Thermogravimetric analysis device and method for high-humidity multi-component atmosphere reaction kinetics research

Abstract

The application discloses a thermogravimetric analysis device and method for high-humidity multi-component atmosphere reaction kinetics research, and belongs to the technical field of thermogravimetric analysis instruments.The device comprises a reaction module, a heating furnace, a weighing module, a gas distribution module and an analysis module; the reaction module is vertically arranged in the heating furnace, and the core is a reaction tube main body which is open at the lower part; the side surface is connected with a gas inlet pipe and a sampling pipe from top to bottom; the weighing module is located below the reaction module and comprises a weighing balance, a water cooling unit and a weighing support rod; the water cooling unit can control the water vapor condensation area and stabilize the balance temperature; the gas distribution module can provide a multi-component reaction atmosphere containing controllable concentration water vapor; and the analysis module can detect the tail gas composition in real time.The application can realize low gas-solid mass transfer resistance, stable control of a high-humidity environment, wide particle size sample measurement and rapid temperature rise and fall, and is suitable for high-humidity multi-component atmosphere gas-solid reaction kinetics research in the fields of combustion, catalysis, adsorption and the like.

Description

Technical Field

[0001] This invention belongs to the field of thermogravimetric analysis instrument technology, specifically relating to a thermogravimetric analysis device and method for studying the reaction kinetics of multi-component atmospheres under high humidity. It is applicable to the kinetics of gas-solid reactions such as combustion, catalysis, adsorption, hydrogen production by methane steam reforming, hydrogen production by thermochemical water splitting, and oxygen absorption and release by perovskite oxygen carriers in fields such as energy and chemical engineering, materials science, and environmental science. In particular, it can meet the requirements for accurate measurement under high humidity (containing high concentration of water vapor) and multi-component mixed atmospheres. Background Technology

[0002] Thermogravimetric analysis (TGA) is a core technique for studying the kinetics of gas-solid reactions. By measuring the change in mass of substances with temperature and time under programmed temperature control and specific atmospheric conditions, it can obtain key kinetic parameters such as reaction rate and activation energy, providing important information for understanding reaction mechanisms, optimizing reaction conditions, and designing reaction apparatus. Precise measurement is a crucial prerequisite for revealing the kinetic laws; only through accurate measurement can reliable data be provided for in-depth investigation of reaction performance and optimization of process parameters. In the energy and chemical engineering field, reactions such as chemical looping for oxygen production, methane steam reforming for hydrogen production, and thermochemical water splitting for hydrogen production all require stable operation in high-humidity environments or complex multi-component atmospheres. Furthermore, parameters such as water vapor concentration and partial pressure of gas components in the reaction system significantly affect reaction kinetics. Therefore, there is an urgent need for thermogravimetric analysis equipment capable of precisely controlling high-humidity, multi-component atmospheres to support related research.

[0003] Existing thermogravimetric analyzers (TGAs) have significant drawbacks in high-humidity, multi-component atmosphere applications. Firstly, in high-humidity environments, water vapor easily condenses near the reaction tube or balance chamber. In traditional bottom-plate TGAs, condensate may flow into the balance, causing irreversible damage. Simultaneously, condensation alters the actual water vapor concentration in the reaction system, leading to a significant increase in measurement error. Furthermore, traditional open-tube furnaces struggle to stably control the partial pressure of gases in water-containing atmospheres, posing safety hazards, especially when flammable gases like H2 are involved (as disclosed in CN114755136A). While top-mounted suspended TGAs can address the water vapor condensation issue, data stability and accuracy are limited under high gas flow conditions. Secondly, existing TGAs are limited by their conventional inlet design and structural characteristics, resulting in poor mass transfer efficiency and particle size adaptability. Regarding particle size adaptability, the sample capacity of traditional TGAs is strictly limited by the size and volume of the crucible platform, typically only accommodating a small amount of powdered samples, making them unsuitable for large particles or samples with uneven composition. More importantly, powdered samples tend to stack, leading to uneven gas-solid contact and further amplifying measurement errors. Regarding mass transfer efficiency, existing commercial thermogravimetric analyzers (TGAs) mainly employ two types of inlet methods: vertical inlet and horizontal swirling inlet. Vertical inlet designs are prone to creating airflow stagnation zones, while horizontal swirling inlet designs are limited by the structure and position of the reaction tube and crucible, resulting in insufficient uniformity of airflow contact with the particle surface, and the mass transfer effect urgently needs optimization. Although fluidized bed thermogravimetric systems (such as CN114755136A and CN109030272A) attempt to improve mass transfer, their mass transfer effect is poor at low gas velocities, and equipment vibration causes mass signal fluctuations at high gas velocities. Furthermore, they are only suitable for narrow particle size ranges (fine powders are easily entrained, and large particles are difficult to fluidize). In addition, existing TGAs designed for large particles or large sample volumes have shortcomings in real-time monitoring of gaseous products. When relying on the outlet gas concentration to back-calculate kinetics, signal distortion is easily caused by gas backmixing and pipeline diffusion, especially for trace components such as O2, which are prone to "reaction tailing," making it impossible to achieve accurate correlation between mass changes and tail gas composition, which is particularly unfavorable for real-time monitoring.

[0004] While existing improvement schemes (such as optimizing reactor structure) can partially improve mass transfer, they still cannot solve the core problems of adaptability to high humidity atmospheres and wide particle size measurement. Furthermore, they rely solely on mass change data to establish kinetic models, lacking real-time verification of gaseous product concentrations, which affects the accurate construction of the model mechanism and causes the fitted parameters to deviate from the true values.

[0005] Therefore, developing a thermogravimetric analysis device and method that can accurately control high-humidity multi-component atmospheres, has low mass transfer resistance, is applicable to a wide range of particle sizes, and can monitor gaseous products in real time has become a key requirement for promoting the study of gas-solid reaction kinetics in high-humidity multi-component atmospheres. Summary of the Invention

[0006] In view of the above-mentioned deficiencies of the prior art, the present invention aims to provide a thermogravimetric analysis device for studying the reaction kinetics of high humidity and multi-component atmospheres. By optimizing the water cooling unit, improving the flow field structure of the reaction tube, and increasing the sampling port, the device can achieve accurate measurement of gas-solid reaction kinetics under high humidity and multi-component atmospheres.

[0007] To achieve the above objectives, the present invention provides a thermogravimetric analysis apparatus for studying the reaction kinetics of multi-component atmospheres under high humidity, comprising:

[0008] Heating furnace;

[0009] The reaction module is vertically installed inside the heating furnace and includes an air inlet pipe, a reaction tube body, and a sampling tube. The lower part of the reaction tube body is open. One end of the air inlet pipe and the sampling tube are both connected and fixed to the side of the reaction tube body and arranged from top to bottom. The inner diameter of the sampling tube is 1~10 mm.

[0010] The weighing module, located below the reaction module, includes a weighing balance, a water-cooling unit, and a weighing support rod. The weighing support rod comprises an upper tray and a lower support rod. The tray is positioned below the air inlet and above the sampling tube inlet, and a crucible with a diameter of 10-60 mm is placed on the tray, capable of measuring samples with a particle size range of 5 μm-5 cm. The water-cooling unit is located between the weighing balance and the reaction module, and includes a dehydration component and a water jacket component. The dehydration component is a cylindrical structure, with its top connected to the lower flange of the heating furnace and its bottom connected to the top of the water jacket component. The cylinder contains a cylindrical tube and a boss. The cylindrical tube has a height of 10-60 mm and an inner diameter of 5-20 mm. The boss has a hollow frustum or cone structure at its top, forming an angle of 5-70° with the vertical direction, and a height of 10-60 mm. mm, the material is a low thermal conductivity material; the water jacket component is a double-layer hollow structure, the inner layer is used to place a weighing balance, the interlayer is used to pass cooling water, and the water jacket component is connected to a gas pipeline with a diameter of 3~20 mm, and a silencer joint is installed at the end of the pipeline.

[0011] The gas distribution module includes a gas flow control unit, a gas preheating unit, a water vapor flow control unit, and a gas pipeline. The water vapor flow control unit generates water vapor through a humidity generator or a bubbler. The gas pipeline is connected to the inlet of the gas inlet pipe and is used to provide a multi-component reaction atmosphere.

[0012] The analysis module includes a second gas pipeline, a data acquisition unit, and a gas analysis device. The second gas pipeline is connected to the outlet of the sampling tube and is used to detect the composition of the reaction tail gas in real time.

[0013] Preferably, the intake pipe is a straight pipe, a coiled pipe, or a combination of a straight pipe and a coiled pipe, and the intake pipe is a constant diameter or an expanded diameter structure; the straight pipe section connecting the intake pipe and the main body of the reaction pipe is arranged horizontally or inclined, with an angle of -30 to 60° with the horizontal direction, and the length of the straight pipe section is 10 to 100 mm.

[0014] Preferably, the top of the reaction tube body is a cylinder of equal diameter or a truncated cone with a reduced diameter, the angle between the truncated cone with the vertical direction is 15~60°, and the height is 10~50 mm; the material of the reaction tube body is quartz, corundum or stainless steel, and if the top of the reaction tube body is made of quartz, it is frosted with a frosting height of 10~50 mm.

[0015] Preferably, the vertical distance between the weighing support rod tray and the air inlet outlet is 0~40 mm, and the vertical distance between the weighing support rod tray and the sampling tube inlet is 0~50 mm; the diameter of the tray is 20~80 mm, and the top of the tray adopts a horizontal air intake method.

[0016] Preferably, the cylinder of the water removal component is provided with a drain outlet and an exhaust outlet, the drain outlet is an intermittent drain outlet located at the bottom of the cylinder; the boss is made of polytetrafluoroethylene; the weighing support rod passes through the cylinder and the boss of the water removal component and is connected to the top of the weighing balance.

[0017] Preferably, the water jacket component has two water inlets, one at the top and one at the bottom, which are respectively connected to the inlet and outlet of the chiller; the water jacket component also has a protective air inlet, which is located at the bottom or side of the water jacket component, and the protective air flow rate is controlled at 10~100 mL / min; the front of the water jacket component has a flange, and the interior is fitted with a foot groove and an oblong hole for positioning and fixing the weighing balance.

[0018] Preferably, the weighing balance is a high-sensitivity balance with an accuracy of 0.1 mg or 0.01 mg, a weighing range of ≥50 g, and an integrated temperature control compensation module.

[0019] Preferably, the temperature control range of the heating furnace is 25~1600℃, and the heating furnace is a movable structure, which can realize the rapid separation of the heating temperature zone from the sample.

[0020] Preferably, the gas preheating unit of the gas distribution module adopts a coil structure, and the entire gas pipeline of the gas distribution module is heat-traced, with the heat tracing temperature maintained at ≥110℃; the gas analysis device of the analysis module is a gas chromatograph, mass spectrometer, flue gas analyzer, or infrared spectrometer.

[0021] Another aspect of the present invention provides a thermogravimetric analysis method for studying the reaction kinetics of multi-component atmospheres under high humidity, implemented using the aforementioned thermogravimetric analysis apparatus, comprising the following steps:

[0022] Step S1: Atmosphere Preparation

[0023] The flow rate of the multi-component reaction gas is adjusted by the gas flow control unit of the gas distribution module, and water vapor of a set concentration is generated by the water vapor flow control unit (humidity generator or bubbler). The multi-component reaction gas and water vapor are introduced into the gas preheating unit (coil structure) and preheated and mixed under the condition of heating temperature ≥110℃ to form a high-humidity multi-component reaction atmosphere.

[0024] Step S2: Sample Placement

[0025] Place the test sample (particle size 5 μm-5 cm) into the crucible, place the crucible on the tray of the weighing support rod, and adjust the position of the tray so that the vertical distance between the tray and the outlet of the air inlet is 0~40 mm and the vertical distance between the tray and the inlet of the sampling tube is 0~50 mm.

[0026] Step S3: Heating and Temperature Control

[0027] Start the heating furnace and set the temperature control program according to the reaction requirements: If rapid heating is required, first move the heating furnace to a position away from the sample, control the heating furnace to heat up to the specified temperature, but keep the sample area temperature below 70°C, then move the heating furnace to the outside of the reaction module to achieve rapid heating of the sample area, so that the heating rate of the sample area is in the range of 200~900°C / min, and finally maintain the temperature of the heating furnace and the sample area at the set reaction temperature of 25~1600°C;

[0028] Step S4: Simultaneous monitoring of air quality and exhaust emissions

[0029] The weighing balance and analysis module are started. The weighing balance collects the mass change data of the sample in real time (accuracy 0.01 mg). The water cooling unit maintains the ambient temperature of the weighing balance at <40℃ and the temperature fluctuation ≤±0.5℃. At the same time, the reaction tail gas enters the gas analysis device of the analysis module through the sampling tube to detect the composition and concentration of the tail gas in real time. The data acquisition unit records the mass change data and tail gas detection data simultaneously.

[0030] Step S5: Data Processing

[0031] Based on the mass change data and exhaust gas concentration data recorded by the data acquisition unit, sample mass-time curves and exhaust gas concentration-time curves are plotted. Combined with the reaction temperature parameters, a gas-solid reaction kinetic model is established to analyze the reaction kinetic laws.

[0032] Step S6: End of Experiment

[0033] After the reaction is complete, the system can be allowed to cool naturally under an inert atmosphere. Once the sample temperature has dropped to room temperature, the crucible can be removed for collection. Alternatively, the heating furnace can be quickly moved away from the reaction module to allow the sample to cool rapidly, and the crucible can be quickly transferred to a designated location to complete sample collection. Subsequently, the gas distribution module, analysis module, and water cooling unit should be shut down sequentially.

[0034] Preferably, in step S1, the multi-component reaction gas includes at least two of N2, O2, H2, CO2, CO, Ar, CH4, and NH3, the water vapor concentration is controlled at 10%~80% (volume fraction), and the preheating time of the gas preheating unit is 5~30 s; in step S4, the sampling frequency of the tail gas detection is 1~10 Hz, and the flow rate of the protective gas in the water cooling unit is controlled at 10~100 mL / min; in step S6, the maximum cooling rate of the sample is ≥500℃ / min, and the time to cool to <100℃ is ≤ 2 min.

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] (1) Optimization of low gas-solid mass transfer resistance: The method of combining CFD simulation and experimental verification was adopted. The flow and temperature field inside the reaction tube of the thermogravimetric analysis device were coupled and analyzed using computational fluid dynamics software. The influence of gas flow sweeping particle mode, furnace tube structure, and gas inlet and outlet structure on gas mixing efficiency and particle surface mass transfer process in the reaction tube was studied. The gas renewal rate of particle surface was enhanced by directional flow guidance, and the gas component concentration gradient in the reaction zone was reduced, thereby effectively reducing the reaction kinetic measurement deviation caused by mass transfer resistance. The test results are closer to the intrinsic chemical reaction rate of the material.

[0037] (2) Construction of high water vapor concentration environment: A modular steam generator is integrated at the inlet end, and the design of inlet coil and PID temperature control is adopted. The entire process of heat tracing pipeline ensures the stability of steam temperature in the reaction zone. The exhaust end is modified with a stepped water-cooled jacket, and an intermittent drain outlet is added. It is equipped with a polytetrafluoroethylene low thermal conductivity boss to form a gradient temperature field of >100℃ to <40℃ on the support rod, which completely prevents premature condensation of steam and moisture absorption of balance, and ensures the long-term stability and signal reliability of high humidity gas-solid reaction kinetic measurement.

[0038] (3) High stability and wide particle size applicability: The weighing balance adopts a high-precision integrated temperature control compensation module of 0.01 mg, with a weighing range of ≥50 g; the water-cooled jacket structure of the balance is optimized to create a stable weighing environment with a long-term temperature fluctuation of <±0.5℃ throughout the day; the wide-diameter tray and crucible are combined to measure samples with a particle size range of 5 μm-5 cm, which can accommodate large particles at the centimeter level and can also make micron-sized particles spread evenly, breaking through the particle size and sample volume limitations of traditional thermogravimetric analyzers.

[0039] (4) Rapid heating and cooling functions: Thanks to the movable furnace design, it can simulate the industrial feeding and rapid cooling process. Under the set temperature of 850℃, the sample area can maintain a low temperature of <70℃ before the sample is injected, and it can be rapidly heated to 800℃ within 75 seconds after the sample is injected, with a heating rate of over 600℃ / min. After the experiment, the heating temperature area and the sample can be quickly separated, with a cooling rate of ≥500℃ / min, which meets the testing requirements of rapid unsteady gas-solid reaction.

[0040] (5) Simultaneous monitoring of mass and exhaust gas: A dedicated sampling tube is integrated on the side of the reaction tube and paired with a high-precision gas analysis device to realize the synchronous real-time monitoring of sample mass change and exhaust gas component concentration. The time difference is ≤1 s, and there is no "reaction tailing" phenomenon. The accuracy of the kinetic model can be verified through exhaust gas data, which solves the model deviation problem caused by traditional thermogravimetric analyzers relying solely on mass data.

[0041] (6) Wide atmosphere and high temperature adaptability: The gas mixing module can realize the stable mixing of multi-component gases such as N2, O2, H2, CO2, CO, Ar, CH4, NH3 with 10%~80% volume fraction water vapor. The heating furnace temperature control range is 25~1600℃, which meets the testing requirements of various high humidity multi-component atmosphere gas-solid reactions such as combustion, catalysis, adsorption, hydrogen production, oxygen carrier oxygen absorption and release, etc., and has a wide range of applications.

[0042] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0043] Figure 1 : A schematic diagram of the overall structure of the thermogravimetric analysis device of the present invention;

[0044] Figure reference numerals: 1-1, Inlet pipe; 1-2, Reactor body; 1-3, Sampling tube; 2-1, Thermocouple; 2-2, Heating furnace; 3-1, Weighing balance; 3-2, Weighing support rod; 3-3, Crucible; 3-4, Dehydration component; 3-5, Water inlet; 3-6, Water jacket component;

[0045] Figure 2 The mass percentage change curve of the marble sample (50 mg) in Example 2 of this invention during the rapid heating to 850°C calcination process in the device of this invention;

[0046] Figure 3 Comparison curve of weight gain rate of CaO in situ carbonation reaction at 500℃ and 20% CO2 atmosphere in Example 2 of this invention;

[0047] Figure 4 The weight gain curve of CaO hydration reaction measured by the device in Example 3 of this invention at 500°C and 40% high humidity.

[0048] Figure 5 The airflow switching stability test curve of the device in Embodiment 4 of the present invention at a high temperature of 850℃. Detailed Implementation

[0049] The following description, with reference to the accompanying drawings, illustrates several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0050] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0051] Example 1

[0052] This embodiment provides a thermogravimetric apparatus for studying the reaction kinetics of high-humidity multi-component atmospheres, such as... Figure 1 As shown, it includes a reaction module, a heating furnace, a weighing module, a gas distribution module, and an analysis module.

[0053] The reaction module is vertically installed inside the heating furnace and includes an inlet pipe, a reaction tube body, and a sampling tube. The lower part of the reaction tube body is open. One end of both the inlet pipe and the sampling tube is connected and fixed to the side of the reaction tube body and arranged from top to bottom. The inner diameter of the sampling tube is 1-10 mm. The inlet pipe is a straight pipe, a coiled pipe, or a combination of a coiled pipe and a straight pipe, and has a constant diameter or expanded diameter structure. Preferably, the intake pipe is a combination of a coil and a straight pipe. The intake coil is connected to the top of the reaction pipe body in a "C" shape. The "C" shape includes three straight pipe sections with equal or expanded diameters. From top to bottom, they are (1) a horizontally or inclined straight pipe section, (2) a vertically or inclined straight pipe section, and (3) a horizontally or inclined straight pipe section connected to the top of the reaction pipe body. Preferably, the diameter of the equal diameter structure is 4~30 mm, and the diameter of the expanded diameter structure is 12~50 mm. The length of the three straight pipe sections of the intake pipe is 10~50 mm. The angle between (1) and (3) and the horizontal direction is -30~60°, and the angle between (2) and the vertical direction is -30~60°. The top of the reaction pipe body is an equal diameter cylinder or a reduced diameter frustum structure. The top of the reaction pipe body is connected to the straight pipe section (3) of the intake pipe. Preferably, the angle between the frustum structure and the vertical direction is 15~60°; the height of the frustum structure is 10~50 mm; the main body of the reaction tube is made of quartz material, the top is made of frosted material, and the frosting height is 10~100 mm; the heating furnace can achieve 25~1600℃.

[0054] The weighing module includes a weighing balance, a water-cooling unit, and a weighing support rod. The weighing module is located at the bottom of the reaction module. The water-cooling unit includes a dewatering component and a water jacket component to improve the stability of the weighing. The weighing support rod includes an upper tray and a lower rod. The weighing support rod passes through the groove and top boss of the stainless steel round tube and is connected to the top of the weighing balance.

[0055] The weighing balance integrates a temperature control compensation module, making it a high-sensitivity balance with a sensitivity of 0.1 mg or 0.01 mg and a weighing mass ≥20g. The balance chamber is equipped with a water-cooled jacket, with upper and lower inlet / outlet ports connected to a chiller, and wiring ports and a protective gas port. The protective gas port is located at the bottom or side of the water jacket. Further, the diameter of the protective gas port is 3-20 mm, and the local protective gas flow rate is optimized (10-100 mL / min). A silencer connector is placed at the inner end of the protective gas pipe within the water jacket to reduce the interference of airflow on the balance's stability. Water-cooled temperature control, combined with the protective gas port, uses inert gas purging to ensure temperature fluctuations ≤±0.5℃, eliminating the influence of ambient temperature changes on the weighing. Further, the water jacket is internally fitted with foot grooves and oblong holes for positioning and fixing the weighing balance. Preferably, the water jacket adopts a double-layer hollow structure, with a flange at the front for easy opening of the water jacket to adjust the balance and weighing support position.

[0056] The water-cooling component undergoes a stepped modification, comprising a cylinder. The top flange of the cylinder is connected to the lower flange of the furnace body, and the bottom is connected to the top of the water jacket component. The cylinder is equipped with a drain outlet and an exhaust outlet, the drain outlet being intermittent and located at the bottom of the dewatering device cylinder. Further, the cylinder's interior adopts a stepped design, consisting of a hollow stainless steel groove and a top boss. The top of the boss is a hollow frustum structure made of a low thermal conductivity material, preferably polytetrafluoroethylene (PTFE). This ensures that the temperature at the middle of the support rod is >100℃ to prevent condensation, and the temperature at the lower balance connection is <40℃. Preferably, the wall thickness of the hollow groove structure is 2-10 mm; the height of the hollow groove is 10-60 mm; and the inner diameter of the hollow groove is 5-20 mm. Preferably, the height of the frustum structure at the top of the boss is 10-60 mm, and the angle with the vertical direction is 5-60°.

[0057] The tray is positioned below the air inlet outlet and above the sampling tube inlet, with a vertical distance of 5-25 mm from the air inlet outlet and 0-50 mm from the sampling tube inlet. The tray features a horizontal air intake at the top, which enhances the gas renewal rate on the particle surface and reduces the concentration gradient in the reaction zone. Furthermore, the weighing module tray has a diameter of 20-80 mm, capable of accommodating both centimeter-sized large particles and allowing micron-sized particles to spread uniformly, reducing diffusion resistance caused by accumulation.

[0058] The gas distribution module includes a gas flow control unit, a gas preheating unit, a water vapor flow control unit, and gas pipelines; it is equipped with multiple gas source inlets. Water vapor is generated by a humidity generator or bubbler, passes through a mass flow meter, and then enters the fully heated pipeline to mix with other gases. The heating is maintained until the gas preheating pipe inlet, with the heating temperature kept above 110°C. The gas preheating pipe adopts a coil form, which increases the residence time, ensures stable steam temperature in the reaction zone, prevents condensation or stratification of water vapor and multi-component gases in the pipeline, and guarantees the stability of the atmosphere composition.

[0059] The analysis module includes a gas pipeline, data acquisition and analysis instruments. The gas pipeline is connected to the outlet at the bottom of the sampling tube and can be used with a variety of analysis instruments.

[0060] Example 2

[0061] This embodiment, based on the thermogravimetric analysis apparatus described in Embodiment 1, uses marble (mainly CaCO3) as the object to conduct a rapid heating and calcination reaction kinetics study on a large mass sample under high flow conditions and in situ carbonation. A comparative test was performed with a commercial thermogravimetric analyzer (model: TA Q5000 IR) at the same reaction temperature. This embodiment aims to verify the two core advantages of the apparatus of this invention: rapid heating and cooling function and optimized low gas-solid mass transfer resistance. The steps and parameters of the thermogravimetric analysis method are described in detail below:

[0062]

[0063] Figure 2 The mass percentage change curve of the marble sample shows that the device of this invention can achieve rapid heating, demonstrating that it can complete the calcination of large-mass samples in a very short time (on the order of hundreds of seconds). Generally speaking, the carbonation reaction (CaO + CO2 → CaCO3) kinetic process is mainly divided into two stages: the first stage is a rapid reaction period controlled by external gas film mass transfer and surface chemical reaction; the second stage is a slow reaction period controlled by diffusion within the product layer. The results are compared with those obtained by a commercial thermogravimetric analyzer (TAQ5000). Figure 3 Compared to the black curve, the device of the present invention (the present invention) Figure 3The weight gain curve (red curve) measured in Stage I exhibits an initial near-linear steep rise followed by a gradual flattening. Further analysis, combined with the reaction rate differential curve (Δm / Δt) in the inset, reveals that the reaction rate measured by the device of this invention reaches its peak value (~1.6) instantaneously at the start of the reaction. In contrast, the weight gain curve measured by the TAQ5000 shows an "S"-shaped lag in the induction period, with a significantly lower peak rate and a noticeable time delay. This indicates that the high-flow-rate directional flow and other structural optimizations of the device of this invention effectively reduce external gas film mass transfer resistance, bringing it closer to the intrinsic chemical reaction rate of the material. In summary, this invention, through the advantages of high-flow-rate directional flow and rapid heating, systematically overcomes the limitations of traditional testing methods and can effectively reduce reaction kinetic measurement deviations caused by mass transfer resistance.

[0064] Example 3

[0065] This embodiment, based on the thermogravimetric analysis apparatus described in Embodiment 1, uses marble (mainly CaCO3) as the object to conduct a rapid heating calcination study of a large mass sample under high flow conditions and an in-situ hydration reaction kinetic study under a high humidity atmosphere. The aim is to verify the operational stability and anti-condensation effect of the apparatus under high concentrations of water vapor (40%). The steps and parameters of the thermogravimetric analysis method are described in detail below:

[0066]

[0067] Figure 4 The CaO hydration reaction (CaO + H₂O → Ca(OH)₂) curve was demonstrated. Under 40% high humidity, the sample rapidly absorbed water, and the reaction curve was smooth and continuous. No sawtooth fluctuations or stepwise jumps in the mass signal caused by condensation or moisture in the balance chamber were observed throughout the process. This verifies the effectiveness of the high humidity environment construction and anti-condensation design of this invention: the inlet end uses a modular steam generator, PID precise temperature control, and a preheating unit to stably provide high-concentration water vapor; the exhaust end uses a stepped water-cooled protective sleeve to form a gradient temperature field from >100℃ to <40℃ on the support rod, supplemented by optimized protective gas, to completely prevent steam condensation and moisture absorption of the balance. This invention ensures the long-term stability and signal reliability of high-humidity gas-solid reaction kinetic measurements.

[0068] Example 4

[0069] This embodiment, based on the thermogravimetric analysis device described in Embodiment 1, conducts airflow switching stability and response tests under high-temperature conditions. The aim is to verify the stability and reliability of the mass signal response of the device under high-temperature environments and in the face of drastic changes in airflow conditions. The steps and parameters of the thermogravimetric analysis method are described in detail below:

[0070]

[0071] As attached Figure 5As shown, at each instant of gas flow rate or component switching, the mass signal exhibits a typical vertical step response without overshoot, oscillation, or tailing, indicating excellent system design, minimal dead volume, and the ability to achieve rapid gas replacement and instantaneous flow field stabilization. Under conditions of 850℃ high temperature and 2.5 L / min high flow rate, the baseline fluctuation amplitude of the mass signal remains less than ±0.01 mg (see...). Figure 5 The illustration in the lower right corner (the actual fluctuation range is even lower due to limitations in the weighing module's display accuracy) verifies that the device of this invention maintains extremely high measurement stability even under extreme operating conditions. Furthermore, after multiple switching operations, the mass reading accurately reproduces the initial reference value, demonstrating excellent measurement repeatability. In summary, the device of this invention possesses excellent flow field stability and rapid response characteristics, making it particularly suitable for studying unsteady gas-solid reaction processes involving rapid, periodic atmosphere switching, such as chemical looping combustion and adsorption cycles.

[0072] Example 5

[0073] This embodiment is based on the device described in Embodiment 1, and uses perovskite oxygen carrier as the object to carry out research on oxygen absorption and release kinetics under a high humidity multi-component atmosphere.

[0074] The sample was a 2 mm perovskite oxygen carrier with a mass of 100 mg; the oxygen absorption atmosphere was 20% oxygen + 20% water vapor (carrier gas was argon), and the oxygen release atmosphere was argon + 20% water vapor; the weighing balance was calibrated with a 50 g standard weight, with an error ≤0.01 mg; the micro oxygen analyzer was calibrated with a standard gas, covering a range of 0~25% oxygen, with an error ≤0.1%; the heating furnace thermocouple was calibrated, with a temperature error ≤±1℃.

[0075] Step S1: Atmosphere preparation. Control the argon flow rate to 1000 mL / min using a mass flow meter to form an inert atmosphere with a total flow rate of 1 L / min. Purge the reaction tube for 5 min.

[0076] Step S2: Sample placement. Spread the sample evenly on a 30 mm quartz crucible and place it on a tray. Adjust the distance between the tray and the outlet of the air inlet to 10 mm and the distance between the tray and the inlet of the sampling tube to 30 mm. Zero the balance and record the initial mass.

[0077] Step S3: Heating and temperature control. Initially, the heating furnace is far away from the sample, with the sample area at 65°C. Then, it is quickly moved to the reaction module, heated to 650°C, and then kept at a constant temperature.

[0078] Step S4: Atmosphere preparation. The oxygen flow rate is controlled at 200 mL / min and the argon flow rate at 500 mL / min by a mass flow meter. The argon flow rate is 100 mL / min carrying water vapor. The humidity generator is set to a water vapor concentration of 20% (corresponding to 200 mL / min). After preheating in a coil at 650℃, an oxygen-absorbing atmosphere with a total flow rate of 1 L / min is formed. The reaction tube is then purged for 5 minutes.

[0079] Step S5: Simultaneous monitoring of mass and exhaust gas. Mass data is collected by the balance at 5Hz. The water-cooling unit maintains the balance chamber at 25℃±0.3℃ and the protective gas flow rate at 30 mL / min. The exhaust gas enters the micro oxygen analyzer through a 3 mm sampling tube to detect the oxygen concentration and records the data simultaneously. Oxygen is inhaled at a constant temperature of 650℃ for 5 min until the mass stabilizes.

[0080] Step S6: Oxygen release reaction and data monitoring. Switch to an atmosphere of 800 mL / min argon + 20% water vapor, purge for 5 min, release oxygen at 650℃ for 10 min until the mass is stable, and record the data simultaneously. The oxygen absorption activation energy is 85 kJ / mol and the oxygen release activation energy is 92 kJ / mol. Establish an oxygen absorption and release kinetic model.

[0081] Step S7: After the experiment is over, quickly remove the heating furnace, cool to 100°C in 5 minutes, remove the sample after it reaches room temperature, and turn off the equipment.

[0082] Test results show that the oxygen carrier has an oxygen uptake capacity of 0.85 wt%, with a deviation of ≤ 2% from the theoretical value. The activation energy deviation in three repeated experiments is ≤ ±3 kJ / mol. The time difference between the mass and oxygen concentration signals is ≤ 1s. There is no obvious reaction tailing. The measurement accuracy is high, the repeatability is good, and the synchronization is excellent.

[0083] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A thermogravimetric analysis apparatus for studying the reaction kinetics of multi-component atmospheres under high humidity, characterized in that, include: Heating furnace; The reaction module is vertically installed inside the heating furnace and includes an air inlet pipe, a reaction tube body, and a sampling pipe. The lower part of the reaction tube body is open, and one end of the air inlet pipe and the sampling pipe are both connected and fixed to the side of the reaction tube body and arranged from top to bottom. A weighing module, located below the reaction module, includes a weighing balance, a water-cooling unit, and a weighing support rod. The weighing support rod comprises a tray and a support rod. The tray is positioned below the outlet of the air inlet pipe and above the inlet of the sampling pipe, and a crucible is placed on the tray. The water-cooling unit is located between the weighing balance and the reaction module, and includes a dehydration component and a water jacket component. The top of the dehydration component is connected to the lower flange of the heating furnace, and the bottom of the dehydration component is connected to the top of the water jacket component. The weighing balance is placed inside the water jacket component, and cooling water is introduced into the jacket. The cylinder of the dehydration component has a drain outlet and an exhaust outlet. The drain outlet is intermittent and located at the bottom of the cylinder. The interior of the cylinder adopts a stepped design, consisting of a circular tube at the bottom and a boss at the top. The top of the boss is a hollow frustum or cone structure made of a material with low thermal conductivity. The weighing support rod passes through the circular tube and the boss of the dehydration component and connects to the top of the weighing balance. The gas distribution module includes a gas flow control unit, a gas preheating unit, a water vapor flow control unit, and a gas pipeline. The water vapor flow control unit generates water vapor through a humidity generator or a bubbler. The gas pipeline is connected to the inlet of the gas inlet pipe and is used to provide a multi-component reaction atmosphere. The analysis module includes a second gas pipeline, a data acquisition unit, and a gas analysis device. The second gas pipeline is connected to the outlet of the sampling tube and is used to detect the composition of the reaction tail gas in real time.

2. The thermogravimetric analysis apparatus for studying reaction kinetics in high-humidity multi-component atmospheres as described in claim 1, characterized in that, The intake pipe is a straight pipe, a coil, or a combination of a straight pipe and a coil. The intake pipe is of equal diameter or expanded diameter. The straight pipe section connecting the intake pipe and the main body of the reaction pipe is arranged horizontally or inclined. The angle between the straight pipe section and the horizontal direction is -30° to 60°, and the length is 10 to 100 mm.

3. The thermogravimetric analysis apparatus for studying reaction kinetics in high-humidity multi-component atmospheres as described in claim 1, characterized in that, The top of the reaction tube body is a cylinder of equal diameter or a truncated cone with a reduced diameter. The angle between the truncated cone with the vertical direction is 15~60° and the height is 10~50 mm. The material of the reaction tube body is quartz, corundum or stainless steel.

4. The thermogravimetric analysis apparatus for studying reaction kinetics in high-humidity multi-component atmospheres as described in claim 1, characterized in that, The vertical distance between the tray and the air inlet outlet is 0~40 mm, and the vertical distance between the tray and the sampling tube inlet is 0~50 mm; the diameter of the tray is 20~80 mm, and the top of the tray adopts a horizontal air intake method.

5. The thermogravimetric analysis apparatus for studying reaction kinetics in high-humidity multi-component atmospheres as described in claim 1, characterized in that, The height of the circular tube is 10-60 mm, and the inner diameter is 5-20 mm.

6. The thermogravimetric analysis apparatus for studying reaction kinetics in high-humidity multi-component atmospheres as described in claim 1, characterized in that, The water jacket component has two water inlets, one at the top and one at the bottom, which are connected to the inlet and outlet of the chiller, respectively. The water jacket component also has a protective air inlet, which is located at the bottom or side of the water jacket component. The diameter of the protective air pipe is 3-20 mm, and a silencer connector is installed. The protective air flow rate is controlled at 10~100 mL / min.

7. The thermogravimetric analysis apparatus for studying reaction kinetics in high-humidity multi-component atmospheres as described in claim 1, characterized in that, The weighing balance is a high-sensitivity balance with an accuracy of 0.1 mg or 0.01 mg and a weighing range of ≥20 g. The weighing balance integrates a temperature control compensation module.

8. The thermogravimetric analysis apparatus for studying reaction kinetics in high-humidity multi-component atmospheres as described in claim 1, characterized in that, The heating furnace has a temperature control range of 25~1600℃ and is a movable structure, which enables rapid separation of the heating temperature zone from the sample.

9. The thermogravimetric analysis apparatus for studying reaction kinetics in high-humidity multi-component atmospheres as described in claim 1, characterized in that, The gas preheating unit adopts a coil structure, and the gas pipeline of the gas distribution module is heat-traced with a heat tracing temperature ≥110℃.

10. A thermogravimetric analysis method for studying the reaction kinetics of multi-component atmospheres under high humidity, characterized in that, Based on the thermogravimetric analysis apparatus according to any one of claims 1 to 9, the method comprises the following steps: Step S1: Atmosphere Preparation The flow rate of the multi-component reaction gas is adjusted by the gas flow control unit of the gas distribution module, and water vapor of a set concentration is generated by the water vapor flow control unit. The multi-component reaction gas and water vapor are preheated and mixed under the condition of heating temperature ≥110℃ to form a high-humidity multi-component reaction atmosphere, which is then introduced into the gas preheating unit. Step S2: Sample Placement Place the sample to be tested into the crucible, place the crucible on the tray of the weighing support rod, and adjust the position of the tray so that the vertical distance between the tray and the outlet of the air inlet is 0~40 mm and the vertical distance between the tray and the inlet of the sampling tube is 0~50 mm. Step S3: Heating and Temperature Control Start the heating furnace and set the temperature control program according to the reaction requirements: If rapid heating is required, first move the heating furnace to a position away from the sample, control the heating furnace to heat up to the specified temperature, keep the sample area temperature at <70℃, then move the heating furnace to the outside of the reaction module to achieve rapid heating of the sample area, so that the heating rate of the sample area is in the range of 200~900℃ / min, and finally maintain the temperature of the heating furnace and the sample area at the set reaction temperature of 25~1600℃; Step S4: Simultaneous monitoring of air quality and exhaust emissions The weighing balance and analysis module are started. The weighing balance collects the mass change data of the sample in real time. The water cooling unit maintains the ambient temperature of the weighing balance at <20℃ and the temperature fluctuation at ≤±0.5℃. At the same time, the reaction tail gas enters the gas analysis device of the analysis module through the sampling tube to detect the composition and concentration of the tail gas in real time. The data acquisition unit records the mass change data and tail gas detection data simultaneously. Step S5: Data Processing Based on the mass change data and exhaust gas concentration data recorded by the data acquisition unit, sample mass-time curves and exhaust gas concentration-time curves are plotted. Combined with the reaction temperature parameters, a gas-solid reaction kinetic model is established to analyze the reaction kinetic laws.

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