section of 12.6 cm, wall thickness 0.3 cm and height of 50 cm with an occupied volume of 0.781 dm3.

The container 2 has a cylindrical shape with an internal diameter of 18 cm and an internal

3 height of 73 cm. The internal volume 20 of the container 2 is thus equal to 18.55 dm .

The components of the reaction solution S are introduced according to the following quantities in volume:

titanium dioxide (Ti02) in powder form: 1.5 g;

3

surfactant: 0.016 dm

3

- phosphoric acid solution (H3P04); 0.5 dm ;

3

water and acid solution (electrolytic solution): 8.2 dm . As the titanium dioxide has a density of 4.23 g/cm the introduced volume is equal to

3 3 about 0.0004 dm The total volume of the reaction solution S is thus 8.7164 dm

The components of the electrolytic solution, i.e. the acid solution of sulphuric acid and water, have to be introduced in preset ratios. Tests have been conducted with the following volume ratios:

The ratio (a) is the quantity of acid solution necessary for the first activation, i.e. the minimum quantity of acid solution necessary for activating the reaction.

The table shows how, by increasing the quantity of acid solution in relation to water, the speed reaction and generation (volume) of hydrogen and oxygen increase.

The gas (hydrogen and oxygen) generated by the reaction accumulates in the internal volume 20 in which the accumulation volume 21 not occupied by the reaction solution S is provided for the purpose. Inside this accumulation volume 21 the gas is maintained at an operating pressure between 2 and 3.5 bar. This operating pressure both enables the monoatomic hydrogen (H) developing in the reactions to be reabsorbed by the electrolytic mixture and prevents the non ionic surfactant from foaming and ensures the stability of the hydrogen and oxygen generation process.

Continuity of generation is ensured by pressurised delivery of water and acid solution in the previously chosen proportions.

The reactions can be stopped by interrupting hydrogen generation, by removing the metal plates from the apparatus 1 or emptying the reaction solution S from the container via the discharge conduit 15. The pressure of the gas inside the container 2 enables the solution to exit.

Owing to the apparatus and method of the invention it is thus possible to produce hydrogen and oxygen by using an electrolytic solution consisting of water and acid solution by means of an electrolytic process of heterogeneous catalysis without the need to supply external energy (electric and/or thermal) both during the step of activating chemical reactions and in the production step.

The apparatus 1 enables large quantities of hydrogen to be generated from components (water, sulphuric acid, hydrochloric acid, phosphoric acid, surfactant) that are easily found on the market and are cheap.

The gas obtained consisting of hydrogen and oxygen can be used directly to supply internal combustion engines, boilers, fuel cells or other chemical/energy processes.

The apparatus of the invention is particularly compact because it comprises a container that can be transported and positioned on the premises of the end users. Further, it can be sized according to the specific hydrogen requirements to be meet limited needs (for example for domestic use) or larger-scale needs (electric power plants).

It should be observed that the apparatus and the method of the invention are not pollutant and harmful to the environment because they do not cause the production of toxic and harmful by products and generate gases (hydrogen and oxygen) that can be burnt completely.

The precipitates of zinc sulphate (ZnSC>4), zinc phosphate (ZnPC^) and zinc chloride (ZnCl2) can be easily recovered and reused in different productive cycles.

Lastly, the electrochemical reactions that develop inside the apparatus 1 are only exothermic and develop little heat. Tests conducted have shown an increase of about 10- 20°C compared to the temperature of the apparatus that is not in operation (ambient (temperature).

Claims

Apparatus for generating hydrogen and oxygen comprising:

- a container

(2) made of electrically insulating material and defining an internal volume (20);

- a casing (3) made of electrically conductive metal material, inserted into said internal volume (20);

- side plate means (4, 5) made of zinc and/or cadmium metal alloy and fixed in contact with opposite sides (16, 17) of central plate means (6) made of metal alloy containing one or more transition metals, in particular iron and/or nickel, said side plate means (4, 5) and said central plate means (6) being housed inside said casing (3), said side plate means (4, 5) being in electrical connection with said casing (3);

- a reaction solution (S) arranged for filling said internal volume (20) until it covers completely said casing (3) and arranged for interacting with said side plate means (4, 5) and said central plate means (6) for generating hydrogen and oxygen in gaseous form, said reaction solution comprising water, a non ionic surfactant containing hydrochloric acid (HC1), titanium dioxide (T1O2) in powder form, a phosphoric acid solution (H3PO4) and an acid solution containing sulphuric acid (H₂S0₄).

Apparatus according to claim 1, wherein said reaction solution (S) interacts with said side plate means (4, 5) and said central plate means (6) according to the following electrochemical reactions:

₊ x o∑x

2H₃0 ÷2e ► 3H₂ + 2Q

(rel. A)

on said central plate means (6) made of a transition metal (x) or of a plurality of transition metals (∑x);

Ζφ) ⁺ W₂S0₄ ⁺ H₂.0—► tf₃ o⁺+ Zff Si¾ + H

2HC1 + H₂0 + Zn(s)→ H₃0⁺ + ZnCl₂ ^" + H (rel. B)

on said side plate means (4, 5) made of zinc;

Η₂0 ₊Η₃Ρί¾-→ H₃Q + PO; +lH ^ _Q

in the reaction solution (S);

said electrochemical reactions liberating gaseous molecular hydrogen (¾), monoatomic hydrogen (H), and gaseous molecular oxygen (0₂).

Apparatus according to claim 1 or 2, wherein said casing

(3) is made of stainless steel and comprises at least one side wall (31) provided with at least a first opening (32) for the entry of said water solution and an upper wall (33) provided with at least a second opening (34) for the exit of said hydrogen and said oxygen.

4. Apparatus according to any preceding claim, comprising a supporting element (7) made of electrically insulating material arranged for supporting and fixing said casing (3) and said side plate means (4, 5) to said container (2).

5. Apparatus according to any preceding claim, wherein said side plate means (4, 5) comprises at least one passage hole (10) to enable said reaction solution (S) to reach the opposite sides (16, 17) of said central plate means (6).

6. Apparatus according to claim 5, wherein said central plate means comprises a single central plate (6), in particular having a flat elongated substantially rectangular shape.

7. Apparatus according to any preceding claim, wherein said side plate means comprises first side plate means (4) connected to a first side (16) of said central plate means (6) and second side plate means (5) connected to a second side (17) of said central plate means (6).

8. Apparatus according to any preceding claim, wherein said side plate means (4, 5) comprises a plurality of side plates (8) that overlap and are alongside, each side plate (8) being provided with a respective passage hole (10).

9. Apparatus according to claim 8, wherein said side plates (8) are grouped to form a series of blocks (9), each block (9) consisting of a plurality of side plates (8) connected in such a manner that the respective passage holes (10) are substantially aligned, said blocks (9) being arranged alongside and aligned along the opposite sides (16, 17) of said central plate means (6).

10. Apparatus according to any preceding claim, comprising a joint element (1 1) made of zinc metal alloy and placed in contact with said side plate means (4, 5) and interposed between the latter and said casing (3) in such a manner as to permit the passage of current from said side plate means (4, 5) to said casing (3).

11. Apparatus according to claim 10, wherein said passage of current from said side plate means (4, 5) to said casing (3) enables the latter to become electrified and charged with negative ionic energy, creating a "Faraday cage effect" that has the function of accelerating negative ions contained in the reaction solution (S) and of attracting the hydronium ions (H3O ) inside the casing (3).

12. Apparatus according to any preceding claim, wherein said reaction solution (S) comprises:

phosphoric acid solution (H3PO4) in a volume percentage comprised between 4 and 7%, in particular equal to 5.737 %;

non ionic surfactant comprising hydrochloric acid (HC1) and in a volume percentage comprised between 0.15 and 0.20 %, in particular equal to 0.184 % titanium dioxide (T1O2) in a volume percentage comprised between 0.003 and 0.006%, in particular equal to 0.004 %;

water in a volume percentage comprised in particular between 45.9 and 80%, in particular comprised between 45.890 and 79.964%.

acid solution containing sulphuric acid (H2SO4) and in a volume percentage comprised between 14 and 48.2%, in particular comprised between 14.1 11 and 48.185%.

13. Apparatus according to any preceding claim, wherein said surfactant comprises a gel detergent based on a 95% hydrochloric acid (HC1) concentration by volume that includes non ionic surfactants in a concentration by volume of 5% that have 90% minimum primary biodegradability.

14. Apparatus according to any preceding claim, wherein said phosphoric acid solution (H3PO4) has concentration by volume in distilled water comprised between 90 and 95%, in particular equal to 92%.

15. Apparatus according to any preceding claim, wherein said acid solution comprises sulphuric acid (H2SO4) that has concentration by volume in water comprised between 25 and 45%, in particular comprised between 30 and 38 %.

16. Apparatus according to any preceding claim, wherein in said internal volume (20) said reaction solution (S) occupies a volume percentage comprised between 45 and 48%, in particular equal to 47%, and said side plate means (4, 5) and central plate means (6) occupy a volume percentage comprised between 20 and 23%, in particular equal to 21.6%.

17. Apparatus according to any preceding claim, wherein said internal volume (20) comprises an accumulation volume (21) not occupied by said reaction solution (S) and intended for housing said hydrogen and said oxygen in gaseous form.

18. Apparatus according to any preceding claim, comprising an inlet conduit (13) for introducing into said container (2) at least said water and said acid solution, an outlet conduit (14) to enable pressurised hydrogen and oxygen to exit and a discharge conduit (15) for complete emptying of said container (2).

19. Method for generating hydrogen and oxygen using an apparatus (1) according to any preceding claim, comprising in an initial step introducing into the apparatus (1) in sequence so as to form a reaction solution (S):

titanium dioxide (T1O2) in a volume percentage comprised between 0.003 and 0.006%, in particular equal to 0.004 %;

a phosphoric acid solution (H3PO4) in a volume percentage comprised between 4 and 7%, in particular equal to 5.737 %;

water in a volume percentage comprised between 45.9 and 80%, in particular comprised between 45.890 and 79.964%;

an acid solution in a volume percentage comprised between 14 and 48.2%, in particular comprised between 14.111 and 48.185%, and containing sulphuric acid (H2SO4) and a non ionic surfactant containing hydrochloric acid (HC1) and in a percentage comprised between 0.15 and 0.20 %, in particular equal to 0.184 %. Method according to claim 19, comprising integrating said reaction solution (S) during a hydrogen and oxygen generation operating step by introducing water and acid solution according to a preset proportion.