Method for synthesizing acetylene through cooperation of DBD plasma and catalysis and application

Abstract

The invention discloses a method for synthesizing acetylene through cooperation of normal-pressure DBD plasma and catalysis and application of the method. Gas containing methane is fed into a novel normal-pressure DBD plasma acetylene synthesis device with the active catalyst synergistic effect, and effective synthesis of acetylene products is achieved under the mild reaction conditions of normal temperature and normal pressure; as a comparative analysis, the currently reported acetylene synthesis is mainly a calcium carbide method preparation process with high energy consumption and large pollution; the acetylene synthesis process is also carried out by a methane semi-oxidation method at the reaction temperature of 1350-1450 DEG C, so that the energy consumption is high, and the selectivity is general; according to the method disclosed by the invention, under the catalytic synergistic effect of the normal-pressure and normal-temperature DBD plasma and the active oxide-based composite catalyst filler, acetylene can be effectively synthesized under mild conditions, and the energy consumption is obviously reduced; through further regulation and control tests and optimization under the action of mild condition process technical parameters, the carbon molar selectivity of the acetylene product can reach 47.02%, and the sum of the carbon molar selectivity of the carbon diunsaturated hydrocarbon acetylene and the carbon molar selectivity of the ethylene reaches 62.70%.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of synthetic acetylene, and particularly relates to a new method and application for synthesizing acetylene by the catalytic synergistic effect of DBD plasma and an active catalyst, and an acetylene synthesis device thereof. Under mild conditions of normal temperature and pressure, excellent carbon molar selectivity of the target product acetylene can be obtained; the energy consumption of the acetylene synthesis technology and the new process of the present method is low. Background Art

[0002] Acetylene is one of the chemical platform raw materials for substances such as 1,4-butanediol, vinyl acetate, and polyvinyl alcohol, and has received increasing attention in the chemical industry and new materials industry in recent decades. At present, there are various methods for producing acetylene, mainly including the calcium carbide method, the partial oxidation method of natural gas, and the method of producing acetylene by thermal plasma cracking of coal, etc. The raw material source of the calcium carbide method for producing acetylene is rich, but the pollution is very serious, and the process of preparing calcium carbide also consumes a lot of electric energy; since methane is a thermodynamically very stable molecule, the method of partial oxidation of natural gas to produce acetylene requires at least above 1230 °C to decompose a small amount of methane into acetylene and hydrogen, and the operating temperature of the industrial process of the semi-oxidation method for synthesizing acetylene is usually 1350 - 1450 °C; moreover, there are many by-products, and the selectivity of acetylene is low; a large amount of carbon black is also produced as a by-product, thereby reducing the selectivity of acetylene.

[0003] The Sichuan Vinylon Works introduced a natural gas to acetylene device from BASF Company of Germany in the 1970s. This device mainly includes five basic processes: raw material gas preheating, cracking reaction, product gas washing and compression, concentration of product acetylene, and waste treatment and recovery; in these five processes, 70% of the raw material methane gas is used for combustion heating, so that the temperature of the cracking reactor is usually 1350 - 1450 °C, methane cracks to generate acetylene and hydrogen, and the cracked tail gas enters the washing and compression device. At this time, the cracked gas needs to be quenched from 1400 °C to 80 °C, which requires a large amount of cooling medium, resulting in a large amount of heat loss; moreover, during the process that the cracked gas cannot be cooled in time, since the Gibbs free energy of acetylene is higher than that of carbon black, acetylene will further crack to generate carbon black; the selectivity of acetylene is low, and at the same time, the energy consumption of this synthesis process is high; there is an urgent need for improvement.

[0004] The technology of producing acetylene by pyrolyzing coal with hot plasma is to use a plasma pyrolysis generator to generate hydrogen plasma with an average temperature of 4000K (3727°C), and then carry out chemical reactions with the pulverized coal jet formed by a small amount of hydrogen carrying pulverized coal in the plasma reactor to produce a mixed gas containing acetylene. After the mixed gas is quenched by the quenching device of the reactor, it enters the gas separation device. After separation, the product acetylene can be obtained, and by-products such as hydrogen, carbon monoxide, and a small amount of methane, olefin gas, and coal char are also produced. From 2002 to 2016, Xinjiang Tianye Co., Ltd. conducted industrial experiments on the 5MW hydrogen hot plasma pyrolysis coal to produce acetylene device. There are still problems of stable operation that need to be solved urgently, and the acetylene yield is slightly higher than 10%; the reaction temperature of this process is higher than 3000°C; the energy consumption is high and the acetylene selectivity is low.

[0005] In view of this, based on a large number of research experiments, the present invention is specifically proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide a new method for synthesizing acetylene by the catalytic synergy of atmospheric pressure DBD plasma and active catalyst and its application to acetylene synthesis under mild conditions. In the process of synthesizing acetylene, the present invention systematically and deeply studies the technical method of the catalytic synergy of atmospheric pressure DBD plasma and active catalyst. Reviewing the comparative technology, traditional thermal plasma needs to induce the cracking of methane at a relatively high temperature to generate free radicals such as methyl, and these free radicals further combine to form various reaction products. Due to the relatively high reaction temperature, during the reaction process, it is easy to cause the product to dehydrogenate deeply to produce coke, resulting in the blockage of the thermal plasma reactor and the inability of the reaction device to operate stably. Therefore, by exploring the catalytic synergy of atmospheric pressure DBD plasma and active catalyst in the field of acetylene synthesis, it has been successfully studied that under relatively mild conditions of atmospheric pressure and near room temperature, by combining DBD plasma with an active catalyst composite material, the target product of synthesized acetylene has a relatively high carbon molar selectivity; the results of this work provide an effective solution to multiple problems caused by the reaction temperature higher than 1400 degrees in the traditional semi-oxidation method for synthesizing acetylene.

[0007] In order to achieve the above object of the present invention, the following technical solutions are specifically adopted:

[0008] The present invention provides a method and application for catalytic synergy of DBD plasma and active catalyst to synthesize acetylene, which is characterized in that the method for catalytic synergy of DBD plasma and active catalyst to synthesize acetylene includes the following steps and applications:

[0009] An oxide-based composite catalyst is filled in the new DBD plasma device. Under normal pressure and room temperature conditions, a gas containing methane flows through the new DBD plasma synthesis device to effectively synthesize acetylene under the synergistic action of room-temperature DBD plasma and the oxide-based composite catalyst. The composition of the product is detected and calculated by gas chromatography instrument analysis method; through further regulation tests and optimizations under mild conditions, the carbon molar selectivity of the acetylene product can reach 47.02%, and the sum of the carbon molar selectivities of the C2 unsaturated hydrocarbons acetylene and ethylene reaches 62.70%; the present invention utilizes the characteristics of a high-energy excitation source of atmospheric pressure DBD plasma and the generation of highly active species, and effectively synthesizes acetylene under the synergistic action with an active catalyst and under relatively mild conditions. The main product is acetylene, and the by-product is ethylene.

[0010] The new DBD plasma acetylene synthesis device mainly includes a plasma power supply, a reaction tube, a control system for the synthesis acetylene reaction process technical parameters, a product collection system, a product analysis system and other components; the plasma power supply includes an inner electrode and an outer electrode. The inner electrode is located on the axis of the reaction tube, and the outer electrode surrounds the outer periphery of the reaction tube; the overlapping area of the inner electrode, the outer electrode and the reaction tube is the plasma discharge area; the plasma discharge area is filled with an oxide-based composite catalyst.

[0011] The reaction tube includes an air inlet and an air outlet; the air inlet is located upstream of the plasma discharge area; the air outlet is located downstream of the plasma discharge area; the reaction tube material includes quartz, insulating ceramic, corundum, SiC or metal; the inner electrode material is tungsten, iron and copper; the inner electrode is directly connected to the high-voltage power line; the outer electrode is aluminum foil or copper foil; the reaction tube is a straight tube, a U-shaped tube or a spiral ring tube; the oxide-based composite catalyst is one or a mixture of more of aluminum oxide, magnesium oxide, zinc oxide-based composite compound M1Ox, manganese oxide-based complex M2Oy, iron oxide, and titanium dioxide.

[0012] The method and application of the catalytic synergistic synthesis of acetylene by atmospheric pressure DBD plasma. The DBD plasma is mainly regulated by an excitation power supply, and the working mode is mainly a constant current mode; the input voltage range of the new synthesis reaction device is from 2V to 230V, preferably from 5V to 120V, and further preferably from 10V to 80V; the output current is 4A; the frequency is high frequency (5kHz - 50kHz).

[0013] The method and application for the synergistic synthesis of acetylene by atmospheric pressure DBD plasma and catalysis use a methane-containing gas as the reaction raw material gas, with the methane content ranging from 0.1% to 100%; preferably from 2% to 95%, and more preferably from 10% to 80%. The reaction raw material gas is a methane-containing gas or a mixture of methane and other gases. In the mixture, the main components are inert gases or other gases. The inert gases include at least one of nitrogen, helium, neon, and argon; the other gases may also include one or more of ethane, hydrogen, ethylene, carbon dioxide gas, or a small amount of oxygen. In the experiments related to this invention application, the main flow rate of the reaction raw material gas is 10 - 200 mL / min, and more preferably 20 - 80 mL / min.

[0014] The main product of the novel method for the synergistic synthesis of acetylene by DBD plasma and catalysis under normal temperature and pressure of this invention is acetylene, with ethylene (one of the C2 unsaturated hydrocarbons) as a by-product. Compared with the prior art, the beneficial effects of this invention at least include:

[0015] (1) By coupling atmospheric pressure DBD plasma with an oxide-based composite catalyst in the method of this invention, their advantages are complementary. The energy provided makes it easier to activate the raw material methane, facilitating the elongation and breaking of the C-H bond. At the same time, the activated CHx intermediate can undergo a series of processes such as adsorption, dissociation, reaction, and desorption on the oxide-based composite catalyst. Compared with traditional technologies (>1200 °C), this method can effectively synthesize acetylene under mild reaction conditions (below 200 °C), with ethylene as a by-product, and overcomes the disadvantage of excessive carbon deposition in the high-temperature synthesis of acetylene by the traditional partial oxidation method; there is almost no carbon deposition.

[0016] (2) In the process of this invention, by using the synergistic effect of atmospheric pressure DBD plasma and catalysis, acetylene can be directly synthesized as the main product under mild conditions. The carbon molar selectivity of acetylene reaches 47.02%, with ethylene as a by-product. The sum of the carbon molar selectivities of the C2 unsaturated hydrocarbons acetylene and ethylene reaches 62.69%; the reaction temperature of the synthesis system is mild, and the single-pass conversion rate of the raw material can reach about 20%; there is almost no carbon deposition during the reaction process.

[0017] (3) Compared with the existing reaction systems for the high-temperature synthesis of acetylene, the test reaction conditions of the reaction system of this invention are mild, with low energy consumption and good acetylene selectivity; compared with the processes of the high-temperature partial oxidation method and the high-temperature thermal plasma method for synthesizing acetylene, the method and application of this invention have obvious advantages.

[0018] This invention can achieve the synthesis of acetylene under mild conditions by using the synergistic effect of normal temperature and pressure DBD plasma and catalysis; it has advantages such as good carbon molar selectivity of acetylene, high carbon atom utilization rate, and high energy utilization rate. Therefore, it can provide new ideas for the synthesis of acetylene under mild conditions and has good application reference value. Description of the Drawings

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art.

[0020] Figure 1 It is a bar graph of the carbon molar selectivity of the acetylene products synthesized in Examples 1-3 and the comparative example;

[0021] Figure 2 It is a bar graph of the carbon molar selectivity of the acetylene products synthesized in Examples 4-5 and Comparative Example 1;

[0022] Figure 3 It is a bar graph of the carbon molar selectivity of the acetylene products synthesized in Examples 6-8 and Comparative Example 2;

[0023] Figure 4 It is a bar graph of the carbon molar selectivity of the acetylene products synthesized in Examples 6 and 9 and Comparative Example 2;

[0024] Figure 5 It is a bar graph of the carbon molar selectivity of the acetylene products synthesized in Examples 10-11 and Comparative Example 2. The methods and applications of the specific implementation process

[0025] The following will describe in detail the embodiments of the technical solutions of the present invention in combination with Comparative Examples 1-2 and Examples 1-11; the following examples and comparative examples are only used to more clearly illustrate the technical solutions and applications of the present invention; as examples.

[0026] It should be noted that unless otherwise specified, the technical terms or scientific terms used in this application should have the ordinary meanings understood by those skilled in the art to which the present invention belongs.

[0027] Comparative Example 1

[0028] This Comparative Example 1 is for the synthesis of acetylene by DBD plasma at atmospheric pressure. The reaction process of the atmospheric pressure DBD plasma synthesis includes the following steps:

[0029] The reaction test conditions adopted are: atmospheric pressure P = 0.1 MPa = 100 KPa, the input voltage is 30 V, which is converted to more than 7000 V through the power conversion system, the reaction raw material gas is 25% CH4 and 75% Ar, and the total flow rate is 40 mL / min; the reaction tube is a straight tube, the outer tube has an outer diameter of 12 mm, an inner diameter of 10 mm, the discharge area length is 20 mm, a single-layer dielectric barrier structure and no filling material, and the reaction system temperature is near room temperature; when the DBD plasma-assisted methane activation and conversion reaction reaches stability, the reaction time is 60 min; analyzing the product and raw material mixture, and through data analysis, the reaction result is: the carbon molar selectivity of acetylene is 16.1%, and the sum of the carbon molar selectivities of acetylene and ethylene in the total products is 21.5%;

[0030] Comparative Example 2

[0031] This Comparative Example 2 is a method for synthesizing acetylene by the action of atmospheric pressure DBD plasma and inert SiO2 filling dielectric material. The technological process for synthesizing acetylene includes the following steps:

[0032] The reaction tube used is a straight tube. The outer tube has an outer diameter of 12 mm and an inner diameter of 10 mm. The material of the reaction tube is corundum. The input voltage is 30 V, which is converted to more than 7000 V through a power conversion system. The atmospheric pressure P = 0.1 MPa. The reaction raw material gas is 80% Ar and 20% CH4, with a total flow rate of 40 mL / min. The length of the discharge region is 20 mm. Under the test conditions of a single-layer dielectric barrier structure and filling material being inert SiO2, when the DBD plasma-assisted raw material activation and conversion reaction reaches stability, the reaction time is 60 min. Analyze the product and raw material mixture, and through data analysis, the reaction results are as follows: The carbon molar selectivity of acetylene is 16.9%, and the carbon molar selectivity of acetylene and ethylene in the total products is 25.9%.

[0033] Example 1

[0034] This Example 1 is a new method for synthesizing acetylene by the synergistic effect of atmospheric pressure DBD plasma and active catalytic material, and effectively synthesizes acetylene under mild conditions of atmospheric pressure and near room temperature. The implemented reaction process and data analysis include:

[0035] The reaction test conditions used are: atmospheric pressure P = 0.1 MPa = 100 KPa, the input voltage is 30 V, which is converted to more than 7000 V through a power conversion system. The reaction raw material mixture gas is 10% CH4 and 90% Ar, with a total flow rate of 40 mL / min. The reaction tube is a straight tube. The outer tube has an outer diameter of 12 mm and an inner diameter of 10 mm. The main material of the reaction tube is corundum-based. The single-layer dielectric barrier structure and filling catalytic material are active zinc oxide-based composite catalyst M1Ox. The reaction temperature is near room temperature, and the length of the discharge region is 20 mm. When the atmospheric pressure DBD plasma and catalytic synergistic promotion of the raw material methane activation and conversion reaction reaches stability, the reaction time is 60 min. Analyze the product and raw material mixture, and through data analysis, the reaction results are as follows: The carbon molar selectivity of acetylene is 22.6%, and the carbon molar selectivity of acetylene and ethylene in the total products is 30.1%.

[0036] Example 2

[0037] This example is a new method for synthesizing acetylene by the synergistic effect of room temperature and atmospheric pressure DBD plasma and catalysis, and synthesizes acetylene under mild conditions. The implemented reaction process and data analysis include:

[0038] The reaction tube used is a straight tube. The outer tube has an outer diameter of 12 mm and an inner diameter of 10 mm. At normal temperature and normal pressure P = 0.1 MPa, the input voltage is 30 V, which is converted to over 7000 V through a power conversion system. The reaction raw material gas is 20% CH4 and 80% Ar, the total flow rate is 40 mL / min, the discharge area length is 20 mm, under the test conditions of a single-layer dielectric barrier structure and filled with a catalytic material MgO sample. When the synergistic effect of atmospheric pressure DBD plasma and an active catalyst promotes the activation and conversion reaction of the methane-containing raw material gas to reach stability, the reaction time is 60 min. Analyze the product and raw material mixture, and through data analysis, the reaction results are as follows: the carbon molar selectivity of acetylene is 16.9%, and the carbon molar selectivity of acetylene and ethylene in the total products is 28.3%.

[0039] Example 3

[0040] This example is a new method for synthesizing acetylene by the synergistic effect of atmospheric pressure DBD plasma and catalysis, and synthesizes acetylene under mild conditions. The implemented reaction process and data analysis include:

[0041] The reaction tube used is a straight tube. The outer tube has an outer diameter of 12 mm and an inner diameter of 10 mm. The material of the reaction tube is corundum. At normal temperature and normal pressure P = 0.1 MPa, the input voltage is 30 V, which is converted to over 7000 V through a power conversion system. The reaction raw material gas is 10% Ar and 90% CH4, the total flow rate is 40 mL / min, the discharge area is 20 mm, under the test conditions of a single-layer dielectric barrier structure and filled with a catalytic material M1Ox zinc-based compound catalyst. When the synergistic effect of atmospheric pressure DBD plasma and an active catalyst promotes the activation and conversion reaction of the methane-containing raw material gas to reach stability, the reaction time is 60 min. Analyze the product and raw material mixture, and through data analysis, the reaction results are as follows: the carbon molar selectivity of acetylene is 20.9%, and the carbon molar selectivity of acetylene and ethylene in the total products is 27.9%.

[0042] Comparing the synthesis reaction results of the above Examples 1 to 3 with Comparative Example 1, as Figure 1 shown; in the process of synthesizing acetylene by the synergistic effect of atmospheric pressure DBD plasma and catalysis, the carbon molar selectivity of acetylene in Comparative Example 1 is 16.1%, and the carbon molar selectivity of acetylene in Example 1 is 22.6%, with a relative increase of 40.3%. Further regulation and optimization of the main parameters such as the technical process and active catalyst will be carried out in Examples 4 - 11, and it is expected to obtain significantly optimized carbon molar selectivity of acetylene and excellent carbon molar selectivity of C2 unsaturated hydrocarbons (acetylene and ethylene) under mild synthesis conditions.

[0043] Example 4

[0044] This example is a new method for synthesizing acetylene by the synergistic effect of room-temperature and atmospheric-pressure DBD plasma and catalysis, and acetylene is synthesized under mild conditions. The implementation of the reaction process and data analysis include:

[0045] The reaction tube used is a straight tube. The outer tube has an outer diameter of 12 mm and an inner diameter of 10 mm. The material of the reaction tube is corundum. At room temperature and atmospheric pressure P = 0.1 MPa, the input voltage is 30 V, which is converted to more than 7000 V through a power conversion system. The reaction raw material gas is 80% Ar and 20% CH4, the total flow rate is 40 mL / min, the discharge area is 20 mm, the single-layer dielectric barrier structure and the filled catalytic material are zinc oxide-based composite compound M1O x Under the test conditions, when the synergistic effect of atmospheric-pressure DBD plasma and active catalyst promotes the activation and conversion reaction of methane-containing raw material gas to reach stability, the reaction time is 60 min. Analyze the product and raw material mixture, and through data analysis, the reaction results are as follows: the carbon molar selectivity of acetylene is 31.1%, and the carbon molar selectivity of acetylene and ethylene in the total product is 41.4%.

[0046] Example 5

[0047] This example is a new method for synthesizing acetylene by the synergistic effect of room-temperature and atmospheric-pressure DBD plasma and catalysis, and acetylene is synthesized under mild conditions. The implementation of the reaction process and data analysis include:

[0048] The reaction tube used is a straight tube. The outer tube has an outer diameter of 12 mm and an inner diameter of 10 mm. The material of the reaction tube is corundum. At room temperature and atmospheric pressure P = 0.1 MPa, the input voltage is 30 V, which is converted to more than 7000 V through a power conversion system. The reaction raw material gas is 25% Ar and 75% CH4, the total flow rate is 40 mL / min, the discharge area is 20 mm, the single-layer dielectric barrier structure and the filled catalytic material are zinc oxide-based composite compound M1O x Under the test conditions, when the synergistic effect of atmospheric-pressure DBD plasma and active catalyst promotes the activation and conversion reaction of methane-containing raw material gas to reach stability, the reaction time is 60 min. Analyze the product and raw material mixture, and through data analysis, the reaction results are as follows: the carbon molar selectivity of acetylene is 30.2%, and the carbon molar selectivity of acetylene and ethylene in the total product is 40.3%.

[0049] Comparing the synthesis reaction results of the above Examples 4 to 5 with Comparative Example 1, as Figure 2As shown; in the process of synthesizing acetylene by the synergistic effect of atmospheric pressure DBD plasma and catalysis, the carbon molar selectivity of acetylene in Comparative Example 1 was 16.1%, and the carbon molar selectivity of acetylene in Example 4 was 31.1%, with a relative increase of 93.2%; the carbon molar selectivity of C2 unsaturated hydrocarbons (acetylene and ethylene) increased from 21.5% to 41.4%, with a relative increase of 92.6%; the technical process and main parameters such as the active catalyst will be further regulated and optimized in Examples 6 - 11, and it is expected to obtain significantly optimized carbon molar selectivity of acetylene and excellent carbon molar selectivity of C2 unsaturated hydrocarbons (acetylene and ethylene) under mild synthesis conditions.

[0050] Example 6

[0051] This example is a new method for synthesizing acetylene by the synergistic effect of normal temperature and pressure DBD plasma and catalysis, and synthesizing acetylene under mild conditions; the implemented reaction process and data analysis include:

[0052] The reaction tube used is a straight tube, the outer tube has an outer diameter of 12 mm and an inner diameter of 10 mm. At normal temperature and atmospheric pressure P = 0.1 MPa, the input voltage is 22 V, which is converted to more than 7000 V through a power conversion system. The reaction raw material gas is 75% Ar and 25% CH4, the total flow rate is 40 mL / min, the discharge area is 50 mm, the single-layer dielectric barrier structure and the filled catalytic material are zinc oxide-based composite compound M1O x Under the test conditions of the catalyst, when the synergistic effect of atmospheric pressure DBD plasma and the active catalyst promotes the activation and conversion reaction of the methane-containing raw material gas to reach stability, the reaction time is 60 min; analyzing the product and raw material mixture, the reaction results after data analysis are: the carbon molar selectivity of acetylene is 37.71%, and the carbon molar selectivity of acetylene and ethylene in the total product is 41.01%.

[0053] Example 7

[0054] This example is a new method for synthesizing acetylene by the synergistic effect of normal temperature and pressure DBD plasma and catalysis, and synthesizing acetylene under mild conditions; the implemented reaction process and data analysis include:

[0055] The reaction tube used is a straight tube, the outer tube has an outer diameter of 12 mm and an inner diameter of 10 mm. The material of the reaction tube is corundum. At normal temperature and atmospheric pressure P = 0.1 MPa, the input voltage is 22 V, which is converted to more than 7000 V through a power conversion system. The reaction raw material gas is 75% Ar and 25% CH4, the total flow rate is 40 mL / min, the discharge area is 70 mm, the single-layer dielectric barrier structure and the filled catalytic material are zinc oxide-based composite compound M1O xUnder the test conditions of the catalyst, when the synergistic effect of atmospheric pressure DBD plasma and active catalyst promotes the activation and conversion reaction of methane-containing raw material gas to reach stability, the reaction time is 60 min; analyzing the product and raw material mixture, the reaction results after data analysis are as follows: the carbon molar selectivity of acetylene is 43.22%, and the carbon molar selectivity of acetylene and ethylene in the total product is 57.63%.

[0056] Example 8

[0057] This example is a new method for synthesizing acetylene by using atmospheric temperature and pressure DBD plasma and catalysis synergistically, and synthesizing acetylene under mild conditions; the implemented reaction process and data analysis include:

[0058] The reaction tube used is a straight tube, the outer tube has an outer diameter of 12 mm and an inner diameter of 10 mm. At normal temperature and atmospheric pressure P = 0.1 MPa, the input voltage is 22 V, which is converted to more than 7000 V through a power conversion system. The reaction raw material gas is 75% Ar and 25% CH4, the total flow rate is 40 mL / min, the discharge area is 90 mm, the single-layer dielectric barrier structure and the filled catalytic material are zinc oxide-based composite compound M1O x Under the test conditions of the catalyst, when the synergistic effect of atmospheric pressure DBD plasma and active catalyst promotes the activation and conversion reaction of methane-containing raw material gas to reach stability, the reaction time is 60 min; analyzing the product and raw material mixture, the reaction results after data analysis are as follows: the carbon molar selectivity of acetylene is 47.02%, and the carbon molar selectivity of acetylene and ethylene in the total product is 62.69%.

[0059] Comparing the synthesis reaction results of the above Examples 6 - 8 with Comparative Example 2, as Figure 3 shown; in the process of synthesizing acetylene by atmospheric pressure DBD plasma and catalysis synergistically, the carbon molar selectivity of acetylene in Comparative Example 2 is 16.9%, and the carbon molar selectivity of acetylene in Example 8 is 47.02%, with a relative increase of 178.2%; the carbon molar selectivity of C2 unsaturated hydrocarbons (acetylene and ethylene) increases from 25.9% to 62.69%, with a relative increase of 142.0%; the technical process and main parameters such as active catalyst will be regulated and optimized in further examples, and it is expected to obtain significantly optimized carbon molar selectivity of acetylene and excellent carbon molar selectivity of C2 unsaturated hydrocarbons (acetylene and ethylene) under mild synthesis conditions.

[0060] Example 9

[0061] This example is a new method for synthesizing acetylene by using atmospheric temperature and pressure DBD plasma and catalysis synergistically, and synthesizing acetylene under mild conditions; the implemented reaction process and data analysis include:

[0062] The reaction tube used is a straight tube. The outer tube has an outer diameter of 12 mm and an inner diameter of 10 mm. The material of the reaction tube is corundum. At normal temperature and normal pressure P = 0.1 MPa, the input voltage is 22 V, which is converted to more than 7000 V through the power conversion system. The reaction raw material gas is 75% Ar and 25% CH4, the total flow rate is 40 mL / min, the discharge area is 50 mm, and the single-layer dielectric barrier structure and the filled catalytic material are zinc oxide-based composite and manganese oxide-based composite M1O x -M2O y Under the test conditions of the catalyst, when the synergistic effect of atmospheric pressure DBD plasma and active catalyst promotes the activation and conversion reaction of methane-containing raw material gas to reach stability, the reaction time is 60 min; analyzing the product and raw material mixture, and through data analysis, the reaction result is: 41.04%, and the carbon molar selectivity of acetylene and ethylene in the total product is 54.72%.

[0063] Comparing the synthesis reaction results of Example 6 and Example 9 with Comparative Example 2 above, as Figure 4 shown; in the process of synergistic synthesis of acetylene by atmospheric pressure DBD plasma and catalysis, the carbon molar selectivity of acetylene in Comparative Example 2 is 16.9%, and the carbon molar selectivity of acetylene in Example 9 is 41.0%, with a relative increase of 142.6%; the carbon molar selectivity of C2 unsaturated hydrocarbons (acetylene and ethylene) increases from 25.9% to 54.7%, with a relative increase of 111.2%; the technical process and main parameters such as active catalyst will be regulated and optimized in further examples, and it is expected to obtain significantly optimized carbon molar selectivity of acetylene and excellent carbon molar selectivity of C2 unsaturated hydrocarbons (acetylene and ethylene) under mild synthesis conditions.

[0064] Example 10

[0065] This example is a new method for synergistic synthesis of acetylene by atmospheric pressure DBD plasma and catalysis at normal temperature and pressure, and acetylene is synthesized under mild conditions. The reaction process and data analysis implemented include:

[0066] The reaction tube used is a straight tube. The outer tube has an outer diameter of 12 mm. At normal temperature and normal pressure P = 0.1 MPa, the input voltage is 35 V, which is converted to more than 7000 V through the power conversion system. The reaction raw material gas is 80% Ar and 20% CH4, the total flow rate is 40 mL / min, the discharge area is 20 mm, and the single-layer dielectric barrier structure and the filled catalytic material are zinc oxide-based composite compound M1O xUnder the test conditions of the catalyst, when the activation and conversion reaction of the methane-containing raw material gas is promoted by the synergistic effect of atmospheric pressure DBD plasma and the active catalyst and reaches stability, the reaction time is 60 min; the product and raw material mixture are analyzed, and the reaction results are as follows through data analysis: the carbon molar selectivity of acetylene is 24.2%, and the carbon molar selectivity of acetylene and ethylene in the total product is 32.3%.

[0067] Example 11

[0068] This example is a new method for synthesizing acetylene by using atmospheric temperature and pressure DBD plasma and catalysis synergistically, and synthesizing acetylene under mild conditions; the implemented reaction process and data analysis include:

[0069] The reaction tube used is a straight tube, the outer tube has an outer diameter of 12 mm and an inner diameter of 10 mm, the material of the reaction tube is corundum, at normal temperature and atmospheric pressure P = 0.1 MPa, the input voltage is 30 V, which is converted to more than 7000 V through the power conversion system, the reaction raw material gas is 75% Ar and 25% CH4, the total flow rate is 40 mL / min, the discharge area is 50 mm, the single-layer dielectric barrier structure and the filled catalytic material are zinc oxide-based composite compound M1O x Under the test conditions of the catalyst, when the activation and conversion reaction of the methane-containing raw material gas is promoted by the synergistic effect of atmospheric pressure DBD plasma and the active catalyst and reaches stability, the reaction time is 60 min; the product and raw material mixture are analyzed, and the reaction results are as follows through data analysis: the carbon molar selectivity of acetylene is 30.76%, and the carbon molar selectivity of acetylene and ethylene in the total product is 41.01%.

[0070] The comparison of the synthesis reaction results of the above Examples 10 to 11 and Comparative Example 2 is as Figure 5 shown; in the process of synthesizing acetylene by atmospheric pressure DBD plasma and catalysis synergistically, the carbon molar selectivity of acetylene in Comparative Example 2 is 16.9%, and the carbon molar selectivity of acetylene in Example 11 is 30.76%, with a relative increase of 80.0%; the carbon molar selectivity of C2 unsaturated hydrocarbons (acetylene and ethylene) increases from 25.9% to 41.0%, with a relative increase of 58.3%; the technical process and main parameters such as the active catalyst will be regulated and optimized in further examples, and it is expected to obtain significantly optimized carbon molar selectivity of acetylene and excellent carbon molar selectivity of C2 unsaturated hydrocarbons (acetylene and ethylene) under mild synthesis conditions.

[0071] Analyze the results of the above examples and comparative examples, specifically by Figures 1 to 5From the comparison and analysis of the results, it can be seen that in the process of the present invention, atmospheric pressure DBD plasma and an active catalyst are used in synergy, and acetylene can be directly synthesized as the main product under mild conditions. The carbon molar selectivity of acetylene reaches 47.02%, and ethylene is produced as a by-product; the carbon molar selectivity of C2 unsaturated hydrocarbons (acetylene + ethylene) reaches 62.69%. Compared with Comparative Example 1 and Comparative Example 2, the acetylene selectivity of the synthesis method of the examples of the present application is significantly improved.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

Claims

1. A method and application for synthesizing acetylene by the synergistic action of atmospheric-pressure DBD plasma and active catalyst, characterized in that, The new process technology method and application for synthesizing acetylene by the synergistic action of atmospheric-pressure DBD plasma and active catalyst include the following steps: Fill an oxide-based composite catalyst in the new DBD plasma synthesis device. Under the experimental conditions of atmospheric pressure and normal temperature, pass the gas containing methane through the new DBD plasma synthesis device to effectively synthesize acetylene under the synergistic action of DBD plasma and the oxide-based composite catalyst; the carbon molar selectivity of the acetylene product reaches 47.02%, and the sum of the carbon molar selectivities of the C2 unsaturated hydrocarbons acetylene and ethylene reaches 62.70%.

2. The method and application for synthesizing acetylene by the synergistic action of atmospheric-pressure DBD plasma and active catalyst according to claim 1, characterized in that, The new DBD plasma synthesis device mainly includes components such as a plasma power supply, a reaction tube, a control system for synthesis reaction process technical parameters, a product collection system, and a product analysis system; the plasma power supply includes an inner electrode and an outer electrode. The inner electrode is located on the axis of the reaction tube, and the outer electrode surrounds the outer periphery of the reaction tube; the overlapping area of the inner electrode, outer electrode, and reaction tube is the plasma discharge area; the plasma discharge area is filled with an oxide-based composite catalyst; The reaction tube includes an air inlet and an air outlet; the air inlet is located upstream of the plasma discharge area; the air outlet is located downstream of the plasma discharge area.

3. The method and application for synthesizing acetylene by the synergistic action of DBD plasma and active catalyst according to claim 2, characterized in that, The material of the reaction tube includes quartz, insulating ceramic, corundum, SiC, or metal; the material of the inner electrode is tungsten, iron, and copper; the inner electrode is directly connected to the high-voltage power line; The working mode of the new DBD plasma device is a constant current mode and a constant voltage mode; The input voltage range of the new atmospheric-pressure DBD plasma device is 0V to 250V; it can be increased to more than 7000V after voltage transformation.

4. The method and application for synthesizing acetylene by the synergistic action of DBD plasma and active catalyst according to claims 2 and 3, characterized in that, The outer electrode is aluminum foil or copper foil; the reaction tube is a straight tube, a U-shaped tube, or a spiral ring tube.

5. The method and application for synthesizing acetylene by the synergistic action of DBD plasma and active catalyst according to claim 1, characterized in that, The oxide-based composite catalyst is a composite compound M1O of aluminum oxide, silicon dioxide, magnesium oxide, and zinc oxide x , a manganese oxide-based complex M2O y and a mixture of one or more of titanium dioxide.

6. The method and application for synthesizing acetylene by the synergistic action of DBD plasma and active catalyst according to claim 1, characterized in that, For the method and application of the synergistic synthesis of acetylene by atmospheric-pressure DBD plasma and catalysis, the carbon molar selectivity of acetylene in the synthesis product reaches 47.02%, and the sum of the carbon molar selectivities of the C2 unsaturated hydrocarbons acetylene and ethylene reaches 62.70%.

7. The method and application for synthesizing acetylene by the synergistic action of DBD plasma and active catalyst according to claim 1, characterized in that, For the method and application of the synergistic synthesis of acetylene by atmospheric-pressure DBD plasma and catalysis, the reaction raw material gas is a gas containing methane, and the content of methane is 0.1% to 100%; preferably 2% to 95%, and further preferably 10% to 80%.

8. The method and application for synthesizing acetylene by the synergistic action of DBD plasma and active catalyst according to claim 1, characterized in that, For the method and application of the synergistic synthesis of acetylene by atmospheric-pressure DBD plasma and catalysis, the input voltage range of the new synthesis reaction device is 2V to 220V, preferably 5V to 150V, and further preferably 10V to 100V.

9. The method and application for synthesizing acetylene by the synergistic action of DBD plasma and active catalyst according to claim 1, characterized in that, For the method and application of the synergistic synthesis of acetylene by atmospheric-pressure DBD plasma and catalysis, the reaction raw material gas is a gas containing methane, and in addition to methane, it can also contain one or more of nitrogen, or ethane, or argon, or hydrogen, or ethylene, or carbon dioxide gas, or a small amount of oxygen.

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