Method for operating an electrochemical plant, control unit

Abstract

The invention relates to a method for operating a modular electrochemical plant (1), in particular an electrolysis plant, comprising several modules (2), each with at least one stack (3), a sensor (4), and a control unit (5), as well as a central control unit (6) connected to the control units (5) of the modules (2) in a data-transmitting manner for controlling the plant (1). According to the invention, data acquired locally by means of the sensor (4) of a module (2) are pre-processed and / or pre-evaluated locally by means of the control unit (5) of the respective module (2). The invention further relates to a control unit (5) for a module (2) of a modular electrochemical plant (1).

Description

The invention relates to a method for operating an electrochemical plant, in particular an electrolysis plant. The invention also relates to a control device for executing steps of the method.A preferred field of application of the invention is the generation of hydrogen by electrolysis. Further areas of application are fuel cell systems, in particular stationary fuel cell systems, for generating electrical energy.Prior ArtElectrolysis refers to a chemical process in which electric current is used to split a chemical compound. Hydrogen and oxygen can thus be obtained from water.To carry out the electrolysis, at least one electrolysis cell is required, for example a PEM ("proton exchange membrane") electrolysis cell, an AEL ("liquid alkaline electrolysis") electrolysis cell, a solid oxide electrolysis cell or SOEC ("solid oxide electrolyte cell") or an AEM ("anion exchange membrane") electrolysis cell, wherein the electrolysis cells mentioned differ in the type of ionic conductivity.As a rule, a plurality of identical electrolysis cells are placed one above the other and connected to form a cell stack, the so-called stack. This requires further components, in particular those for supplying current and water and for gas treatment. The components for the power supply usually comprise a transformer for converting AC into DC and a rectifier for adapting the DC voltage. The components for supplying water comprise at least one water circuit and a pump. The components for gas treatment comprise gas-liquid separators in order to separate the product gases hydrogen and oxygen from water. In addition, means for controlling and / or regulating the system are required.Against the background of decarbonization, hydrogen is becoming increasingly important as an energy carrier. The aim is currently being pursued of producing green hydrogen, i.e. hydrogen with very low CO 2- footprint, by electrolysis on a large industrial scale, preferably with installations beyond the multi-MW or the 1 GW power. Since a single stack cannot grow unlimitedly with the performance of a plant for several reasons, for example for reasons of weight, reliability and skills, several stacks are required. Modularization of such installations has developed, wherein a module can consist of a single stack, a plurality of stacks or a complete system, that is to say at least one stack including a power and water supply and a gas treatment. Presently known modular plants for electrolysis usually consist of modules with a plurality of stacks which are electrically connected in series within the respective module. In addition, a central media supply is often provided for the use of scaling effects.During operation of an electrochemical plant of modular construction, a large number of data, in particular operating and status data, are recorded with the aid of a suitable sensor system. The data are then processed and evaluated with the aid of a central control unit. With the size of the electrochemical plant, the amount of data that must be processed and evaluated necessarily also increases. This means that higher computing powers and / or longer computing times are required.The present invention is concerned with the object of reducing the data load during operation of an electrochemical plant, in particular of an electrolysis plant, and at the same time improving the data quality.To achieve the object, the method having the features of claim 1 is proposed. Advantageous further developments of the invention can be found in the dependent claims. Furthermore, a control device for executing steps of the method is proposed.Disclosure of the InventionA method for operating an electrochemical plant of modular construction, in particular an electrolysis plant, is proposed, which comprises a plurality of modules each having at least one stack, one sensor system and one control device, and a central control unit for controlling the plant, which central control unit is connected to the control devices of the modules in a data-transmitting manner. According to the invention, data locally recorded by means of the sensor system of a module are locally preprocessed and / or prevaluated with the aid of the control unit of the respective module.The central control unit is relieved by the local preprocessing and / or pre-evaluation of the locally captured data. This can therefore be designed for a lower computing power and / or the data quantity can be increased, for example for expanding the installation.After preprocessing or pre-evaluation of the data locally detected with the aid of the sensor system of a module, the data can be selected which are forwarded to the central control unit. In this way, the data stream in the direction of the central control unit can be reduced. This in turn enables a higher resolution (quantization) and / or a higher sample rate (frequency) of the data, since the bus load in the individual communication lines is lower. At the same time, an improvement in the data quality can be achieved.In a further development of the invention, it is proposed that the preprocessing and / or preliminary evaluation of the locally captured data comprises a qualification with regard to its relevance for the control of the installation and only the data qualified as relevant are transmitted to the central control unit. The data stream in the direction of the central control unit can be further reduced in this way. Preprocessed and / or pre-evaluated data that are not transmitted to the central control unit may be further processed and / or evaluated at the module level with the aid of the control unit of the respective module.Furthermore, it is proposed that data detected locally by means of the sensor system of a module and qualified as not relevant for the control of the installation are stored locally and / or transmitted to a cloud. Both the local storage and the transmission of the data to a cloud enable a simplified, unique assignment of the data to a specific module within the installation ("data integrity"), which is advantageous in particular when the installation is set up and / or after a handling of the installation. In addition to data confidentiality and availability, data integrity is an essential prerequisite for the usability of local state determinations for the further targeted processing of the data.The locally recorded data can be stored locally, for example, in a data memory of the control unit. For this purpose, the control device can comprise a hard disk or an SSD card.The cloud may be a data storage of an external or internal network. The interface for transmitting the data to the cloud can be an edge device, for example.Ideally, locally acquired data is both stored locally and transmitted to a cloud. This is because in the case of an erroneous or for other reasons problematic data transmission to the cloud, the local data storage can be used to keep the data available.Data are preferably locally acquired by means of the sensor system of a module, which data are specific to the state and / or operation of the respective module or a component of the module. The data can relate, for example, to the state and / or operation of the at least one stack of the module and / or to power electronics connected to the stack. The data relating to the stack or stacks can comprise, for example, the stack voltage, the single cell voltage, the temperatures of the various media streams or the temperature difference, the local pressure or the pressure difference between anode inlet and anode outlet or between anode and cathode. The data relating to the power electronics can relate in particular to the power output, the current or the current density.In the proposed method, a distinction is therefore preferably made between two types of data, namely those which are relevant for the plant operation and those which relate to the state / operation of a module or of a component of the module. The latter are not only detected locally, but also processed locally and preferably stored. A simplification is obtained in this case in that each module of the installation has its own sensor system and its own control device. In addition, each module can comprise its own power electronics and / or its own actuator system.In a development of the method, it is proposed that data, for example operating data of the installation or other installation-specific data, be transmitted from the central control unit to the control units of the modules. The data transmission between the local control units and the central control unit accordingly takes place in both directions. This means that a data exchange takes place. The data transmitted from the central control unit to a local control device can then be transmitted to a cloud together with the locally captured data.In addition, a control device for a module of an electrochemical plant of modular construction, in particular an electrolysis plant, is proposed. The control device is configured to execute steps of a method according to the invention. In particular, with the aid of the control unit, preprocessing and / or pre-evaluation of data acquired locally or at the module level can be carried out. The preprocessing and / or preliminary evaluation can comprise a qualification of the data, in particular for a subsequent selection of the data which have relevance for the control of the electrochemical installation. Only these data are then transmitted from the control unit to a central control unit of the system.According to a preferred embodiment of the invention, the control device has a data memory and / or an interface for data transmission to a central control unit and / or to a cloud. The data memory can be, for example, a hard disk or an SSD card. The interface for data transmission can be realized in particular by an edge device.The invention and its advantages are described in more detail below with reference to the attached drawings. This shows a schematic illustration of an electrochemical plant according to the invention.DETAILED DESCRIPTION OF THE DRAWINGThe figure shows an electrochemical plant 1 in the form of an electrolysis plant which serves for the production of hydrogen. The installation 1 is of modular construction, wherein the installation 1 illustrated comprises, by way of example, three modules 2. However, the number of modules 2 may vary and is not set to three. Each module 2 has at least one stack 3, a sensor system 4, power electronics 10, an actuator system 11 and a control unit 5 with a data memory 7. The control units 5 can each transmit data to a central control unit 6 of the installation 1 and to an external cloud 8 via a communication interface 9. The control units 5 can also receive data which are transmitted to them by the central control unit 6.Not shown in the figure are components and lines serving for supplying the media and the power to the modules 2 and components for processing the product gases.During operation of the system 1 shown, data relating to the state and / or operation of the respective module 2 or one of its components are respectively recorded at the module level with the aid of the sensor system 4. The locally recorded data are preprocessed and / or prevaluated with the aid of the control unit 5 of the respective module 2. In this case, the relevance of the data for the plant operation or the control of the plant 1 is simultaneously recorded. This makes it possible to distinguish the data into data relevant for the plant operation and data not relevant for the plant operation. Only the data relevant for the operation of the installation are then transmitted from the control unit 5 to the central control unit 6. All other data are stored locally in the data memory 7 of the control unit 5 and / or transmitted to the cloud 8.In this way, the amount of data that arises at the central control unit can be reduced. The preprocessing and / or pre-evaluation of the data at the module level results in less computing power being bound by the central control unit, which is then available for other purposes. Alternatively, a central control unit with a lower power can be used, since the amount of data occurring there is reduced.

Claims

Method for operating an electrochemical plant (1) of modular construction, in particular an electrolysis plant, which comprises a plurality of modules (2) each having at least one stack (3), a sensor system (4) and a control unit (5) and a central control unit (6) for controlling the plant (1) which is connected to the control units (5) of the modules (2) in a data-transmitting manner, characterized in that data detected locally by means of the sensor system (4) of a module (2) are locally preprocessed and / or prevaluated with the aid of the control unit (5) of the respective module (2).Method according to Claim 1, characterized in that the preprocessing and / or preliminary evaluation of the locally captured data comprises a qualification with regard to its relevance for the control of the installation (1) and only the data qualified as relevant are transmitted to the central control unit (6).Method according to Claim 1 or 2, characterized in that data detected locally by means of the sensor system (4) of a module (2) and qualified as data not relevant for the control of the installation (1) are stored locally and / or transmitted to a cloud (8).Method according to one of the preceding claims, characterized in that data which are specific for the state and / or operation of the respective module (2) or a component of the module (2) are locally captured by means of the sensor system (4) of a module (2).Method according to one of the preceding claims, characterized in that data, for example operating data of the installation (1) or other installation-specific data, are transmitted from the central control unit (6) to the control units (5) of the modules (2).Control device (5) for a module (2) of a modular electrochemical installation (1), in particular an electrolysis installation, wherein the control device (5) is configured to carry out steps of a method according to one of the preceding claims.Control device (5) according to Claim 6, characterized in that the control device (5) has a data memory (7) and / or an interface (9) for data transmission to a central control unit (6) and / or to a cloud (8).

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