Process and plant for the production and use of hydrogen

Abstract

The invention relates to a method and a system for the production and use of hydrogen, in particular for the use of hydrogen in electroplating. A climate-positive electroplating process is presented with the aim of reducing the CO2 footprint of an electroplating process by using an innovative combination of existing methods and the utilization of the previously unused gas mixture (contaminated H2).

Description

[0001] The invention relates to a method and a plant for the production and use of hydrogen, in particular for the use of hydrogen in the field of electroplating.

[0002] In electroplating processes for the electrolytic deposition of coatings onto objects, such as chrome or nickel plating, hydrogen and oxygen can be produced as process gases. In conventional plants, these process gases are often discharged with the exhaust air. In such conventional electroplating processes, a very large proportion, sometimes around 70%, of the energy used for the process is expended on the generation of these process gases, while only a significantly smaller proportion of the electricity is used for the actual electrolytic deposition of coatings, including heat generation. In addition to the process gas, waste heat is also generated as a further unintended byproduct.

[0003] WO 2009 / 124410 A1 therefore proposes that process gases generated in the electrolyte solution of a closed electroplating reactor be separated from the electrolyte solution and further processed so that they can be used as a byproduct. To separate the hydrogen from the process gases, WO 2009 / 124410 A1 describes the process gases being fed under slight overpressure into one or more membrane stages consisting of a hydrogen-selective, pore-free silicone layer applied to a porous support material, or a palladium layer that is highly selective and permeable to hydrogen. Byproducts such as hydrogen can then be stored and sold or used for energy recovery to improve the economic viability of the electroplating process.

[0004] The object of the present invention is to provide an improved method and a correspondingly improved plant for the production and use of hydrogen produced as process gas.

[0005] This problem is solved by a method having the features of claim 1 or by a system according to claim 10.

[0006] A method for obtaining and using hydrogen according to the present invention comprises, for example, the following steps: a) Providing a hydrogen-containing gas mixture, b) Introducing the gas mixture into a single- or multi-stage gas separation membrane rack which has at least one hollow fiber membrane or another passive membrane suitable for processing by selective permeation, which is suitable for separating a hydrogen-containing permeate from a retentate which consists of a gas mixture containing hydrogen, c) Measurement of the hydrogen content of the permeate, d1) Storage of the permeate in a tank, provided that the hydrogen content of the permeate measured in step c) reaches or exceeds a predetermined limit, or d2) Introducing the permeate into the gas separation membrane rack and repeating step c), provided that the hydrogen content of the permeate measured in step c) is below the predetermined limit, or d3) Introducing the permeate into a downstream passive or active processing system if the hydrogen content of the permeate measured in step c) does not reach the predetermined limit even after a maximum of n repetitions of step b), and subsequently repeating step c). e) Conversion of the permeate contained in the tank into electrical energy.

[0007] The gas mixture in step a) can, for example, be at least partially the process gas generated in an electroplating process. In this case, a standard industrial electroplating tank can be extended with a specially encapsulated gas collection system to capture the separated or by-product gas mixture with minimal loss and feed it into the processing system in a highly concentrated form. The reactor can be a closed container, allowing for controlled removal of the gas mixture. Additionally or alternatively, floating, air-filled plastic spheres can be used to minimize heat and evaporation losses and improve the removal of the gas mixture.

[0008] According to an independent inventive concept, the gas separation membrane rack can comprise a membrane element with a permeate collection tube, wherein hollow fiber membranes are arranged as one or more bundles around the permeate collection tube. This can be done either parallel to the longitudinal axis of the permeate collection tube or wound around the permeate collection tube, preferably helically, and particularly preferably such that the helical lines cross each other per winding layer. For example, the gas separation membrane rack can comprise one or more cartridges of the type described in EP 3 328 521 B1. The membrane element can optionally be connected to a downstream passive or active processing system and then serve as a precursor if the required purity cannot be achieved by the membrane element itself.

[0009] For further processing of the hydrogen-containing permeate, it should have the highest possible purity. In steps d1), d2), and d3), the limit value of the hydrogen content measured in step c) can, for example, be at least 95.0%, in particular at least 99.0%, and most preferably at least 99.95%. It has proven particularly advantageous if the limit value is defined such that the quality standard of Hydrogen 3.5 (i.e., a purity of 99.95%), Hydrogen 5.0 (i.e., a purity of 99.9990%), or Hydrogen 7.0 (i.e., a purity of 99.999990%) is achieved. This is particularly useful for the use of the permeate, i.e., the hydrogen, in combined heat and power plants (usually at least Hydrogen 3.5) or in fuel cells (usually at least Hydrogen 5.0).

[0010] In a further development of an independent inventive concept, the gas to be introduced into the gas separation membrane rack is compressed to a predetermined pressure before step b) and / or during step d2) and / or during step d3). In other words, the gas can be stored, for example, and compressed using compressors until the ideal process pressure for separating the hydrogen is reached.

[0011] According to a further independent inventive concept, in step e) the hydrogen-containing permeate is converted into electrical energy in a combined heat and power plant by combustion of the hydrogen or, if applicable, methanized permeate, in a fuel cell, and / or in a gas turbine. According to the invention, energy recovery from the processed permeate can be carried out in an energy form suitable for subsequent processes, taking into account maximum efficiency and its storage. Depending on the type of recovery, the limit value in step c) can be adjusted accordingly. In a preferred example, additional processing can be completely omitted, and the contaminated gas mixture can be fed directly to the recovery unit.

[0012] The energy obtained according to the invention can, for example, primarily flow into the secondary stage of an electroplating process or alternatively be made available to third parties. In particular, the electrical energy generated in step e) can be used in a process, especially an electroplating process, in which a hydrogen-containing gas mixture is produced, wherein this process provides the hydrogen-containing gas mixture according to step a). This creates a closed-loop system for the production and use of hydrogen.

[0013] If the provision of a hydrogen-containing gas mixture according to step a) is carried out by a process, in particular an electroplating process, additional energy input is often required beyond the energy obtained from the hydrogen. Preferably, electrical energy generated entirely or partially from renewable sources is used for this purpose.

[0014] According to a further independent inventive concept, if the provision of a hydrogen-containing gas mixture according to step a) is carried out by a process, in particular an electroplating process, thermal energy generated in step e) can additionally be supplied to this process. Alternatively or additionally, thermal energy generated as waste heat in this process and / or thermal energy generated in step e) can be used to generate electrical energy. This allows the process according to the invention to be operated very energy-efficiently.

[0015] According to a further independent concept, the invention relates to a plant for the production and use of hydrogen, for example by means of a process of the type described above. Such a plant according to the invention can comprise a first device, in particular an encapsulated container with varying degrees of sealing, in which a hydrogen-containing gas mixture is produced using electrical and / or thermal energy, a gas separation membrane rack, and optionally a further downstream processing stage for separating hydrogen from the gas mixture, and a second device configured to generate electrical and / or thermal energy from hydrogen. Additionally, the plant can include conduits configured to convey the hydrogen-containing gas mixture from the first device to the gas separation membrane rack.Furthermore, the first device and the second device are preferably connected in such a way that electrical and / or thermal energy generated in the second device can be supplied to the first device and used there.

[0016] The present invention relates, irrespective of the above description of preferred applications and their definition in the claims, essentially to four independent but combinable inventive concepts in connection with the production and use of hydrogen. One possible application is electroplating, but the invention is not limited to this application.

[0017] These four independent inventive ideas are explained below: 1. Energy supply

[0018] The aim of this invention is to maximize the share of secondary energy in the total demand, to maintain a stable and uninterruptible power supply (UPS), to balance fluctuations caused by renewable energies in the distribution network in a grid-friendly manner, and to increase sector coupling, including for heat, mobility, and electricity. Secondary energy, in this context, describes, for example, the maximum recovery of energy from the closed-loop system in order to minimize the primary energy supplied from external sources.

[0019] A distinction is made between electrical and thermal energy input. Electrical energy input can come from various energy sources, which can also be combined. This includes, in particular, the following options: Primary energy is supplied through external energy sources, e.g., the purchase of green energy. Optimal use of the evolution of the energy market (dynamic electricity tariffs) can be achieved with the help of intelligent consumption forecasting. For example, inexpensive green primary energy can be purchased during periods of low tariffs to be converted into hydrogen and ultimately used as secondary energy.

[0020] Maximum utilization of the secondary energy recovered from the process (recuperation) can be achieved while ensuring an uninterrupted and continuous energy supply. Feeding excess secondary energy into the public grid is possible. Alternatively or additionally, the self-produced hydrogen can be used, either from surplus energy from renewable energy sources or from the processing processes, for direct conversion into secondary energy, e.g., in a hydrogen-powered combined heat and power (CHP) plant.

[0021] Finally, it is also possible to use the self-produced hydrogen, both from excess energy from renewable electricity generators and from the processing processes for conversion into a chemical fuel (Power-to-X), i.e., for example, the production of e-fuels, e-methanol, e-methane or e-hydrogen.

[0022] Thermal energy input can also originate from various energy sources, which can also be combined. This includes, in particular, the following options: Primary energy is supplied via external energy sources, e.g., the purchase of green energy. The secondary energy recovered from the process is utilized as much as possible. Heat energy generated, for example, during electroplating processes can be made available and used via heat exchangers. Heat energy generated during conversion processes can be introduced into the heat cycle and used. Furthermore, waste heat generated during the conversion of hydrogen to Power-to-X can be utilized. Feeding excess secondary energy into the public district heating network is also possible. 2. Electroplating

[0023] The aim of this invention is to optimize existing technological processes to their efficiency limits, focusing on minimizing energy consumption. This will be achieved by leveraging existing technology and reducing energy consumption through the optimization of all resources involved in the overall process, as well as potentially through additional indirect measures.

[0024] Optimizing equipment can involve the following measures, individually or in combination: Increasing the circulation rate in the electroplating process results in better chrome plating. Standard electroplating tanks can be equipped with a specially encapsulated gas collection system to capture the separated gas mixture, a byproduct, with virtually no loss and feed it into the processing system in a highly concentrated form, thereby reducing the exposure of employees. In reactor technology, this can be achieved, for example, with an encapsulated container or a closed container with varying degrees of sealing, allowing for the controlled removal of the gas mixture. Alternatively or additionally, floating air-filled plastic spheres can reduce heat and evaporation losses and improve the removal of the gas mixture.Another measure is the flexible and optimal adjustment of the anode gap to reduce cell voltage. Optimizing the anode shape to prevent over-coating while still ensuring a uniform coating of the component also increases the efficiency of the electroplating process. Frequency-controlled pump motors for flexible process control further contribute to reducing energy costs.

[0025] In addition to these direct electroplating resources, indirect measures can also lead to the desired goal. This includes, for example, the use of IoT-enabled equipment and measurement technology to generate a digital twin. The collected measurement data can be used for intelligent process control and energy consumption management. Furthermore, predictive maintenance approaches or other AI-supported approaches can be used to increase efficiency, such as through the early detection of process malfunctions and the reduction of downtime. Smart metering enables the use of dynamic electricity tariffs to reduce energy costs and relieve the strain on the distribution network. Moreover, the use of optimized equipment offers advantages such as increased automation, smart metering technology (IoT), switched-mode power supplies, and / or cooled copper cables. 3. Processing of a hydrogen-containing gas mixture

[0026] The main objective of this inventive concept is to make the hydrogen-containing gas mixture obtained, for example, in electroplating, which is generated there as a waste product, available for use in downstream systems in the required purity, concentration and (partial) pressure by means of suitable processing processes.

[0027] The basic idea behind this aspect of the invention is that hydrogen is produced in many industrial processes, but often as a mixture with other gases that can only be purified with considerable energy expenditure. Purification processes are complex, expensive, and frequently do not achieve the desired purity of the hydrogen. For example, even a small amount of carbon monoxide can inhibit further process steps. It "poisons," or rather inactivates, many catalysts containing precious metals. Therefore, costly purification processes are required to isolate the hydrogen before storage. In the case of electroplating, hydrogen is contaminated with chromium(VI) compounds, for example, during chrome plating. Similarly, other impurities can arise during other electroplating surface treatments. For further processing of the hydrogen-containing gas mixture, e.g., in a fuel cell, at least the Hydrogen 3 quality standard is usually required.A purity level of 5 must be achieved, which corresponds to 99.95%. Therefore, the hydrogen separation process must be of a correspondingly high quality.

[0028] The processing can be carried out, among other things, by the following technologies: membrane technology including the use of a hollow fiber membrane and / or a foil membrane, e.g. palladium membranes, by classic wet chemical processes, by PSA - Pressure Swing Adsorption (PEM pressure swing adsorption), by PEM / processes with silicon oxide desiccant, by boron organometallic compounds, by chemical storage and / or by a Sabatier process.

[0029] It is essential to note that hydrogen is produced as a mixture with other gases in many industrial applications. The present invention can therefore be extended to individual applications and is thus universally applicable without being limited to the example of electroplating. 4. Conversion of hydrogen into a suitable form of energy

[0030] The aim of this invention is to generate energy from hydrogen-containing gas, processed as described above, into an energy form suitable for subsequent processes, taking into account maximum efficiency and its storage. The energy obtained is intended primarily to flow into the secondary stage, for example, of an electroplating process, thus covering the base load of the generator, or alternatively to be made available to third parties. According to the invention, electrical energy from renewable sources can also be used directly or indirectly, either additionally or alternatively.

[0031] Direct use of electrical energy occurs, for example, through the use of self-generated (green) electricity in the electroplating process, by covering the company's own electricity needs (peripheral systems), and / or by feeding surplus energy into the public grid. Indirect use of electrical energy can be achieved by converting it into hydrogen through electrolysis, such as PEM electrolysis or alkaline membrane electrolysis, by storing hydrogen, and / or by electrifying hydrogen. The latter can be done, for example, in a combined heat and power (CHP) plant that uses pure hydrogen or biogas after methanization of the hydrogen, for example, through honeycomb methanization or three-phase methanization. Electrification of hydrogen is also possible using a fuel cell or in a so-called HyFlex-Power gas turbine, which can use either 0 to 100% hydrogen or 0 to 100% natural gas to generate electricity and heat.

[0032] The hydrogen obtained from the processing can be indirectly electrified with the hydrogen obtained from secondary electrical energy, fed directly into the emerging hydrogen distribution network or used in other ways.

[0033] The thermal energy or waste heat from the above-mentioned conversions or the electroplating process can be used internally via heat exchangers, fed into the district heating network, or used for other purposes.

[0034] The invention is explained in more detail below with reference to an exemplary embodiment and the accompanying drawing. The drawing schematically shows: Fig. 1 a block diagram of the material and energy flows in a plant according to an embodiment of the present invention and Fig. 2 a block diagram for the processing of hydrogen according to an embodiment of the present invention.

[0035] In Fig. Figure 1 illustrates an exemplary system or process according to the present invention, demonstrating how hydrogen-containing gases generated in a process, for example, electroplating, can be efficiently utilized. Primary energy is supplied to the electroplating process for its operation. During electroplating, a hydrogen-containing gas mixture is produced, for example, contaminated with chromium (VI), which is collected or extracted and subjected to purification. The hydrogen produced, purified to the required level of purity, can be temporarily stored in a tank. The hydrogen can then be converted into electrical energy, which is supplied to the electroplating process as secondary energy and can at least partially replace the primary energy there.The heat generated during electroplating and / or during the conversion of hydrogen into electrical energy can also be used, for example to generate electrical energy and / or supplied to the electroplating process as thermal energy.

[0036] The use of primary energy can be further reduced by using electrical energy from renewable energy sources either directly as secondary energy, or by first using it through electrolysis to produce hydrogen, which is then converted into electrical and thermal energy together with the processed hydrogen from electroplating as described above and fed back into the process as secondary energy.

[0037] The processing of hydrogen-containing gases is in Fig. 2 shown in detail. Fig.S01, S02, S03, and S04 designate measuring points with sensors for measuring hydrogen purity. A01 designates an extraction system. MV01, MV02, MV03, MV04, and MV05 designate controllable valves, such as solenoid valves, while DRV01 and DR02 are pressure regulating valves, and RV01 is a check valve. Compressors are designated KK01 and KK02, respectively. V01 and V03 designate tanks for hydrogen storage, and V02 designates a rack with at least one gas separation membrane. The gas separation membrane rack V02 can contain individual filter modules that can be connected in series or parallel, depending on the application, and can also be replaced. P01, P02, and P03 are pressure gauges for displaying the pressures.

[0038] The hydrogen mixture is extracted via a suction device A01, for example from the electroplating process, compressed in a compressor KK01, and temporarily stored in a tank V01 until a suitable pressure is reached. Once the ideal process pressure for hydrogen separation is achieved, the solenoid valve MV01 opens, and the gas mixture (feed) flows through the gas separation membrane rack V02 at a defined flow rate. At the rack's outlet, the purity of the permeate (hydrogen mixture) is checked using hydrogen purity measurement technology S03. The separated gas (retentate) is discharged in a separate process line and properly disposed of.

[0039] If the desired purity is not achieved at measuring system S03, solenoid valve MV02 opens, solenoid valve MV05 remains closed, and the gas mixture is recompressed by compressor KK02 to the appropriate operating pressure. This process is carried out n cycles until measuring system S03 measures the desired hydrogen quality at the outlet of the purification circuit. If the desired hydrogen quality is not achieved after n cycles, the gas mixture can be introduced into a downstream passive or active processing system by opening solenoid valves MV03 and MV04. This process continues until measuring system S03 measures the desired hydrogen quality at the outlet of the gas separation membrane rack.

[0040] A predefined limit value is, for example, a hydrogen purity of 99.95% or 99.999990%. As soon as the desired hydrogen quality is reached, the solenoid valve MV05 opens and valve MV02 closes, so that the processed hydrogen can be stored in the tank (V03) and used as needed.

[0041] The foregoing description refers by way of example to an electroplating process and the processing and use of hydrogen. However, the invention is not limited to these examples. Rather, the invention encompasses all processes in which gases or gas mixtures are produced that can be stored and, if necessary, converted into electrical and / or thermal energy after processing. This also includes processes in which other gases, other than hydrogen, are produced that can be used in a correspondingly usable way.

Claims

A method for the production and utilization of hydrogen comprising at least the following steps: a) providing a hydrogen-containing gas mixture; b) introducing the gas mixture into a single- or multi-stage gas separation membrane rack comprising at least one hollow fiber membrane or another passive membrane suitable for processing by selective permeation, capable of separating a hydrogen-containing permeate, consisting of a gas mixture containing hydrogen, from a retentate; c) measuring the hydrogen content of the permeate; d1) storing the permeate in a tank if the hydrogen content of the permeate measured in step c) reaches or exceeds a predetermined limit; or d2) introducing the permeate into the gas separation membrane rack and repeating step c) if the hydrogen content of the permeate measured in step c) falls below the predetermined limit.or d3) Introducing the permeate into a downstream passive or active processing system if the hydrogen content of the permeate measured in step c) does not reach the predetermined limit even after a maximum of n repetitions of step b), and subsequently repeating step c), e) Conversion of the hydrogen-containing permeate from the tank into electrical energy. Method according to claim 1, characterized in that the gas mixture in step a) is at least partially the process gas produced in an electroplating process. Method according to claim 1 or 2, characterized in that in step b) the gas separation membrane rack has a membrane element with a permeate collecting tube, wherein hollow fiber membranes are arranged as one or more bundles around the permeate collecting tube, either parallel to the longitudinal axis of the permeate collecting tube or wound around the permeate collecting tube, preferably helically, particularly preferably such that the helical lines cross each other per winding layer. Method according to one of claims 1 to 3, characterized in that in step d) the limit value of the hydrogen content measured in step c) is at least 95.0%, in particular at least 99.0%, and especially preferably at least 99.95%. Method according to one of claims 1 to 4, characterized in that before step b) and / or during step d2) the gas to be introduced into the gas separation membrane rack is compressed to a predetermined pressure. Method according to one of claims 1 to 5, characterized in that in step e) the conversion of the hydrogen-containing permeate into electrical energy takes place in a combined heat and power plant by combustion of the optionally methanized permeate, in a fuel cell and / or in a gas turbine. Method according to one of claims 1 to 6, characterized in that the electrical energy generated in step e) is used in a process, in particular in an electroplating process, in which a hydrogen-containing gas mixture is produced, wherein this process provides the hydrogen-containing gas mixture according to step a). Method according to one of claims 1 to 7, characterized in that the provision of a hydrogen-containing gas mixture according to step a) is carried out by a process, in particular an electroplating process, to which additionally regeneratively generated electrical energy is supplied. Method according to one of claims 1 to 8, characterized in that the provision of a hydrogen-containing gas mixture according to step a) is carried out by a process, in particular an electroplating process, to which thermal energy generated in step e) is additionally supplied, and / or that thermal energy generated as waste heat in this process and / or thermal energy generated in step e) is used to generate electrical energy. Plant for the production and utilization of hydrogen by means of a method according to one of the preceding claims, wherein the plant comprises a first device, in particular an encapsulated container with different degrees of sealing, in which a hydrogen-containing gas mixture is produced using electrical and / or thermal energy, a gas separation membrane rack for separating a hydrogen-containing permeate from the gas mixture, and a second device configured for generating electrical and / or thermal energy from hydrogen, wherein the plant further comprises conduits configured to convey the hydrogen-containing gas mixture from the first device to the gas separation membrane rack, and wherein the first device and the second device are connected to each other in such a manner as tothat electrical and / or thermal energy generated in the second device can be supplied to the first device; characterized in that the system further comprises a device for measuring the hydrogen content of the permeate and is configured to: • store the permeate in a tank if the hydrogen content of the permeate measured in the device for measuring the hydrogen content reaches or exceeds a predetermined limit; or • reintroduce the permeate into the gas separation membrane rack if the hydrogen content of the permeate measured in the device for measuring the hydrogen content falls below the predetermined limit; or • introduce the permeate into a downstream passive or active processing system if the hydrogen content of the permeate measured in the device for measuring the hydrogen content does not reach the predetermined limit even after a maximum of n repetitions.

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