Method and device for breaking down carbon dioxide

Abstract

The present invention relates to a method and device for transforming carbon dioxide (CO2) into its elements, C and O2, by means of the combined use of laser irradiation (4) and dielectric barrier discharge plasma (1) which are applied to high-melting-point ceramic or metallic substrate catalysts in a chamber (2). In this way, laser radiation increases the temperature only in the area in which it is applied, to the catalysts, in order for the emission plasma to reach a temperature close to 3400 K, capable of breaking down CO2, only in that area and not in the entire plasma reactor chamber.

Description

[0001]DESCRIPTION Method and device for decomposing carbon dioxide Technical sector The invention falls within the sector of chemical processes in general for reacting gaseous media, as well as apparatus specially adapted for this purpose, as well as in the sector of physical processes. More specifically, the invention relates to a method and equipment for decomposing carbon dioxide (CO2) into its elements. State of the art There is currently an emergency situation in the world, already scientifically confirmed in numerous publications, with evidence of climate change in which the human factor is decisive and is associated with greenhouse gas emissions from the combustion of fossil fuels.One of the possible solutions to mitigate this destructive phenomenon is the reduction of carbon dioxide (CO2) emissions from many industrial processes, which generate very high environmental and economic costs, both for society in general and for the industries involved, whose activity is vital to maintaining the present and future economic situation of our environment. In this regard, there are several important industries, such as the ceramics and cement industries, whose control of CO2 emissions is vital to maintaining their leadership position. Furthermore, there are passenger and freight transport modes whose contribution to greenhouse gas emissions accounts for a significant percentage of the total. Prominent among these are air and sea transport vehicles, which surpass other land freight transport modes, all based on technologies that use fossil fuels.Among the technologies under development for reducing carbon dioxide (CO2) emissions, those based on the use of plasmas to break chemical bonds stand out (Y. Yin et al., Phys. Chem. Chem. Phys., 2021, 23, 7974–7987). In principle, the selection of the plasma type is crucial to avoid recombination reactions that substantially reduce the efficiency of the breaking process towards desirable products. These can include C and O2, or organic products (alcohols and other synthetic fuels) and O2, for example. Apparently, according to these authors, the maximum breaking efficiency is obtained by combining a plasma with adequate emission with high temperatures, close to 3400 K.One of the most relevant problems when applying this new technology in industry is scaling up, since the results obtained in research laboratories suggest the existence of scaling limits that can only be overcome with new designs and innovative geometries, accompanied by complementary technologies to avoid high costs that prevent its large-scale implementation. The combination of plasmas based on dielectric discharge barriers with catalysts has already been verified, giving rise to a slight increase in the efficiency of breaking the CO2 molecule [RH Rad et al., Chemical Enginneering Journal 456 (2023) 141072; X. However, although this combination represents certain improvements, it is still not sufficient to achieve breakthrough objectives that can be scaled to an attractive industrial system from the perspective of process efficiency. Furthermore, the laser is a tool that, depending on its emission characteristics, can generate plasmas and local temperatures within the zone of maximum efficiency, as it allows the selection of the type of plasma and the local temperature at the interface with a suitable substrate, while offering spatial and temporal control unmatched by any other technology. Laser technology has also been used to promote phenomena in liquids, including the transformation of CO2 molecules into CO2. Therefore, there is a need to develop alternative technologies that can facilitate the scaling of these technologies, which are still largely experimental, at an affordable cost. In turn, these technologies would pave the way for the more than likely integration of the systems into large-scale installations, such as industrial chimneys and large ships. Explanation of the invention In order to achieve the proposed objectives mentioned in the previous section, the invention proposes a method for decomposing carbon dioxide, which has the characteristics of claim 1. It has been found that the laser is also very attractive for promoting greater efficiency in heterogeneous catalysis phenomena, activating the catalyst surface with the optimal wavelength for this purpose.For this reason, a new method has been developed and tested to decompose CO2 using refractory ceramics with electro and photocatalytic properties as a catalyst, to develop integrated dielectric barrier discharge (DBD) plasma devices, with geometries adapted to in-line laser scanning that facilitate maximum interaction with the gas flow to be transformed.In summary, the present invention is based on the premise of the combined use of laser irradiation on high melting point catalysts in a plasma reactor to decompose CO2 into C and O2; the integration of the laser in the plasma reactor makes it possible to avoid working at extremely high temperatures, since the laser radiation increases the temperature only in the area where it is applied, on the catalysts, such that the emission plasma reaches a temperature close to 3400 K, capable of achieving the decomposition of CO2, only in that area and not in the entire plasma reactor chamber. The method of the invention also allows the reduction of carbon dioxide CO2 into CO + 1 / 2 O2, through the combined use of laser and plasma irradiation on high melting point ceramic substrates.The invention also provides for the development of a device that allows CO2 molecules to be broken down into their elements, elemental Oxygen (O2) and Carbon (C), in various nanostructured forms. The latter are, in turn, proposed as high-added-value materials for functional applications on the surfaces of materials for numerous industrial uses. In this method, laser irradiation is produced with IR, Visible, or UV sources and using lasers emitting in pulsed mode, with pulse widths of nanoseconds (ns), picoseconds (ps), or femtoseconds (fs), or in continuous mode (cw). The plasma is produced by electrical discharge, microwaves, and other conventional mechanisms, and in various geometries based on DBD (Dielectric Barrier Discharge) technology and using plasma power supplies with direct current (DC) or alternating current (AC) input voltage.The output voltage can range from 100 V to 10 kV, the output frequency 1 kHz to 100 kHz, and the output power from 0.5 W to 10 kW, with one or multiple dielectric materials located between the electrodes, and a gas pressure of 100 Pa to 10 atmospheres. The type of plasma generated can be thermal (thermodynamic equilibrium) or non-thermal (non-thermodynamic equilibrium). Likewise, the use of noble gases, nitrogen, oxygen, carbon dioxide, hydrocarbons, water vapor, and combinations thereof is contemplated to generate the plasma. The catalysts can be supported on high-melting-point ceramic substrates. When manufactured with ceramic substrates, those containing oxides of zirconium, aluminum, titanium, barium, cerium, and other rare earths, as well as oxides of alkaline earth metals, transition metals, and Group 13 metals, have been selected.When the catalysts are metal oxides, they are preferably based on Ceria (cerium dioxide, CeO2) doped with one or more transition metal oxides (Scandium, Titanium, Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel, Copper and Zinc; Yttrium, Zirconium, Niobium, Molybdenum, Technetium, Ruthenium, Rhodium, Palladium, Silver and Cadmium; Hafnium, Tantalum, Tungsten, Rhenium, Osmium, Iridium, Platinum, Gold and Mercury) and / or group 13 oxides (Boron, Aluminum, Gallium, Indium, Thallium). If applicable, with co-catalysts or promoters of alkaline and / or alkaline earth metal oxides (Lithium, Sodium, Potassium, Rubidium, Cerium, Beryllium, Magnesium, Calcium, Strontium, Barium).In an alternative embodiment, the catalysts are a combination of two or more transition metal oxides (Scandium, Titanium, Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel, Copper and Zinc; Yttrium, Zirconium, Niobium, Molybdenum, Technetium, Ruthenium, Rhodium, Palladium, Silver and Cadmium; Hafnium, Tantalum, Tungsten, Rhenium, Osmium, Iridium, Platinum, Gold and Mercury) and group 13 oxides (Boron, Aluminum, Gallium, Indium, Thallium). If applicable, with promoters of alkaline metal oxides and / or alkaline earth metals (Lithium, Sodium, Potassium, Rubidium, Cesium, Beryllium, Magnesium, Calcium, Strontium, Barium). Regarding the laser, it can illuminate the surface of the ceramic substrate in flat or complex geometry, using conventional optics or a conventional beam movement system (galvanometric or polygonal scanner).In another embodiment, the laser exclusively illuminates a substrate with catalysts, this being of a ceramic nature and complemented by a plasma unit not coupled to the laser-irradiated catalyst. Description of the drawings In order to complement the description being made and in order to facilitate the understanding of the characteristics of the invention, a set of drawings is attached to this specification in which, for illustrative and non-limiting purposes, the following has been represented: Fig. 1 schematically represents a chamber (2) used to demonstrate the breakdown of CO2 by means of a combination of laser, DBD plasma and a metal oxide as a catalyst. Embodiment of the invention The device for decomposing carbon dioxide (CO2) into its elements, C and O2, comprises: a plasma reactor (1), a laser device (5) and ceramic substrates on which to apply the plasma and laser radiation (4), all integrated in a chamber (2).The plasma reactor (1) is of the dielectric barrier discharge (DBD) type, which is applied to a high melting point catalyst. The chamber is provided with windows (8) suitable for the transmission through them of laser radiation (4), as well as gas inlets (6) and outlets (7). If necessary, a vacuum pump that acts in said chamber (2) can also be connected. In said reactor (1), the plasma is produced by means of electric discharge, microwaves, or other mechanisms in various geometries, all of them based on dielectric barrier discharge (DBD) technology and using plasma power supplies with direct current (DC) or alternating current (AC) input voltage. Said plasma reactor (1) can have an output voltage between 100 V and 10 kV; an output frequency between 1 kHz and 100 kHz; and an output power between 0.5 W and 10 kW. Likewise, it can use one or multiple dielectric materials located between the electrodes.The laser device (5), integrated with the plasma reactor (1), employs IR, visible or UV sources, and emits in pulsed mode with nanosecond (ns), picosecond (ps) or femtosecond (fs) pulse widths. It can also emit in continuous mode (cw). The laser radiation (4) illuminates the surface of the catalytic substrate in planar or complex geometry, by using conventional optics or by means of a beam movement system using a galvanometric or polygonal scanner (9). The laser radiation (4) exclusively illuminates the surface of the catalytic substrate, complemented by a plasma unit not coupled to the laser-irradiated catalyst. The catalysts on the surface of the catalytic substrate can be of a ceramic nature. Catalysts based on high-melting ceramic substrates preferably contain oxides of zirconium, aluminum, titanium, barium, cerium and other rare earths, as well as alkaline earth and transition metals.Metal oxide catalysts are based on Ceria (cerium dioxide, CeO2) doped with one or more transition metal oxides and / or other metals. In an alternative embodiment, the catalysts are made up of a combination of two or more transition metal oxides and group 13 oxides, where appropriate, with alkaline and / or alkaline earth metal oxide promoters. The details of the substrates, catalysts and co-catalysts have been described in the previous section. The chamber (2) integrates a part of the plasma reactor (1), such that its windows (8) face a window (3) in said chamber (2), to which the laser radiation (4) from the laser device (5) is applied.The following describes an experiment aimed at comparing the selective breakdown of CO2 molecules using DBD plasma, DBD plasma combined with a catalyst, laser, laser combined with a catalyst, and the total combination of DBD plasma with a catalyst and laser. In all cases, the tests described correspond to a static situation in which the CO2 concentration is initially set and the change in composition is measured as a function of treatment (in time and area / volume affected). The experiments were carried out in a vacuum chamber, previously evacuated in several argon vacuum / pressure cycles, in order to reduce the oxygen pressure to a minimum. Inside the chamber (volume 10888 cm. 3) two fans were installed, one horizontal at the base of the chamber (vertical forced flow), and another at the exit through a window coupled to the gas meter used. A low-power DBD plasma unit was also located at the base of the chamber, also inside it. The laser was fixed to the top of the chamber, on the outside, and directly aligned with a window of similar size to that of the laser exit lens. After several vacuum cycles were performed in the chamber, it was filled with predetermined mixtures of Ar + CO2, until constant composition values ​​were reached. In a subsequent stage, plasma, plasma + catalyst, laser, laser + catalyst, and plasma + catalyst + laser treatments were performed independently, in order to determine the different transformation efficiencies in each case and depending on the treatment periods. Table 1 summarizes the results obtained. Table I.Comparative results obtained for CO2 reduction in % volume per minute and for several of the treatments performed. Where: P = plasma; PC = plasma + catalyst; PL ns = plasma + laser (ns); PL ns C = plasma + ns laser + catalyst; l fs C (fs) = fs laser + catalyst; l fsC (fs) = plasma + fs laser + catalyst. As can be seen from the data summarized in the table above, the most efficient processes for breaking up CO2 are achieved by combining the catalyst and a pulsed laser combined with DBDs plasma. The simultaneous use of the DBD plasma reactor prevents the reaction between the two elements from being reversed once CO2 has been transformed into its elements C and O2. It is hereby stated that the materials, shape, size and arrangement of the elements described may be modified, provided that this does not imply an alteration of the essential characteristics of the invention claimed below:

Claims

CLAIMS 1. A method for transforming carbon dioxide (CO2) into its elements C and O2, by the combined use of laser irradiation and dielectric barrier discharge (DBD) plasma over high melting point ceramic substrate catalysts applied in a chamber (2).

2. A method according to claim 1, wherein the laser irradiation is produced with IR, Visible, or UV sources and using lasers emitting in nanosecond (ns), picosecond (ps), or femtosecond (fs) pulse regimes, or in continuous mode (cw).

3. A method according to claim 1, wherein the plasma is produced by electrical discharge, microwaves, or other mechanisms, in various geometries based on dielectric barrier discharge (DBD) technology. 4.- Method according to claim 3, wherein the plasma is used with an output voltage between 100 V and 10 kV, an output frequency between 1 kHz and 100 kHz, and an output power between 0.5 W and 10 kW, using one or more dielectric materials located between the electrodes.

5. - Method according to claim 3, wherein the type of plasma generated is thermal (thermodynamic equilibrium) or non-thermal (non-thermodynamic equilibrium).

6. - Method according to claim 1, wherein ceramic substrates containing oxides of zirconium, aluminum, titanium, barium, cerium, and other rare earths, as well as oxides of alkaline earth, transition metals, and group 13 metals, are used as catalysts. 7.- Method according to claim 6, wherein the catalysts are metal oxides based on Ceria (cerium dioxide CeO2), doped with one or more transition metal oxides (Scandium, Titanium, Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel, Copper and Zinc; Yttrium, Zirconium, Niobium, Molybdenum, Technetium, Ruthenium, Rhodium, Palladium, Silver and Cadmium; Hafnium, Tantalum, Tungsten, Rhenium, Osmium, Iridium, Platinum, Gold and Mercury) and / or group 13 oxides (Boron, Aluminum, Gallium, Indium, Thallium). 8.- Method according to claim 1, wherein the catalysts are formed by a combination of two or more transition metal oxides (Scandium, Titanium, Vanadium,. Chromium, Manganese, Iron, Cobalt, Nickel, Copper and Zinc; Yttrium, Zirconium, Niobium, Molybdenum, Technetium, Ruthenium, Rhodium, Palladium, Silver and Cadmium; Hafnium, Tantalum, Tungsten, Rhenium, Osmium, Iridium, Platinum, Gold and Mercury) and group 13 oxides (Boron, Aluminum, Gallium, Indium, Thallium).

9. Method according to any of claims 7 or 8, wherein the catalysts are used with alkaline metal and / or alkaline earth metal oxide promoters (Lithium, Sodium, Potassium, Rubidium, Cesium, Beryllium, Magnesium, Calcium, Strontium, Barium). 10.- Method for decomposing carbon dioxide (CO2) into CO and O2, by the combined use of laser and plasma irradiation on high melting point ceramic substrates, applied in a continuous flow reactor. 11.- Device for decomposing carbon dioxide (CO2) into its elements, C and O2, comprising: - a dielectric barrier discharge (DBD) type plasma reactor (1), which is applied on a high melting point catalyst,said plasma reactor (1) being integrated inside a chamber provided with windows (8) suitable for the transmission of laser radiation (4), and gas inlets (6) and outlets (7); - a laser device (5), integrated with the plasma reactor (1); - high melting point ceramic substrate catalysts, on which the plasma and laser radiation (4) are applied, located in a window (3) of a chamber (2); and - a chamber (2), around the plasma reactor (1), provided with a window (3) in which the laser radiation (4) of the laser device (5) is applied; in which the laser radiation increases the temperature only in the area where it is applied, on the catalysts, such that the emission plasma reaches a temperature close to 3400 K, capable of achieving the decomposition of CO2, only in that area and not in the entire chamber of the plasma reactor. 12.- Device according to claim 11, wherein the laser uses IR sources,Visible or UV, and emits in pulsed mode with pulse widths of nanoseconds (ns), picoseconds (ps) or femtoseconds (fs), emits in continuous mode (cw)., 13. A device according to claim 11, wherein the laser radiation (4) illuminates the surface of the ceramic substrate in a flat or complex geometry, by using conventional optics or by means of a beam movement system.

14. A device according to claim 11, wherein the laser exclusively illuminates a substrate with one or more catalysts of a ceramic nature, complemented by a plasma unit not coupled to the catalyst irradiated with the laser.

15. A device according to claim 11, wherein the plasma is produced by electrical discharge, microwaves, or other mechanisms, in various geometries based on dielectric barrier discharge (DBD) technology and using plasma power supplies with direct current (DC) or alternating current (AC) input voltage.- Device according to claim 11, wherein the plasma is used with output voltage between 100 V and 10 kV, output frequency between 1 kHz and 100 kHz, output power between 0.5 W and 10 kW, using one or multiple dielectric materials located between the electrodes.

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