Electrolysis System and Method for a High Electrical Energy Transformation Rate

Abstract

The invention relates to an electrolysis system to conduct oxidation and reduction reactions, comprising one or more electrolytic cells, with each one of them being formed by at least a pair of electrodes and an electrolyte provided between said electrodes, wherein the assembly of said one or more electrolytic cells defines an electrolyzer; and an energy source that supplies an electrical signal to the electrolyzer; wherein said electrolytic cell is built in the form of a capacitor of cylindrical plates, wherein said cylindrical plates are defined by the electrodes of the electrolytic cell formed by tubes arranged in a substantially concentric way within each other, thus defining a central electrode, an outer electrode and a space between electrodes, wherein the central electrode corresponds to the anode of the capacitor, the outer electrode to the cathode of the capacitor and the electrolyte to the dielectric means of the capacitor; wherein the electrical signal received by the electrolytic cell or cells that form the electrolyzer correspond to a direct current pulse, wherein said pulse is configured for each electrolyzer's electrolytic cell to operate: In a charge transient regime of each cell during the current pulse; and In a discharge transient regime of each cell during the time between current pulses; wherein said charge and discharge transient regimes are defined by the construction of each electrolytic cell in the form of a cylindrical plates capacitor. In addition, the invention also relates to associated method and uses.

Claims

1-37. (canceled)

38. An electrolysis system to conduct oxidation and reduction reactions, comprising: electrolytic cells, with each one of them being formed by at least a pair of electrodes and an electrolyte provided between said electrodes, wherein the assembly of said electrolytic cells defines an electrolyzer, and wherein the electrolyzer comprises two or more groups of electrolytic cells; an energy source that supplies an electrical signal to the electrolyzer; and a control unit connected to the energy source or to one or more switches arranged between the energy source and the electrolyzer, providing a sequential supply of the electrical signal, distributing the electrical signal over a first group of electrolytic cells for a certain time and once said time is ended, distributing the electrical signal over a second group of electrolytic cells for a certain time, thus generating the direct current pulse over each group of electrolytic cells within the period (T) of the current pulse; wherein said electrolytic cells are built in the form of a capacitor of cylindrical plates, wherein said cylindrical plates are defined by the electrodes of the electrolytic cells formed by tubes arranged in a substantially concentric way within each other, thus defining a central electrode, an outer electrode and a space between electrodes, wherein the central electrode corresponds to the anode of the capacitor, the outer electrode to the cathode of the capacitor and the electrolyte to the dielectric means of the capacitor; wherein the electrical signal received by the electrolytic cells that form the electrolyzer correspond to a direct current pulse having a frequency (f) and a period (T), wherein said pulse is configured for each electrolyzer's electrolytic cell to operate: in a charge transient regime of each cell during the current pulse; and in a discharge transient regime of each cell during the time between current pulses; wherein said charge and discharge transient regimes are defined by the construction of each electrolytic cell in the form of a cylindrical plates capacitor; wherein the direct current pulse comprises such an amplitude, duration and frequency that each electrolytic cell of the electrolyzer is energized in its corresponding charge and discharge transient regimes.

39. The system according to claim 38, wherein the central electrode is a hollow cylindrical electrode that defines an inner space, wherein the reduction reaction takes place over the inner side of the outer electrode and the oxidation reaction takes place over the outer side of the central electrode, wherein the oxidation reaction also takes place alternatively over the inner side of the central electrode, wherein it also comprises one or more extraction ducts of the oxidation reaction product, wherein each of said ducts is in communication with the inner space of the central electrode, and wherein it also comprises one or more extraction ducts of the reduction reaction product, wherein each of said ducts is in communication with the space between electrodes.

40. The system according to claim 38, wherein the current pulse has an amplitude defined by a maximum or peak voltage of the energy source (V.sub.max), and an effective average voltage (V.sub.average), wherein said effective average voltage is defined as the optimum voltage that favors the production of the electrolytic cell, known as cell potential, and wherein the direct current pulse has a duration defined by a factor of direct current pulse duration (D) or working cycle, in relation to the period (T) of said pulse, wherein the direct current pulse duration corresponds to the product between D and T, wherein the working cycle D is defined by the following relation: ${D\left(\frac{V_{\mathrm{average}}}{V_{\max }}\right)}^2.$

41. The system according to claim 38, wherein the direct current pulse has a frequency (f) or period (T) defined as: $T=\frac{1}{f}=\mathrm{RC}*\ln \left(\frac{V_{\mathrm{cell}}\left(T\right)}{V_{\mathrm{cell}}\left(\mathrm{DT}\right)}\right)$ wherein RC is the time constant representing the capacitive and resonant behavior of the electrolytic cell, V.sub.cell(T) is the voltage of each electrolytic cell when t=T, before receiving a new direct current pulse during the discharge of the capacitor, wherein V.sub.cell(DT) is the voltage of the electrolytic cell when t=DT when the current pulse ends during the charge of the capacitor.

42. The system according to claim 40, wherein the direct current pulse generates an effective average current flow circulating through each electrolytic cell, wherein said current flow is defined as: $I_{\mathrm{average}}=\frac{f}{V_{\max }*\sqrt{D}}.Math.\left\{\frac{1}{2}.Math.C\left[{\left(V_{\mathrm{cell}}\left(\mathrm{DT}\right).Math.\left(1-e^{-\frac{D/f}{\mathrm{RC}}}\right)+V_{\mathrm{cell}}\left(T\right)\right)}^2-{V_{\mathrm{cell}}\left(T\right)}^2\right]\right\}.$

43. The system according to claim 38, wherein said control unit operates the energy source in order to provide the direct current pulse received by the electrolytic cells of the electrolyzer.

44. The system according claim 38, wherein said control unit operates the activation and deactivation of each switch by controlling the duration and frequency of the current pulse received by the electrolytic cells of the electrolyzer, wherein the control unit activates and deactivates the switches supplying the electrical signal provided by the energy source sequentially, distributing the electrical signal over the first and second groups of electrolytic cells, wherein each group is formed by two or more electrolytic cells connected in series and where said time determined corresponds to the pulse duration.

45. The system according to claim 38, wherein said groups of electrolytic cells are connected in parallel.

46. The system according to claim 39, wherein the central electrode comprises one or more openings in its surface that communicate the space between electrodes with the inner space of the central electrode, with said openings allowing the free circulation of the electrolyte between said space between electrodes and the inner space of the central electrode, wherein the opening(s) of the central electrode are provided to allow the product of the oxidation reaction to circulate from the outer side of the central electrode to the inner space of the central electrode.

47. The system according to claim 46, wherein the openings are located in different zones of extraction of the central electrode, with said extraction zones being distributed along at least one portion of said electrode, where each zone of extraction comprises at least one stopping device arranged over the outer side of the central electrode, wherein said stopping device prevents the circulation of the product of the oxidation reaction over the outer side of the central electrode, conveying said product to the inner space of the central electrode through the holes or openings, wherein the stopping device(s) extend in the space between electrodes, leaving a circulation space for the electrolyte near the inner side of the outer electrode, wherein said circulation space is provided for the free circulation of the product of the reduction reaction.

48. The system according to claim 38, wherein the central electrode is surrounded by a separation mesh.

49. The system according to claim 38, wherein the electrolytic cells are vertically arranged and operated at atmospheric pressure, wherein the electrodes making up the cells are formed by hollow vertical tubes.

50. An electrolysis method to perform the oxidation and reduction reactions, comprising: providing an electrolysis system, comprising: electrolytic cells, with each one of them being formed by at least a pair of electrodes and an electrolyte provided between said electrodes, wherein the assembly of said electrolytic cells defines an electrolyzer, and wherein the electrolyzer comprises two or more groups of electrolytic cells; an energy source that supplies an electrical signal to the electrolyzer; and a control unit connected to the energy source or to one or more switches arranged between the energy source and the electrolyzer; wherein said electrolytic cells are built in the form of a capacitor of cylindrical plates, wherein said cylindrical plates are defined by the electrodes of the electrolytic cells formed by tubes arranged in a substantially concentric way within each other, thus defining a central electrode, an outer electrode and a space between electrodes, wherein the central electrode corresponds to the anode of the capacitor, the outer electrode to the cathode of the capacitor and the electrolyte to the dielectric means of the capacitor; applying a direct current pulse over the electrolytic cells) forming the electrolyzer of the electrolysis system, said current pulse having a frequency (f) and a period (T); controlling the energy source or the one or more switches arranged between the energy source and the electrolyzer, providing a sequential supply of the electrical signal, distributing the electrical signal over a first group of electrolytic cells for a certain time and once said time is ended, distributing the electrical signal over a second group of electrolytic cells for a certain time, thus generating the direct current pulse over each group of electrolytic cells within the period (T) of the current pulse; configuring said direct current pulse for each electrolytic cell of the electrolyzer to operate: under a charge transient regime of each cell for the time of duration of the current pulse, and under a discharge transient regime of each cell for the time between current pulses; wherein said transient regimes of charge and discharge are defined by the construction of each electrolytic cell in the form of a cylindrical plates capacitor, wherein the step of configuring the direct current pulse comprises determining an amplitude, duration and frequency of said pulse such that each electrolytic cell of the electrolyzer is energized in its corresponding charge and discharge transient regimes.

51. The method according to claim 50, wherein the step of configuring the direct current pulse comprises the definition of an amplitude for said pulse by a maximum or peak voltage of the energy source (V.sub.max), and an effective average voltage (V.sub.average), wherein said effective average voltage is defined as the optimum voltage that favors the production of the electrolytic cell, known as cell potential, and wherein the step of configuring the direct current pulse comprises the definition of the duration of said pulse by a factor of direct current pulse duration (D) or working cycle, in relation to the period (T) of said pulse, wherein the direct current pulse duration corresponds to the product between D and T, wherein the working cycle D is defined by the following relation: ${D\left(\frac{V_{\mathrm{average}}}{V_{\max }}\right)}^2.$

52. The method according to claim 50, wherein the step of configuring the direct current pulse comprises the definition of a frequency (f) or period (T) of the pulse defined as: $T=\frac{1}{f}=\mathrm{RC}*\ln \left(\frac{V_{\mathrm{cell}}\left(T\right)}{V_{\mathrm{cell}}\left(\mathrm{DT}\right)}\right)$ wherein RC is the time constant representing the capacitive and resonant behavior of the electrolytic cell, V.sub.cell(T) is the voltage of each electrolytic cell when t=T, before receiving a new direct current pulse during the discharge of the capacitor, and wherein V.sub.cell(DT) is the voltage of the electrolytic cell when t=DT when the current pulse ends during the charge of the capacitor.

53. The method according to claim 51, wherein the step of configuring the direct current pulse comprises applying an average effective current flow circulating through each electrolytic cell defined by: $I_{\mathrm{average}}=\frac{f}{V_{\max }*\sqrt{D}}.Math.\left\{\frac{1}{2}.Math.C\left[{\left(V_{\mathrm{cell}}\left(\mathrm{DT}\right).Math.\left(1-e^{-\frac{D/f}{\mathrm{RC}}}\right)+V_{\mathrm{cell}}\left(T\right)\right)}^2-{V_{\mathrm{cell}}\left(T\right)}^2\right]\right\}.$

54. The method according to claim 50, wherein the step of controlling the energy source provides the direct current pulse received by the electrolyzer's electrolytic cells.

55. The method according to claim 50, wherein the step of controlling the activation and deactivation of one or more switches arranged between the energy source and the electrolyzer controls the duration and frequency of the current pulse received by the electrolyzer's electrolytic cells, activating and deactivating the switches supplying the electrical signal provided by the energy source sequentially, distributing the electrical signal over the first and second groups of electrolytic cells, wherein each group is formed by two or more electrolytic cells connected in series and where said time determined corresponds to the pulse duration.

56. The method according to claim 50, further comprising the step of extracting a product of the oxidation reaction through one or more ducts, wherein each of those ducts is in communication with the inner space of the central electrode, and wherein it also comprises the step of extracting a product of the reduction reaction through one or more ducts, wherein each of those ducts is in communication with the inner space of the central electrode.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0080] As part of the present application the following figures are shown, which are representative of the invention and teach a preferred embodiment thereof; therefore, they should not be construed as limiting the definition of the matter claimed by the present application.

[0081] FIGS. 1a and 1b show charts for the behavior of the voltage signal obtained from the current supply side and for the behavior of the voltage signal from the electrical charge, respectively.

[0082] FIGS. 2a and 2b show schemes of the electrolysis system according to embodiments of the invention.

[0083] FIG. 3 shows a cross-section view of the electrodes of the electrolytic cell according to an embodiment of the invention.

[0084] FIG. 4 shows a cross-section view of a lower section of an electrolytic cell according to an embodiment of the invention.

[0085] FIG. 5 shows a cross-section view of a lower section of two electrolytic cells according to an embodiment of the invention.

[0086] FIG. 6 shows a cross-section view of an upper section of an electrolytic cell according to an embodiment of the invention.

[0087] FIG. 7 shows a perspective view of the electrolysis system according to an embodiment of the invention.

[0088] FIG. 8 shows a perspective view of an electrolysis plant according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0089] FIGS. 1a and 1b show voltage versus time charts showing the behavior of the electrical signal both on the supply side (FIG. 1a) and on the electrical charge side, i.e. on the electrolytic cell side (FIG. 1b). As evidenced from FIG. 1a, the form of the voltage signal on the supply side reflects the pulsing nature of the current, showing a maximum voltage (V.sub.max) that is kept for the duration () given by the D*T product, wherein D is the duration factor of the current pulse and T is the pulsing wave period. Therefore, the distribution of current delivered by the energy source is shown in a scheme of current intervals over each electrolytic cell, showing a maximum voltage during part of the wave period and null voltage during the remaining part of said period. Additionally, FIG. 1b reflects that during the part of the wave period where the maximum voltage is delivered, each electrolytic cell formed by the electrolysis system reaches a cell voltage V.sub.cell(DT) given by the cell charge acting as capacitor when t=DT.

[0090] In the chart of FIG. 1b it can be also seen that once the duration of the current pulse endsin the step where the voltage delivered by the source is nullthe electrolytic cell starts its discharge phase, which ends with the termination of the wave period and the start of a new pulse, when t=T. At this time, the cell voltage is given by V.sub.cell(T). The equations ruling the charge and discharge processes of the capacitor in terms of cell voltage are:

[00012]$\mathrm{Charge}.Math..Math.\left(\mathrm{rise}\right).Math.\text{:}$$V_{\mathrm{cell}}\left(t\right)=V_{\mathrm{cell}.Math..Math.\max }*\left(1-e^{\frac{-t}{\mathrm{RC}}}\right)$$\mathrm{Discharge}.Math..Math.\left(\mathrm{drop}\right).Math.\text{:}$$V_{\mathrm{cell}}\left(t\right)=V_{\mathrm{cell}.Math..Math.\max }*e^{\frac{-t}{\mathrm{RC}}}$

[0091] FIG. 2a shows a scheme of an electrolysis system 10 according to an embodiment of the invention comprising an energy source 11 and an electrolyzer. The electrolyzer comprises a first electrolytic cell 13.1 formed by concentric cylindrical electrodes. Under this embodiment, the energy source 11 provides an electrical signal composed of a pulsing current wave according to the invention, which signal is received by the first electrolytic cell 13.1 of the electrolyzer 12. Said signal comprises such an amplitude, duration and frequency that the first electrolytic cell 13.1 operates in a charge and discharge transient regime according to its design characteristics. FIG. 2a also shows that the electrolyzer 12 can comprise a second optional electrolytic cell 13.2 connected in series with the first electrolytic cell 13.1 in this case. Under this embodiment the energy source 11 should be designed for the amplitude of the pulsing current wave may ensure that both the first and the second electrolytic cells 13.1, 13.2 operate in charge and discharge transient regimes. Considering that both cells are connected in series in this case, the operation thereof will be simultaneous. If both cells 13.1, 13.2 are identical, the distribution of the voltage provided by the energy source 11 will be equitable with both cells operating in an equivalent form. Here it is important to note that if additional electrolytic cells are connected in series, the energy source 11 shall be sized in order to contribute the necessary energy to operate all cells in series at the same time.

[0092] Additionally, FIG. 2b shows a scheme of an electrolysis system 10 comprising an energy source 11, an electrolyzer 12, a control unit 15 and at least one switch 16.1. The electrolyzer 12 comprises a first set of electrolytic cells 14.1, where said set formed by two or more electrolytic cells according to the invention is connected in series. Under this embodiment, the energy source 11 can be a direct current source providing direct current of a certain strength and amplitude in order to operate the first set of electrolytic cells 14.1. The control unit 15 is configured in such a way to control the activation or deactivation of a first switch 16.1 connected to the first set of cells, where said switch is in charge of applying the current pulse over the first set of cells 14.1 when opening or closing the circuit. By the activation and deactivation of the first switch 16.1 the current pulse supplying the electrolytic cells connected in series of the first set of cells 14.1 is generated. According to another embodiment, the electrolysis system 10 can comprise a second set of electrolytic cells 14.2 connected in parallel to the first set of cells 14.1, with said second set being formed in an equivalent form to the first set. According to this embodiment, the electrolysis system 10 also comprises a second switch 16.2 connected to the second set of cells in charge of operating in a similar form to that of the first switch, but in relation to the second set of cells 14.2. According to this embodiment, the control unit 15 coordinates the activation and deactivation of the first and second switches 16.1 and 16.2 for the first and second sets of cells 14.1 and 14.2 operate sequentially, taking advantage of the connection in parallel to one single energy source 11. Thus, the same energy source 11 sized in order to provide current voltage and flow to operate a set of cells in series can be operated to supply two sets of cells connected in parallel, where in first place the first switch 16.1 is activated in order to operate the first set of cells 14.1 and, once the switch has been deactivated according to the duration required for the pulse, the second switch 16.2 is activated in order to operate the second set of cells 14.2. Through the present embodiment, the design of an electrolysis system is possible with multiple sets of electrolytic cells, supplying said cells by the activation and deactivation of multiple coordinated switches to distribute the direct current from one single energy source sequentially over the sets of cells. It is important to note that the design of said electrolysis plant depends on the optimum duration and characteristics of the current pulse, in particular in regard to the pulse duration and frequency factor, which are obtained according to the approach of the present invention.

[0093] As an example, if the electrolyzer 12 comprises a first set of electrolytic cells 14.1 formed by 50 cells connected in series, with each cell requiring a peak voltage of 2.5 v, a direct current source of 125v will be required to supply these 50 cells, distributing said 125 v in an equivalent form over each one of the 50 cells. This configuration can be supplemented with additional groups of electrolytic cells 14.2 connected in parallel to the first group, with each group having a switch in communication with the control unit for the pulsed distribution of direct current provided by the energy source. The number of groups of cells connected in parallel will be defined preferably according to the duration factor of the current pulse.

[0094] FIG. 3 shows a scheme of the electrodes of an electrolytic cell 20 formed by cylindrical electrodes 21, 22 according to the preferred embodiment of the present invention. Said electrodes are comprised by an arrangement of substantially concentric cylindrical electrodes, wherein there is a central hollow cylindrical electrode 21 and an outer electrode 22 of the cylindrical mantle surrounding the central cylindrical electrode 21. The central electrode 21 defines an inner space 23. In the central electrode 21 there is the oxidation reaction (generation of O.sub.2 in the case of water electrolysis). Over the inner side 22 of the outer electrode 22 the reduction reaction 22 occurs (generation of H.sub.2 in the case of water electrolysis). Both electrodes are separated each other by a space with an electrolyte provided in said space (in the case of hydrogen and oxygen generation, the electrolyte is based on water).

[0095] According to an embodiment, the central electrode 21 comprises openings in its surface allowing electrolytes entering the inner space 23 of the central electrode and the circulation of ions, and also allowing the oxidation reaction to occur both in the outer side 21 of the central electrode 21 and in the inner side 21 thereof. Additionally, and alternatively, the central electrode 21 can be surrounded by a separation mesh 24 with a physical barrier of separation provided that separate the oxidation zone (central electrode 21) from the reduction zone (outer electrode 22), thus facilitating the separation of gases generated in the electrolytic cell. Under this arrangement, the central electrode 21 comprises separation means (not shown) that keep distance between the separation mesh 24 and the outer side 21 of the central electrode 21, allowing the generation of the oxidation product over the surface of said outer side 21. Additionally, this distance allows the gas generated on the outer side 21 of the central electrode 21 to circulate to its extraction point, whether by going into the inner space 23 of the central electrode 21 through the openings or circulating over the outer side 21 of the electrode into the extraction point without being transferred to the generation zone of the reduction product.

[0096] In regard as openings, according to alternative embodiments, they may be formed by circular holes 25 and/or continuous grooves 25. The openings distribute along at least one part of the central electrode 21, preferably an upper part thereof, distributed in the extraction zones 27 provided to communicate the space between electrodes with the inner space of the central electrode 21.

[0097] The constructive aspects of the electrodes according to the preferred embodiment allow taking advantage of the capacitive and resonant characteristics of the electrolytic cell, preventing the saturation of the walls of the electrodes with the gases generated by maximizing the cell's resonant aspects, including the effect of overdamping and taking advantage of the diffusion and transfer of ions from one electrode to other in the standby cycle given by the intervals in the current supply of pulsing wave making use of the cell's capacitive aspects.

[0098] FIG. 4 shows a cross-section view of the lower part of an electrolytic cell 20 showing the preferred arrangement of the central electrode 21, the outer electrode 22, the separation mesh 24 and the inner space 23. Additionally, two extraction zones 25 are shown distributed over the extension of the central electrode 21 and the arrangement of the stopping devices 26 in said zones, formed in this case as O-rings. On the other hand, to the lower end of the electrolytic cell illustrated in FIG. 4, the cross-section of a feeding duct of electrolyte 30 is seen, where said duct is in communication with the central space 23 and/or the space between electrodes in order to feed the electrolyte to the electrolytic cell.

[0099] FIG. 5 shows a representative scheme of two electrolytic cells 20 and 20 according to FIG. 4 in cross section along the direction of the electrolyte feeding duct 30, with both cells being connected through the same electrolyte feeding duct 30. Under this embodiment, the electrolytic cells 20 and 20 can be electrically connected in series or in parallel, but the preferred connection is the electrical one in series by sharing the same electrolyte feeding and, thus, by operating simultaneously they decompose the electrolyte.

[0100] FIG. 6 shows a cross section view of an upper part of an electrolytic cell 20 showing the extraction points of the oxidation and reduction reaction products occurring therein. In fact, an extraction duct of the reduction product 21 is shown in communication with the outer electrode 22 for the recovery of the reduction product formed on the surface of said outer electrode 22. Additionally it is shown how the central electrode 21 extends through the extraction duct of the reduction product 31 up to an extraction duct of the oxidation product 32, wherein the inner space 23 of the central electrode 21 is communicated with said extraction duct of the oxidation product 32. According to this configuration, the extraction zones 25 with openings and stopping devices 26 favoring the circulation of the oxidation reaction product into the inner space 23 of the central electrode 21, along with the characteristics of the electrolysis process, wherein each products is formed over the subsides of different electrodes, allows facilitating the separation of both electrolysis products, with them being extracted in separate extraction ducts 31, 32 in order to have those products in later steps, for example for compression and storage.

[0101] FIG. 7 shows a scheme of an electrolysis system 10 comprising multiple electrolytic cells provided in communication with multiple feeding and extraction ducts. In particular, the embodiment represented in FIG. 7 shows five groups of electrolytic cells bound by the applicable feeding ducts of the electrolyte (30.1, 30.2, 30.3, 30.4 and 30.5) and the corresponding extraction ducts of the reduction reaction product (31.1, 31.2, 31.3, 31.4 and 31.5), and the corresponding extraction ducts of the oxidation reaction product (32.1, 32.2, 32.3, 32.4 and 32.5) under a similar scheme to that of FIGS. 5 and 6. Additionally, FIG. 7 shows the arrangement of a feeding tank 40 arranged to keep the electrolyte's operating level 41 inside the electrolytic cells, thus providing feeding to the feeding ducts of the electrolyte through a main feeding duct 30.0. The feeding tank 40 may comprise an electrolyte's feeding path 42 from the outside in order to compensate the decomposition of the electrolyte during the process. The arrangement of the electrolytic cells of FIG. 7 can be useful to take advantage of the present invention, comprising cells connected in series forming groups of cells, wherein said groups of cells are connected in parallel using switches and at least one control unit distributing a current signal in order to provide a rightly sized current pulse to each group of cell in a similar way to that stated in the scheme for FIG. 2b.

[0102] Finally, FIG. 8 shows a scheme of an electrolytic plant 50 comprising the system of the invention, generating arrangement of cells that can be operated under the same concept proposed in the present invention, using main feeding ducts 30.0, 30.0, main extraction ducts of the reaction products 31.0, 31.0, and main extraction ducts of the oxidation reaction products 32.0, 32.0. This scheme allows designing one or more feeding sources for the feeding of each arrangement of cells in order to cover the needs of current and voltage according to the statements of the invention and to provide a sequential production of each set of cells according to the requirements of current pulse frequency and duration according to the statements of the present invention. With this not only the electrolysis process' operating aspects in the electrolytic cells are optimized, but also the industrial aspects of an installation of this type of system in a compact electrolysis plant, for example for producing hydrogen and oxygen at industrial scale.

Working Example

[0103] In order to exemplify the implementation of the solution proposed by the present invention, the production of hydrogen and oxygen through water electrolysis is considered, using the system and methods of the present invention.

[0104] In the process of water alkaline electrolysis to generate H.sub.2 and O.sub.2, processes of oxidation and reduction take place as follows:

2H.sub.2O.fwdarw.O.sub.2+4H.sup.++4eoxidation (anode)

4H.sup.++4e.fwdarw.2H.sub.2Reduction (cathode)

2H.sub.2O.fwdarw.2H.sub.2+O.sub.2Overall reaction

[0105] The electrolysis of a mole of water produces one mole of hydrogen gas and half mole of oxygen gas in the normal diatomic forms thereof. A detailed analysis of the process shows the use of the thermodynamic potentials and the first law of thermodynamics. It is assumed that this process is carried out at 298 K and at one atmosphere of pressure, and that the relevant values are taken from the following table of thermodynamic properties (table 1):

TABLE-US-00001 TABLE 1 Amount H.sub.2O H 0.5O.sub.2 Change Enthalpy 285.83 kJ 0 0 H = 285.83 kJ Entropy 69.91 J/K 130.68 J/K 0.5 TS = 48.7 kJ 205.14 J/K

[0106] The process must provide energy for the dissociation plus the energy to expand the produced gases. Both are included in the enthalpy change of the above table. At a temperature of 298 K and one atmosphere of pressure the system operation is as follows:

W=PV=(101.3103 Pa)(1.5 mol)(22.410.sup.3 m.sup.3/mol)(298 K/273 K)=3715 J

[0107] As the enthalpy H=U+PV, the change of internal energy Y is therefore:

U=HPV=258.83 kJ3.72 kJ=282.1 kJ

[0108] This change in the internal energy must be accompanied by the expansion of the gases produced, so the change in enthalpy represents the energy necessary to carry out the electrolysis. Nevertheless, it is not necessary that the energy source inserts this energy in total, as electrical power, since the entropy increases in the dissociation process; the TS amount can be provided by the environment at temperature T. Then, the amount of energy to be supplied by the energy source is in fact the change in Gibbs' free energy, which is expressed as follows:

G=HTS=285.83 kJ48.7 kJ=237.1 kJ

[0109] As the result of the electrolysis process there is an increase of the entropy, the environment helps the process by providing a TS amount. The usefulness of Gibbs' free energy consists in indicating the amount of other energy forms that must be supplied in order to execute the process.

[0110] For practical purposes of calculating the mass obtained in an electrolysis process, and considering the unified Faraday's law and a distribution of constant current, the equation can be presented as:

[00013]$\mathrm{Obtained}.Math..Math.\mathrm{Mass}.Math.\left[\mathrm{gr}\right]=\frac{\left(\mathrm{Chemical}.Math..Math.\mathrm{Equivalent}.Math..Math.H_2\left[\frac{\mathrm{gr}}{\mathrm{mol}}\right]*I\left[\frac{\mathrm{Coulomb}}{s}\right]*t\left[s\right]\right)}{{\mathrm{Faraday}}^{}.Math.s.Math..Math.\mathrm{Constant}.Math.\left[\frac{\mathrm{Coulomb}}{\mathrm{mol}}\right]}$

[0111] For hydrogen, the electro-chemical equivalent is:

[00014]$\mathrm{Chemical}.Math..Math.\mathrm{Equivalent}.Math..Math.H_2=1,00794\left[\frac{\mathrm{gr}}{\mathrm{mol}}\right]$

[0112] Using the known values of the Chemical Equivalent of H.sub.2 and Faraday's Constant, and considering the generation of 1 g of H.sub.2 in one second, the following is obtained:

I=95724.9 A

[0113] With this information it is possible to calculate the optimum voltage matching the input energy of the cell with the output energy. In this case, once the current necessary has been obtained to produce one unit of mass of the reaction product using the chemical equivalent to said product for that purposes, it is possible to determine the electrical energy required at the cell entry for the time of 1 second, for the production of one gram H.sub.2 through the following equation:

Entry energy=.sub.t=0.sup.t=1[s](I*V.sub.optimal)dt

[0114] Then, and considering the output energy as the thermal product of the reaction, this case considering that the energy contained in 1 gram of H.sub.2 is 120011 J (Low Heat Value) and considering a 100% electrical efficiency, the following result is obtained:

V.sub.optimal=1.24[v]

[0115] Here it is important to note that the electrolysis process for the generation of hydrogen is widely known; thus, it is not an object of the present invention to restate the thermodynamics balances and equations associated with said process. Without prejudice to that and as shown by the present example of application, the optimum application to favor reactions in the production of hydrogen through electrolysis is about 1.24 volts, so that to obtain the maximum efficiency of energy transformation.

[0116] The optimum voltage can be also obtained by applying the standard potentials of reduction corresponding to the potentials measured in each electrode to favor the reduction and oxidation processes under standard conditions. Using the standard potentials of reduction, it can be defined that the oxidation reactions in the anode (2H.sub.2OO.sub.2+4H.sup.++4e) has a reduction potential of 1.229 V, while the reduction reaction in the cathode (4H.sup.++4e.fwdarw.2H.sub.2) has a potential of 0 V, with this valued being defined as the reduction potential in reference. Then, it is possible to calculate the potential of the cell (E.sub.cell) as follows:

E.sub.cell=E.sub.cathodeE.sub.anode

[0117] Wherein E.sub.cathode and E.sub.anode correspond to the potential standards of the cathode and anode for this reaction, respectively. Then, for the electrolytic cell in question the potential of the cell would be 1.229 V, this being the necessary potential to carry out the non-spontaneous reaction of hydrogen and oxygen production through water electrolysis.

[0118] With this optimum voltage of the electrolysis process and with the cell design consideration, operating parameters of the current power supply can be obtained such as pulse duration time, frequency and amplitude thereof, thus optimizing the application of current by minimizing the voltage required to operate the electrolytic cell in a resonant and capacitive fashion. In fact, by using this value and the above-defined equations the duration factor of the current pulse is:

[00015]$\sqrt{D}=\frac{1.24\left[v\right]}{V_{\max }}$

Then, and considering the design parameters, wherein the cell charge voltage in t=DT is V.sub.cell(DT)=2 [v] and the cell voltage in t=T is V.sub.cell(T)=1.8 [v], with those parameters being defined according to the constructive aspects of the cell, the frequency parameter (period) of the pulse wave is:

[00016]$f=\frac{1}{T}=\frac{1}{R*C*0.105}\left[\mathrm{Hz}\right]$

Therefore, the duration of the pulse wave is:

[00017]$D*T={\left(\frac{1,24}{\mathrm{Vmax}}\right)}^2*R*C*0,105\left[s\right]$

[0119] Then, the current flowing through the cell under these design parameters is configured as:

[00018]$\begin{array}{cc}{I}_{\mathrm{average}}=\frac{f}{\left(V_{\max }*\sqrt{D}\right)}.Math.\left(\frac{1}{2}.Math.{C\left(2.Math.\left(1-e^{-\frac{D/f}{\mathrm{RC}}}\right)+1,8\right)}^2-1,62.Math..Math.C\right)& \left[A\right]\end{array}$

[0120] Obtaining the current values for several values of V.sub.max.

[0121] Considering a power supply with V.sub.max=2.52 v is it possible to determine that the pulse duration factor is D0.24 for the optimum voltage desired. Then, considering the equation for the period and frequency and a high-capacitance electrolytic cell according to design parameters, as for example with a capacitance of 1.1 F and with a resistance resulting in a duty cycle of 0.18 ohm, it is possible to obtain that the pulse wave frequency supplying power to the system is about 50 Hz (a period of 0.02 seconds).

[0122] With this information it is possible to calculate the current circulating through the cell, which in this case is about 7.19 A. Then, using the ohm law it is possible to evidence that applying an optimum voltage to an electrolytic cell under the constructive parameters of a high-capacitance capacitor and under the operating parameters of the present invention in transient regimes, results in an apparent resistance of the system of 0.17 ohm, which is an advantageous situation compared with the standard electrolytic cells. In fact, below comparative values are presented between a standard cell operated in a standard way with direct current (table 2) and a cell according to the present invention and operated according to the solution stated (table 3), both of them under the same parameters of amplitude and current flow.

TABLE-US-00002 TABLE 2 Energy Effective Effective Consumption Effective Production H.sub.2 energy Efficiency consumed resistance voltage per kilo of H.sub.2 current [A] H.sub.2 [gr/hr] [Wh] [%] [Wh] [ohm] [V] [kWh/kg] 7.19 0.27 9.02 60.0% 15.0 0.2906 2.09 55.6

TABLE-US-00003 TABLE 3 Effective Effective Energy Consumption Effective voltage resistance H.sub.2 production H.sub.2 energy consumed per kilo of H.sub.2 current [A] [V] [ohm] [gr/hr] [Wh] [Wh] [kWh/kg] 7.19 1.27 0.177 0.27 9.02 9.1 33.3

[0123] In view of the above, it is possible to prove that for the same level of H.sub.2 productionconsidering the electrolysis system of the invention compared with a conventional systemreducing the energy consumption of the cell about 40% is possible, which translates into a substantial reduction of the disadvantages of implementing the alkaline electrolysis process at industrial scale. The big differences resulting between the implementation of a conventional solution and the solution of the present invention are given by the constructive considerations of the cell as capacitor, considering the capacitive and inductive aspects, along with the resistive ones in order to operate the cell under charge and discharge transient regimes. This approach results in current peaks over the electrolytic cell at the beginning of each charge period, which reflects in an apparent or reduce effective resistance, in this case about 0.17 ohm. Taking advantage of said current peak through supplying pulse wave and operation under transient regimes translates into increased efficiency, which exceeds the operation of a conventional cell and making the industrial solutions for the production of hydrogen and oxygen in an alkaline way competitive.

[0124] At this point it should be highlighted that the preceding example of application can be extrapolated to other electrolysis processes, being relevant to calculate the optimal voltage of this process and consider the transient regimes of the electrolytic cell both in charge as in discharge, where the capacitive, inductive and resonant aspects of said cell should be stressed.