Patent Application
20250025852
The present application claims the benefits of Chinese patent applications 202111567211.X, 202111565360.2, 202111567220.9, 202111567216.2, 202111567218.1, 202111565366.X, 202111565369.3, 202111567199.2, and 202111567219.6 filed on Dec. 20, 2021, Dec. 20, 2021, Dec. 20, 2021, Dec. 20, 2021, Dec. 20, 2021, Dec. 20, 2021, Dec. 20, 2021, Dec. 20, 2021, and Dec. 20, 2021, the contents of which are incorporated herein by reference.
The present invention relates to the field of energy chemical industry, in particular to a gliding arc plasma reactor, and a method for converting methane by means of plasma.
The plasma methane conversion technology is researched from the last 80 years in China, and gradually forms a patent technology from 2000.
CN100999432A discloses a method for preparing C2 hydrocarbons by ionic liquid catalytic plasma methane conversion, and the patent rights were terminated in 2015.
CN101734620A discloses a method for producing hydrogen by methane-rich gas plasma, and the patent rights were terminated in 2014.
The southwest chemical research and design institute has published a series of plasma methane cracking patent technologies (CN 210367505U, CN109294284A, CN106478332A and CN 101921163A), and the technology is mainly developed aiming at the technology of preparing carbon black or acetylene and hydrogen by converting methane through plasma, and particularly emphasizes on the design and optimization of the technology.
The technology for preparing acetylene by plasma cracking coal (CN 203582763U, CN102068953A, CN101734620A, CN101550057A, CN101734995A and CN 1613839A) is jointly developed by Tsinghua University, Taiyuan University of Technology and Xinjiang Tianye Co., Ltd., coal is mainly used as a raw material, natural gas is used for preparing acetylene and hydrogen in an auxiliary way, and the working gas is hydrogen.
Zhejiang University is mainly developed aiming at a plasma online decoking method (CN 104056828A and CN 104056829A), and CO2 or H2 can be introduced to remove carbon on the surface of an electrode. A rotating arc plasma is also developed to crack methane to prepare acetylene (CN 103333044A, CN 101844744A), working gas rotates to enter a discharge gap, and simultaneously, millisecond-level cracking occurs by adopting magnetic field driving from the outside.
At present, foreign related researches show that hydrocarbon products formed by converting methane by means of plasma mainly belong to two types, wherein one type mainly comprises alkane such as ethane and the like, and the other type mainly comprises acetylene.
Researchers have found that the product distribution can be adjusted by varying the feed gas flow or by incorporating inert gases. The technology has been industrialized abroad, and comprises four processes: the HUELS method, the AVCO method, the Du Pont method, and the Romania method.
Through literature comparison, the utilization of electric arc to generate high-temperature cracked natural gas to generate acetylene has low electric energy utilization rate, 13900 kWh is consumed for producing 1 ton of acetylene, and the cost is more than 50% of the total cost, so that the purpose of saving energy and reducing consumption is achieved by changing the structure of a reactor, and the method is one of the key points for innovation in foreign patent literature.
On the basis of the technology, a series of ‘warm’ plasma technology and ‘cold’ plasma technology are gradually developed in the follow-up process, energy consumption is reduced by changing an energy generation form, and a catalyst is added for coupling, so that methane is directionally converted into a target product. This process is currently still under investigation.
Thanyachotpaiboon et al (Conversion of methane to high hydrocarbons in AC nonequilibrium plasmas [J]. AIChE Journal, 1998, 44(10): 2252-7.) examined the conversion of methane using DBD discharge at room temperature and examined the effect of adding He and C2H6 on the conversion of methane discharge. When only CH4 is used as a reactant, as the discharge voltage increases (6→11 kV), the CH4 conversion rate increases and the product selectivity does not change much: the products are mainly C2H6 and C3H8; the conversion of CH4, obtained at a flow rate of CH4 of 20mL/min and a discharge voltage of 11 kV, is about 23%, and the selectivities of the products C2H6, C3H8, C4H10 and C2H4 were 40%, 15%, 5% and 2%, respectively.
RUEANGJITT N et al (Non-oxidative reforming of methane in a mini-gliding arc discharge reactor: Effects of feed methane concentration, feed flow rate, electrode gap distance, residence time, and catalyst distance [J]. Plasma Chem Plasma Process, 2011, 31(4): 517-534.) use a gliding blade arc to convert methane, with acetylene as the main product, 40%-50% methane conversion and 20% C2H2 selectivity at a power of 110-190 W.
However, there are currently no existing technical reports on the direct conversion of methane to olefins by means of plasma.
The present invention aims to overcome the defect of low conversion efficiency of directionally converting methane into olefin in the prior art.
In order to achieve the above object, the first aspect of the present application provides a gliding arc plasma reactor comprising a reactor chamber and a gliding arc plasma generator disposed in the reactor chamber;
In the second aspect the present invention provides a method for converting methane by means of plasma, the method being carried out in a gliding arc plasma reactor as described in the first aspect, the method comprising:
Compared with the prior art, the scheme provided by the present invention at least has the following advantages:
Additional features and advantages of the present invention will be set forth in the detailed description which follows.
The endpoints of the ranges and any values disclosed herein are not limited to the precise) range or value, and these ranges or values should be understood to encompass values close to these ranges or values. For numerical ranges, each range between its endpoints and individual point values, and each individual point value can be combined with each other to give one or more new numerical ranges, and such numerical ranges should be construed as specifically disclosed herein.
The embodiment of the present invention will be described in detail with reference to
As previously described, the first aspect of the present application provides a gliding arc plasma reactor comprising a reactor chamber and a gliding arc plasma generator disposed in the reactor chamber;
According to a particularly preferred embodiment, the reactor comprises a reactor inlet 1, a gliding arc plasma generator and a product outlet 5;
According to the present invention, the discharge arc forming point of the electrode is on the curved surface, so that more discharge areas of an arc channel can be formed, and the conversion capability of reactants is stronger.
Preferably, the arc surface structure of the arc surface electrode 3 is a semi-closed arc surface, the central angle corresponding to the arc surface is α, wherein 270°>α>30°; more preferably, the central angle α corresponding to the semi-closed arc surface is at least one selected from 180°, 120°, 90°, 72°, 60°.
According to a preferred embodiment, the arc surface structure of the arc surface electrode 3 is a fully-closed arc surface. The inventor finds that when a fully-closed arc surface structure is used as the arc surface structure of the arc surface electrode 3, the conversion efficiency of the reactant is higher, and the heat dissipation is facilitated.
Preferably, the proportional relationship between the length d2 of the discharge area and the height d3 of the reactor chamber satisfies: 1:1.2-1.8.
According to a preferred embodiment, the electrode gliding arc generator is the gliding arc plasma generator; and the center of the base of the gliding arc plasma generator is provided with the gas nozzle which is communicated with a gas inlet pipeline of the reactor inlet.
Preferably, the central angle corresponding to the arc surface structure of the arc surface electrode 3 is α, wherein 360°≥α>10°.
Preferably, the gliding arc plasma generator comprises two arc surface electrodes 3 or six arc surface electrodes 3 which are symmetrically distributed.
Preferably, on each arc surface electrode 3, the proportional relation between the distance between two adjacent gas nozzles 2 and the inner diameter r2 of gas nozzle satisfies the following conditions: 1:0.5-1.5.
Preferably, a proportional relationship between the inner diameter r2 of the gas nozzle 2 and the minimum width r3 of the discharge area satisfies: 1:2-8.
According to a particularly preferred embodiment, the reactor of the present invention comprises a reactor inlet, an electrode gliding arc generator, a lower reaction zone and a product outlet;
Preferably, in the present invention, the symmetrical distribution is symmetrical distribution based on a central vertical axis of the base, and the mounting position of the electrode does not affect discharge.
In the present invention, the shape and material of the base are not particularly limited, and may be a circular shape or various other shapes that can achieve the aforementioned object of the present invention, and may be an insulating material or various other materials that can achieve the aforementioned object of the present invention.
Preferably, the gas nozzle 2 is arranged at the center of the base 6 of the gliding arc plasma generator, and the gas nozzle 2 is communicated with a gas inlet pipeline of the reactor inlet 1.
Preferably, the gas nozzle 2 is arranged in the relative direction of each two arc surface electrodes 3 in the symmetrical position, and the gas nozzle 2 is communicated with a gas inlet pipeline of the reactor inlet 1.
More preferably, at least a portion of the outer surface of the fully-closed arc surface structure is coated with a coating.
Preferably, the coating comprises at least two laminated plating layers of single-layer atomic layer deposition metal oxide thin films, the plating layers are made of semiconductor materials, the number of layers of the plating layer is at least two, and the coating materials for forming any two adjacent plating layers are different.
Preferably, the number of layers of the plating layer is at least three.
According to a preferable embodiment, the number of layers of the plating layer is three, and the coating materials forming the three plating layers are different; the dielectric constant of the coating material forming the outermost plating layer is 10-22 C2/(N·M2) higher than that of the coating materials of the other plating layers.
Preferably, the coating material is an organic substance containing a metal element.
Preferably, the semiconductor material is a metal oxide; more preferably, the semiconductor material is selected from Al2O3, ZrO2, SnO2, ZnO, HfO2, TiO2, La2O3, Ta2O5, Y2O3.
Preferably, the outer surface of the fully-closed arc surface structure is coated by an atomic layer deposition method, and the coating step preferably comprises the following steps: in an atomic layer deposition apparatus,
Preferably, in the step (1), the temperature of the metal source tank is 140-160° C., the temperature of the reaction chamber is 50-400° C., and the temperatures of the transportation pipeline and the ALD valve are 180-200° C.
Preferably, in step (1), the reaction chamber and the transport line are evacuated to a pressure of 10-200 Pa.
Preferably, in the step (1), the flow rate of the carrier gas for coating is 10-200 sccm.
Preferably, in step (1), the opening time of the ALD valve is 50-2000 ms.
Preferably, in the step (1), an inert gas pulse is introduced to clean the reaction chamber; preferably, the washing time is 1-200 s.
According to a preferred embodiment, the outer surface of the fully-closed arc surface structure is coated by an atomic layer deposition method, and the coating step preferably comprises the following steps: in an atomic layer deposition apparatus,
Preferably, the fully-closed arc surface is at least one selected from a tubular shape and a rod shape.
According to another preferred embodiment, the electrode gliding arc generator is the tubular electrode gliding arc generator; and the gas nozzles are arranged in the relative directions of every two tubular electrodes at the symmetrical positions and the gas nozzles are communicated with an inlet pipe of the reactor inlet.
Preferably, the material forming the gas nozzle is selected from at least one of a conductive material and an insulating material.
According to a preferred embodiment, the material forming the gas nozzle is an insulating material. The inventors have found that in this preferred case, the scheme of the present application can be performed more stably.
According to another preferred embodiment, the material forming the gas nozzle 2 is a conductive material, and the outlet position of the gas nozzle 2 does not overlap with the arc surface electrode 3 in the vertical direction.
Preferably, the electrical conductivity of the conductive material forming the gas nozzle 2 is >1 MS/m, preferably >10 MS/m; the thermal conductivity is >10 W/(m·° C.), preferably >50 W/(m·° C.).
Preferably, the material forming the electrodes is a conductive material.
More preferably, the conductive material forming the electrode is selected from at least one of 316L stainless steel, tungsten-cerium alloy, nickel-chromium alloy, zinc-copper alloy, copper-chromium alloy, nickel-copper alloy, cobalt-nickel alloy, cobalt-cadmium alloy, and graphite. The material forming the electrode can also be other high-temperature resistant and arc corrosion resistant conductive materials. The material forming the electrode can also be other high-temperature resistant and arc corrosion resistant conductive materials.
Preferably, the electrode is connected with the base through an active connection mechanism, so that the electrode can freely adjust the position in the lower area of the base.
More preferably, the electrode is connected with the base through an active connection mechanism, so that the electrode can be adjusted in position in the vertical direction and the horizontal direction.
Preferably, the active connection mechanism is vertically connected to the base.
More preferably, the active connection mechanism may also be connected to the base non-perpendicularly.
Preferably, the electrode is rotatably connected with the active connection mechanism, so that the electrode can rotate freely to adjust the angle.
More preferably, the electrode is rotatably connected with the active connection mechanism, so that the electrode can rotate to adjust an included angle with the vertical direction.
Preferably, the included angle θ in the extension line of the symmetry axis of each two arc surface electrodes 3 in the symmetrical position is 5°-160°.
Preferably, the gliding arc plasma reactor is used for methane conversion reaction, and the included angle θ between the extension lines of the symmetry axes of each two arc surface electrodes 3 in the symmetrical position is 10°-90°, and more preferably 30°-60°.
The gliding arc plasma reactor provided by the present invention can enable the raw material gas to pass through the discharge area formed by the electrodes more intensively, thereby effectively increasing the gas flow passing through the discharge area and improving the conversion efficiency of reactants.
Preferably, the material forming the outer cylinder of the gliding arc plasma reactor is selected from at least one of an insulating material, a conductive material, and a conductive material provided with an insulating liner.
More preferably, the material forming the outer cylinder of the gliding arc plasma reactor is an insulating material or a conductive material provided with an insulating lining.
Further preferably, the insulating material forming the outer cylinder is selected from at least one of ordinary glass, quartz glass, and corundum.
In the present invention, on the premise of avoiding the contact between the electrode and the outer cylinder of the gliding arc plasma reactor, the material forming the outer cylinder can also be a conductive material.
In the present invention, the shape of the outer cylinder of the gliding arc plasma reactor is not particularly limited, and may be any shape that can provide a closed space for the reactor, such as a cylindrical shape, a rectangular shape, or any other shape that can achieve the aforementioned object of the present invention.
Preferably, a lower reaction zone capable of being filled with catalyst is provided downstream of the gliding arc plasma generator.
Preferably, the material forming the lower reaction zone is a metallic material.
More preferably, the lower reaction zone is tapered, which is more favorable for the distribution of the reaction gas.
Preferably, the proportional relationship among the length d2 of the discharge area, the length d4 of the spacing region and the height d5 of the lower reaction zone satisfies: 1:0.1-0.8:0.5-1.5; the length d4 of the spacing region represents the distance between the bottom of the discharge area and the top of the lower reaction zone.
The gliding arc plasma reactor provided by the present invention can be filled with a catalyst capable of catalyzing the hydrogenation conversion of alkyne to olefin, and the catalyst is preferably filled in the lower reaction zone of the reactor.
The gliding arc plasma reactor provided by the present invention can realize continuous and stable reaction under higher reactant conversion efficiency, and compared with a traditional process for preparing olefin from methane, no CO2 is generated; the ignition and explosion risk is avoided; and the reactor is safer and more environmentally friendly.
As previously mentioned, the second aspect the present invention provides a method for converting methane by means of plasma, the method being carried out in a gliding arc plasma reactor as described in the first aspect, the method comprising:
According to a particularly preferred embodiment, under plasma discharge conditions, a reaction gas containing methane is introduced into the gliding arc plasma reactor through the reactor inlet 1, so that the reaction gas passes through the discharge area formed by the arc surface electrodes 3 to carry out a methane conversion reaction, and the products obtained after the reaction are led out of the gliding arc plasma reactor through the product outlet 5.
The reaction conditions involved in converting methane into olefins in the gliding arc plasma reactor provided by the present invention are not particularly limited, and can be performed in various conditions involved in plasma conversion methods conventionally used in the art, and the conditions involved in converting methane into olefins are exemplified in the examples section of the present invention, and those skilled in the art should not be construed as limiting the present invention.
The gliding arc plasma reactor provided by the present invention has no particular limitation on the concentration of methane in the reaction gas at the reactor inlet, and for example, the concentration of methane in the gas may be 0.01-100 vol %, and may be, for example, 5 vol %, 10 vol %, 15 vol %, 20 vol %, 25 vol %, 30 vol %, 35 vol %, 40 vol %, 45 vol %, 50 vol %, 55 vol %, 60 vol %, 65 vol %, 70 vol %, 75 vol %, 80 vol %, 85 vol %, 90 vol %, 95 vol %.
According to another preferred embodiment, the method further comprises: the reaction gas passes through a discharge area formed by the arc surface electrode 3 and then passes through a lower reaction zone 4 to carry out methane conversion reaction.
Preferably, the lower reaction zone 4 is a reaction zone capable of being provided with a catalyst bed layer, and the flow rate of the reaction gas containing methane is such that the space velocity when passing through the lower reaction zone in the gliding arc plasma reactor is 1000-10000 h−1, and more preferably 5000-8000 h−1.
Preferably, the conditions of the methane conversion reaction comprise: the discharge voltage U1 is 1.0-5.0 kV, and the discharge current is 100-3000 mA; the proportional relationship between the flow rate V1 of the reaction gas passing through the minimum distance D2 between every two arc surface electrodes 3 at the symmetrical position and the discharge voltage U1 is as follows: V1:U1=50-100:1.
Preferably, the conditions of the methane conversion reaction include: the discharge voltage U1 is 2.0-5.0 kV, and the discharge current is 1000-3000 mA.
Preferably, the proportional relationship between the flow rate V1 of the reaction gas passing through the minimum distance D2 between every two arc surface electrodes 3 at the symmetrical position and the discharge voltage U1 is as follows: V1:U1=50-80:1, more preferably V1:U1=60-80:1.
Preferably, the catalyst in the catalyst bed comprises a Ti oxide doped carrier and an active component loaded on the carrier, wherein the active component contains the first active component and the second active component, the first active component is selected from at least one of non-noble metals in the VIII group and metals in the IB group, the second active component is selected from at least one of noble metals in the VIII group, and the weight ratio of the first active component to the second active component calculated by metal elements is 0.1-200:1.
More preferably, the molar ratio of L acid to B acid in the Ti oxide doped carrier is 0.1-50:1.
Preferably, the Ti oxide doped carrier is selected from at least one of Ti oxide doped Al2O3, Ti oxide doped SiO2, Ti oxide doped MgO, and Ti oxide doped molecular sieve.
Preferably, in the Ti oxide doped carrier, the doping amount of the Ti oxide is 0.1-10 wt % based on the total weight of the carrier.
Preferably, the first active component is selected from at least one of Cu, Ag, Au, Ni and Fe.
Preferably, the second active component is selected from at least one of Pt, Rh, Pd and Ir.
Preferably, the weight ratio of the first active component to the second active component calculated by the metal element is 0.1-10:1.
Preferably, the weight ratio of the first active component to the total weight of the catalyst is 0.1-2:100, and the weight of the first active component is calculated by metal elements.
According to a preferred embodiment, the reaction gas is a gas obtained by mixing methane with a carrier gas.
Preferably, the carrier gas is hydrogen.
Preferably, the feed rate of methane is 0.5-5.0 L/min and the feed rate of hydrogen is 1.0-5.0 L/min; more preferably, the feed rate of methane is 0.5-2.5 L/min and the feed rate of hydrogen is 1.0-2.5 L/min.
According to a preferred embodiment, the method further comprises: the product withdrawn from the product outlet 5 is subjected to the first separation to obtain an olefin product and the first gaseous feed comprising hydrogen and a carrier gas.
Preferably, the first gaseous material is recycled, with or without separation, back to the gliding arc plasma reactor to continuously carry out the methane conversion reaction.
Preferably, the conditions of the first separation include separation of the carrier gas and hydrogen from the olefin product using at least one selected from the group consisting of membrane separation, cryogenic separation, and pressure swing adsorption processes.
Preferably, the method further comprises: and carrying out the second separation on the system product to obtain a carbodiolefin and a carbon tetraolefins respectively.
Preferably, the second separation operation comprises separating the olefin products to obtain ethylene, ethane, carbon tetraolefins and carbon tetraalkane.
More preferably, the conditions of the second separation comprise separation by a rectification process.
Another preferred embodiment of the present application for converting methane to olefins using the gliding arc plasma reactor described above is provided below:
In the present invention, after the reaction gas passes through the discharge area formed by the electrodes, the reaction gas carries heat generated by discharge and reactants to enter the lower reaction zone, the heat can provide heat required by the catalyst bed layer in the lower reaction zone, the catalyst bed layer does not need to be additionally heated, and the low energy consumption can be reduced on the premise of not influencing the conversion efficiency.
The present invention will be described in detail below by way of examples.
In the following examples, the raw materials are all commercially available unless otherwise specified. The remaining process parameters and equipment parameters in each example are set to be the same unless otherwise specified.
In the following examples, the methane conversion, ethylene selectivity, ethane selectivity, acetylene selectivity, hydrocarbon selectivity above C3, and carbon deposition are calculated according to the following formulas:
Dissolving palladium nitrate in deionized water to form a palladium nitrate solution (the palladium content is 18 wt %), dissolving copper nitrate in deionized water to form a copper nitrate solution (the copper content is 30 wt %), wherein the palladium nitrate solution and the copper nitrate solution are mixed according to the mixing ratio that the palladium loading accounts for 0.5 wt % of the catalyst mass and the copper loading accounts for 1 wt % of the catalyst mass, adopting a TiO2—Al2O3 carrier, adopting an excess impregnation method, mixing the two solutions, impregnating for 12 h, drying for 4 h at 80° C. by rotary evaporation, then further drying for 8 h at 120° C. in an oven, then placing in a muffle furnace, and roasting for 5 h at 450° C. to obtain a catalyst 1, wherein the chemical composition of the catalyst is as follows:
Examples 1 to 4 are all carried out using the process scheme shown in
In examples 1 to 4, the methane conversion reaction is performed using a gliding arc plasma reactor, and the electrode gliding arc generator used is a gliding arc plasma generator and the electrode used is an arc surface electrode.
The specific structure and structural parameters of the reactor are as follows:
The operating conditions of the gliding arc plasma reactor in this example are as follows:
This example uses a gliding arc plasma reactor similar to that of example 1 for the methane conversion reaction, except that in this example:
In this example, the discharge power is adjusted to 250 W, the voltage is 1.8 kV, the discharge frequency is 25.5 kHz, the gas inlet flow is 0.5 L/min of methane and 2 L/min of hydrogen;
The rest of the process is the same as in example 1.
The tail gas is analyzed, and the result is as follows: the conversion rate of methane is 48.7%, the selectivity of ethylene is 89.2%, the selectivity of ethane is 4.7%, the selectivity of hydrocarbons above C3 is 6.1%, and no obvious carbon deposition exists.
This example uses a gliding arc plasma reactor similar to that of example 1 for the methane conversion reaction, except that in this example:
In this example, the discharge power is adjusted to 280 W, the voltage is 3.5 kV, the discharge frequency is 17.5 kHz, the gas inlet flow is 1.75 L/min of methane and 2.3 L/min of hydrogen;
The rest of the process is the same as in example 1.
The tail gas is analyzed, and the result is as follows: the conversion rate of methane is 47.5%, the selectivity of ethylene is 91.3%, the selectivity of ethane is 5.6%, the selectivity of hydrocarbons above C3 is 3.1%, and no obvious carbon deposition exists.
This example uses a gliding arc plasma reactor similar to that of example 1 for the methane conversion reaction, except that in this example:
In this example, the discharge power is adjusted to 350 W, the voltage is 4.2 kV, the discharge frequency is 25.5 kHz, the gas inlet flow is 2.9 L/min of methane and 3.8 L/min of hydrogen;
The rest of the process is the same as in example 1.
The tail gas is analyzed, and the result is as follows: the conversion rate of methane is 48.7%, the selectivity of ethylene is 90.5%, the selectivity of ethane is 6.7%, the selectivity of hydrocarbons above C3 is 2.8%, and no obvious carbon deposition exists.
Examples 5 to 8 are all carried out using the process scheme shown in
In examples 5 to 8, the methane conversion reaction is carried out using a gliding arc plasma reactor, using a tubular electrode gliding arc generator as the electrode gliding arc generator, using a tubular electrode as the electrode, and the average thickness of the electrode material (excluding any coating layer that may be present) is 2 mm.
The specific structure and structural parameters of the reactor are as follows:
The operating conditions of the gliding arc plasma reactor in this example are as follows:
This example uses a gliding arc plasma reactor similar to that of example 5, except that in this example:
In this example, the discharge power is adjusted to 257 W, the voltage is 1.9 kV, the discharge frequency is 14.9 kHz, the gas inlet flow is 2.1 L/min of methane and 2.8 L/min of hydrogen;
The rest of the process is the same as in example 5.
The tail gas is analyzed, and the result is as follows: the conversion rate of methane is 51.2%, the selectivity of ethylene is 90.1%, the selectivity of ethane is 5.4%, the selectivity of hydrocarbons above C3 is 3.3%, and no obvious carbon deposition exists.
This example uses a gliding arc plasma reactor similar to that of example 5, except that in this example:
In this example, the discharge power is adjusted to 149 W, the voltage is 2.5 kV, the discharge frequency is 26.5 kHz, the gas inlet flow is 1.1 L/min of methane and 1.6 L/min of hydrogen;
The rest of the process is the same as in example 5.
The tail gas is analyzed, and the result is as follows: the conversion rate of methane is 52.1%, the selectivity of ethylene is 88.4%, the selectivity of ethane is 6.7%, the selectivity of hydrocarbons above C3 is 4.9%, and no obvious carbon deposition exists.
This example uses a gliding arc plasma reactor similar to that of example 5, except that in this example:
The coating is carried out as described in the preferred embodiment above, with the Al2O3—ZnO—HfO2 films applied sequentially from the bottom, with 100 single atomic layer deposited metal oxide thin films per coating.
The rest of the process is the same as in example 5.
The tail gas is analyzed, and the result is as follows: the conversion rate of methane is 52.3%, the selectivity of ethylene is 93.3%, the selectivity of ethane is 2.3%, the selectivity of hydrocarbons above C3 is 4.4%, and no obvious carbon deposition exists.
From the results, when the gliding arc plasma reactor provided by the present invention is used for converting methane to generate olefin, the conversion rate of methane can be obviously improved, the selectivity of ethylene in the product can be improved, and carbon deposition can be obviously reduced compared with the prior art. The reactor provided by the present invention can realize continuous and stable reaction under higher reactant conversion efficiency, and compared with a traditional process for preparing olefin from methane, no CO2 is generated; the ignition and explosion risk is avoided; and the reactor is safer and more environmentally friendly.
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the present invention, many simple modifications can be made to the technical solution of the invention, including various technical features being combined in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202111565360.2 | Dec 2021 | CN | national |
| 202111565366.X | Dec 2021 | CN | national |
| 202111565369.3 | Dec 2021 | CN | national |
| 202111567199.2 | Dec 2021 | CN | national |
| 202111567211.X | Dec 2021 | CN | national |
| 202111567216.2 | Dec 2021 | CN | national |
| 202111567218.1 | Dec 2021 | CN | national |
| 202111567219.6 | Dec 2021 | CN | national |
| 202111567220.9 | Dec 2021 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2022/140057 | 12/19/2022 | WO |
