Compact hydrogen alkaline electrolyser

Abstract

The present invention relates to a high-efficiency hydrogen electrolyser consisting of a single casing containing four inner cavities having identical cubic capacity which are intercommunicated at the top to share a common gas outlet and which may also be intercommunicated at mid-height to share filler material. At the bottom of each cavity there is a solid bar longitudinally arranged such that the upper bar serves as a cathode and the lower bar serves as an anode, resulting in the optimisation of the electrolysis system by adding acidified water and providing DC power supply.

Description

[0001] DESCRIPTION

[0002] Compact hydrogen alkaline electrolyzer.

[0003] OBJECT OF THE INVENTION

[0004] Alkaline water electrolysis in an acidic medium is the decomposition of water (H2O) into oxygen (O2) and hydrogen (H2) gases by means of an electric current through acidified water. There are a large number of alkaline electrolysers, hydrogen generators, most of them being very similar or identical in design. When the objective of the equipment is to generate hydrogen, a filter must be placed at the outlet to separate both gases. These equipment have a water consumption derived from the dissociation into hydrogen and oxygen that is released in gas mode, however, the need for refilling is mainly motivated because when the short circuit occurs between the anode and the cathode, a certain amount of energy is released in the form of heat, also releasing water vapor.In addition to water losses, the increased temperature in certain hazardous applications causes the system to become physically unstable, requiring temperature control and requiring permanent cooling. This also increases the equipment's power consumption (amperes).

[0005] In most systems, the alkaline electrolyzer is configured by grouping several anode and cathode plates, introducing a cooling system, and incorporating a more or less continuous supply of acidified water. Ultimately, the instability of the non-membrane-exchange alkaline electrolysis of acidified water is assumed to be inevitable.

[0006] The improvement in the devices and object of the present invention consists of a specific configuration that prevents overheating and thus avoids the need for refilling by evaporation and also reduces the need to increase the supply amperage to a negligible point, making the system stable and intrinsically safe. Correct stacking of several identical alkaline electrolyzers with this configuration is simple, safe and especially limited in price, and a particular configuration of this stacking in a single container is also part of the present invention. BACKGROUND OF THE INVENTION

[0007] Various systems are currently known that carry out similar processes, with the following being of special interest:

[0008] 1 e) WO2018046781 . The object of this invention is a 2MW hydrogen generator housed in a container that seeks to solve the difficulty of being able to house the necessary elements to be able to produce up to 400Nm 3 / h in a container. The equipment is grouped together to cover the needs of the two 1 MW stacks with a single unit of each. An oxygen separator, a hydrogen separator, a heat exchanger, air heaters, a chiller, deionization resins, water pumps, and a hydrogen purification system are required.

[0009] 2 e ) WO2018189409. System for monitoring and controlling an electrolysis stack and procedures for minimizing stack degradation and maximizing hydrogen production with said system.

[0010] 3 e ) WO2018189410. Electrical connection for an electrolyser stack, suitable for explosive atmospheres.

[0011] 4 e) WO2018202926. Operating procedure for an electrolyzer plant powered by renewable energy.

[0012] 5 e ) ES2477542. High-temperature electrolyzer (HTE) with stacking of electrolysis cells with improved operational safety and high efficiency. To this end, according to a first embodiment, the invention relates to a module for high-temperature electrolysis.

[0013] 6 e ) ES2687973. Refers to an oxyhydrogen generator and a process for producing oxyhydrogen gas used to increase the efficiency of internal combustion engines and, in particular, engines that use gasoline, diesel and natural gas, as well as fixed combustion installations. 7 s) ES2080238. Electrolyzer comprising at least two elementary electrolysis cells, electrically connected in series along a common vertical wall. Series type electrolyzers, comprising a succession of elementary electrolysis cells electrically connected in series, in which two successive elementary cells comprise a common metallic vertical wall that ensures the electrical connection between the cells, adding the interposition between the titanium plate and the iron, steel or nickel plate, a sheet of a barrier material that has the property of opposing an emigration of atomic hydrogen to the titanium plate

[0014] 8 e) ES2824901. It basically uses AEM technology, i.e. alkaline with solid polymer electrolyte (membrane), which makes it possible to reduce production costs thanks to the use of catalysts with a non-noble metal base in both the anode and the cathode and an alkaline membrane normally available on the market or, advantageously, an alkaline membrane with certain characteristics.

[0015] 9 e ) ES2898673. This consists of a method for generating hydrogen gas for use in motor vehicles to increase the performance and reduce emissions of the vehicle's internal combustion engine, and a method for controlling the safe generation and use of hydrogen gas. A hydrogen generation and control system and a method for controlling the safe generation and use of hydrogen gas in motor vehicles are provided, respectively.

[0016] 10 e) ES-2903384. Improved electrolysis equipment that includes, among other elements, an electrolyzer that includes an anode chamber that houses an anode, a cathode chamber that houses a cathode and a diaphragm that divides the anode chamber and the cathode chamber; an electrolyte discharge line on the cathode side connected to the cathode chamber to discharge an electrolyte on the cathode side that contains hydrogen gas from the cathode chamber; a gas-liquid separation means on the cathode side connected to the electrolyte discharge line on the cathode side to separate the hydrogen gas from the electrolyte on the cathode side. 1 1 e ) ES2837255. Electrochemical equilibrium cells that can adjust the pH in two electrolyte solutions simultaneously.

[0017] 12 e) W02007085091 . It consists of a hydrogen generating apparatus comprising: a housing, an electrolysis cell within the housing, each of the electrolysis cells including a container and a plurality of electrodes in the container capable of generating hydrogen from an electrolyte when an electric current is passed therethrough; A component connector acting between a first member of the hydrogen generating apparatus and a second member at least associated with the hydrogen generating apparatus, The component connector includes a structural fixing element for fixing the first element to the second member and a damping element in association with the structural fixing element for damping vibrations of the first member to the second.

[0018] 13 e) WO2007133174. It consists of a system for generating hydrogen and oxygen by water electrolysis to supplement a hydrocarbon fuel burned in a combustion chamber, which comprises, among others, a cooling system.

[0019] 14 e ) US2008047830. It consists of an electrode for use in a hydrolysis cell comprising a series of electrically conductive, perforated, non-vertically oriented wafers spaced apart in a congruent stack, and a connector for connecting each wafer in said series to an electrical circuit.

[0020] The proposed invention contains the following advantages and, therefore, novelty, with respect to the known state of the art, while there are no references to a system that meets all these characteristics that the proposed invention brings together:

[0021] Thermal stabilization of the alkaline electrolysis process, eliminating the need to add cooling elements, which represents significant savings in the installations required for a scaled system.

[0022] Electrical stabilization of the electrolysis process, eliminating power consumption variability. Facilitates serial or parallel connection of various equipment, making grouping by stacking basic cells, considered as a standard system, more cost-effective.

[0023] In both the unit cell and the outer casing, the hydrogen generation system itself serves as a tank for the alkaline solution, which is the raw material for the production system, resulting in considerable space savings.

[0024] DESCRIPTION OF THE INVENTION

[0025] The proposed invention, "Compact hydrogen alkaline electrolyzer," is based on a sealed box made of plastic material containing four interior cavities of equal volume. The four cavities are generated by positioning three interior walls that create these separations, such that they do not cover the entire height completely but rather have upper slots, allowing the generated gases to escape to the outside through a common upper chamber. At the bottom of each of these interior cavities is a pair of solid bars made of an electrically transmissive metal, with a circular section. These bars are positioned parallel to the bottom and axially coincident with the vertical plane equidistant from each of the two lateral walls of each cavity, separated by a minimum distance between them, with the lowest of them being equally close to the bottom.Each of these bars has a sealed exit to the outside at one end, one from the front and the other from the back, and in both cases a fit is made at each end at both ends that prevents not only displacements and deformations due to buckling but also vibrational movements, and the distribution of exits to the outside of the bars is done in a staggered manner, so that if in the right cavity it is the upper bar that exits from the front, in the central cavity it is the lower bar that protrudes frontally, and in turn it is the upper one that protrudes from the front in the left cavity.Next, an electrical interconnection between bars is made first, and finally the electrical connection to the external DC power supply is made so that the cathode (connection to the negative pole) is in the upper position. The interconnection between bars is carried out in such a way that it is always the lower bar that is connected to the positive pole, and therefore functions as the anode. Finally, it is noted that it is necessary to fill each of the four interior cavities with an alkaline solution to a specific volume, found between a maximum and a minimum, and that they can be interconnected so that the alkaline solution filling is unique. It is recommended that the minimum level coincide with the communication holes for leveling due to the effect of communicating vessels. The size and height of the holes for communicating vessels are such that the isolated electrolytic effect of each of the four interior cavities is possible.

[0026] The geometric configuration, the distances between components, and their sizing are crucial to ensuring the balance that optimizes the electrolysis process, all of which is dependent on maintaining a specific concentration of the alkaline solution.

[0027] The device object of the invention is designed to allow the connection of a plural number of units, all arranged in an orderly manner, while maintaining the singular operation. Thus, two or more electrolyzers are arranged in a single container, sharing the oxyhydrogen gas outlet, thereby increasing the hydrogen flow rate obtained without sacrificing the performance optimization obtained by the singular cell, which is the primary, but not the only, essence of the present invention.

[0028] BRIEF DESCRIPTION OF THE DRAWINGS

[0029] To complement the description being made and in order to help better understand the characteristics of the invention, in accordance with a preferred example of practical embodiment thereof, a set of figures is attached as an integral part of this description, in which, for illustrative and non-limiting purposes, the following has been represented:

[0030] Figure 1 .- Shows an isometric view of the assembly.

[0031] Figure 2.- Shows a section of the cistern, with interior chambers.

[0032] Figure 3.- Shows a detail of the front electrical connections.

[0033] Figure 4.- Shows a detail of the rear electrical connections.

[0034] In the aforementioned figures the following constituent elements can be highlighted: 01.- Exterior drawer.

[0035] 02.- Interior wall.

[0036] 03.- Anode.

[0037] 04.- Cathode.

[0038] 05.- Single gas outlet.

[0039] 06.- Single filling.

[0040] 07.- Drill for alkaline solution intercommunication.

[0041] 08.- External connection to positive pole

[0042] 09.- External connection to negative pole

[0043] DESCRIPTION OF A PREFERRED EMBODIMENT

[0044] For the purposes of this preferred embodiment, and in relation to the configuration that includes all electrolysis systems, the construction of the equipment for generating hydrogen gas and oxygen gas from alkaline solution will include the elements described below.

[0045] 1 . Outer drawer (01), with interior dimensions (width x length x height) 480 x 200 x 290 [mm] subdivided into four interior chambers across its entire width by means of three identical interior wall units (02), separated from each other and from the interior side of each of the two outer drawers by a distance equal to 50mm (after deducting wall thicknesses). This allows the volume of each cavity, for functional purposes, to be between a minimum of 5 litres and a maximum of 7 litres.

[0046] 2. At the bottom of each of the four cavities, there are perforations on the front and rear faces, two on each side. The lower front and upper rear will be through holes and the upper front and lower rear will be blind, both with a nominal diameter equal to that of some metal bars transmitting electricity. The position of all the holes is centered with respect to each side wall, their centers on the same vertical line, with the distance between the centers of the lower hole and the floor being between 15 and 20 mm and the distance between the centers of the holes on the same vertical line being between 12 and 15 mm, always respecting that the axes of the bars that pass through or are inserted into these holes are arranged with their axes parallel to the back wall.These bars will be about 5 cm longer than the total interior length of the outer drawer (01), and will have a threaded tip with a length of 4 cm, so that when inserted through the through side leaving the non-threaded end inserted into the non-through hole, sealing to prevent leaks on both sides, a system is obtained consisting of metal bars that transmit electricity, at the bottom of each interior cavity, each protruding with a threaded tip at one end. When electrically connecting the final system, it will be done in such a way that the positive pole is always at the bottom and consequently the negative pole is reserved for the upper line, and being in an electrolysis system this means that the lower bar will act as the anode (03) and the upper bar as the cathode (04).

[0047] 3. Two threaded holes will be made in the roof of the outer box (01), one for a single filling (06) of alkaline solution and the other for a single outlet of gases (05) H2 and O2 as a result of electrolysis.

[0048] 4. In each interior wall there will be a through hole, about 8mm in diameter, and an upper opening. The through hole will be located at a height of approximately 250mm from the bottom and during assembly it will be distributed in such a way that one of them is on the front side and the other two on the back side, these holes acting as communicating vessels between chambers, marking the minimum level of acidified water, and therefore being the intercommunicating holes of alkaline solution (07) that makes possible the existence of a single filling (06). The upper openings also allow a single gas outlet (05).

[0049] 5. The threaded tips of the anode (03) and cathode (04) bars of the outer drawer (01) will be interconnected with each other from one to the next on each side - front and rear. The final system is connected in such a way that the positive pole always connects to the upper bars, which will therefore be the cathodes, and the negative pole connects to the lower ones which will therefore be the anodes, the electrolysis working in isolation chamber by chamber. The power supply of the electrolyser assembly that corresponds to this description of a preferred construction is 12 v VDC, with each of the four cavities, naturally as a consequence of the series interconnection, having an effective potential difference of 3V, resulting in the set of all the aforementioned characteristics resulting in the ammeter consumption remaining stable naturally, without additional peripheral equipment to the specific electrolysis.Additionally, by arranging a plural number of these compact alkaline electrolysers in such a way that all are integrated in a single container, nested and interconnected to a single collector all the particular gas outlets (05,), a rack of electrolysis cells is achieved with a high flow rate of generation of oxyhydrogen gas and an optimal performance by respecting the singular operation of each of its component elements that make up the aforementioned nest.

[0050] It is not considered necessary to expand this description further so that any person skilled in the art can understand the scope of the invention and the advantages derived from it. The materials used, dimensions, and joining procedures themselves are subject to variation as long as this does not imply a change in the essence of the invention.

Claims

CLAIMS 1.- Compact hydrogen alkaline electrolyzer, characterized by being configured from a rectangular prism-shaped box with four interior cavities equal, since, due to the distance and electrical insulation between them, the electrolysis process that occurs in each cavity is independent of one another, since at the bottom of each of these cavities, a pair of bars are located equidistant from both walls, separated from each other at a minimum distance and occupying the entire length of the cavity, the lower one being used as the anode and the upper one as the cathode, and the bars of the four cavities being interconnected in series on the outside so that the arrangement of the anode at the bottom and the cathode immediately above is maintained. 2.- Compact hydrogen alkaline electrolyzer, according to claim 1, characterized by having perforations in the interior walls. 3.- Compact hydrogen alkaline electrolyzer, characterized in that it comprises two or more compact hydrogen alkaline electrolyzers, according to claim 1, which are arranged within a single container sharing oxy-hydrogen gas outlet.

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