Multifunctional in-situ DRIFTS reactor

Abstract

The utility model discloses a multifunctional in-situ DRIFTS reactor which comprises a reaction shell provided with a reaction cavity as well as a gas inlet and a gas outlet which are communicated with the reaction cavity; the catalyst fixing device is arranged in the reaction cavity and is filled with a catalyst; the electrode assembly is arranged in the reaction cavity, connected with an external power supply and used for generating plasma; the equipment connecting assembly is arranged on the surface of the reaction shell and provided with a limiting hole and a limiting column which are connected with an external DRIFTS spectrometer, perfect combination of the plasma environment and in-situ DRIFTS analysis is achieved, and a powerful experimental platform is provided for CO2 resource utilization research.

Description

Technical Field

[0001] The utility model relates to the technical fields of catalytic chemistry and spectral analysis, and particularly relates to a multifunctional in-situ DRIFTS reactor. Background Art

[0002] The catalytic hydrogenation conversion of carbon dioxide is an important way to address climate change and develop renewable energy. Traditional thermal catalytic methods face problems such as high energy consumption and low conversion efficiency. In recent years, plasma-assisted catalytic technology has received extensive attention because it can activate CO2 molecules at low temperatures. However, the current design of plasma catalytic reactors still has the following problems:

[0003] (1) The synergistic mechanism between plasma and catalyst is not clear, and there is a lack of effective in-situ characterization means; reaction conditions (such as temperature, pressure, electric field strength, etc.) are difficult to precisely control and quickly adjust;

[0004] (2) The catalyst is prone to deactivation or loss under the action of strong electric fields and plasma; the energy utilization efficiency is low, and the CO2 conversion rate and the selectivity of target products need to be improved;

[0005] (3) The reactor structure is fixed, making it difficult to adapt to different types of catalysts and reaction conditions; existing in-situ DRIFTS analysis devices are difficult to effectively integrate with plasma reactors.

[0006] In the prior art, some scholars have proposed various improvement measures, such as using different discharge modes such as dielectric barrier discharge (DBD) and microwave discharge, or combining in-situ spectral analysis technology. However, these solutions often only solve some problems and lack systematicness and multifunctionality. Especially in the integration of plasma reactions and in-situ DRIFTS analysis, many challenges still remain. Therefore, it is of great practical significance to develop a plasma catalytic reactor that integrates multiple functions, has strong applicability, and can achieve high-quality in-situ DRIFTS analysis. Summary of the Utility Model

[0007] To solve the above technical problems, the utility model provides a multifunctional in-situ DRIFTS reactor, which realizes the perfect combination of the plasma environment and in-situ DRIFTS analysis, and provides a powerful experimental platform for the research on the resource utilization of CO2.

[0008] The utility model adopts the following technical solutions:

[0009] A multifunctional in-situ DRIFTS reactor, comprising:

[0010] A reaction housing having a reaction chamber, a gas inlet communicating with the reaction chamber, and a gas outlet;

[0011] A catalyst fixing device is arranged in a reaction chamber and is filled with a catalyst;

[0012] An electrode assembly is arranged in the reaction chamber, is connected to an external power supply, and is used for generating plasma;

[0013] A device connection assembly is arranged on the surface of the reaction shell and has a limit hole and a limit post for connecting to an external DRIFTS spectrometer.

[0014] Preferably, the reaction shell includes a dome and a base, and the dome and the base are covered to form a reaction chamber.

[0015] Preferably, a gas mixing chamber and a confluence part at the rear end of the gas mixing chamber are arranged on the base.

[0016] Preferably, the gas mixing chamber is located inside the base and is connected to a gas inlet, and the gas mixing chamber is a cuboid cavity.

[0017] Preferably, a product collection assembly is arranged below the catalyst fixing device, and the product collection assembly includes a gas output channel.

[0018] Preferably, the electrode assembly includes a detachable electrode head and an electrode support rod. The material of the electrode head is platinum, tungsten or stainless steel. The diameter of the electrode head is 1-5 mm, and the length of the electrode head is 50-200 mm.

[0019] Preferably, the catalyst fixing device is a porous ceramic or a metal mesh. The pore diameter of the porous ceramic or the metal mesh is 5-50 μm, and the thickness is 1-5 mm.

[0020] Preferably, the porous ceramic or the metal mesh has microchannels, and the catalyst can be fixed in the microchannels.

[0021] Preferably, the catalyst fixing device includes a metal mesh and a ceramic membrane, and the catalyst is located between the metal mesh and the ceramic membrane.

[0022] Preferably, an in-situ DRIFTS analysis interface is arranged on the dome, and the in-situ DRIFTS analysis interface is a zinc selenide lens window.

[0023] Preferably, the electrode assembly includes a plurality of needle-shaped electrodes uniformly distributed, and the diameter of each needle-shaped electrode is 0.5-1.5 mm.

[0024] Compared with the prior art, the present utility model has the following advantages:

[0025] 1. The present utility model provides a multi-functional in-situ DRIFTS reactor, which integrates functions such as plasma generation, catalytic reaction, temperature regulation, and in-situ DRIFTS analysis, achieving a perfect combination of the plasma environment and in-situ DRIFTS analysis, and providing a powerful experimental platform for the research on the resource utilization of CO2.

[0026] 2. Flexible adaptability: The modular design allows components to be replaced according to different experimental requirements; for example, structures such as electrode heads and metal meshes with different lengths and sizes can be replaced.

[0027] 3. Precise control: Precise control and rapid adjustment of reaction conditions are achieved; conditions such as gas ratio, electrode spacing, voltage intensity, and environmental temperature can be adjusted.

[0028] 4. In-situ characterization: The DRIFTS analysis interface facilitates in-depth study of the reaction mechanism; the species changes on the catalyst surface during the reaction process are monitored in real time through the zinc selenide lens window.

[0029] 5. Catalyst protection: Special fixing devices prevent the loss of catalysts under strong electric fields; the three-layer structure of "metal mesh - catalyst - ceramic membrane" or microchannels on carriers such as metal meshes prevent the loss of catalysts.

[0030] 6. Energy efficiency improvement: The optimized gas distribution system improves the contact efficiency between reactants and catalysts. Description of the Drawings

[0031] Figure 1 It is a schematic structural diagram of the multi-functional in-situ DRIFTS reactor in the open state.

[0032] Figure 2 It is a cross-sectional view of the multi-functional in-situ DRIFTS reactor.

[0033] Figure 3 It is a schematic structural diagram of the multi-functional in-situ DRIFTS reactor.

[0034] Figure 4 It is a partial cross-sectional view of the multi-functional in-situ DRIFTS reactor.

[0035] Figure 5 It is another partial cross-sectional view of the multi-functional in-situ DRIFTS reactor.

[0036] In the figure, reaction housing 1, reaction chamber 1-1, gas inlet 1-2, gas outlet 1-3, dome 1-4, base 1-5, gas mixing chamber 1-6, confluence part 1-7, catalyst fixing device 2, electrode assembly 3, equipment connection assembly 4, limit hole 4-1, limit post 4-2, product collection assembly 5, in-situ DRIFTS analysis interface 6. Detailed Embodiment

[0037] To facilitate the understanding of the technical solution of the present utility model, the following provides a detailed description in conjunction with the accompanying drawings and specific embodiments.

[0038] As Figures 1-5 shown, a multifunctional in-situ DRIFTS reactor includes a reaction housing 1, a catalyst fixing device 2, an electrode assembly 3, and an equipment connection assembly 4;

[0039] The reaction housing 1 has a reaction chamber 1-1, a gas inlet 1-2 communicating with the reaction chamber 1-1, and a gas outlet 1-3, ensuring that the reaction gas enters the reaction chamber 1-1 evenly;

[0040] The catalyst fixing device 2 is arranged in the reaction chamber 1-1 and is filled with a catalyst;

[0041] The electrode assembly 3 is arranged in the reaction chamber 1-1 and is connected to an external power supply for generating plasma;

[0042] The equipment connection assembly 4 is arranged on the surface of the reaction housing 1 and has a limit hole 4-1 and a limit post 4-2 connected to an external DRIFTS spectrometer;

[0043] Integrating functions such as plasma generation, catalytic reaction, and in-situ DRIFTS analysis, it realizes the perfect combination of the plasma environment and in-situ DRIFTS analysis, providing a powerful experimental platform for the research on the resource utilization of CO2.

[0044] Among them, the reaction housing 1 includes a dome 1-4 and a base 1-5. The dome 1-4 and the base 1-5 are detachably connected by bolts. The dome 1-4 and the base 1-5 cover to form the reaction chamber 1-1. The reaction chamber 1-1, as the core of the entire reaction system, provides a basis for the installation and fixation of other components.

[0045] The electrode assembly 3 includes a high-voltage electrode 3-1 and a ground electrode. One end of the high-voltage electrode 3-1 is embedded in the catalyst and is connected to an external power supply for generating plasma. The dome 1-4 is supported by a conductive material and serves as the ground electrode in this embodiment.

[0046] As Figure 2 shown, the base 1-5 is provided with a gas mixing chamber 1-6 and a confluence part 1-7 at the rear end of the gas mixing chamber 1-6. The gas mixing chamber 1-6 is located inside the base 1-5 and is connected to the gas inlet 1-2.

[0047] A product collection assembly 5 is provided below the catalyst fixing device 2. The product collection assembly 5 includes a gas output channel, which belongs to the gas output part of the reactor and is used for collecting and outputting reaction products.

[0048] The electrode assembly 3 includes a detachable electrode head and an electrode support rod. The material of the electrode head is platinum, tungsten or stainless steel. The diameter of the electrode head is 1-5 mm, and the length of the electrode head is 50-200 mm, which can adapt to different discharge modes, such as dielectric barrier discharge, microwave discharge, etc.; The electrode support rod consists of two parts, a two-way joint and a nut, which are jointly used for the limit and fixation of the electrode head.

[0049] An in-situ DRIFTS analysis interface 6 is provided on the dome 1-4. The in-situ DRIFTS analysis interface 6 is a zinc selenide lens window. The diameter of the zinc selenide lens window is 10-30 mm, which is compatible with the DRIFTS spectrometer to monitor the species change on the catalyst surface during the reaction in real time.

[0050] During use, the test gas enters the reaction chamber 1-1 through the gas inlet 1-2 according to a preset ratio. The electrode assembly 3 generates plasma to activate the entering gas molecules. The activated gas molecules react with the catalyst fixed on the catalyst fixing device 2. The species change on the catalyst surface during the reaction is monitored in real time through the in-situ DRIFTS analysis interface 6. The reaction products are collected by the confluence part 1-7 and output through the product collection assembly 5. Based on the collected spectral and product data, the reaction conditions are continuously optimized.

[0051] As an implementation manner, the inner wall of the reaction chamber 1-1 is made of high-temperature resistant and corrosion-resistant quartz glass or ceramic material, with an inner diameter of 40-120 mm and a height of 60-250 mm.

[0052] As an implementation manner, the catalyst fixing device 2 is a porous ceramic or a metal mesh. The pore diameter of the porous ceramic or metal mesh is 5-50 μm, and the thickness is 1-5 mm, ensuring the uniform distribution of the catalyst and preventing the catalyst from flying away under a strong electric field.

[0053] As a preferred manner, the porous ceramic or metal mesh has microchannels, and the catalyst can be fixed in the microchannels. The width of the microchannels is 100-500 μm, and the depth is 100-300 μm. It not only increases the specific surface area but also prevents the loss of the catalyst.

[0054] As a preferred manner, the catalyst fixing device 2 includes a metal mesh and a ceramic membrane. The catalyst is located between the metal mesh and the ceramic membrane, and the "metal mesh - catalyst - ceramic membrane" three-layer structure is used to prevent the loss of the catalyst.

[0055] As a preferred manner, a catalyst carrier with a complex pore structure is fabricated by 3D printing technology, which can achieve the high dispersion and fixation of the catalyst.

[0056] Expansion of in-situ analysis techniques: To obtain more comprehensive reaction information, the following in-situ analysis techniques can be added: 1) In-situ XRD: Open a large-area Be window on the reactor wall and cooperate with a synchrotron radiation source to achieve real-time dynamic analysis of the catalyst structure. 2) In-situ electron paramagnetic resonance (EPR): Through a specially designed resonator cavity, study the generation and evolution process of free radicals in the plasma. 3) Optical emission spectroscopy (OES): Install an optical fiber probe on the reactor to monitor the active species in the plasma in real time.

[0057] The electrode assembly 3 includes a number of evenly distributed needle-shaped electrodes, and the diameter of each needle-shaped electrode is 0.5 - 1.5 mm.

[0058] Example 1: Hydrogenation of CO2 to CH4.

[0059] The reaction chamber 1-1 is made of quartz glass, with an inner diameter of 60 mm and a height of 150 mm. The electrode assembly 3 includes replaceable needle-shaped platinum electrodes (diameter 2 mm) and stainless steel support rods. The catalyst fixing device 2 uses porous α-Al2O3 ceramics (pore diameter 20 μm, thickness 3 mm) to fix the 10 wt% Ni / CeO2 catalyst. The base 1-5 is provided with 16 evenly distributed intake small holes (diameter 1 mm). The in-situ DRIFTS analysis interface 6 includes 4 specially designed quartz windows (diameter 20 mm) and 2 gas sampling ports. During operation, CO2 and H2 are introduced into the reactor at a ratio of 1:4, and the total flow rate is 200 mL / min. The electrode spacing is adjusted to 10 mm, and an AC voltage of 20 kV is applied with a frequency of 10 kHz. The reaction temperature is controlled at 300 °C. The change of surface species during the reaction process is monitored in real time by in-situ DRIFTS spectroscopy, and at the same time, the product composition is analyzed by on-line gas chromatography. Under the above conditions, after the reactor operates stably for 10 hours, the conversion rate of CO2 reaches 75%, and the selectivity of CH4 is 85%. The in-situ DRIFTS spectrum shows that under the action of the plasma, a large number of active intermediates, such as CO2- and HCOO- species, are formed on the catalyst surface, and the concentration of these intermediates is about 3 times higher than that under traditional thermal catalytic conditions. This result confirms the unique advantage of the plasma in activating CO2 molecules.

[0060] Example 2: Hydrogenation of CO2 to CO.

[0061] The reaction chamber is made of alumina ceramic, with an inner diameter of 100 mm and a height of 200 mm. The electrode assembly 3 includes a replaceable flat electrode (diameter 30 mm, thickness 2 mm), made of platinum-plated titanium mesh. The catalyst fixing device 2 uses a stainless steel wire mesh (pore diameter 30 μm, thickness 2 mm) to fix the 5 wt% Cu-ZnO / Al2O3 catalyst. The base 1-5 includes a spiral gas channel to ensure uniform gas distribution. The in-situ DRIFTS analysis interface 6 is added with a window for Raman spectroscopy. Operating conditions: CO2 and H2 are introduced into the reactor in a ratio of 1:1, with a total flow rate of 500 mL / min. The electrode spacing is set at 15 mm, an AC voltage of 15 kV is applied, and the frequency is 15 kHz. The reaction temperature is controlled at 250 °C. The in-situ DRIFTS spectrum is used to monitor the structural changes on the catalyst surface, and at the same time, the product composition is analyzed in real time using mass spectrometry. Under these conditions, the reactor operates continuously for 24 hours, and the conversion rate of CO2 is stable at about 70%, and the selectivity of CO is as high as 95%. The results of the in-situ DRIFTS spectrum show that the plasma significantly promotes the formation of Cu+ species, which is considered to be the active center for the reaction of CO2 hydrogenation to CO. Compared with traditional thermal catalysis, the CO2 conversion rate of this reactor at the same temperature is increased by about 40%, and the energy consumption is reduced by 30%.

[0062] The above are only the preferred embodiments of the present invention. The protection scope of the present invention shall be subject to the scope defined by the claims. Several improvements and refinements made by those skilled in the art without departing from the spirit and scope of the present invention shall also be regarded as within the protection scope of the present invention.

Claims

1. A multifunctional in-situ DRIFTS reactor, characterized in that: include: A reaction housing (1) having a reaction chamber (1-1) and a gas inlet (1-2) and a gas outlet (1-3) connected to the reaction chamber (1-1); A catalyst fixing device (2) is arranged in the reaction chamber (1-1) and is loaded with a catalyst; An electrode assembly (3) is arranged in the reaction chamber (1-1) and connected to an external power source for generating plasma; and an equipment connection assembly (4) is arranged on the surface of the reaction shell (1) and has a limiting hole (4-1) and a limiting column (4-2) connected to an external DRIFTS spectrometer.

2. The multifunctional in-situ DRIFTS reactor according to claim 1, characterized in that: The reaction housing (1) comprises a dome (1-4) and a base (1-5); the dome (1-4) and the base (1-5) are covered together to form a reaction chamber (1-1).

3. The multifunctional in-situ DRIFTS reactor according to claim 2, characterized in that: The base (1-5) is provided with a gas mixing chamber (1-6) and a confluence portion (1-7) at the rear end of the gas mixing chamber (1-6).

4. The multifunctional in-situ DRIFTS reactor according to claim 1, characterized in that: A product collecting assembly (5) is provided below the catalyst fixing device (2), and the product collecting assembly (5) comprises a gas output channel.

5. The multifunctional in-situ DRIFTS reactor according to claim 1, characterized in that: The electrode assembly (3) comprises a detachable electrode head and an electrode support rod. The electrode head is made of platinum, tungsten or stainless steel. The diameter of the electrode head is 1-5 mm and the length of the electrode head is 50-200 mm.

6. The multifunctional in-situ DRIFTS reactor according to claim 1, characterized in that: The catalyst fixing device (2) is a porous ceramic or metal mesh, the pore size of the porous ceramic or metal mesh is 5-50 μm, and the thickness is 1-5 mm.

7. The multifunctional in-situ DRIFTS reactor according to claim 6, characterized in that: The porous ceramic or metal mesh has microchannels, and the catalyst can be fixed in the microchannels.

8. The multifunctional in-situ DRIFTS reactor according to claim 1, characterized in that: The catalyst fixing device (2) comprises a metal mesh and a ceramic membrane, and the catalyst is located between the metal mesh and the ceramic membrane.

9. The multifunctional in-situ DRIFTS reactor according to claim 2, characterized in that: The dome (1-4) is provided with an in-situ DRIFTS analysis interface (6), and the in-situ DRIFTS analysis interface (6) is a zinc selenide lens window.

10. The multifunctional in-situ DRIFTS reactor according to claim 1, characterized in that: The electrode assembly (3) comprises a plurality of evenly distributed needle-shaped electrodes, each of which has a diameter of 0.5-1.5 mm.

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