An infrared characterization in-situ cell device based on electromagnetic induction technology driven heating and its application in the structural characterization of catalytic materials

Abstract

This invention discloses an in-situ infrared characterization cell device based on electromagnetic induction technology and its application in the structural characterization of catalytic materials. The device includes a reaction tube, an electromagnetic heating system, and an infrared spectrometer. The electromagnetic heating system includes an electromagnetic induction coil, which surrounds the outside of the reaction tube. The infrared sample to be tested is placed in the reaction tube. The device adopts a transmission-type optical path mode, where infrared light emitted by the infrared spectrometer passes through the reaction tube and is collected by an infrared detector on the other side. The electromagnetic induction in-situ infrared reaction cell of this invention can explore the structure and reaction mechanism of materials in an electromagnetic induction environment, filling a technological gap in the field of electromagnetic induction in-situ infrared characterization and possessing strong practicality and promotional value.

Description

Technical Field

[0001] This invention belongs to the field of material structure characterization technology, specifically relating to an in-situ infrared characterization cell device based on electromagnetic induction technology-driven heating and its application in the structural characterization of catalytic materials. Background Technology

[0002] Characterization techniques are crucial for studying the structural characteristics of materials and play a significant role in guiding catalyst development. Among numerous structural characterization techniques, in-situ characterization is considered the most instructive. Through in-situ characterization, we can observe structural changes in materials under reaction or near-reaction conditions, revealing the mechanisms of catalytic reactions. Therefore, the development of in-situ characterization techniques is of great importance to the research of catalytic materials. Among in-situ characterization techniques, in-situ infrared characterization is the most commonly used and representative. Its principle involves introducing a suitable reaction atmosphere into an in-situ reaction tank and providing the catalyst with test conditions close to the reaction environment through heating; then, infrared spectroscopy is used to analyze changes in the reaction atmosphere and catalyst structure. Essentially, current in-situ infrared characterization techniques all achieve controlled heating of the catalyst using traditional heating methods such as resistance furnaces.

[0003] Electromagnetic induction heating is a widely used heating technology. Its working principle is based on inducing eddy currents within ferromagnetic materials using a high-frequency alternating electromagnetic field, thereby causing the material to heat up as a whole. This technology can convert electrical energy into electromagnetic energy and precisely deliver it to the ferromagnetic material, offering advantages such as high energy efficiency and rapid heating rate. Currently, electromagnetic induction heating technology has begun to show promise in research fields such as environmental catalysis. Numerous studies have shown that, compared to traditional heating methods, catalytic materials can achieve higher substrate conversion rates and target product selectivity at lower temperatures under electromagnetic induction. However, the mechanisms by which electromagnetic induction promotes the performance improvement of catalytic materials are still poorly understood, which is closely related to the lack of relevant characterization techniques under current conditions. Summary of the Invention

[0004] To investigate the structural changes of catalysts in an electromagnetic induction environment and the transformation mechanism of reactants on the catalyst, and to fill the technological gap in electromagnetic induction-driven heating in-situ infrared characterization cells, this invention first proposes an in-situ infrared characterization cell device based on electromagnetic induction technology. The device includes a reaction tube, an electromagnetic heating system, and an infrared spectrometer. The electromagnetic heating system includes an electromagnetic induction coil, and the outside of the reaction tube is surrounded by the electromagnetic induction coil. The infrared sample to be tested is placed in the reaction tube. The device adopts a transmission optical path mode, and the infrared light emitted by the infrared spectrometer passes through the reaction tube and is collected by an infrared detector on the other side.

[0005] According to one embodiment of the present invention, the electromagnetic heating system further includes a ZVS electromagnetic generator, a relay, an adjustable DC power supply, and a temperature controller. The electromagnetic induction coil is connected to the ZVS electromagnetic generator, the ZVS electromagnetic generator is connected to the temperature controller via the relay, and the temperature controller is connected to the adjustable DC power supply and directly controls the opening and closing of the relay, thereby intermittently supplying power to the ZVS electromagnetic generator to achieve temperature control.

[0006] According to one embodiment of the present invention, the infrared sample to be tested is placed in the middle of a straight reaction tube in a reaction tube, and the sample section in the reaction tube is placed inside an electromagnetic induction coil, so that the infrared sample to be tested is completely wrapped by the induction coil through the wall of the reaction tube.

[0007] According to one embodiment of the present invention, the reaction tube is made of a non-metallic insulating material, including quartz, glass, alumina ceramic, zirconium oxide ceramic, etc.

[0008] According to one embodiment of the present invention, the left and right ends of the in-situ cell are sealed by infrared transmission windows, and the upper end of the in-situ cell is connected to a two-way tube for introducing and exporting gas, so as to provide a controllable reaction atmosphere environment for the sample.

[0009] According to one embodiment of the present invention, the infrared transmission window is embedded in a threaded connecting sleeve; the threaded connecting sleeve achieves a tight fit with the reaction tube by rotating and compressing the rubber sealing O-ring; a two-way sleeve is welded on the threaded sleeve for gas inlet and outlet; a light shield is also installed on the threaded connecting sleeve to shield the signal from interference by the scattered light of the infrared spectrometer.

[0010] According to one embodiment of the present invention, the infrared sample to be tested is a conventional choice in the art, such as ferromagnetic materials such as nickel foam, iron foam, or iron wool, with iron wool being preferred.

[0011] According to one embodiment of the present invention, the infrared transmission window is a light-transmitting material with low infrared absorption rate, and the selected materials include: calcium fluoride (CaF2), potassium bromide (KBr), zinc selenide (ZnSe), etc.

[0012] According to one embodiment of the present invention, the adjustable DC power supply can provide a DC output voltage of 4V-100V to the ZVS electromagnetic generator, for example, any value among 4V, 8V, 12V, 24V, 32V, and 40V, or any value within a range formed by any two values. Different DC output voltages can drive the ZVS electromagnetic generator to produce high-frequency alternating current of different intensities, thereby generating an alternating magnetic field of 8mT-100mT.

[0013] According to one embodiment of the present invention, the relay can be either DC-DC or AC-DC depending on the control mode of the temperature controller. By opening / closing the relay, the connection between the DC power supply and the ZVS electromagnetic generator is controlled, thereby completing the automatic switching operation of the electromagnetic induction generation module.

[0014] According to one embodiment of the present invention, the temperature of the infrared sample to be tested is detected by a thermocouple or an infrared probe, and the detected temperature range is 0 – 1000 °C. o C. The detected temperature is fed back to the temperature controller in real time, and the temperature controller then issues a command to control the opening and closing of the relay, thereby realizing the controllable heating of the infrared sample to be tested.

[0015] According to one embodiment of the present invention, the thermocouple is a type K or type E thermocouple.

[0016] According to one embodiment of the present invention, in order to ensure that the reaction tube has sufficient pressure resistance, the wall thickness of the reaction tube is not less than 1 mm; in order to avoid the mutual influence of temperature between the electromagnetic induction coil and the reaction tube, the distance (LR) between the outer diameter (R) of the reaction tube and the radius (L) of the electromagnetic induction coil is not less than 5 mm, for example, 0.5-1 cm.

[0017] According to another aspect of the present invention, the present invention also provides the application of the above-described in-situ infrared characterization reaction cell in the structural characterization of catalytic materials, characterized in that,

[0018] S1: Place the infrared sample to be tested in the reaction tube of the in-situ cell, connect the reaction gas connecting tubes at both ends and insert thermocouples to ensure good contact between the thermocouples and the infrared sample bed.

[0019] S2: Place the entire reaction tube in the center of the copper coil, set the preset DC power supply voltage and heating rate, start heating, and the temperature of the infrared sample to be tested will gradually increase according to the preset temperature.

[0020] S3: Introduce the reaction gas and use an infrared spectrometer to detect and record the atmospheric changes during the reaction process. The detection results are the structural characterization of the catalytic material.

[0021] In this invention, the infrared sample to be tested is the catalytic material.

[0022] According to one embodiment of the present invention, the catalyst material in step S1 can be a ferromagnetic catalyst material such as nickel foam, iron foam, or metallic iron wool.

[0023] According to one embodiment of the present invention, in step S2, the voltage of the DC power supply is 12-48 V, and the preset heating rate is 5-100. o C / min.

[0024] The beneficial effects of this invention are:

[0025] The electromagnetic induction in-situ infrared reaction cell of this invention can be used to explore the structure and reaction mechanism of materials in an electromagnetic induction environment, filling the technical gap in the field of electromagnetic induction in-situ infrared characterization, and has strong practicality and promotion value. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the electromagnetic induction in-situ infrared cell device of the present invention.

[0027] Figure 2 This shows the relative positions of the reaction tube and the induction coil in the electromagnetic induction in-situ infrared cell of this invention.

[0028] Figure 3 This is an explanatory diagram of the connection part of the electromagnetic induction in-situ infrared cell of the present invention.

[0029] Figure 4 This is a diagram showing the detection results of Embodiment 1 of the present invention.

[0030] Figure 5 This is a diagram showing the detection results of Embodiment 2 of the present invention. Detailed Implementation

[0031] The design principles of the device of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0032] Example 1

[0033] like Figure 1 As shown, an in-situ infrared characterization reaction cell device based on electromagnetic induction technology-driven heating is disclosed. The device includes a reaction tube, an electromagnetic heating system, and an infrared spectrometer. The electromagnetic heating system includes an electromagnetic induction coil. The outer side of the reaction tube is surrounded by the electromagnetic induction coil. The infrared sample to be tested is placed in the middle of the straight reaction tube. The device adopts a transmission optical path mode. The infrared light emitted by the infrared spectrometer passes through the reaction tube and is collected by an infrared detector on the other side.

[0034] The electromagnetic heating system also includes a ZVS electromagnetic generator, a relay, an adjustable DC power supply, and a temperature controller. The electromagnetic induction coil is connected to the ZVS electromagnetic generator, which is connected to the temperature controller via the relay. The temperature controller is connected to the adjustable DC power supply and directly controls the opening and closing of the relay, thereby providing intermittent power to the ZVS electromagnetic generator to control the temperature.

[0035] The in-situ pool is located at both ends through infrared transmission windows (i.e. Figure 1 The in-situ cell is sealed with a mid-infrared window and a two-way tube is connected to the upper end for introducing and exporting gas, providing a controllable reaction atmosphere environment for the sample.

[0036] The infrared transmission window is embedded in a threaded connecting sleeve; the threaded connecting sleeve is tightly fitted to the reaction tube by rotating and compressing the rubber sealing O-ring; a two-way sleeve is welded to the threaded sleeve for gas inlet and outlet; a light-shielding plate (i.e., Figure 1 A light-blocking plate is used to shield the infrared spectrometer from interference with the signal caused by scattered light.

[0037] The temperature of the infrared sample to be tested is detected by a thermocouple. The distance (LR) between the outer diameter (R) of the reaction tube and the radius (L) of the electromagnetic induction coil is 0.5 – 1 cm.

[0038] Using metallic iron wool as a ferromagnetic catalyst, i.e., the infrared sample to be tested, and with Figure 1 Taking the reaction apparatus as an example, 50 mg of iron wool is placed inside the reaction tube of the in-situ cell. Gas connecting pipes are connected to both ends, and thermocouples are inserted to ensure good contact between the thermocouples and the catalyst bed (i.e., the infrared sample). The entire reaction tube is placed in the center of the copper coil. The DC power supply voltage is set to 24 V, and the heating rate is set to 10. o C / min. Heating is initiated, with an instantaneous magnetic field strength of 24 mT at the center of the coil. The catalyst temperature gradually increases according to the preset temperature. Reaction gas is introduced, and atmospheric changes are detected using an infrared spectrometer.

[0039] When a 10% CO2 / 40% H2 / Ar mixture is introduced, and the temperature of the reaction bed is controlled at 450°C via electromagnetic induction... o C. Use an infrared analyzer to record the changes in the infrared characteristics of the gas in the reaction cell. For example... Figure 4 As shown, under the driving force of electromagnetic induction, CO2 is significantly consumed, and its characteristic negative peak is significantly enhanced over time, accompanied by changes in the characteristic peaks of CO and formic acid intermediates.

[0040] Example 2

[0041] Using nickel foam as a ferromagnetic catalyst, and with Figure 1 Taking the reaction apparatus in the example, nickel foam is placed inside the reaction tube of the in-situ cell. Gas connecting pipes are connected to both ends, and thermocouples are inserted to ensure good contact between the thermocouples and the catalyst bed. The entire reaction tube is placed in the center of a copper coil. The DC power supply voltage is set to 24V, and the heating rate is set to 10. oC / min. Heating is initiated, with the instantaneous magnetic field strength at the center of the coil reaching 24 mT. The catalyst temperature gradually increases according to the preset temperature. Reaction gas is introduced, and atmospheric changes are detected using an infrared spectrometer.

[0042] When a toluene-air mixture of 1000 ppm is introduced, and the temperature of the reaction bed is controlled at 200°C via electromagnetic induction... o C. Use an infrared analyzer to record the changes in the infrared characteristics of the gas in the reaction cell. For example... Figure 5 As shown, under the driving force of electromagnetic induction, obvious characteristic infrared absorption changes of the toluene reaction intermediate can be observed.

[0043] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An in-situ infrared characterization cell device with electromagnetic induction-driven heating, characterized in that... The device includes a reaction tube, an electromagnetic heating system, and an infrared spectrometer. The electromagnetic heating system includes an electromagnetic induction coil. The outside of the reaction tube is surrounded by the electromagnetic induction coil. The infrared sample to be tested is placed in the reaction tube. The device adopts a transmission optical path mode. The infrared light emitted by the infrared spectrometer passes through the reaction tube and is collected by an infrared detector on the other side. The electromagnetic heating system also includes a ZVS electromagnetic generator, a relay, an adjustable DC power supply, and a temperature controller. The electromagnetic induction coil is connected to the ZVS electromagnetic generator, the ZVS electromagnetic generator is connected to the temperature controller through the relay, and the temperature controller is connected to the adjustable DC power supply and directly controls the opening and closing of the relay. The in-situ cell is sealed at both ends by infrared transmission windows, and a two-way tube is connected to the upper end of the in-situ cell for introducing and exporting gas, providing a controllable reaction atmosphere environment for the sample. The infrared transmission window is embedded in a threaded connecting sleeve; the threaded connecting sleeve achieves a tight fit with the reaction tube by rotating and compressing the rubber sealing O-ring; a two-way sleeve is welded on the threaded sleeve for gas inlet and outlet; a light shield is also installed on the threaded connecting sleeve.

2. The apparatus according to claim 1, characterized in that, The reaction tube is made of a non-metallic insulating material, including quartz, glass, alumina ceramic, or zirconium oxide ceramic.

3. The apparatus according to claim 1, characterized in that, The infrared transmission window is made of a light-transmitting material with low infrared absorption rate, and the selected materials include calcium fluoride, potassium bromide, and zinc selenide.

4. The apparatus according to claim 1, characterized in that, The adjustable DC power supply provides the ZVS electromagnetic generator with a DC output voltage of 4 V-100 V.

5. The apparatus according to claim 1, characterized in that, The distance between the outer diameter R of the reaction tube and the radius L of the electromagnetic induction coil is not less than 5 mm.

6. The application of the device as described in any one of claims 1-5 in the structural characterization of catalytic materials, characterized in that, Includes the following steps: S1: Place the infrared sample to be tested in the reaction tube of the in-situ cell, connect the reaction gas connecting tubes at both ends and insert thermocouples to ensure good contact between the thermocouples and the infrared sample bed. S2: Place the entire reaction tube in the center of the copper coil, set the preset DC power supply voltage and heating rate, start heating, and the temperature of the infrared sample to be tested will gradually increase according to the preset temperature. S3: Introduce the reaction gas and use an infrared spectrometer to detect and record the atmospheric changes during the reaction process. The detection results are the structural characterization of the catalytic material.

7. In the application according to claim 6, the catalytic material in step S1 is nickel foam, iron foam, or ferromagnetic catalytic material made of metallic iron wool; In step S2, the DC power supply voltage is 12-48 V, and the preset heating rate is 5-100°C. o C / min.

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