Thermogravimetric analysis device for microwave-assisted carbon dioxide capture

Abstract

The utility model provides a thermogravimetric analysis device 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 and heat transfer is 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.

Description

Technical Field

[0001] This utility model belongs to the field of thermogravimetric analysis technology and relates to a microwave-assisted carbon dioxide capture thermogravimetric analysis device. Background Technology

[0002] Thermogravimetric analysis (TGA) is an important method for studying material properties and reaction mechanisms. Traditional TGA techniques provide heat to the reaction materials through electrical heating, which is an external heating method. Microwave heating has advantages such as rapid heating, uniform heating, easy control, energy saving, and safety without pollution. It also generates a temperature gradient opposite to that of traditional electrical heating, which may alter the reaction pathway.

[0003] Existing thermogravimetric analysis (TGA) devices mostly use electric heating, which cannot achieve real-time measurement of sample weight under microwave conditions. Current microwave TGA technology is not perfect. For example, the microwave TGA device disclosed in CN108680458A still has the following problems: 1) Uneven microwave distribution, poor controllability of the heating area in repeated tests, large random errors, and a risk of microwave leakage; 2) The balance support extends into the reaction chamber, resulting in slight gas leakage, and the anti-leakage device is complex and redundant; 3) The gas cannot fully contact the sample, leading to poor heat and mass transfer.

[0004] Carbon capture technology is a technique that reduces greenhouse gas emissions by separating CO2 from industrial emission sources or the atmosphere, playing a crucial role in addressing global climate change and achieving carbon neutrality. Thermogravimetric analysis (TGA) can record the CO2 adsorption and regeneration process in real time, accurately reflecting the adsorption characteristics of materials. Microwave heating can reduce CO2 regeneration energy consumption and increase CO2 desorption rate, which is of great significance to the development of carbon capture technology. For example, CN109200749A discloses a temperature-switching adsorption carbon capture system with microwave heating-assisted desorption process. This system uses microwave heating for CO2 desorption, improving CO2 desorption efficiency; however, it does not monitor adsorption / desorption data in real time, and this method cannot accurately and comprehensively reflect the CO2 adsorption / desorption status. Utility Model Content

[0005] Problems to be solved by utility models

[0006] To address the problems existing in the above-mentioned technologies, this utility model aims to provide a microwave-assisted thermogravimetric analysis (TGA) device for carbon dioxide capture. This utility model's TGA device combines a microwave heating system and a thermogravimetric analysis system, enabling real-time measurement of sample weight under a microwave field. The fixed-bed reaction tube design improves gas-solid heat and mass transfer, and the overall balance location outside the fixed-bed reaction tube effectively prevents gas leakage. The single-mode microwave output, the annular microwave cavity design, and the circulator design fix the microwave concentration point, further preventing microwave leakage. Using this utility model's TGA device, carbon dioxide adsorption-desorption experiments exhibit strong repeatability and good cycle stability.

[0007] Solution for solving the problem

[0008] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0009] This utility model provides a microwave-assisted carbon dioxide capture thermogravimetric analysis device, which 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;

[0010] The gas delivery and switching unit has a gas delivery structure and a gas mixing structure;

[0011] The microwave-assisted reaction unit has a microwave generating structure, a waveguide, a circulator, and a microwave cavity; the microwave generating structure generates microwaves, which are conducted through the waveguide to the circulator, processed by the circulator, and then conducted to the microwave cavity;

[0012] The weight recording unit has 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, the fixed-bed reaction tube has an air inlet on its side, one end of the fixed-bed reaction tube is connected to the weight measuring structure, and the other end has an air outlet.

[0013] The gas analysis unit is connected to the gas outlet of the fixed-bed reaction tube.

[0014] According to the thermogravimetric analysis apparatus described above, wherein:

[0015] 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, which is built into the waveguide and connected to the microwave generating structure, the circulator, the microwave cavity and the water load.

[0016] According to the thermogravimetric analysis apparatus described above, wherein:

[0017] The microwave generating structure has a magnetron, a controller, and a power supply. The controller controls the power supply, and the power supply controls the magnetron.

[0018] According to the thermogravimetric analysis apparatus described above, wherein:

[0019] The weight measuring structure includes a balance, a wire hanging device, and a flange.

[0020] The fixed-bed reaction tube is a quartz tube;

[0021] The fixed-bed reaction tube is equipped with a sieve plate, on which the sample to be tested is placed;

[0022] 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.

[0023] According to the thermogravimetric analysis apparatus described above, wherein:

[0024] The gas mixing structure has a gas distribution box, the gas outlet of which is connected to the gas inlet of the fixed bed reaction tube, and has a built-in flow meter;

[0025] The gas analysis unit has an air inlet, which is connected to the air outlet of the fixed bed reaction tube.

[0026] The temperature measuring unit includes an infrared thermometer.

[0027] Effects of the utility model

[0028] The thermogravimetric analysis (TGA) device provided by this invention effectively combines a microwave heating system and a TGA system. It can measure the weight change of the sample in real time using a balance and a fixed-bed reaction tube under microwave field conditions. It can also measure the sample's CO2 adsorption and desorption capacity in real time. The weight measurement data from the TGA system is more accurate and can more comprehensively and intuitively reflect the CO2 adsorption and desorption status. The CO2 adsorption-desorption experiments using the microwave-assisted CO2 capture TGA device provided by this invention exhibit strong repeatability, more accurate weight measurement data, and good cycle stability during adsorption-desorption.

[0029] The fixed-bed reaction tube design in this thermogravimetric analysis device allows gas to flow directly and fully through the sample, resulting in more efficient mass and heat transfer and higher adsorption and desorption efficiency. The balance is positioned entirely outside the fixed-bed reaction tube, effectively preventing gas leakage. The microwave heating mode is single-mode microwave heating, with a ring-shaped microwave cavity through which the fixed-bed reaction tube passes perpendicularly. This design provides more stable and concentrated energy compared to traditional furnace-type cavity designs, allowing microwaves to focus on the sample, resulting in greater energy savings and effectively preventing microwave leakage. The circulator design ensures uniform and concentrated microwave conduction to the microwave cavity while preventing microwave bounce and damage to the magnetron. Attached Figure Description

[0030] Figure 1 This is a front structural schematic diagram of the microwave-assisted carbon dioxide capture thermogravimetric analysis device of this utility model.

[0031] Figure 2 This is a side view of the thermogravimetric analysis device for microwave-assisted carbon dioxide capture according to this utility model.

[0032] Figure 3 This is a top view schematic diagram of a partial structure of the microwave-assisted carbon dioxide capture thermogravimetric analysis device of this utility model.

[0033] Figure 4 This is a time-adsorption value curve measured in an embodiment of this utility model.

[0034] Explanation of reference numerals in the attached figures:

[0035] 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: Air inlet of quartz tube, 13: Quartz tube, 14: Sieve plate, 15: Air outlet of quartz tube, 16: Shortwave infrared thermometer, 17: Computer. Detailed Implementation

[0036] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments.

[0037] Furthermore, to better illustrate this utility model, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this utility model can be implemented without certain specific details. In other instances, methods, means, equipment, and steps well-known to those skilled in the art have not been described in detail, in order to highlight the main points of this utility model.

[0038] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this utility model should be understood to include systematic errors that are unavoidable in industrial production.

[0039] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0040] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.

[0041] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0042] In this instruction manual, when "room temperature" or "room temperature" is used, the temperature can be 15℃~30℃, or more specifically 15℃~25℃, such as 20℃.

[0043] Microwave-assisted CO2 capture thermogravimetric analysis device

[0044] This utility model provides a microwave-assisted CO2 capture thermogravimetric analysis device, which 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;

[0045] The gas delivery and switching unit has a gas delivery structure and a gas mixing structure;

[0046] The microwave-assisted reaction unit has a microwave generating structure, a waveguide, a circulator, and a microwave cavity; the microwave generating structure generates microwaves, which are conducted through the waveguide to the circulator, processed by the circulator, and then conducted to the microwave cavity;

[0047] The weight recording unit has 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, the fixed-bed reaction tube has an air inlet on its side, one end of the fixed-bed reaction tube is connected to the weight measuring structure, and the other end has an air outlet.

[0048] The gas analysis unit is connected to the gas outlet of the fixed-bed reaction tube.

[0049] In some embodiments, the fixed-bed reaction tube is equipped with a sieve plate on which the sample to be tested is placed. This design of the fixed-bed reaction tube allows the gas to flow directly and fully through the sample to be tested, enabling the gas and the sample to come into full contact and interact, significantly improving the gas-solid heat and mass transfer effect.

[0050] In the microwave-assisted reaction unit of this invention, the microwave cavity is preferably annular, and the fixed-bed reaction tube passes vertically through the microwave cavity, which can effectively prevent microwave leakage and also concentrate the microwave on the sample to be tested in the fixed-bed reaction tube.

[0051] A circulator is a non-reciprocal device primarily used to control the transmission direction of microwave signals. In this invention, the circulator is located between the waveguide and the microwave cavity, enabling uniform and concentrated microwave transmission from the waveguide to the microwave cavity, while preventing microwaves from bouncing back to the waveguide and magnetron, thus avoiding damage to these components.

[0052] In some embodiments, the microwave-assisted reaction unit further includes a water load and a circulating water tank; the circulating water tank is connected to a circulating water pipe, which is built into the waveguide and connected to the microwave generating structure, the circulator, the microwave cavity, and the water load. The circulating water tank and circulating water pipe can absorb reflected microwaves, further preventing microwave leakage, and also protecting the magnetron.

[0053] A water load is a device used to absorb microwave energy, primarily converting it into heat energy and removing the heat through a water cooling system. In this invention, the water load is located on one side of the circulator. The water load absorbs microwave energy, converts it into heat energy, prevents microwave bounce, and removes the heat through a circulating water pipe.

[0054] In some embodiments, the microwave generating structure has a magnetron, a controller, and a power supply, wherein the controller controls the power supply, and the power supply controls the magnetron.

[0055] In this invention, the magnetron is a device for generating microwaves. In this invention, the magnetron generates only one specific electromagnetic field mode; that is, the magnetron of this invention is a single-mode microwave output. Single-mode transmission has the advantages of low microwave loss, high signal transmission efficiency, stable transmission, and concentrated and fixed microwave output.

[0056] In some embodiments, the weight measuring structure has a balance, a wire, and a flange.

[0057] In some implementations, the fixed-bed reaction tube is a quartz tube.

[0058] In this invention, the aperture of the sieve plate is not particularly limited, as long as it allows gas to flow smoothly without leakage of the sample to be tested. In some specific embodiments, the aperture of the sieve plate is 0.05-2 mm, such as 1 mm, 1.5 mm, etc.

[0059] In some embodiments, one end of the fixed-bed reaction tube is connected to a flange in the weight measuring structure, and the upper part of the flange is provided with a hollow ring, such as a cap with a hollow ring, which can serve as a seal, and the hanging wire passes through the hollow ring and is connected to the balance.

[0060] In this invention, the flange serves to connect the fixed-bed reaction tube and the hanging wire, so that the balance can weigh the fixed-bed reaction tube.

[0061] In this invention, the sieve plate of the fixed-bed reaction tube and the microwave cavity are at the same horizontal position, so as to facilitate the microwave to pass through the fixed-bed reaction tube and act on the sample to be tested on the sieve plate.

[0062] In some implementations, the weight recording structure includes a computer.

[0063] In some implementations, the balance measures the weight of the fixed-bed reaction tube in real time and transmits the data to a computer.

[0064] In some embodiments, the gas mixing structure has a gas distribution box, the outlet of which is connected to the inlet of the fixed bed reaction tube, and a built-in flow meter.

[0065] In some embodiments, the gas analysis unit has an air inlet connected to the air outlet of the fixed-bed reaction tube to perform analysis of the exhaust gas components.

[0066] In some implementations, the temperature measuring unit has an infrared thermometer that measures the temperature of the sample to be tested. That is, the infrared thermometer can test the surface temperature of the sample to be tested through the fixed bed reaction tube and feed the temperature back to the controller of the microwave-assisted reaction unit to complete the measurement, recording and feedback of the temperature.

[0067] In this 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.; and 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.

[0068] 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.

[0069] In some embodiments, the air inlet of the fixed-bed reactor tube is located between the upper end of the fixed-bed reactor tube and the sieve plate, and the air outlet is located at the lower end of the fixed-bed reactor tube. In some specific embodiments, the air inlet of the fixed-bed reactor tube is 20-60 mm from the upper end, for example, 30 mm, 40 mm, 50 mm, etc.; 100-400 mm from the sieve plate, for example, 150 mm, 200 mm, 300 mm, etc.; and 300-800 mm from the lower end of the fixed-bed reactor tube, for example, 400 mm, 500 mm, 600 mm, etc.

[0070] In some embodiments, the balance is an analytical balance. In some specific embodiments, the analytical balance has a maximum range of 220 g and an accuracy of 0.1 mg.

[0071] 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.

[0072] In some implementations, the time resolution for real-time weight measurement by the balance is 0.01-1 s, such as 0.02 s, 0.05 s, 0.1 s, 0.2 s, 0.5 s, etc., which can be adjusted according to actual needs.

[0073] In some implementations, the time resolution of the gas analysis unit for analyzing exhaust gas components is 0.1-5 s, such as 0.5 s, 1 s, 2 s, 3 s, etc., which can be adjusted according to actual needs.

[0074] In some implementations, the infrared thermometer is a shortwave infrared thermometer.

[0075] In some implementations, the infrared thermometer has a temperature measurement range of 0-2000℃, preferably 200-2000℃.

[0076] In some implementations, the gas analyzer has a CO2 range of 0-100%, a resolution of 0.01%, and an error of no more than 2%.

[0077] Thermogravimetric Analysis Method for Microwave-Assisted CO2 Capture

[0078] This invention provides a thermogravimetric analysis method for microwave-assisted CO2 capture. Its advantage lies in using thermogravimetric analysis to study CO2 capture. The balance and suspended fixed-bed reaction tube can measure weight changes in real time, resulting in more accurate measurement results that can more comprehensively reflect the adsorption and desorption of CO2.

[0079] CO2 adsorption was carried out at room temperature or under microwave heating conditions, and CO2 desorption was carried out under microwave heating conditions. First, a gas containing CO2 was introduced to adsorb CO2, and then CO2 desorption was carried out. The adsorption and desorption processes of CO2 were analyzed by weight changes.

[0080] Specifically, this utility model provides a thermogravimetric analysis method for microwave-assisted CO2 capture, which is carried out in the aforementioned microwave-assisted CO2 capture thermogravimetric analysis apparatus. The method includes the following steps:

[0081] Step 1) Place the sample to be tested into the fixed-bed reaction tube;

[0082] Step 2) The microwave generating structure generates microwaves, which are then conducted to the circulator through the waveguide, processed by the circulator, and then conducted to the microwave cavity. The microwaves then act on the sample to be tested through the fixed-bed reaction tube.

[0083] Step 3) Introduce CO2-containing gas through the inlet of the fixed-bed reaction tube. The CO2-containing gas flows through the sample to be tested, and the sample to be tested completes the adsorption of CO2. Record the real-time weighing value of the gravimetric measuring structure and the real-time temperature of the sample to be tested.

[0084] Step 4) Gas is introduced into the inlet of the fixed-bed reaction tube, and the sample to be tested completes the desorption of CO2, so that the desorbed gas is discharged through the outlet of the fixed-bed reaction tube; record the real-time weighing value of the gravimetric structure and the real-time temperature of the sample to be tested.

[0085] In some specific implementation schemes, the sample to be tested is an adsorption-absorbing dual-functional material, which includes an adsorption component and a microwave absorption component.

[0086] In this invention, "adsorption component" refers to a substance capable of absorbing CO2 at room temperature or under heating conditions. In some embodiments, the adsorption component may be a molecular sieve, calcium oxide, lithium zirconate, or lithium silicate, etc. In some preferred embodiments, the adsorption component may be a 5A molecular sieve.

[0087] In some specific embodiments, the 5A molecular sieve can be granules with an average particle size of 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 other specific embodiments, the 5A molecular sieve can also be powder.

[0088] In this invention, "microwave absorbing component" refers to a substance capable of absorbing electromagnetic waves and converting them into heat energy. In some embodiments, the microwave absorbing component may be silicon carbide (SiC), graphene, graphite, carbon fiber, or carbon nanotubes, etc. In some preferred embodiments, the microwave absorbing component may be silicon carbide (SiC).

[0089] In some specific implementations, the SiC can be particles with an average particle size of 0.02-2 mm, such as 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.5 mm, 0.8 mm, 1 mm, 1.5 mm, etc.

[0090] In some embodiments, the mass ratio of the adsorbent component to the microwave absorbing component is 1:0.5-1:2, such as 1:0.8, 1:1, 1:1.2, 1:1.5, etc.

[0091] In some embodiments, the adsorption-absorbing bifunctional material is prepared by mixing an adsorption component and a microwave absorbing component, and the mixing method can be physical mixing. For example, the adsorption component and the microwave absorbing component are mixed evenly to obtain the adsorption-absorbing bifunctional material.

[0092] In some implementations, the microwave power and heating temperature are set in step 3). The microwave power is not particularly limited and can be adjusted appropriately based on the selection of the adsorption-absorbing bifunctional material. In some specific implementations, the microwave power in step 3) can be set to 0-600 W, for example, 100 W, 200 W, 400 W, 500 W, etc. The heating temperature is not particularly limited and can be adjusted appropriately based on the selection of the adsorption-absorbing bifunctional material. In some specific implementations, the heating temperature in step 3) can be set to 15-650°C, for example, 25°C, 50°C, 100°C, 200°C, 400°C, 500°C, etc.

[0093] In some implementations, the adsorption in step 3) is carried out at room temperature, that is, microwave power and heating temperature are not set in step 3).

[0094] In some implementations, in step 3), the CO2-containing gas introduced can be pure CO2 or a mixture of CO2 and an inert gas, such as a mixture of CO2 and N2. In some specific implementations, the volume ratio of CO2 to the inert gas in the CO2 and inert gas mixture can be 1:0.5 to 1:1.5, for example, 1:1. In practical applications, the CO2-containing gas introduced is the gas that needs to be CO2 captured, such as flue gas.

[0095] In some implementations, the inert gas may be nitrogen, argon, or helium.

[0096] In some implementations, in step 3), the flow rate of the CO2-containing gas introduced is 50-200 mL / min, for example 80 mL / min, 100 mL / min, 150 mL / min, etc.

[0097] In some implementations, the microwave power and heating temperature are set in step 4). The microwave power is not particularly limited and can be adjusted appropriately based on the selection of the adsorption-absorbing bifunctional material. In some specific implementations, the microwave power in step 4) can be set to 300-1000 W, such as 400 W, 500 W, 600 W, 700 W, 1000 W, etc. The heating temperature is not particularly limited and can be adjusted appropriately based on the selection of the adsorption-absorbing bifunctional material. In some specific implementations, the heating temperature in step 4) can be set to 250-850°C, such as 300°C, 400°C, 500°C, 600°C, 700°C, 800°C, etc.

[0098] In some embodiments, in step 4), the gas introduced from the inlet of the fixed-bed reactor tube is not particularly limited and can be a gas containing CO2 and / or an inert gas, such as a mixture of CO2 and an inert gas, a pure inert gas, or pure CO2. In some specific embodiments, the volume ratio of CO2 to the inert gas in the mixture can be 1:0.5 to 1:1.5, for example, 1:1.

[0099] In some implementations, in step 4), the flow rate of the gas introduced from the inlet of the fixed-bed reaction tube is 50-200 mL / min, for example 80 mL / min, 100 mL / min, 150 mL / min, etc.

[0100] In some embodiments, the sample to be tested needs to be dried before step 1). The drying step removes moisture from the sample to prevent it from affecting the accuracy of CO2 adsorption and desorption measurements. 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 hours, such as 1.5 hours, 2 hours, 3 hours, 4 hours, etc.

[0101] In some implementations, in step 3), the adsorbed gas is discharged through the outlet of the fixed bed reaction tube and enters the gas analysis unit for analysis of the tail gas components.

[0102] In some implementations, in step 4), the desorbed gas is discharged through the outlet of the fixed bed reaction tube and enters the gas analysis unit for analysis of the tail gas components.

[0103] Example

[0104] The embodiments of this utility model will be described in detail below. However, those skilled in the art will understand that the following embodiments are only for illustrating this utility model and should not be considered as limiting the scope of this utility model. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0105] A front view of the thermogravimetric analysis device for microwave-assisted CO2 capture used in this embodiment is shown in the figure. Figure 1 As shown in the schematic diagram of the side structure, Figure 2 As shown, a top view (schematic diagram) of the partial structure (structure of the circulator, water load, and microwave cavity) is shown. Figure 3 As shown. The microwave-assisted CO2 capture thermogravimetric analysis device used in this embodiment 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.

[0106] 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 circulating water tank (7), with a maximum microwave output power of 1000 W. The controller controls the power supply to turn on, energizing the magnetron to generate microwaves. The microwaves are conducted through the waveguide to the circulator, processed by the circulator, and then conducted to the microwave cavity, which is annular. The circulating water tank is connected to a circulating water pipe, which is built into the waveguide and connected to the magnetron, circulator, water load, and microwave cavity to absorb reflected microwaves and protect the magnetron.

[0107] 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 tested is filled on the sieve plate. The sieve plate has a pore size of 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 located on the side of the quartz tube, between the upper end of the quartz tube and the sieve plate. The air inlet is 40 mm from the upper end of the quartz tube, 200 mm from the sieve plate, and 440 mm 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 located at the upper end of the quartz tube, and a hollow ring is located on the upper part of the flange. The hanging wire passes through the hollow ring and connects 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 capacity 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 passes vertically through the microwave cavity, and the sieve plate of the quartz tube and the microwave cavity are at the same horizontal position.

[0108] The temperature measurement unit includes a short-wave infrared thermometer (16) with a temperature measurement range of 200-2000°C. The short-wave infrared thermometer measures the surface temperature of the sample under test through a quartz tube and feeds the temperature back to the controller of the microwave-assisted reaction unit to complete the measurement, recording and feedback of the temperature.

[0109] The gas delivery and switching unit includes a gas distribution box connected to CO2 and N2 gas sources, located on one side of the microwave thermogravimetric analysis device. The outlet of the gas distribution box is connected to the inlet of the quartz tube, and the gas distribution box is connected to the inlet of the quartz tube via a flexible hose. It has a built-in flow meter with a range of 0-100 ml / min.

[0110] The gas analysis unit includes a gas analyzer, whose inlet is connected to the outlet of a quartz tube to analyze the components of the exhaust gas; the CO2 range is 0-100%, the resolution is 0.01%, and the error does not exceed 2%.

[0111] The sample used in this embodiment is an adsorption-microwave absorption bifunctional material, which is a mixture of an adsorption component and a microwave absorption component. The adsorption component is 5A molecular sieve, and the microwave absorption component is SiC, with a mass ratio of 1:1. The specific synthesis method is as follows: 5A molecular sieve and SiC are mixed uniformly to obtain the adsorption-microwave absorption bifunctional material.

[0112] The 5A molecular sieve used in the examples was manufactured by 3A Chem, catalog number A17090, and was in powder form; the silicon carbide (SiC) was manufactured by Alfa Aesar, catalog number A14470, and had an average particle size of 300-425 μm.

[0113] The specific steps of the thermogravimetric analysis method for microwave-assisted CO2 capture are as follows:

[0114] 1) After drying the adsorption-absorption dual-functional material in an oven at 100°C for 2 hours, take 1.0 g and place it on the sieve plate of a quartz tube, and record the weighing value of the balance before CO2 adsorption.

[0115] 2) CO2 adsorption: CO2 adsorption is carried out at room temperature (25°C). A mixed gas of CO2 at a flow rate of 50 ml / min and N2 at a flow rate of 50 ml / min is introduced into the inlet of the quartz tube. The mixed gas flows vertically from top to bottom through the adsorption-absorbing dual-functional material to capture CO2 in the simulated flue gas. The adsorbed low-carbon flue gas is discharged through the outlet of the quartz tube and enters the gas analyzer. The real-time weighing value of the balance is recorded. The time resolution of the balance is 0.05 s. The adsorption value is obtained by subtracting the real-time weighing value of the balance before CO2 adsorption in step 1). At the same time, the temperature of the adsorption-absorbing dual-functional material is measured in real time. The adsorption time is set to 15 min.

[0116] 3) CO2 Desorption: In the microwave-assisted reaction unit, the controller turns on the power to energize the magnetron and generate microwaves. The microwave power is set to 500 W and the heating temperature is set to 250°C. The microwaves are conducted through the waveguide to the circulator, processed by the circulator, and then conducted to the microwave cavity. The quartz tube passes vertically through the microwave cavity, and the microwaves act on the adsorption-absorbing dual-functional material through the quartz. At the same time, the circulating water tank is turned on, and circulating water flows through the circulating water pipe. A mixed gas of CO2 at a rate of 50 ml / min and N2 at a rate of 50 ml / min is continuously introduced from the air inlet of the quartz tube. The desorbed gas is discharged through the air outlet of the quartz tube and enters the gas analyzer. The real-time weighing value of the balance is recorded and the adsorption value is calculated. The temperature of the adsorption-absorbing dual-functional material is measured in real time. The desorption time is set to 7.5 min.

[0117] 4) Repeat steps 2) and 3) for 3 cycles.

[0118] 5) Turn off the balance weight recording program, shortwave infrared thermometer, gas analyzer, and power supply to the microwave-assisted reaction unit.

[0119] Testing showed that the microwave-assisted CO2 capture thermogravimetric analysis device of this invention exhibited no gas leakage during CO2 adsorption and desorption processes.

[0120] Plotting time (s) on the x-axis and adsorption value (g) on ​​the y-axis, the data from three cycles were statistically analyzed to create a time-adsorption value curve, as shown below. Figure 4 The weight data from the thermogravimetric system can directly reflect the CO2 capture situation. Figure 4It can be seen that the microwave-assisted CO2 capture thermogravimetric analysis device and method of this invention have fast and efficient adsorption and desorption processes, and still have good stability and strong repeatability after multiple cycle tests.

[0121] It should be noted that although the technical solution of this utility model has been described with specific examples, those skilled in the art will understand that this utility model should not be limited thereto.

[0122] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical applications, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A microwave-assisted thermogravimetric analysis device for carbon dioxide capture, characterized in that, The 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 generating structure, a waveguide, a circulator, and a microwave cavity; the microwave generating structure generates microwaves, which are conducted through the waveguide to the circulator, processed by the circulator, and then conducted to the microwave cavity; The weight recording unit has 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, the fixed-bed reaction tube has an air inlet on its side, one end of the fixed-bed reaction tube is connected to the weight measuring structure, and the other end has an air outlet. The gas analysis unit is connected to the gas outlet of the fixed-bed reaction tube.

2. The thermogravimetric analysis apparatus 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, which is built into the waveguide and connected to the microwave generating structure, the circulator, the microwave cavity and the water load.

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

4. The thermogravimetric analysis apparatus according to claim 1 or 2, characterized in that: The weight measuring structure includes a balance, a wire hanging device, and a flange. The fixed-bed reaction tube is a quartz tube; The fixed-bed reaction tube is equipped with a sieve plate, on which the sample to be tested is placed; 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 apparatus according to claim 1 or 2, characterized in that: The gas mixing structure has a gas distribution box, the gas outlet of which is connected to the gas inlet of the fixed bed reaction tube, and has a built-in flow meter; The gas analysis unit has an air inlet, which is connected to the air outlet of the fixed bed reaction tube. The temperature measuring unit includes an infrared thermometer.

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