A novel carbon dioxide absorbent and capture system

Abstract

The application relates to the technical field of carbon dioxide absorption, and discloses a novel carbon dioxide absorbent and a capturing system, the absorbent comprising 2-aminyl-2-methyl-1-propanol AMP, an activator and a solvent; the capturing system comprising an absorption tower, a solid-liquid separator and a desorption tower, the liquid inlet end of the solid-liquid separator being connected with the liquid outlet of the absorption tower through a conveying pipeline, and the rich-phase inlet end of the desorption tower being connected with the concentrated slurry discharge end through a conveying pipeline. The CO2 absorbent can efficiently realize the absorption and desorption of CO2, and is convenient for recycling; the capturing system can realize the absorption and solidification of CO2 by the CO2 absorbent, solid-liquid two-phase separation and desorption regeneration, can greatly reduce the regeneration volume of the CO2 absorbent, and further reduce the regeneration energy consumption; the CO2 rich-phase slurry after desorption can be converted into liquid phase, and the CO2 absorbent lean liquid separated from the solid-liquid separator is mixed and re-conveyed into the absorption tower to realize recycling absorption and utilization.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide absorption technology, and in particular to a novel carbon dioxide absorbent and capture system. Background Technology

[0002] With the increase in global CO2 emissions, the impacts of global warming and climate change are being exacerbated. To address this issue, domestic and international researchers are exploring the use of CO2 capture, utilization, and storage (CCUS) technologies to reduce CO2 emissions while meeting energy demands. CO2 capture refers to the process of separating and collecting CO2 from exhaust gases emitted from emission sources (such as power plants, steel mills, and oil refineries). It is the foundation and prerequisite for the development of CCUS technology. The main methods of CO2 capture include chemical absorption, physical absorption, and membrane separation. Among these, chemical absorption involves contacting CO2 with a chemical absorbent, absorbing the CO2 into the absorbent, and is currently the most widely used method for CO2 capture.

[0003] Currently, organic amine solutions (such as ethanolamine) are the main absorbents for CO2 capture. After absorbing CO2, the organic amine solution forms a CO2-rich solution, which then enters a stripping column for heating and decomposition to release CO2, resulting in a CO2-lean solution. This solution is then recycled to absorb CO2 again, and the released CO2 is collected and utilized. However, when organic amine solutions are used as CO2 absorbents, they form a saturated phase solution after absorbing CO2. This saturated phase solution requires complete regeneration, leading to high energy consumption during regeneration. This increases the processing cost of the CO2 capture system and makes it difficult to meet the requirements of green and environmentally friendly production. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide a novel carbon dioxide absorbent and capture system to solve the problems of high energy consumption and high cost in the CO2 absorption process.

[0005] Technical solution: The present invention provides a novel carbon dioxide absorbent, wherein the absorbent comprises 2-amino-2-methyl-1-propanol (AMP), an activator, and a solvent;

[0006] The AMP content accounts for 60% of the total volume of the absorbent, and the activator and solvent content accounts for 40% of the total volume of the absorbent.

[0007] The volume ratio of the activator to the solvent is 1:(2~7).

[0008] Preferably, the activator is pentamethyldiethylenetriamine (PMDETA).

[0009] Preferably, the solvent is one or a combination of ethanol, propanol, polyethylene glycol PEG200, and 1,4-butanediol BDO.

[0010] Preferably, the activator is PMDETA, the solvent is propanol, and the volume ratio of PMDETA to propanol is 1:2.

[0011] The present invention also discloses a carbon dioxide capture system, the capture system comprising:

[0012] An absorption tower, wherein the absorption tower is provided with an air inlet, an air outlet, a liquid inlet, and a liquid outlet;

[0013] A solid-liquid separator is provided, wherein the inlet of the solid-liquid separator is connected to the outlet of the absorption tower via a conveying pipeline, and a conveying pump is connected to the conveying pipeline; the solid-liquid separator is provided with a liquid outlet and a slurry outlet.

[0014] The desorption tower is equipped with a reflux end, a rich phase inlet end, and an exhaust end. The rich phase inlet end is connected to the concentrated slurry discharge end through a conveying pipeline, which is connected to a heater and a heat exchanger. The reflux end is connected to the liquid inlet of the absorption tower through a reflux pipe, which is connected to the heat exchanger and the liquid discharge end of the solid-liquid separator, and a cooler is connected to the reflux pipe.

[0015] Preferably, the desorption tower is equipped with a flash evaporator and a compressor, wherein the flash evaporator is connected to the compressor and supplies heat to the desorption tower.

[0016] Preferably, a heat recovery mechanism is provided at the top of the exhaust end of the desorption tower, the heat recovery mechanism comprising:

[0017] An exhaust pipe, which is fixedly connected to the exhaust end;

[0018] A heat exchange tube, which is made of a thermally conductive metal material and is connected to the exhaust pipe;

[0019] A heat-insulating shell is fixedly fitted outside the heat exchange tube, and heat exchange fluid is filled between the heat-insulating shell and the heat exchange tube. A liquid level sensor and a temperature sensor are provided on the inner wall of the heat-insulating shell, and a filling pipe and a drain pipe are connected to the outer wall of the heat-insulating shell. The filling pipe is connected to the water supply end, and the drain pipe is connected to the liquid storage tank. Both the filling pipe and the drain pipe are equipped with control valves.

[0020] Preferably, the heat exchange tube is provided with a heat exchange hollow plate, and two connecting plates are symmetrically connected to both ends of the heat exchange hollow plate. The connecting plates are connected to the outer wall of the heat exchange tube and immersed in the heat exchange liquid. A rotating shaft is provided in the cavity of the heat exchange hollow plate and is rotatably supported on the two connecting plates. Blades are connected to the rotating shaft on the side wall inside the heat exchange hollow plate, and a stirring blade is connected to the outer end of the rotating shaft in the heat exchange liquid. Multiple sets of through holes are respectively provided on the upper and lower surfaces of the heat exchange hollow plate.

[0021] Preferably, a partition is provided inside the heat exchange tube on the upper side of the heat exchange hollow plate, and a plurality of vent holes are provided through the partition; a sliding rod is vertically slidably connected to the partition, a cover plate is connected to the top of the sliding rod, the cover plate is fastened to the partition and can block the vent holes, a load plate is connected to the bottom of the sliding rod, and a load block is connected to the lower end of the load plate.

[0022] Preferably, two hollow tubes are horizontally slidably connected to the two side walls of the heat exchange tube, the outer end of the hollow tube can slide into the heat exchange liquid, and a limit ring is connected to the side wall of the hollow tube located in the heat exchange liquid.

[0023] A linkage ring is provided below the load-bearing block. The linkage ring is fixedly connected to the inner wall of the heat exchange tube by a fixing rod. The linkage ring has a cavity, and a linkage rope is horizontally arranged through the cavity. The two ends of the linkage rope are fixedly connected to one end of the inner side of the hollow tube.

[0024] A pull rope is connected to the weight block, and the lower end of the pull rope is connected to the center of the linkage rope.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The CO2 absorbent of the present invention can efficiently absorb and desorb CO2, and facilitates the recycling of the CO2 absorbent;

[0027] 2. The capture system of the present invention absorbs and solidifies CO2 with a CO2 absorbent, then separates the solid and liquid phases through a solid-liquid separator, and regenerates the concentrated slurry that has absorbed CO2 through thermal decomposition in a desorption tower. This can significantly reduce the regeneration volume of the CO2 absorbent, thereby reducing regeneration energy consumption. After desorption, the CO2-rich slurry can be converted into a liquid phase and mixed with the lean CO2 absorbent solution separated by the solid-liquid separator before being recycled back into the absorption tower for absorption.

[0028] 3. The desorption tower is equipped with a heat recovery mechanism to recover the heat of the high-heat CO2 gas discharged from the desorption tower, thereby avoiding the waste of heat from the emitted CO2 gas and improving the environmental protection production effect of the capture system. Attached Figure Description

[0029] Figure 1 The graphs showing the relationship between CO2 absorbent load and time in Examples 1-4 of the present invention are shown.

[0030] Figure 2 The bar chart shows the CO2 content of the CO2 absorbent solids in Examples 1-4 of this invention.

[0031] Figure 3 The graphs show the relationship between the desorption efficiency of the CO2 absorbent and time in Examples 1-4 of the present invention.

[0032] Figure 4 This is a schematic diagram of the CO2 capture system flow structure of the present invention;

[0033] Figure 5 for Figure 4 Schematic diagram of the three-dimensional structure of the desorption tower and its upper heat recovery mechanism;

[0034] Figure 6 for Figure 5 Cross-sectional view of the heat recovery mechanism along its central longitudinal structure;

[0035] Figure 7 for Figure 6 Enlarged structural diagram at point A in the middle;

[0036] Figure 8 for Figure 6 Enlarged structural diagram at point B;

[0037] Figure 9 for Figure 6 Enlarged structural diagram at point C.

[0038] Figure label:

[0039] 1. Absorption tower; 11. Air inlet; 12. Air outlet; 13. Liquid inlet; 14. Liquid outlet;

[0040] 2. Transfer pump;

[0041] 3. Solid-liquid separator; 31. Liquid discharge end; 32. Thick slurry discharge end; 33. Thick slurry conveying pipeline;

[0042] 4. Heater; 5. Heat exchanger;

[0043] 6. Desorption tower; 61. Reflux end; 62. Rich phase inlet end; 63. Exhaust end;

[0044] 7. Flash evaporator; 8. Compressor;

[0045] 9. Return pipe; 91. Cooler;

[0046] 10. Heat recovery mechanism; 101. Insulated shell; 102. Exhaust pipe; 103. Heat exchange tube; 104. Heat exchange fluid; 105. Hollow heat exchange plate; 106. Connecting plate; 107. Through hole; 108. Rotating shaft; 109. Blade; 110. Stirring blade; 111. Partition plate; 112. Vent hole; 113. Slide rod; 114. Cover plate; 115. Loading plate; 116. Loading block; 117. Hollow tube; 118. Linkage ring; 119. Cavity; 120. Pull rope; 121. Linkage rope; 122. Limiting ring; 123. Liquid level sensor; 125. Temperature sensor; 126. Filling pipe; 127. Drain pipe. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will be described in conjunction with the accompanying drawings of the embodiments of the present invention. Figure 1-9 The technical solutions of the embodiments of the present invention will be clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0048] Example 1:

[0049] This embodiment discloses a novel CO2 absorbent, which includes 2-amino-2-methyl-1-propanol (AMP), an activator, and a solvent. The activator is pentamethyldiethylenetriamine (PMDETA), the solvent is propanol, the AMP content accounts for 60% of the total volume of the absorbent, and the activator and solvent content accounts for 40% of the total volume of the absorbent. The volume ratio of the activator to the solvent is 1:2.

[0050] Example 2:

[0051] This embodiment discloses a novel CO2 absorbent, which includes 2-amino-2-methyl-1-propanol (AMP), an activator, and a solvent. The activator is pentamethyldiethylenetriamine (PMDETA), the solvent is ethanol, the AMP content accounts for 60% of the total volume of the absorbent, and the activator and solvent content accounts for 40% of the total volume of the absorbent. The volume ratio of the activator to the solvent is 1:3.3.

[0052] Example 3:

[0053] This embodiment discloses a novel CO2 absorbent, which includes 2-amino-2-methyl-1-propanol (AMP), an activator, and a solvent. The activator is pentamethyldiethylenetriamine (PMDETA), the solvent is polyethylene glycol (PEG200), the AMP content accounts for 60% of the total volume of the absorbent, and the activator and solvent content account for 40% of the total volume of the absorbent. The volume ratio of the activator to the solvent is 1:4.6.

[0054] Example 4:

[0055] This embodiment discloses a novel CO2 absorbent, which includes 2-amino-2-methyl-1-propanol (AMP), an activator, and a solvent. The activator is pentamethyldiethylenetriamine (PMDETA), the solvent is 1,4-butanediol (BDO), the AMP content accounts for 60% of the total volume of the absorbent, and the activator and solvent content accounts for 40% of the total volume of the absorbent. The volume ratio of the activator to the solvent is 1:5.1.

[0056] The CO2 absorption effect of the novel CO2 absorbent of this invention is tested as follows:

[0057] (1) Absorption performance test of different CO2 absorbents in Examples 1-4 at 60°C:

[0058] Experimental Method: 50 mL of each of the CO2 absorbents from Examples 1-4 were added to separate bubbling absorption bottles and placed in a 60°C water bath. CO2 gas was introduced into the bubbling absorption bottles at a flow rate of 50 mL / min. A stopwatch was started, and the CO2 flow rate at the inlet and outlet of the bubbling absorption bottles was monitored using a soap film flow meter. When the CO2 flow rates at the inlet and outlet of the bubbling absorption bottles were equal, indicating that the CO2 absorbent solution had reached saturation, the experiment was considered complete. This experiment allows us to obtain the change in the CO2 absorption rate of different absorbents over time. The relationship between time and absorption rate was then integrated to obtain the curves showing the change in the CO2 absorption load of different absorbents over time, as shown below. Figure 1 As shown.

[0059] Depend on Figure 2 It can be seen that, in the CO2 absorption tests of different components of CO2 absorbents in Examples 1 to 4, the CO2 absorbent prepared in Example 1 has the largest absorption load and the fastest absorption reaction time; the CO2 absorbent prepared in Example 4 has the smallest absorption load; and the CO2 absorbent prepared in Example 3 has the slowest absorption reaction time.

[0060] (2) Desorption performance test of precipitates after CO2 absorption by different CO2 absorbents in Examples 1-4 at 120°C:

[0061] Experimental Method: 100 mg of the precipitate from each of the different CO2 absorbents in Examples 1-4 was taken and added to separate flasks. The flasks were heated using a microwave, and a stopwatch was started. The CO2 flow rate at the flask outlet was monitored using a soap film flow meter. The experiment was considered complete when no more CO2 was discharged from the flask outlet. This experiment allows us to determine the relationship between the CO2 content of the solid precipitate in Examples 1-4 and time. Figure 2 As shown; then, the CO2 content was compared with time to obtain the desorption rate curves of the solid precipitates in Examples 1-4, as shown. Figure 3 As shown.

[0062] Depend on Figure 3 It can be seen that the CO2 content in the solid precipitate produced by the CO2 absorbent prepared in Example 1 was the highest at 95%; the CO2 content in the solid precipitate produced by the CO2 absorbent prepared in Example 2 was the lowest at 88%; and the CO2 content in the solid precipitates produced by the different CO2 absorbents prepared in Examples 1-4 was all above 85%. Figure 3It can be seen that the desorption rate of the CO2 absorbent prepared in Example 1 is the fastest, reaching 81%; the desorption rate of the solid precipitate produced by the CO2 absorbent prepared in Example 3 is the slowest, reaching 76%; and the reaction rate of the solid precipitate produced by the CO2 absorbent prepared in Example 4 is the slowest, reaching the highest desorption rate only after 60 minutes of reaction.

[0063] In summary, based on the CO2 absorption experiments conducted by different CO2 absorbents in Examples 1-4, it can be seen that the solvent in the absorbent can affect CO2 absorption. Among them, the CO2 absorbent made from 2-amino-2-methyl-1-propanol (AMP), pentamethyldiethylenetriamine (PMDETA), and propanol has a relatively better effect; the CO2 absorbent using ethanol or 1,4-butanediol (BDO) as solvents has a poorer CO2 adsorption effect.

[0064] It should be noted that the different CO2 absorbents prepared in Examples 1 to 4 are only preferred embodiments of the CO2 absorbents of the present invention. The present invention is not limited to the above-mentioned CO2 absorbent formulation components, such as the combination of ethanol and propanol as solvent components of the absorbent, or the volume ratio of activator to solvent being 1:6, 1:7, etc., which are not limited here.

[0065] Example 5:

[0066] like Figure 4 As shown, the carbon dioxide capture system of the present invention includes an absorption tower 1, a solid-liquid separator 3, and a desorption tower 6. An inlet 11 is provided on one side of the lower part of the absorption tower 1, and an outlet 12 is provided at the top of the absorption tower 1. CO2-containing flue gas is introduced into the absorption tower 1 through the inlet 11, and purified flue gas is discharged through the outlet 12. A liquid inlet 13 is provided on one side of the upper part of the absorption tower 1, and a liquid outlet 14 is provided at the bottom of the absorption tower 1. Inside the absorption tower 1, CO2 flue gas enters through the inlet 11 and moves upwards along the absorption tower 1. The CO2 absorbent and circulating absorbent enter through the liquid inlet 13 of the absorption tower 1 and absorb the CO2 flue gas countercurrently. After absorbing CO2, the novel CO2 absorbent forms solid particles that precipitate at the bottom of the absorption tower 1 to form a slurry. The purified flue gas is discharged through the outlet 12.

[0067] A solid-liquid separator 3 is installed on one side of the absorption tower 1. The upper side of the solid-liquid separator 3 has a liquid inlet, which is connected to the discharge port 14 of the absorption tower 1 via a conveying pipe. A conveying pump 2 is connected to this conveying pipe, which transports the bottom liquid of the absorption tower 1 to the solid-liquid separator 3 for liquid-solid separation. The top of the solid-liquid separator 3 has a liquid discharge end 31, and the bottom of the solid-liquid separator 3 has a concentrated slurry discharge end 32. The conveying pump 2 draws the slurry containing solid particles and CO2 absorbent from the bottom of the absorption tower 1 and sends it into the solid-liquid separator 3 for liquid-solid separation, forming CO2 absorbent and a concentrated rich phase. The concentrated rich phase is transported to the desorption tower 6, while the CO2 absorbent is returned to the absorption tower 1 through the liquid discharge end 31 for circulating absorption and purification.

[0068] A rich phase inlet end 62 is provided on the upper side of the desorption tower 6. The rich phase inlet end 62 is connected to the concentrated slurry discharge end 32 through the concentrated slurry conveying pipeline 33. The concentrated slurry conveying pipeline 33 is connected to the heater 4 and the heat exchanger 5. The heater 4 can preheat the slurry rich in CO2 solid particles conveyed by the solid-liquid separator 3. The heat exchanger 5 is used to exchange heat between the regenerated absorbent lean liquor and the rich phase slurry generated by the desorption tower 6. The regenerated lean liquor after heat exchange will be returned to the absorption tower 1 through the return pipe 9 for recycling.

[0069] A reflux end 61 is provided at the bottom of the desorption tower 6. The reflux end 61 is connected to the liquid inlet 13 of the absorption tower through a reflux pipe 9. The reflux pipe 9 and the concentrated slurry conveying pipeline 33 are respectively connected to the inner and outer flow channels of the heat exchanger 5. The liquid discharge end 31 of the solid-liquid separator 3 is connected to the reflux pipe 9. The absorbent liquid separated by the solid-liquid separator 3 is recycled back into the absorption tower 1 through the reflux pipe 9 for CO2 absorption. A cooler 91 is connected to the reflux pipe 9 to cool the absorbent entering the absorption tower 1. A flash evaporator 7 and a compressor 8 are provided on one side of the desorption tower 6. The flash evaporator 7 is connected to the compressor 8 and provides heat to the desorption tower 6. The solid slurry in the desorption tower 6 is heated and decomposed by the flash evaporator 7 and the compressor 8 to obtain separated CO2.

[0070] This invention employs a novel CO2 absorbent capture system. CO2 is absorbed and solidified by the CO2 absorbent, then separated into solid and liquid phases by a solid-liquid separator 3. The concentrated slurry that absorbed CO2 is then thermally decomposed and regenerated by a desorption tower 6. This significantly reduces the regeneration volume of the CO2 absorbent, thereby lowering regeneration energy consumption. After desorption, the CO2-rich slurry can be converted into a liquid phase and mixed with the lean CO2 absorbent solution separated by the solid-liquid separator 3 before being recycled back into the absorption tower 1 for absorption and reuse.

[0071] Example 6:

[0072] Based on Example 5, such as Figure 5-6As shown, a heat recovery mechanism 10 is provided at the top of the exhaust end 63 of the desorption tower. The heat recovery mechanism 10 can recover the heat of the high-heat CO2 gas discharged from the desorption tower 6, avoid the waste of heat of the emitted CO2 gas, and improve the environmental protection production effect of the capture system.

[0073] The heat recovery mechanism 10 includes an exhaust pipe 102, a heat exchange pipe 103, and a heat insulation shell 101. The exhaust pipe 102 is fixedly connected to the exhaust end 63, and the outlet end of the exhaust pipe 102 is connected to a CO2 storage unit for utilizing and storing the CO2 discharged from the desorption tower 6 to reduce carbon emissions.

[0074] The heat exchange tube 103 is made of thermally conductive metal material and is connected to the exhaust pipe 102. The heat insulation shell 101 is fixedly fitted outside the heat exchange tube 103. The heat exchange fluid 104 is filled between the heat insulation shell 101 and the heat exchange tube 103. The heat exchange tube 103 can exchange heat with the heat exchange fluid 104 to prevent heat loss from CO2. The heat exchange fluid 104 can be water. The water that absorbs heat during heat exchange can be used for bathing or washing hands to improve the utilization efficiency of the capture system.

[0075] A liquid level sensor 123 and a temperature sensor 125 are provided on the inner wall of the heat insulation housing 101. The temperature sensor 125 is used to monitor the temperature of the heat exchange fluid 104. When the temperature of the heat exchange fluid 104 reaches a preset temperature, for example, when the temperature of the heat exchange fluid 104 reaches 50°C, it can be drained in time for subsequent use. The liquid level sensor 123 is used to monitor the liquid level of the heat exchange fluid 104 inside the heat insulation housing 101. Both the liquid level sensor 123 and the temperature sensor 125 can be implemented using existing technologies.

[0076] A filling pipe 126 and a drain pipe 127 are connected to the outer wall of the heat insulation shell 101. The filling pipe 126 is used to replenish the heat exchange fluid 104, and the drain pipe 127 is used to discharge the heat exchange fluid 104 after heat exchange for subsequent use. The filling pipe 126 is connected to the water supply end, and the drain pipe 127 is connected to the storage tank (not shown in the figure). Both the filling pipe 126 and the drain pipe 127 are equipped with control valves (not shown in the figure). When the heat exchange fluid 104 in the heat insulation shell 101 is discharged, the water supply end is used to replenish the heat exchange fluid 104 in the heat insulation shell 101, and the storage tank is used to store the heat exchange fluid 104 after heat exchange for subsequent use.

[0077] Specifically, when the temperature sensor 125 inside the insulation housing 101 detects that the temperature of the heat exchange fluid 104 reaches the preset temperature of 50°C, the control valve on the drain pipe 127 opens, and the heat exchange fluid 104 enters the storage tank through the drain pipe. When the liquid level sensor 123 inside the insulation housing 101 detects that the liquid level of the heat exchange fluid 104 is low, the control valve on the drain pipe is closed, and the control valve on the filling pipe 126 is opened. The water supply end replenishes the heat exchange fluid 104 into the insulation housing 101 through the filling pipe 126, so that the low-temperature heat exchange fluid 104 can be used for heat exchange again, and so on in a cycle.

[0078] Example 7:

[0079] Based on Example 6, such as Figure 6-7 As shown, a hollow heat exchange plate 105 is provided inside the heat exchange tube 103. The hollow heat exchange plate 105 can exchange heat with the passing high-temperature CO2, improving the heat exchange efficiency. Two connecting plates 106 are symmetrically connected to both ends of the hollow heat exchange plate 105. The connecting plates 106 are connected to the outer wall of the heat exchange tube 103 and immersed in the heat exchange liquid 104. The heat exchange heat of the hollow heat exchange plate 105 is transferred to the heat exchange liquid 104 through the connecting plates 106, causing the heat exchange liquid 104 to heat up. A rotating shaft 108 is provided inside the cavity of the hollow heat exchange plate 105, which is rotatably supported on the two connecting plates 106. Blades 109 are connected to the inner side wall of the hollow heat exchange plate 105, and a stirring plate 110 is connected to the outer end of the rotating shaft 108 inside the heat exchange liquid 104. Multiple sets of through holes 107 are respectively provided on the upper and lower surfaces of the hollow heat exchange plate 105. When high-temperature CO2 gas passes through the through-hole 107, it comes into contact with and is pushed by the blades 109 inside the heat exchange hollow plate 105, which in turn drives the rotating shaft 108 to rotate. The rotating shaft 108 drives the stirring blades 110 to rotate, which in turn stirs the heat exchange fluid 104, enabling the heat exchange fluid 104 to exchange heat uniformly and improving the CO2 conversion efficiency. Specifically, to ensure that the flowing CO2 can drive the rotating shaft 108 to rotate, the through-hole 107 and the blades 109 are correspondingly arranged.

[0080] like Figure 8As shown, a baffle 111 is provided inside the heat exchange tube 103 on the upper side of the heat exchange hollow plate 105. The baffle 111 is used to block the high-temperature CO2 airflow, thereby prolonging the heat exchange time of the high-temperature CO2 and improving the heat exchange effect. Multiple vent holes 112 are provided through the baffle 111, so that the CO2 after heat exchange can be discharged through the vent holes 112 and then discharged through the exhaust pipe 103. A sliding rod 113 is vertically slidably connected to the partition 111. A cover plate 114 is connected to the top of the sliding rod 113. The cover plate 114 is fastened to the partition 111 and can block the vent hole 112. A load plate 115 is connected to the bottom of the sliding rod 113. A load block 116 is connected to the lower end of the load plate 115. The load block 116 increases the counterweight of the sliding rod 113. When there is no CO2 in the heat exchange tube 103 or the CO2 gas flow rate is slow, the cover plate 114 covers the vent hole 112. The CO2 gas can stay in the heat exchange tube 103 for a longer time, so that the CO2 and the heat exchange liquid 104 can exchange heat fully and avoid the loss of CO2 heat.

[0081] like Figure 6 and Figure 9 As shown, two hollow tubes 117 are horizontally slidably connected to the two side walls of the heat exchange tube 103. The outer end of the hollow tube 117 can slide into the heat exchange liquid 104. A limiting ring 122 is connected to the side wall of the hollow tube 117 located in the heat exchange liquid 104. The limiting ring 122 is used to limit the sliding distance of the hollow tube 117 to prevent the hollow tube 117 from sliding completely into the heat exchange tube 103. A linkage ring 118 is provided below the load block 116. The linkage ring 118 is fixedly connected to the inner wall of the heat exchange tube 103 by a fixing rod. A cavity 119 is provided inside the linkage ring 118, and a linkage rope 121 is horizontally arranged through the cavity 119. The two ends of the linkage rope 121 are fixedly connected to one end of the inner side of the hollow tube 117. A pull rope 120 is connected to the load block 116. The lower end of the pull rope 120 is connected to the center of the linkage rope 121. In order to avoid wear of the linkage rope 121, a pair of fixed pulleys (not shown in the figure) are provided inside the linkage ring 118. The linkage rope 121 is connected to the fixed pulleys, which can be used to extend the service life of the linkage rope 121.

[0082] When the CO2 gas flow rate inside the heat exchange tube 103 is large, its gas pressure is large, which causes the lifting cover plate 114 to move upward and drive the load block 116 to rise. The load block 116 pulls the linkage rope 121 through the pull rope 120, which drives the hollow tube 117 to move inward and towards each other, increasing the contact area between the hollow tube 117 and the high-temperature CO2 gas and improving the heat exchange efficiency of the high-temperature CO2.

[0083] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A carbon dioxide absorbent, characterized in that, The absorbent comprises 2-amino-2-methyl-1-propanol AMP, an activator, and a solvent; wherein the activator is pentamethyldiethylenetriamine PMDETA; and the solvent is one or a combination of ethanol, propanol, polyethylene glycol PEG200, and 1,4-butanediol BDO. The AMP content accounts for 60% of the total volume of the absorbent, and the activator and solvent content accounts for 40% of the total volume of the absorbent. The volume ratio of the activator to the solvent is 1:(2~7).

2. The carbon dioxide absorbent according to claim 1, characterized in that, The activator is PMDETA, the solvent is propanol, and the volume ratio of PMDETA to propanol is 1:

2.

3. A carbon dioxide capture system, employing the carbon dioxide absorbent as described in any one of claims 1-2, characterized in that, The capture system includes: An absorption tower (1) is provided with an air inlet (11), an air outlet (12), a liquid inlet (13) and a liquid outlet (14). A solid-liquid separator (3) is provided with a liquid discharge end (31) and a slurry discharge end (32) on the solid-liquid separator (3). The liquid inlet of the solid-liquid separator (3) is connected to the liquid outlet (14) of the absorption tower (1) through a conveying pipe, and a conveying pump (2) is connected to the conveying pipe. The desorption tower (6) is provided with a reflux end (61), a rich phase inlet end (62) and an exhaust end (63); the rich phase inlet end (62) is connected to the slurry discharge end (32) through a conveying pipeline, and the conveying pipeline is connected to the heater (4) and the heat exchanger (5); the reflux end (61) is connected to the liquid inlet (13) of the absorption tower through a reflux pipe (9), the reflux pipe (9) is connected to the heat exchanger (5) and the liquid discharge end (31) of the solid-liquid separator, and a cooler (91) is connected to the reflux pipe (9); The exhaust end (63) of the desorption tower is equipped with a heat recovery mechanism (10) at its top, and the heat recovery mechanism (10) includes: An exhaust pipe (102) is fixedly connected to the exhaust end (63); A heat exchange tube (103) is made of a thermally conductive metal material and is connected to the exhaust pipe (102); A heat insulation shell (101) is fixedly fitted outside the heat exchange tube (103), and a heat exchange liquid (104) is filled between the heat insulation shell (101) and the heat exchange tube (103); a liquid level sensor (123) and a temperature sensor (125) are provided on the inner wall of the heat insulation shell (101), and a filling pipe (126) and a drain pipe (127) are connected to the outer wall of the heat insulation shell (101). The filling pipe (126) is connected to the water supply end, and the drain pipe (127) is connected to the liquid storage tank. Both the filling pipe (126) and the drain pipe (127) are equipped with control valves. The heat exchange tube (103) is provided with a heat exchange hollow plate (105). Two connecting plates (106) are symmetrically connected to both ends of the heat exchange hollow plate (105). The connecting plates (106) are connected to the outer wall of the heat exchange tube (103) and immersed in the heat exchange liquid (104). A rotating shaft (108) is provided in the cavity of the heat exchange hollow plate (105) and is rotatably supported on the two connecting plates (106). Blades (109) are connected to the side wall of the rotating shaft (108) located inside the heat exchange hollow plate (105). A stirring blade (110) is connected to the outer end of the rotating shaft (108) located inside the heat exchange liquid (104). Multiple sets of through holes (107) are respectively provided on the upper and lower surfaces of the heat exchange hollow plate (105).

4. The carbon dioxide capture system according to claim 3, characterized in that, The desorption tower (6) is equipped with a flash evaporator (7) and a compressor (8). The flash evaporator (7) is connected to the compressor (8) and provides heat to the desorption tower (6).

5. The carbon dioxide capture system according to claim 3, characterized in that, A partition (111) is provided inside the heat exchange tube (103) on the upper side of the heat exchange hollow plate (105). A plurality of vent holes (112) are provided through the partition (111). A slide rod (113) is vertically slidably connected to the partition (111). A cover plate (114) is connected to the top of the slide rod (113). The cover plate (114) is fastened to the partition (111) and can block the vent holes (112). A load plate (115) is connected to the bottom of the slide rod (113). A load block (116) is connected to the lower end of the load plate (115).

6. The carbon dioxide capture system according to claim 5, characterized in that, Two hollow tubes (117) are horizontally slidably connected to the two side walls of the heat exchange tube (103). The outer end of the hollow tube (117) can slide into the heat exchange liquid (104), and a limit ring (122) is connected to the side wall of the hollow tube (117) at one end of the heat exchange liquid (104). A linkage ring (118) is provided below the load-bearing block (116). The linkage ring (118) is fixedly connected to the inner wall of the heat exchange tube (103) by a fixing rod. A cavity (119) is provided inside the linkage ring (118), and a linkage rope (121) is horizontally arranged through the cavity (119) of the linkage ring (118). The two ends of the linkage rope (121) are fixedly connected to one end of the inner side of the hollow tube (117). A pull rope (120) is connected to the weight block (116), and the lower end of the pull rope (120) is connected to the center of the linkage rope (121).

Images