AT525358B1 - PROCESS FOR THE ELECTROLYTIC PREPARATION OF AN OXYGEN-CONTAINING AND HYDROGEN-CONTAINING GAS MIXTURE - Google Patents

Abstract

The invention relates to a method for the electrolytic preparation of an oxygen-containing and hydrogen-containing gas mixture, in which current is introduced into a liquid electrolysis medium (3) via electrodes (11, 12) and oxygen gas and hydrogen gas are thus generated, which from the electrolysis medium (3) are at least partially mixed form exits as electrolysis gas, characterized in that immediately after exiting the electrolysis gas is mixed with an additional gas, which comprises lower hydrocarbons, to form a gas mixture.

Description

Description

The invention relates to a method for the electrolytic preparation of an oxygen-containing and hydrogen-containing gas mixture, in which current is introduced into a liquid electrolysis medium via electrodes and oxygen gas and hydrogen gas are thus generated, which exit the electrolysis medium in at least partially mixed form as electrolysis gas.

It also relates to an electrolysis device for the electrolytic production of an oxygen-containing and hydrogen-containing gas mixture, the electrolysis device having at least one container for receiving electrolysis medium and having electrodes arranged therein for introducing current into the electrolysis medium.

In water electrolysis, water is converted from a liquid electrolysis medium into hydrogen gas and oxygen gas by introducing electricity. These gases rise from the electrodes as they form. Mixing hydrogen and oxygen produces oxyhydrogen, also known as HHO or Brownian gas, later called electrolysis gas. This gas can be used well as a fuel, but it is highly explosive and flammable and therefore poses a safety hazard. Therefore, the hydrogen gas and oxygen gas are often separated immediately after generation to avoid mixing. However, more complex structures are necessary for this and it may not be possible to completely prevent partial mixing.

In DE 3913143 A1 a welding device is described which can be operated with a mixture of HHO gas and hydrocarbon gas. This gas mixture is produced in a manner that is not described in detail.

In JP S63304093 A a container is disclosed in which a liquid containing hydrocarbons is stored. HHO gas is introduced into the container via a pipe 2 and passed through the liquid, whereby the gas is enriched. However, the HHO gas is highly flammable and explosive before mixing.

US 2009/134041 A1 discloses an electrolysis device that provides HHO gas. It is provided that this HHO gas is discharged from the electrolysis device after it has been produced and fed into the cylinders of an internal combustion engine, with mixing with additional gas being able to take place in a carburetor. Here, too, there is a risk of explosion when conducting the pure HHO gas.

The object of the invention is accordingly to increase the safety of the electrolysis or the electrolysis device and still provide a gas mixture that can be used well.

[0008] This object is achieved in that the electrolysis gas is mixed with an additional gas, which comprises lower hydrocarbons, to form a gas mixture immediately after it has exited.

It is also achieved in that at least one inlet of the container is connected to an additional gas source for supplying the container with an additional gas comprising lower hydrocarbons.

The immediate mixing of the electrolysis gas with the additional gas ensures that the proportion of oxygen in the gas mixture is reduced. This greatly reduces the risk of explosion and makes it easy to handle the gas. The hydrocarbons ensure that the resulting gas mixture is still combustible and can be used as a fuel.

[0011] Under immediately after the exit is meant that the mixing with the additional gas takes place in the region of the liquid surface of the electrolysis medium, ie in the gas space above the electrolysis medium. Long transport routes of the pure electrolysis gas should therefore be avoided in order to reduce the risk of explosion as much as possible. Mixing should preferably take place no later than 1 meter from the liquid surface,

particularly preferably at the latest at a distance of 50 centimeters from the liquid surface.

Preferably occurs the electrolysis gas - and of course also the optionally still unmixed oxygen gas and hydrogen gas - from the liquid surface into a gas chamber, in which the mixing with the additional gas takes place. This prevents the need for further transport of the unmixed and therefore explosive oxyhydrogen gas. Accordingly, it can be provided that the container has a gas chamber which, when the container is filled with electrolysis medium as intended, borders on a liquid surface of the electrolysis medium, and that the outlet is arranged on the gas chamber. The inlet can also be located at the gas chamber. It can also be below the liquid level when the container is filled as intended during normal operation.

It can also be provided that the mixing with the additional gas begins before the exit from the electrolysis medium. This can be achieved, for example, by introducing the additional gas into the electrolysis medium.

The additional gas is preferably itself combustible. Combustibility means that the gas in question can continue to burn with a suitable supply of oxygen after suitable ignition without additional fuels being necessary. Alternatively, it can also be provided that the additional gas is not combustible on its own, but that the gas mixture obtained from the method according to the invention is already combustible.

[0015] Lower hydrocarbons are understood to mean hydrocarbon compounds, preferably non-cyclic hydrocarbon compounds, particularly preferably alkanes, which have no more than 7 carbon atoms. So, for example, methane, ethane, propane, butane or pentane etc. are included. This group can also include cyclic hydrocarbons and/or those with double bonds, for example alkenes or multiple bonds such as alkynes.

The additional gas preferably consists at least predominantly of lower hydrocarbons and particularly preferably at least 80% by volume of lower hydrocarbons. It can be a mixture of lower hydrocarbons, for example natural gas, or pure lower hydrocarbons such as methane, propane or butane.

[0017] Percentage by volume or % by volume is understood as meaning the percentage by volume of a part of a mixture from the total volume of the mixture. It is therefore % vv.

It can be provided that the gases are mixed with one another in such a way that the resulting gas mixture has an oxygen content of at most 15% by volume, preferably at most 12% by volume, particularly preferably at most 10% by volume, and very particularly preferably at most 5%. This ensures that the gas mixture is non-explosive and safe to handle. Because the oxygen content largely determines how great the risk of explosion or ignition is.

In this sense, it can also be advantageous if it is provided that the resulting gas mixture has an oxygen content of at least 2% by volume, preferably at least 3% by volume. The oxygen content of the resulting gas mixture is particularly preferably between 3% by volume and 5% by volume.

It can also be advantageous if the gases are mixed with one another in such a way that the resulting gas mixture has a proportion of lower hydrocarbons of at most 95% by volume, preferably at most 90% by volume, particularly preferably at most 85% by volume, and entirely particularly preferably at most 80%.

It is particularly advantageous if the additional gas is guided along the liquid level of the electrolysis medium. This means that the electrolysis gas and possibly still pure oxygen and/or hydrogen gas are mixed with the additional gas immediately after it emerges from the liquid. By passing the additional gas along the surface

achieve a particularly good mix.

In this sense, it is advantageous if the electrolysis takes place in at least one container, also electrolysis container, in which the electrolysis medium is arranged and that the additional gas is introduced into a gas compartment above the liquid level of the electrolysis medium. In this way, mixing can take place directly upon exit.

In a preferred embodiment it is provided that the electrolysis takes place in a substantially gas-tight container and that additional gas is introduced into the container via at least one inlet and the gas mixture is carried out via at least one outlet and that preferably at least one inlet and at least one Outlet are arranged on substantially opposite sides of the container. Sufficient mixing can take place, in particular in the case of an opposite arrangement, without additional mixing devices such as fans, nozzles or flow obstacles being provided. The opposing arrangement ensures that the additional gas flows in on one side, along the surface of the liquid, and flows out again via the outlet, with the mixing with the electrolysis gas taking place automatically as a result of passing through the surface of the liquid. This also applies mutatis mutandis if it is provided that the container has at least one outlet for discharging the gas mixture and that preferably at least one outlet and at least one inlet are arranged on opposite sides of the container. It is important that they are arranged opposite one another in the plane of the liquid surface of the electrolysis medium so that the flow takes place along the surface.

It can be provided that the oxygen content and/or the hydrogen content of the gas mixture and/or the gas flow of the additional gas before mixing and/or the gas flow of the resulting gas mixture is measured and the amount of additional gas supplied and/or an electrolysis used power output is regulated depending on the measured values. This increases safety, since the risk of an explosive gas mixture forming can be prevented. For example, provision can be made for the electrolysis to be slowed down or switched off when the inflowing amount of additional gas falls below a limit value.

Preferably, the amount of supplemental gas is increased when the measured concentration of oxygen and/or hydrogen is too high. For example, this can be done with an upper limit value. Provision can furthermore be made for the amount of additional gas to be reduced if the measured concentration of oxygen and/or hydrogen or the measured flow rate of the gas mixture is too low. For example, this can be done using a lower limit value. Of course, it can also be provided that the amount of additional gas in the gas mixture is measured and the amount of additional gas supplied is regulated as a function of the measured values. What has just been said then also applies analogously.

It can be provided that the electrolysis device has at least one oxygen sensor and/or at least one hydrogen sensor in a gas compartment above the electrolysis medium, in the area of the outlet and/or downstream of the outlet and/or that the electrolysis device has in the area of the outlet and/or or downstream of the outlet and/or in the region of the inlet and/or upstream of the inlet has at least one flow meter for measuring the inflowing and/or outflowing quantity of gas. In this sense, it is particularly advantageous if a control device is provided for controlling the amount of additional gas flowing into the container, which is connected to the oxygen sensor and/or hydrogen sensor and/or at least one flow meter and is set up to determine the amount of additional gas as a function of the measured To regulate values of the oxygen sensor and/or hydrogen sensor and/or the measured gas flow. The statements in the last two paragraphs apply here as well.

[0027] The flow measurement is usually the measurement of the volume of gas transported per unit of time.

In addition, it can be provided that the electrolysis is exceeded when a limit temperature

temperature of the electrolysis medium and/or the gas mixture is switched off. This reduces the risk of self-ignition due to excessive operating temperatures. In this sense, it can be provided that at least one temperature sensor is provided for measuring the temperature of the electrolysis medium and/or the gas mixture, and that the temperature sensor is set up to end the electrolysis when a limit temperature is exceeded, for example at 50 °C.

Furthermore, efficient electrolysis is possible if it is provided that the electrolysis medium comprises water and that the electrolysis medium comprises at least one base and/or at least one acid and/or at least one salt, preferably sulfuric acid and/or potassium hydroxide and/or sodium sulfate.

For the most efficient electrolysis possible, it can be provided that several, preferably at least 10, particularly preferably 12, electrolysis units are arranged in the container and the electrolysis units are electrically connected in parallel with one another, that each electrolysis unit has at least one cathode and at least one anode, each are arranged together in one housing and that the electrolysis units are preferably independently controllable.

[0031] Independent controllability means that the amount of electricity introduced into the electrolysis units can be adjusted steplessly or in stages, or at least can be switched on and off, independently of the other units.

It is also advantageous if at least one electrolysis unit has a rectifier for rectifying an AC supply voltage of the electrolysis unit and that preferably all electrolysis units each have a rectifier. The rectifiers are supplied with an alternating voltage and make direct current available to the electrodes.

If it is provided that the housing of at least one, preferably all, electrolysis units has at least one, preferably two openings on a side facing the surface of the electrolysis medium, and at least one opening on a side facing away from the surface of the electrolysis medium, the resulting electrolysis gas Emerge via the at least one upper opening and fresh electrolysis medium can flow in via the at least one lower opening and a uniform flow can be achieved.

In order to make the electrolysis particularly efficient, it can be provided that at least one, preferably 9, electrically conductive plates are arranged between at least one cathode and at least one anode of the electrolysis device Anodes are electrically connected to each other only via the electrolysis medium and that this cathode is preferably designed as a cathode plate and this anode as an anode plate. The cathode plate, the anode plate and/or the electrically conductive plates are preferably made of a metal or an alloy, particularly preferably made of a steel such as Nirosta steel. If several electrolysis units are provided, it is preferably provided that each electrolysis unit has at least one cathode plate and one anode plate. Investigations by the inventors have shown that such an embodiment is particularly advantageous and efficient.

The cathode plate and anode plate are electrically conductive plates, which are connected to electrical supply lines and are supplied with electricity in order to carry out the electrolysis, so they serve as electrodes or are part of the electrodes. They are at least partially arranged in the electrolysis medium.

The invention is explained in more detail below using non-limiting figures. Show it:

1 shows a schematic representation of a first embodiment of an electrolysis device according to the invention in a section;

2 shows a schematic representation of an electrolysis unit of the embodiment in a perspective view;

[0039] FIG. 3 shows a detail of the electrolysis unit from FIG. 2 in a schematic section.

The embodiment of an electrolysis device 1 shown in FIG. 1 has a substantially tight container 2 in which liquid electrolysis medium 3 is arranged. Electrolysis medium 3 can be refilled via an inlet (not shown). The container 2 has an inlet 4 above the liquid surface in a gas compartment, ie a gas chamber, which is connected via a pipeline to an additional gas source 5, in this case a natural gas tank. On the side of the container 2 opposite the inlet 4, the latter has an outlet 6 which is arranged above the liquid surface and via which gas can be discharged from the container via pipelines, for example to an incinerator or to your collection tank.

In the container 2, a plurality of electrolysis units 7 are arranged upright next to one another, with only three being shown in FIG. 1 by way of example. Each electrolysis unit 7 has a housing 8 and a rectifier 9 arranged outside of the housing 8, with each rectifier 9 supplying its electrolysis unit with direct current. For this purpose, the rectifiers 9 are connected in parallel to an AC supply voltage line 10 .

The electrolysis units 7 are arranged in the container 2 in such a way that their plate-shaped electrodes 11, 12 stand upright in the container, which simplifies the discharge of the gas and saves space.

During operation, additional gas is fed from the additional gas source 5 into the gas space of the container 2 (arrow 20). The rectifiers 9 provide the electrodes 11, 12 with direct current, as a result of which water in the electrolysis medium 3 is converted into oxygen gas and hydrogen gas at these electrodes. This rises in the direction of the liquid surface in the electrolysis medium 3 and at least partially mixes to form electrolysis gas. The additional gas flows in via the inlet 4 and flows in the direction of the outlet 6, as a result of which it is guided directly along the liquid level by the arrangement opposite (arrows 21). As a result, it mixes with the electrolysis gas and the oxygen and hydrogen gas that are still unmixed. The resulting gas mixture is then discharged via the outlet 6 (arrow 22).

The inlet 4 and the outlet 6 each have flowmeters 24, 25 in the area of the container 2, via which the gas flow through the inlet 4 and outlet 6 along the pipelines is measured. By comparing the two values, conclusions can be drawn about the proportion of electrolysis gas and thus of oxygen and hydrogen in the gas mixture. A control device (not shown), which is connected to the flow meters 24, 25, a control valve 23 of the additional gas source 5 and the rectifier 9, controls the proportion of electrolysis gas and thus oxygen gas in the gas mixture. For this purpose it can be provided that it throttles the amount of electricity for the electrolysis if the proportion of additional gas and thus oxygen becomes too large and/or that it increases the amount of additional gas that is derived from the additional gas source 5 .

Figure 2 shows the housing 8 of an electrolysis unit 7 in detail, in this embodiment it is made of fiberglass. In this case, this housing 8 has two openings 8a on an upper side, that is to say the side facing the liquid surface, through which the electrolysis gas produced during the electrolysis can escape. On the opposite side, the underside, ie the side facing away from the liquid surface, there is an opening 8b through which the electrolysis liquid 3 can flow into the housing 8 . The housing 8 is essentially flat so that it can accommodate large disks in a space-saving manner and several housings 8 can be accommodated next to one another in the container 2 .

In Figure 3, part of the interior of a housing 8 of an electrolysis unit 7 is shown. It becomes visible that the positive and negative supply line, which conduct the direct current for the electrolysis to the electrodes 11, 12, on two opposite sides of the surface

Housing 8 are introduced into this. Inside the housing 8, a total of eleven metal plates are spaced apart and stacked, the first three on one side and the last on the other side being shown here only by way of example. The plates are all essentially the same size and adapted to the shape of the housing, being held in place by plastic holders 14 in an electrically insulated manner from one another. Spaces are provided above and below the plates 11, 12, 13, through which the electrolysis medium 3 can penetrate between the plates 11, 12, 13 and electrically connect them to one another.

The respective outermost plates 11, 12 of the stack are each electrically connected to a supply line of the rectifier 9 via connecting members 14, with which these act as electrodes 11, 12. The one connected to the negative pole acts as the cathode plate 11 and the one connected to the positive pole acts as the anode plate 12. The remaining plates 13 in between are electrically connected to the poles only via the electrolysis medium 3.

Claims (17)

patent claims 1. A process for the electrolytic preparation of an oxygen-containing and hydrogen-containing gas mixture, in which current is introduced into a liquid electrolysis medium (3) via electrodes (11, 12) and oxygen gas and hydrogen gas are thus generated, which are produced from the electrolysis medium (3) in at least partially mixed form exits as electrolysis gas, characterized in that immediately after exiting, the electrolysis gas is mixed with an additional gas, which comprises lower hydrocarbons, to form a gas mixture. 2. The method according to claim 1, characterized in that the gases are mixed with one another in such a way that the resulting gas mixture has an oxygen content of at most 15% by volume, preferably at most 12% by volume, particularly preferably at most 10% by volume, and very particularly preferably at most 5%. 3. The method according to claim 1 or 2, characterized in that the gases are mixed with one another in such a way that the resulting gas mixture has a proportion of lower hydrocarbons of at most 95% by volume, preferably at most 90% by volume, particularly preferably at most 85% by volume .-%, and very particularly preferably at most 80% by volume. 4. The method according to any one of claims 1 to 3, characterized in that the additional gas is guided along the liquid level of the electrolysis medium (3). 5. The method according to any one of claims 1 to 4, characterized in that the electrolysis takes place in at least one container (2) in which the electrolysis medium (3) is arranged and that the additional gas is fed into a gas compartment above the liquid level of the electrolysis medium (3). is introduced. 6. The method according to any one of claims 1 to 5, characterized in that the electrolysis takes place in a substantially gas-tight container (2) and that additional gas is introduced into the container (2) via at least one inlet (4) and the gas mixture via at least an outlet (6) and that preferably at least one inlet and at least one outlet (6) are arranged on substantially opposite sides of the container (2). 7. The method according to any one of claims 1 to 6, characterized in that the oxygen content and/or the hydrogen content of the gas mixture and/or the gas flow of the additional gas before mixing and/or the gas flow of the gas mixture is measured and the amount of additional gas supplied and /or a power output used for the electrolysis is controlled depending on the measured values. 8. The method according to any one of claims 1 to 7, characterized in that the electrolysis medium (3) comprises water and that the electrolysis medium (3) comprises at least one base and/or at least one acid and/or at least one salt, preferably sulfuric acid and /or caustic potash and/or sodium sulphate. 9. Electrolysis device (1) for the electrolytic production of an oxygen-containing and hydrogen-containing gas mixture, the electrolysis device (1) having at least one container (2) for receiving electrolysis medium (3) and electrodes (11, 12) arranged therein for introducing current into the electrolysis medium (3), characterized in that at least one inlet (4) of the container (2) is connected to an additional gas source (5) for supplying the container (5) with an additional gas comprising lower hydrocarbons. 10. Electrolysis device (1) according to claim 9, characterized in that the container (2) has at least one outlet (6) for discharging the gas mixture and that preferably at least one outlet (6) and at least one inlet (6) on opposite sides of the Container (2) are arranged. 11. The electrolysis device (1) according to claim 9 or 10, characterized in that the electrolysis device (1) has at least one oxygen sensor in a gas compartment above the electrolysis medium (3), in the region of the outlet (6) and/or downstream of the outlet (6). and/or has at least one hydrogen sensor. 12. Electrolysis device (1) according to one of claims 9 to 11, characterized in that the electrolysis device (1) in the area of the outlet (6) and/or downstream of the outlet (6) and/or in the area of the inlet (4) and /or upstream of the inlet (4) has at least one flow meter (24, 25) for measuring the inflowing and/or outflowing quantity of gas. 13. Electrolysis device (1) according to one of claims 11 or 12, characterized in that a control device for controlling the amount of additional gas flowing into the container (2) is provided, which is connected to the oxygen sensor and/or hydrogen sensor and/or at least one flow meter (24 , 25) and is set up to regulate the amount of additional gas depending on the measured values of the oxygen sensor and/or hydrogen sensor and/or the measured gas flow. 14. Electrolysis device (1) according to one of Claims 9 to 13, characterized in that several, preferably at least 10, electrolysis units (7) are arranged in the container (2) and the electrolysis units (7) are connected in parallel with one another, that each electrolysis unit (7 ) has at least one cathode (11) and at least one anode (12), which are each arranged together in a housing (8) and that the electrolysis units (7) can preferably be controlled independently of one another. 15. Electrolysis device (1) Claim 14, characterized in that at least one electrolysis unit (7) has a rectifier (9) for rectifying an AC supply voltage of the electrolysis unit (7) and that preferably all electrolysis units (7) each have a rectifier (9) for supply of the respective electrolysis unit (7). 16. Electrolysis device (1) Claim 14 or 15, characterized in that the housing (2) has at least one, preferably all, electrolysis units (7) on a side facing the surface of the electrolysis medium (3) at least one, preferably two, openings (8a) and has at least one opening (8b) on a side facing away from the surface of the electrolysis medium (3). 17. Electrolysis device (1) according to one of claims 9 to 16, characterized in that at least one, preferably 9, electrically conductive plates (13) are arranged between at least one cathode (11) and at least one anode (12) of the electrolysis device (1). which are electrically connected to one another and/or from the cathode (11) and/or from the anode (12) only via the electrolysis medium (3) and that this cathode (11) is preferably designed as a cathode plate and/or this anode (12 ) are designed as anode plates. 3 sheets of drawings