System for reducing carbon dioxide from the ambient air and method for operating the system

Abstract

The invention relates to a system (100) for reducing carbon dioxide from the ambient air, comprising a first device (10) for adsorbing the carbon dioxide from the ambient air using a pourable or flowable adsorption material (1) and comprising a second device (20) for desorbing the adsorption material (1) enriched with carbon dioxide, wherein the second device (20) is designed as a device (20) separate from the first device (10), wherein the first device (10) has a supply region (12) for supplying the adsorption material (1) and a discharge region (14) for discharging the adsorption material (1) enriched with carbon dioxide from the first device (10).

Description

[0001] Description

[0002] Plant for reducing carbon dioxide from ambient air and method for operating the plant

[0003] Technical area

[0004] The invention relates to a system for reducing carbon dioxide from ambient air, which is characterized by a particularly advantageous design of a device for adsorbing carbon dioxide from the ambient air using a pourable or free-flowing adsorption material. Furthermore, the invention relates to a method for operating a system designed according to the invention.

[0005] State of the art

[0006] In order to limit the warming of the Earth's atmosphere, it is already known that the CO2 content, which has increased due to industrialization, can be actively reduced. So-called "direct air capture" systems (DAC) can be used for this purpose (source: https: / / de.wikipedia.org / wiki / Direct_Air_Capture). Such a system is characterized in principle by the fact that, in a first facility, the carbon dioxide is absorbed from the ambient air by an adsorption material. In a second facility, the carbon dioxide is extracted again from the carbon dioxide-enriched adsorption material in a desorption process, so that the carbon dioxide can then be permanently bound, e.g., by injecting it into geological cavities.

[0007] Furthermore, DE 202012 008401 U1 discloses the use of a shaft dryer for drying loose products, such as grain. The product to be dried is fed into an upper area of ​​the silo-like shaft dryer and can be discharged by gravity to a discharge area located on the underside of the shaft dryer, for example, to a truck. To dry the product (food or grain), the housing of the shaft dryer is interspersed with a plurality of tubular feed and discharge elements for air. The air is heated before flowing through the product and cooled again after flowing through the food, for example, using a heat exchanger, in order to utilize the energy present in the heated air.What is important here is that the product to be treated (grain), the moisture of which is to be reduced by the heated air, is moved vertically from top to bottom in the shaft dryer, while the air used to dry the grain flows through the shaft dryer in a transverse direction.

[0008] Disclosure of the invention

[0009] The system according to the invention for reducing carbon dioxide from the ambient air or the atmosphere with the features of claim 1 has the advantage that it enables a particularly effective flow of the ambient air through the adsorption material and at the same time has a particularly compact design.

[0010] The invention is based on the idea of ​​using the system known per se from the prior art for drying products such as grain to load the adsorption material with carbon dioxide from the air, so that the shaft dryer thus solves a different or inverse task compared to the prior art: the free-flowing material is loaded with components from the air such as carbon dioxide and / or humidity, i.e. water, whereas a grain dryer serves to remove the moisture from the grain and thus to enrich the air with water. Furthermore, the ambient air to be cleaned flows through the housing of the first device of the system according to the invention essentially in a transverse direction with respect to a (vertically oriented) longitudinal direction of the housing, while the adsorption material used to treat the ambient air flows through the housing in its longitudinal direction.In contrast, in the known shaft dryer, the product to be treated flows through the housing in its longitudinal direction, while the ambient air used for drying (whose effect corresponds to that of an auxiliary treatment agent corresponding to the adsorption material) flows through the housing in the transverse direction.

[0011] Against the background of the above explanations, a system for reducing carbon dioxide from the ambient air with the features of claim 1 therefore comprises a first device for adsorbing the carbon dioxide from the ambient air using a pourable or free-flowing adsorption material and a second device for desorbing the carbon dioxide-enriched adsorption material. The second device is designed as a separate device from the first device, wherein the first device has a feed area for feeding the adsorption material and a discharge area for discharging the carbon dioxide-enriched adsorption material from the first device.The first device has a shaft-shaped housing with an at least substantially vertically oriented longitudinal axis, which is designed so that the adsorption material passes from the feed area into the discharge area under the effect of gravity, wherein preferably at least substantially horizontally arranged, tubular feed elements for the air and at least substantially horizontally arranged, tubular discharge elements for the air are arranged in the housing, wherein the air can be supplied or discharged on opposite sides of the housing, and wherein the supply and discharge elements each end at a distance from the side of the housing facing away from them.

[0012] Advantageous further developments of the system according to the invention for reducing carbon dioxide from the ambient air are listed in the subclaims.

[0013] In order to use the adsorption material as effectively as possible to store carbon dioxide and to provide a large surface area for the air to act on the adsorption material, a preferred development of the system has the feature that the feed elements and the discharge elements are each arranged one above the other in several planes running perpendicular to the longitudinal axis of the housing, with planes with feed elements and planes with discharge elements alternating. When the system is used or operated as intended, the longitudinal axis of the housing is essentially vertical.

[0014] In a preferred development of the latter proposal, the supply elements and the discharge elements of two superimposed levels are arranged offset from one another in a direction perpendicular to the longitudinal axis. Such a configuration makes it possible, on the one hand, to maximize the number of supply elements and discharge elements in the individual levels, and, on the other hand, to maximize the air flow path between a supply element and a discharge element on another level, thus enabling the adsorption material to act on the air for the longest possible time.

[0015] It is further preferred that the feed elements and the discharge elements are each identically designed, at least in themselves, and that the flow cross-section for the adsorption material between the feed region and the discharge region is at least substantially the same size. Such a configuration ensures a uniform flow rate of the adsorption material through the first device.

[0016] Alternatively, however, it can also be provided that the feed elements and the discharge elements are each identically designed, at least in themselves, and that the flow cross-section for the adsorption material increases or decreases between the feed area and the discharge area and / or that an alignment of the feed elements and / or discharge elements deviates from the horizontal. Such a configuration causes a change in the flow velocity of the adsorption material in the direction of the longitudinal axis of the first device and can, for example, serve to effect an adjustment for optimal saturation of the adsorption material with carbon dioxide when the adsorption material is already saturated (in the lower area of ​​the first device) by increasing or decreasing the exposure time of the air to the adsorption material (depending on the flow average used).In contrast, grain dryers are generally designed for universal use, meaning they can generally dry different foods such as corn kernels or rapeseed. In contrast, the shaft-shaped housing of the system according to the invention serves only the purpose of loading a known adsorption material with carbon dioxide from the ambient air.

[0017] The shaft-shaped housing can therefore be further optimized compared to the state of the art in grain dryers. The distances between the air guide elements can change, particularly in the direction of fall / flow of the adsorption material. This means that in the upper area, where the adsorption material is completely discharged, a lot of air is available in order to fully load the carbon dioxide onto the adsorption material. This means that many feed elements per cubic meter of housing are possible and sensible. Further down, the adsorption material is almost completely loaded with carbon dioxide; a high flow of ambient air therefore means that it must be expected that the carbon dioxide will not be fully loaded onto the adsorption material, but that the air escaping from the housing will still contain residual amounts of carbon dioxide, e.g. 200 ppm carbon dioxide. This increases the power required to overcome the pressure difference during ventilating orThe airflow through the lower section of the housing is used, which cannot be fully utilized. Optimization therefore consists in either injecting less ambient air into the lower section by reducing local fan power, or varying the number and / or cross-sectional area of ​​the ambient air supply elements compared to other sections, particularly by providing fewer supply elements per unit volume of the housing in the lower section.

[0018] It may also be advantageous not to arrange the feed elements exactly horizontally, but rather, if a row is arranged as a plane, to tilt every second feed element (i.e., the second, fourth, sixth element, etc. of the plane) of the row downward in the direction of air flow, and optionally to tilt each intermediate feed element in the opposite direction. This achieves cross-mixing across the multitude of stacked planes of air guide elements, thus achieving a more even residence time distribution of the adsorbent in the air stream, so that more carbon dioxide can be achieved in a shorter time or with a reduced housing height.

[0019] In further development of the last proposals, it can be provided that the change in the flow cross-section is generated by a change in the number of supply elements and / or discharge elements in the levels.

[0020] In a preferred design of the feed elements and the discharge elements, they are each closed, in particular roof-shaped, on the side facing the feed area and open on the side facing the discharge area. This allows the adsorption material to flow around the cross-section of the feed and discharge elements without entering their cross-section.

[0021] Furthermore, the supply and discharge elements can be provided with a perforated sheet or be designed as a porous, gas-permeable body. An appropriate pore size should ensure that, as far as possible, no adsorption material enters the pores and thus clogs them.

[0022] It may also be possible to actively close the feed elements, for example by using panels to expose different surfaces on the feed elements.

[0023] Furthermore, it can be provided to combine individual feed elements with a water atomizer nozzle, in particular to position a water atomizer nozzle in or in front of the feed elements in the upper area of ​​the housing. This is particularly advantageous if the housing or system is to be installed in regions with very low relative humidity, such as deserts or arctic regions, since adsorption material such as Lewatit® VP OC 1065, in particular, requires a minimum relative humidity for optimal adsorption of carbon dioxide from the air. This humidification can also be operated intermittently or only during the day, for example.

[0024] Furthermore, the invention relates to a method for operating a system designed according to the invention as described so far, wherein ambient air is introduced into the housing via the supply elements, which, after releasing carbon dioxide to the adsorption material, is at least indirectly returned to the environment from the housing via the discharge elements. The method according to the invention is characterized in that an air movement with a flow through the adsorption material at a flow velocity is adjusted by a ventilation device and / or that the amount of carbon dioxide absorbed by the adsorption material is adjusted via a mass flow of the adsorption material through the housing of the first device.

[0025] In a preferred development of the method described so far, it is provided that the flow velocity is adjusted in such a way that the introduction of particles of the adsorption material into the discharge elements is avoided.

[0026] Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments of the invention and from the drawings.

[0027] Short description of the drawings

[0028] Fig. 1 shows a schematic representation of a plant for the reduction of carbon dioxide from the ambient air,

[0029] Fig. 2 shows a first device for adsorbing carbon dioxide from the ambient air of the plant according to Fig. 1 in a longitudinal section,

[0030] Fig. 3 a section in the direction lll-lll of Fig. 2 and

[0031] Fig. 4 is a view of a portion of the first device according to Fig. 3 to explain the arrangement and design of supply elements and discharge elements for ambient air.

[0032] Embodiments of the invention The same elements or elements with the same function are provided with the same reference numerals in the figures.

[0033] Figure 1 shows a highly simplified illustration of a system 100 for reducing carbon dioxide from the ambient air or the atmosphere. The system 100 comprises a first device 10 for adsorbing carbon dioxide from the ambient air using a pourable adsorption material 1. The adsorption material 1 is, for example, a zeolite or Lewatit® VPOC 1065.

[0034] The adsorption material 1 is fed into a feed area 12 of the first device 10 and removed from the first device 10 in a discharge area 14. For this purpose, a discharge element 16 in the form of a rotary valve or similar can be used, for example, which does not destroy or mechanically damage the adsorption material 1 during conveyance. The adsorption material 1 then passes via a pipeline system 17 by means of a conveying system 18 in the form of a pump, a vacuum conveyor, a tubular chain conveyor or similar into a second device 20, which is designed as a desorption device to chemically and / or physically treat the carbon dioxide-enriched adsorption material 1 such that the carbon dioxide is extracted from the adsorption material 1 and can be removed from the second device 20 according to arrow 22, for example to be (finally) stored by compression at a geological site.The adsorption material 1 treated in the second device 20 then passes by means of a further discharge element 23 and a conveying system 24, optionally after further chemical or physical processing, into the feed area 12 of the first device 10, so that a closed circuit for the adsorption material 1 is formed.

[0035] 2 and 3, the first device 10 comprises a preferably column- or silo-like housing 26 with an at least substantially vertically oriented longitudinal axis 28. The feed region 12 is preferably arranged in the roof region of the housing 26, and the discharge region 14 is arranged in the bottom region of the housing 26. Within the interior 30 of the housing 26, which, for example, has a constant cross-section when viewed in the direction of the longitudinal axis 28, the adsorption material 1 is conveyed by gravity from the feed region 12 to the discharge region 14. In order for the carbon dioxide from the ambient air to be effectively absorbed by the adsorption material 1, the air flows through the adsorption material 1 within the interior 30 of the housing 26 in a direction at least substantially perpendicular to the longitudinal axis 28, according to the flow arrows 32, 34 in the transverse direction to the housing 26.

[0036] A plurality of supply elements 36 and discharge elements 38 for the ambient air are arranged within the housing 26 of the first device 10. The supply elements 36, which are preferably tubular, serve to bring the air, which is introduced into the supply elements 36 at overpressure, for example by means of a ventilation device 40, into operative connection or contact with the adsorption material 1. The discharge elements 38 serve to take in the air after it has flowed through the adsorption material 1, i.e., after a reduction in the carbon dioxide content, and to release it back into the environment or atmosphere. If necessary, a further ventilation device 40 or an extraction device can be used for this purpose in order to specifically influence or control the flow of air through the interior space 30.

[0037] The feed elements 36 open at a first side wall 42 of the housing 26 and end at a distance or forming a gap 43 from a second side wall 44 of the housing 26 opposite the first side wall 42. In contrast, the discharge elements 36 open at the second side wall 44 of the housing 26 and end at a distance or forming a gap 45 from the first side wall 42 of the housing 26.

[0038] The number of feed elements 36 and discharge elements 38, which are each preferably identical in themselves, is preferably the same when viewed in the direction of the longitudinal axis 28 of the housing 26. Furthermore, the distances a between the feed elements 36 and between the discharge elements 38 are also preferably the same (Fig. 4).

[0039] 3 and 4, it can also be seen that the feed elements 36 and the discharge elements 38 of the respective plane are arranged offset from one another in a direction running perpendicular to the longitudinal axis 28, wherein the distance a between two feed elements 36 or two discharge elements 38 preferably corresponds approximately to the width b of a feed element 36 or a discharge element 38. Furthermore, the feed elements 36 or the discharge elements 38 of a plane are each aligned in alignment with the gaps between the discharge elements 38 or feed elements 36 arranged immediately above or below them.

[0040] In the embodiment shown in Fig. 4, the feed elements 36 and the discharge elements 38 each have a roof region 46 on the side facing the feed region 12 in order to cause the adsorption material 1 to flow past the feed elements 36 and the discharge elements 38. The cross section of the feed elements 36 and the discharge elements 38 is each open on the side facing the discharge region 14 in order to enable an unhindered outflow of the air from the feed elements 36 or an inflow of the air into the discharge elements 38, as is intended to be illustrated by the air guidance arrows 48 in Fig. 4. The arrows 49 are intended to illustrate the flow direction of the adsorption material 1. Furthermore, it can be seen from Fig. 4 that, viewed in the direction of the longitudinal axis 28, the individual levels of feed elements 36 and discharge elements 38 can directly adjoin one another or even overlap one another.

[0041] The feed elements 36 or the discharge elements 38 can, for example, contain a perforated plate 50 to prevent the entry of adsorption material 1 into the cross-section of the feed elements 36 or the discharge elements 38. Alternatively, it is also possible for the feed elements 36 or the discharge elements 38 to consist of an air-permeable material or of a porous material, which is nevertheless preferably covered, for example, by a separate cover element on the side facing the feed area 12, in order to prevent the pores from being directly exposed to the adsorption material 1, so that the pores are not clogged by the adsorption material 1.

[0042] The ventilation device(s) 40 adjust the flow velocity of the air as it flows through or around the adsorption material 1. In particular, this flow velocity should be selected such that suction of adsorption material 1 into the discharge elements 38 is avoided.

[0043] In order to influence the amount of carbon dioxide adsorbed by the adsorption material 1, it can also be provided to change the flow cross-section for the adsorption material 1 viewed in the direction of the longitudinal axis 28 of the housing 26. This can be achieved, for example, by changing the number of feed elements 36 and / or the discharge elements 38 viewed in the direction of the longitudinal axis 28 between the feed area 12 and the discharge area 14, i.e., increasing or decreasing them. Alternatively, it can also be provided to change the cross-section of the housing 26 between the feed area 12 and the discharge area 14, i.e., decreasing or increasing it. Furthermore, the duration of exposure of the ambient air to the adsorption material 1 can be adjusted by controlling the flow rate of the adsorption material 1 through the housing 26.This can be done, for example, by the amount removed at the discharge area 14, whereby the amount of adsorption material 1 removed per unit of time flows into the feed area 12.

[0044] The first device 10 described so far as well as the system 100 can be modified in many different ways without deviating from the inventive concept.

Claims

Claims 1. A plant (100) for reducing carbon dioxide from the ambient air, comprising a first device (10) for adsorbing the carbon dioxide from the ambient air using a pourable or free-flowing adsorption material (1) and a second device (20) for desorbing the carbon dioxide-enriched adsorption material (1) - wherein the second device (20) is designed as a device (20) separate from the first device (10), - wherein the first device (10) has a feed area (12) for feeding the adsorption material (1) and a discharge area (14) for discharging the carbon dioxide-enriched adsorption material (1) from the first device (10), - wherein the first device (10) has a preferably shaft-shaped housing (26) with an at least substantially vertically oriented longitudinal axis (28), o which is designed so that the adsorption material (1) passes from the feed area (12) into the discharge area (14) under the effect of gravity, o wherein preferably at least substantially horizontally arranged, tubular feed elements (36) for the air and at least substantially horizontally arranged, tubular discharge elements (38) for the air are arranged in the housing (26), o wherein the air can be supplied or discharged on opposite sides of the housing (26), and o wherein the supply and discharge elements (36, 38) each end on the side of the housing (26) facing away from them, forming a gap (43, 45).

2. Plant according to claim 1, characterized in that that the feed elements (36) and discharge elements (38) are each arranged in a plurality of planes running perpendicular to the longitudinal axis (28) of the housing (26), wherein planes with feed elements (36) and planes with discharge elements (38) alternate.

3. Plant according to claim 2, characterized in that the feed elements (36) and the discharge elements (38) of two superimposed planes are arranged offset from one another in a direction perpendicular to the longitudinal axis (28).

4. Plant according to one of claims 1 to 3, characterized in that the feed elements (36) and the discharge elements (38) are each identically designed, at least in themselves, and in that the flow cross-section for the adsorption material (1) between the feed region (12) and the discharge region (14) is at least substantially the same size.

5. Plant according to one of claims 1 to 3, characterized in that the feed elements (36) and the discharge elements (38) are each designed identically, at least in themselves, and in that the flow cross-section for the adsorption material (1) between the feed area (12) and the discharge area (14) changes, in particular increases or decreases, and / or in that an alignment of at least some of the feed elements (36) and / or the discharge elements (38) deviates from the horizontal.

6. Plant according to claim 5, characterized in that the change in the flow cross-section for the adsorption material (1) is effected by changing the number of feed elements (36) and / or discharge elements (38) in the planes.

7. Plant according to one of claims 1 to 6, characterized in that the feed elements (36) and the discharge elements (38) are each closed, in particular roof-shaped, on the side facing the feed area (12) and open on the side facing the discharge area (14).

8. Plant according to one of claims 1 to 7, characterized in that the feed elements (36) and the discharge elements (38) have a perforated plate (50) to prevent the entry of adsorption material (1) and / or are designed as porous, gas-permeable bodies.

9. A method for operating a system (100) designed according to one of claims 1 to 8, wherein ambient air is introduced into the housing (26) of the first device (10) via the supply elements (36), which ambient air, after releasing carbon dioxide to the adsorption material (1), is at least indirectly returned to the environment via the discharge elements (38) from the housing (26), characterized in that a flow of air through the adsorption material (1) is adjusted by a ventilation device (40) and / or that the amount of carbon dioxide absorbed by the adsorption material (1) is adjusted via a mass flow of the adsorption material (1) through the housing (26).

10. Method according to claim 9, characterized in that the flow is adjusted in such a way that introduction of particles of the adsorption material (1) into the discharge elements (38) is avoided.

11. A computer program comprising instructions causing the system according to any one of claims 1 to 8 to carry out the method according to claim 9 or 10.

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