DE102024107282A1 - Zeolitic shaped body, process for its preparation and its use as a sorption element - Google Patents

Abstract

The invention relates to zeolitic molded bodies (10, 70, 80) based on a zeolite material (36) and a binder (38). The molded body has macropores and/or nano/microchannels that impart additional porosity to the molded bodies. The invention also relates to a method for producing the molded bodies (10, 70, 80), wherein pore formers (40) based on organic materials are used to obtain additional porosity in the molded bodies (10, 70, 80) after a thermal treatment.

Description

The invention relates to shaped bodies based on zeolites, in particular those with a faujasite structure. Furthermore, the invention relates to a process for producing a shaped body based on zeolites for use as a sorption element in adsorption processes, in particular for separating carbon dioxide from the ambient air.

Direct Air Capture (DAC) is a process for extracting carbon dioxide ( _CO2 ) directly from the ambient air. The basic principle is that ambient air flows through a filter which removes some of the _CO2 . The result of the process is pure _CO2 , which can then be used for various purposes. Possible uses of _CO2 include its use as a raw material, for example in the chemical industry, the production of _CO2 -neutral fuels (renewable gas and e-fuels), and the geological storage of carbon dioxide, which can result in negative emissions. The latter is known as Direct Air Carbon Capture and Storage (DACCS) and is intended to actively remove carbon dioxide from the atmosphere and permanently store it using _CO2 capture and storage (CCS) in order to counteract global warming.

Most known processes for separating carbon dioxide from ambient air employ a cyclic process using a combination of pressure and temperature changes. In a first process step, carbon dioxide present in the atmospheric air is bound in a sorption element, thereby reducing the carbon dioxide content in the atmospheric air. The carbon dioxide bound in the sorption element can be released again in a second process step and either stored or fed into another process in which the released carbon dioxide is required as a feedstock. The development of suitable adsorption materials and their technical implementation in appropriate adsorption systems should enable efficient and energetically effective carbon dioxide capture.

One challenge is the development of efficient adsorption systems in which the sorption elements are technically arranged and/or designed in such a way that, on the one hand, the adsorption and desorption of carbon dioxide takes place optimally and, on the other hand, a comparatively cost-effective plant concept can be implemented. The heating and cooling phases in particular influence the process costs, while the design of the sorption element and the process chamber influence the plant costs. Inorganic sorption materials, also called physisorbents, are particularly well suited as adsorbers for the capture of carbon dioxide due to their robustness. However, such inorganic sorption materials have comparatively long heating and cooling phases between the adsorption and the subsequent desorption of the carbon dioxide, thus leading to reduced effectiveness and increased energy consumption. Furthermore, the mechanical structures that hold the adsorption materials require a lot of material, which leads to high plant costs.

The core of a DAC system is therefore the sorption element, which has the task of first capturing and binding the carbon from the ambient air in a so-called adsorption process and then releasing the captured amount from the sorption element in a precise and controlled manner (desorption).

There are now a number of materials that are capable of absorbing _CO2 within a DAC system. However, these materials either absorb relatively high _CO2 concentrations, in which case desorption is energy-intensive, or the selective binding of _CO2 to the adsorber is not very high, in which case the overall efficiency is low and the costs for _CO2 reduction are high.

In the disclosure document DE 2 016 838 For example, a process is described for the production of granulated, abrasion-resistant, binder-free molecular sieve zeolites consisting of a powdered faujasite zeolite and a type A zeolite.

The DE 10 2008 046 155 A1 describes a process for producing adsorbent granules based on zeolites with a faujasite structure, wherein the type X zeolite with a molar SiO ₂ /Al ₂ O ₃ ratio of 2.25 to 2.5 is mixed as a dry powder, filter cake or slurry in a weight ratio of 1:1 to 5:1 with a thermally treated kaolin having an average particle diameter in the range of < 10 µm. This mixture is mixed with a mixture of sodium hydroxide solution and sodium silicate solution, which in turn is then formed into granules. The granules are dried and then rinsed with demineralized water and treated with a sodium aluminate solution at temperatures in the range of 70°C to 90°C for a period of 8 to 24 hours. The treated granules are then separated from the solution, washed, dried and tempered.

In the patent specification US$4,818,508 A process for producing zeolite-type molecular sieves is disclosed, but the use of a pore former such as kaolin-based clay is described here in order to ensure the most complete conversion possible for the production of binder-free zeolite materials.

From the DE 699 17 041 T2 and the EP 0 940 174 A2 Adsorption materials are known that have a SiO ₂ / Al ₂ O ₃ ratio in the range of 1.8 to 2.2 or 1.9 to 2.1. These are zeolites with a low silicon dioxide content.

In the DE 30 11 834 A1 A process for the production of finely divided, zeolitic sodium aluminum silicates is described, in which steam is introduced during a discontinuous crystallization and simultaneously stirred with multi-stage high-shear agitators.

In the patent specification US$3,516,786 A process is described that produces particularly small particles by adding 0.1 to 20% of an organic solvent, such as methanol or dimethyl sulfoxide, to an aluminum silicate gel prior to crystallization. Due to the toxicity of these solvents, the processing of the process liquors requires special precautions.

Molecular sieve adsorbents with improved adsorption capacities, particularly for the removal of carbon dioxide from gas mixtures, are also known from the prior art. For example, the patent specification US$2,882,244 a variety of crystalline aluminum silicates suitable for CO ₂ adsorption. The patent US 3,078,639 describes a zeolite X that can be used to adsorb carbon dioxide from a gas stream. The patent US$3,865,924 describes a carbon dioxide adsorbent consisting of a mechanical mixture of activated aluminum oxide and alkali metal carbonates. From the patent US$4,433,981 An adsorbent is known which is produced by impregnating aluminum oxide with an alkali or alkaline earth metal oxide or salt which can be decomposed upon calcination. The patent specification US$4,493,715 describes an adsorbent for the removal of carbon dioxide from olefins containing alkali metal oxides, hydroxides, nitrates, acetates, etc., supported on activated alumina.

However, the adsorbents described in the prior art exhibit low operational reliability and a short service life due to the tendency of the active components to sinter. Furthermore, the time to water breakthrough in the previously known adsorbents is shorter than the time to carbon dioxide breakthrough. This is solved in the prior art by additional dewatering beds. Furthermore, base-containing adsorbents cannot be used in pressure swing adsorbent (PSA-type) units because they form compounds with _CO2 that cannot be regenerated at reduced pressure.

Sorption elements that bind via physiosorption are generally particularly sensitive to moisture. This means that the sorption element is capable of absorbing residual moisture from the dried air into the porous microstructure, which directly leads to a reduction in _CO2 absorption capacity. This results in the process becoming less efficient, as a much lower _CO2 yield can be achieved with the same energy consumption. This effect can be counteracted, for example, by introducing regeneration of the sorption elements into the process, which, however, worsens the energy balance.

Typically, the sorption element is heated to the desired temperature using heat exchangers. However, since the existing sorption elements have very poor thermal conductivity, this has a negative impact on energy costs, especially during desorption. Overall, the processes used to date are associated with high energy costs. The sorption elements used to date also show room for improvement in terms of their strength with respect to operating cycles in order to increase the material's durability.

There is therefore still a need for efficient molded bodies used as sorption elements and suitable for adsorption and desorption, particularly for _CO2 , in order to further optimize DAC technology for the production of _CO2 for e-fuel production and reduce production costs. The focus is particularly on the development of efficient sorption elements that allow for reproducible adsorption and desorption of carbon dioxide with lower energy consumption and, on the other hand, a comparatively cost-effective plant concept.

In particular, the heating and cooling phases and also the regeneration influence the process costs.

The invention is based on the object of separating carbon dioxide from the ambient air in a comparatively simple and cost-effective manner and of to overcome known disadvantages of the state of the art.

This object is achieved in the present invention, first of all, by the features of patent claim 1. It is provided that shaped bodies are provided that are based on a zeolite material and a binder. The shaped bodies according to the invention have i) macropores with a diameter of greater than 200 nm, measured, for example, by means of high-pressure mercury porosimetry, or ii) channels with a length of greater than 300 nm, measured, for example, by means of optical microscopy, SEM, TEM, or CT, preferably optical microscopy, or iii) a combination of i) and ii).

• - Bereitstellung eines Zeolith-Materials, eines Bindemittels und eines Porenbildners, wobei der Porenbildner ausgewählt ist aus der Gruppe bestehend aus
  1. a) organischen Pulvern mit einer Teilchenverteilung von 5 bis 2000 µm,
  2. b) organischen Fasermaterialien mit einer Teilchenverteilung von 5 bis 2000 µm,
  3. c) Lösungen oder Gele polymerer Materialien
• - Vermischen des Zeolith-Materials mit dem Bindemittel und dem Porenbildner, gegebenenfalls unter Zugabe von Wasser, zu einem formbaren Stoffgemisch,
• - Verarbeitung des formbaren Stoffgemischs zu einem Formkörper,
• - Trocknen und Calcinieren des.

The above object is further achieved by a process for producing a zeolitic shaped body, comprising

• - Providing a zeolite material, a binder and a pore former, wherein the pore former is selected from the group consisting of
  1. a) organic powders with a particle distribution of 5 to 2000 µm,
  2. b) organic fibre materials with a particle distribution of 5 to 2000 µm,
  3. c) Solutions or gels of polymeric materials
• - Mixing the zeolite material with the binder and the pore former, if necessary with the addition of water, to form a moldable mixture,
• - processing the moldable mixture into a molded body,
• - Drying and calcining the.

The macropores of the molded body have a diameter of at least 200 nm, preferably a diameter in the range of 500 nm to 500 µm, particularly preferably in the range of 1000 nm to 300 µm. The diameter of the macropores is an average diameter that is volume-related.

The channels of the shaped body have a length of at least 300 nm, preferably a length in the range of 500 nm to 1000 µm, particularly preferably in the range of 1000 nm to 800 µm. The length of the channels is an average length.

Exemplary embodiments of the zeolite material are zeolites with a faujasite or Linde type A structure, such as 3A, 4A, 5A, or mixtures of both zeolite types. Zeolites with a faujasite structure are preferred. Zeolite type 13X is particularly preferred.

Exemplary embodiments of the binder are mineral or synthetic materials, such as clay (e.g., kaolinite, bentonite, montmorillonite, attapulgite), silicon dioxide, aluminum oxide, aluminum hydrate (pseudoboehmite), aluminum trihydrate, aluminosilicate, cement, or other comparable materials. Bentonite is preferred.

Suitable pore formers are, for example, a) organic powders with a particle distribution of 5 to 2000 µm, b) organic fiber materials with a particle distribution of 5 to 2000 µm, or c) solutions or gels of polymeric materials or mixtures thereof. Preferred a) organic powders are selected from tannin, polyester, polypropylene, polyvinyl chloride, acrylonitrile-butadiene-styrene, or cellulose-based natural materials, with particular preference being given to tannin. Preferred b) organic fiber materials are selected from plant fibers, such as cotton, jute, flax, hemp, or tannin, or animal fibers, such as wool, hair, or feathers, with particular preference being given to flax. The length of the organic fiber materials is preferably 200 µm to 3 mm. Preferred c) solutions or gels of polymeric materials are selected from the group consisting of carboxymethylcellulose, polyvinyl alcohols, polyethylene glycols, polyacrylamides, or polyacrylic acid copolymers.

By using the pore formers in the process according to the invention, zeolitic shaped bodies are obtained which have i) macropores with an average diameter of greater than 200 nm, preferably 1000 nm to 300 µm, or ii) channels or depressions with a length of greater than 300 nm, preferably 1000 nm to 800 µm, or a combination of i) and ii).

The sum of the i) macropores and/or ii) channels or depressions is referred to as secondary porosity within the meaning of the present invention. In addition to secondary porosity, the zeolitic molded bodies of the present invention also exhibit primary porosity, which is determined by mesopores with an average diameter of 2 to 50 nm. The macropores and nano- or µ-channels serve to improve (e.g., increase) effectiveness, particularly in dynamic adsorption and desorption processes. The presence of the macropores and/or channels enormously increases the contact area of the molded body, thus enabling better gas or air exchange with the sorption material. The i) macropores and ii) channels are preferably present as a combination (mixture) in the molded bodies according to the invention.

The shaped body according to the invention thus enables improved adsorption capacity. At the same time, the shaped bodies according to the invention exhibit good adsorption performance at room temperatures and low partial pressures. Overall, the use of the shaped bodies according to the invention as sorption elements allows the overall costs (e.g., plant costs, process time) for _CO2 production to be reduced by shorter desorption and regeneration times. Furthermore, the shaped bodies according to the invention exhibit improved adsorption kinetics and adsorption dynamics for both temperature swing processes and positive and negative pressure swing processes, or combinations of these processes.

Further preferred embodiments of the invention emerge from the remaining features mentioned in the subclaims.

In an advantageous embodiment of the shaped bodies, it is provided that the zeolite material is X-zeolite with a SiO ₂ /Al ₂ O ₃ ratio of less than 3.0, preferably the 13X zeolite type with a low silicon dioxide content with a SiO ₂ /Al ₂ O ₃ ratio of 1.8 to 2.5, preferably 1.8 to 2.1, particularly preferably 1.8 to 2.0.

By using a zeolite material with a faujasite structure and a molar SiO ₂ /Al ₂ O ₃ ratio of 1.8 to 2.5, a molded body can be produced that exhibits an optimal transport pore system and a maximum content of active zeolite material with a faujasite structure. It has also been shown that the carbon dioxide adsorption capacity of the low-silica Faujasite X zeolite type is significantly higher.

In an advantageous embodiment of the shaped body, it is provided that it additionally comprises one or more inorganic additives or reinforcing materials, selected from inorganic powders with a particle distribution of 1 to 1000 µm, inorganic fibers with a particle distribution of 1 to 5000 µm, metal splinters with a particle distribution of 10 to 2000 µm, or a combination. Preference is given to inorganic fibers with a length of 200 µm to 50 mm, particularly preferably from 200 µm to 3 mm. Exemplary powders include: calcium silicate, aluminum oxides (α-Al ₂ O ₃ , γ-Al ₂ O ₃ , η-Al ₂ O ₃ , and δ-Al ₂ O ₃ ) with a particle distribution such as from 1 to 1000 µm.

Suitable fibers include amorphous fibers (glass fibers, rock wool), polycrystalline fibers (aluminum fibers, carbon fibers), or monocrystalline fibers (wollastonite) with a particle size distribution of 1 to 1500 µm. Glass fibers with a length of 1 to 4 mm are preferred. Examples of metal splinters include sawdust made of aluminum, iron, copper, or other metals with a particle size distribution of 10 to 2000 µm.

In an advantageous embodiment of the shaped bodies, it is provided that the shaped bodies are present as compact shaped bodies in the form of a plate, a tube, a square honeycomb, a triangular honeycomb or a hexagonal honeycomb.

Zeolitic shaped bodies in the form of a plate, a tube, a solid cylinder or as a honeycomb structure (for example square honeycomb, hexagonal honeycomb, triangular honeycomb) are, for example, compact shaped bodies that are used as such.

In an alternative embodiment, the zeolitic shaped bodies are present, for example, as granules, irregular particles, spheres, beads, cylinders, pellets, rings, or extrudates (such as extruded pellets or extruded sleeves). These are preferably in the form of a bed of a plurality of bodies, which collectively exhibit the properties of a bed.

If the molded bodies are in a compact form such as a plate, tube, solid cylinder, or honeycomb structure, they exhibit a high volumetric fill rate while simultaneously offering comparatively excellent flow throughput, as is the case, for example, with a honeycomb shape with wide webs and narrow channels. Due to the higher volumetric fill rate of the molded bodies formed in this way (more active material per volume), the effectiveness of the corresponding processes is increased.

In an advantageous embodiment of the method for producing the shaped bodies, it is provided that one or more inorganic additives or reinforcing materials selected from the group consisting of d) inorganic powders with a particle distribution of 1 to 1000 µm, e) inorganic fibers with a particle distribution of 1 to 5000 µm or f) metal splinters with a particle distribution of 10 to 2000 µm are additionally added to the moldable substance mixture.

The above-mentioned inorganic additives serve to reinforce or strengthen the sorption material, thereby increasing its operational durability. In particular, they can increase the strength and functionality of 3D compact molds, which can be attributed to a reduction in abrasion during operation. The molded bodies reinforced in this way therefore have not only a high _CO2 adsorption capacity but also increased material strength. They are therefore robust under cyclic process stress. faster and reproducible, which in turn has a positive effect on quality and process costs.

In a further advantageous embodiment of the method, the processing of the moldable mixture of materials comprises coating at least one surface side, preferably both surface sides, of a base molded body, which is preferably a plate-shaped molded body, with the moldable mixture of materials. The base molded body preferably comprises a zeolite material and a binder; particularly preferably, the base molded body additionally comprises one or more inorganic additives or reinforcing materials. The base molded body itself preferably has no secondary porosity. The coating of the base molded body based on the moldable mixture of materials imparts the selective porosity to the molded body thus produced.

This results in a molded body that selectively exhibits secondary porosity on its surrounding surface. Secondary porosity represents the sum of the pores and/or channels that connect the inner basic structure of the molded body to the surrounding medium or air. This enables efficient exchange, especially during dynamic processes (adsorption, desorption, and regeneration).

In a further advantageous embodiment of the method, the processing comprises applying a film to one surface side of a base molded body, which is preferably a plate-shaped molded body, with the moldable material mixture. The film is, for example, a composite material comprising a carrier material and the moldable material mixture. Preferably, the carrier material used is a material that is almost completely thermally degraded upon calcination. Particularly preferably, the carrier material is a polymer matrix.

By using a film, one side of the molded body can be selectively provided with a specific amount of moldable material mixture and allows the separate production of the base molded body and the film.

A further aspect is the use of the zeolitic shaped bodies described in the preceding sections as sorption elements in technical adsorption processes, in particular for the adsorption or desorption of _CO2 or _H2O , preferably in the DAC process. However, use is also possible in all technical fields where, for example, gas separation, gas purification, or gas dehumidification is carried out.

The various embodiments of the invention mentioned in this application can be advantageously combined with one another, unless otherwise stated in the individual case.

• 1a, 1b zwei mögliche Anlagen zur Abtrennung von Kohlenstoffdioxid aus der Umgebungsluft,
• 2a eine bekannte Kristallstruktur eines Adsorptionsmaterials auf Basis eines Faujasit-Zeoliths 13X,
• 2b eine bekannte Kristallstruktur eines Adsorptionsmaterials auf Basis eines Faujasit-Zeoliths 13X mit Mesoporen ,
• 2c eine konkrete Ausführungsform der Kristallstruktur der erfindungsgemäßen Formkörper,
• 3a eine vereinfachte Darstellung eines erfindungsgemäßen Formkörpers als Sphären-Granulat mit sekundärer Porosität,
• 3b eine vereinfachte Darstellung eines erfindungsgemäßen Formkörpers als Sphären-Granulat mit sekundärer Porosität und mit anorganischen Fasern,
• 4a verschiedene Ausführungsformen möglicher Herstellungsformen der erfindungsgemäßen zeolithischen Formkörper als Schüttung,
• 4b verschiedene Ausführungsformen möglicher Herstellungsformen der erfindungsgemäßen zeolithischen Formkörper als kompakte Formkörper,
• 5 ein erstes Ablaufdiagramm zur Durchführung eines erfindungsgemäßen Verfahrens zur Herstellung eines zeolithischen Formkörpers zur Abtrennung von Kohlenstoffdioxid aus der Umgebungsluft,
• 6 ein zweites Ablaufdiagramm zur Durchführung eines erfindungsgemäßen Verfahrens zur Herstellung einer konkreten Ausführungsform der erfindungsgemäßen zeolithischen Formkörper,
• 7 ein drittes Ablaufdiagramm zur Durchführung eines erfindungsgemäßen Verfahrens zur Herstellung einer weiteren konkreten Ausführungsform der erfindungsgemäßen zeolithischen Formkörper.

The invention is explained below in exemplary embodiments with reference to the accompanying drawings. They show:

• 1a , 1b two possible plants for separating carbon dioxide from the ambient air,
• 2a a known crystal structure of an adsorption material based on a faujasite zeolite 13X,
• 2b a known crystal structure of an adsorption material based on a faujasite zeolite 13X with mesopores,
• 2c a concrete embodiment of the crystal structure of the shaped bodies according to the invention,
• 3a a simplified representation of a shaped body according to the invention as spherical granulate with secondary porosity,
• 3b a simplified representation of a molded body according to the invention as spherical granulate with secondary porosity and with inorganic fibers,
• 4a various embodiments of possible production forms of the zeolitic shaped bodies according to the invention as a bed,
• 4b various embodiments of possible production forms of the zeolitic shaped bodies according to the invention as compact shaped bodies,
• 5 a first flow diagram for carrying out a process according to the invention for producing a zeolitic shaped body for separating carbon dioxide from the ambient air,
• 6 a second flow diagram for carrying out a process according to the invention for producing a specific embodiment of the zeolitic shaped bodies according to the invention,
• 7 a third flow diagram for carrying out a process according to the invention for producing a further concrete embodiment of the zeolitic shaped bodies according to the invention.

The 1a and 1b each show a schematic representation of two embodiments of a system 100 and 110 for separating carbon dioxide from ambient air.

1a shows a system 100 comprising two process chambers 11 and 12. Process chamber 11 is provided as a drying stage, where gas is dehumidified. Adsorption/desorption takes place in process chamber 12. Both chambers 11 and 12 contain the shaped bodies according to the invention as sorption elements 14, 15, which are responsible for drying or adsorbing gases. The process chambers 11 and 12 are technically connected to each other by various lines, flaps, valves 13, etc. After desorption, the collected gas is technically forwarded to the main storage unit 17 via the line fitting 16.

1b shows a system 110 comprising only the process chamber 12. Process chamber 12 serves for adsorption/desorption, eliminating the need for a separate drying stage. The molded bodies according to the invention, as sorption elements 15, are installed accordingly in the chamber 12, for example, they are installed horizontally or vertically. The process chamber 15 is technically connected by various lines, flaps, valves 13, etc. After desorption, the collected gas is technically forwarded to the main storage unit 18.

2a shows a crystal structure 20 of an adsorption material based on a faujasite zeolite 13X with a diameter of 1.8 to 2 mm and a so-called faujasite pore system 22, which has a pore size of, for example, 7.4Å and whose pores are arranged in a crossing manner.

2b is a detailed representation of the crystal structure 20 known from the prior art. When the crystal structure 20 comes into contact with ambient air, the partial pressure at the surface of the sorption material increases. The _CO2 molecules 23 from the air pass through the porous intermediate channels 24 into the crystal pore system 22. There, the _CO2 molecules 23 are bound via an interaction with Na ⁺ cations 26 (adsorption). The intermediate channels 24, or mesopores, represent the primary porosity of the adsorbent and are responsible for the adsorption of _CO2 molecules 23 on the entire surface. However, the intermediate channels 24 can be partially or completely occupied with _H2O molecules from the air and thus closed. It is also possible that free intermediate channels 24 are occupied by residual moisture after drying, which greatly reduces _CO2 adsorption or no longer has a good absorption capacity.

In 2c A specific embodiment of the crystal structure 21 of the molded bodies according to the invention is shown. The crystal structure 21 comprises a further secondary porosity 25, which expands (widens) the existing intermediate channels 24 of the primary porosity and connects the two pore systems. This supports, for example, desorption and adsorbent regeneration and thus enables more efficient, complete, and reproducible processes. The integration (incorporation) of the secondary porosity 25 can be produced in different ways and is explained in the further figures. For example, secondary porosity can be adjusted accordingly by the binder composition. Another possibility for forming the secondary porosity in the crystal structure 21 is by adding pore formers selected from the group consisting of a) organic powders with a particle distribution of 5 to 2000 µm, b) organic fiber materials with a particle distribution of 5 to 2000 µm, or c) solutions or gels of polymeric materials or mixtures thereof. The pore-forming agents are preferably selected such that they are completely thermally degraded from the crystal structure 21 of the zeolite during calcination at a temperature of 350°C to 800°C, preferably from 400°C to 650°C, particularly preferably from 450°C to 550°C, in particular at 500°C. During the thermal treatment, the organic constituents are degraded or decomposed and thus removed in gaseous form from the sorption material. The crystal structure 21 of the shaped bodies according to the invention has not only primary but also secondary porosity. The shaped bodies produced in this way have high _CO2 adsorption and increased material strength, making them more robust and reproducible (suitable for series production) under cyclic process stress, which in turn has a positive influence on quality and process costs.

3a shows a simplified representation of a spherical granulate 30, the structure 31 of which comprises not only a primary porosity 32 but also a secondary porosity 33. The shaped bodies according to the invention have macropores 33 with a diameter of greater than 200 nm as a transport pore system. The macropores of the shaped body have a diameter of at least 200 nm, preferably a diameter in the range from 500 nm to 500 µm, particularly preferably in the range from 1000 nm to 300 µm. The diameter of the macropores is an average diameter that is volume-related. For example, with a dB90<500 nm, 90% of the pores are smaller than 500 nm. A shaped body with a volume of 1 ^dm3 , for example, has pores after calcination that are distributed throughout the volume of the shaped body. For example, with a proportion of 2 wt% of pore formers that decompose during calcination, a total pore volume of approximately 2% per ^1dm3 is achieved, which is divided into the pore sizes.

Alternatively or additionally, the shaped bodies according to the invention have nano- or μ-channels with a length greater than 300 nm. The channels of the shaped body have a length of at least 300 nm, preferably a length in the range of 500 nm to 1000 μm, particularly preferably in the range of 1000 nm to 800 μm. The length of the channels is an average length. The macropores 33 and/or channels increase the effectiveness, particularly in dynamic adsorption and desorption processes.

3b shows a simplified representation of a spherical granulate 30, whose structure 31 comprises, in addition to a primary porosity 32, a secondary porosity 33, as well as inorganic additives or reinforcing materials 34, depicted here as fibers, which serve, for example, for reinforcement. This achieves, for example, not only increased effectiveness, especially in dynamic adsorption and desorption processes, but also a higher strength of the material structure 31.

In 4a Various embodiments of possible shapes 40 of the zeolitic shaped bodies 10 according to the invention are shown as a bed, such as granules in the form of spheres 42, irregular particles 44, extruded pellets 46 and extruded sleeves 48. The diameter d of the spherical granules 42 or the extruded pellets 46 is preferably between 0.3 and 8 mm. In the case of rectangular, triangular or hexagonal extrudates 46, the edge lengths (a, b, c) are preferably between 0.3 and 5 mm. Extruded sleeves 48 are, for example, round, rectangular, triangular or hexagonal in their cross-section d and have, for example, a diameter of preferably 0.3 to 5 mm and edge lengths (a, b, c) of preferably 0.3 to 5 mm. The inner cavity of the extruded sleeves 48 has a diameter d of preferably 0.3 to 5 mm.

4b shows embodiments of the zeolitic shaped bodies 10 according to the invention as compact shaped bodies, such as, for example, a plate 52, a tube or multi-channel tube 54, a square honeycomb 46 with various lengths, as well as various other cross-sections such as a triangular honeycomb or hexagonal honeycomb 58 with different channel width/web width ratios. The compact shaped bodies according to the invention contain a maximum amount of zeolite material per volume, thick walls, and low porosity, which enables high capacity and good mechanical properties. The compact shaped bodies have, for example, a space filling of >85%, whereas, for example, the space filling of the sphere bed is 74%. The bulk density of spheres is, for example, between 600 kg/m ³ and 1000 kg/m ³ .

In 5 A first example of a method according to the invention for producing a zeolitic shaped body 10 for a plant 100 or 110 is shown. The method comprises the provision <100> of a carbon dioxide-binding zeolite material 36, which is preferably designed as a zeolite material with a faujasite structure and a molar SiO ₂ /Al ₂ O ₃ ratio of 1.8 to 2.5, and the provision of a binder 38. The zeolite material 36 and the binder 38 as well as one or more pore formers 39 are mixed in a method step <110> to form a moldable material mixture 73, wherein the aim is to achieve the most homogeneous mixing possible of the components 36, 38, 40. Preferably, one or more inorganic additives or reinforcing materials 34, preferably fibers, are additionally added to the material mixture 73. In a subsequent process step <120>, a shaped body is produced, which may include, in particular, extrusion, granulation, powder injection molding, injection molding, and other process steps. In a subsequent process step <130>, the shaped bodies can be dried. Drying is followed by a heat treatment <140>, which, in particular, includes a sintering process for the cohesive bonding of the substance mixture 73, thus obtaining the shaped body 10 according to the invention.

6 shows a second flow diagram for carrying out a method according to the invention for producing a specific embodiment of the zeolitic shaped body 70 according to the invention in the form of a plate-shaped zeolitic shaped body with secondary porosity on both sides. In the production of the zeolitic shaped body 70, a base shaped body 71, preferably designed as a plate-shaped shaped body, is first provided. The base shaped body 71 contains a base material mixture comprising a zeolite material 36 and a binder 38. It is also possible for the base material mixture to additionally contain one or more inorganic additives or reinforcing materials 34, preferably fibers. The base shaped body 71 is produced in step <200> and has a material thickness d of, for example, 1 mm to 20 mm, preferably 3 mm to 8 mm, particularly preferably 4 mm to 6 mm. The base shaped body 71 is produced, for example, by various manufacturing processes, with semi-wet pressing or casting being preferred. Also suitable for step <200> are processes that can process pasty masses. The base molded body 71 thus produced is covered on both surface sides 72 by means of a bulk powder mixture 73 in step <210> or coated with a Bulk powder mixture 73 is sprinkled. The bulk powder mixture 73 comprises the zeolite material 36 and the binder 38 (forming the base material mixture) as well as one or more pore formers 39. The bulk powder mixture 73 preferably also contains one or more inorganic additives or reinforcing materials 34, particularly preferred being fibers. The ratio of the base material mixture of the base molded body 71 to the bulk powder mixture 73 is, for example, in vol%: 10% to 95% or 95% to 10%, whereby the composition of the bulk powder mixture 73 can also have very wide variations in its own proportions. The task of the bulk powder mixture 73 is to distribute itself homogeneously on the semi-wet surface side 72 of the plate and to bond with the material of the base molded body 71 by applying force over the entire surface. In step <220>, for example, a pressing process takes place, through which the molded body 70 can achieve a desired thickness. The bulk powder mixture 73 is preferably pressed onto the surface 72, allowing various thicknesses to be created. After the calcination process (heat treatment) (<230>), a slight, controlled volume shrinkage occurs. The bulk powder mixture 73 is thus completely combined with the material of the base molded body 71 through the calcination process (virtually pre-sintered), and the compact, plate-shaped molded body 70 according to the invention is created. Furthermore, the pore-forming agents 39 of the bulk powder mixture 73 are completely thermally degraded at higher temperatures. The result is the formation of a secondary porosity 74, which is mapped in a controlled manner onto the surface of the molded body 70. The secondary porosity 74 represents the sum of numerous macropores and/or channels that connect the inner basic structure 75 of the molded body 70 with the ambient medium 76 or with air. This enables efficient exchange, particularly during dynamic processes (adsorption, desorption, and regeneration). A further advantage of the molded bodies 70 according to the invention is that proportions (e.g., in wt. %) of the bulk powder mixture 73 and its powder particle distribution can be very broadly combined with the base material mixture of the base molded body 71 (e.g., in wt. %) and its powder particle distribution. As a result, after thermal decomposition of the pore formers 39 during calcination (<230>), different forms of pore openings can be formed on the surface, such as macropores with a diameter of greater than 200 nm, preferably 1000 nm to 300 µm and/or nano- or µ-channels with a length of greater than 300 nm, preferably 1000 nm to 800 µm, or nano- or µ-depressions, which then enormously increase the contact area of the shaped body and thus enable better gas or air exchange with the adsorbent material.

In a further embodiment, the bulk powder mixture 73 contains one or more inorganic fibers or reinforcing materials 34, preferably inorganic fibers. These are thermally stable and do not undergo any changes during calcination, thus contributing, for example, to increasing the strength of the surface (reinforcement). A simplified schematic representation is shown in detail "D" of the 6 visible.

7 shows a third flow diagram for carrying out a method according to the invention for producing a further specific embodiment of the zeolitic molded body 80 according to the invention in the form of a plate-shaped zeolitic molded body with one-sided secondary porosity. During the production of the molded body 80, for example, a film 81 is applied along the surface side 82 of the base molded body 83, which contains a base material mixture of zeolite material 36 and binder 38, and pressed (<300>). The film 81 is preferably a composite material made of a carrier material and a mixture of substances that has the same or similar composition as the bulk powder mixture 73, wherein the powder mixture has been applied to a carrier. A suitable carrier material, for example, is a polymer matrix that has the function of holding the powder charge during handling (<310>). After pressing into the base molded body 83 during calcination (<320>), the foil 81 disappears completely from the structure of the resulting molded body 80. The position “D” of the 7 shows a schematic representation of the final state, wherein in this embodiment of the molded body 80, only one surface side 82 has an extremely enlarged surface structure with the secondary porosity 84, which enables better exchange upon contact with gas or the ambient medium 86 (air). The secondary porosity 84 represents the sum of numerous macropores and/or channels that connect the inner basic structure 85 of the molded body 70 with the ambient medium 86 or with air.

In a further embodiment, the film 81 contains one or more inorganic fibers or reinforcing materials 87, preferably inorganic fibers that are thermally stable and that do not undergo any changes during calcination but remain unchanged and can thus contribute to increasing the strength of the surface (reinforcement).

Examples

Example 1

Example 1 describes the production of a molded body based on a base material mixture

A tablet mixture consisting of 80 wt% zeolite material and 20 wt% bentonite is prepared. 30 wt% water is added to the mixture to create a mass with the appropriate consistency. This mass is then transferred to a mold, where it is compressed to a weight of 25,000 kg. The compressed form is then removed from the mold and heat-treated at a temperature of 500 °C.

Example 2

Example 2 describes the production of a zeolitic shaped body according to the invention with improved porosity

A base material mixture is produced in compressed form, consisting of 80 wt% zeolite material and 20 wt% bentonite. 30 wt% water is added to the mixture to produce a mass with the appropriate consistency. A shakeable powder mixture is then produced consisting of 78 wt% zeolite material, 19 wt% bentonite, 2 wt% flax fiber, and 1 wt% tannin. 30 wt% water is added to produce a mass with the appropriate consistency. 50 wt% of the total mass of the shakeable powder mixture is then filled into the mold and compressed with a weight of 25,000 kg. The base material mixture is then applied in a single layer onto the pressed porous mass. The mass is then pressed again with a weight of 25,000 kg. 50 wt% of the total mass of the shakeable powder mixture is then again introduced into the mold in a single layer and compressed with a weight of 25,000 kg. The pressed form is then removed from the mold and heat-treated at a temperature of 500 degrees Celsius. Organic particles from the porous mass are combusted in the air stream, leaving channels and cavities (secondary porosity) in the molded body.

Example 3

Example 3 describes the production of a zeolitic shaped body according to the invention with improved porosity and improved mechanical stability

A compressed base material mixture is prepared, consisting of 80 wt% zeolite material, 19.5 wt% bentonite, and 0.5 wt% glass fibers measuring 1-4 mm in length. 30 wt% water is added to the mixture to produce a mass of the appropriate consistency.

A shakeable powder mixture is then prepared from 78 wt% zeolite material, 18.5 wt% bentonite, 2 wt% flax fibers 1-2 mm long, 1 wt% tannin, and 0.5 wt% glass fibers 1-4 mm long. 30 wt% water is added to the mixture to produce a mass of the appropriate consistency.

Subsequently, 50 wt% of the total mass of the porous mixture is poured into the mold and compressed with a weight of 25,000 kg. The base material mixture is then applied in a single layer to the pressed porous mass. The mass is then pressed again with a weight of 25,000 kg. After that, 50 wt% of the total mass of the porous mixture is again introduced into the mold in a single layer and compressed with a weight of 25,000 kg.

The molded body is then removed from the mold and heat-treated at a temperature of 500 °C. Organic particles from the porous mass are combusted in the air stream, leaving channels and cavities that reduce the diffusion restrictions for adsorbate molecules. Glass fibers reinforce the structure as microreinforcements, thus increasing the mechanical stability of the molded bodies.

List of reference symbols

10

zeolitic molded body

11, 12

Trial Chamber

13

Pipes, flaps, valves

14, 15

sorption element

16

Pipe fitting

17, 18

Main memory

20

Crystal structure of faujasite zeolite 13X

21

Crystal structure of the molded body according to the invention

22

Faujasite pore system

23

_CO2 molecules

24

Intermediate channels

25

secondary porosity

26

Na ⁺ cations

30

Spherical granules

31

structure

32

primary porosity

33

secondary porosity

34

inorganic additives or reinforcing materials

39

Pore formers

40

Shapes of the zeolitic shaped bodies according to the invention

42

Granules as spheres

44

irregular particle

46

extruded pellets

48

extruded sleeves

50

compact forms of the zeolitic shaped bodies according to the invention

52

plate

54

Multi-channel pipe

56

Square honeycomb

58

various cross-sections

70

plate-shaped zeolitic molded body with secondary porosity on both sides

71

Basic molded body

72

Surface side

73

moldable mixture of substances

74

secondary porosity

75

internal basic structure

76

ambient medium

80

plate-shaped zeolitic body with one-sided secondary porosity

81

film

82

Surface side

83

Basic molded body

84

secondary porosity

85

internal basic structure

86

ambient medium

87

inorganic additives or reinforcing materials

100

Direct air capture system

110

Direct air capture system

QUOTES CONTAINED IN THE DESCRIPTION

This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 2 016 838 [0007]
• DE 10 2008 046 155 A1 [0008]
• US 4,818,508 [0009]
• DE 699 17 041 T2 [0010]
• EP 0 940 174 A2 [0010]
• DE 30 11 834 A1 [0011]
• US 3,516,786 [0012]
• US 2,882,244 [0013]
• US 3,078,639 [0013]
• US 3,865,924 [0013]
• US 4,433,981 [0013]
• US 4,493,715 [0013]

Claims (10)

A zeolitic molded body (10, 70, 80) comprising: a zeolite material (36) and a binder (38), wherein the molded body (10, 70, 80) has: i) macropores with a diameter of greater than 200 nm, preferably 1000 nm to 300 µm, measured by high-pressure mercury porosimetry, or ii) channels with a length of greater than 300 nm, preferably 1000 nm to 800 µm, measured by optical microscopy, or iii) a combination of i) and ii). Zeolitic shaped body (10, 70, 80) according to Claim 1 , wherein the zeolite material has a faujasite structure and a molar SiO ₂ /Al ₂ O ₃ ratio of 1.8 to 2.5. Zeolitic shaped body (10, 70, 80) according to Claim 1 or 2 , wherein the shaped body (10, 70, 80) further comprises: one or more inorganic additives or reinforcing materials (34, 87) selected from inorganic powders with a particle distribution of 1 to 1000 µm, inorganic fibers with a particle distribution of 1 to 5000 µm or metal splinters with a particle distribution of 10 to 2000 µm. Zeolitic shaped body (10, 70, 80) according to one of the Claims 1 until 3 , wherein the shaped body (10, 70, 80) is in the form of a plate (52), a tube (54), a square honeycomb (56), a hexagonal honeycomb or a triangular honeycomb (58). A method for producing a zeolitic molded body (10, 70, 80), comprising: - providing a zeolite material (36), a binder (38), and a pore-forming agent (39), wherein the pore-forming agent (39) is selected from the group consisting of: a) organic powders with a particle distribution of 5 to 2000 µm, b) organic fiber materials with a particle distribution of 5 to 2000 µm, c) solutions or gels of polymeric materials; - mixing the zeolite material (36) with the binder (38) and the pore-forming agent (39), optionally with the addition of water, to form a moldable mixture (73); - processing the moldable mixture (73) into a molded body; - drying and calcining the molded body. Procedure according to Claim 5 , wherein the moldable material mixture (73) further comprises one or more inorganic additives or reinforcing materials (34, 87) selected from the group consisting of d) inorganic powders with a particle distribution of 1 to 1000 µm, e) inorganic fibers with a particle distribution of 1 to 5000 µm f) metal chips with a particle distribution of 10 to 2000 µm or a combination. Procedure according to Claim 5 or 6 , wherein the processing comprises coating at least one surface side (72), preferably both surface sides (72), of a base molded body (71), which is preferably a plate-shaped molded body, with the moldable substance mixture (73). Method according to one of the Claims 5 or 6 , wherein the processing comprises the application of a film (81) to a surface side (82) of a base molded body (83), which is preferably a plate-shaped molded body, with the moldable substance mixture (73). Zeolitic shaped body (10, 70, 80) which is obtained by a process according to one of the Claims 5 until 8 are manufactured. Use of the zeolitic shaped body (10, 70, 80) according to Claim 1 or 9 as a sorption element (14, 15) in technical adsorption processes, preferably for the adsorption or desorption of CO ₂ or H ₂ O.