Carbon dioxide trapping system and carbon dioxide trapping method

Abstract

The invention belongs to the technical field of carbon dioxide trapping, and particularly relates to a carbon dioxide trapping system and a carbon dioxide trapping method. Compared with a traditional thermal desorption method, the carbon dioxide trapping system based on external microwave field assisted absorbent catalytic desorption has the advantage that the microwave desorption method has higher energy utilization efficiency. The random packing catalyst has an acid catalysis function, so that the desorption amount and the carbon removal rate of the absorbent can be further improved, and the random packing catalyst has a microwave absorption function, so that heat and mass transfer in the desorption process is enhanced in a hot spot form, and the utilization of microwaves is further improved. The desorption efficiency of 60-80% can be achieved below 102 DEG C, the CO2 desorption rate is far higher than that of a traditional thermal desorption method, and latent heat consumed by water evaporation in the desorption process is remarkably reduced. Meanwhile, the CO2 removal efficiency of the absorption tower is improved, and the cost of the whole carbon capture process can be remarkably reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon dioxide capture, and in particular relates to a carbon dioxide capture system and a carbon dioxide capture method. Background Art

[0002] As global CO2 emissions increase, global warming and climate change are exacerbating their impacts. To address this issue, both domestic and international efforts are exploring the use of CO2 capture, utilization, and storage (CCUS) technologies to reduce CO2 emissions while meeting energy needs. CO2 capture refers to the process of separating and collecting CO2 from exhaust gases emitted by emission sources (such as power plants, steel mills, and refineries). It is the foundation and prerequisite for the development of CCUS technology. CO2 capture methods primarily include chemical absorption, physical absorption, and membrane separation. Chemical absorption is currently the most widely used method for CO2 capture. Chemical absorption involves absorption and desorption. The absorption process involves contacting CO2 with a chemical absorbent, absorbing the CO2 into the absorbent. The desorption process involves desorbing the absorbent, which has become saturated with CO2, to achieve regeneration. The traditional desorption process uses steam as a heat source, heating the desorption temperature to 110-130°C for thermal regeneration. Since water accounts for about 50-70% of the absorbent, the invalid heat such as sensible heat and latent heat of water leads to the problems of high energy consumption and low steam utilization rate in the existing carbon capture process. The cost of carbon capture is as high as 400-500 yuan / ton of CO2, which seriously hinders the promotion and application of chemical absorption method. Summary of the Invention

[0003] In view of this, the present invention provides a carbon dioxide capture system and a carbon dioxide capture method. When carbon dioxide is captured using the carbon dioxide capture system provided by the present invention, desorption can be performed at a lower temperature, industrial waste heat can be fully utilized, the capture efficiency can be improved, and the capture cost can be reduced.

[0004] In order to solve the above technical problems, the present invention provides a carbon dioxide capture system, comprising an absorption tower 101 and a desorption unit connected in series with the top of the absorption tower 101 and the bottom of the absorption tower 101, wherein the desorption unit is a thermal desorption tower 501 and a microwave desorption tower 601 connected in series in sequence, or an integrated desorption tower 301;

[0005] A first random packing catalyst 304 and a first waveguide tube 302 are arranged in the kettle of the integrated desorption tower 301, and a first magnetron assembly 303 is arranged on the outer wall of the kettle of the integrated desorption tower 301; a first reboiler 213 is connected in series between the lower part and the bottom of the kettle of the integrated desorption tower 301.

[0006] Preferably, a first filler 307 is provided at the upper and middle parts of the integrated desorption tower 301, and a first spray device 308 is provided at the top inlet of the integrated desorption tower 301;

[0007] The top outlet 306 of the integrated desorption tower 301 is connected in series with the first cooler 214 and the first jet pump 203 in sequence, the gas outlet of the first condenser 214 is connected to the first carbon dioxide collector 401, and the outlet of the first jet pump 203 is connected to the bottom inlet of the integrated desorption tower 301.

[0008] Preferably, a first liquid pump 204 is provided between the bottom of the integrated desorption tower 301 and the first reboiler 213 , and the inlet of the first reboiler 213 is connected to the first industrial waste heat source 305 .

[0009] Preferably, a catalytic module 502 is provided in the kettle of the thermal desorption tower 501;

[0010] A second reboiler 215 and a second liquid pump 206 are connected in series between the lower part and the bottom of the thermal desorption tower 501, and the inlet of the second reboiler 215 is connected to the second industrial waste heat source 506;

[0011] The second filler 504 is provided at the upper and middle parts of the thermal desorption tower 501;

[0012] A second spray device 505 is provided at the top inlet of the thermal desorption tower 501;

[0013] A third liquid pump 205 is connected in series between the bottom outlet of the thermal desorption tower 501 and the top inlet of the microwave desorption tower 601;

[0014] The top outlet of the thermal desorption tower 501 is connected in series with a second cooler 216 .

[0015] Preferably, a second random packing catalyst 311 and a second waveguide tube 309 are provided in the reactor of the microwave desorption tower 601, and a second magnetron assembly 310 is provided on the outer wall of the reactor of the microwave desorption tower 601;

[0016] A third filler 602 is provided at the upper and middle parts of the microwave desorption tower 601, and a third spray device 603 is provided at the top inlet of the microwave desorption tower 601;

[0017] The top outlet of the microwave desorption tower 601 is connected in series to the second cooler 216 ; the liquid outlet of the second cooler 216 is connected to the bottom inlet of the microwave desorption tower 601 by a second jet pump 207 ; the gas outlet of the second condenser 216 is connected to the second carbon dioxide collector 402 .

[0018] Preferably, a fourth filler 102 is provided at the upper and middle parts of the absorption tower 101, and a fourth spray device 103 is provided at the top inlet of the absorption tower 101;

[0019] A gas inlet 104 is provided at the lower portion of the absorption tower 101;

[0020] The bottom outlet of the absorption tower 101 and the liquid inlet of the desorption unit are connected by a fourth liquid pump 201 and a heat exchanger 212;

[0021] The liquid outlet of the desorption unit and the liquid inlet of the absorption tower 101 are connected via a fifth liquid pump 202 , a heat exchanger 212 and a third cooler 211 .

[0022] The present invention also provides a method for capturing carbon dioxide using the carbon dioxide capture system described in the above technical solution, comprising the following steps:

[0023] The gas containing carbon dioxide enters the absorption tower 101 through the gas inlet 104 and is contacted with the absorbent sprayed by the fourth spray device 103 for absorption to obtain a rich phase absorbent;

[0024] The rich phase absorbent is transferred to a desorption unit for sequential thermal desorption and microwave catalytic desorption to obtain a regenerated absorbent and carbon dioxide.

[0025] Preferably, the random packing catalyst for microwave catalytic desorption includes molecular sieve catalysts, alumina catalysts, solid acid metal oxide catalysts, porous carbon or silicon carbide;

[0026] The residence time of the microwave catalytic desorption is 20 to 30 minutes.

[0027] Preferably, the temperature of the thermal desorption is 95 to 102° C., and the retention time of the thermal desorption is 20 to 30 minutes;

[0028] The catalyst module for thermal desorption is composed of a second random packing catalyst 311 and a structured packing.

[0029] Preferably, the absorbent comprises one or more of a primary amine solution, a secondary amine solution and a tertiary amine solution.

[0030] The present invention provides a carbon dioxide capture system, comprising an absorption tower 101 and a desorption unit connected in series with the top of the absorption tower 101 and the bottom of the absorption tower 101. The desorption unit is a thermal desorption tower 501 and a microwave desorption tower 601 connected in series, or an integrated desorption tower 301. The integrated desorption tower 301 has a first random packing catalyst 304 and a first waveguide 302 disposed in the bottom of the tower, and a first magnetron assembly 303 disposed on the outer wall of the bottom of the tower. A first reboiler 213 is connected in series between the lower part and the bottom of the bottom of the tower. The carbon dioxide capture system based on exogenous microwave field-assisted absorber catalytic desorption proposed by the present invention has higher energy utilization efficiency than traditional thermal desorption methods. At the same time, the present invention uses industrial waste heat to reduce the electrical energy consumed by microwaves, and combines the absorbing catalyst (random packing catalyst) to enhance the utilization efficiency of microwave energy, thereby achieving lower desorption energy consumption. The acid catalytic function of the random packing catalyst can further increase the desorption amount and carbon removal rate of the absorbent. In addition, the random packing catalyst has the function of absorbing microwaves, which can enhance the heat and mass transfer of the desorption process in the form of "hot spots", further improving the utilization of microwaves.

[0031] This method can achieve a desorption efficiency of 60-80% below 102°C, significantly exceeding the CO2 desorption rate of traditional thermal desorption methods and significantly reducing the latent heat consumed by water evaporation during the desorption process. It also improves the CO2 removal efficiency of the absorption tower, significantly reducing the cost of the overall carbon capture process. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the system structure used for carbon dioxide capture in Example 1;

[0033] Figure 2 This is a schematic diagram of the system structure used for carbon dioxide capture in Example 2;

[0034] Figure 1 and Figure 2101 is an absorption tower, 102 is a fourth filler, 103 is a fourth spray device, 104 is a gas inlet, 105 is a smoke outlet, 201 is a fourth liquid pump, 202 is a fifth liquid pump, 203 is a first jet pump, 204 is a first liquid pump, 205 is a third liquid pump, 206 is a second liquid pump, 207 is a second jet pump, 211 is a third cooler, 212 is a heat exchanger, 213 is a first reboiler, 214 is a first cooler, 215 is a second reboiler, 216 is a second cooler, 301 is an integrated desorption tower, 302 is a first waveguide, 303 is a first magnetron assembly, 304 is a first bulk filler The catalyst is a material, 305 is a first industrial waste heat source, 306 is a top outlet of an integrated desorption tower, 307 is a first filler, 308 is a first spray device, 309 is a second waveguide, 310 is a second magnetron assembly, 311 is a second random packing catalyst, 401 is a first carbon dioxide collector, 402 is a second carbon dioxide collector, 501 is a thermal desorption tower, 502 is a catalytic module, 503 is a gas outlet of the thermal desorption tower, 504 is a second filler, 505 is a second spray device, 601 is a microwave desorption tower, 602 is a third filler, 603 is a third spray device, and 604 is a top outlet of the microwave desorption tower;

[0035] Figure 3 is a schematic structural diagram of the catalytic module 502;

[0036] Figure 4 The graph of the carbon dioxide desorption amount over time for Example 1, Example 2, Comparative Example 1 and Comparative Example 2 within 1 hour of desorption is shown;

[0037] Figure 5 The graph shows the change of CO2 loading of the absorbent over time under direct microwave heating and microwave heating catalytic CO2 desorption within 1 hour under the premise of adding silicon carbide catalyst;

[0038] Figure 6 This is a curve of temperature change over time during 10 minutes of microwave catalytic CO2 desorption under direct microwave heating and microwave heating with the addition of silicon carbide catalyst. DETAILED DESCRIPTION

[0039] The present invention provides a carbon dioxide capture system, comprising an absorption tower 101 and a desorption unit connected in series with the top of the absorption tower 101 and the bottom of the absorption tower 101. The desorption unit is a thermal desorption tower 501 and a microwave desorption tower 601 connected in series or an integrated desorption tower 301.

[0040] As a specific embodiment of the present invention, a fourth filler 102 is provided at the upper and middle parts of the absorption tower 101 , and the fourth filler 102 may be a 314 stainless steel θ ring.

[0041] As a specific embodiment of the present invention, a fourth spray device 103 is provided at the top inlet of the absorption tower 101; a gas inlet 104 is provided at the lower part of the absorption tower 101; the liquid outlet of the desorption unit and the liquid inlet of the absorption tower 101 are connected by a fifth liquid pump 202, a heat exchanger 212 and a third cooler 211, and the bottom outlet of the absorption tower 101 and the liquid inlet of the desorption unit are connected by a fourth liquid pump 201 and a heat exchanger 212; specifically, the bottom outlet of the microwave desorption tower 601 and the top inlet of the thermal desorption tower 501 are connected by a fifth liquid pump 202 and a heat exchanger 212, or specifically, the bottom outlet of the integrated desorption tower 301 and the top inlet of the integrated desorption tower 301 are connected by a fifth liquid pump 202 and a heat exchanger 212.

[0042] In the present invention, a first random packing catalyst 304 and a first waveguide tube 302 are provided in the kettle of the integrated desorption tower 301, and a first magnetron assembly 303 is provided on the outer wall of the kettle of the integrated desorption tower 301; a first reboiler 213 is connected in series between the lower part and the bottom of the kettle of the integrated desorption tower 301. In the present invention, the microwave generator is composed of a first magnetron assembly 303 and a first waveguide tube 302, the first magnetron assembly 303 is a microwave generating source, the first waveguide tube 302 evenly distributes microwaves in the reaction chamber, and the outer layer of the first waveguide tube 302 can be wrapped with a Teflon sleeve to prevent the waveguide tube from contacting the liquid. As a specific embodiment of the present invention, the first random packing catalyst 304 can be a molecular sieve catalyst, an alumina catalyst, a solid acid metal oxide catalyst, porous carbon or silicon carbide.

[0043] As a specific embodiment of the present invention, a first filler 307 is provided at the upper and middle portions of the integrated desorption tower 301. The first filler 307 may be a 314 stainless steel theta ring. As a specific embodiment of the present invention, a first spray device 308 is provided at the top inlet of the integrated desorption tower 301. The top outlet 306 of the integrated desorption tower 301 is sequentially connected in series with a first cooler 214 and a first jet pump 203. The gas outlet of the first condenser 214 is connected to a first carbon dioxide collector 401. The outlet of the first jet pump 203 is connected to the bottom inlet of the integrated desorption tower 301. The present invention stirs the first random packing catalyst 304 by the first jet pump 203, which facilitates microwave catalytic desorption.

[0044] As a specific embodiment of the present invention, a first liquid pump 204 is disposed between the bottom of the integrated desorption tower 301 and the first reboiler 213. The inlet of the first reboiler 213 is connected to a first industrial waste heat source 305. The present invention utilizes the first liquid pump 204 to pass the carbon dioxide-absorbent-rich phase into the reboiler 213 for thermal desorption before returning it to the integrated desorption tower 301. As a specific embodiment of the present invention, the first industrial waste heat source 305 may be industrial waste heat steam or industrial waste hot water. The temperature of the first industrial waste heat source 305 may be between 95°C and 102°C, specifically 95°C, 98°C, 100°C, or 102°C.

[0045] The steam (CO2+H2O) generated during the desorption process in the integrated desorption tower 301 of the present invention is heat exchanged through the first filler 307 and discharged through the top outlet 306 of the integrated desorption tower 301. The steam passes through the first cooler 214 to separate H2O and CO2. The first jet pump 203 returns the condensed water obtained by condensation to the integrated desorption tower 301 in the form of a jet, and at the same time stirs the absorbent and the first random packing catalyst 304 to achieve uniform heating of the materials; the lean phase absorbent after desorption and regeneration is returned to the top liquid inlet of the absorption tower 101 via the fifth liquid pump 202 and the heat exchanger 212, and is cooled by the third cooler 211; the condensed and separated carbon dioxide will enter the first carbon dioxide collector 401 through the gas outlet of the first cooler 214.

[0046] As a specific embodiment of the present invention, the desorption unit is a thermal desorption tower 501 and a microwave desorption tower 601 connected in series in sequence, and a catalytic module 502 is provided in the kettle of the thermal desorption tower 501; a second reboiler 215 and a second liquid pump 206 are connected in series between the lower part and the bottom of the kettle of the thermal desorption tower 501, and the inlet of the second reboiler 215 is connected to the second industrial waste heat source 506; a second filler 504 is provided in the upper and middle parts of the thermal desorption tower 501, and the second filler 504 can be a 314 stainless steel θ ring; a second spray device 505 is provided at the top inlet of the thermal desorption tower 501; a third liquid pump 205 is connected in series between the bottom outlet of the thermal desorption tower 501 and the top inlet of the microwave desorption tower 601; and a second cooler 216 is connected in series with the top outlet of the thermal desorption tower 501. In the present invention, the catalyst in the catalytic module 502 can be composed of a second random packing catalyst 311 and a structured packing. The catalytic module can catalyze the desorption of the absorbent, while optimizing the heat and mass transfer of the thermal desorption tower to increase the desorption amount of the absorbent. Figure 3 Schematic diagram of the structure of the catalytic module 502.

[0047] As a specific embodiment of the present invention, a second random packing catalyst 311 and a second waveguide tube 309 are arranged in the kettle of the microwave desorption tower 601, and a second magnetron assembly 310 is arranged on the outer wall of the kettle of the microwave desorption tower 601; a third filler 602 is arranged in the upper and middle parts of the microwave desorption tower 601, and the third filler 602 can be a 314 stainless steel θ ring; a third spray device 603 is arranged at the top inlet of the microwave desorption tower 601; the top outlet 604 of the microwave desorption tower is connected in series with a second cooler 216; the liquid outlet of the second cooler 216 and the bottom inlet of the microwave desorption tower 601 are connected by a second jet pump 207; the gas outlet of the second condenser 216 is connected to the second carbon dioxide collector 402.

[0048] When the desorption unit is a thermal desorption tower 501 and a microwave desorption tower 601 connected in series, the desorption process is specifically as follows: after absorbing carbon dioxide, the rich phase absorbent enters the thermal desorption tower 501, undergoes thermal desorption under the catalytic action of the catalytic module 502 and is converted into a primary lean phase absorbent, and the desorbed gas is discharged from the thermal desorption tower outlet 503; the primary lean phase absorbent flows out from the bottom of the thermal desorption tower 501 through the third liquid pump 205 and enters the microwave desorption tower 601, undergoes microwave catalytic desorption under the action of microwaves and the second random packing catalyst 311, and the primary lean phase absorbent is converted into a secondary lean phase absorbent. The secondary lean phase absorbent passes through the second liquid pump 202, the heat exchanger 212 and the third cooler 211 and enters the liquid inlet of the absorption tower 101.

[0049] The present invention also provides a method for capturing carbon dioxide using the carbon dioxide capture system described in the above technical solution, comprising the following steps:

[0050] The gas containing carbon dioxide enters the absorption tower 101 through the gas inlet 104 and is contacted with the absorbent sprayed by the fourth spray device 103 for absorption to obtain a rich phase absorbent;

[0051] The rich phase absorbent is transferred to a desorption unit for sequential thermal desorption and microwave catalytic desorption to obtain a regenerated absorbent and carbon dioxide.

[0052] The present invention allows gas containing carbon dioxide to enter the absorption tower 101 through the gas inlet 104 and contact with the absorbent sprayed by the fourth spray device 103 for absorption, thereby obtaining a rich-phase absorbent. As a specific embodiment of the present invention, the flow rate of the gas containing carbon dioxide entering the absorption tower 101 can be 250 to 1000 mL / min, specifically 250 mL / min, 270 mL / min, 300 mL / min, 500 mL / min, or 1000 mL / min; the absorbent can include one or more of a primary amine solution, a secondary amine solution, and a tertiary amine solution, specifically ethanolamine, diethanolamine, or N-methyldiethanolamine; the molar concentration of the absorbent can be 4.5 to 5.5 mol / L, specifically 4.5 mol / L, 5 mol / L, or 5.5 mol / L; the flow rate of spraying the absorbent can be 7 to 16 mL / min, specifically 7 mL / min, 10 mL / min, 13 mL / min, or 16 mL / min.

[0053] After obtaining the rich-phase absorbent, the present invention transfers the rich-phase absorbent to a desorption unit for sequential thermal desorption and microwave catalytic desorption to obtain a regenerated absorbent and carbon dioxide. In a specific embodiment of the present invention, the thermal desorption temperature can be 95 to 102°C, specifically 95°C, 98°C, 100°C, or 102°C; and the retention time of the thermal desorption can be 20 to 30 minutes, specifically 20 minutes, 25 minutes, or 30 minutes.

[0054] As a specific embodiment of the present invention, the random packing catalyst for microwave catalytic desorption may include a molecular sieve catalyst, an alumina catalyst, a solid acid metal oxide catalyst, porous carbon or silicon carbide; the mass ratio of the random packing catalyst to the multiphase absorber may be 1g:180~220mL, specifically 1g:200mL; the microwave power of the microwave catalytic desorption may be 230~250W, specifically 230W, 235W, 240W, 245W or 250W, and the residence time of the microwave catalytic desorption may be 20~30min, specifically 20min, 25min or 30min.

[0055] Microwaves, as a type of electromagnetic energy between infrared and radio waves, can irradiate polar molecules, causing intramolecular oscillations to release intramolecular energy and heat the reaction system. At the same time, the polarization effect of microwaves can induce chemical bonds to stretch and break, which can greatly improve the efficiency and material yield of thermal catalytic reactions. Since the absorbent in the carbon capture system is a polar species, microwaves can heat the absorbent to the target temperature while utilizing the polarization induction effect on the absorbent molecules to reduce the reaction energy barrier of CO2 desorption and increase the CO2 desorption rate. Therefore, under the condition of the same CO2 desorption rate, the desorption temperature under microwave action is lower. The carbon dioxide capture method provided by the present invention makes full use of the waste heat generated by the industrial production process, reduces the power consumption of the microwave device, and utilizes the characteristics of microwave heating at the molecular level to increase the desorption rate and desorption amount of the absorbent at low temperatures, effectively reducing the energy consumption of the desorption process.

[0056] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0057] Example 1

[0058] Use Figure 1 The carbon dioxide capture system when the desorption unit is an integrated desorption tower 301 captures carbon dioxide:

[0059] Simulated flue gas (CO2 volume concentration of 15%, the rest of the gas is N2) enters the absorption tower 101 at a rate of 1 L / min through the gas inlet 104. The simulated flue gas is in reverse contact with the lean phase absorbent ethanolamine solution (molar concentration of 5 mol / L, spray flow rate of 16 mL / min) sprayed into the absorption tower 101 via the filler 102 (314 stainless steel θ ring) to absorb the carbon dioxide in the flue gas, thereby obtaining a rich phase absorbent.

[0060] The decarbonized flue gas is discharged from the exhaust port 105 of the absorption tower 101, and the rich phase absorbent is transported from the liquid outlet at the bottom of the absorption tower 101 to the integrated desorption tower 301 via the fourth liquid pump 201 and the heat exchanger 212 for spraying by the first spraying device 308. After being cooled by the first filler 307 (314 stainless steel θ ring), it enters the tower kettle. The rich phase absorbent is transported to the first reboiler 213 (introducing industrial waste heat to provide 102°C) under the action of the first liquid pump 204 for thermal desorption (residence time is 25min) and then refluxed to the tower kettle of the integrated desorption tower 301. Under the action of the first random packing catalyst 304 (silicon carbide), the first waveguide tube 302 and the first magnetron assembly 303, microwave heating is carried out at a power of 240W, a frequency of 2.45GHz and a temperature of 102°C. Catalytic desorption (residence time is 25 minutes); the steam (CO2+H2O) generated by microwave catalytic desorption passes through the first filler 307 for heat exchange and is discharged through the top outlet 306 of the integrated desorption tower. The steam passes through the first cooler 214 to separate H2O and CO2. The first jet pump 203 returns the condensed water obtained by condensation to the integrated desorption tower 301 in the form of a jet, while stirring the absorbent and the first random packing catalyst 304; the lean phase absorbent after desorption and regeneration returns to the top liquid inlet of the absorption tower 101 via the fifth liquid pump 202 and the heat exchanger 212, and is cooled by the third cooler 211; the condensed and separated carbon dioxide will enter the first carbon dioxide collector 401 through the gas outlet of the first cooler 214, completing the absorption-desorption cycle.

[0061] Example 2

[0062] Use Figure 2 The carbon dioxide capture system in which the desorption unit is a thermal desorption tower 501 and a microwave desorption tower 601 connected in series captures carbon dioxide:

[0063] Simulated flue gas (CO2 volume concentration of 15%, the rest of the gas is N2) enters the absorption tower 101 at a rate of 1 L / min through the gas inlet 104. The simulated flue gas is in reverse contact with the lean phase absorbent ethanolamine solution (molar concentration of 5 mol / L, spray flow rate of 16 mL / min) sprayed into the absorption tower 101 via the filler 102 (314 stainless steel θ ring) to absorb the carbon dioxide in the flue gas, thereby obtaining a rich phase absorbent.

[0064] The decarbonized flue gas is discharged from the exhaust port 105 of the absorption tower 101. The rich phase absorbent is transported from the liquid outlet at the bottom of the absorption tower 101 via the fourth liquid pump 201 and the heat exchanger 212 to the thermal desorption tower 501 for spraying by the second spray device 505. After cooling by the second filler 504 (314 stainless steel θ ring), it is thermally desorbed at 102°C under the action of the catalytic module 502 (the catalyst is silicon carbide and the filler is a monolithic filler) and industrial waste heat gas. The desorbed gas is discharged from the gas outlet at the top of the thermal desorption tower, condensed by the second condenser 216, and then enters the second carbon dioxide collector 402. The first lean phase absorbent generated after thermal desorption is transported by the third liquid pump 205 to the microwave desorption tower 601, sprayed by the third spray device 603, and cooled by contact with the third filler 602 (314 stainless steel θ ring). After cooling, it enters the tower kettle and enters the second random packing catalyst 311 (silicon carbide). , the second waveguide 309 and the second magnetron assembly 310 perform microwave catalytic desorption at 240W and 102°C; the steam (CO2+H2O) generated by microwave catalytic desorption passes through the third filler 602 for heat exchange and is discharged through the top outlet 604 of the microwave desorption tower 601. The steam passes through the second cooler 216 to separate H2O and CO2. The second jet pump 207 refluxes the condensed water obtained by condensation to the microwave desorption tower 601 in the form of a jet, while stirring the absorbent and the second random packing catalyst 311; the secondary lean phase absorbent after desorption and regeneration is returned to the top liquid inlet of the absorption tower 101 via the fifth liquid pump 202 and the heat exchanger 212, and is cooled by the third cooler 211; the condensed and separated carbon dioxide enters the second carbon dioxide collector 402 through the gas outlet of the second cooler 216, completing the absorption-desorption cycle.

[0065] Comparative Example 1

[0066] Carbon dioxide capture was carried out according to the method of Example 1, except that the microwave generator was not turned on, that is, only thermal desorption was carried out.

[0067] Comparative Example 2

[0068] Carbon dioxide capture was carried out according to the method of Example 1, except that no random packing catalyst was added during microwave desorption.

[0069] The flow rate of carbon dioxide entering the carbon dioxide collector was monitored by a mass flow meter, and the desorption amount of carbon dioxide and the carbon removal rate (the ratio of the carbon dioxide desorption amount to the CO2 content in the flue gas) were calculated. The graph of the carbon dioxide desorption amount over time in Examples 1-2 and Comparative Examples 1-2 within 1 hour of desorption is shown in Figure 2. Figure 4 The results of carbon dioxide desorption amount and removal rate of Examples 1-2 and Comparative Examples 1-2 are listed in Table 1.

[0070] Table 1 Carbon dioxide desorption amount and carbon removal rate of Examples 1-2 and Comparative Examples 1-2

[0071] Example <![CDATA[Amount of desorbed CO2 per hour, mol CO2 / L]]> Average carbon removal rate in 1h% <![CDATA[Energy consumption GJ / tCO2]]> Example 1 0.871 80.32 1.96 Example 2 0.833 78.31 2.05 Comparative Example 1 0.235 36.90 3.21 Comparative Example 2 0.571 53.28 2.58

[0072] According to Table 1 and Figure 4 It can be seen that, combined with the results of Comparative Example 1 and Comparative Example 2, it can be seen that the introduction of microwave-assisted microwave catalytic desorption increases the carbon dioxide desorption amount by 143% in 1 hour, the average carbon removal rate in 1 hour is increased to 53.28%, and the energy consumption of Comparative Example 2 is reduced by 19.63% compared with Comparative Example 1. Combining the results of Example 1 and Comparative Example 1, it can be seen that the carbon dioxide desorption amount of the combination of thermal desorption and microwave catalytic desorption is increased by 271% compared with thermal catalytic desorption alone, the average carbon removal rate in 1 hour is increased to 80.32%, and the energy consumption of Example 1 is reduced by 38.94% compared with Comparative Example 1. Combining the results of Example 1 and Comparative Example 2, it can be seen that the addition of catalyst in microwave-assisted microwave catalytic desorption operation increases the carbon dioxide desorption amount by 52.54%, and the energy consumption of Example 1 is reduced by 24.03% compared with Comparative Example 2.

[0073] The catalytic performance test of SiC powder under microwave is as follows: Scheme 1: add 1g SiC to 200mL of saturated MEA solution with a molar concentration of 5mol / L to obtain a saturated absorbent containing catalytic material, and add the solution to a three-necked flask in the microwave desorber cavity; Scheme 2: directly add 200mL of saturated MEA solution with a molar concentration of 5mol / L to the three-necked flask in the microwave desorber cavity for microwave desorption; the outlet CO2 flow rate is monitored by a flow meter; the microwave power is 240W, and the desorption temperature is controlled at 90℃; the test results are shown in Figure 5 and Figure 6 ,according to Figure 5 and Figure 6 The calculated results of carbon dioxide desorption amount and heating rate are listed in Table 2.

[0074] Table 2 Carbon dioxide desorption amount and heating rate under different conditions

[0075]

[0076] Combined with Table 2 and Figure 5 It can be seen that the addition of SiC to the microwave desorption device increases the desorption amount by 30.89%.

[0077] Combined with Table 2 and Figure 6 It can be seen that SiC can accelerate the temperature rise of the system and improve the utilization of microwave energy. Specifically, SiC increases the heating rate by 30.48%. This is because SiC has good microwave absorption and excellent thermal conductivity. It can generate "hot spots" in the microwave environment, further enhancing the heat and mass transfer of the system.

[0078] When SiC was immersed in a MEA solution with a molar concentration of 5 mol / L at 120°C for 144 hours, the Si leaching rate was 0.09%, which shows that SiC has good stability in the MEA solution.

[0079] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A carbon dioxide capture system, characterized in that: It comprises an absorption tower (101) and a desorption unit whose top is connected in series with the bottom of the absorption tower (101), wherein the desorption unit is a thermal desorption tower (501) and a microwave desorption tower (601) connected in series in sequence or an integrated desorption tower (301); A first random packing catalyst (304) and a first waveguide tube (302) are arranged in the kettle of the integrated desorption tower (301), and a first magnetron assembly (303) is arranged on the outer wall of the kettle of the integrated desorption tower (301); and a first reboiler (213) is connected in series between the lower part and the bottom of the kettle of the integrated desorption tower (301).

2. The carbon dioxide capture system according to claim 1, characterized in that: A first filler (307) is provided at the upper and middle parts of the integrated desorption tower (301), and a first spraying device (308) is provided at the top inlet of the integrated desorption tower (301); The top outlet (306) of the integrated desorption tower (301) is connected in series with the first cooler (214) and the first jet pump (203), the gas outlet of the first condenser (214) is connected to the first carbon dioxide collector (401), and the outlet of the first jet pump (203) is connected to the bottom inlet of the integrated desorption tower (301).

3. The carbon dioxide capture system according to claim 1 or 2, characterized in that: A first liquid pump (204) is provided between the kettle of the integrated desorption tower (301) and the first reboiler (213), and the inlet of the first reboiler (213) is connected to a first industrial waste heat source (305).

4. The carbon dioxide capture system according to claim 1, characterized in that: A catalytic module (502) is provided in the kettle of the thermal desorption tower (501); A second reboiler (215) and a second liquid pump (206) are connected in series between the lower part and the bottom of the kettle of the thermal desorption tower (501), and the inlet of the second reboiler (215) is connected to a second industrial waste heat source (506); A second filler (504) is provided at the upper and middle parts of the thermal desorption tower (501); A second spraying device (505) is provided at the top inlet of the thermal desorption tower (501); A third liquid pump (205) is connected in series between the bottom outlet of the thermal desorption tower (501) and the top inlet of the microwave desorption tower (601); The top outlet of the thermal desorption tower (501) is connected in series with a second cooler (216).

5. The carbon dioxide capture system according to claim 1, characterized in that: A second random packing catalyst (311) and a second waveguide tube (309) are arranged in the microwave desorption tower (601) kettle, and a second magnetron assembly (310) is arranged on the outer wall of the microwave desorption tower (601) kettle; A third filler (602) is provided at the upper and middle parts of the microwave desorption tower (601), and a third spraying device (603) is provided at the top inlet of the microwave desorption tower (601); The top outlet of the microwave desorption tower (601) is connected in series to a second cooler (216); the liquid outlet of the second cooler (216) and the bottom inlet of the microwave desorption tower (601) are connected by a second jet pump (207); and the gas outlet of the second condenser (216) is connected to a second carbon dioxide collector (402).

6. The carbon dioxide capture system according to claim 1, characterized in that: A fourth filler (102) is provided at the upper and middle parts of the absorption tower (101), and a fourth spray device (103) is provided at the top inlet of the absorption tower (101); A gas inlet (104) is provided at the lower portion of the absorption tower (101); The bottom outlet of the absorption tower (101) and the liquid inlet of the desorption unit are connected via a fourth liquid pump (201) and a heat exchanger (212); The liquid outlet of the desorption unit and the liquid inlet of the absorption tower (101) are connected via a fifth liquid pump (202), a heat exchanger (212) and a third cooler (211).

7. A method for capturing carbon dioxide using the carbon dioxide capture system according to any one of claims 1 to 6, comprising the following steps: The gas containing carbon dioxide enters the absorption tower (101) through the gas inlet (104) and is contacted with the absorbent sprayed by the fourth spray device (103) for absorption to obtain a rich phase absorbent; The rich phase absorbent is transferred to a desorption unit for sequential thermal desorption and microwave catalytic desorption to obtain a regenerated absorbent and carbon dioxide.

8. The method for capturing carbon dioxide using the carbon dioxide capture system according to any one of claims 1 to 6 according to claim 7, characterized in that: The random packing catalyst used for microwave catalytic desorption includes molecular sieve catalysts, alumina catalysts, solid acid metal oxide catalysts, porous carbon or silicon carbide; The residence time of the microwave catalytic desorption is 20 to 30 minutes.

9. The method for capturing carbon dioxide using the carbon dioxide capture system according to any one of claims 1 to 6 according to claim 7, characterized in that: The temperature of the thermal desorption is 95 to 102° C., and the retention time of the thermal desorption is 20 to 30 minutes; The catalyst for thermal desorption is composed of a second random packing catalyst (311) and a structured packing.

10. The method for capturing carbon dioxide using the carbon dioxide capture system according to any one of claims 1 to 6 according to claim 7, characterized in that: The absorbent includes one or more of a primary amine solution, a secondary amine solution and a tertiary amine solution.

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