DAC system having prefilter assembly

Abstract

The invention relates to a DAC system (10) for chemico-technically extracting carbon dioxide from the ambient air (12), characterized in that the DAC system (10) comprises a prefilter assembly (18) having a particle filter element (20) and an adsorption element (22) comprising a porous adsorption material for physically and / or chemically adsorbing one or more gaseous interfering compounds from the ambient air (12), wherein the gaseous interfering compounds are selected from the group consisting of ammonia, ozone, hydrogen sulfide, sulfur oxides, nitrogen oxides, and volatile organic compounds which have a vapor pressure of 0.01 kPa or more at 20°C.

Description

[0001] Münster, September 25, 2025

[0002] Our reference: HE1206-02WO

[0003] Official file number: New registration

[0004] Applicant: Stallion SE

[0005] Nienkamp 55-85 48147 Münster

[0006] DAC system with pre-filter arrangement

[0007] Description

[0008] The invention relates to a DAC plant for the chemical-technical production of carbon dioxide from ambient air, a process for the chemical-technical production of carbon dioxide from ambient air using such a DAC plant, and the use of a pre-filter arrangement in DAC plants to increase the service life of CO2 separation units used in a DAC plant, and corresponding pre-filter arrangements and pre-filter inserts for these pre-filter arrangements.

[0009] In many areas of technology, the last few decades have been characterized by a growing awareness of the need for more sustainable economic practices and a more careful use of finite resources. The aspect of avoiding emissions, especially greenhouse gases such as CO2, has become increasingly important. In addition to avoiding greenhouse gas emissions, alternative concepts for reducing the concentration of greenhouse gases in the atmosphere have recently come into focus. These approaches are based on capturing greenhouse gases already present in the ambient air using suitable methods and either storing them or using them as secondary raw materials in other industrial processes.This advantageously reduces the concentration of potentially harmful gases in the ambient air and also provides access to another source of important industrial raw materials.

[0010] Among greenhouse gases, carbon dioxide capture is of particular importance due to its high climate activity and its great usefulness as a raw material in many chemical processes. Corresponding carbon dioxide capture systems are known from the state of the art, and various concepts exist.

[0011] One of these methods is known in English as "Point Source Capture (PSC)." These methods aim to capture exhaust gases from industrial plants or other CC>2 sources as directly as possible at the source and extract the carbon dioxide from them. In these approaches, the carbon dioxide is advantageously present in a significantly elevated concentration. Many of these methods have been developed for gas streams that not only exhibit high pollutant concentrations but also elevated temperatures. In particular, the processing of very high volume flows is a key objective to ensure time- and cost-efficient operation.

[0012] While PSC processes offer several advantages, they are also perceived as disadvantages in other respects. This is particularly true due to the need for prior exhaust gas treatment, which often requires energy-intensive or complex systems and regularly involves very high investment costs. Furthermore, it is becoming clear that PSC processes alone will not be sufficient in the future to meet the demand for CO2 capture and related products, especially as industry strives to reduce CO2 emissions more and more.

[0013] An alternative to point source capture (PSC) systems are so-called direct air capture (DAC) systems. Unlike PSC systems, these are not located directly at a carbon dioxide source, but rather extract the carbon dioxide directly from the ambient air. DAC processes and the DAC systems used are thus employed for the chemical-technical extraction of carbon dioxide directly from the ambient air. In accordance with expert understanding, this means that DAC systems are designed to extract carbon dioxide from ambient air with a comparatively low CO2 concentration. In recent years, a key focus of development has been on creating increasingly efficient DAC systems, with a wide variety of chemical-technical concepts for carbon dioxide capture being proposed.Despite the excellent results already achievable with DAC systems, further improving their performance remains a significant challenge and a worthwhile goal. In addition to increasing the time and cost efficiency of CO2 capture, and thus reducing the cost of the extracted raw material, a key focus is on extending the lifespan of DAC systems and reducing maintenance intervals and the need for replacement parts.

[0014] The primary objective of the present invention was to eliminate or at least mitigate the disadvantages of the prior art.

[0015] In particular, the object of the present invention was to provide an advantageous DAC plant which enables the chemical-technical recovery of carbon dioxide from ambient air with advantageous time and cost efficiency.

[0016] Furthermore, it was an object of the present invention that the DAC system to be specified should exhibit advantageous durability. A desirable requirement in this regard was that the DAC system to be specified should be able to operate reliably for as long as possible with minimal maintenance. In addition, it was aimed that the solution to be specified should be applicable to a wide range of different chemical-technical concepts for the production of carbon dioxide and thus to a large variety of different DAC systems.

[0017] A further objective of the present invention was that the solution to be provided should make it possible to retrofit a large number of existing DAC systems with the least possible effort.

[0018] A further objective of the present invention was to ensure that the DAC system to be specified should be particularly reliable in its operation and that the solution to be specified itself should be able to do without the use of substances that are harmful to health and / or the environment, if possible.

[0019] Furthermore, it was an object of the present invention to provide an advantageous method for the chemical-technical recovery of carbon dioxide from ambient air using a DAC system of a specified type. It was also an object of the present invention to provide an advantageous use of a pre-filter arrangement in DAC systems to increase the service life of the CO2 capture units used in the DAC system.

[0020] A further object of the present invention was to provide an advantageous pre-filter arrangement for use in DAC systems as well as a pre-filter insert usable in such pre-filter arrangements.

[0021] The inventors of the present invention have now found that the CCh separation units used in DAC systems for separating carbon dioxide from the ambient air are impaired by gaseous interfering compounds, such as sulfur dioxide and nitrogen dioxide, which are contained in the ambient air, and that this impairment can be prevented by providing an advantageous pre-filter arrangement in a DAC system, which includes a particle filter element for separating particulate contaminants from the ambient air and a specific adsorption element, which comprises a porous adsorption material for the physical and / or chemical adsorption of gaseous interfering compounds present in the ambient air, as defined in the claims.

[0022] The aforementioned problems are thus solved by the subject matter of the invention as defined in the claims. Preferred embodiments of the invention are described in the dependent claims and the following descriptions.

[0023] Such embodiments, which are hereinafter referred to as preferred, are combined in particularly preferred embodiments with features of other embodiments referred to as preferred. Combinations of two or more of the embodiments referred to below as particularly preferred are therefore especially preferred. Also preferred are embodiments in which a feature of one embodiment referred to as preferred to any extent is combined with one or more further features of other embodiments referred to as preferred to any extent. Features of preferred methods and uses, as well as pre-filter arrangements and pre-filter elements, are derived from the features of preferred DAC systems. Particularly preferred embodiments of the invention are disclosed in the exemplary embodiments.Particularly preferred embodiments of the invention have two or more, preferably three or more, and most preferably four or more, of the preferred features of the invention disclosed below, which are also realized in the exemplary embodiments.

[0024] The invention relates in particular to a DAC plant for the chemical-technical recovery of carbon dioxide from ambient air, comprising: i) a CCh separation unit for separating carbon dioxide from ambient air, and ii) an air supply system for supplying ambient air to the CCh separation unit, characterized in that the DAC plant comprises a pre-filter arrangement, wherein the pre-filter arrangement comprises:

[0025] I) a particle filter element for separating particulate contaminants from the ambient air, comprising a filter medium, and

[0026] II) an adsorption element comprising a porous adsorption material for the physical and / or chemical adsorption of one or more gaseous pollutants from the ambient air, wherein the gaseous pollutants are selected from the group consisting of ammonia, ozone, hydrogen sulfide, sulfur oxides, nitrogen oxides and volatile organic compounds, which have a vapor pressure of 0.01 kPa or more at 20 °C, wherein the DAC system is designed such that the ambient air supplied to the CO2 separation unit is passed through the particle filter element and the adsorption element before the CO2 separation unit.

[0027] The invention relates to a DAC system, i.e., a system for "Direct Air Capture". DAC systems are generally known to those skilled in the art and are used for the chemical-technical extraction of carbon dioxide from ambient air. DAC systems are offered or developed by many commercial suppliers. DAC systems can be based on a wide variety of different concepts that serve to extract carbon dioxide from ambient air.

[0028] A major advantage of the present invention is that the identified solution can be advantageously applied to a wide range of different DAC systems and, in particular, also enables the advantageous retrofitting of existing DAC systems. The inventors believe that the vast majority of DAC systems relevant in practice will be stationary, which may, for example, be structurally connected to the ground. In accordance with expert understanding, this means that the DAC systems are stationary, i.e., immobile, in their intended operating state. This does not preclude the possibility of relocating such DAC systems, for example, by means of heavy transport, given sufficient effort.A DAC system according to the invention is therefore preferred, wherein the DAC system is a stationary DAC system, and / or wherein the DAC system is a physical installation.

[0029] A person skilled in the art understands that the DAC system according to the invention is a system specifically designed to extract carbon dioxide from ambient air. This means that the DAC system is configured to extract carbon dioxide from a fluid with a relatively low carbon dioxide concentration. A DAC system according to the invention is preferred in substantially all embodiments, wherein the combined volume fraction of CO2 in the ambient air is 0.5% or less, preferably 0.2% or less, particularly preferably 0.1% or less, and most preferably 0.05% or less.

[0030] The person skilled in the art understands that the DAC system according to the invention is not, in particular, a "Point Source Capture" (PSC) system. Therefore, a DAC system according to the invention is particularly relevant if it is a freestanding system, preferably located on an undeveloped open space, and / or if the DAC system is not connected to an industrial carbon dioxide source via the air distribution system, and / or if the DAC system is not part of an exhaust gas treatment system, especially of carbon dioxide-producing industrial plants or vehicles.

[0031] The DAC system according to the invention comprises, as part of the section intended for the chemical-technical production of carbon dioxide, a CO2 separator unit, which is designed to enable the separation of carbon dioxide from the ambient air. Such CO2 separator units are generally known from the prior art.

[0032] In principle, it is conceivable that the DAC system according to the invention could also comprise several CCh deposition units. Of particular relevance for later practical application are those DAC systems that are configured so that the various CCh deposition units can be operated alternately, ensuring that deposition is always taking place while other CCh deposition units are undergoing regeneration or are in standby mode. A DAC system according to the invention is therefore preferred, wherein the DAC system comprises two or more, preferably four or more, and particularly preferably eight or more, CCh deposition units.A DAC system according to the invention is preferred additionally or alternatively, wherein the DAC system comprises two or more, preferably three or more, CCh deposition units, wherein the DAC system is preferably configured such that at least one of the CCh deposition units is in an operating mode while at least one other CCh deposition unit is in a standby mode or a regeneration mode.

[0033] As explained above, it can be seen as an advantage of the DAC systems according to the invention that the advantageous solution concept can be applied to a wide range of CCh deposition units, so that the person skilled in the art can essentially make use of all technologies available on the market for the CCh deposition units when implementing the invention and thereby achieve an improvement.An example of a DAC system according to the invention is the CCh separation units, wherein the CCh separation units are selected from the group consisting of adsorptive CO2 separation units, absorptive CO2 separation units, electrochemical CO2 separation units, membrane-based CO2 separation units, biochemical CO2 separation units and biological CO2 separation units, preferably selected from the group consisting of adsorptive CO2 separation units, absorptive CO2 separation units and electrochemical CO2 separation units, and particularly preferably selected from the group consisting of adsorptive CO2 separation units.

[0034] However, the inventors' experiments have shown that the use of a pre-filter arrangement as provided for in the invention offers particularly great advantages when operating with certain CO2 separation units.A preferred DAC system according to the invention comprises one or more porous CC>2 adsorbents selected from the group consisting of ion exchange materials, impregnated amorphous silicon dioxide, chemically functionalized amorphous silicon dioxide and metal-organic frameworks, preferably selected from the group consisting of ion exchange materials functionalized with basic functional groups, silicon dioxide impregnated with amine compounds, silicon dioxide chemically functionalized with amino groups and metal-organic frameworks, and particularly preferably selected from the group consisting of ion exchange materials functionalized with amino groups, wherein the term amino groups within the scope of the present invention includes primary, secondary and tertiary amino groups.A DAC system according to the invention is preferred, either additionally or alternatively, wherein the CO2 separation units comprise one or more porous support materials impregnated with ionic liquids. A DAC system according to the invention is again preferred, either additionally or alternatively, wherein the CO2 separation units comprise one or more porous CO2 adsorbents selected from the group consisting of divinylbenzene-crosslinked polymers, preferably divinylbenzene-crosslinked polymers functionalized with basic functional groups, and particularly preferably divinylbenzene-crosslinked polymers functionalized with amine groups, especially primary amine groups. Suitable materials are available, for example, under the trade name Lewatit VP OC 1065.

[0035] In particularly preferred embodiments, the DAC system, via the CO2 separation units employed, is not only configured to separate CO2 from the ambient air, but is also capable of releasing it again as needed, so that the separated CO2 can, for example, be stored or used in a downstream application. Accordingly, a DAC system according to the invention is preferred in which the CO2 separation units are configured to separate carbon dioxide from the ambient air and release it again following one or more regeneration operations.A DAC system according to the invention is particularly preferred, wherein the regeneration operation is selected from the group consisting of temperature changes, pressure changes and changes in humidity, concentration changes, changes in the electromagnetic field, for example as a result of a change in electrical voltage or a change in a magnetic field, application of electromagnetic radiation and combinations of these methods, preferably selected from the group consisting of temperature changes.

[0036] In addition to the CO2 separation units, the DAC system according to the invention also includes an air distribution system configured to supply ambient air to the CO2 separation units. A preferred DAC system according to the invention comprises one or more devices for moving ambient air, in particular one or more fans.

[0037] With regard to the design, it is particularly advantageous to integrate the pre-filter arrangement disclosed below into the air distribution system. A DAC system according to the invention is therefore preferred, wherein the pre-filter arrangement is integrated into the air distribution system.

[0038] According to the invention, the DAC system also includes a pre-filter arrangement. The term "pre-filter arrangement" indicates that it can be an assembly of several components located upstream of the CCh separation units of the DAC system. In particular, it is advantageously possible to design the components of the pre-filter arrangement to be reversibly and non-destructively replaceable, thus reducing maintenance effort. A DAC system according to the invention is therefore preferred in which the particle filter element and / or the adsorption element, preferably both the particle filter element and the adsorption element, are arranged in the pre-filter arrangement in a reversibly and non-destructively replaceable manner.A DAC system according to the invention is preferred additionally or alternatively, wherein the particle filter element and the adsorption element are integrated into a pre-filter insert, wherein the pre-filter insert is preferably arranged in the pre-filter arrangement in a reversible and non-destructively replaceable manner.

[0039] To reduce waste generation, it is also preferred to design the pre-filter assembly or the elements installed therein as regenerable, so that their performance can be increased through suitable regeneration measures, for example, by thermal treatment and / or cleaning in a cleaning fluid. A DAC system according to the invention is therefore preferred, wherein the pre-filter assembly is a regenerable pre-filter assembly. The pre-filter assembly to be used according to the invention initially comprises a particle filter element. This particle filter element is designed to remove particulate contaminants from the ambient air. This advantageously prevents these particulate contaminants from entering the CO2 separation units via the ambient air, thereby increasing the service life and also the performance of the corresponding CCh separation units.

[0040] To achieve the purpose of the particle filter element, the particle filter element comprises a filter medium. A DAC system according to the invention is conceivable, wherein the particle filter element comprises two or more filter media, or wherein the particle filter stage consists of a single filter medium.

[0041] In principle, any type of typical filter media used in filtration technology can be advantageously employed. However, considering the very specific requirements of DAC systems, the inventors have identified the use of polymer-based filter media as particularly beneficial, as these consistently offer excellent durability and long-term filtration performance even under the expected environmental conditions.A DAC system according to the invention is preferred, either additionally or alternatively, wherein the filter medium consists at least partially, preferably predominantly, and particularly preferably substantially entirely of a plastic, preferably a thermoplastic plastic, wherein the thermoplastic plastic is preferably selected from the group consisting of polyolefins, polyamides, polyurethanes, polycarbonates, and polyesters, particularly preferably from the group consisting of polyolefins and polyesters, and most preferably from the group consisting of polyesters. A DAC system according to the invention is also preferred, either additionally or alternatively, wherein the filter medium is selected from the group consisting of textile fabrics, preferably from the group consisting of nonwovens, in particular meltblown nonwovens and spunbond nonwovens.

[0042] Preferably, or alternatively, a DAC system according to the invention is used, wherein the filter medium has a basis weight in the range of 20 to 300 g / m². 2 , preferably in the range of 40 to 200 g / m³ 2 , particularly preferably in the range of 50 to 150 g / m³ 2 Preferably, or alternatively, a DAC system according to the invention is used, wherein the filter medium has a density of 1000 kg / m³. 3 or smaller, preferably 800 kg / m² 3 or smaller, especially preferably 600 kg / m² 3 or smaller.

[0043] Preferably, or alternatively, a DAC system according to the invention is used, wherein the filter element has an air passage according to DIN EN ISO 9237:1995-12 in the range of 100 to 10000 L / (s*m²). 2 ), preferably in the range of 200 to 5000 L / (s*m³) 2 ), particularly preferably in the range of 500 to 4000 L / (s*m³). 2 ).

[0044] A DAC system according to the invention is preferred, either additionally or alternatively, wherein the filter medium consists at least partially, preferably predominantly, and particularly preferably essentially entirely of an electret material, preferably in the form of a triboelectric fleece.

[0045] Electret materials are generally known to experts in the field of filtration technology and are commercially available from various manufacturers. Electret materials are materials with low electrical conductivity in which, through the manufacturing process and / or subsequent processing, a largely permanently stored electrical charge is introduced or an essentially permanent alignment of the electric dipoles within the material is created. Thus, electret materials exhibit an electric field, which is why they are sometimes compared to permanent magnets.Electret materials are produced in the prior art using various methods, which are based in particular on injecting free charge carriers into the non-conductive base material or on bringing about a permanently oriented orientation of the dipoles in this non-conductive base material, for example by manufacturing within a strong electric field.

[0046] In the field of filtration technology, the use of electret materials in so-called electret filters is known, which rely on the inherent electrical charge of the electret materials. A DAC system according to the invention is particularly preferred, wherein the electret material is a fibrous plastic material, and the plastic material is preferably selected from the group consisting of polyolefins, in particular polytetrafluoroethylene, polytetrafluoroethylene propylene, polypropylene and polyethylene, polyesters, in particular polyethylene terephthalate, polycarbonates, polyamides, polyvinylidene fluoride, polyacrylonitrile, and polylactides. A DAC system according to the invention is additionally or alternatively preferred, wherein the specific electrical resistance of the electret material at 20 °C is 10 8 Q mm 2 / m or more, preferably at 10 10 Q mm 2 / m or more, especially preferred at 10 12 Q mm 2 / m or more, lies.

[0047] The inventors of the present invention have recognized that the advantageous effect of using the pre-filter arrangement can be further increased if it is also used to prevent colonization of the CCh-free separation units by microorganisms. A DAC system according to the invention is preferred, wherein the particle filter element and / or the adsorption element comprises an antimicrobial coating, preferably an antibacterial coating.

[0048] At least in principle, it is desirable to remove potentially disruptive particles as completely as possible with the particle filter element, so that ambient air is obtained that is as particle-free as possible. Accordingly, a DAC system according to the invention is preferred, wherein the particle filter element is configured to prevent the passage of particles with a particle size of 10 pm or more, preferably 5 pm or more, particularly preferably 2 pm or more, very preferably 1 pm or more, and particularly preferably 0.2 pm or more, through the particle filter element by 95% or more, preferably 98% or more, and particularly preferably 99% or more.

[0049] However, the inventors' experiments have shown that for many DAC systems, it is advantageously not necessary to achieve very high filtration efficiencies with respect to particles. Rather, it is advantageously possible to use coarser filter media, which in particular enables the achievement of advantageous back pressures. A DAC system according to the invention is preferably configured in which the particle filter element is designed to prevent the passage of particles with a particle size of 0.3 pm or more, preferably 2.5 pm or more, and particularly preferably 10 pm or more, through the particle filter element by 40% or more, preferably 50% or more, and particularly preferably 60% or more.A DAC system according to the invention is preferred, either additionally or alternatively, wherein the particle filter element has a filter class according to EN 779:2012 of G3 or better, preferably M6 or better, and / or wherein the particle filter element has a filter class according to ISO 16890:2018 of ISO Coarse 50 or better, preferably ePM 75% or better. To increase the available inflow area of ​​the filter medium within a given installation space, it is advantageous to use pleated filter media. A DAC system according to the invention is therefore preferred, wherein the particle filter element comprises a pleated or wound, preferably pleated, filter medium, the filter medium preferably comprising a plurality of substantially uniform pleats. A DAC system according to the invention is also preferred, either additionally or alternatively, wherein the adsorption element is a pleated adsorption element, preferably with a pleat complementary to the pleated filter medium.Furthermore, possible designs include, for example, combination coil filters, combination pleat filters, or combination pleat pour filters.

[0050] In addition to the particle filter element and the filter medium it contains, the pre-filter arrangement to be used according to the invention also includes an adsorption element. This element comprises a porous adsorption material configured to adsorb one or more gaseous contaminants by physical and / or chemical adsorption, thereby reducing their concentration in the treated ambient air, preferably by 10% or more, particularly preferably by 20% or more, and most preferably by 50% or more. The adjective "porous" is clear to those skilled in the art and can be readily understood in practice. It expresses the fact that the adsorption material comprises cavities, with the porous adsorption material preferably having a high proportion of accessible cavities and thus a high usable porosity. Preferably, the porous adsorption material comprises micropores, mesopores, and / or macropores.

[0051] Regarding the design of the pre-filter assembly, in conjunction with the particle filter element and the adsorption element, it is preferred for some applications to design these as separate elements. A spaced-apart arrangement of the two elements allows, in particular, the selective replacement of only one element, thus enabling independent design of maintenance and replacement intervals. Alternatively, it is possible to at least partially connect the particle filter element and the adsorption element, for example, by incorporating the porous adsorption material into the filter medium. A DAC system according to the invention is also preferred, or alternatively, wherein the particle filter element and the adsorption element are formed by separate elements, and / or wherein the particle filter element and the adsorption element are at least partially integrated into a single element.The person skilled in the art understands that the adsorption element to be provided according to the invention can, in principle, comprise not only the porous adsorption material but also other components that, for example, serve to give the adsorption element a certain rigidity or to influence its handling properties. At the same time, the person skilled in the art also understands that the adsorption properties of the adsorption element will depend significantly on the amount of adsorption material incorporated into the adsorption element. To achieve the greatest possible adsorption effect within a given installation space, it is accordingly preferred to make the adsorption element as largely as possible from the adsorption material. A DAC system according to the invention is therefore preferred, wherein the adsorption element consists of the adsorption material to a mass fraction of 50% or more, preferably 70% or more, particularly preferably 90% or more, and most preferably 95% or more.A DAC system according to the invention is preferred additionally or alternatively, wherein the adsorption element has an area weight in the range of 150 to 1500 g / m². 2 , preferably in the range of 500 to 1500 g / m³ 2 , particularly preferably in the range of 600 to 1200 g / m³ 2 , features. Preferably, or alternatively, a DAC system according to the invention is also present, wherein the adsorption element comprises a layer of the adsorption material.

[0052] The porous adsorption materials to be used according to the invention are defined above by their suitability for adsorbing specific gaseous interfering compounds and reducing their concentration in the processed ambient air. The inventors of the present invention have recognized that, in addition to volatile organic compounds (VOCs), acidic gases in particular can have a detrimental effect on the downstream CO2 separation units, with sulfur oxides and nitrogen oxides being identified as being particularly detrimental. A DAC system according to the invention is preferred, wherein the gaseous interfering compounds are selected from the group consisting of ammonia, hydrogen sulfide, sulfur oxides, and nitrogen oxides, and particularly preferably from the group consisting of sulfur oxides and nitrogen oxides, especially SO2 and NO2. A method according to the invention is additionally or alternatively preferred.The volatile organic compounds are selected from the group consisting of benzene, toluene, xylene, formaldehyde, alcohols, aldehydes, carboxylic acids, carboxylic esters, amines, amides, imides, and alkanes. Porous adsorption materials suitable for the physical and / or chemical adsorption of the aforementioned gaseous interfering compounds are known in principle from other fields of application and are commercially available from numerous suppliers. The adsorption capacity with respect to the gaseous interfering compounds is usually specified in the product information for the commercially available materials. Against this background, the inventors recommend that the person skilled in the art should expediently check the respective CCh separation unit used to determine which gaseous interfering compounds it is particularly susceptible to and select the adsorption material accordingly.that it has a high adsorption capacity for the corresponding gaseous interfering compounds. This can be achieved by simple conditioning experiments, as are disclosed below. An exemplary method according to the invention is described, wherein the adsorption material comprises one or more, preferably two or more, particularly preferably three or more, materials selected from the group consisting of: i) catalytically active materials, in particular catalytically active metals and metal oxides, for example the metals Ti, Zr, Hf, Fe, Ru, Os, Ni, Pd, Pt, Co, Rh, Ir, Cu, Ag, Au, Mn, Re and / or Zn, ii) organic framework compounds, for example metal-organic frameworks (MOF), covalent-organic frameworks (COF), ion exchange materials and zeolite-imidazole frameworks (ZIF), iii) porous carbon modifications, for example activated carbon, carbon molecular sieve (CMS), carbon nanotubes (CNT), graphite, graphene,iv) Zeolites and clay minerals, v) functionalized polymers, for example ion exchange materials, and vi) impregnated and / or functionalized porous support materials, for example impregnated amorphous silicon dioxide or functionalized zeolites.

[0053] Particularly preferred is a method according to the invention, wherein the adsorption material comprises one or more, preferably two or more, particularly preferably three or more, materials selected from the group consisting of: ii) organic framework compounds, v) functionalized polymers, and vi) impregnated and / or functionalized porous support materials.

[0054] As explained above, an advantage of the invention is that a wide range of materials commercially available from various manufacturers can be used for the porous adsorption materials, and these materials are known for their adsorption capacity for the gaseous interfering compounds. Among the multitude of possible adsorption materials, however, the inventors have succeeded in identifying particularly suitable materials for use in DAC systems, where excellent results can be achieved when used in the pre-filter arrangement of corresponding DAC systems, especially with regard to the removal of the sulfur oxides and nitrogen oxides, which have been identified as particularly detrimental.A DAC system according to the invention is particularly preferred, wherein the adsorption material comprises one or more, preferably two or more, and particularly preferably three or more, materials selected from the group consisting of unimpregnated activated carbon, impregnated activated carbon, ion exchange materials, and catalytically active materials. A DAC system according to the invention is additionally or alternatively preferred, wherein the adsorption material is at least partially functionalized on its surface with basic functional groups, in particular amino groups.

[0055] Particularly preferred is a DAC system according to the invention, wherein the adsorption material comprises one or more, preferably two or more, particularly preferably three or more, materials selected from the group consisting of impregnated activated carbon and activated activated carbon, preferably selected from the group consisting of basic impregnated activated carbon and nitrogen-activated activated carbon.

[0056] When activated carbon is preferably used, a DAC system according to the invention is particularly preferred, wherein the activated carbon is produced or producible from renewable raw materials, preferably plant-based raw materials, and particularly preferably from coconut shells and / or macadamia nut shells. Production from renewable raw materials can be determined using the 14C method according to ASTM D6866-24. The inventors point out that there may be some overlap between materials that allow adsorption of the relevant gaseous interfering compounds and materials that can be used in CO2 capture units, at least with regard to the general classes of substances.In this respect, it is preferred for essentially all embodiments if the adsorption material differs from the material used in the CO2 separation units in order to ensure a different separation profile, in which as little CO2 as possible is separated from the gaseous interfering compounds in the pre-filter arrangement.A DAC system according to the invention is particularly preferred, wherein the CCh separation unit comprises a porous separation material for separating carbon dioxide from the ambient air, wherein the porous separation material and the porous adsorption material comprise different materials, wherein the porous separation material and the porous adsorption material preferably consist of different materials to a mass fraction of 90% or more, particularly preferably 95% or more, most preferably 98% or more, and particularly preferably substantially 100%, based on the mass of the respective materials.

[0057] A DAC system according to the invention is also preferred with regard to the design of the adsorption element, wherein the adsorption element has an air passage according to DIN EN ISO 9237:1995-12 in the range of 100 to 10000 L / (s*m²). 2 ), preferably in the range of 200 to 5000 L / (s*m³) 2), particularly preferably in the range of 500 to 4000 L / (s*m³). 2 ).

[0058] The inventors recognized that a particular challenge for the operation of a pre-filter arrangement in conventional DAC systems can arise from the relatively direct influence of ambient humidity. For this reason, the inventors identified it as particularly advantageous to take measures to prevent water from the ambient air or even splash water from entering the pre-filter arrangement. Specifically, a DAC system according to the invention is preferred in which the pre-filter arrangement additionally comprises:

[0059] III) a droplet separator for separating liquid droplets from the ambient air, and / or

[0060] IV) a splash guard to prevent splash water from penetrating the other components of the pre-filter assembly. Furthermore, the inventors' experiments have shown that particularly efficient DAC systems according to the invention can be obtained if, in addition to the other components, a separation element is also provided, which serves to further separate oxygen and / or gaseous water from the ambient air. This can be achieved in particular by using a semipermeable membrane or another adsorption material. This advantageously improves the performance and durability of the CCh separation units. A DAC system according to the invention is therefore preferred, wherein the pre-filter assembly additionally comprises:

[0061] V) a separating element comprising

[0062] Vi) a semipermeable membrane for separating oxygen and / or water, and / or

[0063] V.ii) comprises a further adsorption material for the physical and / or chemical adsorption of oxygen and / or water. Preferably, or alternatively, a DAC system according to the invention is included, wherein the DAC system is designed such that the ambient air supplied to the CO2 separation unit is guided through the separation element after the particle filter element. Preferably, or alternatively, a DAC system according to the invention is included, wherein the droplet separator is arranged such that it is subjected to the flow of ambient air in the air duct system in the DAC system, upstream of the particle filter element, preferably upstream of the particle filter element and the adsorption element.

[0064] A DAC system according to the invention is preferred, either additionally or alternatively, wherein at least one filter medium is selected from the group consisting of combination filter media, honeycombs, extrudates, packed materials, fiber media, foams, sintered filter media and adsorbents fixed or granulated on the aforementioned filter media, wherein the fixing can be carried out, for example, with organic or inorganic binders or thermally.

[0065] A DAC system according to the invention is also preferred, either additionally or alternatively, wherein the pre-filter arrangement is designed as a V-bank filter, preferably as a 4-V-bank filter or as a 3-V-bank filter. Corresponding V-bank filters are known from the field of building ventilation and air conditioning technology (HVAC applications) and are suitable as a design for the present pre-filter arrangements.

[0066] The invention further relates to a process for the chemical-technical recovery of carbon dioxide from ambient air using a DAC system according to the invention, comprising the following process steps for obtaining treated ambient air: a) separating particulate impurities from the ambient air with the particle filter element, and b) adsorbing gaseous impurities from the ambient air with the adsorption element, wherein the gaseous impurities are selected from the group consisting of ammonia, ozone, hydrogen sulfide, sulfur oxides, nitrogen oxides and volatile organic compounds, which have a vapor pressure of 0.01 kPa or more at 20 °C, as well as the process step: c) recovering carbon dioxide from the treated ambient air with a CO2 separation unit.

[0067] In the process according to the invention, carbon dioxide is chemically extracted from ambient air using a DAC system according to the invention. The particle filter element used in the pre-filter arrangement of the DAC system is employed to remove particulate impurities from the ambient air, while the gaseous contaminants are adsorbed by the adsorption element. Carbon dioxide is then extracted from the thus treated ambient air using the CO2 separation unit of the DAC system according to the invention. The carbon dioxide thus obtained can be stored, in particular, in a CO2 storage system or processed directly in downstream process steps, which is referred to within the scope of the present invention as the CO2 processing unit.A preferred method according to the invention therefore includes the recovery of carbon dioxide, comprising the regeneration of the CO2 capture unit for the release or direct use of carbon dioxide captured from the ambient air. A preferred method according to the invention further comprises, or is alternatively preferred, the process step of: d) storing the recovered carbon dioxide in a CO2 storage system and / or processing the recovered carbon dioxide in a CC>2 processing unit.

[0068] The inventors propose that the inventive method offers particularly significant advantages when the proportion of gaseous interfering compounds in the treated ambient air is kept as low as possible, which can be advantageously achieved through the design of the inventive DAC system and, in particular, the corresponding pre-filter arrangement. A preferred method according to the invention is one in which the treated ambient air has a combined volume fraction of gaseous interfering compounds of 30 ppb or less, preferably 15 ppb or less, and most preferably 10 ppb or less, based on the volume of the treated ambient air, and / or in which the combined volume fraction of gaseous interfering compounds in the ambient air is reduced in process step b) by 50% or more, preferably 70% or more, most preferably 80% or more, and most preferably 90% or more.

[0069] It is preferred to design the pre-filter arrangement such that it allows good airflow through it. A preferred method according to the invention is one in which, at a volume flow rate of 3000 m³ / h, 3 / h the differential pressure at the pre-filter arrangement is 1000 Pa or less, preferably 600 Pa or less, particularly preferably 300 Pa or less.

[0070] The inventors of the present invention have recognized that it is also advantageous to design the DAC system according to the invention in such a way that the volume fraction of carbon dioxide in the ambient air is reduced as little as possible by the preceding treatment, in order to avoid reducing the efficiency of the downstream CCh separation units. This can be achieved particularly well by the porous adsorption materials identified as preferred. A preferred method according to the invention is therefore one in which the volume fraction of carbon dioxide in the ambient air is reduced by 0.5% or less, preferably 0.2% or less, and particularly preferably 0.1% or less, in a process step between the ambient air and the treated ambient air, and / or in which the porous adsorption materials comprise 0.3% or less, preferably 0.2% or less, and particularly preferably 0.1% or less, of the CC>2 capacity of the CCh separation unit.The invention further relates to the use of a pre-filter arrangement in DAC systems to increase the service life of system components used in the DAC system, in particular the CO2 separation units, by prior treatment of the ambient air supplied to the CCh separation units, wherein the pre-filter arrangement comprises:.

[0071] I) a particle filter element for separating particulate contaminants from the ambient air, and

[0072] II) an adsorption element comprising a porous adsorption material for the physical and / or chemical adsorption of one or more gaseous pollutants from the ambient air, wherein the gaseous pollutants are selected from the group consisting of ammonia, ozone, hydrogen sulfide, sulfur oxides, nitrogen oxides and volatile organic compounds, which have a vapor pressure of 0.01 kPa or more at 20 °C.

[0073] The invention also relates to a pre-filter arrangement for use in DAC systems, in particular DAC systems according to the invention, wherein the pre-filter arrangement comprises:

[0074] I) a particle filter element for separating particulate contaminants from the ambient air, comprising a filter medium, and

[0075] II) an adsorption element comprising a porous adsorption material for the physical and / or chemical adsorption of one or more gaseous pollutants from the ambient air, wherein the gaseous pollutants are selected from the group consisting of ammonia, ozone, hydrogen sulfide, sulfur oxides, nitrogen oxides and volatile organic compounds, which have a vapor pressure of 0.01 kPa or more at 20 °C, wherein the pre-filter arrangement is preferably designed to allow air to be filtered to pass through the particle filter element and the adsorption element.

[0076] The invention also relates to a pre-filter insert for a pre-filter arrangement according to the invention for use in DAC systems, comprising integrated into the pre-filter insert: I) a particle filter element for separating particulate contaminants from the ambient air, comprising a filter medium and

[0077] II) an adsorption element comprising a porous adsorption material for the physical and / or chemical adsorption of one or more gaseous pollutants from the ambient air, wherein the gaseous pollutants are selected from the group consisting of ammonia, ozone, hydrogen sulfide, sulfur oxides, nitrogen oxides and volatile organic compounds, which have a vapor pressure of 0.01 kPa or more at 20 °C, wherein the pre-filter insert is preferably designed to allow air to be filtered to pass through the particle filter element and the adsorption element.

[0078] Features of preferred pre-filter arrangements and pre-filter inserts according to the invention result from the features of preferred DAC systems, in particular with regard to the design of the particle filter element, the filter medium, the adsorption element and the porous adsorption material.

[0079] Particularly preferred are pre-filter arrangements and pre-filter inserts according to the invention, wherein the filter medium consists at least partially of a plastic, and / or wherein the filter medium is selected from the group consisting of textile sheet structures, and / or wherein the particle filter element and / or the adsorption element comprise an antimicrobial coating, and / or wherein the particle filter element has a filter class according to EN 779:2012 of G3 or better, and / or wherein the particle filter element and the adsorption element are at least partially integrated into one element, and / or wherein the gaseous interfering compounds are selected from the group consisting of

[0080] ammonia, hydrogen sulfide, sulfur oxides and nitrogen oxides, and / or wherein the adsorption material comprises one or more, preferably two or more, particularly preferably three or more, materials selected from the group consisting of unimpregnated activated carbon, impregnated activated carbon, ion exchange materials and catalytically active materials, preferably selected from the group consisting of unimpregnated activated carbon, impregnated activated carbon and ion exchange materials.

[0081] Preferably, or alternatively, pre-filter arrangements and pre-filter inserts according to the invention are further comprising:

[0082] III) a droplet separator (24) for separating liquid droplets from the ambient air (12), and / or

[0083] IV) a splash guard (26) to prevent splash water from entering the other components of the pre-filter assembly (18), and / or

[0084] V) a separating element (28) comprising

[0085] Vi) a semipermeable membrane for separating oxygen and / or water, and / or

[0086] V.ii) comprises a further adsorption material for the physical and / or chemical adsorption of oxygen and / or water.

[0087] The invention and preferred embodiments of the invention are explained and described in more detail below with reference to the accompanying figures. The figures show:

[0088] Fig. 1 is a schematic representation of a DAC system according to the invention in a preferred embodiment;

[0089] Fig. 2 shows a schematic representation of an advantageous pre-filter arrangement for use in DAC systems according to the invention in a first preferred embodiment; Fig. 3 shows a schematic representation of an advantageous pre-filter arrangement for use in DAC systems according to the invention in a second preferred embodiment;

[0090] Fig. 4 shows a schematic representation of an advantageous pre-filter arrangement for use in DAC systems according to the invention in a third preferred embodiment;

[0091] Fig. 5 shows a graphical representation of the CCh capacity loss for different CCh adsorbents during e) initial measurement and after 3.6-hour conditioning with 1200 ppb nitrogen dioxide, f) without and g) with pre-filter arrangement; and

[0092] Fig. 6 shows a graphical representation of the CCh capacity loss for different CCh adsorbents during e) initial measurement and after two hours of conditioning with 600 ppb sulfur dioxide, f) without and g) with pre-filter arrangement.

[0093] Fig. 1 shows a DAC plant 10 according to the invention for the chemical-technical production of carbon dioxide from ambient air 12 in a preferred embodiment, which can in particular be designed as a freestanding DAC plant 10. The DAC plant 10 comprises as a central functional element a CCh separation unit 14 for separating carbon dioxide from the ambient air 12, wherein the CCh separation unit 14 can, for example, be based on the materials used in Fig. 5 and Fig. 6.

[0094] The CCh separation unit 14 is supplied with ambient air 12 via an air distribution system 16, whereby the supply can be effected, for example, by a fan system. A pre-filter arrangement 18 is integrated into the air distribution system 16 such that the ambient air 12 supplied to the CO2 separation unit 14 is passed through the pre-filter arrangement 18 before reaching the CCh separation unit 14.

[0095] In the example shown in Fig. 1, the pre-filter arrangement 18 is designed as a reversibly and non-destructively replaceable pre-filter element, whereby pre-filter arrangements 18 can be used as shown in Figs. 2 to 4. Downstream of the pre-filter arrangement 18, conditioned ambient air 30 is obtained, which has been largely freed not only of particles but also, in particular, of gaseous contaminants such as SO2 and NO2, thereby increasing the efficiency of the DAC system 10 and extending the service life of the CCh separation unit 14.

[0096] Behind the CCh separation unit 14, CCh-poor exhaust air 32 is discharged, whereas the CO2 product stream 34 can be supplied to storage or further processing.

[0097] Fig. 2 shows a schematic representation of an advantageous pre-filter arrangement 18 for use in DAC systems 10 according to the invention in a first preferred embodiment, which is particularly easy to implement in terms of construction. The pre-filter arrangement 18 comprises, on the upstream side, a particle filter element 20a for separating particulate contaminants from the ambient air 12, behind which, in the direction of flow, an adsorption element 22 is located, which comprises a porous adsorption material for the physical and / or chemical adsorption of one or more gaseous contaminants from the ambient air 12.

[0098] The pre-filter assembly 18 shown in Fig. 2 comprises a pleated spunbond nonwoven fabric made of polyester, coated with an antibacterial coating, as the particle filter element 20a. In the example shown, the particle filter element 20a has a filter class of ISO Coarse 50 according to ISO 16890:2018. The adsorption element 22 can be spaced apart from the particle filter element 20a or integrated into the meltblown nonwoven fabric. The pre-filter assembly 18 of Fig. 2 has a multi-layered structure with a total basis weight of 720 g / m². 2 .

[0099] The adsorption element 22 consists essentially entirely of an adsorption material and serves for the physical and / or chemical adsorption of gaseous contaminants from the ambient air 12. In the example shown in Fig. 2, the adsorption material is activated carbon impregnated with potassium carbonate (10% potassium carbonate impregnation; DGK 30x60 KC10).

[0100] Fig. 3 shows a schematic representation of an advantageous pre-filter arrangement 18 for use in DAC systems 10 according to the invention in a second preferred embodiment, in which a second particle filter element 20b is located downstream of the adsorption element 22, which can be designed analogously to the first particle filter element 20a. Fig. 4 shows a schematic representation of an advantageous pre-filter arrangement 18 for use in DAC systems 10 according to the invention in a third preferred embodiment, wherein a splash guard 26 and a droplet separator 24 are located upstream of the basic structure of Fig. 2, which protect the downstream components of the DAC system 10. A membrane-based separation element 28 is also provided downstream of the adsorption element 22, which serves to separate gaseous water.

[0101] Figures 5 and 6 show, for four exemplary media that can be used in CC>2 separation units 14, how their relevant CCh capacity is reduced from the new state e) by conditioning with an interfering compound f), and that the use of a pre-filter arrangement 18 during conditioning g) advantageously improves the CC>2 capacity as a result of the conditioning. In Figure 5, the conditioning is carried out for 3.6 h with a conditioning fluid containing 1200 ppb nitrogen dioxide, whereas the conditioning in Figure 6 is carried out for 2 h with a conditioning fluid containing 600 ppb sulfur dioxide. The conditioning was performed at a temperature of 23 °C and a relative humidity of 50% with an airflow velocity of 7 cm / s. On the x-axis, X represents the CCh capacity. The measurement of the CCh capacity (at 400 ppm orp(CC>2) = 0.04 kPa) was determined based on measurements of the CO2 adsorption isotherms at T = 23 °C in the range of p = 0 - 1 bar, in accordance with DIN 66135 and in accordance with Thommes et al (see Thommes et al. "Physisorption of gases, with special reference to the evaluation of surface area and pore size distribution (IIIPAC Technical Report)" Pure and Applied Chemistry, vol. 87, no. 9-10, 2015, pp. 1051-1069).

[0102] The various adsorption materials used in the experiments shown in Fig. 5 and Fig. 6 are summarized in Table 1 below.

[0103] Table 1

[0104] Reference mark

[0105] 10 DAC system

[0106] 12 Ambient air

[0107] 14 CCh separation unit 16 Air distribution system

[0108] 18 Pre-filter arrangement

[0109] 20a, 20b particle filter element

[0110] 22 Adsorption element

[0111] 24 Droplet separators 26 Splash water protection

[0112] 28 separating element

[0113] 30 treated ambient air

[0114] 32 CC>2-arm exhaust

[0115] 34 CC>2 product stream

Claims

- 29 - Claims 1. DAC plant (10) for the chemical-technical recovery of carbon dioxide from ambient air (12), comprising: i) a CCh separation unit (14) for separating carbon dioxide from the ambient air (12), and ii) an air supply system (16) for supplying ambient air (12) to the CO2 separation unit (14), characterized in that the DAC plant (10) comprises a pre-filter arrangement (18), wherein the pre-filter arrangement (18) comprises: I) a particle filter element (20a, 20b) for separating particulate contaminants from the ambient air (12), comprising a filter medium, and II) an adsorption element (22) comprising a porous adsorption material for the physical and / or chemical adsorption of one or more gaseous pollutants from the ambient air (12), wherein the gaseous pollutants are selected from the group consisting of ammonia, ozone, hydrogen sulfide, sulfur oxides, nitrogen oxides and volatile organic compounds, which have a vapor pressure of 0.01 kPa or more at 20 °C, wherein the DAC system (10) is designed such that the ambient air (12) supplied to the CO2 separation unit (14) is passed through the particle filter element (20) and the adsorption element (22) before the CO2 separation unit (14).

2. DAC system (10) according to claim 1, wherein the DAC system (10) is a freestanding DAC system (10).

3. DAC system (10) according to one of claims 1 or 2, wherein the pre-filter arrangement (18) is integrated into the air duct system (16). - 30 - 4. DAC system (10) according to one of claims 1 to 3, wherein the filter medium consists at least partially of a plastic.

5. DAC system (10) according to one of claims 1 to 4, wherein the filter medium is selected from the group consisting of textile sheet structures.

6. DAC system (10) according to any one of claims 1 to 5, wherein the particle filter element (20a, 20b) and / or the adsorption element (22) comprise an antimicrobial coating.

7. DAC system (10) according to any one of claims 1 to 6, wherein the particle filter element (20a, 20b) has a filter class according to EN 779:2012 of G3 or better.

8. DAC system (10) according to one of claims 1 to 7, wherein the particle filter element (20a, 20b) and the adsorption element (22) are at least partially integrated into one element.

9. DAC system (10) according to any one of claims 1 to 8, wherein the gaseous interfering compounds are selected from the group consisting of ammonia, hydrogen sulfide, sulfur oxides and nitrogen oxides.

10. DAC system (10) according to any one of claims 1 to 9, wherein the adsorption material comprises one or more, preferably two or more, particularly preferably three or more, materials selected from the group consisting of unimpregnated activated carbon, impregnated activated carbon, ion exchange materials and catalytically active materials, Preferred materials are selected from the group consisting of unimpregnated activated carbon, impregnated activated carbon and ion exchange materials.

11. DAC system (10) according to one of claims 1 to 10, wherein the CCh separation unit (14) comprises a porous separation material for separating carbon dioxide from the ambient air (12), wherein the porous separation material and the porous adsorption material comprise different materials.

12. DAC system (10) according to one of claims 1 to 11, wherein the pre-filter arrangement (18) further comprises: III) a droplet separator (24) for separating liquid droplets from the ambient air (12), and / or IV) a splash guard (26) to prevent splash water from entering the other components of the pre-filter assembly (18).

13. DAC system (10) according to one of claims 1 to 12, wherein the pre-filter arrangement (18) further comprises: V) a separating element (28) comprising Vi) a semipermeable membrane for separating oxygen and / or water, and / or V.ii) comprises a further adsorption material for the physical and / or chemical adsorption of oxygen and / or water.

14. A method for the chemical-technical recovery of carbon dioxide from ambient air (12) using a DAC system (10) according to any one of claims 1 to 13, comprising, for obtaining treated ambient air (30), the process steps of: a) separating particulate impurities from the ambient air (12) using the particle filter element (20), and b) adsorbing gaseous impurities from the ambient air (12) using the adsorption element (22), wherein the gaseous impurities are selected from the group consisting of ammonia, ozone, hydrogen sulfide, sulfur oxides, nitrogen oxides and volatile organic compounds, which have a vapor pressure of 0.01 kPa or more at 20 °C, and the process step of: c) recovering carbon dioxide from the treated ambient air (30) using a CO2 separation unit (14).

15. Use of a pre-filter arrangement (18) in DAC systems (10) to increase the service life of system components used in a DAC system (10) by prior treatment of the ambient air (12) supplied to the CO2 separation units (14), wherein the pre-filter arrangement (18) comprises: I) a particle filter element (20) for separating particulate contaminants from the ambient air (12), and II) an adsorption element (22) comprising a porous adsorption material for the physical and / or chemical adsorption of one or more gaseous pollutants from the ambient air (12), wherein the gaseous pollutants are selected from the group consisting of ammonia, ozone, hydrogen sulfide, sulfur oxides, nitrogen oxides and volatile organic compounds, which have a vapor pressure of 0.01 kPa or more at 20 °C. - 33 - 16. Pre-filter arrangement (18) for use in DAC systems (10), in particular DAC system (10) according to any one of claims 1 to 13, wherein the pre-filter arrangement comprises (18): I) a particle filter element (20) for separating particulate contaminants from the ambient air (12), comprising a filter medium and II) an adsorption element (22) comprising a porous adsorption material for the physical and / or chemical adsorption of one or more gaseous pollutants from the ambient air (12), wherein the gaseous pollutants are selected from the group consisting of ammonia, ozone, hydrogen sulfide, sulfur oxides, nitrogen oxides and volatile organic compounds, which have a vapor pressure of 0.01 kPa or more at 20 °C, wherein the pre-filter arrangement (18) is preferably designed to allow air to be filtered to pass through the particle filter element (20) and the adsorption element (22).

17. Pre-filter insert for a pre-filter arrangement (18) according to claim 16 for use in DAC systems (10), comprising integrating into the pre-filter insert: I) a particle filter element (20) for separating particulate contaminants from the ambient air (12), comprising a filter medium and II) an adsorption element (22) comprising a porous adsorption material for the physical and / or chemical adsorption of one or more gaseous pollutants from the ambient air (12), wherein the gaseous pollutants are selected from the group consisting of ammonia, ozone, hydrogen sulfide, sulfur oxides, nitrogen oxides and volatile organic compounds, which have a vapor pressure of 0.01 kPa or more at 20 °C, wherein the pre-filter insert is preferably designed to allow air to be filtered to pass through the particle filter element (20) and the adsorption element (22).

Images