Device and method for extracting co 2 from air

Abstract

The invention relates to a device for extracting CO2 from air, comprising at least one extraction reactor (12) through which air can flow in an adsorption mode, wherein the at least one extraction reactor (12) comprises at least one CO2 extraction unit (18), through which air can flow in adsorption mode, for adsorbing CO2 present in the air (L, L') and at least one H2O extraction unit (16), through which air (L) can flow in adsorption mode, for adsorbing water present in the air (L), wherein the at least one H2O extraction unit (16), based on an air flow direction in adsorption mode, is upstream of the at least one CO2 extraction unit (18) and, based on an extraction gas flow direction in a desorption mode, downstream of the at least one CO2 extraction unit (18).

Description

[0001] 68677P WO Purem GmbH / 3308 WO

[0002] - 1 -

[0003] Device and method for extracting CO2 from air Description

[0004] The present invention relates to a device and a method for extracting CO2 from air.

[0005] To prevent an excessive increase in carbon dioxide (CC) levels in the Earth's atmosphere, which would exacerbate climate change, extensive measures are being taken to reduce CO2 emissions. However, these measures cannot reduce existing CC levels, i.e., they cannot remove CO2 already contained in the Earth's atmosphere. To achieve this, it is known, for example, to generate natural CO2 sinks through extensive reforestation or the restoration of peatlands.

[0006] German patent application DE 10 2024 120 259.9 discloses a device for extracting CO2 as an extraction gas from air as a gas mixture using a DAC (Direct Air Capture) process. In this device, an extraction reactor comprises a monolithic substrate with a plurality of channel-like cells through which the gas mixture flows. The substrate is coated with an adsorption material providing an adsorption surface. During the adsorption phase, as the gas mixture (i.e., air) flows through the cells, the extraction gas (CO2) contained within it is adsorbed onto the adsorption surface and thereby extracted from the gas mixture. In a subsequent desorption phase, the substrate, or rather its adsorption surface, is heated to a temperature above the desorption temperature of the extraction gas adsorbed onto the adsorption surface, and the released extraction gas is directed into an extraction gas storage tank.

[0007] The object of the present invention is to provide a device and a method for extracting CO2 from air with a simple structure and increased efficiency. 68677P WO Purem GmbH / 3308 WO

[0008] - 2 -

[0009] According to a first aspect of the present invention, this problem is solved by a device for extracting CO2 from air, comprising at least one extraction reactor through which air can flow in an adsorption operation, wherein the at least one extraction reactor comprises at least one CO2 extraction unit through which air can flow in an adsorption operation for adsorbing CO2 contained in the air and at least one H2O extraction unit through which air can flow in an adsorption operation for adsorbing water contained in the air, wherein the at least one H2O extraction unit is arranged upstream of the at least one CO2 extraction unit with respect to an air flow direction in adsorption operation and downstream of the at least one CO2 extraction unit with respect to an extraction gas flow direction in desorption operation.

[0010] The device constructed according to the invention is structured such that, during adsorption operation, the air providing a gas mixture from which an extraction gas, i.e., CO2, is to be extracted, first flows through the at least one FW extraction unit and subsequently through the at least one CO2 extraction unit. Since water contained in the air can be essentially completely adsorbed in the at least one FW extraction unit, water-depleted or essentially anhydrous air leaves the at least one FW extraction unit and enters the at least one CO2 extraction unit during adsorption operation.Since this essentially prevents water contained in the air from being adsorbed in at least one CO2 extraction unit, thus impairing the ability to adsorb CO2, the efficiency with which CO2 can be adsorbed and thus extracted from the air in adsorption operation is significantly increased.

[0011] In the device constructed according to the invention, during the transition from an adsorption operation, in which air is successively passed through the at least one FW extraction unit and the at least one CO2 extraction unit to adsorb water on the one hand and CO2 on the other, to a desorption operation, in which desorbed CO2 and desorbed water are discharged from the at least one extraction reactor, the flow direction 68677P WO Purem GmbH / 3308 WO

[0012] - 3 - conversely. This results in a common gas stream or a gaseous mixture of desorbed CO2 and desorbed water being discharged from the at least one extraction reactor during desorption operation. This simplifies the design of the device for extracting CO2 from air. At the same time, this reversal of the flow direction ensures that no water or water vapor enters the area of ​​the at least one CO2 extraction unit and is adsorbed there, either during desorption operation or during the transition from desorption to adsorption operation.

[0013] It should be noted that the present invention can be used particularly advantageously in the extraction of CO2 (carbon dioxide) from the Earth's atmosphere, i.e., from air. However, the present invention can also be used in conjunction with other CO2-containing gas mixtures. In this respect, air is merely to be considered as an example or placeholder for such CO2-containing gas mixtures. All aspects of the invention described below can be applied equally to devices or processes with which CO2 is extracted as an extraction gas from other CO2-containing gas mixtures besides air.

[0014] Similarly, CO2 as an extraction gas is only to be considered as an example or placeholder for any other gases contained in a gas mixture and to be extracted from it, which can be extracted from the gas mixture by adsorption and subsequently released again by desorption and directed into a suitable storage medium. All aspects of the invention described below can be applied equally to devices or processes with which extraction gases other than CO2 are extracted from air or other gas mixtures containing them.

[0015] In order to convey the air, which is to be freed from an extraction gas, in particular CO2, as a gas mixture, through the at least one reaction reactor during adsorption operation, it is proposed that an air conveying device, preferably a blower or compressor, be associated with the at least one extraction reactor for conveying air through the at least one H2O- 68677P WO Purem GmbH / 3308 WO

[0016] - 4 -

[0017] Extraction unit and at least one CO2 extraction unit following the at least one H2O extraction unit in the direction of airflow.

[0018] Since, in principle, no separate streams of desorbed water and desorbed CO2 need to be conveyed from the at least one extraction reactor in the device constructed according to the invention, an extraction gas conveying device, preferably an extraction gas discharge pump, can be provided to support a simple structure in association with the at least one CO2 extraction unit and the at least one FW extraction unit, for conveying CO2 in desorption mode from the at least one CC extraction unit towards a CO2 storage unit and for conveying water in desorption mode from the at least one FW extraction unit towards an FW storage unit.

[0019] In order to generate the combined flow of desorbed water and desorbed CO2, the extraction gas conveying device can be designed to convey CO2 through the FW extraction unit during desorption operation.

[0020] In order to store or temporarily store the two desorbed media CO2 and water separately in storage tanks provided for this purpose, a water separation unit can be provided in association with the extraction gas conveying device, preferably downstream of the extraction gas conveying device, for separating water from the gaseous mixture of water and CO2 leaving the at least one extraction reactor during desorption operation and for supplying liquid water to the water storage tank.

[0021] In order to ensure a defined flow of CO2 into the CO2 storage even downstream of the FW separation unit, it is proposed that a 002 conveying device, preferably a CO2 pump, be provided downstream of the FW separation unit to convey CO2 to the CO2 storage.

[0022] For efficient desorption, a CC extraction unit heating arrangement can be assigned to the at least one CO2 extraction unit to heat the at least one CC extraction unit for desorbing the adsorbate contained therein. 68677P WO Purem GmbH / 3308 WO

[0023] - 5 - onsbetrieb adsorbed CO2 be provided, and in association with the at least one FW extraction unit an FW extraction unit heating arrangement for heating the at least one FW extraction unit for desorbing water adsorbed therein in adsorption operation may be provided.

[0024] In order to achieve an intensive thermal interaction with the water or CO2 adsorbing material, it is proposed that the at least one CC extraction unit comprises at least one CO2 extraction chamber containing CO2 adsorption granules with an adsorption surface for adsorbing CO2-providing CO2 adsorption bodies, or / and that the at least one FW extraction unit comprises at least one FW extraction chamber containing FW adsorption granules with an adsorption surface for adsorbing water-providing FW adsorption bodies.

[0025] For particularly efficient CO2 or water adsorption, the CO2 adsorbents can be constructed with zeolite material or a metal-organic material such as MOF CALF-20, and / or the water adsorbents can be constructed with silica gel (silica, silicon dioxide). Using such a material for the water adsorbents is particularly advantageous because this material has a comparatively low adsorption capacity for CO2. As an alternative material for such water adsorbents, alumina (aluminum oxide) can be used.

[0026] The CO2 extraction unit heating arrangement can comprise at least one electrically excitable heating element arranged in the CO2 extraction chamber and surrounded by the CC adsorption granules. Furthermore, the H2O extraction unit heating arrangement can comprise at least one electrically excitable heating element arranged in the H2O extraction chamber and surrounded by the H2O adsorption granules.

[0027] To enhance thermal interaction and thereby improve heating efficiency during desorption operation, it is proposed that the CO2- 68677P WO Purem GmbH / 3308 WO

[0028] - 6 -

[0029] Extraction unit heating arrangement or / and in the case of the H2O extraction unit heating arrangement, the at least one electrically excitable heating element comprises at least one heating conductor constructed with flat ribbon material and extending in a winding manner.

[0030] To prevent water contained in the air during adsorption operation from entering the area of ​​the at least one CO2 extraction unit, a sensor arrangement may be provided to supply information representing the water content in the air supplied to the at least one H2O extraction unit during adsorption operation, or / and a sensor arrangement may be provided to supply information representing the water content in the air leaving the at least one H2O extraction unit during adsorption operation.

[0031] The extraction reactor can be designed in such a way that the at least one H2O extraction unit and the at least one CC extraction unit are essentially identical in construction to each other as separate assemblies, or that the at least one H2O extraction unit and the at least one CO2 extraction unit are combined in one assembly.

[0032] According to a further aspect, the problem mentioned at the outset is solved by a method for extracting CO2 from air by means of a device according to the invention for extracting CO2 from air, comprising the following measures: a) in an adsorption operation, passing air through the at least one H2O extraction unit of the at least one extraction reactor and subsequently through the at least one CO2 extraction unit of the at least one extraction reactor, b) in a desorption operation, desorbing CO2 adsorbed in the at least one CO2 extraction unit and desorbing water adsorbed in the at least one H2O extraction unit and removing a mixture of desorbed CO2 and desorbed water from the at least one extraction reactor. 68677P WO Purem GmbH / 3308 WO

[0033] - 7 -

[0034] To produce the mixture of desorbed CO2 and desorbed water, in measure b) desorbed CO2 in the at least one CC extraction unit can be passed through the at least one FW extraction unit.

[0035] For efficient operation, measures a) and b) can be carried out alternately.

[0036] To ensure that, during desorption operation, only the materials to be desorbed are directed, for example, towards designated storage facilities, it is proposed that, after carrying out measure a) and before the next carrying out measure b), or / and after carrying out measure b) and before the next carrying out measure a), measure c) be carried out to discharge residual gas contained in the at least one FW extraction unit and to discharge residual gas contained in the at least one CC extraction unit. With repeated alternating execution of measures a) and b), such measure c) can be carried out at each transition from adsorption operation to desorption operation, or / and at each transition from desorption operation to adsorption operation.

[0037] In order to utilize the available adsorption potential as much as possible on the one hand, but to avoid introducing air containing non-adsorbed water into the at least one CC extraction unit on the other, it is proposed that a duration for adsorption operation be determined as a function of the relative humidity of the air introduced into the at least one FW extraction unit during adsorption operation.

[0038] Since the material intended for water adsorption becomes saturated more quickly or earlier with increasing relative humidity, i.e., increasing water content in the air, it is proposed that the duration of adsorption operation decrease with increasing relative humidity. 68677P WO Purem GmbH / 3308 WO

[0039] - 8 -

[0040] Regardless of whether it is already possible to ensure that air with a water content that impairs the adsorption potential for CO2 is not introduced into the at least one CO2 extraction chamber by taking the relative humidity into account, it may be provided that the adsorption operation is terminated if a water content in the air leaving the at least one FW extraction unit in the direction of the at least one CO2 extraction unit during adsorption operation exceeds an assigned threshold value.

[0041] The present invention is described in detail below with reference to the accompanying figures. These show:

[0042] Fig. 1 shows a device for extracting CO2 from air in principle;

[0043] Fig. 2 shows a longitudinal section view through an extraction reactor with an FW extraction unit and a CO2 extraction unit;

[0044] Fig. 3 shows a longitudinal sectional view of an alternatively designed extraction reactor, corresponding to Fig. 2;

[0045] Fig. 4 is a diagram illustrating the relationship between relative humidity and the time available for adsorption operation;

[0046] Fig. 5 shows a time diagram illustrating a work cycle of adsorption and desorption operation.

[0047] In Fig. 1, a device for extracting CO2 from air is generally designated by 10. The device 10 comprises as its central component an extraction reactor 12, to which air L is supplied as a gas mixture by means of an air conveying device 14, for example designed as a blower or compressor, from which CO2 is to be extracted as the extraction gas. 68677P WO Purem GmbH / 3308 WO

[0048] - 9 -

[0049] The extraction reactor 12 comprises – with respect to an airflow direction in adsorption operation – an FW extraction unit 16 and a CC extraction unit 18 arranged successively in the direction of flow. A first shut-off valve 20 is arranged upstream of the extraction reactor 12 or upstream of the FW extraction unit 16, and a second shut-off valve 22 is arranged downstream of the extraction reactor 12 or downstream of the CO2 extraction unit 18.

[0050] A third shut-off valve 24 is provided in a flow path from the extraction reactor 12 to a fresh water storage tank 26 and a CO2 storage tank 28. Downstream of the third shut-off valve 24, an extraction gas conveying device 30, for example an extraction gas discharge pump, is provided, through which gaseous medium contained in the fresh water extraction unit 16 and the carbon dioxide extraction unit 18 can be pumped out and conveyed via a directional control valve 32 either to the fresh water storage tank 26 or the CO2 storage tank 28 or to the environment.

[0051] A water vapor separation unit 34 is arranged downstream of the extraction gas conveying device 30. In the water vapor separation unit 34, water or water vapor contained in the extraction gas conveyed by the extraction gas conveying device 30 can be condensed and released in liquid form to the water vapor storage tank 36.

[0052] Downstream of the water separation unit 34, a CC conveying device 36, for example a CO2 pump, is provided. The CO2 conveying device 36 conveys CO2, essentially completely free of water, downstream of the water separation unit 34 to the CO2 storage tank 28.

[0053] All shut-off valves 20, 22, 24, as well as the air conveying device 14, the extraction gas conveying device 30, the CO2 conveying device 36, and the directional control valve 32 are controlled by a control unit 42. Depending on the operating state, this unit activates or deactivates the various conveying devices and adjusts the various shut-off valves and directional control valves to ensure the necessary flow connections. 68677P WO Purem GmbH / 3308 WO

[0054] - 10 -

[0055] Figure 2 shows a more detailed example of the construction of the extraction reactor 12. It should be emphasized that in the embodiment shown in Figure 2, the FW extraction unit 16 and the CC extraction unit are essentially identical in construction, so that the following description is generally applicable to these two extraction units 16, 18.

[0056] Each of the two extraction units 16, 18 comprises an extraction chamber 44 or 44', which is bounded between two end walls 46, 48 and a circumferential wall, generally designated 50 or 50', of a respective extraction unit housing 52 or 52'. The two end walls 46, 48 are permeable to gaseous media.

[0057] In the extraction chamber 44, a heating element 56 is arranged, which can be excited and thereby heated by applying an electrical voltage to one or more connection elements 54 and essentially provides a heating arrangement for an FW extraction unit. In the illustrated embodiment, the heating element 56 comprises a heating conductor 58 made of metallic flat ribbon material, which is arranged in the extraction chamber 44 such that its narrow sides are oriented towards the two end walls 46, 48, and which is preferably received in the extraction chamber 44 with a winding course, for example a meandering or spiral course.

[0058] Extraction chamber 44 of the H2O extraction arrangement 18 contains an H2O adsorption granulate, generally designated 60. This granulate comprises a multitude of, for example, spherical H2O adsorption bodies 62, which essentially completely fill the volume of the extraction chamber 44 and essentially completely embed the heating element 56 or heating conductor 58 that provides the heating arrangement for the H2O extraction unit. Silica gel can be used as the material for the H2O adsorption bodies 62, as it exhibits high selectivity for the adsorption of water or water vapor and only comparatively low selectivity for CO2. Aluminum oxide (aluminum oxide) can be used as an alternative material for such H2O adsorption bodies. 68677P WO Purem GmbH / 3308 WO

[0059] - 11 -

[0060] Similarly, the extraction chamber 44' of the CO2 extraction unit 18 is filled with CO2 adsorption granules 64. The CO2 adsorption granules 64 comprise a plurality of CO2 adsorption bodies 66, for example, with a spherical shape, which essentially completely embed the heating element 56' or heating conductor 58' provided in the extraction chamber 44' of the CO2 extraction unit 18 and which essentially constitutes a CO2 extraction unit heating arrangement. Zeolite material or a metal-organic material, such as MOF CALF-20, which exhibits high selectivity for the adsorption of CO2, can be used as the material for the CO2 adsorption bodies 66.

[0061] The two extraction units 16, 18, which are essentially identical in construction and differ only in the type of granules used, are assembled sequentially in the direction of flow, such that a downstream connecting flange 69' provided on the extraction unit housing 52 of the H2O extraction unit 16 is connected to an upstream connecting flange 68' provided on the extraction unit housing 52' of the CO2 extraction unit 18, for example, by means of a pipe clamp or the like. An upstream connecting flange 68 of the extraction unit housing 52 of the H2O extraction unit 16 can be connected to upstream system sections, for example, the first shut-off valve 20 or the CO2 extraction unit 18.the air conveying device 14, can be connected, and a downstream connecting flange 69' of the extraction unit housing 52' of the CO2 extraction unit 18 can be connected to downstream system areas, for example the second shut-off valve 22.

[0062] An alternative embodiment of an extraction reactor 12 comprising an H2O extraction unit 16 and a CO2 extraction unit 18 is shown in Fig. 3. In this embodiment, the extraction units 16 and 18 are combined into a single assembly and provided in a common extraction unit housing 52, which has a circumferential wall 50". This extraction unit housing 52 has a connecting flange 68 at its upstream end region (relative to the airflow direction L during adsorption operation) and a connecting flange 69' at its downstream end region. As in the above- 68677P WO Purem GmbH / 3308 WO

[0063] - 12 - In the embodiment shown below, each extraction unit 16, 18 has an extraction chamber 44, 44' filled with the F-adsorption granules 60 or the CO2-adsorption granules 40 and bounded between two end walls and the circumferential wall, with the heating element 56, 56' arranged therein.

[0064] Combining the two extraction units 16, 18 into one assembly further simplifies the construction of the extraction reactor 12 and supports a compact design of the same.

[0065] In an adsorption operation, the two shut-off valves 20, 22 are set to their open position by means of the control unit 42, so that air L conveyed by the air conveying arrangement 14 can flow through the extraction reactor 12. The air L, containing both water (i.e., gaseous water or water vapor) and CO2, enters the H2O extraction unit 16, so that the water contained in the air L is adsorbed onto the surfaces of the H2O adsorption bodies 62. Since the third shut-off valve 24 is in its closed position during adsorption operation, water-depleted air L', or air containing essentially no water or water vapor, leaves the water extraction unit 16 in the direction of the CO2 extraction unit 18. Because water-depleted air L' is conveyed to the CO2 extraction unit 18, there is no risk of water being adsorbed on the surfaces of the CO2 adsorption bodies 66.The entire surface area provided by the CO2 adsorption bodies 66 can thus be used for the adsorption of CO2. The water- and CO2-depleted air L” leaves the extraction reactor 12 via the second shut-off valve 22 and is, for example, expelled to the environment.

[0066] During the transition from adsorption to desorption operation, shut-off valves 20 and 22 are first closed, the third shut-off valve 24 is opened, and the directional control valve 32 is set so that, in a draining operation, the residual air still contained in extraction units 16 and 18 is essentially completely extracted and released to the environment. The residual air contained in the CO2 extraction unit 16 flows through the H2O extraction unit 16 via the third shut-off valve 24. (68677P WO Purem GmbH / 3308 WO)

[0067] - 13 - the directional control valve 32 to the environment. This prevents residual air R and any water contained in the FW extraction unit 16 from entering the area of ​​the CO2 extraction unit 18 at this time. This process for pumping out residual air or residual gas R or R' from the extraction units 16, 18 can, for example, be carried out over a predetermined period of time.

[0068] Subsequently, a desorption process is initiated in which an electrical voltage is applied to the heating elements 56 and 56' of the two extraction reactors 16 and 18, respectively. This heating of the H₂O adsorption granules 60 and the CO₂ adsorption granules 64, respectively, raises the temperature above the desorption temperature of water and CO₂. As a result, adsorbed water is released, i.e., desorbed, in the H₂O extraction unit 16. Similarly, adsorbed CO₂ is desorbed in the CO₂ extraction unit 18.

[0069] For example, at the start of desorption operation, the directional control valve 32 is positioned to establish a flow connection between the extraction gas conveying device 30 and the H2O separation unit 34. Subsequently, the two conveying devices 30 and 36 are put into operation. In the CO2 extraction unit 18, CO2 desorbed is conveyed, in particular by the conveying action of the extraction gas conveying device 30, from the CO2 extraction unit 18 through the H2O extraction unit 16, so that a mixture of desorbed CO2 and desorbed H2O is formed in the H2O extraction unit. Due to the resulting flow of desorbed CO2 from the CO2 extraction unit 18 into the H2O extraction unit 16, the entry of desorbed water into the CO2 extraction unit 18 is prevented.This prevents water from being adsorbed onto the CO2 adsorption bodies 66 of the CO2 adsorption granules 64 and reducing the storage capacity for CO2 in a subsequent adsorption operation.

[0070] The flow direction of the gases conveyed out of extraction reactor 12 during desorption operation, or of the mixture of desorbed CO2 and desorbed water, as well as the flow direction during emptying operation in the transition between adsorption and desorption operation from extraction reactor 12 - 68677P WO Purem GmbH / 3308 WO

[0071] - 14 - The direction of flow of the residual gases R, R' drawn in is thus opposite to the flow direction of the air L, L', L" conveyed through the extraction reactor 12 during adsorption operation. While in adsorption operation the FW extraction unit 16 is located upstream of the CO2 extraction unit 18, in desorption operation the FW extraction unit 16 is located downstream of the CO2 extraction unit 18.

[0072] The mixture of water desorbed in the FW extraction unit 16 and CO2 desorbed in the CO2 extraction unit is conveyed by the extraction gas conveying device 30 to the FW separation unit 34, where water contained in this mixture in gaseous form, i.e., as water vapor, can condense upon cooling and is directed as liquid water into the FW storage tank 26. This water can be used in further processes, for example, for the production of hydrogen.

[0073] The gas leaving the FW separation unit 34 under the conveying action of the 002 conveying device 36 is essentially formed by the CO2 desorbed in the CO2 extraction unit 18 and flowing through the FW extraction unit 16 and the FW separation unit 34. This CO2 flows into the CO2 storage unit 34, where it can be temporarily stored under pressure, for example, to be used subsequently in further processes, such as for the production of synthetic fuels or as a feedstock in the chemical industry, or to be permanently stored, for example, in underground storage facilities.

[0074] The previously described process of adsorbing and desorbing water on the one hand and CO2 on the other can be carried out repeatedly in successive work cycles. For example, during each transition from adsorption to desorption operation, or from desorption to subsequent adsorption operation, a process can be performed to empty or pump out the gaseous media still contained in the respective extraction reactors, particularly to ensure that essentially no water or water vapor enters the area of ​​the CO2 extraction unit 18. (See 68677P WO Purem GmbH / 3308 WO)

[0075] - 15 -

[0076] This method reliably prevents the subsequent adsorption of CO2-impairing water on the CO2 adsorption bodies 66.

[0077] Figure 4 illustrates, using curve K1, that the F storage capacity of the FW adsorption granules 60 generally increases with increasing relative humidity of the air L introduced into the FW extraction unit 16. Despite this increasing storage capacity for water contained in the air L with increasing relative humidity, the time available during adsorption operation to adsorb essentially all water contained in the air as water vapor onto the FW adsorption granules 60, as illustrated by curve K2, decreases with increasing relative humidity. This means that, during adsorption operation, less time is available with increasing relative humidity to ensure that essentially no water flows with the air L' leaving the FW extraction unit 16 towards the CC extraction unit 18 and can be adsorbed onto the surface of the CO2 adsorption granules 64.

[0078] To take this into account during the repeated alternating execution of adsorption and desorption operations, a sensor arrangement, generally designated 72, is provided in the device 10, for example, upstream of the FW extraction unit of the extraction reactor 12, in particular upstream of the FW adsorption granules 60. The sensor arrangement 72 comprises a sensor whose output signal represents the water content in the air L conveyed to the extraction reactor 10 by the air conveying device 14 and inputs this information or a corresponding sensor signal into the control unit 42.

[0079] Based on this information, the duration for each adsorption operation within a work cycle comprising one adsorption and one desorption operation can be determined during a DAC process. Since the time until water breakthrough through the FW extraction unit 16 decreases with increasing relative humidity, the control unit 42 sets the duration specified for each adsorption operation. 68677P WO Purem GmbH / 3308 WO

[0080] - 16 -

[0081] The time duration is set such that it decreases with increasing relative humidity, i.e., increasing water content in the air, thus ensuring that adsorption operation is terminated and transitioned to desorption operation before water breaks through the hhO extraction unit 16. For this purpose, the control unit 42 compares the information generated by the sensor arrangement 72, representing the water content in the air L, with an associated, very low threshold value. If this threshold value is exceeded, the various conveying devices and valves are controlled accordingly to switch from adsorption operation to desorption operation.

[0082] Since the desorption rate of water or CO2 in the respective extraction units 16, 18 is generally known from their structural specifications, a defined time interval can be specified for carrying out a desorption operation, or it can be detected, using respective sensor arrangements not shown in the figures, when essentially no more water or CO2 is released from the extraction units 16, 18, in order to end a desorption operation based on this information and to switch to the next adsorption operation.

[0083] Alternatively or additionally to measuring the relative humidity of the air L introduced into the extraction reactor 12, the water content of the air L' leaving the H2O extraction unit 16 towards the CO2 extraction unit 18 can also be measured by means of a sensor arrangement 74. The sensor arrangement 74 can, for example, be located downstream of the H2O extraction chamber 44 in the area of ​​the H2O extraction unit 16 and upstream of the fifth shut-off valve 40. If the output signal of the sensor arrangement 74 measuring the water content in the air L' indicates that the air L directed towards the CO2 extraction unit 18 has a water content exceeding an assigned threshold value, this can also be used to terminate adsorption operation and switch to desorption operation by means of the control unit 42. 68677P WO Purem GmbH / 3308 WO

[0084] - 17 -

[0085] Figure 5 shows the development of the CC concentration and the FW concentration for a working cycle comprising adsorption and desorption operation. At time Ts, the adsorption operation is terminated and transitioned to desorption operation, for example, via an intermediate emptying operation. The CO2 and FW concentrations in the air L" leaving the extraction reactor 12 during adsorption operation are measured downstream of the CO2 extraction unit 18, for example, in the area of ​​the second shut-off valve 22. It can be seen that during the entire adsorption operation, essentially no water or CO2 is contained in the air L" leaving the extraction reactor 12.

[0086] During desorption operation, the depicted CO2 concentration and FW concentration correspond to the respective concentrations of CO2 and FW contained in the mixture of desorbed CO2 and desorbed water that leaves the extraction reactor 12 via the third shut-off valve 24. It is clearly evident that an increase in the concentrations of CO2 and H2O contained in the mixture occurs when the heating elements 56, 56' are excited.

[0087] As previously explained, the time Ts at which the adsorption operation is terminated can be determined based on the relative humidity L of the air introduced into the H2O extraction unit 16. This ensures that, while preventing water breakthrough towards the CO2 extraction unit 16, the H2O storage capacity of the H2O adsorption granules 60 is essentially fully utilized, and consequently, a maximum storage quantity of CO2 is achieved in the CO2 extraction unit 18. It is therefore clear that the amount of CO2 adsorbed and thus stored in the CO2 adsorption unit 18 depends on the duration specified for each adsorption operation. The CO2 storage capacity of the CO2 extraction unit 18 should therefore be dimensioned such that, even with the maximum possible duration of the adsorption operation, the maximum CO2 storage capacity of the CO2 adsorption granules 64 is not exceeded.68677P WO Purem GmbH / 3308 WO.

[0088] - 18 -

[0089] Finally, it should be noted that the extraction reactor 12 can be structurally varied in a wide variety of ways. For example, a plurality of FW extraction units 16 can each be provided with an F extraction chamber 44 and H2O adsorption granules 60 arranged therein surrounding a heating conductor 58. These H2O extraction units 16 can be connected to each other in parallel or in series with air L flowing through them. Similarly, several CO2 extraction units 18 can be connected to each other in parallel or in series to increase the CO2 storage capacity accordingly.In principle, the device 10 can also provide several extraction reactors 12 and, for example, operate in phase-shifted mode relative to each other, so that at least one of the extraction reactors 12 is always operating in adsorption mode and at least one of the extraction reactors 12 is operating in desorption mode, thus enabling quasi-continuous operation for extracting CO2 from air.

Claims

68677P WO Purem GmbH / 3308 WO - 19 - Claims 1. Device for extracting CO2 from air, comprising at least one extraction reactor (12) through which air flows in an adsorption operation, wherein the at least one extraction reactor (12) comprises at least one CO2 extraction unit (18) through which air flows in an adsorption operation for adsorbing CO2 contained in the air (L, L') and at least one FW extraction unit (16) through which air (L) flows in an adsorption operation for adsorbing water contained in the air (L), wherein the at least one FW extraction unit (16) is arranged upstream of the at least one CO2 extraction unit (18) with respect to an air flow direction in adsorption operation and downstream of the at least one CO2 extraction unit (18) with respect to an extraction gas flow direction in desorption operation.

2. Device according to claim 1, characterized in that an air conveying device (14), preferably a blower or compressor, is provided in association with the at least one extraction reactor (12) for conveying air (L, L', L“) in adsorption operation through the at least one FW extraction unit (16) and the at least one CC extraction unit (18) following the at least one FW extraction unit (16) in the direction of airflow.

3. Device according to claim 1 or 2, characterized in that an extraction gas conveying device (30), preferably an extraction gas discharge pump, is provided in association with the at least one CO2 extraction unit (18) and the at least one FW extraction unit (16) for conveying CO2 in desorption mode from the at least one CC extraction unit (16) towards a CO2 storage (28) and for conveying water in desorption mode from the at least one FW extraction unit towards an FW storage (26). 68677P WO Purem GmbH / 3308 WO - 20 - 4. Device according to claim 3, characterized in that the extraction gas conveying device (30) is designed to convey CO2 through the FW extraction unit (16) during desorption operation.

5. Device according to claim 3 or 4, characterized in that, in association with the extraction gas conveying device (30), preferably downstream of the extraction gas conveying device (30), a water separation unit (34) is provided for separating water from a mixture of water and CO2 leaving the at least one extraction reactor (12) in desorption operation and for supplying liquid water to the water storage tank (26).

6. Device according to claim 5, characterized in that a CO2 conveying device (36), preferably a CO2 pump, is provided downstream of the FW separation unit (34) for conveying CO2 to the CO2 storage (28).

7. Device according to one of claims 1-6, characterized in that a CC extraction unit heating arrangement is provided in association with the at least one CO2 extraction unit (18) for heating the at least one CC extraction unit (18) for desorbing CO2 adsorbed therein in adsorption operation, and that an FW extraction unit heating arrangement is provided in association with the at least one FW extraction unit (16) for heating the at least one FW extraction unit (16) for desorbing water adsorbed therein in adsorption operation.

8. Device according to one of claims 1-7, characterized in that the at least one CC extraction unit (18) comprises at least one CC extraction chamber (44') containing a CC adsorption granulate (64) with an adsorption surface for adsorbing CO2-providing CO2 adsorption bodies (66), 68677P WO Purem GmbH / 3308 WO - 21 - or / and that the at least one FW extraction unit (16) has at least one FW extraction chamber (44) containing an FW adsorption granulate (60) with an adsorption surface for adsorbing water-providing FW adsorption bodies (62).

9. Device according to claim 8, characterized in that the CC adsorption bodies (66) are constructed with zeolite material or organometallic material, and / or that the FW adsorption bodies (62) are constructed with silica gel or alumina.

10. Device according to claim 7 and claim 8 or 9, characterized in that the CC extraction unit heating arrangement comprises at least one electrically excitable heating element (56') arranged in the CO2 extraction chamber (44') and surrounded by the CO2 adsorption granules (64), and / or that the H2O extraction unit heating arrangement comprises at least one electrically excitable heating element (56) arranged in the H2O extraction chamber (44) and surrounded by the H2O adsorption granules (60).

11. Device according to claim 10, characterized in that in the CC extraction unit heating arrangement and / or in the H2O extraction unit heating arrangement, the at least one electrically excitable heating element (56, 56') comprises at least one heating conductor (58, 58') constructed with flat ribbon material and extending in a winding manner.

12. Device according to one of claims 1-11, characterized by a sensor arrangement (72) for providing information representing the water content in the air (L) supplied to the at least one H2O extraction unit (16) during adsorption operation or / and a sensor arrangement (74) for providing information representing the water content in the air (L') leaving the at least one H2O extraction unit (16) during adsorption operation. 68677P WO Purem GmbH / 3308 WO - 22 - 13. Device according to one of claims 1-12, characterized in that the at least one FW extraction unit (16) and the at least one CO2 extraction unit (18) are designed as separate assemblies that are essentially identical in construction to each other, or that the at least one FW extraction unit (16) and the at least one CO2 extraction unit (18) are combined in one assembly.

14. Method for extracting CO2 from air by means of a device for extracting CO2 from air according to any one of claims 1-13, comprising the measures: a) in an adsorption operation, passing air through the at least one FW extraction unit (16) of the at least one extraction reactor (12) and subsequently through the at least one CO2 extraction unit (18) of the at least one extraction reactor (12), b) in a desorption operation, desorbing CO2 adsorbed in the at least one CO2 extraction unit (18) and desorbing water adsorbed in the at least one FW extraction unit (16) and discharging a mixture of desorbed CO2 and desorbed water from the at least one extraction reactor (12).

15. Method according to claim 14, characterized in that in measure b) for generating the mixture of desorbed CO2 and desorbed water in the at least one CO2 extraction unit (18) desorbed CO2 is passed through the at least one FW extraction unit (16).

16. Method according to claim 14 or 15, characterized in that measures a) and b) are carried out alternately.

17. Method according to one of claims 14-16, 68677P WO Purem GmbH / 3308 WO - 23 - characterized in that, after carrying out measure a) and before the next carrying out measure b) or / and after carrying out measure b) and before the next carrying out measure a), a measure c) is carried out to remove residual gas (R) contained in the at least one H2O extraction unit (16) and residual gas (R') contained in the at least one CC extraction unit (18).

18. Method according to one of claims 14-17, characterized in that a time period for the adsorption operation is determined as a function of the relative humidity of the air (L) introduced into the at least one FW extraction unit (16) during the adsorption operation.

19. Device according to claim 18, characterized in that the duration of the adsorption operation decreases with increasing relative humidity.

20. Method according to one of claims 14-19, characterized in that the adsorption operation is terminated when the water content in the air (L') leaving the at least one FW extraction unit (16) in the direction of the at least one CO2 extraction unit (18) during adsorption operation exceeds an associated threshold value.

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