Temperature-change adsorption of co2

Abstract

The invention relates to sorption material comprising at least one zeolite with at least one alkaline earth metal ion or transition metal ion. The invention also relates to a method for producing the sorption material, a method for carbon dioxide sorption and the use of the sorption material.

Description

[0001] Description

[0002] “Low-temperature cycling adsorption of CO2”

[0003] The invention relates to a sorption material, a process for producing a sorption material, the use of the sorption material and a process for sorbing carbon dioxide.

[0004] Carbon dioxide emissions into the atmosphere are currently considered a major driver of climate change. Carbon capture and storage (CCS) technologies are efficient and effective methods for reducing carbon dioxide emissions into the atmosphere.

[0005] Common methods for capturing carbon dioxide include absorption, adsorption, membrane-based systems, electrochemical separation, and cryogenic separation. The absorption of carbon dioxide in an aqueous solvent can be used to purify exhaust gases from power plants and industrial facilities.

[0006] Direct air capture (DAC) is increasingly seen as an important technology to slow global warming and thus limit the impacts of climate change (Smith, SM; Geden, O.; Nemet, GF; Gidden, MJ; Lamb, WF; Powis, C.; Bellamy, R.; Callaghan, MW; Cowie, A.; Cox, E.; et al. The State of Carbon Dioxide Removal - 1st Ed.; 2023).

[0007] This goal can be achieved through the development of new materials and energy-efficient concepts for capturing carbon dioxide from the air at minimal energy costs.

[0008] Carbon dioxide sorption is usually achieved using suitable sorption materials that can adsorb and desorb carbon dioxide effectively. However, such sorption materials often exhibit a certain instability toward other compounds present in the environment and / or prefer the adsorption of, for example, water over the adsorption of carbon dioxide. Another common problem with the desorption of carbon dioxide from sorption materials is the high temperature required for desorption. This can cause damage to the sorption material and / or require a high energy input.

[0009] The object of the present invention is to provide a sorption material which at least partially overcomes the above-mentioned disadvantages.

[0010] Furthermore, it is an object of the present invention to provide a process for producing a sorption material which at least partially overcomes the above-mentioned disadvantages.

[0011] Furthermore, it is an object of the present invention to provide a process for the sorption of carbon dioxide which at least partially overcomes the above-mentioned disadvantages.

[0012] This object is achieved by the sorption material according to the invention according to claim 1, the method according to claim 4 and the method according to claim 12.

[0013] Further advantageous embodiments of the invention emerge from the subclaims and the following description of preferred embodiments of the present invention.

[0014] A sorption material according to the invention comprises at least one zeolite with at least one alkaline earth metal ion or transition metal ion. Preferably, the alkaline earth metal ion and the transition metal ion are ions that replace the original ion.

[0015] Zeolites containing at least one alkaline earth metal ion or transition metal ion are also referred to herein as modified zeolites. Zeolites that do not contain an exchanged alkaline earth metal ion or transition metal ion are accordingly referred to herein as unmodified.

[0016] The approach described here is based on the use of a narrow temperature window for the adsorption and subsequent desorption (capture) of carbon dioxide from the air. Here, H-ZSM-5 zeolite and ion-exchanged H-ZSM-5 are used for measurements at low temperature swings, with the adsorption measurements being carried out at 5°C and the subsequent desorption in the range between 50°C and 80°C, which is significantly lower than the temperature windows used in the state of the art for the adsorption and desorption of other materials (Hedin, N.; Andersson, L.; Bergstrom, L; Yan, J. Adsorbents for the post-combustion capture of CO2 using rapid temperature swing or vacuum swing adsorption. Applied Energy 2013, 104, 418-433. DOI: 10.1016 / j.apenergy.2012.11.034; Mason, JA; Sumida, K.; Herrn, ZR; Krishna, R.; Long, JR Evaluating metal-organic frameworks for post-combustion carbon dioxide capture via temperature swing adsorption.Energy & Environmental Science 2011, 4 (8). DOI: 10.1039 / c1ee01720a; Ntiamoah, A.; Ling, J.; Xiao, P.; Webley, PA; Zhai, Y. CO2 Capture by Temperature Swing Adsorption: Use of Hot CO2-Rich Gas for Regeneration. Industrial & Engineering Chemistry Research 2016, 55 (3), 703-713. DOI: 10.1021 / acs.iecr.5b01384; Raganati, F.; Chirone, R.; Ammendola, P. CO2 Capture by Temperature Swing Adsorption: Working Capacity As Affected by Temperature and CO2 Partial Pressure. Industrial & Engineering Chemistry Research 2020, 59 (8), 3593-3605. DOI: 10.1021 / acs.iecr.9b04901).

[0017] The concept of this approach is based, among other things, on the use of physisorption phenomena of CO2 inside the H-ZSM-5, which allows for CO2 recovery at quite limited temperatures. Air or other gases, such as nitrogen, argon, or carbon dioxide, can be used as purge gas for desorption.

[0018] A sorption material can be understood as a compound that can adsorb and preferably also desorb a substance. In a preferred embodiment, the substance that is adsorbed and preferably also desorbed is carbon dioxide.

[0019] The zeolite can be one type of zeolite or different types.

[0020] Zeolite can be classified according to its pore size and / or specific surface area. Examples of zeolites are zeolite 13X, ZSM-5, zeolite 5A, zeolite 4A, zeolite 3A, etc.

[0021] The zeolites can have a defined particle size. Preferably, the zeolites have a size of 1 to 8 mm, more preferably 1 to 5 mm, and even more preferably 2 to 4 mm. The use of zeolites in powder form is also possible.

[0022] In one embodiment, the alkaline earth metal is selected from the group consisting of calcium, magnesium, barium, beryllium, and strontium. Preferably, the alkaline earth metal is calcium. In another embodiment, the transition metal ion is zinc. In further embodiments, the transition metal ion is selected from the group consisting of platinum, palladium, tin, cobalt, manganese, iron, nickel, and copper.

[0023] Furthermore, the present invention relates to a process for producing a sorption material as described herein, comprising the steps:

[0024] - Preparing zeolite powder,

[0025] - suspending the zeolite powder, and

[0026] - Mixing the suspension of zeolite powder with an alkaline earth metal salt solution or a transition metal salt solution.

[0027] In a process according to the invention, zeolite powder is first introduced. The zeolite powder can be a zeolite as described herein. For example, the zeolite powder can be selected from the group consisting of ZSM-5, 13X zeolite, 5A zeolite, 4A zeolite, and 3A zeolite.

[0028] The zeolite powder is then suspended. Suspension is preferably carried out in a suitable solvent. The solvent can be a polar solvent, for example, water.

[0029] In a further process step, the zeolite powder suspension is mixed with an alkaline earth metal salt solution or a transition metal salt solution. For this purpose, a solution of the alkaline earth metal salt solution or the transition metal salt solution is first prepared. The solution is also prepared in a suitable solvent. The solvent can be a polar solvent. For example, the solvent can be water.

[0030] The alkaline earth metal salt solution can be a common alkaline earth metal salt solution known in the art. In one embodiment, the alkaline earth metal salt solution is selected from the group consisting of calcium chloride, magnesium chloride, strontium chloride, barium chloride, and beryllium chloride. Preferably, the alkaline earth metal salt solution is calcium chloride.

[0031] The transition metal salt solution can be a common transition metal salt solution known in the art. In one embodiment, the transition metal salt solution is selected from the group consisting of zinc chloride, platinum chloride, palladium chloride, tin chloride, cobalt chloride, manganese chloride, iron chloride, nickel chloride, and copper chloride.

[0032] The zeolite powder and the alkaline earth metal salt solution or the transition metal salt solution are preferably mixed together in the range between 1:30, more preferably in the range 1:20, even more preferably in the range 1:15.

[0033] In one embodiment, a process according to the invention further comprises the step of heating the mixture of the suspension of the zeolite powder with the alkaline earth metal salt solution or the transition metal salt solution.

[0034] The heating can take place at a temperature > 30°C, preferably 50°C, more preferably > 50°C.

[0035] The heating can be carried out for a specific time. For example, the heating can be carried out for at least 8 hours, preferably at least 12 hours, more preferably at least 16 hours, and even more preferably at least 24 hours.

[0036] By a process according to the invention, the metal ions in zeolites can be exchanged by transition metal ions or alkaline earth metal ions.

[0037] Furthermore, the present invention relates to a sorption material produced by a process as described herein.

[0038] The present invention further relates to the use of a sorption material as described herein for adsorbing carbon dioxide. Preferably, the sorption material is also suitable for desorbing carbon dioxide.

[0039] A sorption material according to the invention can be used in a DAC (direct air capture) process, in the chemical industry, in the petroleum industry, and in CO2 emitters (aluminum smelters, cement plants, power plants, etc.). CO2 obtained in this way can, for example, be used generally as a raw material in chemical synthesis or for the production of e-fuels. Furthermore, the present invention relates to a process for the sorption of carbon dioxide, comprising the step:

[0040] - Adsorption of carbon dioxide by contacting at least one sorbent material as described herein with carbon dioxide.

[0041] The process for sorption of carbon dioxide can be a DAC process.

[0042] In a process according to the invention, the sorption material can be brought into contact with a gaseous medium comprising carbon dioxide in a suitable device. The gaseous medium can be atmospheric air, ambient air, exhaust gases, gases from point sources, etc.

[0043] A method according to the invention may further comprise the step of desorbing carbon dioxide by heating the at least one sorption material with adsorbed carbon dioxide.

[0044] The heating can be carried out to a temperature >30°C, preferably >50°C, more preferably >80°C.

[0045] Sorption materials according to the invention preferably exhibit high selectivity towards CO2 compared to H2O. When used, for example, in the sorption of carbon dioxide, as in DAC processes, this can result in more CO2 being adsorbed than H2O. This is particularly interesting in the preparation of process streams (e.g., pre-drying) for CO2 adsorption processes, as well as in the regeneration of sorption materials.

[0046] Sorption materials according to the invention also exhibit good robustness and thus long-term use in various sorption processes may be of interest.

[0047] In particular, sorption materials according to the invention can desorb adsorbed substances (e.g., CO2) at low temperatures. For example, the adsorbed substance (e.g., CO2) can be desorbed at temperatures between 30°C and 100°C, preferably between 40°C and 90°C, more preferably between 50°C and 80°C. In processes such as DAC (direct air capture) processes, a purge stream (e.g., N2, Ar, CCh, etc.) can be used to regenerate the sorption materials and remove CO2 at low temperatures, thus saving energy.

[0048] Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which:

[0049] Fig. 1 shows a schematic diagram of the adsorption setup used in the dynamic adsorption measurement for direct air separation from air (with 400 ppm CO2) and in the absence or presence of atmospheric humidity,

[0050] Fig. 2 schematically shows the steps of the process (adsorption, saturation, and desorption),

[0051] Fig. 3a and 3b show the dynamic sorption measurements for direct air separation from humid air (with 400 ppm CO2) on the zeolites (Fig. 3a: adsorption (5 °C), Fig. 3b: desorption (80 °C)),

[0052] Fig. 4 the single gas adsorption isotherms of the zeolites,

[0053] Fig. 5 shows the mass profile of the relevant masses of a mass spectrometer during the measurement of four sorption cycles on ZSM-5 at a slight temperature change (adsorption phases are shown in boxes with a solid line (5 °C), desorption phases in boxes with a dashed line (50 °C) and the addition of water during adsorption (0.03 ml / h) is shown in a black line).

[0054] Fig. 6 schematically shows a basic structure of a zeolite,

[0055] Fig. 7 schematically shows a process for producing a sorption material, and

[0056] Fig.8 shows schematically a process for the sorption of carbon dioxide.

[0057] Fig. 1 shows a schematic representation of an adsorption setup 100 that can be used in dynamic adsorption measurements for direct air separation from air (with 400 ppm CO2) and in the absence or presence of atmospheric humidity. The adsorption setup 100 has a gas flow 101 (air, 1 bar, 400 ppm CO2). In addition to air, the gas flow 101 also includes H2O. The gas flow is passed through a device comprising sorption particles 102 (e.g., a tubular reactor). The device can have a diameter of 2.5 cm. The sorption particles adsorb CO2 and H2O. The CO2 and H2O are then desorbed, and the resulting mass flow is analyzed in a mass spectrometer 103.

[0058] 1 . Description of the synthesis

[0059] 1.1 Syntheses of ion-exchanged X / ZSM-5 (X: Ca; Mg; Zn)

[0060] Weighing 6 g ZSM-5 zeolite

[0061] 0.17g CaCh in 100 g distilled. H2O 0.24g MgCh in 100 g distilled. H2O 0.13g ZnCh in 100 g distilled. H2O

[0062] ZMS-5 zeolite powder was dispersed in distilled water (in a beaker with a lid) for 30 minutes in an ultrasonic bath. The suspension (in a round-bottom flask) was heated to 80 °C (water bath). The respective metal salt was dissolved in distilled water (metal solution), and the solution was transferred to a dropping funnel. The metal solution was added dropwise to the zeolite suspension over a period of approximately 30 minutes. The mixture was left to stir overnight at 80 °C (24 hours). The X-ZMS-5 was filtered (pleated filter) and rinsed 5 times with distilled water. The collected precipitate was dried overnight in a vacuum drying oven at 80 °C.

[0063] 1.2 Analysis of the manufactured materials

[0064] The ion-exchanged ZSM-5 and the untreated ZSM-5 were analyzed for their surface area and pore volume using the BET method. The BET determination was carried out according to DIN ISO 9277:2003-05 of May 2003 (Determination of the specific surface area of ​​solids by gas adsorption using the BET method (ISO 9277:1995 of May 1995)). The results are presented in Table 1.

[0065] It is evident that ion exchange has only a very slight effect on the surface of the zeolite. The volumes of the micropores also remain constant.

[0066] Table 1 : Results of the BET investigations on the prepared ZSM-5 materials.

[0067] 2. Dynamic measurement of CCh deposition

[0068] 2.1. The adsorption / desorption structure

[0069] The setup for the dynamic adsorption / desorption measurements consists of the following parts (as shown schematically in Fig. 1):

[0070] - Gas supply unit for supplying the adsorption mixture for the measurements and the gas used for drying.

[0071] Tubular reactor in which the sorption material is packed.

[0072] - Analysis unit (mass spectrometer) connected to the outlet of the tubular reactor for analysis.

[0073] - Water saturator to humidify the adsorption gas (air) for realistic adsorption measurements.

[0074] 2.2. Experimental approach:

[0075] To evaluate the adsorption properties of the modified zeolitic materials, the following sequence was used (adsorption, saturation and desorption are shown in Fig. 2):

[0076] The sample was loaded into the tubular microreactor and rigorously dried under an Ar flow to desorb all pre-adsorbed water and CO2.

[0077] The reactor temperature was reduced to 5 °C, at which the desorption measurements were carried out.

[0078] The adsorption was carried out until saturation, with the CO2 content at the reactor outlet being 400 ppm.

[0079] After saturation, the desorption step (collection of CO2) was carried out at 120 °C under an Ar flow.

[0080] The previous step was carried out until no more CO2 was found in the escaping gas stream.

[0081] As an alternative to an Ar stream, an N2 stream can also be used.

[0082] 3. Results of CO2 adsorption and desorption for ion-exchanged ZSM-5 zeolites

[0083] 3.1. Dynamic sorption measurements

[0084] The materials ZSM-5, Ca-ZSM-5, Mg-ZSM-5 and Zn-ZSM-5 were prepared as described in

[0085] 2.2 Experimental approach described under dynamic conditions for their adsorption capacity for CO2 and water, and thus for their adsorption selectivity towards water. The sorption curve is shown in Figs. 3a and 3b, and the adsorption amount is given in Table 2.

[0086] It was found that:

[0087] The measurements show a fast CC>2 adsorption of the materials, with the uptake of CO2 being highest for Ca-ZSM-5.

[0088] Table 2: CO2 uptake in the dynamic measurements.

[0089] The modified zeolites exhibit rapid CO2 adsorption and desorption at slightly elevated temperatures. The addition of water during low-temperature sorption cycles shows no effect on CCh adsorption. An efficient sorption cycle was achieved at a low temperature.

[0090] Furthermore, single-gas adsorption measurements were performed, as shown in Fig. 4, and compared with the CO2 uptake from the dynamic measurements. The CO2 uptake in the dynamic measurements is highlighted in a circle (see Table 2).

[0091] This makes it clear:

[0092] The Ca-ZSM-5 isotherm showed the highest CO2 adsorption at low partial pressures. Increasing the pressure in the isotherms leads to an equalization of the CO2 uptake.

[0093] The high CCh uptake of Ca-ZSM-5 in the dynamic measurements corresponds to the observation in the adsorption isotherms.

[0094] 3.2. Sorption cycles with small temperature changes

[0095] On the unmodified ZSM-5, successive sorption cycles of adsorption at

[0096] 5 °C adsorption in water-containing air and desorption in argon at 50 °C were performed, as shown in Fig. 5. The CO2 uptake of the material during these cycles is summarized in Table 3. It can be seen that the CO2 uptake is constant over the measurement period over four cycles.

[0097] Table 3: CO2 uptake in successive sorption cycles as shown in Fig. 5.

[0098] Fig. 6 shows schematically the structure of a zeolite.

[0099] Fig. 7 schematically shows a method for producing a sorption material 200 comprising the steps:

[0100] - Preparing zeolite powder 204,

[0101] - Suspending 205 of the zeolite powder,

[0102] - Mixing 206 the suspension of the zeolite powder with an alkaline earth metal salt solution or a transition metal salt solution and

[0103] - optionally heating 207 the mixture of the suspension of the zeolite powder with the alkaline earth metal salt solution or the transition metal salt solution.

[0104] Fig. 8 schematically shows a process for the sorption of carbon dioxide 300. The process comprises the step of adsorbing carbon dioxide 308 by contacting at least one sorption material with carbon dioxide. Optionally, the desorption of carbon dioxide 309 is carried out by heating the at least one sorption material with adsorbed carbon dioxide.

[0105] List of reference symbols

[0106] Adsorption structure

[0107] Gas flow

[0108] Device comprising sorption particles

[0109] Mass spectrometer

[0110] Sorption material

[0111] Preparing zeolite powder

[0112] Suspend

[0113] Mix

[0114] Heat

[0115] Process for the sorption of carbon dioxide

[0116] Adsorption of carbon dioxide

[0117] Desorption of carbon dioxide

Claims

Patent claims 1. Sorption material comprising at least one zeolite with at least one alkaline earth metal or transition metal ion.

2. Sorption material according to claim 1, wherein the alkaline earth metal is selected from the group consisting of calcium, magnesium, barium, berrylium and strontium.

3. Sorption material according to claim 1, wherein the transition metal ion is zinc.

4. A process for producing a sorption material according to at least one of claims 1 to 3, comprising the steps: - Preparing zeolite powder, - suspending the zeolite powder, and - Mixing the suspension of zeolite powder with an alkaline earth metal salt solution or a transition metal salt solution.

5. The process of claim 4, wherein the zeolite powder is selected from the group consisting of ZSM-5, 13X zeolite, 5A zeolite, 4A zeolite and 3A zeolite.

6. The method of claim 4 or claim 5, wherein the alkaline earth metal salt solution is selected from the group consisting of calcium chloride, magnesium chloride, strontium chloride, barium chloride and beryllium chloride.

7. The process according to at least one of claims 4 to 6, wherein the transition metal salt solution is selected from the group consisting of zinc chloride, platinum chloride, palladium chloride; tin chloride, cobalt chloride, manganese chloride, iron chloride, nickel chloride, and copper chloride.

8. Process according to at least one of claims 4 to 7, wherein the ratio between zeolite powder and alkaline earth metal salt solution or transition metal salt solution is in the range between 1:

30.

9. The method according to at least one of claims 4 to 8, further comprising the step: - Heating the mixture of the suspension of the zeolite powder with the alkaline earth metal salt solution or the transition metal salt solution.

10. Sorption material produced according to at least one of claims 4 to 9.

11. Use of a sorption material according to at least one of claims 1 to 3, or 10 for the adsorption of carbon dioxide.

12. A process for the sorption of carbon dioxide comprising the step: - Adsorption of carbon dioxide by bringing at least one sorption material according to at least one of claims 1 to 3, or 10 into contact with carbon dioxide.

13. The method of claim 12, further comprising the step: - Desorption of carbon dioxide by heating the at least one sorption material with adsorbed carbon dioxide.

14. The method according to claim 13, wherein the heating is carried out to a temperature >30°C, preferably >50°C, more preferably >80°C.

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