Spiral electrolysis module for converting carbon dioxide, and method for producing same

Abstract

The invention relates to an electrolysis cell, in particular for converting CO2 by means of electrolysis, comprising at least one assembly (2) having at least one anode chamber with at least one feed line (41) connected thereto for an anolyte, at least one cathode chamber having at least one feed line (51) connected thereto for a catholyte, and optionally at least one gas chamber which adjoins the cathode chamber and is connected thereto and which has at least one feed line, via which a gas such as CO2 can be fed into the cathode chamber (5) and / or gas chamber (6), and discharge lines. According to the invention, the at least one assembly (2) is provided in a spiral shape. The invention further relates to a method for converting a gas such as CO2 by means of electrolysis and to a method for producing an electrolysis cell.

Description

[0001] Spiral electrolysis module for converting carbon dioxide and method for producing the same

[0002] The invention relates to an electrolysis cell, in particular for converting CO2 by electrolysis, comprising at least one assembly with at least one anode chamber with at least one supply line for an anolyte connected thereto, at least one cathode chamber with at least one supply line for a catholyte connected thereto and optionally at least one gas chamber adjoining and connected to the cathode chamber with at least one supply line via which a gas such as CO2 can be fed into the cathode chamber and / or gas chamber.

[0003] Furthermore, the invention relates to a method for converting a gas such as CO2 by electrolysis, in particular with an electrolysis cell of the type mentioned above, wherein the gas such as CO2 is fed into and reduced in a cathode chamber or a gas chamber connected to such a cathode chamber.

[0004] Furthermore, the invention relates to a method for producing an electrolysis cell for converting a gas such as CO2 by electrolysis, in particular an electrolysis cell of the type mentioned above, wherein at least one assembly is formed with at least one anode chamber with at least one supply line for an anolyte connected thereto, at least one cathode chamber with at least one supply line for a catholyte connected thereto and optionally at least one gas chamber adjoining and connected to the cathode chamber with at least one supply line via which the gas such as CO2 can be fed into the cathode chamber and / or gas chamber, as well as outlet lines.

[0005] The increasing emission of carbon dioxide (CO2) into the atmosphere in recent decades is considered one of the main causes of global warming. As with other climate-relevant gases, efforts are being made to find solutions to this problem. A first approach is to reduce CO2 emissions. However, this is hardly feasible in the short term, especially at the international level. Furthermore, individual industrial sectors cannot easily be converted to CO2-free production or at least to production with reduced CO2 emissions. Therefore, a second approach is to keep the resulting CO2 emissions low by converting the carbon dioxide at the site of production into substances that are not harmful to the climate and can be advantageously reused in other reactions.Since reducing CO2 emissions may not be sufficient to stop global warming, this second approach is of great importance.

[0006] Among the various options for directly utilizing CO2 at the point of its production, the electrochemical reduction of CO2 to form fuels represents a particularly interesting possibility. State-of-the-art research has been underway for decades to convert CO2 into compounds such as methane, methanol, and / or ethanol in a so-called "dream reaction." If this could be achieved in an energy-efficient and environmentally friendly way, climate-damaging CO2 could be converted into usable substances, making it a truly perfect reaction for the environment. CO2 emissions from industry, such as flue gas, exhaust gases from heating systems, exhaust gases from biotechnology plants, and the like, could be utilized to produce useful products that could either be further processed or, if necessary, temporarily stored.

[0007] Although the conversion of CO2 as described above offers many advantages and has therefore been researched for decades, no decisive breakthrough has yet been achieved in the electrochemical conversion of CO2. Such an electrochemical conversion requires an electrolysis cell that allows the corresponding reaction to be carried out efficiently on a large-scale. While individual successes on a laboratory scale using an electrolysis cell of the type mentioned above can confirm theoretical approaches, they do not allow for efficient implementation on a larger scale.

[0008] The applicant's Austrian patent application AT525988 A4 describes an electrolysis cell formed from a stack of a repeating sequence of anode compartment, cathode compartment, and gas compartment, which adjoins the cathode compartment. The stack can, for example, comprise 20 such sequences. According to the aforementioned patent application, the individual layers of the stack, as well as a current supply, are arranged in such a way that only a single supply line for an anolyte and a supply line for the catholyte and / or a supply line for the gas compartments, as well as corresponding drain lines and two power connections, are required. The layers are arranged one on top of the other in the form of round sub-elements and form a cylinder. The corresponding system is extremely powerful because a large number of anode compartments, cathode compartments, and optional gas compartments are arranged in parallel and can be supplied with a medium simultaneously.

[0009] The object of the invention is to develop an electrolysis cell of the type mentioned above in such a way that it enables the highest possible gas conversion, in particular CO2 conversion, per unit of time.

[0010] A further aim of the invention is to further develop a method of the type mentioned at the outset for converting a gas, in particular CO2, by electrolysis in such a way that the highest possible conversion rate for the gas is achieved.

[0011] Finally, it is a further object of the invention to provide a method for producing an electrolysis cell of the type mentioned at the outset, with which a particularly efficient electrolysis cell can be produced.

[0012] The object of the invention is achieved if, in an electrolysis cell of the type mentioned at the beginning, at least one assembly is arranged in a spiral shape.

[0013] During the course of research, it was discovered that the spiral arrangement of at least one component offers several advantages: First, it provides a cost-effective design, as the spiral arrangement is compact and space-saving. If multiple electrolysis cells are provided, this effect is multiplied. Another advantage is that, due to the alternating layers of anode and cathode compartments, including membranes and possibly gas compartments, on the one hand, and the spiral arrangement, on the other, the layers meet virtually twice in a repeating arrangement, thus providing a larger contact area.

[0014] This leads to improved conversion efficiency. The alternating layers of electrodes and membranes in the spiral module promote improved distribution of reactants and products. Furthermore, a corresponding electrolysis cell is relatively simple in construction, as it requires few components and their required connections.

[0015] The electrolysis cell can be designed in several ways. In a particularly simple and therefore preferred variant, the spiral arrangement is formed by a single rolled-up assembly comprising the anode chamber and the cathode chamber, as well as, if applicable, the optional gas chamber. The corresponding chambers can be provided by suitably designed layers, which are rolled up together with the required supply and discharge lines. The individual chambers themselves comprise additional components and are, in particular, enclosed by membranes, so that when rolled up or wound up, the situation arises that double contact surfaces are created for each chamber.

[0016] If the gas to be converted is CO2, this not only results in a simple structure but also in the creation of an electrolysis cell with very high CO2 conversion efficiency. As with the variants explained below, it is advantageous if the gas space is mandatory. In particular, a gas diffusion electrode can be present. While it is also possible to introduce CO2 into a cathode space, the performance of the electrolysis cell is then also determined by the solubility of CO2 in the catholyte. If, on the other hand, a gas space is provided, into which CO2 can be introduced and come into contact with the catholyte via a porous connecting area provided with a catalyst, the performance of the electrolysis cell is significantly higher, since the solubility of CO2 in the catholyte plays a subordinate role.In addition to the conversion of CO2, the device according to the invention can also be used for other applications, for example for electrosynthesis or for the conversion of other gases.

[0017] If a gas diffusion electrode is provided, the gas diffusion layer advantageously has a thickness of less than 500 pm, preferably 100 pm to 300 pm. The gas diffusion electrode can have a porosity of 50% to 90%, in particular 60% to 80%. Nanoparticles of silver and copper (Ag-Cu nanoparticles), for example, are used as catalysts. The gas space is formed by a conductive material so that a current flow through the gas space is possible. A structured layer made of a conductive material can be used for this purpose. This allows, on the one hand, a gas flow to be controlled in relation to a direction, and on the other hand, a current flow can occur via contact surfaces between the structured layer and the catholyte space or the catholyte spaces adjacent to both sides. The structured layer, in interaction with the other layers, is advantageously designed so that the electrolysis cell can be operated at a pressure of up to 10 bar.

[0018] As an alternative to a variant with just a single anode chamber and a single cathode chamber and optionally a single gas chamber, which form a single assembly, it can also be provided that the spiral arrangement is formed by several curved assemblies, each comprising an anode chamber and a cathode chamber and optionally an optional gas chamber, wherein the assemblies are offset from one another and arranged adjacent to one another. This also results in the advantages described above, but the individual assemblies have to be manufactured separately and their position must be adjusted so that the supply lines for the individual chambers can be suitably attached. In this variant, separate supply lines and discharge lines are also provided for each individual assembly, which has the advantage of individual power supply to each assemblies.

[0019] The assembly or assemblies are preferably arranged to form a cylinder. If a single assembly is provided, the assembly is wound spirally around a cylinder's longitudinal axis. Similarly, if there are multiple assemblies, the individual assemblies extend around the cylinder's longitudinal axis so that, in the corresponding spiral arrangement, as with a single assembly, the available space is used effectively. In both cases, a center of the cylinder can remain free along the cylinder axis. With just one assembly, this may be necessary to avoid excessive mechanical stress on the assembly by winding in the center. This also applies to multiple assemblies. In this case, a free center of the cylinder may be necessary, in particular for multiple supply lines or discharge lines.In both cases, the supply lines and the outlet lines can be arranged on the outside of the cylinder or in the free center of the cylinder. This arrangement allows for simple feeding into the available spaces and also a space-saving design of the electrolysis cell. The assembly or assemblies are preferably made up of layers. The supply lines are designed to feed the layers from the sides. The same applies to the outlet lines. Lateral also includes feeding the layers from the front and / or the base. Preferably, feeding is done on one of the broad sides of the layers. An outlet line can also be provided on the broad side of the layers. This allows for simple manufacture of the electrolysis cells because the supply lines and the outlet lines can be connected to the layers in a spiral before the layers are wound.The supply lines can be located on the outside of the spiral winding and the drain lines on the inside; a reverse arrangement is also possible. In this context, it is particularly preferred to provide a power connection on the supply line for the anolyte and a power connection on the supply line for the catholyte. This allows for a simple current flow to be established, and no complex structural precautions are required to enable current flow.

[0020] Particularly advantageously, the at least one anode chamber and / or the at least one cathode chamber is formed with a sheet metal having channels, wherein the channels are configured to conduct the anolyte or the catholyte. A corresponding sheet metal can be manufactured relatively easily, for example by embossing, deep drawing, or other manufacturing processes. With appropriate sheets, in particular, a flow direction for the anolyte and the catholyte can be specified. This makes it possible to allow the media, separated from one another by a membrane or other chamber separation layer, to flow either in the same direction or in opposite directions, or even perpendicular to one another. Ultimately, any desired flow directions for the anolyte on the one hand and the catholyte on the other hand can be set in the cylinder. This allows, for example, a CC>2 conversion to be further optimized.

[0021] In this context, it can also be provided, in particular, that an expanded metal mesh is provided in the at least one anode chamber and / or the at least one cathode chamber adjacent to the sheet metal. The expanded metal mesh enables a uniform supply of the medium to the corresponding reaction surface and also a uniform distribution of the forces on the separating layers, in particular membranes. Accordingly, the expanded metal mesh advantageously bridges a distance to a chamber separating layer, such as a membrane, which adjoins the next chamber.

[0022] Particularly preferably, the supply line for the anolyte and / or the supply line for the catholyte is or are tubular with lateral openings. The supply lines are usually made of a conductive material such as copper or steel for the current conduction. Following the layers of the electrolysis cell, the tubular supply lines have openings so that the anolyte and the catholyte can be fed into the anode compartment and the cathode compartment. For this purpose, the openings extend through a side wall of the tubular supply lines. As a rule, the cathode compartment and / or the anode compartment are connected to the associated supply line via a distribution compartment. The distribution compartment can be formed by a layer which adjoins the openings of the supply line and via which openings in the cathode compartment or anode compartment are fed.It is advantageous if the lateral openings are located along a broad side of the layers, especially if they are in fluid contact with them. The channels of the cathode and / or anode chambers can then be fed vertically, especially if the channels run along a long side of a layer.

[0023] It can also be provided that the at least one gas space is formed with channels which preferably run along a longitudinal side of a layer.

[0024] It can also be provided that the at least one cathode chamber is formed with a sheet metal having channels, wherein the channels are configured to conduct the anolyte or the catholyte, and wherein the at least one gas chamber is formed with channels which are connected to channels of the cathode chamber for electrolysis. When wound into a spiral, the gas chamber can be in fluid contact with a cathode chamber on both sides. Although the construction of both the cathode chamber and the gas chamber with channels somewhat reduces the reaction conversion because reaction surface must be sacrificed for the structuring of the channels, in return a more stable structure is achieved overall, which allows the use of higher pressures with regard to the use of the electrolysis cell. The cathode chamber and the gas chamber are advantageously designed in the form of a gas diffusion electrode.

[0025] In all design variants, a housing can advantageously be provided on the outside, preferably pressed onto the assembly or assemblies. This keeps the assemblies stable and in shape.

[0026] Furthermore, suitable seals are provided on the outside of the layers. The seals are provided together with the layers and formed into their final shape. The spiral arrangement can also be tensioned, ensuring that the seals, in particular, are particularly tight and thus permanently sealed.

[0027] In a further aspect, the invention relates to a system with an electrolysis cell according to the invention. CO2 not converted in the electrolysis cell is separated in the system and fed back into the electrolysis cell for conversion.

[0028] The further objective is achieved if, in a process of the type mentioned at the outset for converting a gas such as CO2 by electrolysis, the gas such as CO2 is fed into a spiral arrangement having at least one anode chamber and at least one cathode chamber and optionally at least one gas chamber.

[0029] A particularly advantageous feature of a process according to the invention is that the exchange surfaces or interfaces between individual compartments, such as the anode compartment on the one hand and the cathode compartment on the other, and possibly also the cathode compartment and the gas compartment, are maximized, which is achieved by the spiral arrangement of the corresponding compartments. This leads to a particularly efficient process.

[0030] The method according to the invention is used in particular for the conversion of CO2, but can also be used for other applications such as electrosynthesis or for the conversion of other gases. An electrolysis cell according to the invention can be used for this purpose. The electrolysis cell can be operated in a temperature range from 15° to 80°C. It can be provided that an anolyte in an anode compartment and / or a catholyte in a cathode compartment is passed through a metal sheet with channels, wherein the flow direction within the anode compartment or the cathode compartment is determined by the channels. It is preferably provided that the anolyte and / or catholyte is allowed to flow via an expanded metal sheet to a chamber separation layer such as a membrane. The flow direction of the corresponding fluids can be controlled via a provided metal sheet.By subsequently distributing the air flow through an expanded metal mesh, a uniform flow can be achieved, particularly for a membrane. Another advantage is that the membrane is also subjected to uniform forces in this way.

[0031] In one variant, the anode and cathode chambers are constructed in layers, and the anolyte and catholyte are fed laterally into the respective layers. This allows for easy introduction of the fluids into the designated spaces. The lateral feed can be achieved, in particular, along one of the broad sides.

[0032] Electrolysis can produce gaseous products such as CO and ethylene, as well as liquid products. The Faradaic efficiency can be up to 99% for CO and about 50% for ethylene.

[0033] The further objective of the invention is achieved if, in a method for producing an electrolysis cell for converting a gas such as CO2 of the type mentioned above, the anode chamber and the cathode chamber, as well as optional components forming the gas chamber, are provided as layers and arranged spirally, in particular wound. In particular, an electrolysis cell according to the invention can be produced.

[0034] Using such a process, a highly efficient electrolysis cell for converting, in particular, CO2 can be produced in a particularly simple manner. Spiral winding can preferably be carried out by providing only the respective layers for a single anode compartment, a single cathode compartment, and optionally a single gas compartment, and then spirally winding them. An alternative is to provide several shorter units and arrange them in a spiral by placing them next to one another. The individual components then have different radii in the bent state, depending on where they are positioned in the electrolysis cell.

[0035] It is advantageous if the layers are provided with supply and discharge lines at the same time. In addition to the supply lines, the required discharge lines can also be provided at the same time. The supply and discharge lines are connected to the respective layers and can be processed together with them into a spiral arrangement. The layers can also be arranged or wound with external seals.

[0036] The individual layers can be formed, at least partially, with metal sheets with channels, expanded metal mesh, and membranes. The formation of channels allows for targeted control of the flow. The arrangement of expanded metal mesh, especially between a metal sheet and a membrane, offers advantages in terms of ensuring a uniform flow to the adjacent membrane.

[0037] It is particularly advantageous if the layers are formed into a cylinder and encased on the outside with a housing. This housing provides additional stability and security against unwanted fluid leakage. Furthermore, the housing can be arranged so that the layers exert pressure on the cylinder on the outside, which promotes the tightness of the electrolysis cell. In particular, the housing can be pressed on.

[0038] In a further aspect, the invention relates to a plant with a corresponding electrolysis cell for converting a gas, in particular CO2.

[0039] Further features, advantages, and effects will become apparent from the following exemplary embodiments. The drawings, to which reference is made, show:

[0040] Fig. 1 is a schematic representation of an electrolysis cell with a housing;

[0041] Fig. 2 shows a first variant of a spiral winding of an electrolysis cell;

[0042] Fig. 3 shows a second variant of a spiral winding of an electrolysis cell; Fig. 4 shows a schematic representation of the internal structure of an electrolysis cell according to Fig. 2;

[0043] Fig. 5a shows an enlarged section of Fig. 4;

[0044] Fig. 5b to Fig. 5d show various possibilities for introducing fluid in detail; Fig. 6 shows various possibilities for fluid guidance in an electrolysis cell according to Fig. 2 or Fig. 3;

[0045] Fig. 7 shows a schematic section through an electrolysis cell with an arrangement of chambers and a power supply;

[0046] Fig. 8 is a section along the line VIII-VIII in Fig. 9;

[0047] Fig. 9 is a plan view of an electrolytic cell;

[0048] Fig. 10 another electrolysis cell;

[0049] Fig. 11 a section through the electrolysis cell according to Fig. 1

[0050] Fig. 12 is a schematic representation of a section of an electrolysis cell; Fig. 13 shows the situation in Fig. 12 with fluids;

[0051] Fig. 14 is a schematic representation of a section of an electrolysis cell; Fig. 15 shows the situation in Fig. 14 with fluids;

[0052] Fig. 16 a plant with an electrolysis cell according to the invention for converting CO2.

[0053] Fig. 1 shows an electrolysis cell 1 which comprises a cylinder 3. On the outside, supply lines 41, 51, 61 and outlet lines 42, 52, 62 are schematically indicated. These lines can, for example, enter or exit the cylinder 3 via a cover, as shown. It is also possible for the lines to be introduced and / or exited via the casing of the cylinder 3 itself. The cylinder 3, together with the cover, forms a housing 13 which surrounds the active part of the electrolysis cell 1, which is designed for the conversion of CO2. This means that CO2 is electrolytically converted into products such as formic acid, methanol or the like. If there are several conversion products, these can be separated subsequently, if necessary.In addition to converting CO2, the electrolysis cell 1 can also be used to convert other reactants, for example to produce synthesis gas, carbon monoxide or ethylene. The active part of the electrolysis cell 1 is arranged inside the cylinder 3. In a particularly preferred embodiment, this is designed, for example, as shown highly schematically in Fig. 2. In this variant, the interior of the electrolysis cell 1 consists of an assembly 2, which is formed from an anode chamber 4 and a cathode chamber 5 and a gas chamber 6 connected to the cathode chamber 5, which is supplied by lines (not visible) running laterally through the casing of the cylinder 3. The corresponding chambers are present as layers 7. The layers 7 are placed on top of one another to create a spiral arrangement in the electrolysis cell 1 and then rolled up.Seals 12 can also be inserted and wound up at the same time. The individual layers 7 are designed as rectangular layers 7 with a long side and a wide side, wherein the layers 7 are wound up with the seals 12 to form the spiral arrangement. Supply lines 41, 51, 61 and discharge lines 42, 52, 62 can also be arranged at the same time. The individual lines can also serve as an aid in the winding process by holding one of the lines and winding the rest around this held line. In the center of the wound layers 7 there is a free space in which some of the lines can be guided, as can be seen. The supply lines 41, 51 can be arranged on the outside, the discharge lines 42, 52 in the free space.

[0054] Fig. 3 shows an alternative arrangement to a spiral electrolysis cell 1, wherein the spiral arrangement in this case is produced by several assemblies 2 and there are only two chambers. Similar to the variant according to Fig. 2, a wound structure results, but in this case the structure consists of a large number of assemblies 2, each of which is bent with a predetermined radius of curvature and then arranged adjacent to one another. In this case, separate supply lines 41, 51, 61 and discharge lines 42, 52, 62 are required for each individual layer 7 of an assembly 2, whereby the structure is less compact than that according to Fig. 2. Nevertheless, a relatively space-saving design can also be achieved in this case by providing some of the lines centrally in the cylinder 3. Otherwise, the corresponding space remains largely free, as shown in Fig. 2.The advantage of this variant is that each assembly 2 can be supplied with fluids (anolyte, catholyte, gas) separately. This enables a high degree of flexibility of the electrolysis cell 1 with regard to specific operating parameters. In Fig. 4 and in particular Fig. 5a, the structure of a layer 7 is shown in more detail by means of a partial section. The layers 7, which in a configuration according to Fig. 2 form the single anode chamber 4, the single cathode chamber 5 and the single gas chamber 6, can be formed with sheets 8 in relation to the anode chamber 4 and cathode chamber 5, which, as can be seen, form channels 9 into which the anolyte or the catholyte can be conducted. The orientation of the channels 9 relative to an axis of the cylinder 3 ultimately determines the direction of the fluid moving in the layer 7. Different flow directions are possible with respect to a membrane as a separating layer between the anode chamber 4 and the cathode chamber 5.This is shown in Fig. 6. The solid arrows correspond to one medium, the dashed arrows to another medium located behind the separating membrane 11 or gas diffusion electrode (GDE 11a). The fluids can be guided in the same direction, in opposite directions, or perpendicular to each other. The guidance of the fluids can be adjusted in particular so that the conversion rate of CO2 to subsequent products such as formic acid is maximized. For a corresponding fluid feed, as well as for a fluid removal, designs according to Fig. 5b to Fig. 5d can be used, for example. Fig. 5b shows a feed via a supply line 41 designed as a tube with bores or lateral openings 20, via which a fluid (anolyte or catholyte) can be fed to a flow guide plate of a layer 7 (partially exposed in Fig. 5b for visibility). A discharge via another tube can be designed analogously.According to Fig. 5b, the medium supply and removal occur at the side of cylinder 3. Fig. 5c shows a configuration in which distribution and subsequent collection take place in front-end prechambers, with fluid supply and removal occurring parallel to the flow axis in the flow guide vanes. This can occur in a similar manner with lateral flow, as shown by way of example in Fig. 5d.

[0055] Fig. 7 shows in more detail the possible structure of layers 7 for the anode chamber 4, the cathode chamber 5 and the gas chamber 6. This is a section perpendicular to a cylinder arc or parallel to the longitudinal axis of the cylinder 3; in the further section (only a central part is shown), the design shown in Fig. 7 extends repeatedly to the left and right and would initially be connected to gas chambers 6 on the outside. The anode chamber 4 and the cathode chamber 5 (design according to variant Fig. 2) can each be formed with a metal sheet 8 in the center, which, as explained, determines the flow direction of the respective fluid. An expanded metal sheet 10 is provided towards the membrane 11 or GDE 11a. This expanded metal sheet 10 bridges the space between the metal sheet 8 with the channels 9 and the adjacent membrane 11 or GDE 11a.The expanded metal mesh 10 is designed to create turbulence and thus ensure the most uniform flow possible to the adjacent membrane 11 or GDE 11a. This avoids isolated force peaks. Even more importantly, the uniform flow creates optimal initial conditions for the most complete conversion of CO2. At the same time, current can also be applied or conducted via the sheet 8. The gas space 6 requires no special measures in this regard and can, for example, be formed via a GDE 11a. Both the sheet 8 with the channels 9 and the expanded metal mesh 10 are easy to form, so that the formation of the electrolysis cell 1 with a single layer 7 or a single assembly 2 is readily possible, even if the bending radius is particularly small, particularly at the beginning of a winding process.In a 2-chamber system (so-called zero-gap cell or “membrane electrode assembly”, MEA for short), gas chamber 6 can be omitted.

[0056] To produce an electrolysis cell 1 with the structure shown in Fig. 7, the corresponding layers 7 are prepared and placed on top of one another. If necessary, external seals 12, as also indicated in Fig. 7, are also inserted for current insulation. Furthermore, a media seal is also arranged to seal the chambers. By rolling the layers 7 into a spiral, the core of the electrolysis cell 1 is formed. The seals 12 are also rolled up and thus pressed in, which ensures an excellent sealing effect during operation of the electrolysis cell 1. A cylinder s can then be pressed on and connected to a top cover. Inlet lines 41, 51, 61 and outlet lines 42, 52, 62 are positioned laterally at the appropriate location during this process and rolled up along with the layers.If the layers 7 are rectangular to form a cylinder 3, the supply lines 41, 51, 61 and the discharge lines 42, 52, 62 can be attached laterally to the broad side of the respective layer 7. In the final state, these lines thus run parallel to a longitudinal axis of the cylinder 3. All lines can be led outward via the cover attached to the cylinder 3. The electrolysis cell 1 is thus completely sealed and enclosed and can be supplied with fluids for use.

[0057] Fig. 8 shows a further embodiment of an electrolysis cell 1. The electrolysis cell 1 is shown in Fig. 9. The illustration in Fig. 8 corresponds to a section along the line VI II - VI II in Fig. 9. As can be seen in Fig. 8, the electrolysis cell 1 is basically cylindrical. The electrolysis cell 1 is designed to convert CO2 into a product gas. In principle, however, the electrolysis cell 1 can also be used for other electrolysis processes. The electrolysis cell 1 has the layered or spiral structure explained above and, in the embodiment shown in Fig. 8 and Fig. 9, is constructed as a 3-chamber system. CO2 is fed in from the side, as is an anolyte. Catholyte is also fed in from the side and is also discharged from the side at the top.The anolyte is discharged from the bottom of the electrolysis cell 1 after being introduced laterally through the jacket of the cylinder 3, while the product gas is discharged from the top. The structure of the electrolysis cell 1 is compact and can be used, for example, in the system described below and shown in Fig. 10. The cathode inflow and outflow are constructed as shown in Fig. 5c, and the anode inflow and outflow are constructed as shown in Fig. 5d.

[0058] 9 and 10 show a further example of an electrolysis cell 1 according to the invention. The electrolysis cell 1 again has an approximately cylindrical structure. As can be seen in particular in Fig. 11, a supply line 41 for the anolyte and a supply line 51 for the catholyte are provided, each formed at the top by corresponding tubes that extend approximately vertically. Corresponding tubes are provided at the bottom, resulting in a discharge line 42 for the anolyte and a discharge line 52 for the catholyte. The layers 7 are wound in a spiral and in turn form a free space, which can be seen in Fig. 11. This free space can also be reinforced if necessary. Anolyte and catholyte are supplied via the supply lines 41, 51 and removed again at the bottom via the discharge lines 42, 52. Corresponding lines are also provided for the supply of gas and for the discharge.A current can flow via current terminals 19, each of which is clamped to one of the tubes, creating a current flow between the cathode and the anode. The GDE 11a is designed to conduct electricity. Alternatively, sealed lines can also be used to bridge the gas space.

[0059] 10 and 11 is constructed as shown by way of example in FIGS. 12 to 15. FIGS. 12 and 13 schematically show part of the electrolysis cell 1. The design according to FIGS. 12 and 13 is a schematic representation of a single winding. It can be seen that in the GDE 11a, the gas chamber 6 is arranged due to the winding so that it comes into contact with the cathode chamber 5 on both sides. The cathode chamber is formed, as explained, by a sheet metal with channels 9. Channels 21 of the gas chamber 6 are arranged opposite the channels 9 of the cathode chamber 5, so that electrolysis is possible. In the illustration according to FIG. 13, each channel 21 of the gas chamber 6 lies completely against a corresponding channel 9 of the cathode chamber 5. Fig. 14 and Fig. 15 show a similar representation for an internal structure of an electrolysis cell 1 as shown in Fig. 10 and Fig. 11. In Fig.15, the inflow and outflow for the catholyte flowing through the cathode chamber 5 are highlighted. The flow to the cathode chamber 5 occurs via the supply line 51, which extends vertically from top to bottom and is tubular. As explained, openings 9 are provided in the tube through which the catholyte chamber 5 can be supplied with catholyte. For this purpose, a distribution chamber 22 is initially provided, which receives the catholyte and through which the catholyte flows into the channels 9 of the cathode chamber 5. The spiral arrangement forces the catholyte to pass through the entire spiral before it can exit via the outlet line 52. The winding results in the aforementioned bilateral contact of the gas chamber 6 with the corresponding channels 9 of the cathode chamber 5. The anolyte chamber 4 can be supplied with a corresponding structure, but does not necessarily have to have channels 9.

[0060] Fig. 16 shows a system 14 with an electrolysis cell 1. The system 11 comprises, in addition to the electrolysis cell 1, an anolyte container 15 and a catholyte container 16 as well as a product container 17 from which, for example, methanol and / or formic acid can be withdrawn. The corresponding containers are connected to the electrolysis cell 1. In particular, suitable lines are provided which are designed to introduce anolyte into the electrolysis cell 1 and to return it therefrom. The same is provided with regard to the circulation of the catholyte. In addition, a corresponding line is provided for the gas supply, which is designed to supply carbon dioxide or, if appropriate, a gas containing carbon dioxide into the respective gas spaces 6 of the electrolysis cell 1. The gas is supplied at a pressure in the range of, for example, 1.5 bar or more. The gas can be circulated, as shown in Fig.10. This allows CO2 to be recycled so that it can be converted as efficiently as possible. Gaseous products can be collected in a container 18. For this purpose, the converted product is separated by a suitable separation device and stored, for example, in the container 18. Unconverted CO2 is returned to the cycle.

[0061] Even if the invention has been presented above by way of example for embodiments for the conversion of CO2 into a synthesis gas, an electrolysis cell 1 according to the invention can also be used for the electrolysis of other reactants and also for electrosynthesis and is not limited to a conversion of CO2.

Claims

Patent claims 1. Electrolysis cell (1), in particular for converting CO2 by electrolysis, comprising at least one assembly (2) with at least one anode chamber (4) with at least one supply line (41) for an anolyte connected thereto, at least one cathode chamber (5) with at least one supply line (51) for a catholyte connected thereto and optionally at least one gas chamber (6) adjoining and connected to the cathode chamber (5) with at least one supply line (61) via which a gas such as CO2 can be fed into the cathode chamber (5) and / or gas chamber (6), as well as outlet lines (42, 52, 62), characterized in that the at least one assembly (2) is arranged in a spiral shape.

2. Electrolysis cell (1) according to claim 1, characterized in that the spiral arrangement is formed by a single rolled-up assembly (2) comprising the anode chamber (4) and the cathode chamber (5) and optionally the optional gas chamber (6).

3. Electrolysis cell (1) according to claim 1, characterized in that the spiral arrangement is formed by a plurality of curved assemblies (2) each comprising an anode chamber (4) and a cathode chamber (5) and optionally an optional gas chamber (6), wherein the assemblies (2) are arranged offset from one another and adjacent to one another.

4. Electrolysis cell (1) according to one of claims 1 to 3, characterized in that the assembly (2) or the assemblies (2) are arranged to form a cylinder (3).

5. Electrolysis cell (1) according to one of claims 1 to 4, characterized in that the assembly (2) or the assemblies (2) are formed from layers (7).

6. Electrolysis cell (1) according to claim 5, characterized in that the supply lines (41, 51, 61) and / or discharge lines (42, 52, 62) are arranged for lateral feeding of the layers (7), in particular on a broad side of the layers (7).

7. Electrolysis cell (1) according to one of claims 1 to 6, characterized in that a power connection is provided on the supply line (41) for the anolyte and a power connection is provided on the supply line (51) for the catholyte.

8. Electrolysis cell (1) according to one of claims 1 to 7, characterized in that the at least one anode chamber (4) and / or the at least one cathode chamber (5) is formed with a sheet metal (8) with channels (9), wherein the channels (9) are designed to conduct the anolyte or the catholyte.

9. Electrolysis cell (1) according to claim 8, characterized in that an expanded metal grid (10) is provided in the at least one anode chamber (4) and / or the at least one cathode chamber (5) adjacent to the sheet metal (8).

10. Electrolysis cell (1) according to one of claims 1 to 9, characterized in that the supply line (41) for the anolyte and / or the supply line (51) for the catholyte is or are tubular with lateral openings (18).

11. Electrolysis cell (1) according to claim 10, characterized in that the lateral openings (18) are adjacent to a broad side of layers (7), in particular are in fluid contact with these.

12. Electrolysis cell (1) according to one of claims 1 to 11, characterized in that the at least one gas space (6) is formed with channels (21) which preferably run along a longitudinal side of a layer (7).

13. Electrolysis cell (1) according to one of claims 1 to 12, characterized in that the at least one cathode chamber (5) is formed with channels (9), wherein the channels (9) are arranged to conduct the anolyte or the catholyte, and wherein the at least one gas chamber (6) is formed with channels (21) which are connected to channels (9) of the cathode chamber (5) for the electrolysis.

14. Electrolysis cell (1) according to one of claims 1 to 13, characterized in that the at least one gas space (6) is in fluid contact with catholyte on both sides. the cathode chamber (5) and the gas chamber (6) are designed in the form of a gas diffusion electrode.

15. Electrolysis cell (1) according to claim 9, characterized in that the expanded metal mesh (10) bridges a distance to a chamber separation layer such as a membrane (11) which adjoins the next chamber.

16. Electrolysis cell (1) according to one of claims 1 to 15, characterized in that a housing (13) is provided on the outside, which is preferably pressed onto the assembly (2) or the assemblies (2).

17. A method for converting a gas such as CO2 by electrolysis, in particular with an electrolysis cell (1) according to one of claims 1 to 16, wherein the gas such as CO2 is fed into a cathode chamber (5) or a gas chamber (6) connected to such a cathode chamber and reduced, characterized in that the gas such as CO2 is fed into a spiral arrangement with at least one anode chamber (4) and at least one cathode chamber (5) and optionally at least one gas chamber (6).

18. The method according to claim 17, characterized in that an anolyte in an anode chamber (4) and / or a catholyte in a cathode chamber (5) is passed through a sheet (8) with channels (9), wherein a flow direction within the anode chamber (4) or the cathode chamber (5) is determined by the channels (9).

19. Method according to claim 17 or 18, characterized in that anolyte and / or catholyte is allowed to flow via an expanded metal mesh (10) to a chamber separation layer such as a membrane (11).

20. Method according to one of claims 17 to 19, characterized in that the anode chamber (4) and the cathode chamber (5) are constructed in layers and the anolyte and the catholyte are fed laterally into the respective layer (7).

21. Method for producing an electrolysis cell (1) for converting a gas such as CO2 by electrolysis, in particular an electrolysis cell (1) according to one of the Claims 1 to 16, wherein at least one assembly (2) is formed with at least one anode chamber (4) with at least one supply line (41) for an anolyte connected thereto, at least one cathode chamber (5) with at least one supply line (51) for a catholyte connected thereto and optionally at least one gas chamber (6) adjoining and connected to the cathode chamber (5) with at least one supply line (61) via which the gas such as CO2 can be fed into the cathode chamber (5) and / or gas chamber (6), characterized in that the anode chamber (4) and the cathode chamber (5) and optionally components forming the gas chamber (6) are provided as layers (7) and are arranged spirally, in particular wound up.

22. Method according to claim 21, characterized in that the layers (7) are provided with supply lines (41, 51, 61) and discharge lines (42, 52, 62).

23. Method according to claim 21 or 22, characterized in that the layers (7) are arranged or wound with seals (12) arranged on the outside.

24. Method according to one of claims 21 to 23, characterized in that the layers (7) are formed at least partially with sheets (8) with channels (9) and with expanded metal mesh (10) as well as chamber separation layers such as membranes (11).

25. Method according to one of claims 21 to 24, characterized in that the layers (7) are formed into a cylinder and are encased on the outside with a housing (13).

26. Method according to claim 25, characterized in that the housing (13) is pressed on.

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