Volume measurement in a gas storage tank and gas storage

Abstract

The invention relates to a method for measuring the volume of a first gas space and / or a second gas space in a gas storage tank (10) with an outer shell (30). In this method, the first gas space (G1), which is delimited by at least one movable membrane (20), is filled with a first gas. The second gas space (G2), also delimited by the at least one movable membrane (20), is filled with a second gas. Once the gas spaces are filled, the position of the membrane (20) separating the first gas space (G1) and the second gas space (G2) is determined. Based on the determined position values, the volume of the first gas space (G1) and / or the second gas space (G2) is calculated. For the position determination, the movable membrane (20) forms a surface that defines a plane (E), wherein the plane (E) is or forms the boundary between the first gas space (G1) and the second gas space (G2).The position of the membrane within the gas storage (10) is also determined with respect to at least one measuring point (M1 / M2), preferably using an optical, mechanical, acoustic and / or electrical measuring method.

Description

[0001] The invention relates to a method for measuring volume in a gas storage tank according to claim 1 and a gas storage tank according to claim 11.

[0002] Gas storage facilities, especially those for biogas, natural gas or hydrogen, are known.

[0003] The prior art also describes methods for determining the gas volume stored in gas storage tanks. These methods use optical or mechanical techniques to determine the position of a membrane that limits the gas volume and then infer the enclosed volume from this measurement. However, these methods reach their limits, particularly with non-homogeneous gas distributions within the gas space. Gases that are lighter than air, in particular, exert a buoyant force within the storage tank, causing a bubble to form. This makes the gas volume difficult to measure because a correlation between the measurable storage height and the contained volume is virtually impossible. For gas storage tank operators, however, it is crucial to know the gas supply as accurately as possible.

[0004] The purpose of the invention is to improve the state of the art.

[0005] The problem is solved according to the invention with a method for measuring volume in a gas storage tank according to claim 1 and with a gas storage tank according to claim 11.

[0006] Embodiments are the subject of the dependent claims and the embodiments.

[0007] According to the invention, a method for measuring the volume of a first gas space and a second gas space in a gas storage tank with an outer shell is proposed, the method comprising: ▪ Filling the first gas space, which is bounded by at least one movable membrane, with a first gas, ▪ Filling the second gas space, which is separated by at least one movable membrane, with a second gas, ▪ Determining the position of the membrane separating the first gas space and the second gas space, ▪ Calculation of the volume of the first gas space and the second gas space based on the position of the membrane within the gas storage tank.

[0008] Determining the volume of non-static gas spaces is solved according to the invention by precisely determining the dynamic component of the gas space. The inventive proposal includes a method as described above, as well as a proposal in which the second gas space is first filled with a second gas before the first gas space is filled with a first gas.

[0009] In one possible design, the outer shell is constructed as a multi-layered membrane roof and pressurized to ensure a constant shape, whereby the process is carried out as described.

[0010] In another embodiment, the membrane is formed in the outer shell and the method is carried out according to the other proposal, wherein the filling of the second gas space takes place first and the membrane lying in the outer shell is supported by the filled second gas.

[0011] The method according to the invention is preferably used for storing gases that have a lower specific gravity than the air surrounding the storage unit, for example, natural gas or hydrogen, whereby the function of the gas spaces within the gas storage unit is reversed. The first gas space for storing the first, preferably lighter, gas is located above the second gas space, which contains a second gas with a higher specific gravity. This places the heavier gas below the lighter gas, with the two gas spaces, and thus the two gases, separated by the movable membrane. If the gas spaces are now filled from top to bottom, the membrane is supported by the second, heavier gas and thereby brought into an almost horizontal plane, the position of which within the gas storage unit can be measured. Based on these measurements, the volume of the second gas can be calculated very precisely.

[0012] Typically, the movable membrane forms a surface which defines a plane.

[0013] To ensure the membrane reliably forms a flat surface, it is advantageous to have a device in the gas storage tank that keeps the membrane under tension. Alternatively, the membrane can have its own inherent tension or be designed so that its own weight pulls it into tension and thus flat.

[0014] In a particularly advantageous design, the plane forms the boundary between the first gas space and the second gas space.

[0015] The difficulties in determining the volume of dynamic gas spaces stem primarily from the fact that the membranes that bound them do not assume a defined shape. Light gases, in particular, tend to form a bubble within the membrane, making precise volume determination impossible. By defining a plane, the position of this bubble can be precisely determined, and the volume calculated from that position.

[0016] According to a further training, the position of the membrane within the gas storage tank is determined in relation to at least one measuring point.

[0017] In one variant, at least one measuring point is defined by a highest point of the gas storage tank.

[0018] In another variant, at least one measuring point is defined by a lowest point of the gas storage, preferably by a base area in the gas storage.

[0019] Given a known distance to a fixed reference point, the volume of the gas spaces separated by the membrane can be precisely determined because the external shape of the gas storage is known.

[0020] Typically, the position of the membrane is detected and / or determined using an optical, mechanical, acoustic and / or electrical method.

[0021] In a particularly advantageous variant, the method for measuring distance is a laser distance measurement.

[0022] According to further training, the first gas is lighter than the second gas.

[0023] In another training course, the first gas chamber is filled with the lighter gas.

[0024] In one variant, the second gas space forms a supporting gas space.

[0025] In another variant, the second gas chamber is filled with the second gas as a support gas.

[0026] In a particularly advantageous variant, the second gas is air.

[0027] If the first gas chamber is filled with the first lighter gas, while the second gas chamber contains the second heavier gas, the separating movable membrane is held in an almost horizontal plane due to the different densities of the gases. The height of this plane, and thus the height of the membrane relative to a reference point, can be measured. Based on this measurement, the storage volume of the first gas chamber and / or the second gas chamber can be determined relatively accurately.

[0028] Typically, position determination is carried out before and / or after the introduction and / or discharge of a gas into the gas storage facility.

[0029] Advantageously, the position determination is carried out in real time.

[0030] In a particularly advantageous design, the gases are introduced into the gas spaces from above and / or below the membrane.

[0031] Introducing the gases into the respective gas spaces from above or below the membrane ensures a rapid and uniform formation of the separation plane formed by the movable membrane.

[0032] In a further training course, the first gas is introduced into the first gas space via a supply line in the area above the membrane.

[0033] In another training method, the second gas is fed into the second gas space via a supply line in the area below the membrane.

[0034] Typically, pressure measurements are taken in the gas spaces.

[0035] In dynamic gas spaces, the dynamic element, in this case the membrane, exerts pressure on the stored volume. Therefore, pressure measurement is advantageous for precise volume determination.

[0036] Advantageously, the pressure measurement is performed in real time.

[0037] In one variant, when gas is introduced into the first gas chamber, gas is removed or released from the second gas chamber. Conversely, when gas is removed from the first gas chamber, gas is introduced into the second gas chamber. This ensures that the movable membrane always moves within a defined plane, the height of which is determined relative to a measuring point.

[0038] In another variant, the measured pressures are regulated to a setpoint value via the supply and / or discharge of gas into at least one gas space, comprising the group consisting of the first gas space and the second gas space.

[0039] In a training exercise, at a defined overpressure, the second gas from the second gas chamber is discharged or released via a check valve in the supply line. At a defined underpressure, the second gas is fed or introduced into the second gas chamber via the check valve in the supply line.

[0040] In a particularly advantageous embodiment, when gas is introduced and / or discharged into the first and / or second gas space, the volume introduced and / or discharged is determined, preferably by means of a volume flow measurement.

[0041] Typically, the sum of the volumes of the two gas spaces lies within a defined range.

[0042] In a training course, gas is removed from the second gas chamber (G2) when the value is exceeded.

[0043] In another training course, if the value falls below a certain threshold, gas is directed into at least one gas chamber, comprising the group consisting of the first gas chamber and the second gas chamber.

[0044] The invention comprises a gas storage device for storing gas, with an outer shell in which at least two chambers are formed, separated from each other by a membrane, wherein a first chamber is configured as the first gas space and a second chamber as the second gas space, characterized in that the volume of at least one gas space can be determined via the position of the membrane within the outer shell. This also contributes to ensuring that the movable membrane is always reliably located in a measurable plane and that the volume in the gas spaces can be calculated precisely.

[0045] Advantageously, the first gas space is formed above the second gas space.

[0046] Typically, the membrane runs essentially horizontally between the gas spaces.

[0047] In a further training course, the second gas space is designed as a support gas space for the membrane.

[0048] In another advanced training, at least one device for determining the position of the membrane within the outer shell is provided.

[0049] Typically, at least one pressure gauge is present to determine the pressure within the gas spaces.

[0050] In one variant, at least one device for determining the volume of gas supplied and / or discharged is present in each supply line.

[0051] Advantageously, an evaluation unit is available for calculating the gas volume of the first and / or the second gas space.

[0052] According to one variant, the evaluation unit uses the position values ​​of the diaphragm determined by the device and / or the pressure gauge to calculate the gas volume or gas volumes.

[0053] In another variant, a display device is provided which shows the gas volumes calculated by the evaluation unit.

[0054] As a solution according to the invention, a gas storage device for storing gas is further proposed, with an outer shell in which at least two chambers are formed which are separated from each other by means of a membrane, wherein a first chamber is formed as the first gas space and a second chamber as the second gas space, and wherein the volume of at least one gas space can be determined via the position of the membrane within the outer shell.

[0055] The first gas space is preferably formed above the second gas space, wherein the membrane runs essentially horizontally between the gas spaces and wherein the second gas space is designed as a support gas space for the membrane.

[0056] Another important embodiment of the invention provides that at least one device for determining the position of the membrane within the outer shell is available.

[0057] A further embodiment of the invention provides that an evaluation unit is available for calculating the gas volume of the first and / or the second gas space, wherein the evaluation unit uses the position values ​​of the membrane determined by the device for calculating the gas volume or gas volumes.

[0058] A display device shows the values ​​of the gas volume or gas volumes calculated by the evaluation unit.

[0059] The values ​​calculated by the device can also be forwarded, if required, to an external display device or a device that can display the calculated values, e.g. via a data line or a radio connection.

[0060] The method according to the invention is preferably used in a gas storage tank according to the invention.

[0061] Further features, details and advantages of the invention will become apparent from the wording of the claims and from the following description of exemplary embodiments with reference to the drawings. The drawings show: Fig. 1 a schematic representation of a gas storage facility for carrying out the method according to the invention, Fig. 2 of the gas storage facilities of Fig. 1 without filling, Fig. 3 of the gas storage facilities of Fig. 1 to 40% filled with a light gas, and Fig. 4 of the gas storage facilities of Fig. 1 to 100% filled with a light gas.

[0062] In the figures, identical or corresponding elements are designated with the same reference symbols and are therefore not described again unless otherwise appropriate. Features already described are not described again to avoid repetition and apply to all elements with the same or corresponding reference symbols, unless explicitly excluded.

[0063] The disclosures contained in this entire description are transferable analogously to identical parts with the same reference numerals or component designations. Furthermore, the positional designations chosen in the description, such as top, bottom, side, etc., refer to the figures directly described and illustrated and must be applied analogously to any change in position.

[0064] Furthermore, individual features or combinations of features from the different exemplary embodiments shown and described can also represent independent, inventive or inventive solutions.

[0065] The Fig. Figure 1 shows a gas storage tank 10 with an outer shell 30 for carrying out the method according to the invention. The first gas chamber, K1, is filled with gas via a supply line Z1, followed by the filling of the second gas chamber, K2, via the supply line Z2. The membrane 20 now forms a plane E between the two gas chambers, and its position relative to a measuring point M1 / M2 can be determined by means of a distance sensor 40. An evaluation unit 60 determines the volume and displays it on a display unit 70. The introduced volumes are determined by devices for measuring the volume flow rate 90 in the supply lines. Pressure gauges 50 allow precise volume determination even when the gas chambers are pressurized. A check valve 80 effectively prevents overpressure in the gas chambers.

[0066] The Fig. Figures 2 to 4 illustrate the implementation of the procedure using one design of the gas storage facility as an example. Fig. 2. The gas storage tank is empty, in the sense that it contains no gas to be stored, but only support gas in the second gas chamber to maintain the outer contour. The distance between measuring point M2 and the membrane, which rests against the outer shell 30, is at its maximum.

[0067] Fig. Figure 3 shows the state of the storage tank at approximately 40% fill volume. The first gas chamber G1 has now formed, and the distance between the plane E spanned by membrane 20 and measuring point M2 has decreased.

[0068] Fig. Figure 4 shows the gas storage tank in its completely filled state. The membrane 20 rests on the base of the tank, and the distance to the measuring point is minimal. The outer shell is supported exclusively by the gas stored in the first gas chamber G1.

[0069] The invention is not limited to one of the embodiments described above, but can be modified in many ways.

[0070] It is evident that a method for determining the volume of a first gas space and / or a second gas space in a gas storage tank 10 with an outer shell 30 is proposed. In this method, the first gas space G1, delimited by at least one movable membrane 20, is filled with a first gas. The second gas space G2, also delimited by the at least one movable membrane 20, is filled with a second gas. Once the gas spaces are filled, the position of the membrane 20 separating the first gas space G1 and the second gas space G2 is determined. Based on the determined position values, the volume of the first gas space G1 and / or the second gas space G2 is calculated.

[0071] For position determination, the movable membrane 20 forms a surface which defines a plane E, wherein the plane E is or forms the boundary between the first gas space G1 and the second gas space G2. The position of the membrane within the gas storage 10 is also determined with respect to at least one measuring point M1 / M2, preferably using an optical, mechanical, acoustic and / or electrical measuring method.

[0072] Particular advantages of the method according to the invention result from the fact that the first gas is lighter than the second gas, wherein the first gas space G1 is filled with the light gas and wherein the second gas space G2 is filled with the heavy gas, so that the second gas space G2 forms a support gas space for the movable membrane 20.

[0073] It is also advantageous if, when gas is introduced into the first gas space G1, gas is removed or drained from the second gas space G2, and if, when gas is removed from the first gas space G1, gas is introduced into the second gas space G2, so that the movable membrane between the gas spaces G1, G2 always forms a substantially flat surface.

[0074] A gas storage device 10 according to the invention for storing gas has an outer shell 30 in which at least two chambers K1, K2 are formed, which are separated from each other by means of a membrane 20. A first chamber is designed as the first gas space G1 and a second chamber K2 is designed as the second gas space G2, wherein the volume of at least one gas space G1, G2 can be determined via the position of the membrane 20 within the outer shell 30, preferably by the method described above.

[0075] Advantageously, the first gas space G1 is formed above the second gas space G2, wherein the membrane 20 runs essentially horizontally between the gas spaces G1, G2 and wherein the second gas space G2 is designed as a support gas space for the membrane 20.

[0076] A device 40 serves to determine the position of the membrane 20 within the outer shell 30. An evaluation unit 60 takes over the position values ​​determined by the device 40 and uses them to calculate the gas volume of the first and / or the second gas space G1, G2.

[0077] A display device 70 is provided to display the gas volumes calculated by the evaluation unit 60.

[0078] All features and advantages arising from the claims, the description and the drawing, including design details, spatial arrangements and process steps, can be essential to the invention both individually and in various combinations.

[0079] The invention encompasses all combinations of at least two of the features disclosed in the description, the claims and / or the figures.

[0080] To avoid repetition, features disclosed by the device itself shall also be deemed disclosed by the process and be claimable. Likewise, features disclosed by the process shall be deemed disclosed by the device itself and be claimable. Reference symbol list 10 gas storage tanks 20 Membran 30 Outer shell 40 distance meters 50 pressure gauges 60 evaluation units 70 Display device 80 Check valve 90 volume flow meters K1 Chamber 1 K2 Chamber 2 G1 Gas space 1 G2 Gas Room 2 Level E M1 Measuring point 1 M2 measuring point 2 Z1 Supply line 1 Z2 supply line 2

Claims

[1] Method for measuring the volume of a first gas space (G1) and a second gas space (G2) in a gas storage tank (10) with an outer shell (30), the method comprising: ▪ Filling the first gas space (G1), which is bounded by at least one movable membrane (20), with a first gas, ▪ Filling the second gas space (G2), which is separated by at least one movable membrane (20), with a second gas, ▪ Position determination of the membrane (20) separating the first gas space (G1) and the second gas space (G2), ▪ Calculation of the volume of the first gas space (G1) and / or the second gas space (G2) based on the position of the membrane (20) within the gas storage (10). [2] Method according to claim 1, characterized by , that the movable membrane (20) forms a surface which defines a plane (E), wherein the plane (E) is or forms the boundary between the first gas space (G1) and the second gas space (G2). [3] Method according to claim 1 or 2, characterized by , that the position of the membrane within the gas storage (10) is determined with respect to at least one measuring point (M1 / M2). [4] Method according to claim 3, characterized by , that the at least one measuring point (M1) is defined by a highest point of the gas storage (10), or that the at least one measuring point (M2) is defined by a lowest point, preferably on a base surface of the gas storage (10). [5] Method according to any one of the preceding claims, characterized by , that the position of the membrane (20) is detected and / or determined by an optical, mechanical, acoustic and / or electrical method. [6] Method according to any of the preceding claims, characterized by , that the first gas is lighter than the second gas, wherein the first gas space (G1) is filled with the light gas and wherein the second gas space (G2) is filled with the heavy gas. [7] Method according to any of the preceding claims, characterized by , that the second gas space (G2) forms a support gas space. [8] Method according to any one of the preceding claims, characterized by , that a position determination is carried out before and / or after the introduction and / or discharge of one of the gases into the gas storage (10), wherein the gases are introduced into the gas spaces (G1, G2) from above and / or below the membrane. [9] Method according to any one of the preceding claims, characterized by , that when gas is introduced into the first gas space (G1), gas is removed or released from the second gas space (G2). [10] Method according to any of the preceding claims, characterized by , that when gas is withdrawn from the first gas space (G1), gas is admitted into the second gas space (G2). [11] Gas storage device (10) for storing gas, with an outer shell (30) in which at least two chambers (K1, K2) are formed, which are separated from each other by means of a membrane (20), wherein a first chamber is formed as the first gas space (G1) and a second chamber (K2) as the second gas space (G2), characterized by , that the volume of at least one gas space (G1, G2) can be determined via the position of the membrane (20) within the outer shell (30). [12] Gas storage tank according to claim 11 characterized by , that the first gas space (G1) is formed above the second gas space (G2), wherein the membrane (20) runs substantially horizontally between the gas spaces (G1, G2) and wherein the second gas space (G2) is formed as a support gas space for the membrane (20). [13] Gas storage tank according to claim 11 or 12, characterized by , that at least one device (40) for determining the position of the membrane (20) within the outer shell (30) is provided. [14] Gas storage device according to any one of claims 11 to 13, characterized by , that an evaluation unit (60) is provided for calculating the gas volume of the first and / or the second gas space (G1, G2), wherein the evaluation unit (60) uses the position values ​​of the membrane (20) determined by the device (40) for calculating the gas volume or gas volumes. [15] Gas storage device according to any one of claims 11 to 14, characterized by , that a display device (70) is provided which displays the gas volumes calculated by the evaluation unit (60).

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