REACTOR THAT PRODUCES HYDROGEN BY REDUCTION OF HYDRONIUM IONS PRESENT IN THE CHEMICAL EQUILIBRIUM IN WATER AND BY OXIDATION OF THE ORGANIC MOLECULES FOUND IN EXCREMENT

Abstract

An electrochemical reactor designed to increase the efficiency of hydrogen production from faeces and urine (excrement) is disclosed. Said reactor comprises two half-cells separated in a selective manner, a membrane systems separating the half-cells (comprising a proton-exchange and an anion-exchange membranes) and a system of electrical bridges that allow two mutually perpendicular electrical fields to be formed, with the electrical field in the horizontal direction between the two half-cells being greater than the vertical electrical field generated within the anode. The half-cells have a configuration of two resistances in series, which allows the potential of each compartment to be controlled in an independent and complementary manner by adjusting the conductivity of the solutions in the half-cells. Said configuration allows the consumption of energy to form hydrogen to be significantly reduced in comparison with conventional electrolytic cells using water in an alkaline medium by combining the chemical processes of electrolysis (anode) and the law of chemical equilibrium (cathode).

Claims

1-10. (canceled)

11. A hydrogen generation reactor, comprising: a cathode comprising a bridge located at a bottom section of a half-cell connected to an anodic bridge by a screw through an L-shaped leg, and where the screw must be outside the fluid system; an anode; and a system of electrical bridges designed to form a horizontal electrical field that is perpendicular to a vertical electrical field, wherein the horizontal electrical field is greater than the vertical electrical field generated within the anode, with a 4:1 ratio of the vertical electrical field to the horizontal electrical field.

12. The reactor of claim 1, wherein the screw is a stainless steel screw.

13. A method for producing hydrogen, comprising: oxidizing homogenized feces until generating hydronium ions in an anode of a reactor, which hydronium ions are attracted by an electrical bridge, and in turn by the bridge and cathodic plates, in order to transfer the hydronium ions along with water molecules through a proton exchange membrane; reducing hydronium ions on the cathodic plates, forming gaseous hydrogen (H.sub.2); and transporting hydroxyl ions from the cathode to the anode through a generic membrane that is part of a membrane system.

Description

DESCRIPTION OF THE FIGURES

[0031] FIG. 1 is a complete diagram of the reactor, which includes: (1.1) The two half-cells (anodic half-cell on the left, cathodic half-cell on the right) and, (1.2) the membrane systems;

[0032] FIG. 2 is a diagram of the anodic half-cell in particular, showing the arrangement of the different anodic plates that are part of the system configuration;

[0033] FIG. 3 is a diagram of the cathodic half-cell in particular, showing the arrangement of the different cathodic plates that are part of the system configuration;

[0034] FIG. 4 is a general representation of the electrical fields that affect the system, one with horizontal orientation (E1) and other one with vertical orientation (E2).

[0035] FIG. 5 shows the movements of the negative and positive charges through the membrane systems, according to the electrical fields.

DETAILED DESCRIPTION OF THE INVENTION

[0036] In addition to previously stated, the object of the present application can be appreciated in detail by the subsequent description of the reactor developed:

[0037] In accordance with FIG. 1, the reactor disclosed herein consists of an electrolytic cell that has the anode and cathode separated and materially connected in a selective manner so that some of the species formed in the oxidation process at the anode (hydronium ions) they can be transferred through a membrane systems (1.2) and react in the cathode, while hydroxyl ions formed in the cathode as a result of chemical equilibrium of water, are transported by migration to the anode and thus establish a balance of matter and charge.

[0038] Specifically, and according to FIG. 2, the anode is formed by 32 metal plates (2.1) located in the center of the half-cell, which come into contact with the surface that contains the membrane systems (1.2) to decrease the distance to the cathode plates. Said configuration allows the negative charge density to be given towards the upper region of the half-cell, and that the positive charges are centered towards the lower zone.

[0039] In a particular embodiment of the invention, the main metal plates (2.1) in the anode are 8, which can be manufactured in 316 L stainless steel and can have a rectangular shape of 6 cm12 cm.

[0040] In another particular embodiment of the invention, the separation distance between the auxiliary plates and the anodic bridge (2.2) is 0.5 cm.

[0041] For its part and as seen in FIG. 3, the cathode is composed by a metal bridge (3.3) located at the bottom of the half-cell, which is connected to the anodic bridge (2.2) by a stainless steel screw through of an L-shaped leg, and where the screw must be outside the fluid system.

[0042] In the reactor disclosed here, the cathode plates are divided into two groups: two auxiliary plates (3.2) that are located on the faces of the half-cell and 30 main plates (3.1) that are centered on the body of the half-cell. This configuration allows, for example, hydronium ions to pass from the anode to the cathode by migration and move from the bottom of the cathode to the top of the cathode, and from the cathode input to the bottom of the cathode.

[0043] Now, in accordance with FIG. 4, the system of electric bridges (2.2, 3.3) that are part of the reactor disclosed here are designed to form two electrical fields (E1-E2) perpendicular to each other, the electrical field being directional horizontal between the two half-cells greater than the perpendicular electric field generated within the anode, with a ratio (4:1).

[0044] Additionally, it is pertinent to point out that, from the electrical point of view, the two half-cells (1.1) that make up the revealed reactor have a configuration of two resistors in series, with which it is possible to control the potential of each compartment independently and complementary to through the adjustment of the conductivity of the solutions in each of the half-cells.

[0045] In a particular embodiment of the invention, the appropriate potential values anode: cathode are 1V: 2.5V.

[0046] However, the reactor disclosed here is designed to produce hydrogen from electrolysis oxidation reactions of the organic molecules present in the faeces, which are given separately to the reduction reaction of the hydronium ions present and formed in the chemical equilibrium of water. For this purpose, in both compartments (cathodic and anodic) stainless steel plates are arranged that act as electrodes (2.1 and 3.1) and electric bridges (2.2 and 3.3).

[0047] The reactor conditions imply that homogenized faeces are in the anode, while in the cathode there is water and small amounts of a conductive electrolyte. For its part, the membrane systems (1.2) that separates the two half-cells (1.1) is composed of a proton exchange membrane of nafion combined with a generic membrane (stretch film, polymeric elastic membrane of linear, low density polyethylene with an approximate pore size of 30 A) or anion exchange.

[0048] In a particular embodiment of the invention, the conductive electrolyte present in the cathode is phosphoric acid (H.sub.3PO.sub.4).

[0049] When using the urea present in the urine as a model organic molecule, its oxidation generates in the anode hydronium ions (see semi-reaction 1a), which, once formed, are attracted by the electric bridge located at the bottom of the anode (electric field E.sup.2) and in turn are attracted to the bridge and cathode plates E.sup.1 (FIGS. 4 and 5), causing the transfer of hydronium ions and water molecules through the nafion membrane. This transfer means that an experimental balance of load and matter is established in the system.

Anode: CO(NH.sub.2).sub.2(aq)+7H.sub.2O.fwdarw.N.sub.2(g)+6H.sub.3Q.sup.++CO.sub.2+6e.sup.(1a)

Cathode: 6H.sub.3Q.sup.++6e.sup..fwdarw.3H.sub.2(g)+6H.sub.2O (1b)

Total reaction: CO(NH.sub.2).sub.2(aq)+H.sub.2O.fwdarw.N.sub.2(g)+3H.sub.2(g)+CO.sub.2(g) (1)

[0050] Already in the cathode, the hydronium ions are reduced on the cathodic plates (semi-reaction 1b) forming gaseous hydrogen (H.sub.2), after which, and by the Le-Chtelier's principle, the chemical equilibrium shifts to the right side producing hydroxyl ions and compensating for the loss of hydronium ions.

[0051] Finally, part of the hydroxyl ions is transported by migration from the cathode to the anode through the generic membrane that is part of the membrane systems, facilitating the kinetics of the urea oxidation reaction in basic medium.

[0052] The reactor disclosed here allows to significantly reduce the energy consumption required to produce hydrogen from the oxidation process of the organic matter present in the faeces. In this way, the application of this technology allows to oxidize the organic matter present in the faeces, generating sludge and few amounts of gases (nitrogen and carbon dioxide), but allowing the use of energy to form gaseous hydrogen.

[0053] This process has different advantages, which include:

[0054] 1. Reduce water pollution by harnessing the energy contained in faeces;

[0055] 2. Reduce the pollution caused to the atmosphere by the gases of harmful effects produced by the combustion of the explosion engines that use hydrocarbons, promoting the use of hydrogen technology as fuel without changing the technology of the current explosion engines; and,

[0056] 3. Reduce the cost to produce hydrogen since the raw material is faece and the energy applied is less than to other technologies.

[0057] The disclosed reactor uses electrical energy to carry out two chemical processes separately, so that the oxidation and reduction processes are carried out in a compartment separately selectively but not electrically isolated, while to compensate the current of the system, an electric bridge is used in stainless steel capable of increasing the production of hydrogen in the cathode.

[0058] The system of electrical bridges (2.2 and 3.3) that are part of the reactor disclosed here, may eventually be suspended because the membrane systems (1.2) is able to function at the same time as an electrical bridge, the above, although a decrease in the applied current (energy applied to a certain potential) as a result of an increase in the resistance of the system, with the consequent decrease in the amount of hydrogen generated (energy produced in the form of hydrogen).

[0059] However, when the system is connected to an external source, the central plates of the anode (2.1) are positively charged and the bridge of the lower part is negatively charged. On the other hand, the anode bridge (2.2) is connected to the cathode bridge (3.3), and although said plate is slightly negatively charged, the central plates of the cathode (3.1) are loaded more strongly since they are directly connected to the source and for this reason the hydronium ions move in the manner described in FIG. 5.

[0060] It should be noted that for an electric current to present, charges must flow in both directions, which is why once the system consumes hydroniums in the cathode by chemical equilibrium it generates hydroxyl ions (increasing its density in said compartment), which by migration are transported to the anode where the auxiliary plates have been arranged in their lateral areas to improve the internal dynamics of the system since it increases the density of negative charges at these sites, while in the center and in the lower area there is a higher density of protons, thus facilitating the protonic flow.

[0061] The reactor disclosed here takes advantage of the energy contained in the oxidizable molecules of the faeces, and although external energy is still required to transport the charges across the membranes, the potential that must be applied to electrolyze the water molecules is 1.23 V, while to electrolyte urea molecules is 0.37 V. On the other hand, the chemical equilibrium reaction in the cathode is spontaneous (that is, requires 0.00 V), thus obtaining higher electrical efficiencies to 100%.

[0062] Example

[0063] In order to show the operation and advantages of the reactor according to the present invention, a comparative example between a conventional cell and said novel reactor is presented below.

[0064] In this sense, while in conventional cells that use water the oxidation and reduction reactions are carried out in the same compartment (that's the reason why they normally generate a maximum of 66% H.sub.2 and 34% O.sub.2), when used the system disclosed in the present invention obtains percentages of hydrogen greater than 90%.

[0065] On the other hand, the energy consumption in the form of electric current is much higher when conventional systems are used because the potential that is required to electrolyze the water molecule is 3.32 times greater than to electrolyze an organic molecule such as urea. Now, although conventional cells can be used to electrolyte urine, the reactions are carried out in a single compartment presenting undesirable reactions such as foaming and nitrogen oxides formation, which decreases the percentage of hydrogen and increases energy consumption.

[0066] Contrary to the above, the processes presented in the reactor disclosed here allow to reduce energy consumption to form hydrogen in a significant way compared to conventional cells that use water in alkaline medium. Specifically, the initial calculations indicate that the energy consumption of the reactor of the present invention corresponds to 25% of the energy consumption of conventional cells, a decrease that is due to the fact that organic molecules such as urea have a low oxidation potential and that the cathodic reaction uses the chemical equilibrium of water, so that once hydrogen is formed and thanks to the Le Chtelier's principle, hydroxyl ions spontaneously form which compensate for the hydronium ions consumed.

[0067] Thus, using the reactor disclosed here, it has been possible to obtain up to 92% pure hydrogen with flows up to 40 L/h by applying an electrical energy equivalent to 14 V and 2 A of electric current.