System and method for removing a gas component from a feed gas

Abstract

The invention relates to a system (100, 200) for removing a gas component from a feed gas (1). The system (100, 200) has an adsorption unit (110), which is designed to bring the feed gas (1) into contact with granular adsorption material (11, 12) so as to obtain a residual gas (2) in which the gas component is depleted as compared to the feed gas (1). The system (100, 200) also has a desorption unit (130) which is designed to regenerate the granular adsorption material (11, 12) by heating the granular adsorption material (11, 12) so as to obtain a desorbate (3) in which the gas component is enriched as compared to the feed gas (7). The system (100) is designed to heat a granular heating material (13, 14) and to heat the granular adsorption material (11, 12) by transferring heat from the granular heating material (13, 14) to the granular adsorption material (11, 12). The invention further relates to a method, to a computing unit, and to a computer program.

Description

[0001] R.415513

[0002] - 1 -

[0003] Description

[0004] title

[0005] Plant and method for removing a gas component from a feed gas

[0006] The present invention relates to a system and a method for removing a gas component from a feed gas, in particular carbon dioxide from air.

[0007] Background of the invention

[0008] To limit global warming, actively reducing the carbon dioxide content of the Earth's atmosphere, which has increased due to industrialization, is being discussed. One method being considered is "Direct Air Capture" (DAC), in which, in a first step, carbon dioxide is actively removed from the ambient air outdoors or via a ventilation system, for example in a building, and concentrated. This concentrated carbon dioxide can then be seguested in a second step, for example by injecting it into geological cavities.

[0009] To remove carbon dioxide from ambient air and concentrate it for subsequent seguestization, adsorptive processes, such as temperature swing adsorption, can be used. This process utilizes the temperature dependence of adsorption processes. An adsorbent, for example, granules of a suitable adsorbent material, is brought into contact with the air to be processed at a lower temperature level and thus becomes loaded with the carbon dioxide to be separated. The following can then be used: R.415513

[0010] - 2 -

[0011] The adsorption material can be largely freed of carbon dioxide by heating and thus regenerated.

[0012] For the continuous operation of conventional temperature swing adsorption (TSA) systems, at least two adsorption units are required so that one of the units is always flowing with the air being processed and thus used for carbon dioxide adsorption, while the other unit is undergoing regeneration. An alternative is a continuous cycle using a granular, circulating adsorption material.

[0013] The aim is to improve the relevant processes, in particular to increase their efficiency, throughput and dynamics.

[0014] Disclosure of the invention

[0015] Against this background, a system and a method for removing a gas component from a feed gas, in particular carbon dioxide from air, are proposed, comprising the features of the independent claims. Embodiments are the subject of the dependent claims and the following description.

[0016] The proposed system is used to remove a gas component from a feed gas. It includes an adsorption unit configured to bring the feed gas into contact with adsorption granules, resulting in a residual gas with a lower concentration of the gas component compared to the feed gas. In other words, the adsorption unit is configured to bring the feed gas into contact with adsorption granules so that the gas component is at least partially separated by the adsorption granules, thereby obtaining a residual gas with a reduced proportion of the gas component compared to the feed gas. R.415513

[0017] - 3 -

[0018] Furthermore, the system includes a desorption unit designed to regenerate the adsorption granules by heating them, thereby obtaining a desorbate with a higher concentration of the gas component compared to the feed gas. In other words, the desorption unit is designed to regenerate the adsorption granules by heating them, so that the separated gas component is removed from the adsorption granules, resulting in a desorbate with a higher concentration of the gas component compared to the feed gas.

[0019] The system is designed to heat a heating granulate and to heat the adsorption granulate by transferring heat from the heating granulate to the adsorption granulate.

[0020] Heat transfer processes involving the heating or cooling of granules are used as subprocesses in various types of process engineering plants. Embodiments of the present invention are used for the removal of carbon dioxide from gas mixtures, particularly from atmospheric air, and especially in connection with direct air capture. Other embodiments are also suitable for the removal of carbon dioxide from other gas mixtures, such as flue gases. The invention is therefore not limited to use in connection with direct air capture, but is fundamentally suitable for all gas mixtures that can be processed by adsorptive methods, especially carbon dioxide-containing gas mixtures.

[0021] In conventional processes, the granules are heated using heat transfer media. These media can be temperature-controlled liquids that transfer or absorb heat indirectly, either conductively or convectively, via suitable heat exchanger equipment. The granules and the heat transfer media do not come into direct contact. Superheated steam is also used for heating processes; it flows through the granules and transports the heat directly to the individual granules. Further equipment for R.415513

[0022] - 4 -

[0023] Heating is based on electrically heated conductive processes. The microwave technology also used requires water content in the granules. Depending on requirements, necessary temperature ranges, and to increase efficiency, the heat transfer processes are sometimes connected in series.

[0024] For the binding of carbon dioxide from ambient air, in particular, a continuous cycle process with a continuously circulating adsorption material in the form of granules appears to be a promising approach. For the desorption of carbon dioxide, it is necessary, among other things, to first heat the adsorption material to approximately 100°C under pressure in order to desorb the adsorbed carbon dioxide from the material and thereby regenerate it, and then to cool the adsorption material back down to below 50°C to prepare it for the adsorption of carbon dioxide again.

[0025] Depending on the adsorption material, the temperature level for adsorption can range from -30 to 50 °C, particularly from -10 to 30 °C, while the temperature level for desorption or regeneration can range from 50 to 150 °C, particularly from 80 to 120 °C. Adsorption can be carried out at a pressure level of, for example, 700 mbar absolute pressure (particularly during operation at an altitude of approximately 3000 m above sea level) to 1200 mbar absolute pressure (150 mbar overpressure relative to typical atmospheric pressure), particularly from 900 to 1100 mbar absolute pressure, and desorption at a sub-atmospheric pressure level of 10 to 200 mbar absolute pressure, particularly from 25 to 150 mbar absolute pressure.

[0026] Particularly with granules that have very low thermal conductivity and low specific heat capacity, as is typical in the application primarily considered here for carbon dioxide removal, where, for example, polystyrene is used as the adsorption material, the heating or cooling process can be very time-consuming or require correspondingly large heat exchange equipment. R.415513

[0027] - 5 -

[0028] Heat sources or sinks requiring a correspondingly high temperature difference to the granules result in poor energy efficiency. Direct contact and mixing with a liquid heating or cooling medium is not feasible in this case, as the desired chemical process would otherwise be impossible. For example, "Direct Air Capture" requires the release of gaseous carbon dioxide into a gaseous, inert environment.

[0029] In many applications, the granules are located at a sub-atmospheric pressure level, resulting in a very low convective heat conduction component between the granules. In the case of "Direct Air Capture," the desorption process begins as soon as the desorption temperature is reached at a given sub-atmospheric pressure level. Due to the temperature gradient caused by an external heat source within the working medium, complex inhomogeneities arise in the gas composition, which in turn can mutually impede heat and gas exchange processes. Therefore, controlled process management using conventional approaches is difficult.

[0030] In contrast, the designs proposed here demonstrate efficient alternative methods for the direct transfer of heat to or absorption of heat from a granular medium for process engineering processes, in particular adsorptive carbon dioxide removal processes, and furthermore, in particular "Direct Air Capture".

[0031] In embodiments of the invention, heat transfer to the adsorption granules can therefore occur more directly from the heated granules by conduction at the local granule contact points and by radiation with very short transfer paths, homogeneously throughout the entire granule mixture. Thus, maximum heat transfer efficiency can be achieved.

[0032] A key aspect of the proposed designs is a granular working medium (for "Direct Air Capture" e.g. polystyrene, here R.415513).

[0033] - 6 - generally referred to as "adsorption granules") are mixed directly with a similarly granular, previously conditioned heating or cooling medium (referred to here as "heating granules") to achieve maximum heat transfer to and from the adsorption granules. The heat transfer can thus occur directly through conduction at the local granule contact points and radiation with very short transmission paths, homogeneously throughout the entire working medium.

[0034] The heating granules differ from the adsorption granules, especially with regard to their chemical and / or physical properties, e.g., the material and heat capacity.

[0035] One group of configurations involves providing a heating unit designed to heat the heating granules in a state separated from the adsorption granules and then to mix them together to form a granule mixture, thereby facilitating heat transfer from the heating granules to the adsorption granules. Any type of heating method can be used for the heating granules, including those optimized for particularly rapid heating and those that do not require consideration of the temperature sensitivity of the adsorption granules during the heating process. Examples include the use of electric resistance heaters, heating plates, heating jackets, heating fans, and fired heaters.

[0036] In the first group of embodiments, a mixing unit can be provided, in particular, which is configured to mix the heating granules downstream of the heating unit and upstream of the desorption unit with the adsorption granules. Furthermore, a demixing unit can be provided, which is configured to separate the heating granules and the adsorption granules downstream of the desorption unit.

[0037] Such mixing and segregation can reduce the period during which the adsorption granules and the heating granules are mixed to R.415513

[0038] - 7 - The necessary time period can be limited, and the smaller quantity of heating granules to be heated by the heating unit allows for the use of smaller devices. By adding adjustable amounts of heating granules to the adsorption granules, the amount of heat transferred can be precisely controlled. The system therefore operates with exceptional flexibility, efficiency, and gentleness on the material.

[0039] In certain configurations, the mixing unit can have one or more screw conveyors and / or the demixing unit can be configured for gravity-based demixing, size-based demixing, or a combination thereof. Appropriate mixing and separation processes enable efficient and rapid separation, which, in the case of mixing, is particularly meterable and flexible.

[0040] In embodiments of the present invention, the separation unit can be configured to carry out a drum sieving process. In particular, it can be configured to supply a desorption gas to the drum sieving process, which absorbs and removes the desorbate. This gas can be, in particular, an inert gas such as nitrogen. This allows for a particularly advantageous supply of the inert desorption gas through the gas-permeable sieve wall to the adsorption granules, so that the desorption process can be carried out essentially simultaneously with the segregation and with particular efficiency.

[0041] In a second group of embodiments, a heating unit is provided which is designed to heat the heating granules in a state mixed with the adsorption granules. The heating unit can, in particular, be designed as an induction heating unit. Such embodiments do not necessarily require mixing and segregation of the adsorption and heating granules, but they do have certain limitations regarding the heating methods.

[0042] In embodiments of the present invention, the heating granules have a lower affinity for the gas component and a higher thermal conductivity R.415513

[0043] - 8 - as the adsorption granules. Advantageously, the gas component does not adsorb to the material of the heating granules in any significant way and therefore does not interfere with adsorption and desorption.

[0044] In embodiments of the present invention, the adsorption granules can, in particular, comprise an aromatic polymer, especially polystyrene, and / or the heating granules can, in particular, comprise a metal-based material, especially an alloy containing iron, aluminum, and / or copper. The heating granules can also, particularly for heating by inductive methods, comprise a carbon-containing material such as carbon fibers. The heating granules can be selected to exhibit optimized heat conduction and storage properties.

[0045] The proposed method for removing a gas component from a feed gas comprises an adsorption step in which the feed gas is brought into contact with an adsorption granulate, resulting in a residual gas depleted of the gas component compared to the feed gas, and a desorption step in which the adsorption granulate is regenerated by heating the adsorption granulate, resulting in a desorbate enriched with the gas component compared to the feed gas, wherein the method comprises heating a heating granulate and carrying out the heating of the adsorption granulate by transferring heat from the heating granulate to the adsorption granulate.

[0046] For further features and advantages of the proposed method, which in particular can have configurations that can be carried out using all the plant variants described here, reference is made to the explanations above, as these can apply equally to the proposed method.

[0047] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawing. R.415513

[0048] - 9 -

[0049] The invention is schematically illustrated in the drawing using an exemplary embodiment and is described below with reference to the drawing.

[0050] Brief description of the drawings

[0051] Figure 1 shows a system according to one configuration.

[0052] Figure 2 shows a system according to one design in partial view.

[0053] embodiment(s) of the invention

[0054] The embodiments described below are provided solely to assist the reader in understanding the claimed and previously explained features. They represent only representative examples and are not intended to be considered exhaustive or limiting with regard to the features of the invention. It is understood that the advantages, embodiments, functions, features, structures, and / or other aspects described above and below are not to be considered limitations of equivalents to the claims, and that other embodiments may be used and modifications made without deviating from the scope of the claimed invention.

[0055] Different embodiments of the invention may include, feature, consist of, or essentially consist of further advantageous combinations of the described elements, components, features, parts, steps, means, etc., even if such combinations are not specifically described herein. Furthermore, the disclosure may include other inventions that are not currently claimed but may be claimed in the future, particularly if they are within the scope of the independent claims.

[0056] Explanations relating to devices, apparatus, arrangements, systems, etc. according to embodiments of the present invention may be found in R.415513

[0057] - 10 - also apply to procedures, processes, methods, etc. according to the embodiments of the present invention and vice versa. Identical, functionally equivalent, structurally identical or comparably constructed elements, process steps, etc., may be indicated with identical reference numerals.

[0058] The following explanations and definitions relating to some fundamental aspects of the invention may apply to all or part of the embodiments presented here, and the explanation of certain aspects relating to only one part or one of the embodiments should not be understood to mean that these aspects cannot also be realized with other or all embodiments, insofar as technically possible and sensible.

[0059] Component mixtures (hereinafter referred to as "gases") can, in the terminology used here, be enriched or depleted of one or more components, these terms referring to a corresponding concentration in another component mixture (the original mixture) from which the component mixture was obtained. In the terminology used here, a component mixture is "enriched" if it contains at least 1.1 times, 1.5 times, 2 times, 5 times, 10 times, 100 times, or 1,000 times the concentration of a corresponding component, and "depleted" if it contains at most 0.9 times, 0.5 times, 0.1 times, 0.01 times, or 0.001 times the concentration of a corresponding component relative to the original mixture.

[0060] In the terminology used here, a component mixture is "derived" from, "formed" from, or "obtained" using a starting mixture if it contains at least some components present in or obtained from the starting mixture. A component mixture derived or formed in this sense can be obtained from the starting mixture by separating or diverting a partial stream or one or more components, enriching or depleting one or more components, or by chemical or physical means. R.415513

[0061] - 11 -

[0062] The conversion of one or more components, heating, cooling, pressurizing, and the like are used to obtain or form them.

[0063] The conjunction "and / or," when used in a list before the last item, should be understood to mean that all previously mentioned terms in the list can be combined with each other in any way. In other words, "A, B and / or C" means "A and / or B and / or C" or "at least one of the elements A, B, C in any combination."

[0064] Figure 1 shows a simplified schematic illustration of a system according to an embodiment of the present invention, and is generally designated by 100.

[0065] Figure 1 has been greatly simplified in many respects to better and more clearly illustrate the core idea of ​​the measures proposed here. For example, further process flows, valves, pipes, drives, control and regulating units, further processing units, etc., are omitted from the illustration, without this limiting the scope of the disclosure.

[0066] The system 100 serves to remove a gas component from a feed gas, in particular to remove carbon dioxide from air, and furthermore specifically for so-called "direct air capture." Its central component is an adsorption unit 110, which is designed to bring a feed gas 1 (illustrated by a fine dashed arrow) into contact with an unloaded or regenerated adsorption granule 11, resulting in a residual gas 2 (illustrated by a coarse dashed arrow) that is depleted of the gas component compared to the feed gas 1. The adsorption can be carried out based on principles known per se. The adsorption granule 11 is loaded with the gas component, which adheres to the adsorption granule. For clarity, the loaded adsorption granule is designated 12 in Figure 1.

[0067] Furthermore, a desorption unit 130 is provided, which is designed to desorption the adsorption granules 12 loaded with the gas component while obtaining an R.415513

[0068] - 12 - regenerate the desorbate 3 enriched with the gas component compared to the feed gas 1 by heating. Regeneration thus takes place by increasing the temperature, whereby a suitable, in particular inert, desorption gas 4 can also be used for the uptake and removal of the desorbate 3.

[0069] The proposed system provides for heat transfer to the adsorption granules 12 using another granule, referred to here as "heating granules." For this purpose, a mixing unit 120 is provided, which is configured to mix the adsorption granules designated 14, heated in a heating unit 150, downstream of the heating unit 150 and upstream of the desorption unit 130, with the adsorption granules 12 to form a granule mixture 16. The granule mixture 16 is then fed to the desorption unit 130. A granule mixture, designated 17 for clarity, is taken from the desorption unit 130. This mixture comprises the regenerated adsorption granules 11 and appropriately cooled heating granules 13.

[0070] Downstream of, or integrated into, the desorption unit 130, a demixing unit 140 is provided, which is designed to separate the heating granules 13 and the adsorption granules 11 from each other in the granule mixture 17 downstream or in the desorption unit 130. The adsorption granules 11 can then be returned to the adsorption unit 110 and the heating granules 13 can be reheated in the heating unit 150.

[0071] Figure 2 illustrates a system according to a further embodiment of the invention in the form of a schematic partial representation and is designated overall by 200. In the representation of Figure 2, the adsorption unit 110 and all material flows have been omitted. A mixing unit 120 and a demixing unit 140 may be provided, but this is not required.

[0072] In the system 200, a granular mixture 18 of heating and adsorption granules is guided in a, for example, tubular volume 170 and heated from a first temperature level T1 to R.415513 by means of a heating device 16.

[0073] - 13 - a second temperature level T2 is heated. An enlarged section 210 illustrates granules 12a of the adsorption granules 12 and granules 14a of the heating granules 14. The heating unit 160 comprises a voltage source 161 designed to provide an alternating electric field. The alternating electric field is illustrated with corresponding field lines. By heating the heating granules 14, this heat can be transferred particularly efficiently to the adsorption granules 12, as illustrated in section 210 with radially outward-pointing arrows. The granule mixture 18 can then be fed into a suitable desorption unit 13.

Claims

R.415513 - 14 - Claims 1. A system (100, 200) for removing a gas component from a feed gas (1), comprising: an adsorption unit (110) configured to bring the feed gas (1) into contact with an adsorption granulate (11, 12) while obtaining a residual gas (2) depleted of the gas component compared to the feed gas (1), and a desorption unit (130) configured to regenerate the adsorption granulate (11, 12) by heating the adsorption granulate (11, 12) while obtaining a desorbate (3) enriched with the gas component compared to the feed gas (7), wherein the system (100) is configured to heat a heating granulate (13, 14) and to heat the adsorption granulate (11, 12) by transferring heat from the heating granulate (13, 14) to the adsorption granulate (11, 12). 12) to carry out.

2. System (100) according to claim 1, comprising a heating unit (150) which is configured to heat the heating granules (13, 14) in a state separated from the adsorption granules (11, 12).

3. System (100) according to claim 2, comprising a mixing unit (120) configured to mix the heating granules (13, 14) downstream of the heating unit (150) and upstream of the desorption unit (130) with the adsorption granules (11, 12), and a demixing unit (140) configured to demix the heating granules (13, 14) and the adsorption granules (11, 12) downstream of the desorption unit (130).

4. Plant (100) according to claim 3, wherein the mixing unit (120) has one or more screw conveyors and / or the demixing unit (140) for R.415513 - 15 - gravity-based segregation, size-based segregation or a combination thereof is set up.

5. Plant (100) according to claim 4, wherein the mixing unit (140) is configured to carry out a drum sieving process and is in particular configured to supply a desorption gas to the drum sieving process for the absorption and removal of the desorbate (3).

6. System (200) according to one of the preceding claims, comprising a heating unit (160) which is configured to heat the heating granules (13, 14) in a state mixed with the adsorption granules (11, 12).

7. System (100, 200) according to one of the preceding claims, wherein the heating unit (160) is designed as an induction heating unit (160).

8. System (100, 200) according to one of the preceding claims, wherein the heating granules (13, 14) have a lower affinity for the gas component and a higher thermal conductivity than the adsorption granules (11, 12).

9. System (100) according to one of the preceding claims, wherein the adsorption granules (11, 12) comprise an aromatic polymer, in particular polystyrene, and / or the heating granules (13, 14) comprise a metal-based material, in particular an alloy containing iron, aluminium and / or copper, and / or a carbon-containing material.

10. Method for removing a gas component from a feed gas (1), comprising: an adsorption step in which the feed gas (1) is brought into contact with an adsorption granulate (11, 12) while obtaining a residual gas (2) that is depleted of the gas component compared to the feed gas (1), and R.415513 - 16 - a desorption step in which the adsorption granules (11 , 12) are regenerated by heating the adsorption granules (11 , 12) while obtaining a desorbate (3) enriched in the gas component compared to the feed gas (7), wherein the process comprises heating a heating granule (13, 14) and carrying out the heating of the adsorption granules (11 , 12) by transferring heat from the heating granules (13, 14) to the adsorption granules (11 , 12).

11. Method according to claim 10, comprising: heating the heating granules (13, 14) in a state separated from the adsorption granules (11, 12), in particular by means of a heating unit (150).

12. Method according to claim 11, comprising: mixing the heating granules (13, 14) downstream of the heating unit (150) and upstream of the desorption unit (130) with the adsorption granules (11, 12), in particular by means of a mixing unit (120), and separating the heating granules (13, 14) and the adsorption granules (11, 12) downstream of the desorption unit (130), in particular by means of a separation unit (140).

13. Method according to one of claims 10 to 12, comprising: heating the heating granules (13, 14) in a state mixed with the adsorption granules (11, 12), in particular by means of an induction heating unit (160).

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