Plasma torch and operating method

Abstract

A plasma torch for use in a chemical reactor is described. The plasma torch has a torch chamber having an open end for the outflow of reaction products and a closed end opposite the open end. First and second electrodes are disposed within the torch chamber, the second electrode being between the first electrode and the open end. An input system is provided for the input of one or more gaseous feedstocks into the plasma torch. The plasma torch is adapted to operate at substantially above atmospheric pressure. The plasma torch is also configured such that the flow of the gaseous feedstocks and reaction products through the torch is adapted to prevent or reduce solids deposition on the second electrode. A suitable method of operating the plasma torch in a chemical reactor is also described.

Description

Technical Field

[0001] The present invention relates to a plasma torch and an operating method for the plasma torch. Specifically, it relates to a plasma torch for use in a chemical reactor.

Background Art

[0002] A plasma torch is a device that generates a flow of plasma from a feedstock gas by the action of an electric arc between electrodes. Typically, this is a directed flow of plasma, and the plasma torch is used for various purposes, including cutting, welding, and gasifying waste.

[0003] One particular field of use for plasma torches, or plasma burners, is reactors for pyrolysis. One process that uses such a plasma burner is the Kvaerner process for decomposing hydrocarbons to form carbon black and hydrogen. This is an endothermic reaction that occurs in the plasma burner at approximately 1600 degrees Celsius. The Kvaerner process reaction is as follows.

Number

[0004] Unlike most methods for forming hydrogen from hydrocarbons, carbon dioxide is not a byproduct, so this can be a particularly clean method for forming useful products from hydrocarbons such as methane, which are mainly treated as contaminated waste gases. It is desirable to be able to develop a plasma torch that is particularly suitable for use in reactions such as the Kvaerner reaction.

Summary of the Invention

[0005] In a first aspect, the present invention provides a plasma torch for use in a chemical reactor, the plasma torch comprising: a torch chamber having an open end for the outflow of reaction products and a closed end opposite the open end; a first electrode positioned in the torch chamber; a second electrode positioned in the torch chamber between the first electrode and the open end; and an input system for the input of one or more gaseous feedstocks into the plasma torch, the plasma torch being adapted to operate substantially above atmospheric pressure, and the plasma torch being configured such that the flow of gaseous feedstocks and reaction products through the torch prevents or reduces solid deposition on the second electrode.

[0006] Using this approach, the plasma torch is effective in processing the feed gas without significant deposition occurring within the plasma torch itself. This allows the plasma torch to be used for extended periods without being shut down, thus enabling the reactor to operate continuously for long periods.

[0007] In embodiments, at least the second electrode is substantially cylindrical. This second electrode may have a circular cross-section, but the cross-sectional diameter will vary along the length of the second electrode. In certain embodiments, the second electrode may include a venturi nozzle and a diffuser section at its open end to collimate the outflow of reaction products. This approach keeps the reaction products away from the walls of the plasma chamber, prevents deposition, and accelerates and directs the reaction products so that the plasma torch provides an output jet of the reaction products. As will be discussed below, this can be used very effectively in the overall reactor design.

[0008] The closed end may, in embodiments, be formed by a ceramic cup. A section of the torch chamber having one or more gas inputs from the input system may generally have a circular cross-section. One or more gas inputs may be oriented tangentially to the circular cross-section of the torch chamber. These one or more gas inputs may be located in a ceramic ring element whose inner surface forms part of the wall of the torch chamber. Multiple gas inputs may be located in this ceramic ring element, and the gas inputs are arranged symmetrically around the inner surface of the ceramic ring element.

[0009] Using this approach of providing a gas input, the torch chamber can be shaped to support a helical flow of gas through the torch chamber. Such a helical flow of gas through the torch chamber may include a double helix structure, i.e., a larger diameter helix from the gas inlet(s) to the closed end of the torch chamber and a smaller diameter helix from the closed end to the open end of the torch chamber. This approach has several advantages. Firstly, the reaction between the feed material gas and the plasma spark occurs mainly in the inner helix, and the output products are generated mainly in the inner helix and then rapidly transported through the open end of the plasma torch. Secondly, the electrode is generally at a lower temperature than the reaction temperature because it is adjacent to the feed material gas before the reaction, rather than being superheated by the reaction products from the plasma spark. This improves the electrode life and, therefore, the life of the plasma torch.

[0010] In the embodiment, there may be one or more intermediate electrodes positioned between the first electrode and the second electrode. Such intermediate electrodes may be substantially cylindrical in shape.

[0011] In embodiments, either or both of the first and second electrodes may be porous, and each such porous electrode may be connected to a gas input to allow gas to flow through the electrode. Using this approach, a gas input at a lower temperature can be used to directly cool the electrode, again extending the electrode's lifespan. The passage of such gas through the electrode may have a component either toward or away from the open end of the torch chamber. In this way, the gas can act as a protective curtain for the electrode, and it can cooperate with a helical flow regime for the feed material gas and reaction products passing through the plasma torch.

[0012] As mentioned, such plasma torches can be adapted to operate at internal pressures substantially above atmospheric pressure, but while this approach also has advantages at lower pressures (such as 10 barg or 30 barg), operation at around 50 barg (e.g., within an operating range of 40–60 barg) is practical to achieve and provides high reaction throughput.

[0013] A plasma torch can be adapted such that the gaseous feedstock contains at least one hydrocarbon and the reaction product contains hydrogen. The plasma torch can then operate to decompose the hydrocarbon into its constituent parts, in which case the solid deposit may be a deposit of carbon. In this approach, the gaseous feedstock may further contain hydrogen as a gas input to each porous electrode. Thus, the output from the plasma torch contains hydrogen and carbon, with hydrogen mainly containing the reaction product, along with some gas inputs for cooling the electrodes.

[0014] In embodiments, the plasma torch is adapted to spray into a non-reactive liquid, such as a liquid metal. A diffuser may then be adapted to provide a collimated jet of reaction product effluent into the non-reactive liquid. In embodiments, when the plasma torch is turned off, the non-reactive liquid enters and partially fills the plasma torch chamber. This can be used to clean the plasma torch chamber, regenerate the electrodes (in the case of liquid metal), and provide a soft start for the plasma torch without erosion from the initial spark, as the effect of the initial voltage pulse may be absorbed by the plug (in the case of liquid metal or other conductive material, which is liquid at reaction temperature but solid at ambient temperature) that is heated and discharged at startup.

[0015] In a second aspect, the present invention provides a method for operating a plasma torch in a chemical reactor, the plasma torch comprising a torch chamber having an open end for the outflow of reaction products and a closed end opposite the open end, a first electrode positioned in the torch chamber, a second electrode positioned in the torch chamber between the cathode and the open end, the plasma torch further comprising an input system for inputting a feedstock gas into the plasma torch, the method comprising: flowing one or more feedstock gases into the torch chamber through the input system; consuming one or more feedstock gases in the plasma torch to form one or more reaction products; and operating the flow of feedstock gases and reaction products through the plasma torch to prevent or reduce solid deposition on the second electrode, wherein the pressure in the plasma torch is substantially above atmospheric pressure.

[0016] In such a method, solid deposition can be reduced by accelerating the flow through the second electrode by using a venturi nozzle. In an embodiment, the wall of the torch chamber is substantially circular in cross-section into which the feed material gas is injected, and solid deposition is reduced by injecting the feed material gas into the torch chamber tangentially to the circular cross-section of the torch chamber wall such that the feed material gas employs a helical path through the torch chamber. Such a helical path may comprise a larger diameter helix from the gas input into the torch chamber to the closed end of the chamber and a smaller diameter helix from the closed end of the chamber to the open end of the chamber, thereby maintaining the flow of reaction products away from the wall of the torch chamber. The first and second electrodes may be configured such that the spark gap between them passes mainly through the smaller diameter helix.

[0017] As mentioned, such plasma torches can be adapted to operate at internal pressures substantially above atmospheric pressure, but while this approach also has advantages at lower pressures (such as 10 barg or 30 barg), operation at around 50 barg (e.g., within an operating range of 40–60 barg) is practical to achieve and provides high reaction throughput.

[0018] In this embodiment, the first electrode and the second electrode may be arranged such that a spark between the first electrode and the second electrode erodes any solid deposits on the second electrode.

[0019] In the embodiment, one or both of the first and second electrodes may be porous, and the input gas can flow through and over the surface of each such porous electrode so that solid deposits are prevented on the surface of each such porous electrode. Flowing the input gas through each such porous electrode in this manner may erode the solid deposits by reacting with the deposited solid material. Preferably, the porous electrode or the input gas flowing through each porous electrode has a flow component in either direction toward or away from the open end of the torch chamber. The input gas may be adapted to cool the porous electrode so that the porous electrode or the input gas flowing through each porous electrode can be substantially colder than the feed material gas or reaction products.

[0020] The flow of reaction products emanating from the plasma torch may be directed as a jet into a flow of an unreactive liquid, such as a liquid metal. When the plasma torch is off, the unreactive liquid may enter and partially fill the plasma torch chamber. During operation, such a flow of reaction products may provide heat and momentum to the flow of the unreactive liquid. The unreactive liquid may include a liquid metal, a liquid metal alloy, or a liquid salt. In certain embodiments, if the unreactive liquid is liquid at the reaction temperature and solid at ambient temperature, and the unreactive liquid is also conductive, this has a particular advantage for torch ignition. If a liquid metal alloy is used, this may include lead or bismuth. The feed gas may include methane or another suitable hydrocarbon. The feed gas may also include hydrogen, which is used as the input gas for the porous electrode(s).

[0021] Herein, embodiments of the present invention are described as examples with reference to the attached figures. [Brief explanation of the drawing]

[0022] [Figure 1] A side view of a reactor according to an embodiment of the present invention is shown. [Figure 2]Shows a high-level schematic of the main functional elements of a reactor according to an embodiment of the present invention. [Figure 3] Shows a longitudinal cross-sectional view of a plasma torch from a reactor according to an embodiment of the present invention. [Figure 4] Shows details from the plasma torch of FIG. 3, illustrating additional elements of the anode and features for preventing carbon accumulation. [Figure 5] Shows the flow of reaction gas through the plasma torch of FIG. 3. [Figure 6A] Shows a side view and a cross-sectional view of a ring for the inlet of a feedstock gas for use in the plasma torch of FIG. 3. [Figure 6B] Shows a side view and a cross-sectional view of a ring for the inlet of a feedstock gas for use in the plasma torch of FIG. 3. [Figure 7] Shows a revolver system comprising a set of plasma torches and a feedstock system according to an embodiment of the present invention. [Figure 8] Shows a plasma torch in the process of removal from the revolver system of FIG. 7. [Figure 9A] Shows a gear ring system for the rotation of the revolver system of FIG. 7. [Figure 9B] Shows a gear ring system for the rotation of the revolver system of FIG. 7. [Figure 10] Shows a feedstock system for use in the revolver of FIG. 7. [Figure 11] Illustrates an exemplary reaction process for a reactor system according to an embodiment of the present invention. [Figure 12] Illustrates a liquid metal pyrolysis reactor system driven by the plasma torch system of FIGS. 3 - 11 and including a housing for the plasma torch system. [Figure 13A] Illustrates the liquid metal circulation system of the reactor of FIG. 12 driven by a plasma torch. [Figure 13B] Illustrates the liquid metal circulation system of the reactor of FIG. 12 driven by a plasma torch. [Figure 14A] Figures 13A and 13B provide different cross-sectional views of the liquid metal circulation system. [Figure 14B] Figures 13A and 13B provide different cross-sectional views of the liquid metal circulation system. [Figure 15] Figure 12 illustrates the liquid metal pyrolysis reactor in more detail. [Figure 16] Along with the carbon output, Figure 15 illustrates the supply system to the liquid metal pyrolysis reactor. [Figure 17] Figure 16 shows the supply system in the vortex chamber of the liquid metal pyrolysis reactor. [Figure 18] Figure 15 shows a vertical cross-section passing through a portion of the liquid metal pyrolysis reactor. [Figure 19] The modified reaction flow for synthesis gas production is shown. [Figure 20A] A different figure of a second embodiment of the plasma torch for use in embodiments of the present invention is shown. [Figure 20B] A different figure of a second embodiment of the plasma torch for use in embodiments of the present invention is shown. [Figure 21A] A different figure of a third embodiment of the plasma torch for use in embodiments of the present invention is shown. [Figure 21B] A different figure of a third embodiment of the plasma torch for use in embodiments of the present invention is shown. [Figure 22] This is a system diagram of a reactor system according to a further embodiment of the present invention. [Modes for carrying out the invention]

[0023] General and specific embodiments of the present invention are described below with reference to the drawings.

[0024] Figure 1 provides a perspective view of a reactor according to an embodiment of the present invention. Reactor 1 is formed as a pressure vessel 2 having an electrical input for supplying power to a plasma torch (not shown here, but Figure 12 shows how this is integrated into the system) and a gas input 4 for introducing gaseous feed material into the system. Each of these inputs is directed to a revolver assembly (not shown here, see Figures 7-9 and 12 for further details) which is adapted to fit into an assembly aperture 5, and the revolver assembly houses a set of plasma torches and also provides gaseous feed material to each plasma torch. The reactor shown herein has multiple stages, with the plasma torch acting as a first reactor stage, and a liquid metal reactor acting as a further reactor stage that consumes the heat generated by the plasma torch. The reaction product includes a heating gas, which is hydrogen in the main embodiment discussed below, and a heat exchanger effectively acts as a pre-reactor stage, using the heating gas to bring the feed material gas to the correct temperature for the reaction.

[0025] The reactor system is schematically shown in Figure 2. A gaseous input 11, such as a hydrocarbon like methane, and additional hydrogen for cooling (which may be recycled from the output products) are introduced into a plasma torch 12, which consumes the input feed gas to provide a first set of output products such as carbon and hydrogen. These first output products pass through a liquid metal system 14 as input 13 at a high temperature, then, in embodiments, provide thermal decomposition of further feed gas. Depending on the design, final output products 15, such as carbon and hydrogen output as a gas, which may be extracted through the liquid metal or from the gaseous output, are provided from the liquid metal reactor 14 after the separation process, and these final output products include the first output products from the plasma torch 12 and may be complemented by further output products generated from thermal decomposition in the liquid metal reactor 14. The thermal decomposition reaction is endothermic, but there is extra heat available to use, as there is enough heat to keep the gaseous final output products at a temperature significantly higher than the desired temperature for storage. Here, this heated gas output is used by a heat exchanger 16 that controls the temperature of the feed gas for different stages of the reactor process. As will be further discussed below, embodiments of the present invention may not require all the features shown in the arrangement of Figure 2 to operate, and the arrangement of Figure 2 is a synergistic combination of a series of processes for particularly effectively producing carbon and hydrogen from hydrocarbons such as methane. As will be further discussed below, such processes may also be adapted to produce other output products such as synthesis gas.

[0026] Embodiments of the plasma torch are shown in detail in Figures 3 to 5. A longitudinal cross-sectional view of the plasma torch 30 is provided in Figure 3. The plasma torch 30 is generally cylindrical, and in the arrangement used in embodiments of the present invention, it extends into a liquid metal circulation system 40 (to be discussed further below), where it is injected directly into the liquid metal. The plasma torch has a central chamber 300 containing a cathode 31 and an anode 32. These can be any conductive material suitable for the conditions in the central chamber 300, and carbon (graphite) can be used, or any suitable metal or alloy that is homogeneous or has suitable inserts, for example, copper with a hafnium insert is a possible option. Here, the cathode 31 is located toward the end of the plasma torch 30 away from the liquid metal reactor 39, and a ceramic cup-shaped end section 38 terminates the plasma torch. In alternative torch designs, electrodes may be positioned in opposite directions, or an AC plasma torch may be used, meaning that the transmission is only about the electrodes, not the anode and cathode. The anode is generally cylindrical but has a shaped inner surface 34 with a nozzle 35 and a diffusion section 36, which will be described in more detail below. A protective electrode 33 may be positioned between the cathode 31 and the anode 32, and those skilled in the art will again understand that the electrode structure may be modified to achieve a desired electric field pattern within the plasma torch chamber, may include zero, one or more intermediate electrodes, and multiple protective electrodes may be cascaded to help stabilize the spark for effective ignition or to prevent anode wear. A gas input 37 is provided for introducing a gaseous feedstock into the reactor, and in the arrangement shown in Figure 3, methane is introduced into the gas input 37 located at the protective electrode 33. In different embodiments of the invention, different gas input positions are provided for different feedstock gases, as will be described in more detail below.The following discussion primarily concerns methane, but it should be understood that other hydrocarbons can also be commonly used. For example, propane, although transported in liquid form, readily evaporates for reactions in plasma torch reactors, and therefore would be another particularly suitable option for processing.

[0027] Figure 4 illustrates one phenomenon in the use of the plasma torch 30 shown in Figure 3 to decompose methane. In this reaction, methane decomposes into hydrogen gas and carbon at high temperatures through the action of a plasma torch spark, which can have a temperature of 6000 degrees Celsius, resulting in instantaneous decomposition. A practical problem is that this can lead to carbon deposits 41 that clog the torch, which significantly affects the efficiency of the process and can result in significant downtime for maintenance. It would be desirable to prevent such carbon accumulation and for both reaction products to exit the plasma torch 30. One feature to achieve this is to protect the anode with a gas that inhibits accumulation. This can be achieved by making the anode 32 porous, and the anode gas output 42 delivers a gas (in this case, hydrogen) through the anode to provide a protective curtain along the inside of the anode, inhibiting carbon accumulation. The gas is delivered at an angle to the anode such that it has a velocity component toward the plasma torch output to achieve this protective curtain; alternatively, the velocity component can be delivered away from the plasma torch output, so that it still provides a protective curtain to the electrode. In addition to providing a protective curtain, there can also be active erosion of deposited carbon by hydrogen, as hydrogen can react with carbon in a reverse reaction back to methane, thus further eroding the deposited carbon. Hydrogen also plays a role in cooling the anode, preventing it from degrading. In addition to using a porous anode in this way, the cathode can also be made porous and cooled in a similar manner.

[0028] Further strategies are used to prevent carbon accumulation. Anode shaping may also be arranged so that there are likely deposit points for carbon on the anode within the spark gap region with the operating torch, and the sparking action can then further erode any carbon accumulation.

[0029] Another feature that prevents carbon buildup is illustrated in Figure 5, illustrating the passage of gas through the plasma torch structure. Here, methane enters the plasma torch tangentially through a gas input 37 at the protective electrode, and this input methane generally moves toward the cathode along a helical path. The gas input 37 here is provided through a ceramic ring 51, which is shown in more detail in Figures 6a and 6b. The ceramic ring 51 has a gallery 52 for the circulation of the input gas around the ring, allowing the input gas to pass through several channels 53 (four in the illustrated design) that deliver the input gas tangentially into the chamber, establishing both a helical path of output gas adjacent to the chamber wall, and also vortices within the plasma torch chamber. This can be optimized by taking into account the gas type, flow conditions, pressure, and temperature to achieve the desired flow pattern. The wall structure (particularly the wall roughness and geometric shape) facilitates the outer helix of the gas maintaining its momentum and separating from the faster-rotating inner helix, while the torch's geometric shape pushes the gas into an inner return helix with a faster velocity and a tighter inner circle. The gas adopts this tighter helix as it moves between the cathode and anode, and maintains this during heating as it decomposes into carbon and hydrogen in the spark gap between the cathode and anode. Plasma formation is rapid, typically taking less than 1 microsecond. For gases, suitable tuning allows for adjustment (by pressure, temperature, and density) to minimize energy exchange between helices, similar to a tornado. This configuration already gives the output gas (in this case, hydrogen) a significant velocity towards the output of the plasma torch, preventing carbon condensation and deposition as carbon forms in the center of the plasma torch chamber rather than on the walls. Plasma contains ions and electrons with balanced energy levels near thermal equilibrium, and molecules are primarily broken down into atoms. Under the operating temperature and pressure conditions of a plasma torch, the stable state of carbon exists as a gas, reducing the possibility of carbon deposition. Plasma torches are generally designed to promote the reaction in the center of the chamber and inhibit it at the walls, so that reaction products are preferentially driven from the plasma torch to the liquid metal reactor.The outer helix cools and insulates the wall while preventing atomic carbon in the inner helix from condensing on the wall. Hydrogen from the reaction passes through nozzle 35, which, according to the Venturi effect, results in an increase in velocity and a decrease in pressure. The gas is then ejected from the plasma torch 30 through diffuser 36 at high temperature (and kinetic energy), and the plasma is ejected from the torch at supersonic speed. By the cumulative effect of these features, carbon is generally carried into the plasma torch output without significant accumulation of deposits on the anode wall. The role of diffuser 36 is to match the pressure of the plasma torch output to that of the next reactor step, as will be described in more detail below. In embodiments described in detail herein, as referred to herein, the next reactor step is a liquid metal reactor, and the liquid metal herein may also be used to interact directly with the torch, as will be discussed further below.

[0030] Alternative plasma torch designs for use in embodiments of the present invention are shown in Figures 20a and 20b (for a second torch embodiment) and Figures 21a and 21b (for a third torch embodiment). Figures 20a and 20b show a plasma torch in which the gas input line 200 is aligned with the torch chamber, but the cathode 2031 and anode 2032 are separated by a spacer 201, where the cathode 2031 forms a cup end and a smaller diameter passage region 202 is formed through the anode, which opens into a larger diameter passage region 203 for plasma torch output. Figures 21a and 21b show an alternative embodiment having a vortex flow plate 2151 that provides gas inflow into the chamber at a closed end adjacent to a tubular cathode 2131 (here made of molybdenum). The anode 2132 is stepped, as before, with a smaller diameter passage region 212 and a larger diameter passage region 213, but in this case, these regions are shorter relative to the plasma chamber, and the larger diameter passage region 213 terminates in a diffuser 214 with a linearly increasing diameter.

[0031] This configuration in the torch described above allows for operation at very high temperatures (above 6000 degrees Celsius at the reaction point) and high pressures in the torch, with extremely high throughput of gaseous feedstock. With 200 kW of power input to the plasma torch, and an operating temperature of 6000 degrees Celsius in the torch chamber at the reaction point and a pressure of 50 bar, approximately 72 kg / hour of methane can be processed using this design. The voltage across the electrodes is typically 150V–600V, typically around 250V, and the operating current is 100A–500A, typically around 200A. The feedstock gas can be preheated by using a heat exchanger, utilizing the heat released in the pyrolysis reaction (see further consideration below), although the hydrogen used to cool the anode is supplied at a lower temperature.

[0032] High-pressure operation of the plasma torch is common to the embodiments of the invention described herein, and the reaction system is typically contained within a pressure vessel, as shown in Figure 1. However, effective reactions can be achieved at various pressure regimes, and while the systems described herein are particularly suited to operation at 50 barg (50 bar above atmospheric pressure), they distinguish themselves from conventional approaches to the use of plasma torches related to pyrolysis by high-pressure operation. The use of the system at lower but still high pressures (20 barg, 10 barg, or 1 barg) allows for more efficient operation than at temperatures where it operates at atmospheric pressure. Operation at lower temperatures and with lower power torches is also possible, as will be further discussed below (this will be further considered below with respect to Figure 22).

[0033] Figures 7 to 10 illustrate an embodiment of the present invention that illustrates a system for attaching a plasma torch and supplying gaseous raw materials and electricity to the plasma torch.

[0034] One potential problem with this type of reactor design is that if a plasma torch needs to be maintained, the reactor can lose significant efficiency due to the long cycle time required to shut down the plasma torch. This is because the torch needs to be reduced to a much lower temperature and pressure for maintenance, and then returned to that temperature and pressure to operate again. In embodiments of the present invention, the approach taken is to use multiple torches for each "torch position" in the reactor, one of the plasma torches being in the active position and ready to operate, while the other plasma torches are in other positions that can be removed or prepared to operate without affecting the torch that is actually operating. This approach can be effectively combined with an efficient system for supplying power and gaseous feedstock to the plasma torches.

[0035] Figure 7 shows one embodiment of this multiple torch approach, in which three torches 71, 72, and 73 are mounted on a carousel or revolver 70. The revolver 70 can rotate around its longitudinal axis, but after rotation, it is locked in one of three positions, either an active position or an active bay, where one of the three torches operates within the reactor. A feedthrough system 74 is provided along the axis of the revolver 70, and this system is configured to supply gaseous feed material and power to the plasma torch in the active position. The other two plasma torches are not in the active position and can be prepared for use or extraction; for example, one of the two positions may be a “ready” position (or loading bay) where the torch has reached its operating temperature, and the other of the two positions may be a “cool-down” position (or cooling bay) where the active torch has previously cooled and is ready for removal for maintenance.

[0036] Figure 8 shows the plasma torch fitted into the torch position in the revolver. The three torch positions are arranged symmetrically around the axis of the revolver, and the plasma torch is provided with appropriate pressure sealing so that it can maintain the pressure in the plasma torch chamber when it is rotated into the active bay, and slides from the side away from the reactor until it locks into place.

[0037] Figures 9A and 9B show a gear system 91 in which the revolver bay can rotate between three available positions, and any suitable gear system can be used. A locking mechanism is provided so that the bay can be locked only in a specified position, and in the case of three bays, this includes three possible locking positions. Figure 9B shows two ways in which this can be done. A pin 93 on the revolver cap can pass through the revolver core and be used to lock the revolver in place. Alternatively, one of the gears, for example, the gear 92 of the stepping motor connection, can be locked in place by motor control (each of the gear shafts can be locked in this way if desired).

[0038] Figure 10 shows a feedthrough system for use with the revolvers shown in Figures 7–9. A feedthrough system 74 is provided for each revolver, providing electrical and gaseous inputs to the torch in the active bay, and inputs may also be provided to other bays (e.g., cooling gas to the cooling bay) if necessary, but generally the feedthrough system is configured to have inputs only to the active bay for use with the torch in the working position. In contrast to the torch, the feedthrough system employs a fixed configuration to the bay so that the correct input is provided to the active bay regardless of which torch is positioned in the active bay at any given time. Using this approach, specific input locations can be specified for specific input gases. In some cases, this may generally be independent of the reactions in the plasma torch (e.g., cooler hydrogen may be input to cool the anode in several different reactions), but in other cases, specific gaseous inputs may be provided to enter the plasma torch at specific locations 75 for specific reactions, and multiple gas inputs 37 in the plasma torch (see Figure 3) may alternate with these supply outputs 75. The feedthrough system can thus be coded (e.g., color-coded) for specific feed material gases and specific reactions. In Figure 10, the gaseous input is shown, but the electrical connections are not. However, the ceramic insulator 76 is shown to isolate the connections on the torch, particularly the electrical connections. With respect to the torch, this arrangement needs to be provided with an effective pressure seal that allows for the maintenance of a pressure of 50 bar within the plasma torch chamber during use. Different approaches can be taken to construct a suitable feed material system, but the approach shown here uses a series of aligned disks, in this case metal disks 77 separated by ceramic insulating disks 78.

[0039] Although the feedstock system is described above in relation only to the input, it can also be used for the output. For example, if there is recirculation (for example, hydrogen which is produced as an output but is also used as a cooling gas), the recirculation system can use both the input and output through the feedstock system.

[0040] It should be noted here that different torches may, in fact, be used for different reactions. For example, one torch may be designed with a feedstock input position optimized for methane, and another torch may be designed with a different input position optimized for a different feedstock gas. These different input positions may be aligned with different positions on the feedstock system in such a way that only the correct combination of input gas and torch can be used. It may also be possible to reconfigure the feedstock system so that the same feedstock gas can be supplied to different positions for different torches (or even different reactions), which can be achieved by adding valves to the feedstock system with a set of valve positions pre-configured for a particular arrangement.

[0041] Before describing the other elements of the reactor, the overall reaction flow is described with respect to Figure 11. This reaction flow is specific to the decomposition and thermal decomposition of methane, but in this specification, it is used more generally to illustrate the different reaction processes that occur in different parts of a combined reactor. For example, other hydrocarbons such as propane can be used as feed hydrocarbons instead of methane not only in plasma torch reactors but also in liquid metal reactors.

[0042] Two inputs to the system, namely electricity 1101 and hydrocarbons 1102 (in this case, methane), are shown. Two outputs, namely hydrogen 1103 (however, for other reactions, other output gases may be provided similarly or instead, and it should be noted that some of the generated hydrogen is recycled for use in the reaction process) and carbon black 1104, are shown.

[0043] Both inputs are supplied to the plasma torch 1105, and hydrogen is supplied as an input in addition to power and hydrocarbon feedstock. In the configuration shown, a low-temperature hydrogen input 1111 (shown here in the range of 200-400 degrees Celsius) is supplied to the plasma torch 1105, for example, to cool the anode with high-temperature hydrocarbons 1112 (shown here at approximately 700 degrees Celsius) used as reaction feedstock, and also to maintain the temperature and pressure of the reaction chamber and to facilitate the flow of material through the plasma torch. Once the plasma torch consumes electrical energy and generates a high-temperature output, this is partially consumed by a pyrolysis reaction in a second reactor 1122, from which the heated output gas can be used in a heat exchanger 1121 to circulate the hydrocarbon feedstock so that it rises from low-temperature hydrocarbons 1113 at approximately 200 degrees Celsius to high-temperature hydrocarbons 1112 at the plasma torch reaction temperature of approximately 700 degrees Celsius, and the heat exchanger 1121 can also supply hydrogen to the plasma torch at a lower temperature. Therefore, this heat exchanger 1121 effectively acts as a first reactor process, absorbing the heat from the termination process and using it to bring the gas required for the reaction stage to the correct temperature.

[0044] The plasma torch 1105 itself acts as a second reactor 1122, providing high-temperature hydrogen and (primarily) gasified carbon as output 1114. The plasma torch 1105, through its reaction products, operates in the next reactor stage, which is the liquid metal pyrolysis reactor 1123. The plasma torch 1105 provides heat for this reaction, heating the metal (in this case, lead) to the reaction temperature, and also provides rotation to the lead, allowing the carbon to be extracted at the center of the reactor. Higher-temperature hydrocarbons 1115 are supplied from the heat exchanger 1121 as feedstock for the liquid metal pyrolysis reactor 1123. The hydrogen output 1116, provided at a very high temperature (approximately 1200 degrees Celsius) from the heat dissipation reaction in the pyrolysis reactor, is returned to the heat exchanger 1121 and partially recirculated to the plasma torch 1105, while being supplied (at a lower temperature) primarily as hydrogen gas output 1104.

[0045] The liquid metal pyrolysis reactor is shown in detail in Figures 12–18. Figure 12 illustrates the main elements of the reactor assembly. The torch mounting section 121 is oriented into the liquid metal racetrack 122 that supplies the main reactor volume 123. There is also a gas input 124 to the main reactor volume 123, which includes a vortex chamber 125. The liquid (molten) metal is delivered into the vortex chamber 125 to give rotation to the liquid metal column, allowing the liquid metal to initiate the pyrolysis reaction in the input gas and acting as a centrifuge, separating the reaction products toward the center of the rotating column. Carbon is then extractable from the base of the reactor at a carbon output 126. Hydrogen rises from the liquid metal and is released from the top of the reactor through a hydrogen output 127. The reaction is carried out at high temperature and high pressure (typically 800–1000 degrees Celsius and 50 bar).

[0046] This function can be usefully combined with the function of a plasma torch, even when the liquid metal system itself is not a reactor, in which case it acts only as a separator to separate reaction products from the plasma torch, which is powered by the energy of the plasma torch output. However, this leaves a significantly excess of heat, and it has been found that using the liquid metal system itself as a reactor for further endothermic pyrolysis of hydrocarbons leads to a particularly effective reactor system.

[0047] Figures 13A and 13B show the plasma torch mounting section and liquid metal racetrack from different angles, and Figures 14A and 14B show different cross-sectional views of these elements. The liquid metal, as it cools, exits the reaction chamber, the reaction products are separated, and then it passes through the elbow joint 128 to the liquid metal racetrack 122 toward the plasma torch mounting section 121, and the plasma torch output is injected into the liquid metal. This heats the liquid metal to a temperature sufficient to initiate a thermal decomposition reaction with hydrocarbons such as methane, and also carries the reaction products of the plasma torch reaction to the liquid metal reactor so that they can be collected from the system (the methane passing from the plasma torch jet into the liquid metal can also be thermally decomposed at this point). The heated metal passes along the rest of the liquid metal racetrack and enters the liquid metal reactor chamber from the bottom. The components of the racetrack structure must, as a result, withstand the high temperatures from the heated liquid metal, and they also need to be adapted to expansion due to the significant temperature difference between the temperature during the reaction process and the temperature outside the reaction process. The joint can be protected, for example, by the use of a molybdenum sleeve 141, as shown in Figure 14B.

[0048] The plasma torch is designed to effectively inject into the liquid metal racetrack 122, and in particular, the diffuser of the plasma torch is designed to match the pressure outside the torch. This has the advantage of supporting a linear flow rather than turbulence within the liquid metal racetrack. The liquid metal can be formed into a vortex or spiral that acts to stabilize the plasma jet. The reaction products from the plasma torch, hydrogen and carbon in the shown embodiment, are carried into the liquid metal for subsequent separation and output from the liquid metal reactor in the liquid metal reactor, as described below.

[0049] Liquid metal systems can also be useful for purging the output of a plasma torch reactor from impurities. For example, ethylene may be produced as a byproduct, but can then be decomposed again in a liquid metal system.

[0050] Liquid metal from a liquid metal system can have other functions. For example, the diffuser of a plasma torch may extend far enough into the liquid metal racetrack so that the liquid metal acts to clean the diffuser and prevent carbon buildup therein, and in embodiments, the diffuser section may be partially porous to support the flow of liquid metal. If desired, the liquid metal from the racetrack can even be driven to overflow the plasma torch, rapidly quench the reaction, and stop its operation. Thus, the liquid metal can be used to immerse and thus clean porous anode (and cathode, if used) structures.

[0051] This affects the system's operation during shutdown and startup. When a plasma torch is stopped, some backfilling of the plasma torch structure from the liquid metal racetrack can be expected, and the liquid metal may enter the torch chamber and solidify as the torch cools (depending on the choice of metal). If porous electrodes are used, the electrodes, or at least the electrodes closest to the torch percha, may be filled with liquid metal. This can be used to the advantage of the torch's effective operation and to extend its working life. The electrodes can be directly replenished with solidified metal, which can compensate for erosion during use. Restarting a plasma torch is usually achieved using high-voltage pulses, which will typically have a significant aging effect on the electrodes and torch structure in general. If liquid metal has entered the torch chamber, especially if it has formed a solid metal plug, the effect of starting the torch is significantly softened. Such solid metal plugs typically form a link between the electrodes of a plasma torch, and therefore, high-voltage pulses typically result in a high current (perhaps 200A) through the plug, heating and melting it very rapidly. The combination of plug melting and the supply of feed gas to the torch results in the rapid removal of the metal plug, while also providing a soft start to the plasma torch, reducing the aging effect of the plasma torch's power cycle. The result is a more effective self-ignition process, aided by the liquid metal system. To make the release of the plug faster, this can be stimulated by injecting gas behind the plug or by creating a vacuum in front of the plug to pressurize the plug forward into the liquid metal system. Mechanical systems for engaging with and removing the plug are also possible.

[0052] Lead, or a mixture containing lead, may be used as the liquid metal in a liquid metal system. Lead is a preferred choice because it is liquid at the reaction temperature without having a high vapor pressure and causes fewer toxicity problems than most other preferred metals. Gallium, as well as bismuth, is another possible option. One alloy used in embodiments of the system is WR58, which contains bismuth and lead, available from William Rowland Ltd. The term “liquid metal” is used throughout this specification, but in embodiments, the circulating liquid may not be a metal itself, provided that it is liquid at the reactor temperature and supports the separation of reaction products (and, if acting as a reactor, supports further thermal decomposition), but does not itself undergo further chemical reactions with the feed material gas or thermal decomposition reaction products. Several salts also have suitable properties. As mentioned above, if a cooling plug is used for torch self-ignition, the circulating liquid needs to be solid and somewhat conductive when the reactor is cold.

[0053] As mentioned above, the liquid metal system here is designed to function not only as a separator but also as a reactor. Figure 15 provides a diagram of the vortex chamber 125 that forms the reaction chamber for the liquid metal pyrolysis reactor. The heated liquid metal is passed through this chamber from below along with the input gas, and the circulation within the vortex chamber 125 leads to the separation to the center of the circulating liquid metal column, along with the reaction products separated by centrifugal action, where carbon and hydrogen are first collected in a hat structure 151 at the top of the reactor. This can be used to collect clean hydrogen, which is the only gas at this point and can simply be released through a float valve. A liquid salt structure can be provided in this structure for a mixture of lead and carbon to permeate, where carbon is separated from lead, and the process is completed by gravity, with the lighter carbon floating above both the heavier lead and salt. This allows the carbon to be separated by dropping it through a chute in the central region of the chamber. The base plate 152 below the vortex chamber 125 has through holes for gaseous input. The cooling metal exits through holes in the side of the vortex chamber 125, goes down through the base plate 152, and there circulates on the liquid metal racetrack shown in Figures 13 and 14.

[0054] Further details of the vortex chamber 125 are shown in Figures 16 to 18.

[0055] Figure 16 shows the lower part of the liquid metal reactor vessel below the vortex chamber 125 where the reaction takes place. Hot metal heated from the plasma torch enters from below through the metal inlet 161, along with the reaction gas entering through the gas inlet 162. Carbon is output through the bottom of the reactor at the carbon output 163. Hydrogen is circulated downward through the base plate 152 of the vortex chamber 125 for subsequent circulation and collection on the vortex chamber.

[0056] Figure 17 shows the region above the base plate 152 of the vortex chamber 125. The liquid metal is introduced tangentially into the liquid metal column through the elbow 171, which provides rotation to the liquid metal column so that it acts as a centrifuge. Also shown in Figure 17 is the infiltration inlet 172 for further feed material gas, in this case methane for pyrolysis. The infiltration inlet 172 is located here immediately before the liquid metal from the elbow 171, thereby allowing the further feed material gas to infiltrate directly into the liquid metal flow for pyrolysis. This process can be further developed by using a suitable catalyst; for example, nickel balls (not shown here) can be included in the vortex chamber 125, which extend the flow path of the injected methane, promote the reaction, and clean up impurity hydrogen. Nickel balls are an attractive option because they float on lead (when used as liquid metal) but sink on salt, thus effectively trapping them in the separation layer. The connection through the base plate 152 is shown in more detail in the cross-sectional view of Figure 18.

[0057] As described above, a heat exchanger system is provided that allows the heat generated in the reaction to be used to provide an input gas at the correct temperature for use in the reaction. Hydrogen output from the liquid metal reactor, which is at a high temperature (1200 degrees Celsius), is used to heat the methane feedstock for supply to both the plasma torch and the liquid metal pyrolysis reactor. A portion of this hydrogen output is cooled to a much lower temperature (e.g., 200-400 degrees Celsius) and used to cool the anode and cathode of the plasma torch, as described above.

[0058] Although the reactor embodiments described herein are adapted for the thermal decomposition of methane, this reactor structure can be used for many reactions. As mentioned in the consideration of the feedstock system, for example, various input gases can be used in different reactions at selected gas input locations to achieve proper gas circulation throughout the plasma torch. Similarly, different inputs can be supplied to a liquid metal reactor, not just methane, to achieve different reactions.

[0059] The reactor process described in the above embodiment is intended for the production of hydrogen and carbon from methane, but the reactor structure used here can be adapted to other reaction processes. As shown in Figure 19, methane or another hydrocarbon is decomposed into hydrogen and carbon either directly in a plasma torch or through subsequent thermal decomposition in a liquid metal reactor (191), and after separation (192) occurs in the liquid metal separator, synthesis gas (syngas or synthesis gas is mainly a mixture of hydrogen and carbon monoxide) can be produced by adding carbon dioxide to the carbon stream as a further input gas (193). The carbon dioxide is reduced by carbon to form carbon monoxide, which can be collected with hydrogen above the vortex chamber and extracted as synthesis gas. Using this approach, the carbon monoxide is released outside the vortex chamber and permeates at the top of the vessel for collection. At that time, both hydrogen (from the hat above the vortex chamber) and synthesis gas (from the top of the entire liquid metal reactor structure) may be present.

[0060] In the approaches generally described above, heat from the plasma torch is used by endothermic reactions, primarily methane pyrolysis, to establish an efficient combined reactor. While this is an effective use of the heat provided by the plasma torch, if there is an alternative method of using this heat, the liquid metal system does not need to be used as a reactor. In other embodiments, for example, the liquid metal system may be used essentially for the separation of hydrogen and carbon produced by the plasma torch reactor, in which case the supply of methane to the liquid metal system is not required.

[0061] Most of the heat from the plasma torch reactor is used by the endothermic methane pyrolysis reaction, but a significant proportion of the heat is removed from the reactor by a hydrogen output provided at high temperatures (typically 1200 degrees Celsius). In the configuration shown here, this is used to bring the feed gases, i.e., methane for the plasma torch and methane for the liquid metal reactor, to the reaction temperature in a conventional heat exchanger. As described above, further output from the heat exchanger is preferably a low-temperature hydrogen stream for cooling the electrodes. However, if there is an effective alternative use for this output heat, this heat exchanger does not need to be used, and other approaches may be employed to raise the gas to a suitable reaction temperature, with a hydrogen source at ambient temperature or another side reaction temperature being used.

[0062] Figure 22 is a system diagram of a reactor system according to a further embodiment of the present invention. In this design, the operating temperature is lower, the liquid metal system transports the product from the torch for separation rather than providing an additional reactor step, and a heat exchanger step is not used. This reactor system is designed for lower temperature operation (obviously, local temperatures at the plasma spark will be significantly higher, but here, about a typical temperature of 250°C with an operating range of 200–300°C throughout the reactor), but is also designed for high-pressure operation (typically 50 barg as the reactor pressure, with an operating range of 40–60 barg). In this configuration, the hydrocarbon feed 2202, preferably methane, is supplied at ambient temperature and preheated to 80°C before being supplied to the plasma torch 2205. In this embodiment, a single plasma torch is used (a revolver is not present). The system is designed for a throughput of 18 kg / hour with the entire system operating around 50 barg. The plasma torch 2205 operates at 50 kW (maximum 800 VDC, 300 amps). The reaction products of hydrogen and carbon black are ejected into a liquid metal handling system (which may also be called a quench reactor, which is equivalent to the “plasma reactor” in the arrangement of Figure 11), in which case the liquid metal system uses a WR58 alloy heated to at least 80°C, and the liquid metal system 2214 is supplied from the metal supply tank 2214a. The reaction products are extracted from the liquid metal handling system 2214 by an extraction system 2230, which here comprises first and second cyclones 2231, 2232 and a pulse jet filter 2233 (with a switchable alternative pulse jet filter). Each of these systems deposits the carbon black as a solid while the gas, mainly containing hydrogen, proceeds to the next stage. In the configuration shown, the first cyclone 2231 receives the flow from the reactor at 18 kg / hour, 48 barg, and 200°C. Since the solid deposited by the first cyclone 2231 is carbon black containing several metal alloys, a separator is required at this point.The second cyclone 2232 accepts input at 17.66 kg / hour, 47 barg, and 190°C, and outputs gas at 4.96 kg / hour, 46 barg, and 185°C, releasing more carbon black. This output is received by a pulse jet filter 2233, which releases more carbon black, and outputs hydrogen gas that is cooled to ambient temperature in a cooler 2234. The carbon black is deposited in an intermediate bulk container 2235, and the indicated arrangement optimizes the deposition into the second and third bulk containers so that the majority of the generated carbon black does not require separation from the liquid metal.

[0063] Further embodiments can be produced at higher operating temperatures, up to high-temperature operation (which may be 1200°C) of the arrangement in Figure 11. Such designs may utilize features of either or both of the arrangements in Figures 11 and 22 as needed. For example, an intermediate design may have a heat exchanger similar to that shown in Figure 11, while using the type of separated arrangement shown in Figure 22.

[0064] As those skilled in the art will understand, other embodiments of the plasma torch and reactor technology and reaction processes described herein may be provided within the scope of the claims, without being limited to specific features described in the embodiments but not required by the claims.

Claims

1. A plasma torch for use in a chemical reactor, wherein the plasma torch is A torch chamber having an open end for the outflow of reaction products and a closed end on the opposite side of the open end, A first electrode is placed in the torch chamber, A second electrode positioned in the torch chamber between the first electrode and the open end, the second electrode being substantially cylindrical and having a cross-sectional diameter that varies along the length of the second electrode, and comprising a nozzle and a diffuser section at the open end for collimating the outflow of reaction products, An input system for inputting one or more gaseous feedstocks into the plasma torch, wherein a section of the torch chamber having one or more gas inputs from the input system has a circular cross-section, the one or more gas inputs are directed tangentially to the circular cross-section of the torch chamber, and the torch chamber is shaped to establish a helical flow of gas through the torch chamber; A plasma torch is adapted to operate substantially above atmospheric pressure to decompose a gaseous feed material, and the plasma torch is configured such that a helical flow of gas through the torch prevents or reduces solid deposition on the second electrode.

2. The plasma torch according to claim 1, wherein the nozzle is a venturi nozzle.

3. The plasma torch according to claim 1, wherein the closed end is formed by a ceramic cup.

4. The plasma torch according to claim 1, wherein the one or more gas inputs are located on a ring element whose inner surface forms part of the wall of the torch chamber.

5. The plasma torch according to claim 4, wherein the ring element has a plurality of gas inputs, and the gas inputs are arranged symmetrically around the inner surface of the ring element.

6. The plasma torch according to claim 1, further comprising one or more intermediate electrodes positioned between the first electrode and the second electrode.

7. The plasma torch according to claim 6, wherein the intermediate electrode or each intermediate electrode is substantially cylindrical.

8. The plasma torch according to claim 1, wherein either or both of the first and second electrodes are porous, and each such porous electrode is connected to a gas input to allow a gas to flow through the electrode.

9. The plasma torch according to claim 1, wherein the plasma torch is adapted to operate at an internal pressure greater than 10 barg, preferably greater than 30 barg, and more preferably in the range of 40 to 60 barg.

10. The plasma torch according to claim 1, wherein the plasma torch is adapted such that the gaseous feed material contains at least one hydrocarbon and the reaction product contains hydrogen, and the solid deposit is a carbon deposit.

11. The plasma torch according to claim 10, wherein either or both of the first and second electrodes are porous, and each such porous electrode is connected to a gas input to allow a gas to flow through the electrode, and the gaseous supply further comprises hydrogen as the gas input to each porous electrode.

12. A method for operating a plasma torch in a chemical reactor, wherein the plasma torch comprises a torch chamber having an open end for the outflow of reaction products and a closed end opposite the open end; a first electrode positioned in the torch chamber; a second electrode positioned in the torch chamber between the first electrode and the open end, the second electrode being substantially cylindrical and having a cross-sectional diameter that varies along the length of the second electrode, and comprising a nozzle and a diffuser section at the open end for collimating the outflow of reaction products; the plasma torch further comprises an input system for inputting a feedstock gas into the plasma torch, and a section of the torch chamber having one or more gas inputs from the input system having a circular cross-section, the one or more gas inputs being oriented tangentially to the circular cross-section of the torch chamber, and the torch chamber being shaped to establish a helical flow of gas through the torch chamber, and the method is as follows: By flowing one or more supply material gases into the torch chamber through the input system, a helical flow of gas passing through the torch chamber is established. Decomposing one or more supply material gases in the plasma torch in order to form one or more reaction products, A method comprising operating a spiral flow of feed material gas and reaction products through the plasma torch and out of the diffuser section through the nozzle, such that the pressure in the plasma torch is substantially above atmospheric pressure, in order to prevent or reduce solid deposition on the second electrode.

13. The method according to claim 12, wherein the nozzle is a venturi nozzle, and solid deposition is reduced by accelerating the flow through the second electrode.

14. The method according to claim 12, wherein the helical flow comprises a larger diameter helix from the input of gas into the torch chamber to the closed end of the torch chamber and a smaller diameter helix from the closed end of the torch chamber to the open end of the torch chamber, thereby maintaining the flow of reaction products away from the walls of the torch chamber.

15. The method according to claim 14, wherein the first electrode and the second electrode are configured to fit such that the spark gap between them passes mainly through a helix of a smaller diameter.

16. The method according to claim 12, wherein the first electrode and the second electrode are arranged such that a spark between the first electrode and the second electrode erodes any solid deposits on the second electrode.

17. The method according to claim 12, wherein one or both of the first electrode and the second electrode are porous, and solid deposition is prevented on the surface of each such porous electrode by flowing an input gas through and on the surface of each such porous electrode.

18. The method according to claim 17, wherein passing an input gas through each of such porous electrodes erodes the solid deposit by reacting with the deposited solid material.

19. The method according to claim 17, wherein the porous electrode or the input gas flowing through each porous electrode has a flow component that is either toward the open end of the torch chamber or away from the open end.

20. The method according to claim 17, wherein the porous electrode or the input gas flowing through each porous electrode is substantially colder than the feed material gas or reaction product, and the input gas is adapted to cool the porous electrode.

21. The method according to claim 12, wherein the internal pressure in the plasma torch during operation is greater than 10 barg, preferably greater than 30 barg, and more preferably in the range of 40 to 60 barg.

22. The method according to claim 12, wherein the flow of reaction products from the plasma torch is directed as a jet into a flow of non-reactive liquid.

23. The method according to claim 22, wherein when the plasma torch is turned off, the non-reactive liquid enters and partially fills the plasma torch chamber.

24. The method according to claim 22, wherein the flow of the reaction product provides heat and momentum to the flow of the non-reactive liquid.

25. The method according to claim 22, wherein the non-reactive liquid includes a liquid metal, a liquid metal alloy, or a liquid salt.

26. The method according to claim 22, wherein the nonreactive liquid is a liquid at the reaction temperature and a solid at ambient temperature.

27. The method of claim 12, wherein the supply raw material gas comprises hydrocarbons, optionally methane.

28. The method according to claim 27, wherein one or both of the first electrode and the second electrode are porous, and solid deposition is prevented on the surface of each such porous electrode by flowing an input gas through and on the surface of each such porous electrode, and the supply raw material gas further comprises hydrogen, the hydrogen being used as the input gas for the porous electrode(s).

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