Dielectric barrier discharge plasma reactor and method for carrying out gas-phase chemical reactions

Abstract

The dielectric barrier discharge plasma reactor (1) for activating gas-phase chemical reactions comprises at least one tubular pipe (11) made of a dielectric material, an inner electrode (13) and an outer electrode (12). The inner electrode is confined to the entrance of the active area (10a) of the reactor, so that a voltage pulse applied between both electrodes creates a propagating discharge in the active area. The reactor creates a volume contact between the gas flow (F) containing the reactants and the plasma created by the discharge, allowing an efficient transfer of activation energy between the plasma and the reactants.

Description

Detailed Description of the Invention

[0001] The present invention relates to a dielectric barrier discharge plasma reactor.

[0002] 〔Background Art〕 It is known to use a plasma reactor to activate gas-phase chemical reactions. The role of the plasma is to provide sufficient activation energy to the reactants so that the reaction occurs more rapidly. When the reactor is designed to produce a reaction involving a continuous supply of reactants, the plasma enables a higher conversion rate to be obtained for these reactants during the same duration that the reactants are present in the reactor.

[0003] Many configurations of plasma reactors have already been proposed. Some of the points to consider for these configurations are as follows: Obtaining a high value of reactant conversion rate, Operating the reactor stably during continuous operation, and Designing a smaller reactor that processes the same amount of reactants supplied to the reactor.

[0004] The proposed configurations vary in particular depending on the geometric shape of the electrodes used to generate the plasma and the properties of the plasma thus generated. Specifically, for generating plasma in a chemical reactor, configurations such as dielectric barrier discharge, glow discharge, corona discharge, high-frequency discharge, microwave discharge, grinding arc discharge, or rotating arc discharge have been proposed. For example, European Patent Application Publication 1 541 821 A1 describes a reactor having a dielectric barrier discharge and a wire-cylindrical electrode configuration. In this reactor of European Patent Application Publication 1 541 821 A1, the electrode, in its wire shape, is parallel to the flow direction of the gas flow containing the reactants and is in contact with this gas flow. A positive voltage pulse is applied to the wire electrode relative to an external cylindrical electrode to generate plasma. However, due to the accumulation of charge appearing on the surface of the dielectric material in contact with the gas, the plasma is formed only over a limited length between the wire electrode and the dielectric barrier and is measured parallel to the wire electrode. Therefore, the contact time between the reactants and the plasma is short, and the conversion rate of the reactants is limited accordingly.

[0005] The same limitations apply to reactor configurations where the plasma is generated in a layered shape, and the gas flow containing the reactants crosses the plasma layer substantially perpendicular to it.

[0006] [Technical issues] Based on this situation, one object of the present invention is to propose a new type of plasma chemical reactor in which the above-mentioned drawbacks of conventional reactors are reduced or eliminated.

[0007] In particular, the present invention aims to provide a plasma chemical reactor that has stable operation and enables a higher conversion rate for the chemical reactions carried out therein.

[0008] [Summary of the Invention] To achieve this or other objectives, a first aspect of the present invention proposes a plasma reactor for activating gas-phase chemical reactions: The invention comprises at least one tubular pipe made of a dielectric material, having a central axis and arranged to guide a gas flow containing one or more reactants from the inlet end to the outlet end of the tubular pipe, Each tubular pipe, (i) An internal electrode disposed within the tubular pipe with a separation radius distance between the internal electrode and the tubular pipe, (ii) An external electrode is provided, which is positioned on the outside of the tubular pipe and arranged to generate a substantially uniform potential within the longitudinal section of the outer surface of the tubular pipe, and whose inner volume relative to the tubular pipe superimposed on the longitudinal section in an orthogonal projection on the central axis is called the active region of the reactor.

[0009] The reactor further includes a power supply connected between the internal electrode and the external electrode of each tubular pipe.

[0010] Therefore, the plasma reactor of the present invention is of the dielectric barrier discharge type.

[0011] According to a first feature of the reactor of the present invention, the reactor is designed by (iii), and the internal electrode is positioned within the tubular pipe near the boundary of the active region, called the upstream boundary of the active region, and is oriented toward one of the inlet end and the outlet end. Furthermore, the internal electrode has a spike shape oriented toward the other of the inlet end and the outlet end, and extends parallel to the central axis toward the latter end, without exceeding 10% of the length of the active region, according to measurements formed parallel to the central axis from the upstream boundary of the active region to the tip of the internal electrode. By means of such a configuration of the spike cylinder electrode, the discharge generated in the gas flow has a propagating discharge configuration that starts from the tip of the internal electrode and extends longitudinally within the active region. Such a propagating discharge consists of an ionization head composed of several filaments called a streamer and an ionization channel commonly called a leader. Thus, the length of the plasma zone can be increased, and the gas flow can be brought into contact with the plasma inside the entire three-dimensional volume. Thus, activation energy is transferred to the reactants over the entire duration that the gas flow passes through the plasma in this three-dimensional volume. Due to the fact that the present invention provides such a large amount of plasma, this duration allows for longer and higher conversion rates to be obtained at the same flow rate of gas flow. The 10% upper limit on the protrusion of the internal electrode into the active region ensures that each discharge generated by the voltage pulse applied between the internal and external electrodes has a structure that propagates longitudinally within the tubular pipe without significant impact on the radial component of the internal electrode. Preferably, the protrusion of the internal electrode from the upstream boundary of the active region into the region may be less than 5% of the length of the active region.

[0012] In the context of the present invention, the term "spike shape" for an internal electrode refers to a protruding shape having a radius of curvature of the convex surface of the internal electrode, which is less than 100 μm (micrometers), preferably greater than 0.1 μm and less than 50 μm.

[0013] In this specification, the inlet and outlet ends of the tubular pipe are also designed in relation to the direction of gas flow within the tubular pipe. Furthermore, the upstream boundary of the active region is also designed in relation to the position of the internal electrodes and, consequently, in relation to the longitudinal extension of the propagating discharge within the tubular pipe. However, in another embodiment of the present invention, the upstream boundary of the active region may be alternately oriented toward the inlet end or toward the outlet end of the tubular pipe, meaning that the active regions alternate near one or the other. In other words, the direction of extension of the discharge propagating from the spike-like internal electrodes is parallel to the central axis within the tubular pipe and can be in the same direction as or opposite to the direction of gas flow within the tubular pipe.

[0014] According to a second feature of the reactor of the present invention, the reactor is designed as described in (iv), and the inner diameter of the tubular pipes in the active region of the reactor is 0.05 mm to 10 mm. This distance constitutes a compromise between the capacities of each tubular pipe to guide the gas flow with sufficient flow rate and limited head loss, and to obtain a plasma that substantially occupies the entire internal cross-sectional area of ​​the tubular pipe.

[0015] Finally, according to a third feature of the reactor of the present invention, the power supply is adapted to deliver alternating positive and negative voltage pulses into the active region of the reactor during the reactor's operation, along with the maximum absolute value of the voltage of each pulse adapted to generate a discharge in the gas flow, in accordance with the convention of voltage signs corresponding to the potential of the internal electrodes minus the potential of the external electrodes. The alternation between positive and negative pulses can neutralize any charge that may accumulate on the inner surface of each tubular pipe made of dielectric material. Thus, the plasma reactor can have stable continuous operation with significant extension of each propagating discharge within the active region of the reactor, parallel to the central axis. Subsequently, the plasma in each tubular pipe can occupy a significant length section of the active region, and at the same time, it occupies all or almost all of the cross-sectional area of ​​the tubular pipe within this length section. In other words, the reactor of the present invention enables stable volumetric or three-dimensional contact between the plasma and the gas flow containing the reactants. Thus, improved conversion efficiency values ​​can be obtained.

[0016] The potential generated by the external electrode, which is uniform in the longitudinal section of the outer surface of the tubular pipe, is understood to mean a potential exhibiting spatial variation within the longitudinal section of the outer surface of the tubular pipe, which is less than 10% of the absolute maximum instantaneous voltage of each pulse. This upper limit of spatial variation in potential is met, in particular, before the start of each pulse. This upper limit is compatible with various geometric configurations of the external electrode, as well as various conductive materials that are possible components of this external electrode. In particular, it is compatible with external electrodes made of carbon.

[0017] Preferably, the power supply is adapted so that the positive or negative electrical pulses delivered by the power supply can be adjusted during the use of the plasma reactor to neutralize the charge remaining on the dielectric material after the previous electrical pulse, or to reverse the sign of the charge remaining on the dielectric material from one pulse to the next. Thus, electrical shielding present on the inner surface of the tubular pipe, which may limit the plasma volume in the longitudinal direction, can be avoided.

[0018] In some cases, the reactor may further include a catalyst placed inside a tubular pipe. Therefore, if the voltage of the positive pulse is sufficient for the propagating discharge to reach the catalyst, the reactor can be of the IPC type for "in-plasma catalyst".

[0019] In a preferred embodiment of the present invention, at least one of the following additional features may be reproduced individually or in combination: Each electrical pulse delivered by the power supply during reactor operation may have a peak voltage value between 1 kV (kilovolts) and 100 kV in absolute value, preferably between 10 kV and 40 kV: The power supply may be adapted to generate voltage pulses at frequencies between 1 Hz and 100 kHz during reactor operation: The length of the internal electrode inside the active region should be less than 2 mm (millimeters), measured parallel to the central axis between the upstream boundary of the active region and the tip of the internal electrode. The internal electrodes may consist of sections of metal wire, such as tungsten or steel wire, having a wire diameter between 50 μm (micrometers) and 400 μm: The length of the active region, measured parallel to the central axis, may be between 1 mm and 500 mm, preferably between 50 mm and 200 mm. The thickness of the tubular pipe in the active region can be 50 μm to 500 μm, measured perpendicular to the central axis. Such a thickness for the dielectric material of the tubular pipe prevents each voltage pulse from being delivered by a power source with a very high peak voltage value, so that discharge occurs in the gas flow.

[0020] The external electrode may have one of the following forms in the active region: a wire of conductive material wrapped around a tubular pipe, a sheath of conductive material surrounding the tubular pipe while in contact with the outer surface of the tubular pipe, one or more planar metal surfaces in contact with the outer surface of the tubular pipe, and The dielectric material of the tubular pipe within the active region may be quartz, glass, or ceramic.

[0021] In some embodiments of the present invention that accept a larger total gas flow rate, the reactor may comprise a plurality of tubular pipes arranged in parallel to guide each gas flow simultaneously, each tubular pipe containing the reactants. Each tubular pipe is then provided with each internal electrode and each external electrode, or provided with each portion of the external electrode, which is shared by the plurality of tubular pipes, and each tubular pipe satisfies the corresponding internal and external electrodes or the features of (i) to (iv) above. Furthermore, a power supply is connected between all the internal electrodes on one side and all the external electrodes on the other side or the shared external electrode. In this way, the number of tubular pipes in the reactor can be 3 to 400.

[0022] A second aspect of the present invention proposes a method for carrying out a gas-phase chemical reaction, which is carried out using a reactor according to the first aspect of the present invention in order to activate a chemical reaction. This reaction may in particular be one of the following: Decomposition of carbon dioxide into carbon monoxide and oxygen molecules: Reaction to produce methane and water from carbon dioxide and hydrogen: A reaction for producing hydrogen molecules and solid carbon, for which purpose the gas stream comprises at least methane, which is pure or one or more added gases: and, A reaction for producing hydrogen molecules, for which purpose the gas stream comprises at least ammonia, which is pure or one or more added gases.

[0023] Advantageously, during the use of the plasma reactor, the peak voltage value of each pulse is adjusted such that this pulse neutralizes the charge that may remain on the inner surface of each tubular pipe after the previous pulse, or, with respect to the previous pulse, reverses the sign of the charge remaining on this inner surface of the tubular pipe after the pulse.

[0024] [Brief Description of the Drawings] The features and advantages of the present invention will become more apparent from the following detailed description of some non-limiting and exemplary embodiments, with reference to the accompanying drawings.

[0025] FIG. 1 is a longitudinal cross-sectional view of a basic plasma reactor module according to the present invention.

[0026] FIG. 2 is a perspective view showing a plurality of basic modules according to FIG. 1 assembled within a plasma reactor according to the present invention.

[0027] [Detailed Description of the Invention] For the sake of clarity, the dimensions of the elements represented in these figures do not correspond to actual dimensions nor to actual dimensional ratios. Furthermore, some of these elements are represented only symbolically, and the same reference signs shown in different figures indicate the same element or elements having the same function.

[0028] In Figure 1, the basic plasma reactor module according to the present invention is collectively denoted by reference numeral 10. It comprises a tubular pipe 11, which is, for example, a glass or alumina (Al2O3) tube, extending between an inlet end 11e and an outlet end 11s. The inlet end 11e leads to a gas flow intake chamber 2, and the outlet end 11s leads to a gas flow collection and discharge chamber 3. The connections between the inlet end 11e and the outlet end 11s to the respective chambers 2 and 3 are sealed. Thus, a gas flow F containing chemical reactants can be continuously introduced into the pipe 11. The pipe 11 may be cylindrical with a circular cross-section, having an inner diameter Dint and an outer diameter Dext equal to 0.6 mm and 1.0 mm, respectively, and a pipe length which may be equal to, for example, 150 mm. However, other cross-sectional shapes, such as a square cross-section (shown in Figure 2), may be used for the pipe 11.

[0029] The external electrodes 12 are arranged around the pipe 11, are external to it, and have a shape adapted to generate a uniform or substantially uniform potential over the length La of the active region. For example, the external electrodes 12 can be realized by metal deposits on the outer surface of the pipe 11 to form a cylindrical electrode of length La. Electrical contacts can be mounted on the external electrodes 12 by any known technique. The section of the pipe 11 located within the external electrodes 12 is referred to as the active region of the reactor in the general part of this specification and is indicated by reference numeral 10a. For example, the length La of the active region 10a can be equal to 130 mm, measured between the upstream boundary 10am and the downstream boundary 10av of the active region 10a, where the upstream and downstream are oriented with respect to the direction of the gas flow F within the pipe 11. In other words, the upstream boundary 10am and the downstream boundary 10av of the active region 10a coincide with the upstream and downstream edges of the external electrodes 12.

[0030] The internal electrodes 13 are fixedly arranged at the end 11e of the pipe 11, for example, in the axial direction. The internal electrodes 13 are superimposed on the central axis AA of the pipe 11 and penetrate the pipe 11 from the inlet end 11e to substantially the level of the upstream boundary 10am of the active region 10a. For example, in the downstream direction, the internal electrodes 13 are 1 mm above the upstream boundary 10am of the active region 10a. The internal electrodes 13 have a spike shape, and their orientation is also superimposed on the central axis AA and directed downstream. However, precise superimposition of the internal electrodes 13 with respect to the central axis AA is not essential, and a limited offset between the two does not significantly impair the operation of the plasma reactor. For example, the internal electrodes 13 can be made of a rigid metal wire, for example, tungsten (W) with a diameter of 150 μm. Thus, the gas flow F can flow between the internal electrodes 13 and the inner surface of the pipe 11.

[0031] The rigid metal wire constituting the internal electrode 13 may be stretched by locally heating it at the point where it is cut to form its spike shape, resulting in a spike shape having a radius of curvature of less than 100 μm, for example, about 20 μm.

[0032] Power supply 4 is connected between electrodes 12 and 13. Preferably, the external electrode 13 is connected to the ground terminal of source 4 such that the voltage U supplied by source 4 is equal to the potential of the internal electrode 13. Source 4 is selected to supply alternating positive and negative voltage pulses at a frequency of, for example, 50 Hz. The peak value of the voltage U of each pulse is adjusted to generate plasma between the internal electrode 13 in the active region 10a and the inner surface of pipe 11. Due to the electrode configuration described above, each pulse generates a discharge that propagates within pipe 11, the length of which depends on the peak voltage value of the pulse. Thus, the length of the propagating discharge can range from a few millimeters to almost the entire length La of the active region 10a. The peak voltage value of each pulse can also be adjusted according to the gas composition of flow F, which is equal in absolute value to 1 kV to 100 kV, for example, 25 kV. In this way, a volume contact is created between the plasma generated by the propagating discharge within pipe 11 and the gas flow F. Such a volume contact allows for the efficient transfer of activation energy from the plasma to the reactants contained in the gas flow F.

[0033] The peak voltage value of each electrical pulse is adjusted to favorably stabilize the steady state of the discharge, in other words, to obtain continuous and stable operation of the plasma reactor. Such stabilization corresponds to the neutralization by each pulse of the charge generated by the previous pulse on the inner surface of pipe 11 within the active region 10a. Preferably, the peak voltage value of each pulse can be adjusted to deposit a charge on this inner surface having the opposite sign to the charge left by the previous pulse. Such inversion of the charge present on the inner surface of pipe 11 by each pulse promotes the generation of a propagating discharge.

[0034] Figure 2 shows a portion of a plasma reactor 1, which consists of a parallel connection of multiple basic modules 10, each following Figure 1. A complete reactor 1 can have any number of basic modules 10, preferably 3 to 400 (including both ends), but Figure 2 shows only 8 for clarity. The modules 10 may be arranged, for example, in a 20 × 20 matrix arrangement in a common cross-sectional plane for all modules 10. The gas flow intake chamber 2 and the gas flow collection and discharge chamber 3 may be shared by all modules 10, so that each tubular pipe 11 of all modules 10 connects chamber 2 to chamber 3 in parallel, guiding separate gas flows F from one chamber to the other. Furthermore, the power supply 4 may also be shared by all modules 10, and the electrical connections are arranged in parallel so that each electrode 12 and 13 of all modules 10 connects to the power supply 4 in the same connection direction. According to one possible configuration of reactor 1, each module 10 can be placed within a dedicated housing of a support structure 5, the support structure 5 being electrically conductive, thereby ensuring electrical contact with the external electrodes 12 of all modules 10. The support structure 5 is advantageously connected to the ground terminal of the power supply 4. In an alternative embodiment of reactor 1, the support structure 5 can directly constitute the external electrodes 12 of all modules 10.

[0035] The plasma reactor 1 can be used for many chemical reactions. The reactants are contained in a gas stream supplied to the reactor 1 and introduced into the intake chamber 2. Such chemical reactions, even if some of the reaction products are solid, are commonly referred to as gas-phase reactions. Some non-limiting examples of gas-phase chemical reactions that can be advantageously carried out in the reactor 1 are, in particular: CO2 → CO + 1 / 2O2 CO2 + 4H2 → CH4 + 2H2O, commonly known as the Sabatier reaction. CH4 → 2H2 + C NH3 → (3-x) / 2H2 + NH x Here, x is a stoichiometric coefficient between 0 and 3.

[0036] The gas stream supplied to reactor 1 may consist of the reactants themselves, or these reactants diluted in a carrier gas that is inert to the chemical reaction under consideration. Optionally, other chemical components may be added to the gas stream to reduce the activation barrier of the reaction or to shift the equilibrium to suit the product.

[0037] Reactor 1 can be used in combination with catalyst 14 (shown in Figure 1), the latter selected in known ways according to the chemical reaction under consideration. For example, non-limitingly, catalyst 14 may be nickel (Ni) powder or an alloy based on at least one noble metal element such as platinum (Pt). Then, when reactor 1 is oriented so that the pipes 11 are substantially horizontal, catalyst 14 is placed inside each pipe 11, preferably in the corresponding active region 10a. In this case, reactor 1 is an IPC type for "in-plasma catalyst". Alternatively, catalyst may be placed on the inner surface of each pipe 11, or on a segmented substrate such as microbeads, powder having substrate function, or foam made from alumina (Al2O3) or zirconia (ZrO2), etc., to suit the flow of each gas flow F.

[0038] It is understood that the present invention can be reproduced by modifying secondary aspects of the embodiments described in detail above, while retaining at least some of the cited advantages. For example, the described shapes of the external electrodes 12 of each module 10 and all cited materials can be adapted or modified in particular according to the chemical reactions carried out in reactor 1. In addition, the detailed description of the present invention is provided only as an example of an embodiment in which the direction of gas flow in each tubular pipe is the same as the direction of propagation of the discharge originating from the spike-shaped internal electrodes. In fact, the internal electrodes 13 are closer to the inlet end 11e than to the outlet end 11s. However, it should be recalled that the direction of propagation of the discharge from the spike-shaped internal electrodes can also be opposite to the direction of gas flow in the tubular pipe. In other words, the internal electrodes 13 can alternatively be located at or near the outlet end 11s of the tubular pipe 11. Finally, all cited figures are provided for illustrative purposes only and can be modified depending on the application considered. [Brief explanation of the drawing]

[0039] [Figure 1] This is a longitudinal cross-sectional view of a basic plasma reactor module according to the present invention. [Figure 2] This is a perspective view showing a plurality of basic modules according to Figure 1, assembled within a plasma reactor according to the present invention.

Claims

1. A dielectric barrier discharge plasma reactor (1) for activating a gas-phase chemical reaction, The device comprises at least one tubular pipe (11) made of a dielectric material, having a central axis (A-A) and arranged to guide a gas stream (F) containing one or more reactants from the inlet end (11e) to the outlet end (11s) of the tubular pipe, Each tubular pipe (11) (i) An internal electrode (13) is placed inside the tubular pipe (11) with a separation radius distance between the internal electrode and the tubular pipe, (ii) An external electrode (12) is provided, which is located on the outside of the tubular pipe (11) and is arranged to generate a uniform potential within the longitudinal section of the outer surface of the tubular pipe, and whose inner volume relative to the tubular pipe superimposed on the longitudinal section in an orthogonal projection on the central axis (A-A) is called the active region (10a) of the reactor (1), The reactor (1) is Each tubular pipe (11) is further provided with a power supply (4) connected between the internal electrode (13) and the external electrode (12), Each tubular pipe (11) (iii) The internal electrode (13) is positioned within the tubular pipe (11) near the boundary of the active region (10a) called the upstream boundary (10am) of the active region, and is oriented toward one of the inlet end (11e) and the outlet end (11s), and the internal electrode has a spike shape oriented toward the other of the inlet end and the outlet end, and extends parallel to the central axis (A-A) toward the other of the inlet end and the outlet end, and the length measured parallel to the central axis from the upstream boundary of the active region to the tip of the internal electrode does not exceed 10% of the length (La) of the active region. (iv) The inner diameter (Dint) of the tubular pipe (11) in the active region (10a) is 0.05 mm to 10 mm. The reactor (1) is characterized in that the power supply (4) is adapted to deliver alternating positive and negative voltage pulses into the active region (10a) during the operation of the reactor (1), in accordance with the convention of voltage signs corresponding to the potential of the internal electrode (13) after subtracting the potential of the external electrode (12), along with the maximum absolute value for the voltage (U) of each pulse adapted to generate an electrical discharge in the gas flow (F).

2. The reactor (1) according to claim 1, further comprising a catalyst (14) disposed inside the tubular pipe (11).

3. The reactor (1) according to claim 1, wherein the power supply (4) is adapted to generate the voltage pulse (U) at a frequency of 1 Hz to 100 kHz during the operation of the reactor.

4. The reactor (1) according to claim 1, wherein the length of the internal electrode (13) inside the active region (10a) is less than 2 mm, measured parallel to the central axis (A-A) between the upstream boundary (10am) of the active region and the tip of the internal electrode.

5. The reactor (1) according to claim 1, wherein the internal electrode (13) consists of a section of metal wire having a wire diameter of 50 μm to 400 μm.

6. The reactor (1) according to claim 5, wherein the internal electrode consists of a section of tungsten or steel wire.

7. The length (L) of the active region (10a) ａ The reactor (1) according to claim 1, wherein the distance between the central axis (A-A) is measured parallel to the central axis (A-A) and is between 1 mm and 500 mm.

8. The length (L) of the active region (10a) ａ The reactor (1) according to claim 7, wherein the distance between the central axis (A-A) is measured parallel to the central axis (A-A) and is 50 mm to 200 mm.

9. The reactor (1) according to claim 1, wherein the thickness of the tubular pipe (11) in the active region (10a) is 50 μm to 500 μm when measured perpendicular to the central axis (A-A).

10. The reactor (1) according to claim 1, wherein the external electrode (12) has one shape in the active region (10a) of a wire of a conductive material wound around the tubular pipe (11), a sheath of a conductive material surrounding the tubular pipe in the portion that is in contact with the outer surface of the tubular pipe, and one or more planar metal surfaces in the portion that is in contact with the outer surface of the tubular pipe.

11. It is equipped with multiple tubular pipes (11) arranged in parallel to guide each gas flow (F) simultaneously, Each contains the aforementioned reactants, Each tubular pipe is provided together with each internal electrode (13) and each external electrode (12), or together with each portion of the external electrode that is shared by a plurality of the tubular pipes. Each tubular pipe having the corresponding internal electrode and external electrode or external electrode portion satisfies the characteristics of (i) to (iv), The power supply (4) is connected between all of the internal electrodes on one side and all of the external electrodes on the other side or the shared external electrode. The reactor (1) according to claim 1, wherein the number of tubular pipes (11) in the reactor (1) is 3 to 400.

12. A method for carrying out a gas-phase chemical reaction, wherein the reaction is activated by using the reactor (1) described in claim 1.

13. The aforementioned chemical reaction is Decomposition of carbon dioxide into carbon monoxide and oxygen molecules. The reaction that produces methane and water from carbon dioxide and hydrogen. A reaction that produces hydrogen molecules and solid carbon, wherein the gas stream contains at least methane. A reaction that produces hydrogen molecules, wherein the gas stream contains at least ammonia. The method according to claim 12, selected from among the following.

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