A process for carbon dioxide capture using ammonia water for decarbonization

Abstract

This invention belongs to the field of carbon dioxide capture technology, specifically relating to a process for capturing carbon dioxide using ammonia water for decarbonization. It employs a two-stage absorption process: primary ammonia water absorption and secondary composite ammonia water absorption, enabling the capture of a large amount of carbon dioxide in a single stage. Subsequently, the ammonia-containing desorbed gas generated from the depressurized desorption of the primary ammonia-rich solution is directly used in the electrolytic desorption regeneration process of the secondary composite ammonia-rich solution. On one hand, the composite ammonia water absorbs the ammonia in the desorbed gas, achieving in-situ ammonia recovery without the need for an additional ammonia recovery device, thus avoiding secondary pollution. On the other hand, electrolysis enhances the desorption of CO2 in the composite ammonia-rich solution and promotes the adsorption of ammonia by the polymer liquid, achieving efficient regeneration of the composite ammonia water. The carbon dioxide obtained by this invention has high purity, effectively preventing ammonia leakage, and the absorbent can be recycled. This solves the problems of ammonia escape, low product purity, and the need for additional ammonia recovery processes in existing carbon dioxide capture technologies.

Description

Technical Field

[0001] This invention belongs to the field of carbon dioxide capture technology, specifically relating to a process for capturing carbon dioxide using ammonia water for decarbonization. Background Technology

[0002] Carbon dioxide emissions are a global environmental pollution problem that requires joint efforts to address, bringing a series of impacts such as increasingly severe global warming, more pronounced extreme weather events, the easy absorption of carbon dioxide in oceans to form carbonic acid, and the impact on biodiversity. Carbon dioxide emissions mainly come from industries and energy sectors, with coal, oil, and natural gas being the main fossil fuels. More than 50% of carbon dioxide emissions originate from coal-fired power plants. However, carbon dioxide is also an abundant resource. Capture, utilization, and storage of carbon dioxide are considered the most economical and feasible methods to reduce greenhouse gas emissions and mitigate global warming. Therefore, directly separating carbon dioxide from flue gas before it is emitted can greatly reduce carbon dioxide pollution and yield new chemical products or allow for reuse.

[0003] Currently, the most widely used carbon dioxide capture technology is chemical absorption, which has advantages such as good absorption efficiency and high absorption stability. Chemical absorption methods include amine capture, ammonia capture, and hot potassium alkali capture. Among them, ammonia capture has the lowest energy consumption, strong carbon dioxide absorption efficiency, and does not have problems such as equipment corrosion and absorbent degradation. Compared with alcohol amine decarbonization technology, ammonia capture technology has the advantages of effectiveness and directness, and can decarbonize efficiently and quickly. However, the current ammonia decarbonization process requires a high concentration of ammonia. Low concentrations of ammonia have low capture efficiency and are not easy to regenerate. High concentrations of ammonia can lead to ammonia escape, causing reagent loss and secondary pollution.

[0004] Patent CN104107629B discloses a flue gas carbon dioxide capture system and method. To capture carbon dioxide using ammonia water, it is necessary to detect and recover ammonia in the flue gas and heat the carbon capture rich liquid to recover the absorbent. Although this can solve the problem of volatilization loss of carbon dioxide captured by ammonia water to some extent, it adds an extra ammonia recovery process, and the heat recovery absorbent method may still cause secondary volatilization of ammonia.

[0005] Patent CN101318651B discloses a device and method for absorbing and recovering carbon dioxide from flue gas using ammonia as an absorbent. The method involves absorbing carbon dioxide at high temperature and then cooling it for recovery, resulting in carbon dioxide with low purity.

[0006] Patent CN104707451B discloses a method for carbon capture and synthesis of chemical products from ammonia-based flue gas. It also involves additional processes for ammonia recovery, and the products produced are diverse and require secondary separation before they can be utilized. Summary of the Invention

[0007] To address the aforementioned problems, the present invention aims to provide a process for carbon dioxide capture using ammonia water decarbonization, thereby solving the problems of ammonia escape requiring additional equipment for recovery, low purity of CO2 products, and low regeneration efficiency of absorbent in the prior art.

[0008] The technical content of this invention is as follows: This invention provides a process for carbon dioxide capture using ammonia water for decarbonization, comprising the following steps: Step 1: Treat the carbon-containing waste gas with electrostatic pressure for 8-14 minutes; The electrostatic pressurization has an electrostatic strength of 10-20 kV / m and a pressure of 0.03-0.04 MPa. On the one hand, the electrostatic field ionizes the gas, causing fine particulate matter in the waste gas to be charged and adsorbed and removed, thus playing a dust removal role and increasing the relative concentration of CO2 in the flue gas. On the other hand, under the condition of slight positive pressure, the waste gas enters the absorption tower with a stable flow rate and kinetic energy, which enhances the turbulent contact between the gas and liquid phases, which is beneficial to the subsequent mass transfer process with the ammonia absorbent, thereby improving the absorption reaction rate and absorption capacity. Step 2: The treated waste gas is subjected to primary absorption and secondary absorption in sequence; The first-stage absorption is as follows: the waste gas is passed from bottom to top through the ammonia water absorption tower and reacted countercurrently with the ammonia water treated by microwave radiation to absorb most of the CO2 in the waste gas, resulting in ammonia water rich liquid. The tail gas after absorption enters the second-stage absorption. The ammonia water is ammonia water with a mass concentration of 20-40% after being treated with microwave radiation; The microwave radiation treatment is as follows: ammonia water is heated by microwave irradiation at a power of 300-500W for 60-90s; microwave radiation (2450 MHz) can enhance the coordination ability of the lone pair electrons of nitrogen atoms, thereby enhancing the bonding reaction between ammonia water and carbon dioxide through nitrogen and oxygen atoms, and improving the absorption reaction activity of ammonia water. The secondary absorption is as follows: the exhaust gas after the primary absorption is passed from top to bottom through the composite ammonia water absorption tower, and reacts with the composite ammonia water in a countercurrent manner to deeply capture the residual CO2 in the exhaust gas and intercept any possible ammonia gas, so as to obtain a rich solution of composite ammonia water, and the purified exhaust gas is then discharged. The composite ammonia solution is made by adding 7-10 wt% polymeric liquid to an ammonia solution with a mass concentration of 10-15%. The polymer liquid is prepared from dimethyl diallyl ammonium chloride, cerium nitrate hexahydrate, and plasma-activated ionic liquid in a mass ratio of (11-15):(3-5):(31-35). The preparation method is as follows: dimethyl diallyl ammonium chloride, cerium nitrate hexahydrate, and plasma-activated ionic liquid are mixed in the specified ratio and polymerized under vacuum conditions at a temperature of 60-70℃ for 2-3 hours, resulting in a nucleophilic substitution reaction to form a polymer with a porous network structure. The plasma-modified ionic liquid is prepared by placing 1-propyl-1-methylpiperidine phosphate dihydrogen salt in a plasma treatment device and treating it for 10-20 minutes under the conditions of a treatment voltage of 50-100kV, a frequency of 20-30Hz, and a power of 35-40kW. This treatment can generate high-density free radicals on the surface and inside of the ionic liquid, thereby improving its subsequent polymerization reaction activity and chemical stability, and enhancing its responsiveness under the action of an electric field. The polymeric liquid in the composite ammonia water contains polyvalent cations, which can electrostatically adsorb carbon dioxide that is a dipole. Cerium nitrate hexahydrate can promote the formation of internal cavities in the polymeric liquid through swelling and generate oxygen vacancies on the surface, providing more CO2 adsorption sites. The polymeric liquid and ammonia water work synergistically, utilizing the nucleophilic reactivity of ammonia water and the abundant hydrogen bond structure in the polymeric liquid to achieve efficient and rapid capture of carbon dioxide.

[0009] Step 3: Decarbonization and CO2 Collection a) Ammonia-rich solution depressurization desorption regeneration: The ammonia-rich solution that has absorbed CO2 in step 2 is sent to a desorption tower and desorbed under reduced pressure for 30-40 minutes at a pressure of -0.05 to -0.10 MPa and a temperature of 30-50℃ to obtain a mixed desorbed gas containing CO2 and ammonia, as well as regenerated ammonia water; the regenerated ammonia water is returned to step 2 for recycling. b) Electrolytic desorption and ammonia recovery of the composite ammonia-rich solution: The mixed desorbed gas obtained in step a) is passed from bottom to top into the composite ammonia-rich solution that has absorbed CO2 in step 2, while the composite ammonia-rich solution is electrolyzed; the electrolysis treatment is as follows: 20-30wt% water is added to the composite ammonia-rich solution, and the solution is treated at a voltage of 20-30V for 10-20 minutes; In this process, electrolysis promotes the desorption of CO2 in the rich solution of composite ammonia water, while the polymer liquid undergoes reversible expansion to release the CO2 captured inside. The composite ammonia water selectively absorbs ammonia gas in the mixed desorbed gas to generate ammonia water, thus completing ammonia recovery while desorbing CO2. The desorbed CO2 gas is discharged from the top of the tower, dried and collected to obtain a high-purity carbon dioxide product. The regenerated composite ammonia water is returned to step 2 for recycling.

[0010] The beneficial effects of this invention are as follows: This invention provides a simple and efficient process for capturing carbon dioxide using ammonia water for decarbonization. After electrostatic pretreatment of the waste gas, it undergoes two-stage absorption via primary ammonia water absorption and secondary composite ammonia water absorption, capturing a large amount of carbon dioxide in a single stage. Subsequently, the ammonia-containing desorbed gas generated from the depressurized desorption of the primary ammonia-rich solution is directly used in the electrolytic desorption regeneration process of the secondary composite ammonia-rich solution. On one hand, the composite ammonia water absorbs the ammonia in the desorbed gas, achieving in-situ ammonia recovery without the need for an additional ammonia recovery device, thus avoiding secondary pollution. On the other hand, the electrolytic treatment enhances the desorption of CO2 in the composite ammonia-rich solution and promotes the adsorption of ammonia by the polymer liquid, achieving efficient regeneration of the composite ammonia water. The carbon dioxide obtained by this invention has high purity, effectively preventing ammonia leakage, and the absorbent can be recycled. It solves the problems of ammonia escape, low product purity, and the need for additional ammonia recovery processes in existing carbon dioxide capture technologies, making it suitable for the resource utilization of carbon dioxide from industrial waste gas. Attached Figure Description

[0011] Figure 1 This is a comparison graph showing the ammonia concentration before and after electrolysis of the composite ammonia water in Example 1 and Comparative Example 4; Figure 2 This is a comparison chart of the cumulative CO2 capture amount of the composite ammonia water in Example 1 and Comparative Example 3 at different absorption reaction times; Figure 3 This is a comparison chart of the CO2 saturation absorption of ammonia water and compound ammonia water in Examples 1, 2, and 3. Detailed Implementation

[0012] The present invention will be further described in detail below through specific implementation examples and accompanying drawings. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of protection of the present invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art fall within the scope of the appended claims.

[0013] Unless otherwise specified, all raw materials and reagents used in this invention are commercially available reagents.

[0014] Example 1 A process for carbon dioxide capture using ammonia water for decarbonization Step 1: Electrostatic pressurization treatment of carbon-containing waste gas for 12 minutes at an electrostatic intensity of 15 kV / m and a pressure of 0.035 MPa; Step 2: The treated waste gas is subjected to primary absorption and secondary absorption in sequence; Primary absorption: The waste gas is passed from bottom to top through the ammonia absorption tower and reacted countercurrently with the ammonia water treated by microwave radiation; The ammonia solution is ammonia solution with a mass concentration of 30% that has been treated with microwave radiation at a power of 400W for 75s. Secondary absorption: The tail gas after primary absorption is passed from top to bottom through the composite ammonia water absorption tower, where it reacts with the composite ammonia water in a countercurrent flow. The composite ammonia solution is made by adding 8 wt% polymeric liquid to an ammonia solution with a mass concentration of 13%. The polymer liquid was prepared by mixing dimethyl diallyl ammonium chloride, cerium nitrate hexahydrate and plasma-activated ionic liquid in a mass ratio of 13:4:33, and then reacting and polymerizing them under vacuum conditions at a temperature of 65°C for 2 hours. The plasma-activated ionic liquid was obtained by treating 1-propyl-1-methylpiperidine phosphate dihydrogen salt in a plasma with a processing voltage of 80 kV, a frequency of 25 Hz, and a power of 38 kW for 15 min. Step 3: The ammonia-rich solution that absorbed CO2 in Step 2 is sent to the desorption tower and desorbed under reduced pressure at a pressure of -0.08 MPa and a temperature of 40°C for 35 minutes to obtain a mixed desorbed gas containing CO2 and ammonia, as well as regenerated ammonia. The regenerated ammonia is returned to Step 2 for recycling. The above-mentioned mixed desorbed gas is passed from bottom to top into the composite ammonia water rich solution that absorbed CO2 in step 2, while 25wt% water is added to the composite ammonia water rich solution. Electrolysis is performed at 25V for 15 minutes. After the electrolysis is completed, the desorbed CO2 gas is discharged from the top of the tower, dried and collected to obtain a high-purity carbon dioxide product. The regenerated composite ammonia water is returned to step 2 for recycling.

[0015] Example 2 A process for carbon dioxide capture using ammonia water for decarbonization Step 1: Electrostatically pressurize the carbon-containing waste gas for 8 minutes at an electrostatic intensity of 10 kV / m and a pressure of 0.030 MPa; Step 2: The treated waste gas is subjected to primary absorption and secondary absorption in sequence, as in Example 1; The ammonia solution is ammonia solution with a mass concentration of 20% that has been treated with microwave radiation at a power of 300W for 60s. The composite ammonia solution is made by adding 7wt% polymeric liquid to a 10% ammonia solution. The polymer liquid was prepared by mixing dimethyl diallyl ammonium chloride, cerium nitrate hexahydrate and plasma-activated ionic liquid in a mass ratio of 11:3:31, and then reacting and polymerizing them under vacuum conditions at a temperature of 60°C for 2 hours. The plasma-activated ionic liquid was obtained by treating 1-propyl-1-methylpiperidine dihydrogen phosphate in a plasma with a treatment voltage of 50 kV, a frequency of 20 Hz, and a power of 35 kW for 10 min. Step 3: The ammonia-rich solution that absorbed CO2 in Step 2 is sent to the desorption tower and desorbed under reduced pressure at a pressure of -0.05MPa and a temperature of 30℃ for 30 minutes to obtain a mixed desorbed gas containing CO2 and ammonia, as well as regenerated ammonia. The regenerated ammonia is returned to Step 2 for recycling. The above-mentioned mixed desorbed gas is passed from bottom to top into the composite ammonia water rich solution that has absorbed CO2 in step 2, while 20wt% water is added to the composite ammonia water rich solution. Electrolysis is performed at 20V for 10 minutes. After the electrolysis is completed, the desorbed CO2 gas is discharged from the top of the tower, dried and collected to obtain a high-purity carbon dioxide product. The regenerated composite ammonia water is returned to step 2 for recycling.

[0016] Example 3 A process for carbon dioxide capture using ammonia water for decarbonization Step 1: The carbon-containing waste gas is subjected to electrostatic pressurization treatment for 14 minutes at an electrostatic intensity of 20kV / m and a pressure of 0.040 MPa; Step 2: The treated waste gas is subjected to primary absorption and secondary absorption in sequence, as in Example 1; The ammonia solution is an ammonia solution with a mass concentration of 40% that has been subjected to microwave radiation treatment at a power of 500W for 90s. The composite ammonia solution is made by adding 10 wt% polymeric liquid to an ammonia solution with a mass concentration of 15%. The polymer liquid was prepared by mixing dimethyl diallyl ammonium chloride, cerium nitrate hexahydrate and plasma-activated ionic liquid in a mass ratio of 15:5:35, and then reacting and polymerizing them under vacuum conditions at a temperature of 70°C for 3 hours. The plasma-activated ionic liquid was obtained by treating 1-propyl-1-methylpiperidine phosphate dihydrogen salt in a plasma with a treatment voltage of 100kV, a frequency of 30Hz, and a power of 40kW for 20min. Step 3: The ammonia-rich solution that absorbed CO2 in Step 2 is sent to the desorption tower and desorbed under reduced pressure at a pressure of -0.10 MPa and a temperature of 50°C for 40 minutes to obtain a mixed desorbed gas containing CO2 and ammonia, as well as regenerated ammonia. The regenerated ammonia is returned to Step 2 for recycling. The above-mentioned mixed desorbed gas is passed from bottom to top into the composite ammonia water rich solution that has absorbed CO2 in step 2, while 30wt% water is added to the composite ammonia water rich solution. Electrolysis is performed at 30V for 20 minutes. After the electrolysis is completed, the desorbed CO2 gas is discharged from the top of the tower, dried and collected to obtain a high-purity carbon dioxide product. The regenerated composite ammonia water is returned to step 2 for recycling.

[0017] Example 4 A process for carbon dioxide capture using ammonia water for decarbonization Step 1: Electrostatically pressurize the carbon-containing waste gas for 8 minutes at an electrostatic intensity of 10 kV / m and a pressure of 0.040 MPa; Step 2: The treated waste gas is subjected to primary absorption and secondary absorption in sequence, as in Example 1; The ammonia solution is ammonia solution with a mass concentration of 40% that has been treated with microwave radiation at a power of 400W for 80s. The composite ammonia solution is made by adding 7wt% polymeric liquid to a 10% ammonia solution. The polymer liquid was prepared by mixing dimethyl diallyl ammonium chloride, cerium nitrate hexahydrate and plasma-activated ionic liquid in a mass ratio of 15:3:35, and then reacting and polymerizing them under vacuum conditions at a temperature of 60°C for 2 hours. The plasma-activated ionic liquid was obtained by treating 1-propyl-1-methylpiperidine phosphate dihydrogen salt in a plasma with a treatment voltage of 100kV, a frequency of 20Hz, and a power of 40kW for 10min. Step 3: The ammonia-rich solution that absorbed CO2 in Step 2 is sent to the desorption tower and desorbed under reduced pressure at a pressure of -0.10 MPa and a temperature of 30°C for 30 minutes to obtain a mixed desorbed gas containing CO2 and ammonia, as well as regenerated ammonia. The regenerated ammonia is returned to Step 2 for recycling. The above-mentioned mixed desorbed gas is passed from bottom to top into the composite ammonia water rich solution that has absorbed CO2 in step 2, while 30wt% water is added to the composite ammonia water rich solution. Electrolysis is performed at 20V for 20 minutes. After the electrolysis is completed, the desorbed CO2 gas is discharged from the top of the tower, dried and collected to obtain a high-purity carbon dioxide product. The regenerated composite ammonia water is returned to step 2 for recycling.

[0018] Example 5 A process for carbon dioxide capture using ammonia water for decarbonization Step 1: The carbon-containing waste gas is subjected to electrostatic pressurization treatment for 14 minutes at an electrostatic intensity of 20kV / m and a pressure of 0.030 MPa; Step 2: The treated waste gas is subjected to primary absorption and secondary absorption in sequence, as in Example 1; The ammonia solution is ammonia solution with a mass concentration of 20% that has been treated with microwave radiation at a power of 400W for 60s. The composite ammonia solution is made by adding 10 wt% polymeric liquid to an ammonia solution with a mass concentration of 15%. The polymer liquid was prepared by mixing dimethyl diallyl ammonium chloride, cerium nitrate hexahydrate and plasma-activated ionic liquid in a mass ratio of 11:5:31, and then reacting and polymerizing them under vacuum conditions at a temperature of 70°C for 3 hours. The plasma-activated ionic liquid was obtained by treating 1-propyl-1-methylpiperidine phosphate dihydrogen salt in a plasma with a treatment voltage of 50 kV, a frequency of 30 Hz, and a power of 35 kW for 20 min. Step 3: The ammonia-rich solution that absorbed CO2 in Step 2 is sent to the desorption tower and desorbed under reduced pressure at a pressure of -0.05MPa and a temperature of 50℃ for 40 minutes to obtain a mixed desorbed gas containing CO2 and ammonia, as well as regenerated ammonia water. The regenerated ammonia water is returned to Step 2 for recycling. The above-mentioned mixed desorbed gas is passed from bottom to top into the composite ammonia water rich solution that has absorbed CO2 in step 2. At the same time, 20wt% water is added to the composite ammonia water rich solution, and electrolysis is performed at 30V for 10 minutes. After the electrolysis is completed, the desorbed CO2 gas is discharged from the top of the tower, dried and collected to obtain a high-purity carbon dioxide product. The regenerated composite ammonia water is returned to step 2 for recycling.

[0019] Example 6 A process for carbon dioxide capture using ammonia water for decarbonization Step 1: The carbon-containing waste gas is subjected to electrostatic pressurization treatment for 10 minutes at an electrostatic intensity of 12kV / m and a pressure of 0.032 MPa; Step 2: The treated waste gas is subjected to primary absorption and secondary absorption in sequence, as in Example 1; The ammonia solution is an ammonia solution with a mass concentration of 22% after being treated with microwave radiation at a power of 500W for 90s. The composite ammonia solution is made by adding 8 wt% polymeric liquid to an ammonia solution with a mass concentration of 11%. The polymer liquid was prepared by mixing dimethyl diallyl ammonium chloride, cerium nitrate hexahydrate and plasma-activated ionic liquid in a mass ratio of 12:4:32, and then reacting and polymerizing them under vacuum conditions at a temperature of 65°C for 2 hours. The plasma-activated ionic liquid was obtained by treating 1-propyl-1-methylpiperidine phosphate dihydrogen salt in a plasma with a treatment voltage of 60 kV, a frequency of 25 Hz, and a power of 35 kW for 20 min. Step 3: The ammonia-rich solution that absorbed CO2 in Step 2 is sent to the desorption tower and desorbed under reduced pressure at a pressure of -0.08 MPa and a temperature of 35°C for 30 minutes to obtain a mixed desorbed gas containing CO2 and ammonia, as well as regenerated ammonia. The regenerated ammonia is returned to Step 2 for recycling. The above-mentioned mixed desorbed gas is passed from bottom to top into the composite ammonia water rich solution that has absorbed CO2 in step 2, while 30wt% water is added to the composite ammonia water rich solution. Electrolysis is performed at 25V for 10 minutes. After the electrolysis is completed, the desorbed CO2 gas is discharged from the top of the tower, dried and collected to obtain a high-purity carbon dioxide product. The regenerated composite ammonia water is returned to step 2 for recycling.

[0020] Example 7 A process for carbon dioxide capture using ammonia water for decarbonization Step 1: The carbon-containing waste gas is subjected to electrostatic pressurization treatment for 13 minutes at an electrostatic intensity of 18kV / m and a pressure of 0.035 MPa; Step 2: The treated waste gas is subjected to primary absorption and secondary absorption in sequence, as in Example 1; The ammonia solution is ammonia solution with a mass concentration of 35% that has been treated with microwave radiation at a power of 400W for 80s. The composite ammonia solution is made by adding 9 wt% polymeric liquid to an ammonia solution with a mass concentration of 14%. The polymer liquid was prepared by mixing dimethyl diallyl ammonium chloride, cerium nitrate hexahydrate and plasma-activated ionic liquid in a mass ratio of 14:4:34, and then reacting and polymerizing them under vacuum conditions at a temperature of 60°C for 2 hours. The plasma-activated ionic liquid was obtained by treating 1-propyl-1-methylpiperidine phosphate dihydrogen salt in a plasma with a treatment voltage of 90 kV, a frequency of 25 Hz, and a power of 38 kW for 20 min. Step 3: The ammonia-rich solution that absorbed CO2 in Step 2 is sent to the desorption tower and desorbed under reduced pressure at a pressure of -0.09 MPa and a temperature of 45°C for 30 minutes to obtain a mixed desorbed gas containing CO2 and ammonia, as well as regenerated ammonia. The regenerated ammonia is returned to Step 2 for recycling. The above-mentioned mixed desorbed gas is passed from bottom to top into the composite ammonia water rich solution that has absorbed CO2 in step 2, while 28wt% water is added to the composite ammonia water rich solution. Electrolysis is performed at 30V for 20 minutes. After the electrolysis is completed, the desorbed CO2 gas is discharged from the top of the tower, dried and collected to obtain a high-purity carbon dioxide product. The regenerated composite ammonia water is returned to step 2 for recycling.

[0021] Example 8 A process for carbon dioxide capture using ammonia water for decarbonization Step 1: The carbon-containing waste gas is subjected to electrostatic pressurization treatment for 9 minutes at an electrostatic intensity of 12kV / m and a pressure of 0.038 MPa; Step 2: The treated waste gas is subjected to primary absorption and secondary absorption in sequence, as in Example 1; The ammonia solution is ammonia solution with a mass concentration of 35% after being treated with microwave radiation at a power of 400W for 90s. The composite ammonia solution is made by adding 8 wt% polymeric liquid to an ammonia solution with a mass concentration of 12%. The polymer liquid was prepared by mixing dimethyl diallyl ammonium chloride, cerium nitrate hexahydrate and plasma-activated ionic liquid in a mass ratio of 14:3:32, and then reacting and polymerizing them under vacuum conditions at a temperature of 70°C for 2 hours. The plasma-activated ionic liquid was obtained by treating 1-propyl-1-methylpiperidine phosphate dihydrogen salt in a plasma with a treatment voltage of 60 kV, a frequency of 30 Hz, and a power of 35 kW for 15 min. Step 3: The ammonia-rich solution that absorbed CO2 in Step 2 is sent to the desorption tower and desorbed under reduced pressure at a pressure of -0.06 MPa and a temperature of 40°C for 35 minutes to obtain a mixed desorbed gas containing CO2 and ammonia, as well as regenerated ammonia. The regenerated ammonia is returned to Step 2 for recycling. The above-mentioned mixed desorbed gas is passed from bottom to top into the composite ammonia water rich solution that has absorbed CO2 in step 2, while 20wt% water is added to the composite ammonia water rich solution. Electrolysis is performed at 30V for 15 minutes. After the electrolysis is completed, the desorbed CO2 gas is discharged from the top of the tower, dried and collected to obtain a high-purity carbon dioxide product. The regenerated composite ammonia water is returned to step 2 for recycling.

[0022] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 only performs electrostatic dust removal in the pretreatment process, without pressurization, while other aspects remain unchanged.

[0023] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that Comparative Example 2 does not subject the ammonia water to microwave radiation treatment.

[0024] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that no plasma-modified ionic liquid is added to the composite ammonia absorption tower of Comparative Example 3. That is, only dimethyl diallyl ammonium chloride and cerium nitrate hexahydrate are mixed and added to ammonia water, without polymerization reaction, and everything else remains the same.

[0025] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the decarbonization treatment of Comparative Example 4 does not involve electrolysis of the composite ammonia-rich solution, but instead involves conventional heating desorption treatment at a temperature of 80°C. The heating treatment is carried out at a temperature of 80°C, while other aspects remain unchanged.

[0026] The processes and products of the above embodiments and comparative examples were tested, and the results are as follows: 1. Changes in ammonia concentration before and after electrolysis of compound ammonia water The ammonia concentrations of the composite ammonia water before and after electrolysis in Examples 1 and 4 were measured, and the results are as follows: Figure 1 As shown, the ammonia concentration of the composite ammonia water in Example 1 of this invention is significantly higher than that in Comparative Example 4 (conventional heating desorption) after electrolysis, indicating that the composite ammonia water can effectively adsorb the ammonia gas released after ammonia water desorption, thereby recovering ammonia resources; electrolysis can open the polymer groups of the polymer liquid to promote the release of carbon dioxide and promote the generation of ammonia water.

[0027] 2. Comparison of CO2 capture accumulation The cumulative CO2 capture of the composite ammonia water in Examples 1 and 3 at different absorption reaction times was detected, and the results are as follows: Figure 2 As shown, the composite ammonia water of Example 1 of the present invention has a large CO2 absorption capacity and a fast absorption rate, and can efficiently capture carbon dioxide in the exhaust gas in a short time. Comparative Example 3, due to the lack of plasma-activated ionic liquid, lacks the spatial adsorption structure of polymer liquid, and the capture amount is significantly lower than that of Example 1.

[0028] 3. Comparison of CO2 saturation absorption capacity The CO2 saturation absorption capacity of ammonia water and compound ammonia water in Examples 1, 2, and 3 was measured, and the results are as follows: Figure 3 As shown, the ammonia water and composite ammonia water of Example 1 of the present invention have much higher carbon dioxide absorption capacity than those of Comparative Examples 2 and 3. In Comparative Example 2, the ammonia water was not treated with microwave radiation, and the bonding reaction activity between the ammonia water and carbon dioxide was poor. In Comparative Example 3, the composite ammonia water did not contain plasma-activated ionic liquid and did not undergo polymerization reaction, thus lacking the adsorption effect of polymerized liquid and reducing reaction sites, resulting in poor carbon dioxide adsorption.

[0029] 4. Regeneration efficiency test of compound ammonia water The regeneration efficiency of the compound ammonia solution in the examples and comparative examples was tested. The method was as follows: carbon dioxide gas was introduced into the bubbling absorption bottle, a stopwatch was started to start timing, and the gas flow rate was monitored using a soap film flow meter. When the CO2 flow rate at the inlet and outlet was equal, the solution reached saturation. Electrolysis was then performed (heating was performed in the comparative example) for desorption. After desorption was completed, absorption was performed again. The ratio of the two absorption loads was the regeneration efficiency. The results are shown in Table 1.

[0030] Table 1 Regeneration efficiency of compound ammonia water Example 1 98% Example 2 97% Example 3 97% Example 4 97% Example 5 96% Example 6 98% Example 7 97% Example 8 98% Comparative Example 1 97% Comparative Example 2 96% Comparative Example 3 83% Comparative Example 4 85% As shown in Table 1, the regeneration efficiency of the composite ammonia water in Examples 1-8 of this invention all reached over 96%, indicating that the polymeric liquid in the composite ammonia water has spatial adsorption sites and can reversibly expand and release CO2 under electrolysis, exhibiting high recyclability. The regeneration efficiencies of Comparative Examples 1 and 2 are basically equivalent to those of the examples, indicating that electrostatic pressure pretreatment and microwave radiation of ammonia water mainly affect the absorption process and have little impact on the regeneration efficiency. Comparative Example 3, lacking the cavity structure of the polymeric liquid due to the absence of plasma-activated ionic liquid, showed a significant decrease in regeneration efficiency to 83%; Comparative Example 4, using heating desorption instead of electrolysis, resulted in insufficient desorption, with a regeneration efficiency of only 85%, both far lower than the examples.

[0031] 5. CO2 capture efficiency testing The CO2 concentration in the gas before and after treatment was detected using the decarbonization and capture processes of the examples and comparative examples, and the capture efficiency was calculated. The results are shown in Table 2.

[0032] Table 2 CO2 capture efficiency Example 1 900 1.2 99.8% Example 2 900 9.0 99.0% Example 3 900 3.2 99.6% Example 4 900 4.8 99.4% Example 5 900 7.3 99.2% Example 6 900 5.7 99.3% Example 7 900 4.5 99.4% Example 8 900 3.5 99.6% Comparative Example 1 900 98 89.1% Comparative Example 2 900 126 86.0% Comparative Example 3 900 159 82.3% Comparative Example 4 900 146 83.8% As shown in Table 2, the CO2 capture efficiency of Examples 1-8 of this invention all reached over 99.0%, far exceeding that of the comparative examples. Specifically, Comparative Example 1 only removed dust without pressurization, and the CO2 was not activated, resulting in a capture efficiency of 89.1%; Comparative Example 2, the ammonia water was not subjected to microwave radiation, reducing its reactivity and resulting in a capture efficiency of 86.0%; Comparative Example 3, the composite ammonia water lacked core adsorption components, resulting in the lowest capture efficiency (82.3%); Comparative Example 4 used heating desorption, and insufficient regeneration of the absorbent led to a decrease in capture efficiency (83.8%). The capture efficiency ranking is: Comparative Example 3 < Comparative Example 4 < Comparative Example 2 < Comparative Example 1, indicating that the integrity of the composite ammonia water composition has the most critical impact on the capture efficiency.

[0033] 6. CO2 gas purity detection The purity of the CO2 gas collected in the examples and comparative examples was tested, and the results are shown in Table 3. Other gases were mainly N2, O2 and trace amounts of water vapor carried in the raw material gas.

[0034] Table 3 CO2 Gas Purity Examples 1-8 99% 0% margin Comparative Example 1 82% 8% 10% Comparative Example 2 86% 11% 3% Comparative Example 3 80% 15% 5% Comparative Example 4 81% 14% 5% As shown in Table 3, the CO2 obtained in Examples 1-8 of this invention has a purity of up to 99%, and ammonia is undetectable (<0.1%), resulting in pure product gas. In Comparative Example 1, because the CO2 was not activated under pressure, the reaction selectivity was poor, and the purity dropped to 82%. In Comparative Example 2, the ammonia water was not subjected to microwave radiation, resulting in insufficient bonding between free ammonia and CO2, leading to a large amount of ammonia escaping with CO2 during desorption, with an ammonia content of 11%. In Comparative Example 3, the composite ammonia water lacked a polymer liquid, losing its selective adsorption capacity for ammonia, resulting in an ammonia content as high as 15%. In Comparative Example 4, heating desorption was used, reducing the ammonia absorption capacity of the composite ammonia water, with an ammonia content of 14%. Therefore, this invention ensures high purity and low ammonia contamination of the product gas through the synergistic effects of pressurized CO2 activation, microwave activation of ammonia water, ammonia interception by composite ammonia water, and electrolytically enhanced desorption.

Claims

1. A process for carbon dioxide capture using ammonia water for decarbonization, characterized in that, Includes the following steps: Step 1: Treat the carbon-containing waste gas with electrostatic pressure; Step 2: The treated waste gas is subjected to primary absorption and secondary absorption in sequence; The primary absorption process involves passing the waste gas into an ammonia absorption tower to react with ammonia water, absorbing CO2 from the waste gas, and obtaining ammonia-rich solution. The secondary absorption is as follows: the tail gas after the primary absorption is passed into the composite ammonia water absorption tower to react with the composite ammonia water, deeply capture the residual CO2 in the tail gas, and intercept any possible ammonia gas to obtain a rich composite ammonia water solution. The composite ammonia solution is an ammonia solution containing a polymeric liquid, which is prepared from dimethyl diallyl ammonium chloride, cerium nitrate hexahydrate, and a plasma-activated ionic liquid. Step 3: Perform depressurized desorption treatment on the ammonia-rich solution to obtain a mixed desorbed gas containing CO2 and ammonia, as well as regenerated ammonia water; pass the mixed desorbed gas into the composite ammonia-rich solution, and simultaneously electrolyze the composite ammonia-rich solution to collect the desorbed CO2 gas from the composite ammonia-rich solution.

2. The process for carbon dioxide capture using ammonia water as described in claim 1, characterized in that, The electrostatic intensity of the electrostatic pressurization treatment in step 1 is 10-20 kV / m, the pressure is 0.03-0.04 MPa, and the treatment time is 8-14 min.

3. The process for carbon dioxide capture using ammonia water as described in claim 1, characterized in that, The ammonia water mentioned in step 2 is ammonia water with a mass concentration of 20-40% after microwave radiation treatment; the microwave radiation treatment is: heating the ammonia water with microwave irradiation at a power of 300-500W for 60-90s.

4. The process for carbon dioxide capture using ammonia water as described in claim 1, characterized in that, The composite ammonia solution mentioned in step 2 is made by adding 7-10 wt% of the polymeric liquid to an ammonia solution with a mass concentration of 10-15%.

5. The process for carbon dioxide capture using ammonia water as described in claim 1, characterized in that, The polymer liquid is prepared from dimethyl diallyl ammonium chloride, cerium nitrate hexahydrate, and plasma-activated ionic liquid in a mass ratio of 11-15:3-5:31-35.

6. The process for carbon dioxide capture using ammonia water as described in claim 1, characterized in that, The method for preparing the plasma-activated ionic liquid is as follows: 1-propyl-1-methylpiperidine phosphate dihydrogen salt is placed in a plasma treatment device and treated for 10-20 minutes under the conditions of a treatment voltage of 50-100kV, a frequency of 20-30Hz, and a power of 35-40kW.

7. The process for carbon dioxide capture using ammonia water as described in claim 1, characterized in that, The preparation method of the polymer liquid is as follows: dimethyl diallyl ammonium chloride, cerium nitrate hexahydrate and plasma-activated ionic liquid are mixed in proportion and polymerized under vacuum conditions at a temperature of 60-70℃ for 2-3 hours.

8. The process for carbon dioxide capture using ammonia water as described in claim 1, characterized in that, The pressure of the ammonia-rich solution desorption treatment in step 3 is -0.05 to -0.10 MPa, the temperature is 30-50℃, and the time is 30-40 min.

9. The process for carbon dioxide capture using ammonia water as described in claim 1, characterized in that, The electrolytic treatment in step 3 is as follows: 20-30 wt% water is added to the composite ammonia-rich solution, and the solution is treated for 10-20 minutes at a voltage of 20-30V.

10. The process for carbon dioxide capture using ammonia water as described in claim 1, characterized in that, In step 2, the primary absorption involves passing the waste gas from bottom to top through an ammonia water absorption tower, and the secondary absorption involves passing the tail gas after primary absorption from top to bottom through a composite ammonia water absorption tower.

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