Thermogravimetric analysis device and method for microwave-assisted carbon dioxide capture

Abstract

The invention provides a thermogravimetric analysis device and method for microwave-assisted carbon dioxide capture. The thermogravimetric analysis device comprises a gas conveying and switching unit, a microwave-assisted reaction unit, a temperature measuring unit, a weight recording unit and a gas analysis unit. According to the thermogravimetric analysis device, mass transfer and heat transfer are more sufficient, microwaves can act on samples in a concentrated mode, the adsorption and desorption efficiency is higher, and gas leakage and microwave leakage can be effectively avoided. According to the thermogravimetric analysis device, effective combination of a microwave heating system and a thermogravimetric analysis system is achieved, the adsorption and desorption capacity of a sample to carbon dioxide can be measured in real time, weight measurement data are more accurate, and the adsorption and desorption conditions of the carbon dioxide can be reflected more comprehensively and visually. The thermogravimetric analysis method for microwave-assisted carbon dioxide capture is carried out in the thermogravimetric analysis device, the method is high in repeatability, and the cyclic stability of adsorption-desorption of carbon dioxide is good.

Description

Technical Field The present invention belongs to the technical field of thermogravimetric analysis, and relates to a thermogravimetric analysis device and method for microwave-assisted carbon dioxide capture. Background Art Thermogravimetric analysis is an important method for studying the characteristics of materials and reaction laws. Traditional thermogravimetric analysis technology provides heat energy to reaction materials through electric heating, which belongs to an external heating method. Microwave heating has the advantages of fast heating rate, uniform heating, easy control, energy saving, safety and no pollution, and produces a temperature gradient opposite to that of traditional electric heating, which may cause a change in the reaction path. Most of the existing thermogravimetric analysis devices adopt the electric heating method and cannot realize the real-time measurement of the weight of samples in a microwave environment. The existing microwave thermogravimetric analysis device technology is not perfect. For example, the microwave thermogravimetric analysis device disclosed in CN108680458A still has the following problems: 1) The microwave distribution is uneven, the controllability of the heating area for repeated tests is poor, the random error is large, and there is a risk of microwave leakage; 2) The balance bracket extends into the reaction chamber, there is a slight air leakage phenomenon, and the air leakage prevention device has a complex and redundant structure; 3) The gas cannot fully contact the sample, and the heat and mass transfer effects are not good. Carbon capture technology is a technology that separates CO 2 from industrial emission sources or the atmosphere to reduce greenhouse gas emissions, and can play an important role in addressing global climate change and achieving the carbon neutrality goal. Thermogravimetric analysis can record the adsorption and regeneration processes of CO 2 in real time and accurately reflect the adsorption characteristics of materials. Microwave heating can reduce the energy consumption of CO 2 regeneration and increase the desorption rate of CO 2 , which is of great significance to the development of carbon capture technology. For example, CN109200749A discloses a temperature swing adsorption carbon capture system for microwave heating-assisted desorption process. This system uses microwave heating to desorb CO 2 , improving the desorption efficiency of CO 2 , but it does not monitor the adsorption / desorption data in real time, and this method cannot accurately and comprehensively reflect the adsorption / desorption status of CO 2 . Summary of the Invention Problems to be Solved by the Invention Aiming at the problems existing in the above technologies, the present invention aims to provide a thermogravimetric analysis device and method for microwave-assisted carbon dioxide capture. The thermogravimetric analysis device of the present invention can combine a microwave heating system and a thermogravimetric analysis system, and can measure the weight of a sample in real time under the action of a microwave field; the design of the fixed-bed reaction tube can improve the gas-solid heat and mass transfer effect, and the design that the balance is located outside the fixed-bed reaction tube can effectively avoid gas leakage; the design of single-mode microwave output, the annular microwave cavity and the circulator makes the microwave focus point fixed, and can also effectively avoid microwave leakage; the method has strong experimental repeatability and good cyclic stability of adsorption-desorption. Solutions for Solving the Problems To solve the above technical problems, the present invention provides the following technical solutions:

[0001] A thermogravimetric analysis device for microwave-assisted carbon dioxide capture, comprising: a gas delivery and switching unit, a microwave-assisted reaction unit, a temperature measurement unit, a weight recording unit and a gas analysis unit; The gas delivery and switching unit has a gas delivery structure and a gas mixing structure; The microwave-assisted reaction unit has a microwave generation structure, a waveguide, a circulator and a microwave cavity; the microwave generation structure generates microwaves, and the microwaves are conducted to the circulator through the waveguide, and then conducted to the microwave cavity after being processed by the circulator; The weight recording unit has a fixed-bed reaction tube, a weight measurement structure and a weight recording structure; the fixed-bed reaction tube is used to place the sample to be measured, the fixed-bed reaction tube passes through the microwave cavity, the side of the fixed-bed reaction tube is provided with an air inlet, one end of the fixed-bed reaction tube is connected to the weight measurement structure, and the other end is provided with an air outlet; The gas analysis unit is communicated with the air outlet of the fixed-bed reaction tube.

[0002] The thermogravimetric analysis device according to [1], wherein: The microwave-assisted reaction unit further has a water load and a circulation water tank; the circulation water tank is connected with a circulation water pipe, and the circulation water pipe is placed inside the waveguide and is connected with the microwave generation structure, the circulator, the microwave cavity and the water load.

[0003] The thermogravimetric analysis device according to [1] or [2], wherein: The microwave generation structure has a magnetron, a controller and a power supply, the controller controls the power supply, and the power supply controls the magnetron.

[0004] The thermogravimetric analysis device according to any one of [1]-[3], wherein: The weight measurement structure has a balance, a hanging wire and a flange; The fixed bed reaction tube is a quartz tube; A sieve plate is provided inside the fixed bed reaction tube, and the sample to be tested is placed on the sieve plate; One end of the fixed bed reaction tube is connected to the flange in the weight measurement structure. A hollow ring is provided on the upper part of the flange, and the hanging wire passes through the hollow ring and is connected to the balance.

[0005] The thermogravimetric analysis device according to any one of [1]-[4], wherein: The gas mixing structure has a gas distribution box. The gas outlet of the gas distribution box is communicated with the gas inlet of the fixed bed reaction tube, and a flow meter is built in; The gas analysis unit has a gas inlet, and the gas inlet of the gas analyzer is connected to the gas outlet of the fixed bed reaction tube; The temperature measurement unit has an infrared thermometer.

[0006] A thermogravimetric analysis method for microwave-assisted carbon dioxide capture, which is carried out in the thermogravimetric analysis device according to any one of [1]-[5], and includes the following steps: Step 1): Place the sample to be tested into the fixed bed reaction tube; Step 2): Make the microwave generating structure generate microwaves. The microwaves are conducted to the circulator through the waveguide, and then conducted to the microwave cavity after being processed by the circulator. The microwaves act on the sample to be tested through the fixed bed reaction tube; Step 3): Introduce a gas containing carbon dioxide from the gas inlet of the fixed bed reaction tube. The gas containing carbon dioxide flows through the sample to be tested, and the sample to be tested completes the adsorption of carbon dioxide; record the real-time weighing value of the weight measurement structure and the real-time temperature of the sample to be tested; Step 4): Introduce a gas from the gas inlet of the fixed bed reaction tube. The sample to be tested completes the desorption of carbon dioxide, and the desorbed gas is discharged through the gas outlet of the fixed bed reaction tube; record the real-time weighing value of the weight measurement structure and the real-time temperature of the sample to be tested.

[0007] The thermogravimetric analysis method according to [6], wherein: The sample to be tested is an adsorption-wave absorbing bifunctional material, and the adsorption-wave absorbing bifunctional material contains an adsorption component and a microwave absorption component; The adsorption component is molecular sieve, calcium oxide, lithium zirconate or lithium silicate; The microwave absorption component is silicon carbide, graphene, graphite, carbon fiber or carbon nanotube; The mass ratio of the adsorption component to the microwave absorption component is 1:0.5 - 1:2.

[0008] , The thermogravimetric analysis method according to [6] or [7], wherein: Set the microwave power and heating temperature in step 3); In step 3), the microwave power is set to 0 - 600 W, and the heating temperature is set to 15 - 650 °C.

[0009] , The thermogravimetric analysis method according to any one of [6] - [8], wherein: Set the microwave power and heating temperature in step 4); In step 4), the microwave power is set to 300 - 1000 W, and the heating temperature is set to 250 - 850 °C.

[0010] , The thermogravimetric analysis method according to any one of [6] - [9], wherein: The sample to be measured is dried before step 1); The drying temperature is 80 - 150 °C, and the drying time is 1 - 5 h. Effects of the Invention The thermogravimetric analysis device provided by the present invention realizes the effective combination of the microwave heating system and the thermogravimetric analysis system, can use a balance and a fixed-bed reaction tube to measure the weight change of the sample in real time under the action of a microwave field, and can measure the adsorption capacity and desorption capacity of the sample for CO 2 more accurately, and can more comprehensively and intuitively reflect the adsorption and desorption status of CO 2 . Using the thermogravimetric analysis method of the thermogravimetric analysis device for microwave-assisted CO 2 capture provided by the present invention, the weight measurement data is more accurate, the experimental repeatability is strong, and the adsorption-desorption cycle stability is good. In the thermogravimetric analysis device of the present invention, due to the design of the fixed-bed reaction tube, gas can flow directly and sufficiently through the sample, and mass transfer and heat transfer are more sufficient, making the adsorption and desorption efficiency higher. The design that the balance is entirely located outside the fixed-bed reaction tube effectively avoids the phenomenon of gas leakage. The microwave heating mode is single-mode microwave heating, and the microwave cavity is annular. The fixed-bed reaction tube vertically passes through the microwave cavity, which is more energy-stable and concentrated than the design of the traditional furnace cavity. It can make the microwave act on the sample intensively, is more energy-efficient, and can also effectively avoid microwave leakage. The design of the circulator can conduct the microwave evenly and intensively to the microwave cavity, and at the same time can prevent microwave reflection and avoid damaging the magnetron. Brief Description of the Drawings Figure 1 is the front structural schematic diagram of the thermogravimetric analysis device for microwave-assisted carbon dioxide capture of the present invention. Figure 2 is the side structural schematic diagram of the thermogravimetric analysis device for microwave-assisted carbon dioxide capture of the present invention. Figure 3 It is a top - down schematic view of the partial structure of the thermogravimetric analysis device for microwave - assisted carbon dioxide capture in the present invention. Figure 4 It is a time - adsorption value curve graph measured in the embodiment of the present invention. Explanation of reference numerals: 1: Controller, 2: Waveguide, 3: Magnetron, 4: Power supply, 5: Water load, 6: Circulator, 7: Circulating water tank, 8: Microwave cavity, 9: Balance, 10: Hanging wire, 11: Flange, 12: Inlet of quartz tube, 13: Quartz tube, 14: Sieve plate, 15: Outlet of quartz tube, 16: Short - wave infrared thermometer, 17: Computer. Detailed implementation manners The following will detail various exemplary embodiments, features, and aspects of the present invention. The special word "exemplary" here means "serving as an example, embodiment, or illustration". Any embodiment described as "exemplary" here does not necessarily have to be construed as superior to or better than other embodiments. In addition, to better illustrate the present invention, numerous specific details are given in the following detailed implementation manners. Those skilled in the art should understand that the present invention can still be implemented without some of these specific details. In other instances, methods, means, equipment, and steps well - known to those skilled in the art are not described in detail so as to highlight the gist of the present invention. Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production. In this specification, the meaning expressed by using "can" includes both the meaning of performing a certain process and the meaning of not performing a certain process. In this specification, the so - called "some specific / preferred implementation manners", "other specific / preferred implementation manners", "implementation manners", etc. refer to the specific elements (such as features, structures, properties, and / or characteristics) related to the implementation manner described, which are included in at least one of the implementation manners described here, and may exist in other implementation manners or may not exist in other implementation manners. Additionally, it should be understood that the elements can be combined in various implementation manners in any suitable way. In this specification, the numerical range expressed by using "numerical value A~numerical value B" refers to the range including the endpoint numerical values A and B. In this specification, when using "normal temperature" and "room temperature", the temperature can be 15°C~30°C, further 15°C~25°C, for example, 20°C. Microwave-assisted CO 2 Thermogravimetric analysis device for capture The present invention provides a microwave - assisted CO 2The captured thermogravimetric analysis device includes: a gas delivery and switching unit, a microwave-assisted reaction unit, a temperature measurement unit, a weight recording unit, and a gas analysis unit; The gas delivery and switching unit has a gas delivery structure and a gas mixing structure; The microwave-assisted reaction unit has a microwave generation structure, a waveguide, a circulator, and a microwave cavity; the microwave generation structure generates microwaves, which are conducted to the circulator through the waveguide and then conducted to the microwave cavity after being processed by the circulator; The weight recording unit has a fixed-bed reaction tube, a weight measurement structure, and a weight recording structure; the fixed-bed reaction tube is used to place the sample to be tested, the fixed-bed reaction tube passes through the microwave cavity, an air inlet is provided on the side of the fixed-bed reaction tube, one end of the fixed-bed reaction tube is connected to the weight measurement structure, and an air outlet is provided at one end; The gas analysis unit is connected to the air outlet of the fixed-bed reaction tube. In some embodiments, a sieve plate is provided in the fixed-bed reaction tube, and the sample to be tested is placed on the sieve plate. The design of this fixed-bed reaction tube can enable the gas to flow directly and sufficiently through the sample to be tested, and the gas and the sample to be tested can come into full contact and interact, significantly improving the heat and mass transfer effect between gas and solid. In the microwave-assisted reaction unit of the present invention, the microwave cavity is preferably annular, and the fixed-bed reaction tube vertically passes through the microwave cavity, which can effectively prevent microwave leakage and also enable the microwaves to act intensively on the sample to be tested in the fixed-bed reaction tube. A circulator is a non-reciprocal device mainly used to control the transmission direction of microwave signals. In the present invention, the circulator is located between the waveguide and the microwave cavity, which can conduct the microwaves evenly and intensively from the waveguide to the microwave cavity, and at the same time prevent the microwaves from rebounding to the waveguide and the magnetron, avoiding damage to the waveguide and the magnetron. In some embodiments, the microwave-assisted reaction unit further has a water load and a circulation water tank; the circulation water tank is connected with a circulation water pipe, and the circulation water pipe is placed inside the waveguide and is connected to the microwave generation structure, the circulator, the microwave cavity, and the water load. The circulation water tank and the circulation water pipe can absorb the reflected microwaves, further prevent microwave leakage, and at the same time can protect the magnetron. A water load is a device used to absorb microwave energy, mainly used to convert microwave energy into heat energy and take away the heat through a water cooling system. In the present invention, the water load is located on one side of the circulator, and the water load can absorb microwave energy and convert it into heat energy, prevent microwave rebound, and take away the heat through the circulation water pipe. In some embodiments, the microwave generation structure has a magnetron, a controller, and a power supply, the controller controls the power supply, and the power supply controls the magnetron. In the present invention, the magnetron is a device for generating microwaves. In the present invention, the magnetron generates only one specific electromagnetic field mode, that is, the magnetron of the present invention outputs single-mode microwaves. Single-mode transmission has the advantages of less microwave loss, high signal transmission effect, stable transmission, and concentrated and fixed microwaves. In some embodiments, the weight measurement structure has a balance, a hanging wire, and a flange. In some embodiments, the fixed-bed reaction tube is a quartz tube. In the present invention, the aperture of the sieve plate is not particularly limited as long as it can allow the gas to flow smoothly and does not leak the sample to be measured. In some specific embodiments, the aperture of the sieve plate is 0.05 - 2 mm, such as 1 mm, 1.5 mm, etc. In some embodiments, one end of the fixed-bed reaction tube is connected to the flange in the weight measurement structure. There is a hollow ring on the upper part of the flange, such as a cap with a hollow ring. The cap can play a role in sealing. The hanging wire passes through the hollow ring and is connected to the balance. In the present invention, the role of the flange is to connect the fixed-bed reaction tube and the hanging wire to facilitate the balance to weigh the fixed-bed reaction tube. In the present invention, the sieve plate of the fixed-bed reaction tube and the microwave cavity are in the same horizontal position to facilitate the microwave to act on the sample to be measured on the sieve plate through the fixed-bed reaction tube. In some embodiments, the weight recording structure has a computer. In some embodiments, the balance measures the weight of the fixed-bed reaction tube in real time and transmits the data to the computer. In some embodiments, the gas mixing structure has a gas distribution box. The gas outlet of the gas distribution box is communicated with the gas inlet of the fixed-bed reaction tube, and a flow meter is built in. In some embodiments, the gas analysis unit has a gas inlet, and the gas inlet is connected to the gas outlet of the fixed-bed reaction tube to complete the analysis of the components of the tail gas. In some embodiments, the temperature measurement unit has an infrared thermometer. The infrared thermometer measures the temperature of the sample to be measured, that is, the infrared thermometer can measure the surface temperature of the sample to be measured through the fixed-bed reaction tube and feedback the temperature to the controller of the microwave-assisted reaction unit to complete the measurement, recording, and feedback of the temperature. In the present invention, the size of the fixed-bed reaction tube is not particularly limited and can be adjusted according to actual needs. In some embodiments, the length of the fixed-bed reaction tube is 400 - 600 mm, such as 450 mm, 480 mm, 500 mm, 550 mm, etc.; the outer diameter is 8 - 20 mm, such as 10 mm, 12 mm, 15 mm, etc.; the inner diameter is 6 - 18 mm, such as 8 mm, 10 mm, 15 mm, etc. In some specific embodiments, the length of the fixed-bed reaction tube is 480 mm, the outer diameter is 10 mm, and the inner diameter is 8 mm. In some embodiments, the wall thickness of the fixed-bed reaction tube is 1 - 5 mm, such as 2 mm, 3 mm, 4 mm, etc. In some specific embodiments, the wall thickness of the fixed-bed reaction tube is 2 mm. In some embodiments, the inlet of the fixed-bed reaction tube is located between the upper end of the fixed-bed reaction tube and the sieve plate, and the outlet is located at the lower end of the fixed-bed reaction tube. In some specific embodiments, the inlet of the fixed-bed reaction tube is 20 - 60 mm away from the upper end, such as 30 mm, 40 mm, 50 mm, etc.; 100 - 400 mm away from the sieve plate, such as 150 mm, 200 mm, 300 mm, etc.; 300 - 800 mm away from the lower end of the fixed-bed reaction tube, such as 400 mm, 500 mm, 600 mm, etc. In some embodiments, the balance is an analytical balance. In some specific embodiments, the maximum measuring range of the analytical balance is 220 g, and the accuracy is 0.1 mg. In some embodiments, the maximum microwave output power of the microwave-assisted reaction unit is 1000 W. In some specific embodiments, the microwave output power of the microwave-assisted reaction unit is 0 - 1000 W, such as 200 W, 500 W, 800 W, etc. In some embodiments, the time resolution of the balance for real-time weight measurement is 0.01 - 1 s, such as 0.02 s, 0.05 s, 0.1 s, 0.2 s, 0.5 s, etc., and can be adjusted according to actual needs. In some embodiments, the time resolution of the gas analysis unit for analyzing the components of the tail gas is 0.1 - 5 s, such as 0.5 s, 1 s, 2 s, 3 s, etc., and can be adjusted according to actual needs. In some embodiments, the infrared thermometer is a short-wave infrared thermometer. In some embodiments, the temperature measurement range of the infrared thermometer is 0 - 2000 °C, preferably 200 - 2000 °C. In some embodiments, the CO of the gas analyzer 2 measurement range is 0 - 100%, the resolution is 0.01%, and the error does not exceed 2%. Microwave-assisted CO 2 Thermogravimetric analysis method for capture The present invention provides a thermogravimetric analysis method for microwave-assisted CO 2 capture, which has the advantage of using thermogravimetric analysis to study CO 2 capture. The balance and the suspended fixed-bed reaction tube can perform real-time measurement of weight changes, and the measurement results are more accurate and can more comprehensively reflect the adsorption and desorption conditions of CO 2 . The adsorption of CO 2 is carried out under normal temperature or microwave heating conditions, and the desorption of CO 2 is carried out under microwave heating conditions. First, a gas containing CO 2 is introduced for CO 2 adsorption, and then CO 2 desorption is carried out, and the adsorption and desorption processes of CO 2 are analyzed through weight changes. Specifically, the present invention provides a thermogravimetric analysis method for microwave-assisted CO 2 capture, which is carried out in the above-mentioned thermogravimetric analysis device for microwave-assisted CO 2 capture. The method includes the following steps: Step 1), placing the sample to be tested into the fixed-bed reaction tube; Step 2), causing the microwave generating structure to generate microwaves, and the microwaves are conducted to the circulator through the waveguide, and then conducted to the microwave cavity after being processed by the circulator, and the microwaves pass through the fixed-bed reaction tube and act on the sample to be tested; Step 3), introducing a gas containing CO 2 from the inlet of the fixed-bed reaction tube, and the gas containing CO 2 flows through the sample to be tested, and the sample to be tested completes the adsorption of CO 2 ; recording the real-time weighing value of the weight measurement structure and the real-time temperature of the sample to be tested; Step 4), introducing a gas from the inlet of the fixed-bed reaction tube, and the sample to be tested completes the desorption of CO 2 , and the desorbed gas is discharged through the outlet of the fixed-bed reaction tube; recording the real-time weighing value of the weight measurement structure and the real-time temperature of the sample to be tested. In some specific embodiments, the sample to be tested is an adsorption-wave absorbing bifunctional material, and the adsorption-wave absorbing bifunctional material includes an adsorption component and a microwave absorption component. In the present invention, the "adsorption component" refers to a substance that can absorb CO 2 under normal temperature or heating conditions. In some embodiments, the adsorption component of the present invention can be molecular sieve, calcium oxide, lithium zirconate, lithium silicate, etc. In some preferred embodiments, the adsorption component of the present invention can be 5A molecular sieve. In some specific embodiments, the 5A molecular sieve used in the present invention may be in the form of particles, and its average particle size may be 0.02 - 5 mm, such as 0.05 mm, 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 4 mm, etc. In some other specific embodiments, the 5A molecular sieve used in the present invention may also be in the form of powder. In the present invention, the "microwave absorption component" refers to a substance that can absorb electromagnetic waves and convert them into heat energy. In some embodiments, the microwave absorption component of the present invention may be silicon carbide (SiC), graphene, graphite, carbon fiber, or carbon nanotube, etc. In some preferred embodiments, the microwave absorption component of the present invention may be silicon carbide (SiC). In some specific embodiments, the SiC used in the present invention may be in the form of particles, and its average particle size may be 0.02 - 2 mm, such as 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.5 mm, 0.8, 1 mm, 1.5 mm, etc. In some embodiments, the mass ratio of the adsorption component to the microwave absorption component is 1:0.5 - 1:2, such as 1:0.8, 1:1, 1:1.2, 1:1.5, etc. In some embodiments, the adsorption-wave absorption bifunctional material is prepared by mixing the adsorption component and the microwave absorption component, and the mixing method may be physical mixing. For example, the adsorption component and the microwave absorption component are mixed evenly to obtain the adsorption-wave absorption bifunctional material. In some embodiments, in step 3), the microwave power and the heating temperature are set. The microwave power is not particularly limited and can be appropriately adjusted according to the selection of the adsorption-wave absorption bifunctional material. In some specific embodiments, in step 3), the microwave power can be set to 0 - 600 W, such as 100 W, 200 W, 400 W, 500 W, etc. The heating temperature is not particularly limited and can be appropriately adjusted according to the selection of the adsorption-wave absorption bifunctional material. In some specific embodiments, in step 3), the heating temperature can be set to 15 - 650 °C, such as 25 °C, 50 °C, 100 °C, 200 °C, 400 °C, 500 °C, etc. In some embodiments, in step 3), the adsorption is carried out at room temperature, that is, the microwave power and the heating temperature are not set in step 3). In some embodiments, in step 3), the gas containing CO 2 may be pure CO 2 , or a mixed gas of CO 2 and an inert gas, such as a mixed gas of CO 2 and N 2 . In some specific embodiments, CO2 In a mixed gas with an inert gas, CO 2 and the inert gas can have a volume ratio of 1:0.5 - 1:1.5, such as 1:1. In practical applications, the gas containing CO 2 introduced is the gas that needs to be subjected to CO 2 capture, such as flue gas and other gases. In some embodiments, the inert gas can be nitrogen, argon or helium. In some embodiments, in step 3), the gas containing CO 2 introduced has a flow rate of 50 - 200 mL / min, such as 80 mL / min, 100 mL / min, 150 mL / min, etc. In some embodiments, in step 4), the microwave power and heating temperature are set. The microwave power is not particularly limited and can be appropriately adjusted according to the selection of the adsorption - wave - absorbing bifunctional material. In some specific embodiments, in step 4), the microwave power can be set to 300 - 1000 W, such as 400 W, 500 W, 600 W, 700 W, 800 W, etc. The heating temperature is not particularly limited and can be appropriately adjusted according to the selection of the adsorption - wave - absorbing bifunctional material. In some specific embodiments, in step 4), the heating temperature can be set to 250 - 850 °C, such as 300 °C, 400 °C, 500 °C, 600 °C, 700 °C, 800 °C, etc. In some embodiments, in step 4), the gas introduced from the inlet of the fixed - bed reaction tube is not particularly limited and can be a gas containing CO 2 and / or an inert gas, such as a mixed gas of CO 2 and an inert gas, pure inert gas or pure CO 2 . In some specific embodiments, in the mixed gas of CO2 and an inert gas, the volume ratio of CO2 and the inert gas can be 1:0.5 - 1:1.5, such as 1:1. In some embodiments, in step 4), the gas introduced from the inlet of the fixed - bed reaction tube has a flow rate of 50 - 200 mL / min, such as 80 mL / min, 100 mL / min, 150 mL / min, etc. In some embodiments, the test sample needs to be dried before step 1). The drying step can remove the moisture in the test sample to prevent moisture from affecting CO 2It affects the measurement accuracy of adsorption and desorption. In some specific embodiments, the drying temperature can be 80-150°C, such as 90°C, 100°C, 120°C, 140°C, etc. In some specific embodiments, the drying time can be 1-5 h, such as 1.5 h, 2 h, 3 h, 4 h, etc. In some embodiments, in step 3), the gas after adsorption is discharged through the outlet of the fixed-bed reaction tube and enters the gas analysis unit for analysis of the tail gas components. In some embodiments, in step 4), the gas after desorption is discharged through the outlet of the fixed-bed reaction tube and enters the gas analysis unit for analysis of the tail gas components. Examples The embodiments of the present invention will be described in detail below in conjunction with examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. Those not specified in the examples are carried out under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments not indicated by the manufacturer can be obtained as conventional products through commercial purchase. The microwave-assisted CO used in the examples 2 The front structural schematic diagram of the thermogravimetric analysis device for microwave-assisted CO capture is as Figure 1 shown, and the side structural schematic diagram is as Figure 2 shown. The top view (schematic diagram) of the local structure (the structure of the circulator, water load, and microwave cavity) is as Figure 3 shown. The microwave-assisted CO used in the examples 2 The thermogravimetric analysis device for capture specifically includes a gas delivery and switching unit, a microwave-assisted reaction unit, a temperature measurement unit, a weight recording unit, and a gas analysis unit. The microwave-assisted reaction unit includes a power supply (4), a controller (1), a magnetron (3), a waveguide (2), a circulator (6), a water load (5), a microwave cavity (8), and a circulation water tank (7), with a maximum microwave output power of 1000 W. The controller controls the power supply to be turned on, enabling the magnetron to generate microwaves. The microwaves are conducted to the circulator through the waveguide, and after being processed by the circulator, they are conducted to the microwave cavity, which is annular. The circulation water tank is connected with a circulation water pipe, and the circulation water pipe is placed inside the waveguide and connected to the magnetron, circulator, water load, and microwave cavity to absorb the reflected microwaves and protect the magnetron. The weight recording unit includes a quartz tube (13), a hanging wire (10), a flange (11), a balance (9), and a computer (17). A sieve plate (14) is built into the quartz tube, and the sample to be measured is filled on the sieve plate. The aperture of the sieve plate is 1 mm. The quartz tube is 480 mm long, with an outer diameter of 10 mm, an inner diameter of 8 mm, and a wall thickness of 2 mm. An air inlet (12) is provided on the side of the quartz tube, which is located between the upper end of the quartz tube and the sieve plate. The air inlet is 40 mm away from the upper end of the quartz tube, 200 mm away from the sieve plate, and 440 mm away from the lower end of the quartz tube; an air outlet (15) is located at the lower end of the quartz tube. A flange is provided at the upper end of the quartz tube, and a hollow ring is provided on the upper part of the flange. The hanging wire passes through the hollow ring and is connected to the balance. The balance measures the weight of the quartz tube in real time and transmits the data to the computer. The balance is an analytical balance with a maximum range of 220 g and an accuracy of 0.1 mg. The computer records the weighing value of the balance in real time. The quartz tube vertically passes through the microwave cavity, and the sieve plate of the quartz tube and the microwave cavity are at the same horizontal position. The temperature measuring unit includes a short-wave infrared thermometer (16) with a temperature measuring range of 200 - 2000 °C. The short-wave infrared thermometer measures the surface temperature of the sample to be measured through the quartz tube and feeds back the temperature to the controller of the microwave-assisted reaction unit to complete the measurement, recording, and feedback of the temperature. The gas delivery and switching unit includes a gas distribution box connected to the CO 2 and N 2 gas sources, which is located on one side of the microwave thermogravimetric analysis device. The air outlet of the gas distribution box is communicated with the air inlet of the quartz tube. The gas distribution box is communicated with the air inlet of the quartz tube through a hose and is internally provided with a flow meter with a range of 0 - 100 ml / min. The gas analysis unit includes a gas analyzer. The air inlet of the gas analyzer is connected to the air outlet of the quartz tube to analyze the components of the tail gas; the CO 2 range is 0 - 100%, the resolution is 0.01%, and the error does not exceed 2%. In the embodiment, the sample to be measured used is an adsorption-wave absorption dual-functional material, which is a mixed material of an adsorption component and a microwave absorption component. The adsorption component is 5A molecular sieve, and the microwave absorption component is SiC. The mass ratio of the adsorption component to the microwave absorption component is 1:1. The specific synthesis method is as follows: Mix 5A molecular sieve and SiC evenly to obtain the adsorption-wave absorption dual-functional material. The 5A molecular sieve used in the embodiment is produced by 3A Chem Company, with the product number A17090 and the property of powder; silicon carbide (SiC) is produced by Alfa Aesar Company, with the product number A14470 and an average particle size of 300 - 425 μm. The specific steps of the thermogravimetric analysis method for microwave-assisted CO 2 capture are as follows: 1) After heating and drying the adsorption-wave-absorbing dual-functional material in an oven at 100 °C for 2 h, take 1.0 g and place it on the sieve plate of the quartz tube, and record the weighing value of the balance before CO adsorption. 2 2) CO adsorption: 2 The CO adsorption is carried out at room temperature (25 °C). A mixed gas of 50 ml / min of CO and 50 ml / min of N is introduced from the inlet of the quartz tube. The mixed gas flows vertically through the adsorption-wave-absorbing dual-functional material from top to bottom to achieve the capture of CO in the simulated flue gas. The low-carbon flue gas after adsorption is discharged through the outlet of the quartz tube and enters the gas analyzer; record the real-time weighing value of the balance, and the time resolution of the balance is 0.05 s; subtract the weighing value of the balance before CO adsorption in step 1) from the real-time weighing value of the balance to obtain the adsorption value; at the same time, measure the temperature of the adsorption-wave-absorbing dual-functional material in real time; the adsorption time is set to 15 min. 2 2 2 2 2 3) CO desorption: 2 In the microwave-assisted reaction unit, the controller controls to turn on the power supply to make the magnetron generate microwaves. Set the microwave power to 500 W and the heating temperature to 250 °C; the microwaves are conducted to the circulator through the waveguide, and then conducted to the microwave cavity after being processed by the circulator. The quartz tube vertically passes through the microwave cavity, and the microwaves act on the adsorption-wave-absorbing dual-functional material through the quartz; at the same time, turn on the circulating water tank, and circulating water flows in the circulating water pipe; continue to introduce a mixed gas of 50 ml / min of CO and 50 ml / min of N from the inlet of the quartz tube. The gas after desorption is discharged through the outlet of the quartz tube and enters the gas analyzer; record the real-time weighing value of the balance and calculate the adsorption value, and measure the temperature of the adsorption-wave-absorbing dual-functional material in real time; the desorption time is set to 7.5 min. 2 2 4) Repeat steps 2) and 3) for 3 cycles. 5) Turn off the balance weight recording program, the short-wave infrared thermometer, the gas analyzer, and turn off the power supply in the microwave-assisted reaction unit. After detection, there is no air leakage in the thermogravimetric analysis device for microwave-assisted CO capture of the present invention during the processes of CO adsorption and desorption. 2 2 Taking time (s) as the abscissa and adsorption value (g) as the ordinate, statistically analyze the 3 cycles and draw a time-adsorption value curve, as shown in Figure 4 , and the weight data of the thermogravimetric system can intuitively reflect the capture situation of CO. 2 Figure 4It can be seen that the thermogravimetric analysis device and method for microwave-assisted CO 2 capture have fast adsorption and desorption processes, high efficiency, and still have good stability and strong repeatability after multiple cycle tests. It should be noted that although the technical solutions of the present invention are introduced by specific examples, those skilled in the art can understand that the present invention should not be limited thereto. The embodiments of the present invention have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to technologies in the market, or to enable other ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A thermogravimetric analysis device for microwave-assisted carbon dioxide capture, comprising: Gas delivery and switching unit, microwave-assisted reaction unit, temperature measurement unit, weight recording unit and gas analysis unit; The gas delivery and switching unit has a gas delivery structure and a gas mixing structure; The microwave-assisted reaction unit comprises a microwave generating structure, a waveguide, a circulator and a microwave cavity; The microwave generating structure generates microwaves, which are transmitted to the circulator through the waveguide, and then transmitted to the microwave cavity after being processed by the circulator; The weight recording unit comprises a fixed bed reaction tube, a weight measuring structure and a weight recording structure; the fixed bed reaction tube is used to place the sample to be tested, the fixed bed reaction tube passes through the microwave cavity, an air inlet is arranged on the side of the fixed bed reaction tube, one end of the fixed bed reaction tube is connected to the weight measuring structure, and the other end is provided with an air outlet; The gas analysis unit is communicated with the gas outlet of the fixed bed reaction tube.

2. The thermogravimetric analysis device according to claim 1, characterized in that: The microwave-assisted reaction unit also has a water load and a circulating water tank; the circulating water tank is connected to a circulating water pipe, the circulating water pipe is built into the waveguide, and is connected to the microwave generating structure, the circulator, the microwave cavity and the water load.

3. The thermogravimetric analysis device according to claim 1 or 2, characterized in that: The microwave generating structure comprises a magnetron, a controller and a power supply, wherein the controller controls the power supply and the power supply controls the magnetron.

4. The thermogravimetric analysis device according to any one of claims 1 to 3, characterized in that: The weight measuring structure comprises a balance, a hanging wire and a flange; The fixed bed reaction tube is a quartz tube; A sieve plate is provided in the fixed bed reaction tube, and the sample to be tested is placed on the sieve plate; One end of the fixed bed reaction tube is connected to the flange in the weight measuring structure, a hollow ring is provided on the upper part of the flange, and the hanging wire passes through the hollow ring and is connected to the balance.

5. The thermogravimetric analysis device according to any one of claims 1 to 4, characterized in that: The gas mixing structure has a gas distribution box, the gas outlet of the gas distribution box is connected to the gas inlet of the fixed bed reaction tube, and a flow meter is built in; The gas analysis unit has an air inlet, and the air inlet of the gas analyzer is connected to the air outlet of the fixed bed reaction tube; The temperature measuring unit has an infrared thermometer.

6. A method for thermogravimetric analysis of microwave-assisted carbon dioxide capture, which is carried out in the thermogravimetric analysis apparatus according to any one of claims 1 to 5, comprising the following steps: Step 1), placing the sample to be tested into the fixed bed reaction tube; Step 2), the microwave generating structure generates microwaves, the microwaves are transmitted to the circulator through the waveguide, and then transmitted to the microwave cavity after being processed by the circulator, and the microwaves act on the sample to be tested through the fixed bed reaction tube; Step 3), introducing a gas containing carbon dioxide from the air inlet of the fixed bed reaction tube, the gas containing carbon dioxide flows through the sample to be tested, and the sample to be tested completes the adsorption of carbon dioxide; Recording the real-time weighing value of the weight measuring structure and the real-time temperature of the sample to be measured; Step 4), introducing gas from the air inlet of the fixed bed reaction tube, the sample to be tested completes the desorption of carbon dioxide, and the desorbed gas is discharged through the air outlet of the fixed bed reaction tube; The real-time weighing value of the weight measuring structure and the real-time temperature of the sample to be measured are recorded.

7. The thermogravimetric analysis method according to claim 6, characterized in that: The sample to be tested is an adsorption-wave absorption dual-function material, and the adsorption-wave absorption dual-function material comprises an adsorption component and a microwave absorption component; The adsorption component is molecular sieve, calcium oxide, lithium zirconate or lithium silicate; The microwave absorbing component is silicon carbide, graphene, graphite, carbon fiber or carbon nanotube; The mass ratio of the adsorption component to the microwave absorption component is 1:0.5-1:

2.

8. The thermogravimetric analysis method according to claim 6 or 7, characterized in that: In step 3), microwave power and heating temperature are set; In step 3), the microwave power is set to 0-600W, and the heating temperature is set to 15-650°C.

9. The thermogravimetric analysis method according to any one of claims 6 to 8, characterized in that: In step 4), microwave power and heating temperature are set; In step 4), the microwave power is set to 300-1000W, and the heating temperature is set to 250-850°C.

10. The thermogravimetric analysis method according to any one of claims 6 to 9, characterized in that: Before step 1), the sample to be tested is dried; The drying temperature is 80-150° C., and the drying time is 1-5 hours.

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