A reactor applied to micro fluidized bed thermal gravimetric analysis and thermal gravimetric analysis device

Abstract

The application provides a reactor applied to micro fluidized bed thermal gravimetric analysis and a thermal gravimetric analysis device, which comprises, from bottom to top, a connecting pipe section, a heating pipe section and a reaction pipe section connected in sequence; the lower end of the connecting pipe section is used for being connected with a gas source, and a wind distribution plate is arranged at the connecting position of the connecting pipe section and the heating pipe section; the inner wall of the heating pipe section is in a sine wave structure; a heat conduction plate is arranged in the heating pipe section, and the heat conduction plate is located at a preset position above the wind distribution plate; the upper end of the reaction pipe section is provided with a top cover, and a central through hole is arranged in the top cover; the inner wall of the heating pipe section is arranged in a sine wave structure, the inner wall structure in a sine wave is utilized, the heating area of the fluidized medium is effectively increased, and the heat transfer efficiency is greatly enhanced; the heat conduction plate is additionally arranged in the heating pipe section, the heat conduction performance of the heat conduction plate is utilized, the heat transfer efficiency is improved, the uniformity of temperature distribution in the reactor is promoted, the heating rate of the fluidized medium is further improved, and the accuracy of test results is ensured.

Description

Technical Field

[0001] This invention belongs to the field of thermogravimetric analysis technology, and specifically relates to a reactor and thermogravimetric analysis device for use in micro fluidized bed thermogravimetric analysis. Background Technology

[0002] The Fluidized Bed Thermo-Gravimetric Analyzer (MFB-TGA) system is a novel instrument for measuring chemical reaction kinetic parameters, developed by combining the measurement principles of thermogravimetric analysis with the efficient mass and heat transfer characteristics of fluidized beds. It overcomes the problems inherent in both micro-fluidized bed reaction analyzers and thermogravimetric analyzers. The MFB-TGA system inherits the advantages of both fluidized beds and thermogravimetric analysis, enabling real-time and accurate acquisition of mass change data during the reaction process of fluidized particles. It can obtain the reaction kinetic characteristics of fluidized particles under different experimental conditions. Simultaneously, it can measure the changes in the concentration of gaseous components, thereby obtaining the reaction kinetic characteristics of the gaseous components. Finally, by comparing and analyzing the kinetic parameters of gaseous components and solid particles, reaction kinetic equations that are closer to those used in actual industrial applications are obtained, leading to the gradual application of the micro-fluidized bed thermogravimetric analysis system in gas-solid reaction research across various fields.

[0003] Currently, in existing micro-fluidized bed (MFB) reactors, the heating rate of the fluidized medium near the fluidized bed wall is higher than that inside the fluidized bed; the lower bed height results in a shorter gas phase residence time, which easily leads to interphase temperature differences; at the same time, the carrier gas velocity can easily affect thermogravimetric mass monitoring. Summary of the Invention

[0004] To address the technical problems existing in the prior art, the present invention provides a reactor and thermogravimetric analysis device for micro fluidized bed thermogravimetric analysis, so as to solve the problems that the interphase temperature difference is easily generated in the existing fluidized bed reactor and the carrier gas velocity is easily affected by thermogravimetric quality monitoring.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] The present invention provides a reactor for thermogravimetric analysis in a micro fluidized bed, comprising a connecting pipe section, a heating pipe section and a reaction pipe section connected sequentially from bottom to top;

[0007] The lower end of the connecting pipe section is used to connect to the air source, and an air distribution plate is provided at the connection between the connecting pipe section and the heating pipe section; the inner wall of the heating pipe section has a sinusoidal waveform structure; a heat-conducting plate is provided in the heating pipe section, and the heat-conducting plate is located at a preset position above the air distribution plate;

[0008] The upper end of the reaction tube section is provided with a top cover, and the top cover is provided with a central through hole; wherein, the lower end of the central through hole is connected to the inner cavity of the reaction tube section, and the upper end of the central through hole is connected to the top surface of the top cover.

[0009] Furthermore, the heat-conducting plate is a curved panel structure with a preset thermal conductivity.

[0010] Furthermore, the reaction tube section includes a constant-diameter reaction section and a gradually expanding buffer section; the lower port of the constant-diameter reaction section is connected to the upper port of the heating tube section, the upper port of the constant-diameter reaction section is connected to the lower port of the gradually expanding buffer section, and the upper port of the gradually expanding buffer section is sealed to the lower end of the top cover.

[0011] Furthermore, it also includes a heating device and a thermocouple; the heating device is located on the outside of the heating tube section; the top cover is provided with a thermocouple insertion port, through which the thermocouple is inserted into the inner cavity area of ​​the heating tube section.

[0012] The present invention also provides a thermogravimetric analysis apparatus, including a fluidized bed reactor, a buffer chamber, a weighing device, an inlet pipe, and an outlet pipe;

[0013] The fluidized bed reactor is a type of reactor used for micro fluidized bed thermogravimetric analysis; the buffer gas chamber is fixedly installed above the weighing device; the weighing device is used to monitor the mass of the fluidized bed reactor and the buffer gas chamber in real time.

[0014] A carrier gas inlet is provided on one side of the buffer gas chamber, and the carrier gas inlet is connected to a gas source through the air inlet pipe; a pressure tap is provided on the other side of the buffer gas chamber, and a pressure monitoring device is provided at the pressure tap.

[0015] The buffer gas chamber is provided with a carrier gas outlet at its top; the fluidized bed reactor is located above the buffer gas chamber, and the lower port of the connecting pipe section in the fluidized bed reactor is connected to the carrier gas outlet.

[0016] One end of the outlet pipe is connected to the upper end of the central through hole in the fluidized bed reactor, and the other end of the outlet pipe is used to connect to a gas chromatograph or a mass spectrometer.

[0017] Furthermore, the air pressure monitoring device employs a differential pressure sensor, and the differential pressure sensor is connected to the pressure tapping port via a first flexible hose.

[0018] Furthermore, the carrier gas inlet is connected to the air inlet pipe by a second flexible hose, and the air outlet pipe is connected to the upper end of the central through hole by a third flexible hose.

[0019] Furthermore, the gas source is an air source or a gas storage cylinder containing carrier gas.

[0020] Furthermore, when the gas source is an air source, a plasma synthesis jet generator is provided between the air inlet pipe and the air source, and a first one-way valve is provided at the inlet end of the plasma synthesis jet generator, and a second one-way valve is provided at the outlet end of the plasma synthesis jet generator.

[0021] Furthermore, when the gas source is a gas storage cylinder containing carrier gas, a flow controller is provided between the air inlet pipe and the gas storage cylinder containing carrier gas; wherein, the flow controller is used to control the flow rate of carrier gas in the air inlet pipe.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] This invention provides a reactor and thermogravimetric analysis device for micro fluidized bed thermogravimetric analysis. The inner wall of the heating tube section is designed with a sinusoidal waveform structure, which, by mimicking the sinusoidal waveform of a squid fin, effectively increases the heating area of ​​the fluidizing medium and greatly enhances the heat transfer efficiency. At the same time, by adding a heat-conducting plate in the heating tube section, the heat transfer efficiency is significantly improved by utilizing the heat-conducting properties of the plate, while also promoting the uniformity of temperature distribution within the reactor. This, in turn, increases the heating rate of the fluidizing medium and ensures the accuracy of the experimental results.

[0024] Furthermore, the heat-conducting plate is designed as a curved panel structure, which increases the contact area between the heat-conducting plate and the fluidizing medium, effectively improving the heat transfer efficiency of the heat-conducting plate.

[0025] Furthermore, the reaction tube section is designed as a combination of a reaction section of equal diameter and a gradually expanding buffer section connected in sequence, so that the carrier gas has a large flow cross section, so that the gas flows smoothly in the reactor, thereby ensuring the stability of the carrier gas and the tail gas, and finally obtaining a smooth measurement curve. At the same time, in the gradually expanding buffer section, the particles carried by the fluidization can be separated from the gas, reducing the entrainment of particles in the tail gas, and thus reducing measurement disturbance.

[0026] Furthermore, by setting up thermocouples and inserting them into the inner cavity of the heating tube section, real-time monitoring of the fluidized medium temperature was achieved, ensuring the accuracy and scientific validity of the test results.

[0027] Furthermore, by setting up a buffer chamber in the thermogravimetric analysis device, the carrier gas is buffered, effectively reducing pressure pulsation in the gas supply system. At the same time, by placing the pressure tap on the side wall of the buffer chamber, the influence of the carrier gas velocity on the thermogravimetric mass detection is avoided, effectively improving the accuracy of the test results.

[0028] Furthermore, a first flexible hose is used to connect the air pressure monitoring device to the pressure tap, a second flexible hose is used to connect the carrier gas inlet to the air inlet pipe, and a third flexible hose is used to connect the air outlet pipe to the central through hole. This ensures that the weighing device can accurately weigh the reactor and guarantees the accuracy of the mass data. At the same time, it facilitates the disassembly of the device to add fluidizing medium into the reactor, which greatly improves the efficiency of the experiment.

[0029] Furthermore, to enhance the fluidization effect, when fluidizing in an air atmosphere, the plasma synthesis jet generator has significant advantages in size and weight, which can conveniently provide gas power for the fluidized bed; at the same time, it further improves the fluidization effect; secondly, the plasma synthesis jet generator used is a dry, oil-free device, which does not require lubricating oil, avoids contamination of the working medium, and will not interfere with the analysis of the medium. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the reactor used for thermogravimetric analysis in a micro fluidized bed as described in Example 1;

[0031] Figure 2 The diagram shows the temperature distribution curves inside the reactor in Example 1 and the conventional reactor.

[0032] Figure 3 This is a schematic diagram of the thermogravimetric analysis apparatus described in Example 2;

[0033] Figure 4 This is a schematic diagram of the thermogravimetric analysis apparatus described in Example 3.

[0034] The components include: 1. Fluidized bed reactor; 2. Buffer chamber; 3. Plasma synthesis jet generator; 4. Pressure monitoring equipment; 5. Weighing equipment; 6. Flow controller; 7. Quick connector; 8. Inlet pipe; 9. Outlet pipe; 10. First hose; 11. Second hose; 12. Third hose; 13. First check valve; 14. Second check valve; 101. Connecting pipe section; 102. Heating pipe section; 103. Reaction pipe section; 104. Top cover; 105. Air distribution plate; 106. Heat-conducting plate; 107. Heating equipment; 108. Thermocouple; 1031. Equal diameter reaction section; 1032. Gradually expanding buffer section; 1041. Top cover body; 1042. Tail gas pipe; 201. Carrier gas inlet; 202. Carrier gas outlet; 203. Pressure tap; 301. First discharge electrode; 302. Second discharge electrode; 303. Power supply. Detailed Implementation

[0035] To make the technical problems solved by the present invention, the technical solutions, and the beneficial effects clearer, the following specific embodiments provide a further detailed description of the present invention. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0036] Example 1

[0037] As attached Figure 1 As shown, this embodiment 1 provides a reactor for thermogravimetric analysis in a micro fluidized bed, comprising, from top to bottom, a connecting pipe section 101, a heating pipe section 102, a reaction pipe section 103, a top cover 104, an air distribution plate 105, a heat-conducting plate 106, a heating device 107, and a thermocouple 108 connected in sequence; wherein, the lower port of the connecting pipe section 101 is an air inlet port, the upper port of the connecting pipe section 101 is connected to the lower port of the heating pipe section 102, the upper port of the heating pipe section 102 is connected to the lower port of the reaction pipe section 103, and the top cover 104 is disposed at the upper port of the reaction pipe section 103; preferably, the connecting pipe section 101, the heating pipe section 102, and the reaction pipe section 103 are all hollow quartz tube structures, and the top cover 104, the air distribution plate 105, and the heat-conducting plate 106 are all quartz material components.

[0038] In this embodiment 1, the lower end of the connecting pipe section 101 is used to connect to the gas source. The connecting pipe section 101 serves as a handheld part, facilitating the handling of the reactor and enabling the addition of fluidizing medium and cleaning of the reactor. The inner wall of the heating pipe section 102 has a sinusoidal waveform structure. The inner wall of the sinusoidal waveform structure is designed to resemble a squid fin. By setting the inner wall of the sinusoidal waveform structure to resemble a squid fin, the heating area of ​​the fluidizing medium is effectively increased, greatly enhancing the heat transfer efficiency. An air distribution plate 105 is provided at the connection between the connecting pipe section 101 and the heating pipe section 102. The carrier gas can flow from the connecting pipe section 101 to the bottom of the air distribution plate 105 and smoothly enter the heating pipe section 102 and the reaction pipe section 103 through the action of the air distribution plate 105.

[0039] A heat-conducting plate 106 is provided in the heating tube section 102, and the heat-conducting plate 106 is located at a preset position above the air distribution plate 108. By adding a heat-conducting plate in the heating tube section, the heat conduction performance of the heat-conducting plate is utilized to significantly improve the heat transfer efficiency while promoting the uniformity of temperature distribution in the reactor, thereby increasing the heating rate of the fluidized medium. Preferably, the heat-conducting plate 106 is a curved plate structure with a preset thermal conductivity. Designing the heat-conducting plate as a curved plate structure increases the contact area between the heat-conducting plate and the fluidized medium, effectively improving the heat transfer efficiency of the heat-conducting plate.

[0040] The reaction section 103 includes a constant-diameter reaction section 1031 and a gradually expanding buffer section 1032. The lower port of the constant-diameter reaction section 1031 is connected to the upper port of the heating section 102, and the upper port of the constant-diameter reaction section 1031 is connected to the lower port of the gradually expanding buffer section 1032. The upper port of the gradually expanding buffer section 1032 is tightly connected to the lower end of the top cover 104. Designing the reaction section as a combination of sequentially connected constant-diameter reaction sections and gradually expanding buffer sections allows the carrier gas to have a large flow cross-section, ensuring a stable flow of gas within the reactor. This, in turn, ensures the stability of both the carrier gas and the exhaust gas, ultimately resulting in a smooth measurement curve. Simultaneously, within the gradually expanding buffer section, particles carried by the fluidization process can separate from the gas, reducing particle entrainment in the exhaust gas and thus minimizing measurement disturbances.

[0041] The top cover 104 is provided with a central through hole; wherein, the lower end of the central through hole communicates with the inner cavity of the reaction tube section 103, and the upper end of the central through hole communicates with the top surface of the top cover 104; the top cover 104 includes a top cover body and an exhaust pipe, wherein the lower end of the top cover body is fitted into the upper port of the gradually expanding buffer section 1032, and the exhaust pipe is concentrically arranged at the upper end of the top cover body; wherein, a first through hole is opened in the center of the top cover body, and a second through hole is opened in the center of the exhaust pipe, and the first through hole and the second through hole communicate to form the central through hole; the outer surfaces of the top cover body and the exhaust pipe are designed with a frosted surface structure, and the top cover body and the gradually expanding buffer section 1032 are sealed with a frosted surface.

[0042] The heating device 107 is disposed on the outside of the heating tube section 102 and is used to heat the internal cavity of the heating tube section 102; preferably, the heating device 107 is a heating furnace; the top cover 104 is provided with a thermocouple insertion port, specifically the thermocouple inlet is located on the top cover body and is disposed near the exhaust pipe; the thermocouple 108 is inserted into the internal cavity area of ​​the heating tube section 102 through the thermocouple insertion port and is used to monitor the temperature of the internal cavity area of ​​the heating tube section 102 in real time.

[0043] Working principle:

[0044] In the reactor described in Example 1 for micro fluidized bed thermogravimetric analysis, during use, carrier gas or air rises from the connecting pipe section 101 to the air distribution plate 105. Under the action of the air distribution plate 105, the fluidizing medium in the heating pipe section 102 and the reaction pipe section 103 presents a uniform fluidized state. The exhaust gas passes through the center of the top cover and enters the subsequent equipment for detection. The heating device 107 is used to heat the internal cavity of the heating pipe section 102, and the thermocouple 108 is used to monitor the temperature of the internal cavity area of ​​the heating pipe section 102 in real time.

[0045] In this embodiment 1, the inner wall of the heating tube section 102 is designed as a sinusoidal waveform structure resembling a squid fin. This structural adjustment increases the heating area of ​​the fluidizing medium, significantly enhancing heat transfer efficiency. By setting the heat-conducting plate 106, the heat transfer efficiency is greatly improved while promoting the uniformity of temperature distribution within the reactor, thereby increasing the heating rate of the fluidizing medium and making the experimental results more reliable. The reaction tube section 103 is designed as a combination of a constant-diameter reaction section 1031 and a gradually expanding buffer section 1032, resulting in a larger flow cross-section for the mixing of carrier gas and gaseous products. This allows the gas to flow smoothly within the reactor, making the carrier gas and exhaust gas more stable and resulting in smoother measurement curves. Furthermore, particles carried by the fluidization can be separated from the gas through the gradually expanding buffer section 1032, reducing microparticle entrainment and measurement disturbances. By installing thermocouples, the temperature of the reactants can be monitored in real time, making the experimental results more scientific.

[0046] Simulation:

[0047] In this Example 1, to verify the structural advantages of the reactor used for microfluidic bed thermogravimetric analysis, Fluent was used to simulate the heating and reaction sections of the reactor used for microfluidic bed thermogravimetric analysis in Example 1 and a traditional reactor. The example used was a reaction in which 90% SiC and 10% Fe2O3 particles were added to the reactor as the solid phase of the reaction system, and 10% CH4 and 90% N2 were introduced to reduce Fe2O3 with CH4. The inlet gas velocity of the reactor was set to 8 cm / s, the temperature to 1073℃, and the gas-solid fluidization was performed using an Euler two-fluid model. Simultaneously, the energy equation and radiation model were applied, indicating that the reaction process was endothermic.

[0048] The reaction equations for the above reaction process are as follows:

[0049] CH4 + 4Fe2O3 → CO2 + 2H2O + 8FeO ΔH θ =268.9 kJ / mol

[0050] As attached Figure 2 As shown, attached Figure 2 Temperature distribution curves in the reactor of Example 1 and a conventional reactor; from Appendix Figure 2 As can be seen, the temperature inside the reactor used for thermogravimetric analysis of micro fluidized beds in Example 1 is not as high as that inside a traditional reactor. This verifies that the reactor described in Example 1 enhances the heat transfer between the bed and the fluidizing medium, accelerates the reaction of CH4 and Fe2O3, and is more conducive to promoting a uniform temperature distribution inside the reactor, and also has higher heat transfer efficiency.

[0051] Example 2

[0052] As attached Figure 3 As shown, this embodiment 2 provides a thermogravimetric analysis device, including a fluidized bed reactor 1, a buffer gas chamber 2, a plasma synthesis jet generator 3, a gas pressure monitoring device 4, a weighing device 5, a quick connector 7, an air inlet pipe 8, an air outlet pipe 9, a first hose 10, a second hose 11, and a third hose 12.

[0053] The fluidized bed reactor 1 is disposed above the buffer gas chamber 2. The fluidized bed reactor 1 is a reactor used for micro fluidized bed thermogravimetric analysis as described in Embodiment 1 above. The buffer gas chamber 2 is fixedly disposed above the weighing device 5. The weighing device 5 is used to monitor the mass information of the fluidized bed reactor 1 and the buffer gas chamber 2 in real time. Preferably, the weighing device 5 is a weighing sensor.

[0054] A carrier gas inlet 201 is provided on one side of the buffer gas chamber 2, and a pressure tapping port 202 is provided on the other side of the buffer gas chamber 2. A carrier gas outlet 203 is provided on the top of the buffer gas chamber 2. The carrier gas inlet 201 is connected to a gas source through the air inlet pipe 8, and the gas source is an air source. A plasma synthesis jet generator 3 is also provided between the air inlet pipe 8 and the air source. A first one-way valve 13 is provided at the inlet end of the plasma synthesis jet generator 3, and a second one-way valve 14 is provided at the outlet end of the plasma synthesis jet generator 3.

[0055] In this embodiment 2, the plasma synthesis jet generator 3 includes a cavity, a first discharge electrode 301, a second discharge electrode 302, and a power supply 303; one end of the cavity has a first opening, and the other end of the cavity has a second opening; the first discharge electrode 301 is disposed at the top inside the cavity, and the second discharge electrode 302 is disposed at the bottom inside the cavity; both the first discharge electrode 301 and the second discharge electrode 302 are connected to the power supply 303, and the power supply 303 is used to supply power to the first discharge electrode 301 and the second discharge electrode 302; wherein, the first opening serves as the inlet end of the plasma synthesis jet generator 3, and the second opening serves as the outlet end of the plasma synthesis jet generator 3; the first one-way valve 13 is disposed at the first opening, and the second one-way valve 14 is disposed at the second opening.

[0056] The working principle of the plasma synthesis jet generator is as follows:

[0057] The plasma synthesis jet generator, based on the fundamental principle of plasma synthesis jet, operates by rapidly expanding the gas in the cavity at high temperature when the first discharge electrode 301 and the second discharge electrode 302 discharge together. This gas then enters the buffer chamber 2 through the second one-way valve 14. When the temperature and pressure inside the cavity decrease, outside air enters the cavity through the first one-way valve 13, thus achieving periodic discharge. It should be noted that the inlet of the plasma synthesis jet generator can be connected to either an air source or a compressed air cylinder to complete the fluidization reaction in an air atmosphere. The fluidization effect is controlled by adjusting the discharge time, frequency, and power of the plasma synthesis jet generator to regulate the outlet pressure and velocity of the gas flow. The plasma synthesis jet generator has significant advantages in size and weight, which can conveniently provide gas power for the fluidized bed, thereby improving the fluidization effect.

[0058] A pressure monitoring device 4 is provided at the pressure tap 202, and the pressure monitoring device 4 is a differential pressure sensor; wherein, the differential pressure sensor is connected to the pressure tap 202 by a first flexible hose 10; specifically, one end of the first flexible hose 10 is connected to the pressure tap 202, and the other end of the first flexible hose 101 is connected to the air inlet of the differential pressure sensor.

[0059] The lower end of the connecting pipe section 101 in the fluidized bed reactor 1 is connected to the carrier gas outlet 203; specifically, the fluidized bed reactor 1 and the carrier gas outlet 203 are connected by the quick connector 7, the upper end of the quick connector 7 is connected to the lower end of the connecting pipe section 101, and the lower end of the quick connector 7 is connected to the carrier gas outlet 203.

[0060] One end of the outlet pipe 9 is connected to the upper end of the central through hole in the fluidized bed reactor 1, and the other end of the outlet pipe 9 is used to connect to a gas chromatograph or mass spectrometer; the carrier gas inlet 201 is connected to the inlet pipe 8 by a second flexible hose 11, and the outlet pipe 9 is connected to the upper end of the central through hole by a third flexible hose 12; preferably, the first flexible hose 10, the second flexible hose 11 and the third flexible hose 12 are all rubber hoses.

[0061] Working principle:

[0062] In the thermogravimetric analysis device described in Embodiment 2, a fluidizing medium is loaded into the fluidized bed reactor 1, and then the reactor containing the fluidizing medium is installed above the buffer gas chamber 2. Next, the plasma synthesis jet generator is turned on to ventilate the reactor. Air enters the buffer gas chamber 2 through the inlet pipe 8 of the plasma synthesis jet generator for buffering. A pressure tap 202 is set on the right side of the buffer gas chamber 2, and a differential pressure sensor is installed at the pressure tap 202. The differential pressure sensor is used to monitor the gas pressure in the buffer gas chamber 2 in real time.

[0063] In this embodiment 2, the buffer gas chamber 2 is connected to the air inlet pipe 8 and the differential pressure sensor using rubber hoses; the carrier gas outlet of the buffer gas chamber 2 is connected to the connecting pipe section 101 via a quick connector 7; preferably, the length of the connecting pipe section 101 is 10cm, which facilitates the placement and removal of the fluidized bed reactor 1 to enable the addition of fluidizing medium and the cleaning of the reactor; the carrier gas rises through the connecting pipe section 101 to the air distribution plate 105, and under the action of the air distribution plate 105, the fluidizing medium is in a uniform fluidized state.

[0064] In this embodiment 2, the inner wall of the heating tube section 102 in the fluidized bed reactor 1 is designed with a sinusoidal waveform structure resembling squid fins, increasing the contact area between the tube wall and the fluidizing medium, thereby increasing the heating area of ​​the fluidizing medium and improving heating efficiency. The reaction tube section 103 in the fluidized bed reactor 1 is designed as a combination of a constant-diameter reaction section and a gradually expanding buffer section. By lengthening the reaction tube section 103, the problem of blowing out small particles is effectively solved. The top cover body adopts a hollow structure, and a tail gas pipe is set at the upper end of the top cover body. The tail gas pipe is used as a hand handle, and the outer surfaces of the tail gas pipe and the top cover body are both set with a frosted surface structure. The outlet end of the tail gas pipe is connected to the gas outlet pipe through a rubber hose. After the tail gas is discharged through the tail gas pipe, it enters a gas chromatograph or mass spectrometer for gas phase analysis through the gas outlet pipe. After a certain period of gas supply, if there is no significant change in mass, the heating equipment is turned on to heat the reactor, and the weight loss of the fluidizing medium under heating conditions and different gas pressure conditions is analyzed.

[0065] Example 3

[0066] As attached Figure 4 As shown, the thermogravimetric analysis device provided in this embodiment 3 has the same structure and principle as the thermogravimetric analysis device described in embodiment 2 above. The difference is that in this embodiment 3, the gas source is a gas storage cylinder containing carrier gas, and the plasma synthesis jet generator 3, the first one-way valve 13 and the second one-way valve 14 are replaced by an added flow controller 6 on the air inlet pipe 8. The remaining structures in this embodiment 3 are the same as those in embodiment 2, and will not be described again here.

[0067] Working principle:

[0068] In the thermogravimetric analysis device described in this embodiment 3, gas is supplied by a gas storage cylinder. The carrier gas enters the buffer gas chamber 2 after passing through the flow controller 6 for buffering. After buffering, the carrier gas passes through the connecting pipe section 101 and then through the air distribution plate 105 to enter the heating pipe section 102 and the reaction pipe section 103, so that the fluidizing medium is in a fluidized state.

[0069] The thermogravimetric analysis apparatus described in this invention mainly studies the factors affecting the generation of false masses in fluidized bed reactors by conducting tests at ambient temperature. Nitrogen is used as the carrier gas, and quartz sand, glass beads, and ZSM molecular sieves are selected as fluidization media for fluidization experiments. The effects of gas flow rate, particle size, bed mass, and particle type on false masses are analyzed based on weight loss data and gas pressure changes.

[0070] In this invention, the pyrolysis of fluidized media under high-temperature conditions is studied to analyze the influencing factors of gas-solid heterogeneous reactions and gas-phase homogeneous reactions. Based on the gas production rate, the Arrhenius equation kinetic equation is modified to establish a more accurate kinetic equation describing the reaction process, which can provide experimental comparative analysis for subsequent pyrolysis and gasification simulation studies. For example, the pyrolysis reaction of Ca(OH)2 is used as a test object under high-temperature conditions. By setting different heating rates and gas flow rates, the effects of temperature and gas flow rate on the reaction can be studied separately. At the same time, the pyrolysis activation energy and kinetic function can be further studied.

[0071] The fluidized bed reactor described in this invention can be applied to thermogravimetric analysis. The reactor has a small structural size, which can ensure that the reactions in the reaction zone are carried out uniformly to the greatest extent. Furthermore, its structural design can ignore the influence of internal gas backmixing. The fluidized reaction conditions can effectively eliminate the influence of gas diffusion and create an isothermal reaction zone with uniform gas-solid distribution and vigorous movement of solid particles.

[0072] In this invention, by adjusting the structure of the inner wall of the heating tube section and adopting a sinusoidal waveform structure similar to squid fins, the heating area of ​​the reactants is increased, greatly enhancing the heat transfer efficiency. A curved heat-conducting plate is added to the upper end of the air distribution plate, further increasing the heat transfer area. This also enhances heat transfer, enabling the sample to reach the experimental requirements in a short time, reducing the temperature difference of the sample, and thus improving the reliability of the experimental results. A thermocouple is installed at the top of the reactor to monitor the temperature of the reactants in real time, making the experimental results more scientific.

[0073] The thermogravimetric analysis device of the present invention uses a buffer gas chamber at the bottom of the fluidized bed reactor to slow down the carrier gas velocity and reduce the impact of gas velocity on mass. The reactor or buffer gas chamber is connected to other components by rubber hoses, which facilitates the removal of the reactor to add different reactants during experiments and reduces the influence of the gravimetric sensor.

[0074] Because the carrier gas affects the reactor mass during the experiment, it has a certain impact on the collection of mass changes in the experimental results. In this invention, a buffer gas chamber is installed at the bottom of the reactor and connected to the bottom of the reactor with a quick connector, thereby reducing the gas velocity and minimizing the impact of gas velocity on mass, thus improving the accuracy of the experiment. Regarding the connection method between the fluidized bed reactor and the equipment gas path, since different reactants need to be removed from the reactor during the experiment, and considering the sensitivity of the weighing equipment, a rubber hose is used for the interface connection. This ensures the accuracy of mass data and facilitates the removal of the reactor to add reagents during the experiment, greatly improving experimental efficiency. When using a plasma synthesis jet generator for gas supply, it offers advantages such as small size, low noise, low power consumption, ease of operation, maintenance-free operation, and continuous 24-hour operation. Furthermore, it does not require lubricating oil, so it will not contaminate the working medium or interfere with the analysis of the medium, and it is much cheaper, offering a higher cost-performance ratio compared to using gas cylinders.

[0075] The reactor and thermogravimetric analysis device for micro fluidized bed thermogravimetric analysis described in this invention employ a plasma synthesis jet generator connected to a gas source, or a flow controller when a gas storage cylinder is used as the gas source, to achieve precise control of the fluidized carrier gas. The heating equipment uses a heating furnace with excellent heating performance, enabling rapid heating and automatic temperature adjustment based on the detection results. The reactor is required to withstand high temperatures, therefore its overall structure is typically a cylindrical quartz tube. A tail gas pretreatment device can be added to the outlet end of the gas outlet pipe, or it can be connected to other detection instruments such as a chromatograph according to actual needs. In addition, necessary auxiliary components such as PLCs and various sensors can also be designed.

[0076] The reactor and thermogravimetric analysis device for micro fluidized bed thermogravimetric analysis described in this invention employs corrugated plates inside the reactor to enhance airflow disturbance and strengthen gas-solid heat and mass transfer. The corrugated structure on the inner wall increases the contact area between the wall and the fluidizing medium, enhancing heat transfer between the bed and the wall. This allows heat from the furnace to be transferred more evenly to the bed through the wall, further promoting axial bed temperature uniformity. This enables the micro fluidized bed reactor to enhance gas-solid heat transfer within a limited heat exchange area, closely approximating the fluidized bed operating conditions in industrial production. Simultaneously, an air inlet is designed at the bottom of the reactor... The invention incorporates a buffer chamber, increases the airflow cross-section, reduces pressure pulsation in the gas supply system, minimizes the impact of airflow on high-precision mass sensors, and improves the accuracy of mass signals. It proposes two gas supply methods: traditional compressed gas cylinder supply and plasma synthetic jet generator supply. The plasma synthetic jet generator, based on the fundamental principle of plasma synthetic jets, regulates the outlet pressure and velocity of the gas flow by adjusting the discharge time, frequency, and power. It offers significant advantages in size and weight, conveniently providing gas power for fluidized beds and further enhancing fluidization effects.

[0077] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

Claims

1. A thermogravimetric analysis apparatus, characterized in that, It includes a fluidized bed reactor (1), a buffer chamber (2), a weighing device (5), an inlet pipe (8), and an outlet pipe (9); The fluidized bed reactor (1) is a reactor used for micro fluidized bed thermogravimetric analysis; the reactor used for micro fluidized bed thermogravimetric analysis includes a connecting pipe section (101), a heating pipe section (102) and a reaction pipe section (103) connected sequentially from bottom to top. The lower end of the connecting pipe section (101) is used to connect to the air source. An air distribution plate (105) is provided at the connection between the connecting pipe section (101) and the heating pipe section (102). The inner wall of the heating pipe section (102) has a sinusoidal waveform structure. A heat-conducting plate (106) is provided in the heating pipe section (102). The heat-conducting plate (106) is located at a preset position above the air distribution plate (105). The upper end of the reaction tube section (103) is provided with a top cover (104), and the top cover (104) is provided with a central through hole; wherein, the lower end of the central through hole is connected to the inner cavity of the reaction tube section (103), and the upper end of the central through hole is connected to the top surface of the top cover (104). The buffer chamber (2) is fixedly installed above the weighing device (5); the weighing device (5) is used to monitor the mass of the fluidized bed reactor (1) and the buffer chamber (2) in real time. A carrier gas inlet (201) is provided on one side of the buffer gas chamber (2), and the carrier gas inlet (201) is connected to the gas source through the air inlet pipe (8); a pressure tap (202) is provided on the other side of the buffer gas chamber (2), and a pressure monitoring device (4) is provided at the pressure tap (202). The buffer gas chamber (2) is provided with a carrier gas outlet (203) at the top; the fluidized bed reactor (1) is located above the buffer gas chamber (2), and the lower port of the connecting pipe section (101) in the fluidized bed reactor (1) is connected to the carrier gas outlet (203). One end of the outlet pipe (9) is connected to the upper end of the central through hole in the fluidized bed reactor (1), and the other end of the outlet pipe (9) is used to connect to a gas chromatograph or a mass spectrometer. When the gas source is an air source, a plasma synthesis jet generator (3) is provided between the air inlet pipe (8) and the air source, and a first one-way valve (13) is provided at the inlet end of the plasma synthesis jet generator (3), and a second one-way valve (14) is provided at the outlet end of the plasma synthesis jet generator (3). The plasma synthesis jet generator (3) includes a cavity, a first discharge electrode (301), a second discharge electrode (302), and a power supply (303); one end of the cavity has a first opening, and the other end of the cavity has a second opening; the first discharge electrode (301) is located at the top inside the cavity, and the second discharge electrode (302) is located at the bottom inside the cavity; the first discharge electrode (301) and the second discharge electrode (302) are both connected to the power supply (303), and the power supply (303) is used to supply power to the first discharge electrode (301) and the second discharge electrode (302); wherein, the first opening serves as the inlet end of the plasma synthesis jet generator (3), and the second opening serves as the outlet end of the plasma synthesis jet generator (3); the first one-way valve (13) is located at the first opening, and the second one-way valve (14) is located at the second opening.

2. The thermogravimetric analysis apparatus according to claim 1, characterized in that, The heat-conducting plate (106) is a curved plate structure with a preset thermal conductivity.

3. The thermogravimetric analysis apparatus according to claim 1, characterized in that, The reaction tube section (103) includes a constant diameter reaction section (1031) and a gradually expanding buffer section (1032); the lower port of the constant diameter reaction section (1031) is connected to the upper port of the heating tube section (102), the upper port of the constant diameter reaction section (1031) is connected to the lower port of the gradually expanding buffer section (1032), and the upper port of the gradually expanding buffer section (1032) is sealed to the lower end of the top cover (104).

4. The thermogravimetric analysis apparatus according to claim 1, characterized in that, It also includes a heating device (107) and a thermocouple (108); the heating device (107) is located on the outside of the heating tube section (102); the top cover (104) is provided with a thermocouple insertion port, and the thermocouple (108) is inserted into the inner cavity area of ​​the heating tube section (102) through the thermocouple insertion port.

5. The thermogravimetric analysis apparatus according to claim 1, characterized in that, The air pressure monitoring device (4) uses a differential pressure sensor, and the differential pressure sensor is connected to the pressure tap (202) by a first flexible hose (10).

6. The thermogravimetric analysis apparatus according to claim 1, characterized in that, The air inlet (201) is connected to the air inlet pipe (8) by a second flexible hose (11), and the air outlet pipe (9) is connected to the upper end of the central through hole by a third flexible hose (12).

7. The thermogravimetric analysis apparatus according to claim 1, characterized in that, When the gas source is a gas storage cylinder containing carrier gas, a flow controller (6) is provided between the air inlet pipe (8) and the gas storage cylinder containing carrier gas; wherein, the flow controller (6) is used to control the flow rate of carrier gas in the air inlet pipe (8).

Images