Method for operating an electrochemical plant, electrochemical plant

Abstract

The invention relates to a method for operating an electrochemical plant (1), in particular an electrolysis plant, comprising at least one stack (2), in particular an electrolysis stack, and components (3) for power supply, wherein the stack (2) is housed separately from the components (3) for power supply in a gas-tight sealed volume (4) filled with gas, in particular with air and / or an inert gas, and wherein, during operation of the electrochemical plant (1), a pressure (p1) prevailing in the volume (4) and / or a pressure (p2) prevailing in the environment or in a further volume (5) in which the components (3) for power supply are housed is / are adjusted such that the pressure (p1) is lower than the pressure (p2). The invention further relates to an electrochemical plant (1), in particular an electrolysis plant, which is suitable for carrying out the process or can be operated according to the process.

Description

[0001] The invention relates to a method for operating an electrochemical plant, in particular an electrolysis plant. Furthermore, the invention relates to an electrochemical plant, in particular an electrolysis plant, that is suitable for carrying out the method or operable according to the method.

[0002] The electrochemical system can be not only an electrolysis system, but also another electrochemical system, such as a fuel cell system. The invention is therefore not limited to electrolysis systems.

[0003] The preferred field of application of the invention is the production of hydrogen. State of the art

[0004] Electrolysis is an electrochemical process in which electrical current is used to break down a chemical compound. In the case of water electrolysis, hydrogen (H2) and oxygen (O2) are produced from water (H2O).

[0005] Electrolysis takes place in an electrolyzer. This comprises a large number of electrolysis cells connected to form a stack. Well-known examples include PEM electrolysis cells (where PEM stands for "Proton Exchange Membrane"), AEL electrolysis cells (where AEL stands for "Liquid Alkaline Electrolysis"), solid oxide electrolysis cells (SOECs ("Solid Oxide Electrolyzer Cell"), and AEM electrolysis cells (where AEM stands for "Anion Exchange Membrane"). Electrolysis in the electrolysis stack also requires a power supply, a water circuit, and gas treatment, each with the associated components and lines. The power supply typically includes a transformer for converting alternating current (AC) into direct current (DC), as well as a rectifier for adjusting the DC voltage.The water circuit typically includes water treatment to achieve the required low conductivity, a pump to supply the water, and gas-liquid separators to separate the product gases H2 and O2 from the water. The water circuit may also include additional filters, ion exchangers, sensors, and actuators. Gas treatment typically includes gas drying and purification. Additional components may also include an intermediate storage tank and a compressor.

[0006] Against the backdrop of decarbonization, hydrogen production from renewable energies is gaining increasing importance. In addition to a sheer increase in hydrogen electrolysis projects, the average size of the respective projects and thus the electrolysis systems to be implemented is also increasing. Since stack size is typically considered limited, modularization concepts for electrolysis systems are required that enable the construction and efficient operation of large plants based on a large number of stacks.

[0007] To comply with current safety regulations, such as the European Union's ATEX directives, the power supply is often located separately from the stack, for example, in a different room or on a different floor. This is intended to prevent gases or gas mixtures released through leakage from igniting due to sparks. If no spatial separation is provided, certain minimum distances must be maintained. All of these measures lead to increased cabling effort, particularly with regard to power and data cables. Costs increase due to the high material usage. Furthermore, efficiency losses occur due to the increased electrical resistance of the longer cables.

[0008] The present invention addresses the problem of reducing cable lengths while complying with applicable safety regulations in order to save costs and optimize the efficiency of the system, particularly at the interface between the power electronics and the stack. To achieve this problem, the method having the features of claim 1 and the electrochemical system having the features of claim 4 are proposed. Advantageous developments of the invention can be found in the respective subclaims. Disclosure of the invention

[0009] Method for operating an electrochemical plant, in particular an electrolysis plant, comprising at least one stack, in particular an electrolysis stack, and components for the power supply. The components for the power supply can in particular be a rectifier, a transformer and / or other electrical or electronic components. The stack is accommodated separately from the components for the power supply in a gas-tight volume filled with gas, in particular with air and / or an inert gas. During operation of the electrochemical plant, a pressure p1 prevailing in the volume and / or a pressure p2 prevailing in the environment or in another volume in which the components for the power supply are accommodated is / are adjusted such that the pressure p1 is lower than the pressure p2.

[0010] Because the pressure in the volume containing at least one stack is lower than ambient pressure or the pressure in the additional volume containing the power supply components, gas escaping from the stack is prevented from coming into contact with the power supply components. This means that there is no need to create a large spatial distance between the stack and the power supply components in order to reduce the risk of explosion and comply with currently applicable safety regulations. As a result, all cables, especially the power and data cables, can be kept short. These short cables reduce material costs. Furthermore, the efficiency of the system can be increased. The system can also be designed to be very compact.

[0011] Carrying out the process requires an electrochemical plant in which at least one stack is enclosed in a gas-tight manner. The housing must be gas-tight with respect to the environment and / or with respect to the second volume in which the components for the power supply are housed. The housing can be a box or container, for example. The second volume can be formed within the housing, but then separated from the first volume in a gas-tight manner. The second volume can also be formed in its own housing, or the environment can form the second volume. It is important that the pressure p1 is lower than the pressure p2 of the environment or the additional volume during operation of the electrochemical plant. For this purpose, an enclosure accommodating at least one stack that is gas-tight with respect to the environment is basically sufficient.

[0012] With multiple stacks, each stack can be housed in its own gas-tight volume. Alternatively, several stacks can be arranged together in a gas-tight volume. Ideally, the number of stacks per gas-tight volume is limited, for example, to eight, four, or two stacks per volume. A large number of stacks distributed across a large number of gas-tight volumes enables the creation of large, high-performance systems.

[0013] According to a preferred embodiment of the invention, to adjust the pressure p1, gas is extracted from the volume containing the at least one stack. This means that a negative pressure is deliberately created in the first volume containing the at least one stack. In this case, the power supply components do not need to be separately housed, but can be arranged in the environment outside the stack housing. The pressure p2 then corresponds to the ambient pressure. The gas extracted from the volume containing the at least one stack is preferably discharged in a controlled manner via an appropriately designed exhaust.

[0014] Alternatively or additionally, it is proposed that, to adjust the pressure p2, the volume containing the power supply components be pressurized with gas, in particular air and / or an inert gas. This means that the pressure in the second volume is increased compared to the pressure in the first volume. For this purpose, the power supply components would have to be housed in a gas-tight enclosure or in a gas-tight additional volume of the enclosure of the at least one stack. If an enclosure is selected that forms the first and second volumes, a particularly compact system can be created.

[0015] Furthermore, an electrochemical plant, in particular an electrolysis plant, is proposed, comprising - at least one stack, in particular an electrolysis stack, which is accommodated in a first volume filled with gas, in particular with air and / or an inert gas, and - Power supply components housed in a second volume. The power supply components may include, in particular, a rectifier, a transformer, and / or other electrical or electronic components.

[0016] The two volumes are separated from each other in a gas-tight manner. Furthermore, means are provided for reducing the pressure in the first volume and / or for pressurizing the second volume.

[0017] The proposed electrochemical system is particularly suitable for carrying out the previously described process or can be operated according to this process. The system can therefore achieve the same advantages. In particular, the at least one stack and the power supply components can be arranged in close proximity to one another, allowing for short power and / or data lines while complying with the relevant safety regulations.

[0018] The gas-tight separation of the two volumes can be achieved by making at least the volume containing the at least one stack gas-tight. Alternatively or additionally, the volume containing the power supply components can be gas-tight. For example, at least one gas-tight volume can be realized by a gas-tight enclosure in the form of a box or container. The enclosure can also form both volumes.

[0019] If the system comprises multiple stacks, each stack can be housed in its own gas-tight volume or together with at least one other stack in a gas-tight volume. For multiple stacks in a shared gas-tight volume, the number of stack volumes is preferably limited, for example, to eight, four, or two stacks per gas-tight volume. A large number of stacks distributed across multiple gas-tight volumes enables the creation of large, high-performance systems.

[0020] According to a preferred embodiment of the invention, the first volume and the second volume are separated in a gas-tight manner by a wall of a housing in which at least the first volume is formed. This means that at least the first volume is designed to be gas-tight. In the event of a leak, no gas can escape uncontrollably outside the volume. Instead, the leak can be removed in a targeted manner, for example, via a vent that generates the lower pressure. This prevents escaping gas from entering the second volume that houses the power supply components. The gas cannot therefore be ignited by a spark or the like.

[0021] In a further development of the invention, it is proposed that the wall has at least one gas-tight, integrated wall feedthrough for at least one power and / or data line. The necessary power supply to the at least one stack can then be ensured via the wall feedthrough. Furthermore, power and / or data lines can be routed to electrical parts and / or components that are installed in the stack or in the vicinity of the at least one stack. For example, data lines can be used to control valves. Furthermore, sensors integrated into the at least one stack or in the stack vicinity can transmit data to a control unit arranged outside the first volume.

[0022] Alternatively or additionally, it is proposed that the wall has at least one gas-tight integrated connection device for at least one power and / or data line. In contrast to the wall feedthrough, the power and / or data line ends at the connection device, so that the connection device must be designed such that it can conduct the power and / or the data through the wall. On the other side of the wall, the connection device can then be connected to a power and / or data line. Preferably, the connection device comprises at least one plug part. The plug part facilitates the connection of a power and / or data line. Furthermore, at least one plug part is preferably provided on both sides.

[0023] The invention and its advantages are described in more detail below with reference to the accompanying drawings. These show: Fig. 1 a schematic representation of an electrochemical plant according to the invention and Fig. 2 an enlarged section of the Fig. 1 in the area of ​​a connection for a power and / or data line. Detailed description of the drawings

[0024] The Fig. The electrochemical system 1 according to the invention shown in Figure 1 is an electrolysis system for generating hydrogen. The system 1 comprises at least one stack 2, which is accommodated in a first volume 4 of a housing 7, as well as components 3 for the power supply, which are accommodated in a second volume 5 of the housing 7. The two volumes 4, 5 are separated by a gas-tight wall 6. In the present case, the first volume 4 is also gas-tight.

[0025] The power supply components 3, which are located in the Fig. 1 are not specified in more detail, can comprise a rectifier, a transformer and / or other electrical or electronic components, such as contactors, switches, filters and the like. In an advantageous embodiment of the system 1, the power provided in volume 5 corresponds to the required power of the at least one stack 2 in volume 4, i.e. the modularization of both volumes 4, 5 is adapted. Alternatively, it is possible for several, for example two, volumes 4 to be supplied with power via one volume 5 or for the power supply to one volume 4 to occur via a combination of several volumes 5.

[0026] In the Fig. 1 not shown, but present, are means for pressure reduction, with the aid of which a pressure p1 in the first volume 4 can be set which is lower than a pressure p2 in the second volume 5.

[0027] The Fig. The system shown in Figure 1 may further comprise further components which are necessary for the functioning of an electrolysis system, for example a water treatment system, a fluid supply system and / or a device for separating the product gases from the fluid water.

[0028] The at least one stack 2 and the components 3 for the power supply are connected via at least one power and / or data line 8, wherein, according to the invention, the power line can be designed to be particularly short. The power and / or data line 8 is interrupted by a connection device 9, which is integrated in a gas-tight manner into the wall 6. In the present example, two further connection devices 9 are integrated into the wall 6, which enable the connection of further power and / or data lines 8.

[0029] Again Fig.2, the connection device 9 has a base plate 11 with a plug part 10. The base plate 11 rests on the side of the wall 6 facing the first volume 4 and is fastened thereto by means of fastening means 12, for example in the form of screws. The plug part 10 is guided through an opening in the wall 6 so that it projects on the other side of the wall 6 and enables the connection of a power and / or data line 8. At the other end, the plug part 10 is received in a connection plate 13 which is integrated into the base plate 11 and forms a receptacle for a further power and / or data line 8, wherein this receptacle can also be designed as a plug. The connection plate 13 can be made of metal, plastic or a composite material in order to ensure the required gas tightness.

Claims

[1] Method for operating an electrochemical plant (1), in particular an electrolysis plant, comprising at least one stack (2), in particular an electrolysis stack, and components (3) for the power supply, wherein the stack (2) is accommodated separately from the components (3) for the power supply in a gas-tight, sealed volume (4) filled with gas, in particular with air and / or an inert gas, and wherein during operation of the electrochemical plant (1) a pressure (p1) prevailing in the volume (4) and / or a pressure (p2) prevailing in the environment or in a further volume (5) in which the components (3) for the power supply are accommodated is or are set such that the pressure (p1) is lower than the pressure (p2). [2] Method according to claim 1, characterized by that, in order to adjust the pressure (p1), gas is sucked out of the volume (4) accommodating at least one stack (2). [3] Method according to claim 1 or 2, characterized by that in order to adjust the pressure (p2) the volume (5) accommodating the components (3) for the power supply is pressurized with gas, in particular with air and / or inert gas. [4] Electrochemical plant (1), in particular electrolysis plant, comprising - at least one stack (2), in particular an electrolysis stack, which is accommodated in a first volume (4) which is filled with gas, in particular with air and / or an inert gas, and - components (3) for power supply, which are accommodated in a second volume (5), wherein the two volumes (4, 5) are separated from each other in a gas-tight manner, and wherein means for reducing the pressure in the first volume (4) and / or means for pressurizing the second volume (5) are present. [5] Electrochemical plant (1) according to claim 4, characterized bythat the first volume (4) and the second volume (5) are separated in a gas-tight manner by a wall (6) of a housing (7) in which at least the first volume (4) is formed. [6] Electrochemical plant (1) according to claim 5, characterized by that the wall (6) has at least one gas-tight integrated wall feedthrough for at least one power and / or data line (8). [7] Electrochemical plant (1) according to claim 5 or 6, characterized by that the wall (6) has at least one gas-tight, integrated connection device (9) for at least one power and / or data line (8), wherein the connection device (9) preferably comprises at least one plug part (10).

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