Storage and reuse of hydrogen and oxygen generated by green energy in groundwater

Abstract

The storage device, earth hydrogen storage system, according to the invention is a system consisting of a plurality of underground wells drilled underground. Hydrogen is produced by electrolysis using green energy. Hydrogen and associated oxygen are stored in and recovered from cartridges (11, 8) mounted in said wells (5, 7), said cartridges being submerged by groundwater and at a suitable distance from each other. According to the system, circulating water of a closed loop is used for conveying gas generated in electrolysis in the form of bubbles. The gases are separated from the circulating water by volume expansion and form bubbles when they reach the respective cartridges (11, 8). With continuous operation, the bubbles would extrude more and more amounts of water from the groundwater in the cartridges (11, 8), pressurizing the system.

Description

Technical Field

[0001] The present invention is a hydrogen and / or oxygen storage system or storage device that uses groundwater as an energy storage facility. Background Art

[0002] Hydrogen is well known as an energy carrier and is currently stored in a variety of ways. This solution allows solar energy to be stored and converted back when solar energy is not available.

[0003] Storage plays a key role in the use of hydrogen as energy. Currently, the most common storage methods are to implement it as a gas, liquid or simple mixture.

[0004] By 2050, human energy demand is estimated to be three times that of the millennium, making the exploration of alternative energy sources (renewable energy) increasingly urgent and necessary.

[0005] One of the key issues to be addressed is a strong reduction in greenhouse CO2 emissions. Over the past two decades, there has been a great deal of interest in integrating hydrogen into the energy sector, which could be the basis for establishing a hydrogen-based energy economy.

[0006] The concept is to use hydrogen produced from different alternative energy sources (solar, geothermal, wind, biomass, etc.) in so-called fuel cells, where an electrochemical reaction converts the chemical energy stored in the hydrogen into electrical energy.

[0007] Since the hydrogen produced may be far away from the point of use both in space and time, it must be stored. Summary of the invention

[0008] The object of the present invention is to provide a low-cost solution for the intermittent storage of hydrogen energy which minimizes maintenance and repair costs, whether for a household or a large power plant.

[0009] Additional objects that may be understood or derived from the above and the remainder of the present disclosure have been solved by a device according to claim 1 , preferred embodiments of which are defined in claims 2 to 5 . BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 A preferred exemplary embodiment of the device according to the invention is schematically shown. DETAILED DESCRIPTION

[0011] The device according to the invention is particularly suitable for installation in areas where the soil can be drilled without significant costs using conventional drilling techniques and groundwater can be extracted.

[0012] For a practical embodiment of the invention, one or more wells 5, 7 are drilled using conventional techniques, each preferably having a diameter of 310 mm or more, and from an economic point of view, the depth of the well is preferably always the maximum depth that can be drilled in the earth. Figure 1 As shown, in each well 5, 7, below the water level of the groundwater 9, a container or cartridge 11, 8 closed at the top and sides but open at the bottom is installed in each well 5, 7. The cartridge is preferably fixed to the side of the well 5, 7 at a safe distance below the water level of the groundwater 9. The cartridge 11, 8 is maintained in a central position within the well 5, 7 by spacers.

[0013] A rated circulation pump 2 is installed in one of the wells 5 of the prepared well system. This circulation pump 2 will cause water from the well 5 to enter circulation from a safe depth relative to the water level in the well 5 through a suction pipe 10 and flow through a double-chamber electrolysis tank (tank) 1 - it forms an electrolyzer known to those skilled in the art, thereby forming two closed water systems 3 upstream of the tank 1 by branching the suction pipe 10 in two directions.

[0014] The water pipes 4, 6 returning from the electrolyser 1 to the wells 5, 7, respectively, are connected to the top connection points of the cylinders 11 and 8 arranged in the wells 5 (for hydrogen) and 7 (for oxygen), respectively. At the top of each of the cylinders 11, 8 for hydrogen and oxygen, respectively, at the connection point of the respective return pipe 4, 6, the cross section of the pipe is increased, which allows the gas to be trapped (accumulated) below the water level.

[0015] The two closed water systems 3 will be formed when the circulation pump 2 is started and draws water from the well 5, these two water systems return the water that has been at least partially electrolyzed by the electrolysis tank 1 to the cylinders 11, 8 in the wells 5, 7. This circulation is continuous.

[0016] The activation and energy recovery of the system are controlled by appropriate electronics.

[0017] When green energy, preferably green energy generated by solar panels, wind turbines, etc., is available, a direct current (DC) current provided by the green energy is supplied to the negative and positive electrodes of the electrolysis tank 1. In the electrolysis tank 1, hydrogen and oxygen are produced by the DC current through a known water electrolysis process under continuous water circulation. Since the electrodes arranged in the electrolysis tank 1 are perforated stainless steel plates, the gas in the form of bubbles formed is carried away by the water flow from the corresponding (i.e., positive or negative) side of the tank 1 through the return pipe 4, 6 to the corresponding cylinder 11, 8, where the gas is separated from the water.

[0018] In the cylinders 11, 8, the increased cross section causes hydrogen and oxygen to accumulate, respectively, so the gas begins to displace the groundwater from the hydrogen / oxygen cylinders. Since the water flow is continuous, the gas cannot resist the water and accumulates continuously in the cylinders 11, 8. As the amount of gas accumulation increases, the groundwater 9 flows continuously from the cylinders 11, 8 to the bottom of the wells 5, 7.

[0019] When the cartridge 11, 8 is completely filled with gas, the system switches to the next cartridge in the next well using a suitable intervening valve system known to those skilled in the art.

[0020] The gas (ie hydrogen or oxygen) accumulated in the cylinders 11, 8 of the wells 5, 7 is compressed by the pressure of the groundwater 9 corresponding to the depth of the wells, so that it can be easily recovered and thus subsequently used.

[0021] The storage device according to the invention requires very little maintenance since the system has very few moving parts and the pressure is maintained by the soil structure.

[0022] The present invention primarily uses fuel cells to convert recovered hydrogen into electricity, but it can also be used to power hydrogen turbines, or to use the recovered hydrogen and oxygen in other ways. It is also clear to those skilled in the art that the storage device according to the present invention is also suitable for the storage and subsequent use of gases other than hydrogen and oxygen that do not react with water.

[0023] Summarize

[0024] The invention provides a solution for temporary storage of hydrogen and oxygen, for example generated from green energy, at a significantly lower cost than existing solutions. The device consists of a single circulating water pump and is therefore much cheaper to construct and operate than conventional gas storage solutions.

[0025] As the depth of the well increases, the pressure of the stored gas can be adjusted due to the increase in hydrostatic pressure. Recovery is therefore simple and does not incur additional costs.

[0026] When filling the well with gas, only the energy consumption of the circulation pump has to be considered, so it is much cheaper than other systems with tanks.

[0027] The pressure holding capacity of the tank is not lost over time due to the surrounding ground pressure and the hydrostatic pressure, and since the air cartridges are not subjected to extreme pressure changes, they have a long life.

[0028] With the solution according to the invention, large quantities of gas can be stored in the area of ​​a suitable soil structure and recovered within a suitable period of time when required.

[0029] Reference numerals list

[0030] 1 (electrolysis) tank

[0031] 2 Circulation pump

[0032] 3 (Closed) Water System

[0033] 4 pipes (for return water mixed with hydrogen)

[0034] 5 Wells

[0035] 6 pipes (for return water mixed with oxygen)

[0036] 7 Wells

[0037] 8 (with oxygen inside) cylinder

[0038] 9. Groundwater

[0039] 10 (Circulation pump) suction tube

[0040] 11 (with hydrogen inside) cylinder.

Claims

1. A storage device for underground storage of gases, in particular hydrogen and / or oxygen, characterized in that The gas is filled into a container (11, 8) against the pressure of groundwater (9) in a well (5, 7), wherein the container (11, 8) is arranged in the well (5, 7) and is open at the bottom.

2. The storage device according to claim 1, characterized in that The gas is oxygen and / or hydrogen obtained by electrolysis of water, is filled into the container (11, 8) together with water in the form of bubbles formed in water, and is separated into a gas phase and a liquid phase in the underground container (11, 8).

3. The storage device according to any one of claims 1 to 2, characterized in that The wells (5, 7) are drilled or dug wells.

4. The storage device according to any one of claims 1 to 2, characterized in that: The well is located in open water.

5. The storage device according to claim 1, characterized in that: The gas is a gas other than hydrogen and oxygen that does not react with water.

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