System and method for enhancing carbon dioxide amine method absorption by utilizing micro-nano bubbles

Abstract

The invention discloses a system and a method for enhancing carbon dioxide amine method absorption by utilizing micro-nano bubbles, and relates to the technical field of carbon dioxide absorption. According to the invention, the structure that the raw material gas, the micro-nano bubble generation device, the absorbent solution tank, the ultrasonic generator, the small desorption device, the dryer and the CO2 analyzer are matched with one another is arranged, so that a micro-nano bubble technology and an absorbent with a slow absorption rate can be coupled, and a novel CO2 trapping process method is formed; the physical characteristics of large specific surface area and high mass transfer efficiency of micro-nano bubbles are utilized, and two gas generation modules with different bubble sizes are arranged, so that the absorption efficiency of the CO2 absorbent with low desorption energy consumption and poor absorption effect is improved.

Description

Technical Field

[0001] The present application relates to the technical field of carbon dioxide absorption, and in particular to a system and method for enhancing carbon dioxide amine absorption using micro-nano bubbles. Background Art

[0002] Currently, the alcohol amine solution absorption method (amine process) is the predominantly used CO2 capture method, offering advantages such as high adsorption capacity and rapid reaction rates. The basic principle of amine-based CO2 capture technology is to absorb the CO2 in the mixed gas through a chemical reaction between the amine solution and the CO2 in the mixed gas, forming a chemical bond. The CO2 is then released through thermal decomposition and regeneration.

[0003] The traditional absorbent, monoethanolamine (MEA), has a high absorption capacity and good selectivity, but its regeneration energy consumption is as high as 4.0 GJ / tCO2. Excessive regeneration energy consumption will significantly increase the operating costs of CO2 capture technology, so using absorbents with low regeneration energy consumption is a key factor in reducing the cost of carbon dioxide capture. Studies have shown that MDEA has low regeneration energy consumption after absorbing CO2, only 1 / 2 of that of MEA solution. However, the reaction rate during the absorption of CO2 by a pure MDEA aqueous solution is slow, resulting in low absorption efficiency. In addition to MDEA, other absorbents with low regeneration energy consumption generally suffer from poor absorption performance. Increasing the amine content to increase the absorption load will lead to the problem of excessively high viscosity of the amine rich solution. Therefore, how to improve the CO2 absorption efficiency of this type of absorbent is currently the main research and development direction. Summary of the Invention

[0004] The purpose of this application is to provide a system and method for enhancing carbon dioxide amine absorption using micro-nano bubbles to solve the problem of low absorption efficiency caused by the slow reaction rate of existing MDEA in absorbing CO2.

[0005] On the one hand, the present application provides a system for enhancing carbon dioxide amine absorption by using micro-nano bubbles, which adopts the following technical solutions: A carbon dioxide amine absorption system using micro-nano bubbles to enhance the carbon dioxide absorption, comprising raw gas, a micro-nano bubble generating device, an absorbent solution tank, an ultrasonic generator, a small desorption device, a dryer, and a CO2 analyzer; The raw gas, the micro-nano bubble generating device, the absorbent solution tank, the ultrasonic generator, the small desorption device, the dryer, and the CO2 analyzer are connected in sequence; A liquid outlet pump is provided between the absorbent solution tank and the ultrasonic generator, and a rich liquid pump is provided between the ultrasonic generator and the small desorption device.

[0006] Furthermore, the micro-nano bubble device comprises a bubble generating module A and a bubble generating module B. The bubble generating module A generates bubbles with a size of 50-80 microns, and the bubble generating module B generates bubbles with a size of 100-500 nanometers.

[0007] Furthermore, the top of one side of the absorbent solution tank is respectively connected to the bubble generating module A and the bubble generating module B, and the bubble generating module A and the bubble generating module B are simultaneously connected to the raw gas. A liquid inlet pump A is also provided between the bubble generating module A and the absorbent solution tank, and a liquid inlet pump B is also provided between the bubble generating module B and the absorbent solution tank.

[0008] Furthermore, the ultrasonic generator is provided with a liquid inlet, a liquid outlet, and an exhaust port. The top of the other side of the absorbent solution tank is connected to the liquid inlet of the ultrasonic generator, and the liquid outlet of the ultrasonic generator is connected to the top of the small desorption device.

[0009] On the other hand, the present application also provides a method for enhancing carbon dioxide amine absorption using micro-nano bubbles, which adopts the following technical solution: A method for enhancing carbon dioxide amine absorption using micro-nano bubbles comprises the following steps: S1, prepare MDEA into a 20% concentration aqueous solution as an absorbent; S2. Place the absorbent in the absorbent solution tank, pump it to the micro-nano bubble generating device through the liquid inlet pump A, and enter the bubble generating module A; S3, at the same time, a certain amount of CO2 / N2 mixed gas is introduced into the bubble generating module A; After the S4 and CO2 / N2 mixed gas passes through the bubble generation module A, micron bubbles with a diameter of 50-80μm are formed. The micron bubbles react rapidly with the absorption liquid. The absorption liquid that has absorbed the gas returns to the liquid inlet through the liquid outlet of the bubble generation module A and circulates for a period of time. S5. After the absorbent and gas circulate in the bubble generating module A for a period of time, they enter the bubble generating module B through the liquid inlet pump B. The CO2 / N2 mixed gas forms nanobubbles with a diameter of 100-500nm after passing through the bubble generating module B, further increasing the reaction rate of the absorbent and the gas. The absorption liquid that has absorbed the gas returns to the liquid inlet through the liquid outlet of the bubble generating module B and circulates for a period of time. S6, the absorption liquid that absorbs the gas to saturation enters the ultrasonic generating device through the outlet of the bubble generating module B and the liquid outlet pump. This step is to eliminate a small amount of N2 dissolved in the absorption liquid; S7. The absorption liquid enters the small desorption device through the rich liquid pump to be heated and desorbed to remove CO2. The desorbed gas is dried in the dryer and then enters the CO2 analyzer to detect the CO2 purity.

[0010] Furthermore, the liquid inlet flow rate of the absorbent is 2 L / min, and the gas inlet flow rate of the CO2 / N2 mixed gas is 1 L / min.

[0011] Furthermore, the operating frequency of the ultrasonic generator is 20kHz-50kHz.

[0012] Furthermore, the operating temperature of the small desorption device is 100-105°C.

[0013] Compared with the prior art, the present invention has the following advantages: The purpose of this application is to provide a method for improving the CO₂ absorption capacity of MDEA absorbent using micro-nano bubble technology, thereby reducing the concentration of MDEA absorbent used and further reducing carbon capture costs. Furthermore, the carbon capture system provided by this invention has a small footprint, saving space, and can be constructed as a skid-mounted system with multiple modules, making it more suitable for industrial scenarios with low CO₂ emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of an embodiment of the present application using micro-nano bubbles to enhance the carbon dioxide amine absorption system.

[0015] Description of reference numerals: 1. Raw gas; 2. Micro-nano bubble generator; 3. Bubble generator module A; 4. Bubble generator module B; 5. Liquid inlet pump A; 6. Liquid inlet pump B; 7. Absorbent solution tank; 8. Liquid outlet pump; 9. Ultrasonic generator; 10. Rich liquid pump; 11. Small desorption device; 12. Dryer; 13. CO2 analyzer. DETAILED DESCRIPTION

[0016] The following is combined with Figure 1 This application is described in further detail.

[0017] On the one hand, the present application provides a carbon dioxide amine absorption system using micro-nano bubbles to enhance the carbon dioxide amine absorption system. Figure 1 In this embodiment, the system includes a raw gas 1, a micro-nano bubble generator 2, an absorbent solution tank 7, an ultrasonic generator 9, a small desorption device 11, a dryer 12, and a CO2 analyzer 13. The raw gas 1, the micro-nano bubble generator 2, the absorbent solution tank 7, the ultrasonic generator 9, the small desorption device 11, the dryer 12, and the CO2 analyzer 13 are connected to each other from left to right via pipes.

[0018] At the same time, the raw gas 1 stores a CO2 / N2 mixed gas so that the CO2 / N2 mixed gas can be transported to the micro-nano bubble generating device 2; and the micro-nano bubble generating device 2 includes a bubble generating module A3 and a bubble generating module B4; the bubble generating module A3 and the bubble generating module B4 are simultaneously interconnected with the raw gas 1 so that the CO2 / N2 mixed gas can be transported to the bubble generating module A3 and the bubble generating module B4 respectively, so that the bubble size generated by the bubble generating module A3 is 50-80 microns, and the bubble size generated by the bubble generating module B4 is 100-500 nanometers.

[0019] In addition, refer to Figure 1 In this embodiment, the absorbent solution tank 7 stores absorbent, and the top end of the absorbent solution tank 7 is interconnected with the bubble generating module A3 and the bubble generating module B4. Specifically, the liquid inlet of the bubble generating module A3 is interconnected with the top end of the absorbent solution tank 7 via a first liquid inlet pipe. A liquid inlet pump A5 is also provided between the bubble generating module A3 and the absorbent solution tank 7, and is mounted on the first liquid inlet pipe. By activating the liquid inlet pump A5, the absorbent liquid is pumped into the bubble generating module A3.

[0020] More specifically, the liquid outlet of the bubble generating module A3 is connected to the liquid inlet end of the first liquid inlet pipe through the first liquid outlet pipe, so that the absorption liquid in the bubble generating module A3 returns to the first liquid inlet pipe through the first liquid outlet pipe, and then under the action of the liquid inlet pump A5, the absorption liquid achieves the effect of circulating absorption gas.

[0021] Correspondingly, the liquid inlet of the bubble generating module B4 is connected to the top of one side of the absorbent solution tank 7 through a second liquid inlet pipe, and a liquid inlet pump B6 is also provided between the bubble generating module B4 and the absorbent solution tank 7, and the liquid inlet pump B6 is installed on the second liquid inlet pipe; by starting the liquid inlet pump B6, the absorption liquid can be pumped into the bubble generating module B4.

[0022] More specifically, the liquid outlet of the bubble generating module B4 is connected to the liquid inlet end of the second liquid inlet pipe through the second liquid outlet pipe, so that the absorption liquid in the bubble generating module B4 returns to the second liquid inlet pipe through the second liquid outlet pipe, and then under the action of the liquid inlet pump B6, the absorption liquid achieves the effect of circulating absorption gas.

[0023] In this way, by circulating the absorbent in the bubble generating module A3 and the bubble generating module B4, the absorbent can more fully and effectively absorb the gas, so that the absorbent absorbs the gas to saturation, thereby improving the accuracy of the experiment.

[0024] In addition, in this embodiment, the ultrasonic generator 9 is provided with a liquid inlet, a liquid outlet, and an exhaust port. The other top end of the absorbent solution tank 7 is interconnected with the liquid inlet of the ultrasonic generator 9. A liquid outlet pump 8 is also provided between the other top end of the absorbent solution tank 7 and the ultrasonic generator 9. The liquid outlet pump 8 is installed on the pipeline between the absorbent solution tank 7 and the ultrasonic generator 9. When the liquid outlet pump 8 is activated, it can transport the absorption liquid saturated with the absorbed gas to the ultrasonic generator device, so that the ultrasonic generator 9 can perform ultrasonic treatment on the absorption liquid to eliminate the small amount of N2 dissolved in the absorption liquid.

[0025] At the same time, the liquid outlet of the ultrasonic generator 9 is connected to the top of the small desorption device 11, and a rich liquid pump 10 is also provided between the top of the ultrasonic generator 9 and the top of one side of the small desorption device 11. Through the setting of the rich liquid pump 10, the ultrasonically treated absorption liquid can be transported into the small desorption device 11, so that the small desorption device 11 heats the absorption liquid to desorb CO2, and then the heated and desorbed gas is discharged from the outlet of the small desorption device 11 into the dryer 12 for drying treatment, and then enters the CO2 analyzer 13 for CO2 purity detection.

[0026] On the other hand, the present invention discloses a method for enhancing carbon dioxide amine absorption using micro-nano bubbles, comprising the following steps: S1. Prepare MDEA into a 20% aqueous solution as an absorbent.

[0027] S2. Place the absorbent in the absorbent solution tank 7, pump it to the micro-nano bubble generating device 2 through the liquid inlet pump A5, and enter the bubble generating module A3.

[0028] S3. At the same time, a certain amount of CO2 / N2 mixed gas is introduced into the bubble generating module A3.

[0029] After the S4 and CO2 / N2 mixed gas passes through the bubble generation module A3, it forms micron bubbles with a diameter of 50-80μm. The micron bubbles react rapidly with the absorption liquid. The absorption liquid that has absorbed the gas returns to the liquid inlet through the liquid outlet of the bubble generation module A3 and circulates for a period of time. The specific chemical reaction formula is as follows: .

[0030] S5. After the absorbent and gas circulate in the bubble generating module A3 for a period of time, they enter the bubble generating module B4 through the liquid inlet pump B6. The CO2 / N2 mixed gas forms nanobubbles with a diameter of 100-500nm after passing through the bubble generating module B4, further increasing the reaction rate of the absorbent and the gas. The absorption liquid that absorbs the gas returns to the liquid inlet through the liquid outlet of the bubble generating module B4 and circulates for a period of time.

[0031] S6. The absorption liquid that has absorbed the gas to saturation enters the ultrasonic generating device through the outlet of the bubble generating module B4 and the liquid outlet pump 8. This step is to eliminate a small amount of N2 dissolved in the absorption liquid.

[0032] S7, the absorption liquid enters the small desorption device 11 through the rich liquid pump 10 to be heated and desorbed to remove CO2. The desorbed gas is dried by the dryer 12 and then enters the CO2 analyzer 13 to detect the CO2 purity.

[0033] More specifically, the following is a comparison of different absorbent masses, gas flow rates, and ventilation times based on the above-mentioned experimental test method of using micro-nano bubble technology to promote MDEA absorption of CO2: Example 1: A 20% MDEA aqueous solution was placed in absorbent solution tank 7 and pumped to bubble generation module A3 in the nanobubble generator via inlet pump A5 at a flow rate of 2 L / min. A CO2 / N2 mixture (15% CO2 concentration) was introduced into bubble generation module A3 at a flow rate of 1 L / min, generating microbubbles with a diameter of 50-80 μm. The absorbent and microbubbles rapidly reacted in bubble generation module A3. The CO2-absorbed absorbent returned to the module through the outlet, where it continued to react with the microbubbles.

[0034] After circulating this step for 20 minutes, the gas and the absorption-rich liquid enter the bubble generation module B4, where the gas generates nanobubbles with a diameter of 100-500nm, and the absorption-rich liquid further reacts with the nanobubbles. After the absorption liquid and nanobubbles circulate in the bubble generation module B4 for 10 minutes, the absorption-rich liquid enters the ultrasonic generator 9 through the liquid outlet pump 8. The operating frequency of the ultrasonic generator 9 is set to 30kHz and the time is 10 minutes. After ultrasonication, the absorption-rich liquid enters the top of the small desorption device 11 using the rich liquid pump 10. The liquid inlet flow rate is set to 0.5L / min and the heating temperature is 100°C. The outlet gas of the small desorption device 11 is dried by the dryer 12 and then enters the CO2 analyzer 13 to detect the CO2 purity.

[0035] Comparative example: For comparison, the laboratory uses a small absorption-desorption linkage device to conduct CO2 capture tests, and parameters such as liquid-gas ratio and desorption temperature remain consistent.

[0036] Example 1: A 20% MDEA aqueous solution was placed in absorbent solution tank 7 and pumped to bubble generation module A3 in the nanobubble generator via inlet pump A5 at a flow rate of 2 L / min. A CO2 / N2 mixture (15% CO2 concentration) was introduced into bubble generation module A3 at a flow rate of 1.5 L / min, generating microbubbles with a diameter of 50-80 μm. The absorbent and microbubbles rapidly reacted in bubble generation module A3. The CO2-absorbed absorbent returned to the module through the outlet, where it continued to react with the microbubbles.

[0037] After circulating this step for 20 minutes, the gas and the absorption-rich liquid enter the bubble generation module B4, where the gas generates nanobubbles with a diameter of 100-500nm, and the absorption-rich liquid further reacts with the nanobubbles. After the absorption liquid and nanobubbles circulate in the bubble generation module B4 for 10 minutes, the absorption-rich liquid enters the ultrasonic generator 9 through the liquid outlet pump 8. The operating frequency of the ultrasonic generator 9 is set to 30kHz and the time is 10 minutes. After ultrasonication, the absorption-rich liquid enters the top of the small desorption device 11 using the rich liquid pump 10. The liquid inlet flow rate is set to 0.5L / min and the heating temperature is 100°C. The outlet gas of the small desorption device 11 is dried by the dryer 12 and then enters the CO2 analyzer 13 to detect the CO2 purity.

[0038] Example 2: A 20% MDEA aqueous solution was placed in absorbent solution tank 7 and pumped via inlet pump A5 to the bubble generation module A3 of the nanobubble generator at a flow rate of 2.5 L / min. A CO2 / N2 mixture (15% CO2 concentration) was introduced into the bubble generation module A3 at a flow rate of 1.5 L / min, generating microbubbles with a diameter of 50-80 μm. The absorbent and the microbubbles rapidly reacted in the bubble generation module A3. The absorbent, having absorbed the CO2, then returned to the module through the outlet, where it continued to react with the microbubbles.

[0039] After circulating this step for 20 minutes, the gas and the absorption-rich liquid enter the bubble generation module B4, where the gas generates nanobubbles with a diameter of 100-500nm, and the absorption-rich liquid further reacts with the nanobubbles. After the absorption liquid and nanobubbles circulate in the bubble generation module B4 for 10 minutes, the absorption-rich liquid enters the ultrasonic generator 9 through the liquid outlet pump 8. The operating frequency of the ultrasonic generator 9 is set to 40kHz and the time is 10 minutes. After ultrasonication, the absorption-rich liquid enters the top of the small desorption device 11 using the rich liquid pump 10. The liquid inlet flow rate is set to 0.5L / min and the heating temperature is 100°C. The outlet gas of the small desorption device 11 is dried by the dryer 12 and then enters the CO2 analyzer 13 to detect the CO2 purity.

[0040] The following table shows the implementation effects of the embodiments and comparative examples: It can be concluded from the above table that the absorption capacity of low-concentration MDEA for CO2 can be effectively improved by using micro-nano bubble technology.

[0041] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A carbon dioxide amine absorption system using micro-nano bubbles, characterized in that: It includes raw gas (1), a micro-nano bubble generating device (2), an absorbent solution tank (7), an ultrasonic generator (9), a small desorption device (11), a dryer (12), and a CO2 analyzer (13); The raw gas (1), the micro-nano bubble generating device (2), the absorbent solution tank (7), the ultrasonic generator (9), the small desorption device (11), the dryer (12), and the CO2 analyzer (13) are connected in sequence; A liquid outlet pump (8) is provided between the absorbent solution tank (7) and the ultrasonic generator (9), and a rich liquid pump (10) is provided between the ultrasonic generator (9) and the small desorption device (11).

2. The carbon dioxide amine absorption system using micro-nano bubbles as claimed in claim 1, characterized in that: The micro-nano bubble device (2) comprises a bubble generating module A (3) and a bubble generating module B (4). The bubble generating module A (3) generates bubbles with a size of 50-80 micrometers, and the bubble generating module B (4) generates bubbles with a size of 100-500 nanometers.

3. The carbon dioxide amine absorption system using micro-nano bubbles as claimed in claim 2, characterized in that: The top end of one side of the absorbent solution tank (7) is connected to the bubble generating module A (3) and the bubble generating module B (4), respectively. The bubble generating module A (3) and the bubble generating module B (4) are simultaneously connected to the raw gas (1). A liquid inlet pump A (5) is further provided between the bubble generating module A (3) and the absorbent solution tank (7), and a liquid inlet pump B (6) is further provided between the bubble generating module B (4) and the absorbent solution tank (7).

4. The carbon dioxide amine absorption system using micro-nano bubbles as claimed in claim 1, characterized in that: The ultrasonic generator (9) is provided with a liquid inlet, a liquid outlet, and an exhaust port. The top end of the other side of the absorbent solution tank (7) is connected to the liquid inlet of the ultrasonic generator (9), and the liquid outlet of the ultrasonic generator (9) is connected to the top end of the small desorption device (11).

5. A method for enhancing carbon dioxide amine absorption using micro-nano bubbles, according to any one of claims 1 to 4, wherein the system for enhancing carbon dioxide amine absorption using micro-nano bubbles is characterized in that: The following steps are involved: S1, prepare MDEA into a 20% concentration aqueous solution as an absorbent; S2, placing the absorbent in the absorbent solution tank (7), pumping it to the micro-nano bubble generating device (2) through the liquid inlet pump A (5), and then entering the bubble generating module A (3); S3, at the same time, a certain amount of CO2 / N2 mixed gas is introduced into the bubble generating module A (3); After the S4 and CO2 / N2 mixed gas passes through the bubble generating module A (3), micron bubbles with a diameter of 50-80 μm are formed. The micron bubbles react chemically with the absorption liquid rapidly. The absorption liquid that has absorbed the gas returns to the liquid inlet through the liquid outlet of the bubble generating module A (3) and circulates for a period of time. S5. After the absorbent and gas circulate in the bubble generating module A (3) for a period of time, they enter the bubble generating module B (4) through the liquid inlet pump B (6). The CO2 / N2 mixed gas forms nanobubbles with a diameter of 100-500nm after passing through the bubble generating module B (4), further increasing the reaction rate of the absorbent and the gas. The absorption liquid that has absorbed the gas returns to the liquid inlet through the liquid outlet of the bubble generating module B (4) and circulates for a period of time. S6, the absorption liquid that has absorbed the gas to saturation enters the ultrasonic generating device (9) through the outlet of the bubble generating module B (4) and the liquid outlet pump (8). This step is to eliminate a small amount of N2 dissolved in the absorption liquid; S7. The absorption liquid enters the small desorption device (11) through the rich liquid pump (10) to be heated to desorb CO2. The desorbed gas is dried by the dryer (12) and then enters the CO2 analyzer to detect the CO2 purity.

6. The method for enhancing carbon dioxide amine absorption by using micro-nano bubbles according to claim 5, characterized in that: The absorbent liquid inlet flow rate is 2 L / min, and the CO2 / N2 mixed gas inlet flow rate is 1 L / min.

7. The method for enhancing carbon dioxide amine absorption by using micro-nano bubbles according to claim 5, characterized in that: The operating frequency of the ultrasonic generator (9) is 20kHz-50kHz.

8. The method for enhancing carbon dioxide amine absorption using micro-nano bubbles according to claim 5, characterized in that: The operating temperature of the small desorption device (11) is 100-105°C.

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