Thermogravimetric analysis device, control method and control device

Abstract

The invention provides a thermogravimetric analysis device, a control method and a control device. The thermogravimetric analysis device comprises: a reaction container having a reaction chamber, a gas inlet arranged on one side of the reaction chamber and a gas outlet arranged on the other side of the reaction chamber, the reaction chamber sequentially comprising a weight measuring chamber, a gas preheating chamber and a sample placing chamber along a direction from the gas inlet to the gas outlet; the air supply system is communicated with the air inlet; a gas preheating assembly of the heating system comprises a preheating element arranged in a gas preheating cavity, and an electric furnace of the heating system can move to a first position to heat the sample and can also move to a second position to stop heating the sample; and the measuring system comprises a weight measuring element fixedly arranged in the weight measuring cavity and a sample container arranged in the sample placing cavity, and the weight measuring element is arranged to measure the weight of the sample. According to the thermogravimetric analysis device, one-way plug flow of gas can be guaranteed, a stable gas atmosphere can be provided for reaction of a sample, and the accuracy of tail gas component measurement can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sample analysis, in particular to a thermal gravimetric analysis device, a control method and a control device. BACKGROUND

[0002] A thermal gravimetric analyzer (TGA) is an experimental device for analyzing the reaction characteristics of a sample by accurately measuring key signals such as mass and temperature during the thermal chemical conversion process of the sample under programmed temperature conditions. The device is widely used to obtain reaction characteristic data of solid samples in thermal chemical conversion processes such as drying, pyrolysis, gasification, and oxidation, and plays an important role in many fields such as chemical industry, geology, biology, energy, and environment.

[0003] In research, it is often necessary to simulate real industrial production conditions through experimental devices and record signals such as mass, temperature, and size of the sample during the reaction process, as well as gas composition. The processing and analysis of the corresponding experimental data can ultimately be used to describe the gas-solid reaction characteristics and guide the design of industrial reactors and the optimization of working conditions. Therefore, the key to an ideal experimental device is to provide similar working conditions to actual industrial production and to continuously, online, and accurately measure key experimental signals. However, existing experimental devices are difficult to achieve similar working conditions to actual industrial production and continuously, online, and accurately measure key experimental signals. SUMMARY

[0004] The embodiment of the present application provides a thermal gravimetric analysis device, which comprises: a reaction container having a reaction cavity, a gas inlet arranged on one side of the reaction cavity, and a gas outlet arranged on the other side of the reaction cavity, and along the direction from the gas inlet to the gas outlet, the reaction cavity comprises a weighing cavity, a gas preheating cavity, and a sample placement cavity arranged in sequence; a gas supply system in communication with the gas inlet; a heating system comprising a movable electric furnace and a gas preheating assembly, the gas preheating assembly comprising a preheating element arranged in the gas preheating cavity, the electric furnace being arranged to be movable to a first position where the sample placement cavity is located to heat the sample in the sample placement cavity, and to a second position away from the side of the sample placement cavity where the gas preheating cavity is located to stop heating the sample; and a measurement system comprising a weighing element fixedly arranged in the weighing cavity and a sample container arranged in the sample placement cavity, the weighing element being arranged to measure the weight of the sample in the sample container.

[0005] The embodiment of the present application provides a control method of a thermal gravimetric analysis device, which comprises: Controlling the gas supply system to supply gas into the reaction container so that the gas flows unidirectionally from the gas inlet to the gas outlet and maintains plug flow; controlling the preheating element of the heating system to heat the gas entering the reaction container so as to heat the sample in the sample placement cavity with the heated gas, and controlling the electric furnace of the heating system to move to the first position where the sample placement cavity is located so as to heat the sample in the sample placement cavity with the electric furnace; and The measuring system is controlled to measure parameter information of the sample.

[0006] An embodiment of the present application provides a control device for a thermogravimetric analysis device, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the computer program implements the steps of the control method described above when executed by the processor.

[0007] The thermogravimetric analysis device of the embodiment of the present application adopts an innovative gas path structure optimization design, which can take in air from one side of the reaction vessel and then exhaust air from the other side of the reaction vessel, so that the gas flows in one direction in the reaction vessel. Compared with some thermogravimetric analysis devices, which take in air from the upper and lower sides of the reaction vessel and exhaust air from the middle of the reaction vessel, the thermogravimetric analysis device of the embodiment of the present application realizes the directional transmission of gas by constructing a one-way closed flow channel. On the one hand, it can provide a stable gas atmosphere for the reaction of the sample, and on the other hand, it is also conducive to improving the accuracy of the measurement of the exhaust gas components. In addition, based on the design of the reaction vessel with a lower gas flow rate and a larger inner diameter, the linear velocity of the gas flow in the reaction chamber can be controlled within a smaller range, so that the flow state of the gas conforms to the fluid mechanics characteristics of the plug flow reactor, effectively suppressing the component concentration fluctuation caused by the back-mixing phenomenon in the traditional gas path design, and reducing the gas signal measurement error, thereby ensuring the time domain stability and value traceability of the detection data. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 Schematic diagram of the structure of the thermogravimetric analysis device according to some embodiments of the present application, wherein the electric furnace is in the second position; Figure 2 Schematic diagram of the structure of a thermogravimetric analysis device according to some embodiments of the present application, wherein the electric furnace is in a first position; Figure 3a A schematic diagram of the three-dimensional structure of a sample container of a thermogravimetric analysis device according to some embodiments of the present application; Figure 3b for Figure 3a A schematic diagram of the top view of the sample container shown; Figure 3c Schematic diagram of the three-dimensional structure of a sample container of a thermogravimetric analysis device according to some other embodiments of the present application; Figure 3d Fig. 1 is a schematic diagram showing the top view of a sample container according to an embodiment of the present application; Figure 3c Fig. 2 is a schematic diagram showing the top view of a sample container according to another embodiment of the present application; Figure 3e Fig. 3 is a schematic diagram showing the perspective view of a sample container of a thermal gravimetric analysis device according to yet some embodiments of the present application; Figure 3f Fig. 4 is a schematic diagram showing the top view of a sample container according to yet some embodiments of the present application; Figure 3e Fig. 5 is a schematic diagram showing the top view of a sample container according to yet some embodiments of the present application; Figure 4a Fig. 6 is a schematic diagram showing the perspective view of a heat shield of a thermal gravimetric analysis device according to some embodiments of the present application, wherein the heat shield is in a closed state; Figure 4b Fig. 7 is a schematic diagram showing the top view of a heat shield according to some embodiments of the present application; Figure 4a Fig. 8 is a schematic diagram showing the top view of a heat shield according to some embodiments of the present application; Figure 4c Fig. 9 is a schematic diagram showing the perspective view of a heat shield in the process of being opened according to some embodiments of the present application; Figure 4a Fig. 10 is a schematic diagram showing the top view of a heat shield according to some embodiments of the present application; Figure 4d Figure 4c Fig. 11 is a schematic diagram showing the top view of a heat shield according to some embodiments of the present application; Figure 4e Fig. 12 is a schematic diagram showing the perspective view of a heat shield in an open state according to some embodiments of the present application; Figure 4a Fig. 13 is a schematic diagram showing the top view of a heat shield according to some embodiments of the present application. Figure 4f Figure 4e Fig. 14 is a schematic diagram showing the top view of a heat shield according to some embodiments of the present application.

[0009] In the drawings, the components represented by the respective reference numerals are listed as follows: 1.1-gas cylinder, 1.2-flow detection unit, 1.3-control valve, 1.4-gas mixer, 1.5-gas inlet pipeline, 1.6-sealing cover, 1.7-reaction tube, 1.8-gas outlet pipeline, 1.9-gas inlet port, 1.10-gas outlet port; 2.1-induction coil, 2.2-preheating element, 2.3-induction heating power supply, 2.4-preheating temperature control element, 2.5-electric furnace guide rail, 2.6-heat shield, 2.61-base, 2.62-center hole, 2.63-blade, 2.64-link, 2.65-driving member, 2.66-sliding slot, 2.67-sliding column, 2.7-electric furnace, 2.8-heat tracing band; 3.1-weight measurement element, 3.2-wireless signal transmitter, 3.3-suspension wire, 3.4-temperature measurement element, 3.5-sample container, 3.51-shutter, 3.6-sample, 3.7-observation window, 3.8-high-speed camera, 3.9-infrared camera, 3.10-wireless signal receiver, 3.11-capillary tube, 3.12-gas analysis device. DETAILED DESCRIPTION

[0010] ​​The principles and features of the present application are described below in conjunction with the accompanying drawings, which are presented only for illustrative purposes and are not intended to limit the scope of the present application.

[0011] For the thermal gravimetric analyzer / thermal gravimetric analysis device, taking the simulation of the thermal chemical treatment of solid waste as an example, the main characteristics of the working conditions in actual industrial production include: (1) Most of the samples undergo a rapid (more than 1000 K / min) temperature rising process, and part of the samples undergo a slow (5-120 K / min) and medium (300-700 K / min) temperature rising process. After the solid waste samples are sent into the grate from the hopper, the temperature rising of the upper layer of samples is dominated by the radiation heat exchange of the high-temperature furnace wall and the flame and the convection heat exchange of the high-temperature gas, and the samples undergo rapid temperature rising, with a rate of more than 1000 K / min; the temperature rising of the bottom layer of samples is dominated by the solid heat conduction between the solid waste samples, and the temperature rising rate of the samples is relatively low, usually less than 120 K / min; the temperature rising rate of the middle layer of samples is between that of the top layer of samples and that of the bottom layer of samples. The research results show that the thermal chemical conversion characteristics of solid waste under different temperature rising rates may be significantly different. Therefore, the kinetic parameters calculated from the experimental data obtained under slow temperature rising using the conventional thermal gravimetric analysis device are usually difficult to accurately predict the reaction characteristics under rapid temperature rising. Therefore, it is necessary to carry out thermal chemical experiments of solid waste under different temperature rising rates, and an ideal experimental device should be able to provide experimental working conditions covering slow, medium and rapid temperature rising. (2) The sample size is large, usually in centimeter level. In order to reduce the sample pre-treatment cost, there is a considerable number of samples with a size in the range of 10-100 mm. The influence of diffusion and heat transfer of samples of different sizes during the reaction process is significantly different, therefore, an ideal experimental device needs to be able to accommodate large-size samples. In addition, a larger sample amount can effectively reduce the random error of experimental data. In addition to being able to provide similar working conditions to actual production, an ideal experimental device should also be able to directly obtain more comprehensive sample characteristic signals online: (a) Directly obtain the sample mass. The sample mass during the experiment is one of the important signals reflecting the kinetic characteristics of the thermal chemical conversion of the sample. (b) Directly obtain the sample temperature. On the one hand, temperature is an important signal for analyzing the kinetic characteristics during the thermal chemical conversion process of the sample and calculating the kinetic parameters; on the other hand, for large-size samples, the temperature gradient inside the sample can also reflect the heat transfer process inside the sample during the experiment. (c) Realize the visualization of the sample during the experiment. The image signal can reflect the size, shape and other characteristics of the sample, and is one of the important parameters for establishing a particle scale model. (d) Realize the continuous online measurement of the gas composition. The gas composition is an important parameter for analyzing the reaction process and verifying the reactor scale model.

[0012] Currently, conventional commercial thermal gravimetric analyzers usually have the following limitations: (1) Low heating rate. Limited by the working characteristics of the electric furnace, the rated heating rate of the heating system is usually 5-120 K / min, making it difficult to cover the medium and high heating rate range. (2) Difficult to accommodate large size samples. Due to the limitation of the reaction area space, the sample tray size is usually less than 4 mm, and the rated sample mass is usually not more than 50 mg. The sample is usually a micron-sized powder that is stacked, making it difficult to simulate the sample amount in actual industrial production scenarios. (3) Difficult to directly measure the sample temperature during the reaction. In order to prevent the direct contact of the thermocouple with the sample from affecting the stability of the mass measurement, the temperature in the vicinity of the sample is usually measured using a thermocouple. (4) Difficult to obtain image signals of the sample during the reaction in real time.

[0013] In order to overcome the limitations of traditional commercial thermal gravimetric analyzers, a number of research and achievements have emerged to address the challenges of rapid heating, wide range, visualization, etc.

[0014] Research results that achieve rapid heating include: (1) Heat insulation type (such as CN 107271320A). Before the experiment, the sample is prevented from being preheated by the high temperature environment by using a heat insulation device. After the experiment starts, the heat insulation device is quickly removed from the reaction area, and then the sample is exposed to the high temperature environment, thereby achieving the function of rapid heating. However, the heat insulation device can usually only delay the heating of the sample, and the vibration caused by the movement of the heat insulation device may affect the accuracy of the instrument mass measurement. (2) Transmission type (such as CN 106092803A), the sample is quickly sent from the room temperature area to the high temperature furnace by a transmission device, and the sample mass is measured by a specially designed weighing device. However, during the process of quickly sending the sample into the high temperature area, the vibration of the transmission device usually affects the accuracy of the instrument mass measurement. (3) Programmed heating type (such as CN 108956361A), a rapid heating program is set, and a light-heat heating component is used to heat the sample quickly. This method focuses on heat conduction and heat radiation for the sample, but does not enhance the convective heat transfer between the gas and the sample, making it difficult for the actual heating rate of the sample to reach the expected value.

[0015] The large range measurement function is mainly achieved by increasing the space of the reaction area and the size of the sample tray, as well as the range of the mass measurement device. The visualization function is mainly achieved by using high-speed cameras, etc. Typical research results such as CN 201811367886 use large-size wire mesh trays to achieve the function of carrying larger samples, while ensuring that the sample is heated uniformly without changing the appearance of the sample. The changes in the sample's appearance, size, and surface temperature are recorded by high-speed cameras and infrared cameras. However, the related experimental devices usually cannot achieve the function of rapid heating, and cannot obtain the internal temperature distribution information of the sample.

[0016] Based on defects of existing thermogravimetric analyzers / thermogravimetric analysis devices, the embodiments of the present application provide a thermogravimetric analysis device which can provide a fast heating condition for gas-solid reaction experiments of samples in a wide mass range, and continuously measure the sample mass, temperature and image signals and gas component signals during the experiment. In addition, the device can also provide slow and medium heating conditions.

[0017] As shown in Figure 1 and Figure 2 , the thermogravimetric analysis device provided by the embodiments of the present application includes a reaction container, a gas supply system, a heating system and a measurement system.

[0018] The reaction container has a reaction cavity, a gas inlet 1.9 arranged on one side of the reaction cavity, and a gas outlet 1.10 arranged on the other side of the reaction cavity, and along the direction from the gas inlet 1.9 to the gas outlet 1.10, the reaction cavity includes a weighing cavity, a gas preheating cavity and a sample placement cavity arranged in sequence.

[0019] The gas supply system is in communication with the gas inlet 1.9 and can provide gas for the reaction container.

[0020] The heating system includes a movable electric furnace 2.7 and a gas preheating assembly, the gas preheating assembly includes a preheating element 2.2 arranged in the gas preheating cavity, and the electric furnace 2.7 is arranged to be movable to a first position (as shown in Figure 1 ) at which the sample placement cavity is located to heat the sample 3.6 in the sample placement cavity, and movable to a second position (as shown in Figure 2 ) at which the sample placement cavity is away from the gas preheating cavity to stop heating the sample 3.6.

[0021] The measurement system includes a weighing element 3.1 fixedly arranged in the weighing cavity and a sample container 3.5 arranged in the sample placement cavity, and the weighing element 3.1 is arranged to measure the weight of the sample 3.6 in the sample container 3.5.

[0022] The thermal gravimetric analysis device of the embodiment of the present application is provided with a reaction cavity in the reaction container, and the sample 3.6 can react (such as thermal chemical treatment of solid waste) in the reaction cavity. One side of the reaction cavity is provided with a gas inlet 1.9, and the other side of the reaction cavity is provided with a gas outlet 1.10, and the gas inlet 1.9 and the gas outlet 1.10 are in communication with the reaction cavity, and the gas supply system can provide gas (such as protective gas, reaction gas, etc.) into the reaction cavity through the gas inlet 1.9. Along the direction from the gas inlet 1.9 to the gas outlet 1.10, the reaction cavity includes a weighing cavity, a gas preheating cavity and a sample placing cavity arranged in sequence, the weighing cavity can be provided with a weighing element 3.1, the sample placing cavity can be placed with a sample 3.6, and the weighing element 3.1 can weigh the sample 3.6 to monitor the weight of the sample 3.6 in real time during the reaction process. The gas preheating cavity is provided with a preheating element 2.2, and the preheating element 2.2 can heat the gas flowing through the gas preheating cavity to heat the sample 3.6 in the sample placing cavity by using the heated gas.

[0023] The electric furnace 2.7 is arranged outside the reaction container and is movable, and when the electric furnace 2.7 is needed to heat the sample 3.6, the electric furnace 2.7 can be moved to a first position where the sample placing cavity is located, so as to heat the sample 3.6 in the sample placing cavity by using the electric furnace 2.7; when the electric furnace 2.7 is not needed to heat the sample 3.6, the electric furnace 2.7 can be moved to a second position, at this time, the electric furnace 2.7 is located on the side of the sample placing cavity away from the gas preheating cavity, so that the electric furnace 2.7 is arranged in dislocation with the sample 3.6 in the sample placing cavity, so that the electric furnace 2.7 no longer heats the sample 3.6 in the sample placing cavity.

[0024] Compared with some thermal gravimetric analysis devices that gas is introduced from the upper and lower sides of the reaction container and gas is discharged from the middle of the reaction container, the thermal gravimetric analysis device of the embodiment of the application adopts an innovative gas path structure optimization design, gas can be introduced from one side of the reaction container and discharged from the other side of the reaction container, so that the gas flows in one direction in the reaction container. Therefore, the thermal gravimetric analysis device of the embodiment of the application realizes directional transmission of the gas by constructing a one-way closed flow channel, which can provide a stable gas atmosphere for the reaction of the sample 3.6 on the one hand, and is also conducive to improving the accuracy of the measurement of the tail gas composition on the other hand. In addition, based on the combination of a lower gas flow and a larger inner diameter of the reaction container design, the linear velocity of the gas flow in the reaction chamber can be controlled in a more optimal range of 0.05-0.2 m / s. This flow state conforms to the fluid mechanics characteristics (Peclet number Pe>100) of the plug flow reactor, which is characterized by: 1) uniform radial velocity distribution without turbulent vortex; 2) axial diffusion coefficient tends to zero. This technical solution can ensure that the gas in the reaction chamber realizes one-way plug flow, effectively suppresses the component concentration fluctuation caused by the back mixing phenomenon in the traditional gas path design, reduces the gas signal measurement error to below ±0.5% (relative standard deviation), and thus ensures the time domain stability and value traceability of the detection data.

[0025] In some example embodiments, as shown in Figure 1 and Figure 2 , the gas inlet 1.9 is arranged on the upper side of the reaction chamber, and the gas outlet 1.10 is arranged on the lower side of the reaction chamber, so that the gas can flow in one direction from the upper side to the lower side in the reaction chamber.

[0026] Of course, the gas inlet 1.9 can also be arranged on the lower side of the reaction chamber, and the gas outlet 1.10 can be arranged on the upper side of the reaction chamber, so that the gas can flow in one direction from the lower side to the upper side in the reaction chamber.

[0027] In some example embodiments, as shown in Figure 3a and Figure 3b , the sample container 3.5 includes a mesh container with an open upper end, and the sample 3.6 can be placed into the mesh container from the open upper end. For example, the sample container 3.5 can be a metal basket.

[0028] The sample container 3.5 is arranged in a mesh shape to facilitate the smooth flow of gas through the sample container 3.5 and the convection heat exchange between the gas and the sample 3.6, thereby providing a larger contact area for the gas-solid reaction and facilitating the radiation heat exchange between the electric furnace 2.7 and the sample 3.6.

[0029] In other example embodiments, as shown in Figures 3c-3f , the sample container 3.5 includes a mesh container with an open upper end and a baffle 3.51 arranged on the side of the mesh container, and the baffle 3.51 at least partially blocks the side of the mesh container. For example, Figure 3c and Figure 3dAs shown, the baffles 3.51 are in the form of vertically arranged strips, and a plurality of baffles 3.51 are arranged along the circumference of the mesh container; or, as shown, the baffles 3.51 are in the form of a ring and arranged around the side of the mesh container. Figure 3e and Figure 3f As shown, the baffles 3.51 are in the form of a ring and arranged around the side of the mesh container.

[0030] By using the baffles 3.51 to shield at least part of the side of the mesh container, the area of the side of the mesh container that is shielded can be set to 0-100% as required, such as 50% or other proportions. The baffles 3.51 can be arranged to be detachably fixed to the mesh container so as to adjust the shielding area of the baffles 3.51.

[0031] By arranging the baffles 3.51 on the side of the mesh container, the radiation heat exchange between the electric furnace 2.7 and the sample 3.6 can be slowed down so as to achieve different heating rates of the sample 3.6 and meet different heating working conditions.

[0032] In some exemplary embodiments, as shown in Figure 1 – Figure 2 , Figure 4a – Figure 4f As shown, the heating system further comprises an openable and closable heat shield 2.6, which is arranged on the side of the sample placement cavity away from the gas preheating cavity, and the electric furnace 2.7 in the second position is located on the side of the heat shield 2.6 away from the sample placement cavity. The heat shield 2.6 is arranged to be able to close to isolate the sample placement cavity from the electric furnace 2.7 in the second position, and the heat shield 2.6 is also arranged to be able to open so that the electric furnace 2.7 can heat the sample 3.6 in the sample placement cavity during the movement from the second position to the first position.

[0033] The openable and closable heat shield 2.6 has a closed state and an open state. When the sample 3.6 in the sample placement cavity does not need to be heated by the electric furnace 2.7, the electric furnace 2.7 can be in the second position and the heat shield 2.6 can be in the closed state, at this time the heat shield 2.6 is between the sample 3.6 in the sample placement cavity and the electric furnace 2.7 to isolate the sample 3.6 from the electric furnace 2.7 and prevent the electric furnace 2.7 from radiating heating the sample 3.6. When the sample 3.6 in the sample placement cavity needs to be heated by the electric furnace 2.7 and the gas, the heat shield 2.6 can be in the open state and the electric furnace 2.7 can be moved from the second position to the first position, and since the heat shield 2.6 has been opened, the electric furnace 2.7 can radiate heat the sample 3.6 during the movement.

[0034] In some exemplary embodiments, as shown in Figure 4a – Figure 4f As shown, the heat shield 2.6 comprises a base 2.61, a plurality of blades 2.63, a plurality of connecting rods 2.64 and a driving member 2.65.

[0035] The base 2.61 has a central hole 2.62; a plurality of blades 2.63 are arranged in sequence along the circumference of the central hole 2.62, and one end of each of the plurality of blades 2.63 is rotationally connected to the base 2.61; a plurality of connecting rods 2.64 correspond to the plurality of blades 2.63 one by one, and one end of each of the plurality of connecting rods 2.64 is rotationally connected to the corresponding blade 2.63, and the other end of each of the plurality of connecting rods 2.64 is rotationally connected to the driving member 2.65.

[0036] The driving member 2.65 is arranged to be rotatable about the axis of the central hole 2.62, and drives the plurality of blades 2.63 to swing through the plurality of connecting rods 2.64, so as to close or open the central hole 2.62.

[0037] In the heat blocking plate 2.6, the base 2.61 is provided with a central hole 2.62 which can be used for gas to pass through; a plurality of blades 2.63 are arranged in sequence along the circumference of the central hole 2.62 and are rotationally connected to the base 2.61; and the driving member 2.65 is connected to the plurality of blades 2.63 through the plurality of connecting rods 2.64. The driving member 2.65 is rotatable to drive the plurality of blades 2.63 to swing, so that the plurality of blades 2.63 can cooperate to close the central hole 2.62 of the base 2.61, at this time the heat blocking plate 2.6 is in a closed state; the driving member 2.65 can also be reversely rotated, so that the plurality of blades 2.63 can open the central hole 2.62 of the base 2.61, at this time the heat blocking plate 2.6 is in an open state.

[0038] In the embodiments of the present application, the opening and closing of the heat blocking plate 2.6 is mainly to isolate the high-temperature electric furnace 2.7 in the second position and the radiation heat exchange between the sample. The heat blocking plate 2.6 can pass gas in both open and closed states (for example, the plurality of blades 2.63 of the heat blocking plate 2.6 in the closed state, the gaps between the blades 2.63 and the central hole 2.62 of the base 2.61, etc. have a gap through which gas can pass), so as not to affect the circulation of the gas.

[0039] In some exemplary embodiments, as shown in Figure 4a Figure 4f The driving member 2.65 and one of the base 2.61 are provided with an arc-shaped sliding groove 2.66, and the other is provided with a sliding column 2.67, the sliding column 2.67 extends into the sliding groove 2.66 and can slide in the sliding groove 2.66. Among them, the base 2.61 can be provided with a plurality of sliding columns 2.67, and the plurality of sliding columns 2.67 can be uniformly arranged along the circumference of the base 2.61; the driving member 2.65 can be annular and provided with a plurality of sliding grooves 2.66, and the plurality of sliding columns 2.67 correspond to the plurality of sliding grooves 2.66 one by one, and the central axis of the driving member 2.65, the central axis of the base 2.61 and the central axis of the central hole 2.62 coincide.

[0040] ​The sliding column 2.67 is in sliding fit with the sliding groove 2.66, so that the driving member 2.65 can rotate around the axis of the central hole 2.62, so as to open or close the central hole 2.62 of the heat baffle 2.6.

[0041] In some example embodiments, as shown in Figure 1 and Figure 2 The gas preheating assembly further comprises an induction heating power supply 2.3, an induction coil 2.1 and a preheating temperature control element 2.4.

[0042] The induction coil 2.1 is wound outside the gas preheating cavity, the preheating element 2.2 comprises a heating wire, the induction heating power supply 2.3 is configured to provide alternating current to the induction coil 2.1, so that electromagnetic induction can be generated between the induction coil 2.1 and the heating wire, so that the heating wire generates heat; the preheating temperature control element 2.4 is configured to detect the temperature of the heating wire. The heating wire can be a platinum wire, and the preheating temperature control element 2.4 can be a preheating temperature control thermocouple.

[0043] In the gas preheating assembly, the induction heating power supply 2.3 is used to provide alternating current to the induction coil 2.1, and the induction coil 2.1 can generate an induction magnetic field after being connected to high-frequency alternating current. The heating wire generates eddy current in the induction magnetic field and starts to rapidly heat up. The gas entering the reaction cavity rapidly rises in temperature through convective heat exchange with the heating wire. The preheating temperature control thermocouple can collect the temperature of the heating wire in real time and transmit it to a control device (such as a computer, etc.). The heating wire calculates the characteristics of the induction current in the next period by comparing the actual temperature of the heating wire with the set temperature, and sends relevant instructions to the induction heating power supply 2.3 to adjust the induction current, until the temperature of the heating wire reaches the set temperature and is maintained stable.

[0044] In some example embodiments, as shown in Figure 1 and Figure 2 The measurement system further comprises a temperature measuring element 3.4, a wireless signal transmitter 3.2 and a wireless signal receiver 3.10.

[0045] The temperature measuring element 3.4 is configured to measure the temperature of the sample 3.6; the wireless signal transmitter 3.2 is arranged in the reaction cavity and located between the preheating element 2.2 and the weighing element 3.1. The wireless signal transmitter 3.2 is electrically connected with the temperature measuring element 3.4 and is configured to receive the temperature signal measured by the temperature measuring element 3.4; the wireless signal receiver 3.10 is arranged outside the reaction container and is configured to receive the temperature signal transmitted by the wireless signal transmitter 3.2.

[0046] The measurement system comprises a weighing element 3.1, a wireless signal transmitter 3.2, a suspension wire 3.3, a temperature measuring element 3.4, a sample container 3.5, and a wireless signal receiver 3.10, etc., wherein the weighing element 3.1 can be an electronic balance, the sample container 3.5 can be a metal basket, the metal basket can be connected to the electronic balance through the suspension wire 3.3, the temperature measuring element 3.4 can be a temperature measuring thermocouple (for example, a K-type thermocouple), and the temperature measuring element 3.4 and the wireless signal transmitter 3.2 can be connected to the electronic balance, for example, can be arranged on the suspension wire 3.3 connected to the electronic balance. During the experiment, the electronic balance actually weighs the total mass of the suspension wire 3.3, the wireless signal transmitter 3.2, the temperature measuring element 3.4, the sample container 3.5, and the sample 3.6. During the experiment, the mass of each component weighed by the electronic balance does not change except for the experimental sample 3.6, so the mass of the sample 3.6 can be obtained in real time by subtracting the fixed mass excluding the sample 3.6 from the total mass weighed by the electronic balance. The electronic balance transmits the mass signal to the control device (for example, a computer) through the data line for recording and saving. The measurement system uses multiple temperature measuring elements 3.4 (for example, three K-type thermocouples) to directly measure the temperature at different positions of the sample 3.6, so as to more comprehensively reflect the temperature rising process of the sample 3.6. Before the experiment, the sample 3.6 can be drilled (for example, drilled to different depths of the sample 3.6) to facilitate the installation of the temperature measuring element 3.4. The wireless signal transmitter 3.2 is responsible for receiving the temperature signal from the temperature measuring element 3.4 and wirelessly sending it to the wireless signal receiver 3.10, and the wireless signal receiver 3.10 transmits the final temperature signal to the control device (for example, a computer) for recording and saving. In the measurement system, the wireless temperature measuring device (including the temperature measuring element 3.4 and the wireless signal transmitter 3.2) responsible for measuring the temperature, the suspension wire 3.3, the sample container 3.5, and the sample 3.6 as a whole have no direct connection with the outside, which ensures the stability of the mass weighing of the electronic balance. At present, some thermal gravimetric analysis devices use wired thermocouples for temperature measurement, and if a wired thermocouple is used to directly measure the temperature of the sample 3.6, the wired connection of the thermocouple with the outside will usually affect the stability of the mass weighing. The thermal gravimetric analysis device of the embodiment of the present application introduces a wireless temperature measuring device, which effectively realizes direct temperature measurement while avoiding the influence of the wired connection of the temperature measuring device on the mass weighing.

[0047] In some example embodiments, as shown in Figure 1 and Figure 2 The measurement system further comprises at least one of an image acquisition device, a gas analysis device 3.12, and a heat tracing band 2.8.

[0048] An image acquisition device is installed to the electric furnace 2.7, and the electric furnace 2.7 is provided with an observation window 3.7, and the image acquisition device is arranged to be able to acquire the image of the sample 3.6 through the observation window 3.7 to obtain the topographic information (such as size information, etc.) and / or surface temperature information of the sample 3.6. Wherein, the image acquisition device can include a high-speed camera 3.8 and an infrared camera 3.9, and when the electric furnace 2.7 moves to the first position, the opened observation window 3.7 on the electric furnace 2.7 can be at the same horizontal position as the sample 3.6, and the high-speed camera 3.8 and the infrared camera 3.9 can be used to take real-time pictures of the sample 3.6 through the observation window 3.7.

[0049] The high-speed camera 3.8 can always obtain clear sample imaging. When calculating the size change of the sample during the experiment by using the image information acquired by the high-speed camera 3.8, the image processing software is used to automatically draw the outer contour of the sample 3.6 and calculate the pixel area within the contour of the sample 3.6; then, by comparing the size of the sample 3.6 at the initial moment, the size of the sample 3.6 at different moments of the experiment is calculated through the square relationship between the contour area of the sample 3.6 and the equivalent diameter of the sample 3.6.

[0050] The infrared camera 3.9 can measure the temperature of different points on the surface of the sample 3.6, or measure the average temperature of the surface of the sample 3.6.

[0051] The gas analysis device 3.12 is communicated with the gas outlet 1.10, and the gas analysis device 3.12 is arranged to be able to analyze the composition of the gas discharged from the gas outlet 1.10. Wherein, the gas analysis device 3.12 can be communicated to the gas outlet 1.10 through a capillary 3.11. The gas analysis device 3.12 can be a gas chromatograph mass spectrometer or a gas chromatograph gas analyzer, etc., and the gas analysis device 3.12 can analyze the composition of the gas discharged from the gas outlet 1.10 of the reaction container in real time to obtain more comprehensive experimental data.

[0052] The heat tracing band 2.8 is arranged on the side of the reaction chamber close to the gas outlet 1.10, and is arranged to be able to heat the gas in the reaction chamber to prevent some reaction products from condensing.

[0053] The products of the sample 3.6 after reaction can have components such as tar and water vapor, etc., and if there is no heating by the heat tracing band 2.8, the components such as tar and water vapor, etc. can condense at the position close to the gas outlet 1.10, which can affect the exhaust of the gas outlet 1.10 or cause the gas outlet 1.10 to be blocked, and also affect the detection of the composition of the gas discharged from the gas outlet 1.10. By arranging the heat tracing band 2.8, the gas can be heated again to avoid the components such as tar and water vapor, etc. from condensing before entering the gas analysis device 3.12, which can affect the measurement accuracy, so that the exhaust of the gas outlet 1.10 is smooth, and the detection of the composition of the gas discharged from the gas outlet 1.10 is more accurate.

[0054] In some exemplary embodiments, Figure 1 and Figure 2 As shown, the air supply system includes an air intake pipeline 1.5, an aerator 1.4, a flow detection unit 1.2 and a control valve 1.3.

[0055] The air intake pipeline 1.5 includes an air intake main circuit and multiple air intake branches. One end of the multiple air intake branches is configured to be connected to an air supply source (such as a gas cylinder 1.1, etc.), and one end of the air intake main circuit is connected to the air inlet 1.9; the aerator 1.4 has multiple air inlet holes and air outlet holes. The multiple air inlet holes are connected to the other ends of the multiple air intake branches in a one-to-one correspondence, and the air outlet holes are connected to the other end of the air intake main circuit. The aerator 1.4 can fully mix the gases from different air intake branches; the flow detection unit 1.2 is arranged on the air intake branch, and the flow detection unit 1.2 can be an electromagnetic flowmeter; the control valve 1.3 is arranged on the air intake branch, and is configured to control the air intake volume of the air intake branch. The control valve 1.3 can be an electromagnetic valve. By adjusting the opening of the electromagnetic valve, the air intake volume of the air intake branch can be controlled.

[0056] The gas supply system may include a gas cylinder 1.1, an inlet pipe 1.5, a control valve 1.3, a flow detection unit 1.2, and an aerator 1.4. The gas supply system's primary function is to regulate the composition and flow rate of the incoming gas into the reaction chamber. The number of gas cylinders 1.1 and inlet branches can be adjusted based on specific reaction requirements.

[0057] In some exemplary embodiments, the reaction vessel includes a reaction tube 1.7 and a sealing cover 1.6. One end of the reaction tube 1.7 is open, and the sealing cover 1.6 can be placed over the open end of the reaction tube 1.7. The sealing cover 1.6 and the reaction tube 1.7 are sealed together to ensure the sealing of the reaction chamber. The sealing cover 1.6 is provided with an air inlet 1.9, and an air outlet 1.10 is provided on the side of the reaction tube 1.7 away from the sealing cover 1.6. An exhaust line 1.8 is connected to the air outlet 1.10. The reaction tube 1.7 can be a quartz reaction tube 1.7.

[0058] The following describes in detail the thermogravimetric analysis device according to the embodiment of the present application with reference to the accompanying drawings.

[0059] The thermogravimetric analysis device mainly includes a gas supply system, a heating system, a measuring system and a reaction vessel.

[0060] The gas supply system primarily comprises a gas cylinder 1.1, an air inlet line 1.5, a control valve 1.3, and a flow detection unit 1.2. The reaction vessel primarily comprises a reaction tube 1.7 and a sealing cover 1.6. Flow detection unit 1.2 can be an electromagnetic flowmeter, capable of regulating the flow rate of a single air inlet branch within a range of 0–10 L / min. Sealing cover 1.6 can be a 3 mm thick steel metal cover. Reaction tube 1.7 can be a cylindrical quartz tube with an outer diameter of 84 mm and an inner diameter of 80 mm.

[0061] In the experiment, the gas is supplied by gas cylinder 1.1, sequentially passes through flow detection unit 1.2, control valve 1.3 and gas mixer 1.4, enters sealed cover 1.6 through gas inlet pipeline 1.5. Among them, control valve 1.3 can be a solenoid valve, which is used to switch between the protective gas before and after the start of the experiment and the experimental gas, so as to ensure the rapid switching of the gas at the start of the experiment. Flow detection unit 1.2 can be an electromagnetic flowmeter, which can adjust the flow of gas into the reaction chamber during the experiment. Flow detection unit 1.2 cooperates with control valve 1.3 to accurately control the composition and flow of the gas entering the reaction chamber of the reaction container, and gas mixer 1.4 can ensure that the incoming gas is fully mixed. The thermogravimetric analysis device uses flow detection unit 1.2, control valve 1.3 and gas mixer 1.4 in cooperation, on the one hand, to ensure the rapid response when switching from the protective gas to the reaction gas during the experiment; on the other hand, to also ensure that the gas entering the reaction chamber is fully mixed, uniform and stable in composition.

[0062] After the gas leaves gas inlet pipeline 1.5, it enters sealed cover 1.6. Sealed cover 1.6 provides space for the placement of the weighing element 3.1 (such as an electronic balance) of the measurement system, and also ensures the sealing of the reaction chamber. Subsequently, the gas flows from the top to the bottom of sealed cover 1.6 into reaction tube 1.7, and then flows through sample 3.6; finally, the gas is discharged from the experimental device through exhaust pipeline 1.8 at gas outlet 1.10, and is discharged into the atmosphere after purification.

[0063] The heating system mainly includes induction coil 2.1, preheating element 2.2, induction heating power supply 2.3, preheating temperature control element 2.4, electric furnace 2.7 guide rail, heat shield 2.6, electric furnace 2.7 and heating tape 2.8. Among them, preheating element 2.2 can be a heating wire (such as a platinum wire), the diameter of which can be 1.5 mm, filled in the gas preheating cavity of reaction tube 1.7, with a space in the middle for the passage of suspension wire 3.3 and temperature measuring element 3.4. Preheating temperature control element 2.4 can be a preheating temperature control thermocouple. Electric furnace 2.7 guide rail is arranged in the reaction container, and electric furnace 2.7 can move up and down along electric furnace 2.7 guide rail to switch between the first position and the second position. The rated power of induction heating power supply 2.3 can be 100 kW, and it can adjust the current and frequency of induction coil 2.1 in real time according to the preset heating program of the heating wire.

[0064] The structure of heat shield 2.6 is shown in Figure 4a – Figure 4f The structure of heat shield 2.6 in the closed state is shown in Figure 4a – Figure 4b The structure of heat shield 2.6 in the half-open state is shown in Figure 4c – Figure 4d The structure of heat shield 2.6 in the half-open state is shown in Figure 4e –Figure 4f The structural schematic diagram of the heat shield 2.6 in the fully open state is shown. The heat shield 2.6 is structured to ensure that the heat shield 2.6 can be opened and closed while saving space, so that the heat shield 2.6 can be quickly switched from the closed state to the open state after the experiment starts; on the other hand, it saves space and avoids possible interference (possible interference between the heat shield 2.6 and the electric furnace 2.7) during the lifting process of the electric furnace 2.7.

[0065] The main body of the sample container 3.5 for containing the sample 3.6 is a mesh container, which can be a mesh metal basket with a diameter of 60 mm and a height of 50 mm. In different temperature rise rate experiments, the shielding ratio of the side of the mesh container can be adjusted according to the needs, and the temperature rise rate of the sample 3.6 is adjusted by adjusting the intensity of the thermal radiation received by the sample 3.6. To achieve different temperature rise rates, the mesh container side can be unshielded (such as shown in Figure 3a Figure 3b ), the mesh container side can be half-shielded (such as shown in Figure 3c Figure 3d ), and the mesh container side can be fully shielded (such as shown in Figure 3e Figure 3f ). Among them, the form of the mesh container side without shielding can be applicable to slow and fast temperature rise conditions, and the forms of the mesh container side half-shielded and the mesh container side fully shielded can be applicable to medium temperature rise conditions.

[0066] The gas entering the reaction tube 1.7 first passes through the heating wire, then flows through the sample 3.6, and finally exits the reaction chamber through the gas outlet 1.10 and the exhaust pipe from the bottom of the reaction tube 1.7.

[0067] The main function of the heating system is to achieve slow, medium and fast temperature rise of the sample 3.6 during the experiment, especially to achieve the fast temperature rise condition which is difficult to achieve by the current thermal gravimetric analysis device.

[0068] ​​​The realization of the rapid heating condition relies on the electromagnetic induction of the heating wire to rapidly heat the preheating gas and the rapid upward movement of the high-temperature electric furnace 2.7 to the sample 3.6 (at the first position) to heat the sample 3.6. Before the experiment, the induction heating power supply 2.3 controls the induction coil 2.1 to be not powered on, the heating wire does not occur electromagnetic induction and the temperature is at room temperature. The electric furnace 2.7 is at the low position (second position) and is heated to the first target temperature (high target temperature) required by the experiment, and the heat shield 2.6 is closed to ensure that the sample 3.6 is always at room temperature and is not affected by the heat radiation of the high-temperature electric furnace 2.7. After the experiment starts, the control device (such as a computer) sends a signal to the induction heating power supply 2.3, and the induction heating power supply 2.3 provides high-frequency alternating current to the induction coil 2.1. Under the action of electromagnetic induction, the temperature of the heating wire rises rapidly, and the reaction gas flowing through it is preheated. The preheating temperature control element 2.4 returns the temperature of the heating wire in real time, and then the induction heating power supply 2.3 adjusts the induction current parameters in combination with the set temperature rising rate and the current temperature of the heating wire. After the heating wire rises to the target temperature, the induction heating power supply 2.3 adjusts the induction current parameters again to ensure that the temperature of the heating wire is constant. The heating wire can rise at a rate of up to 2000 K / min, and the temperature can be as high as 1000°C. At the same time, the heat shield 2.6 is opened, and the electric furnace 2.7, which has been heated to the first target temperature before the experiment, rises rapidly (such as within 30 s) from the second position (low position) in Figure 1 to the first position (high position) in Figure 2 to ensure that the electric furnace 2.7 and the sample 3.6 are at the same horizontal position. After the experiment starts, on the one hand, the temperature of the heating wire rises rapidly to the target temperature, and after the gas flowing through the heating wire is preheated to the target temperature, the gas flowing through the sample 3.6 exchanges heat with the sample 3.6 to heat the sample 3.6; on the other hand, the high-temperature electric furnace 2.7 rapidly rises to the same horizontal position as the sample 3.6 and exchanges heat with the sample 3.6. Under the combined action of the convective heat exchange from the preheated gas and the radiative heat exchange of the high-temperature electric furnace 2.7, the temperature of the sample 3.6 rises rapidly, and finally the rapid heating condition is realized. The sample 3.6 can rise at a rate of up to 1000 K / min.

[0069] Optionally, the thermal gravimetric analysis device can realize the slow uniform heating condition of the sample 3.6. In the slow heating condition, the electric furnace 2.7 is raised to the same level as the sample 3.6 before the experiment starts and the temperature is kept at room temperature. After the experiment starts, on the one hand, the inductive heating power supply 2.3 supplies high-frequency alternating current to the induction coil 2.1, and the heating wire rises in temperature at a uniform rate according to the set heating rate under the action of electromagnetic induction, and the incoming gas is preheated when passing through the heating wire; on the other hand, the electric furnace 2.7 rises in temperature at a uniform rate according to the set heating rate under program control. Under the combined action of preheated gas and the rising electric furnace 2.7, the temperature of the sample 3.6 basically rises at a uniform rate. In the slow heating condition, the highest heating rate of the sample 3.6 can be 40 K / min.

[0070] Optionally, the thermal gravimetric analysis device can realize the medium-speed heating condition of the sample 3.6. The main experimental steps in the medium-speed heating condition are basically the same as those in the fast heating condition. By setting different target temperatures of the heating wire and the electric furnace 2.7, and cooperating with the selection of a mesh container with a half-shielded or fully-shielded side to hold the sample 3.6, different heating rates can be realized. Test results show that when the target temperature is set to 900 °C and the mesh container with a half-shielded side is selected, the average heating rate of the sample 3.6 before reaching the target temperature can reach about 600 K / min; when the target temperature is set to 900 °C and the mesh container with a fully-shielded side is selected, the average heating rate of the sample 3.6 can reach about 300 K / min.

[0071] The heating system of the thermal gravimetric analysis device of the embodiment of the present application simulates the temperature rising condition experienced by the sample 3.6 in the actual industrial reaction process, and realizes the rapid temperature rising of the sample 3.6 through the combined action of heat convection and heat radiation. By adjusting the working process of the heating system, medium-speed and slow-speed temperature rising heating of the sample 3.6 can also be provided. In the rapid temperature rising mode, the preheating of the incoming gas and the rising of the high-temperature furnace 2.7 heated to the target temperature are carried out at the same time. After the experiment starts, the induction coil 2.1 is connected to the high-frequency alternating current, the heating wire generates eddy current in the induction magnetic field and starts to rapidly rise in temperature, and the gas entering the reaction tube 1.7 realizes rapid temperature rising through the heat convection between the heating wire. The preheating temperature control element 2.4 collects the temperature of the heating wire in real time and transmits it to the control device (such as a computer), the control device calculates the induction current characteristics of the next period by comparing the actual temperature of the heating wire with the set temperature, and sends relevant instructions to the induction heating power supply 2.3 to adjust the induction current until the temperature of the heating wire reaches the set temperature and maintains stable. Before the experiment starts, the furnace 2.7 located at the bottom of the guide rail (the second position) has been heated to the first target temperature. The heat shield 2.6 below the sample 3.6 is in the closed state to prevent the heating of the sample 3.6 from the radiation of the high-temperature furnace 2.7. After the experiment starts, the heat shield 2.6 below the sample 3.6 is opened while the induction coil 2.1 is connected to the high-frequency induction current, and the furnace 2.7 rises to the same horizontal position as the sample 3.6 (the first position) along the guide rail. The heat convection between the high-temperature heating wire preheating and the sample 3.6 and the radiation heat transfer from the high-temperature furnace 2.7 realize the rapid temperature rising of the sample 3.6 by simulating the heating process of the sample 3.6 in the actual production.

[0072] The heating system can also provide medium-speed and slow-speed temperature rising heating of the sample 3.6. When the medium-speed temperature rising experiment is carried out, the implementation mode of the temperature rising of the sample 3.6 is similar to that of the rapid temperature rising mode, and the main difference is that when the medium-speed temperature rising is realized, the side of the mesh container loaded with the sample 3.6 is partially or completely shielded to weaken the radiation heat transfer, and the corresponding medium-speed temperature rising of the heating wire is realized, finally realizing the medium-speed temperature rising of 300-700 K / min.

[0073] The slow-speed temperature rising is realized in a different way from the rapid and medium-speed temperature rising. When the slow-speed temperature rising experiment is carried out, the furnace 2.7 is at the same horizontal height as the sample 3.6 before the experiment starts (the furnace 2.7 is at the first position). After the experiment starts, the heating wire and the furnace 2.7 both rise at a uniform speed according to the set temperature rising rate to realize the slow-speed uniform temperature rising of the sample 3.6, and the temperature rising rate of the sample 3.6 remains constant during the whole experiment.

[0074] The measurement system mainly includes a weighing element 3.1, a wireless signal transmitter 3.2, a suspension wire 3.3, a temperature measuring element 3.4, a sample container 3.5, an observation window 3.7, a high-speed camera 3.8, an infrared camera 3.9, a wireless signal receiver 3.10, a capillary tube 3.11, a gas analysis device 3.12, etc. The weighing element 3.1 can be an electronic balance, which can have a range of 0-1200 g, a measurement accuracy of ±1 mg, and a measurement frequency of 0.5 s per measurement point. The temperature measuring element 3.4 can be a K-type thermocouple, which can have a diameter of 0.5 mm, a temperature measuring range of 0-1300 °C in cooperation with the wireless signal transmitter 3.2 and the wireless signal receiver 3.10, a temperature measuring accuracy of ±1 K, and a sampling frequency of 1 s per sampling. When drilling the sample 3.6, a 0.75 mm drill bit can be used to drill to the set measurement point, avoiding excessive impact on the appearance of the sample 3.6. Each K-type thermocouple is inserted into the drilled hole of the sample 3.6 for direct temperature measurement. Experimental test results show that under the same experimental conditions, the sample 3.6 mass change characteristic curves of the sample 3.6 without drilling and the sample 3.6 with drilling are basically the same. This indicates that the drilling of the sample 3.6 has little effect on the mass loss characteristics of the sample 3.6 during the thermochemical conversion process.

[0075] The high-speed camera 3.8 can have a pixel of 24 million, and can record up to 240 frames per second. The focal length of the high-speed camera 3.8 can be manually adjusted. Before the experiment starts, the focal length is adjusted according to the distance between the lens of the high-speed camera 3.8 and the sample 3.6 to ensure clear imaging of the sample 3.6. The aperture of the high-speed camera 3.8 can be automatically adjusted. When the temperature of the electric furnace 2.7 is low, the background radiation is low, and at this time the aperture is large to ensure sufficient light quantity and finally clear imaging; when the temperature of the electric furnace 2.7 is high, the background radiation is strong, and at this time the aperture is automatically adjusted to realize clear imaging of the sample 3.6. Before the experiment starts, after adjusting the lens focal length to achieve clear imaging of the sample 3.6, the lens position and focal length will not be adjusted during the entire experiment to ensure that clear imaging of the sample 3.6 can be obtained at all times. When calculating the size change of the sample 3.6 during the experiment using image information, an image processing software is used to automatically draw the outer contour of the sample 3.6 and calculate the pixel area within the contour of the sample 3.6; then, by comparing the size of the sample 3.6 at the initial time, the size of the sample 3.6 at different times during the experiment is calculated.

[0076] The pixel of the infrared camera 3.9 can be 2 million, and a maximum of 15 frames of pictures can be recorded per second, the temperature measurement range is 200-1400 °C, and the temperature measurement accuracy can be ± 15 K. The focal length of the infrared camera 3.9 can be manually adjusted, and the operation is basically the same as that of the high-speed camera 3.8. The infrared camera 3.9 can measure the temperature of different points on the surface of the sample 3.6, or the average temperature of the surface of the sample 3.6.

[0077] During the experiment, the actual weight measured by the weight measuring element 3.1 is the total mass of the hanging wire 3.3, the wireless signal transmitter 3.2, the temperature measuring element 3.4, the sample container 3.5 and the sample 3.6. During the experiment, the mass of each component measured by the weight measuring element 3.1 does not change except the experimental sample 3.6, so the mass of the sample 3.6 can be obtained in real time by subtracting the fixed mass excluding the sample 3.6 from the total mass. The weight measuring element 3.1 transmits the mass signal to the control device (such as a computer) through the data line for recording and saving. The measurement system uses three K-type thermocouples to directly measure the temperature at different positions of the sample 3.6 to more comprehensively reflect the sample 3.6 heating process. Before the experiment, the sample 3.6 needs to be drilled at different positions to facilitate the installation of the thermocouple. The wireless signal transmitter 3.2 is responsible for receiving the temperature signal from the K-type thermocouple and sending it wirelessly to the wireless signal receiver 3.10, and the wireless signal receiver 3.10 transmits the final temperature signal to the control device for recording and saving. In the measurement system, the temperature measuring element 3.4 and the wireless signal transmitter 3.2 responsible for measuring the temperature are connected to the hanging wire 3.3, the sample container 3.5 and the sample 3.6 as a whole, without direct connection to the outside, ensuring the stability of the mass measurement of the weight measuring element 3.1. Compared with directly measuring the temperature of the sample 3.6 using a wired thermocouple, the stability of the mass measurement is usually affected by the wired connection of the thermocouple to the outside. The present thermal analysis device introduces a wireless temperature measuring device (including a temperature measuring element 3.4 and a wireless signal transmitter 3.2) to measure the temperature, effectively achieving direct temperature measurement while avoiding the influence of wired connection of the thermocouple on mass measurement. During the experiment, as the electric furnace 2.7 rises to the top of the guide rail, the observation window 3.7 opened on the electric furnace 2.7 is at the same horizontal position as the sample 3.6 (first position), and the high-speed camera 3.8 and the infrared camera 3.9 can be used to take real-time pictures of the sample 3.6 through the observation window 3.7.

[0078] Further, by installing a gas analysis device 3.12 (such as a gas chromatograph or a gas chromatograph gas analyzer) at the gas outlet 1.10 of the reaction tube 1.7, the gas analysis device 3.12 and the gas outlet 1.10 can be connected through a capillary 3.11. By using the gas analysis device 3.12, the gas composition at the gas outlet 1.10 can be analyzed in real time to obtain more comprehensive experimental data.

[0079] The application also provides a control method of the thermal gravimetric analysis device. The gas supply system supplies gas into the reaction container, and the gas flows from the gas inlet to the gas outlet in a one-way manner and keeps a plug flow state. The preheating element of the heating system heats the gas entering the reaction container to heat the sample in the sample placement cavity by the heated gas, and the electric furnace of the heating system is moved to the first position where the sample placement cavity is located to heat the sample in the sample placement cavity by the electric furnace. The measurement system measures the parameter information of the sample.

[0080] When the thermal gravimetric analysis device is used for experiments, the gas supply system supplies gas into the reaction container, and the gas flows from the gas inlet 1.9 to the gas outlet 1.10 in a one-way manner in the reaction cavity of the reaction container, and the gas flow keeps a plug flow state, which effectively suppresses the fluctuation of the gas component concentration caused by the gas back mixing phenomenon, and is beneficial to reduce the error of the gas signal measurement, thereby ensuring the time domain stability and value traceability of the detection data.

[0081] When the sample 3.6 in the sample placement cavity is heated, the preheating element 2.2 of the heating system can be used to heat the gas entering the reaction container to heat the sample 3.6 by the heated gas in a convection manner, and the electric furnace 2.7 of the heating system can be moved to the first position where the sample placement cavity is located to heat the sample 3.6 in the sample placement cavity by the electric furnace 2.7 in a radiation manner.

[0082] During the experiment, the measurement system can also measure the parameter information (such as size, temperature, weight, etc.) of the sample 3.6 in real time and online.

[0083] In some example embodiments, the control method of the thermal gravimetric analysis device includes the step of controlling the gas supply system to supply gas to the reaction container, which includes: According to the detection result of the flow detection unit of the gas supply system, the opening degree of the control valve of the gas supply system is controlled to make the flow velocity of the gas in the reaction cavity of the reaction container be 0.05-0.2 m / s.

[0084] By controlling the gas supply system, a lower gas flow can be provided. By matching the lower gas flow with a larger inner diameter of the reaction container, the linear velocity of the gas flow in the reaction cavity can be controlled in the range of 0.05-0.2 m / s. The gas in this flow state meets the mechanical characteristics of the plug flow fluid, which can effectively suppress the fluctuation of the component concentration caused by the gas back mixing phenomenon, reduce the error of the gas signal measurement, and thereby ensure the time domain stability and value traceability of the detection data.

[0085] In some exemplary embodiments, the thermogravimetric analysis apparatus has a first heating condition, a second heating condition, and a third heating condition. The first heating condition may be a rapid heating condition for sample 3.6, the second heating condition may be a moderate heating condition for sample 3.6, and the third heating condition may be a slow heating condition for sample 3.6. The heating rate of sample 3.6 in the first heating condition is greater than the heating rate of sample 3.6 in the second heating condition, and the heating rate of sample 3.6 in the second heating condition is greater than the heating rate of sample 3.6 in the third heating condition.

[0086] In the control method of the thermogravimetric analysis device, the step of controlling the electric furnace of the heating system to move to the first position where the sample placement cavity is located so as to heat the sample in the sample placement cavity by using the electric furnace includes: Based on the thermogravimetric analyzer being in a first heating state, a mesh container without side baffles is used to hold the sample, and the electric furnace is controlled to heat up to a first target temperature, and then the electric furnace heated to the first target temperature is moved to a first position to heat the sample; Based on the thermogravimetric analyzer being in the second heating state, a mesh container having a side at least partially shielded by a baffle is used to hold the sample, and the electric furnace is controlled to heat to a second target temperature, and then the electric furnace heated to the second target temperature is moved to the first position to heat the sample; Based on the fact that the thermogravimetric analyzer is in the third heating condition, a mesh container without side baffles is used to hold the sample, and the electric furnace is controlled to move to the first position, and then the electric furnace is controlled to heat up to heat the sample.

[0087] Under the first heating condition, a mesh container without side baffles 3.51 is used to hold the sample 3.6, and before the electric furnace 2.7 is moved to the first position, the electric furnace 2.7 is first heated to the first target temperature, and then the electric furnace 2.7 is moved to the same horizontal position as the sample 3.6 to heat the sample 3.6 using the electric furnace 2.7; while the electric furnace 2.7 is moved, the preheating element 2.2 can heat and increase the temperature of the gas entering the reaction container, and use the gas to heat the sample 3.6, so as to simultaneously achieve radiation heating of the sample 3.6 by the electric furnace 2.7 and convection heating of the sample 3.6 by the gas.

[0088] The control steps of the second heating condition are basically the same as those of the first heating condition. The main difference is that, in the second heating condition, a mesh container whose sides are at least partially shielded by the baffle 3.51 is used to hold the sample 3.6 (the shielded area of ​​the side of the mesh container can be 0–100%), and before the electric furnace 2.7 is moved to the first position, the electric furnace 2.7 is controlled to heat up to a second target temperature, which can be less than or equal to the first target temperature.

[0089] In the third heating condition, the sample 3.6 is placed in the mesh container which is shielded by the side without baffle 3.51, and the electric furnace 2.7 is first moved to the first position, and then the electric furnace 2.7 (at room temperature) is moved to the same horizontal position as the sample 3.6, and then the temperature of the electric furnace 2.7 is controlled to heat the sample 3.6 by the electric furnace 2.7.

[0090] In some example embodiments, in the first heating condition, the sample 3.6 can have a heating rate greater than 1000 K / min; in the third heating condition, the sample 3.6 can have a heating rate of 5-120 K / min; and in the second heating condition, the sample 3.6 can have a heating rate of 300-700 K / min, such as about 500 K / min.

[0091] Of course, in the first heating condition, the second heating condition, and the third heating condition, the heating rate of the sample 3.6 is not limited to the above ranges, and can be adjusted according to actual needs.

[0092] In some example embodiments, the control method of the thermogravimetric analysis device further includes: Based on the thermogravimetric analysis device being in the first heating condition, the second heating condition, or the third heating condition, the heating rate of the preheating element is controlled according to the heating rate of the sample in the heating condition, and the actual heating rate of the sample is ensured to conform to the heating rate of the sample in the heating condition through the coordination of the electric furnace and the preheating element.

[0093] When the thermogravimetric analysis device is in different heating conditions such as the first heating condition, the second heating condition, or the third heating condition, the heating rate of the preheating element can be set according to the heating rate of the sample in the heating condition, to realize accurate control of the preheating temperature and the heating rate of the incoming gas, and the actual heating rate of the sample is ensured to conform to the heating rate of the sample in the heating condition through the coordination of the heating electric furnace and the preheating element.

[0094] The embodiments of the present application also provide a control device of a thermogravimetric analysis device, which includes a processor, a memory, and a computer program stored in the memory and executable on the processor, and the computer program, when executed by the processor, implements the steps of the control method in any of the above embodiments.

[0095] In summary, the embodiments of the present application provide a visual, fast heating, wide range, and high precision thermogravimetric analysis device, which can provide a fast heating (greater than 1000 K / min) condition for a large size solid sample 3.6, and can continuously and directly collect the temperature, mass, image signal, and gas component signal of the sample 3.6 during the experiment. Optionally, the device can also provide slow heating (5-120 K / min) and medium speed heating (300-700 K / min) conditions.

[0096] The thermal gravimetric analysis device of the embodiment has the following technical advantages: (1) On one hand, the gas is fully preheated, and the sample 3.6 is heated through the convective heat exchange between the incoming gas and the sample 3.6. On the other hand, the sample 3.6 is heated through the radiative heat exchange based on the movement of the high-temperature furnace 2.7, which together ensures the rapid heating of the sample 3.6.

[0097] (2) The heat shield 2.6 between the sample 3.6 and the furnace 2.7 prevents the radiative heat exchange between the high-temperature furnace 2.7 and the sample 3.6 before the experiment starts, so as to ensure that the sample 3.6 remains at room temperature before the experiment starts.

[0098] (3) The furnace 2.7 and the measurement components for measuring mass and temperature are relatively independent, which decouples the movement of the furnace 2.7 and the mass measurement, so as to avoid the influence of the vibration generated by the movement of the furnace 2.7 on the mass measurement.

[0099] (4) Through reasonable structural design, the one-way flow of the gas in the reaction tube 1.7 is ensured. Since the overall gas flow rate is relatively low, the gas flow in the reaction tube 1.7 basically maintains a laminar flow, which ensures that the gas signal can more accurately reflect the reaction progress of the sample 3.6.

[0100] (5) The high-speed camera 3.8 and the infrared camera 3.9 are used at the same time to record the real-time changes of the surface temperature and the morphology of the sample 3.6 during the reaction, so as to obtain more detailed information of the sample 3.6 during the reaction.

[0101] (6) The thermal chemical reaction of the large-size sample 3.6 can be provided with a wide experimental condition covering slow, medium and fast heating rates, and the mass, temperature and morphology of the sample 3.6 during the reaction can be directly measured, which provides more reliable and comprehensive data support for establishing the model of the thermal chemical conversion of the sample 3.6.

[0102] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0103] In addition, the terms "first", "second", etc. are used only for the purpose of description, and should not be understood as indicating or implying relative importance or an indicated number of technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features.

[0104] In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0105] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0106] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0107] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms is not necessarily for the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in the present application and the features of different embodiments or examples without contradiction.

[0108] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A thermogravimetric analysis device, characterized in that include: A reaction container having a reaction chamber, an air inlet disposed on one side of the reaction chamber, and an air outlet disposed on the other side of the reaction chamber, wherein the reaction chamber includes a weighing chamber, a gas preheating chamber, and a sample placement chamber disposed in sequence along a direction from the air inlet toward the air outlet; an air supply system, connected to the air inlet; a heating system comprising a movable electric furnace and a gas preheating assembly, wherein the gas preheating assembly comprises a preheating element disposed within the gas preheating chamber, the electric furnace being configured to be movable to a first position where the sample placement chamber is located to heat the sample within the sample placement chamber, and to be movable to a second position on a side of the sample placement chamber away from the gas preheating chamber to stop heating the sample; and The measuring system comprises a weighing element fixedly arranged in the weighing cavity and a sample container arranged in the sample placement cavity, wherein the weighing element is arranged to measure the weight of the sample in the sample container.

2. The thermogravimetric analysis device according to claim 1, characterized in that The air inlet is arranged at the upper side of the reaction chamber, and the air outlet is arranged at the lower side of the reaction chamber.

3. The thermogravimetric analysis device according to claim 1, characterized in that The sample container comprises a mesh container with an open upper end; or The sample container comprises a mesh container with an open upper end and a baffle arranged on a side of the mesh container, wherein the baffle at least partially blocks the side of the mesh container.

4. The thermogravimetric analysis device according to claim 3, characterized in that The baffle is in the shape of a vertical strip, and a plurality of the baffles are provided, and the plurality of the baffles are spaced apart along the circumference of the mesh container; or The baffle is annular and is arranged around the side of the mesh container.

5. The thermogravimetric analysis device according to claim 1, characterized in that The heating system further comprises: an openable and closable heat shield, disposed on a side of the sample placement chamber away from the gas preheating chamber, and the electric furnace in the second position is located on a side of the heat shield away from the sample placement chamber; The heat shield is configured to be closed to isolate the sample placement cavity from the electric furnace in the second position, and the heat shield is configured to be opened to allow the electric furnace to heat the sample during the process of moving from the second position to the first position.

6. The thermogravimetric analysis device according to claim 5, characterized in that The heat shield comprises: a base having a central hole; A plurality of blades are sequentially arranged along the circumference of the central hole, and one end of each blade is rotatably connected to the base; a plurality of connecting rods corresponding one to one with the plurality of blades, and one end of each of the connecting rods being rotatably connected to the corresponding blades; and a driving member, to which the other ends of the plurality of connecting rods are rotatably connected; The driving member is configured to rotate around the axis of the central hole and drive the plurality of blades to swing through the plurality of connecting rods to close or open the central hole.

7. The thermogravimetric analysis device according to claim 1, characterized in that The gas preheating assembly further comprises: Induction heating power supply; an induction coil wound around the outside of the gas preheating chamber, the preheating element comprising a heating wire, the induction heating power supply being configured to provide alternating current to the induction coil, thereby generating electromagnetic induction between the induction coil and the heating wire, thereby causing the heating wire to heat; and The preheating temperature control element is configured to detect the temperature of the heating wire.

8. The thermogravimetric analysis device according to any one of claims 1 to 7, characterized in that The measurement system further comprises: a temperature measuring element, configured to measure the temperature of the sample; a wireless signal transmitter disposed in the reaction chamber and between the preheating element and the weighing element, the wireless signal transmitter being electrically connected to the temperature measuring element and configured to receive a temperature signal measured by the temperature measuring element; and The wireless signal receiver is arranged outside the reaction container and is configured to receive the temperature signal transmitted by the wireless signal transmitter.

9. The thermogravimetric analysis device according to any one of claims 1 to 7, characterized in that The measurement system further comprises at least one of the following: an image acquisition device, mounted on the electric furnace, the electric furnace being provided with an observation window, the image acquisition device being configured to acquire an image of the sample through the observation window for obtaining morphological information and / or surface temperature information of the sample; a gas analysis device, connected to the gas outlet, and configured to analyze the composition of the gas discharged from the gas outlet; The heating tape is arranged on one side of the reaction chamber close to the gas outlet and is configured to heat the gas in the reaction chamber to prevent condensation of part of the reaction products.

10. The thermogravimetric analysis device according to any one of claims 1 to 7, characterized in that The gas supply system comprises: An air intake pipeline, comprising an air intake main line and a plurality of air intake branches, one end of each of the plurality of air intake branches being connected to an air supply source, and one end of the air intake main line being in communication with the air inlet; an aerator having a plurality of air inlets and air outlets, wherein the plurality of air inlets are connected to the other ends of the plurality of air inlet branches in a one-to-one correspondence, and the air outlets are connected to the other end of the air inlet main line; A flow detection unit is provided on the intake branch; and The control valve is arranged on the air intake branch and is configured to control the air intake amount of the air intake branch.

11. A method for controlling a thermogravimetric analysis device according to any one of claims 1 to 10, characterized in that: include: Controlling the gas supply system to supply gas into the reaction container so that the gas flows unidirectionally from the gas inlet to the gas outlet and maintains plug flow; controlling the preheating element of the heating system to heat the gas entering the reaction container so as to heat the sample in the sample placement cavity using the heated gas, and controlling the electric furnace of the heating system to move to the first position where the sample placement cavity is located so as to heat the sample in the sample placement cavity using the electric furnace; and The measuring system is controlled to measure parameter information of the sample.

12. The control method of the thermogravimetric analysis device according to claim 11, characterized in that: The controlling the gas supply system to supply gas to the reaction container comprises: According to the detection result of the flow detection unit of the gas supply system, the opening of the control valve of the gas supply system is controlled so that the flow velocity of the gas in the reaction chamber of the reaction container is 0.05-0.2 m / s.

13. The control method of the thermogravimetric analysis device according to claim 11 or 12, characterized in that: The thermogravimetric analysis device has a first heating condition, a second heating condition, and a third heating condition, wherein the temperature rise rate of the sample under the first heating condition is greater than the temperature rise rate of the sample under the second heating condition, and the temperature rise rate of the sample under the second heating condition is greater than the temperature rise rate of the sample under the third heating condition; The step of controlling the electric furnace of the heating system to move to a first position where the sample placement cavity is located, so as to heat the sample in the sample placement cavity by using the electric furnace, comprises: Based on the thermogravimetric analyzer being in the first heating state, the sample is placed in a mesh container without side baffles, the electric furnace is controlled to heat to a first target temperature, and the electric furnace heated to the first target temperature is moved to the first position to heat the sample; Based on the thermogravimetric analyzer being in the second heating state, the sample is placed in a mesh container whose sides are at least partially shielded by a baffle, the electric furnace is controlled to heat to a second target temperature, and then the electric furnace heated to the second target temperature is moved to the first position to heat the sample; Based on the fact that the thermogravimetric analyzer is in the third heating condition, a mesh container without side baffles is used to hold the sample, and the electric furnace is controlled to move to the first position, and then the electric furnace is controlled to heat up to heat the sample.

14. The control method of the thermogravimetric analysis device according to claim 13, characterized in that: Under the first heating condition, the heating rate of the sample is greater than 1000 K / min; Under the third heating condition, the sample heating rate is 5–120 K / min; Under the second heating condition, the sample heating rate was 300–700 K / min.

15. The control method of the thermogravimetric analysis device according to claim 13, characterized in that: Also includes: When the thermogravimetric analysis device is in the first heating condition, the second heating condition or the third heating condition, the heating rate of the preheating element is controlled according to the heating rate of the sample under the heating condition, and the actual heating rate of the sample is made to conform to the heating rate of the sample under the condition through the coordinated cooperation of the electric furnace and the preheating element.

16. A control device for a thermogravimetric analysis device, characterized in that: The method comprises a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the computer program implements the steps of the control method according to any one of claims 11 to 15 when executed by the processor.

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