System and method for simultaneous removal of sulfur dioxide and carbon dioxide

Abstract

The present application relates to a kind of sulfur dioxide and carbon dioxide cooperative removal system and method, the system includes prewashing tower, multistage circulating absorption tower, interstage cooling device and desorption system communicated sequentially, multistage circulating absorption tower includes slurry pool, first sulfur dioxide high-efficiency removal section, second carbon dioxide main force absorption section, third carbon dioxide reinforced absorption section and fourth water washing absorbent recovery section;The present application is based on multistage circulation, optimizes absorbent formula, while optimizing intelligent control method, not only can effectively improve carbon dioxide capture efficiency, also can significantly reduce sulfur dioxide emission and energy consumption, while reducing the degradation rate of absorbent and metal ion residue, improve the oxidation resistance of absorbent;In addition, the present application also uses advanced intelligent control method, based on real-time data monitoring and multi-factor optimization algorithm, dynamically adjusts system operating parameters, to ensure that the system is stable and efficient under different operating conditions.

Description

Technical Field

[0001] This invention belongs to the field of carbon dioxide emission reduction technology, specifically relating to a system and method for the synergistic removal of sulfur dioxide (SO2) and carbon dioxide (CO2). Background Technology

[0002] With the increasing severity of global climate change, carbon dioxide (CO2), as one of the major greenhouse gases, has become a crucial target for global emission reduction and environmental protection. SO2 (sulfides), a major pollutant in the CO2 emission process, has a significant impact on atmospheric pollution, especially from industrial emission sources such as coal-fired power plants, where the combined emissions of SO2 and CO2 have a significant impact on air quality and human health. Therefore, how to effectively remove CO2 while simultaneously removing SO2 has become a critical technical problem that urgently needs to be solved.

[0003] Currently, Carbon Capture and Storage (CCS) technology is widely used to reduce greenhouse gas emissions. Common CO2 capture methods include physical absorption, chemical absorption, and membrane separation. Among them, chemical absorption is widely used due to its high efficiency and relatively low equipment requirements. However, traditional CO2 capture systems often have the following problems: First, the CO2 capture process is energy-intensive, especially during absorption and desorption, which requires a large amount of thermal energy for CO2 desorption and regeneration; second, the use of absorbents may lead to volatilization and loss, thus affecting capture efficiency; finally, pollutants such as sulfur dioxide (SO2) are not effectively controlled during CO2 capture, especially in emission sources such as coal-fired power plants, where the synergistic removal of SO2 and CO2 faces technical bottlenecks.

[0004] To address the above issues, existing technologies such as MEA (monoethanolamine) absorption and MDEA (N-methyldiethanolamine) absorption, while achieving some progress in CO2 capture, still face several challenges in the synergistic removal of SO2 and CO2 from flue gas. Existing SO2 removal technologies are typically independent of the CO2 capture system, leading to complex system operation and high costs. Furthermore, traditional CO2 capture systems generally employ a single absorbent system, which often fails to achieve ideal results in the synergistic removal of SO2.

[0005] In SO2 removal, common technologies include wet flue gas desulfurization (WFGD) and dry flue gas desulfurization. Wet flue gas desulfurization utilizes limestone slurry to react with SO2 to form calcium sulfate, which has a good desulfurization effect. However, it often requires high temperature and high pressure conditions when treating SO2 in the atmosphere, resulting in high energy consumption. Although dry flue gas desulfurization has lower energy consumption, its desulfurization efficiency is lower, and its effectiveness in treating other pollutants in flue gas is limited.

[0006] Chinese patent CN 113262625 A discloses an integrated ammonia-based desulfurization and decarbonization device and method, which organically integrates decarbonization and desulfurization technologies. It employs acidic desulfurization circulating liquid for ammonia washing, achieving high washing efficiency and solving the ammonia escape problem during decarbonization. The process is simple, producing ammonium sulfate and ammonium bicarbonate fertilizers as byproducts. However, this technology has the following shortcomings: the desulfurization and decarbonization towers are separate, failing to achieve true integration; the system construction and space costs are high; and intelligent and flexible control is lacking, with real-time monitoring and control strategies for the operating parameters of various parts of the system.

[0007] Chinese patent CN 113521966 A discloses a multi-stage cyclic CO2 capture and concentration method based on mass transfer-reaction regulation. Although it adopts a multi-stage cyclic device and the carbon capture rate can reach more than 99%, the absorbent used is a traditional absorbent. The annual degradation rate of the absorbent is as high as 15% to 20%, and the cycle life of the absorbent is relatively short. Traditional absorbents such as monoethanolamine (MEA) generally have a cycle life of several months to one year. Summary of the Invention

[0008] To overcome the shortcomings of existing technologies, this invention provides a system and method for the synergistic removal of sulfur dioxide and carbon dioxide. This system can not only effectively improve carbon dioxide capture efficiency but also significantly reduce sulfur dioxide emissions and energy consumption. At the same time, it reduces the degradation rate and metal ion residue of the absorbent and enhances the antioxidant performance of the absorbent. In addition, this invention also adopts an advanced intelligent control method, which dynamically adjusts the system operating parameters based on real-time data monitoring and multi-factor optimization algorithms to ensure stable and efficient operation of the system under different operating conditions.

[0009] The technical solution adopted in this invention is as follows:

[0010] A method for the synergistic removal of sulfur dioxide and carbon dioxide includes the following steps:

[0011] (1) Cooling the flue gas using a pre-washing tower;

[0012] (2) In the first stage of the high-efficiency sulfur dioxide absorption section of the multi-stage circulating absorption tower, the circulating liquid flow rate of the absorbent is controlled at 40-90 L / h, and the pH range of the absorbent is 7.5-9.5.

[0013] (3) In the secondary and tertiary carbon dioxide absorption sections of the multi-stage circulating absorption tower, carbon dioxide in the flue gas is captured by cooling and using a highly efficient absorbent.

[0014] (4) In the fourth stage of the multi-stage circulating absorption tower, the absorption agent recovery section is washed with water to reduce the escape of the absorption agent and the emission of aerosols.

[0015] (5) In the desorption system, carbon dioxide deep desorption is enhanced by stratified desorption and lean liquid flash evaporation, and the regenerated gas is purified and recovered.

[0016] (6) Optimize the liquid phase diffusion coefficient of carbon dioxide in the synergistic absorption process of carbon dioxide and sulfur dioxide;

[0017] The highly efficient absorbent is a proton migration-enhanced composite amine absorbent or an amino pH buffered composite absorbent. The proton migration-enhanced composite amine absorbent comprises the following components: 2-5 wt.% polyamine activator, 20-35 wt.% main absorbent, 0.5-1.0 wt.% antioxidant, 0.5-1.0 wt.% corrosion inhibitor, 0.5-1.0 wt.% metal scavenger, 0.5-1.0 wt.% defoamer, and the balance being water.

[0018] The amino pH buffered composite absorbent comprises the following components: 0.5–5 wt.% ammonia activator, 15–20 wt.% main absorbent, 0.5–3.0 wt.% ammonia volatilization inhibitor, 0.5–1.0 wt.% antioxidant, 0.5–1.0 wt.% corrosion inhibitor, 0.5–1.0 wt.% metal scavenger, 0.5–1.0 wt.% defoamer, and the balance being water.

[0019] Preferably, in the proton migration-enhanced composite amine absorbent, the polyamine activator includes one or more of hydroxyethyl ethylenediamine, triethylenetetramine, and diethylenetriamine; the main absorbent includes one or more of diethylaminoethanol, N,N-diethylethanolamine, and N-methyldiethanolamine; the antioxidant includes one or more of ethylene glycol, hydroquinone, disodium ethylenediaminetetraacetate, methyl-p-phenylenediamine, sodium thiosulfate, and sodium sulfite; the corrosion inhibitor includes one or more of L-methionine, sodium vanadate, and vanadium pentoxide; the metal capture agent includes one or more of potassium sodium tartrate, sodium molybdate, and sodium metavanadate; and the defoamer includes one or more of polydimethylsiloxane, ethylene glycol siloxane, and polyoxypropylene ethylene glycol glycerol ether.

[0020] In the amino pH buffered composite absorbent, the main absorbent is potassium carbonate, the ammonia volatilization inhibitor includes one or more of potassium lysine, potassium glycine, and potassium proline, the antioxidant includes one or more of ethylene glycol, hydroquinone, disodium ethylenediaminetetraacetate, methyl-p-phenylenediamine, potassium thiosulfate, and potassium sulfite, the corrosion inhibitor includes one or more of potassium vanadate, sodium vanadate, and vanadium pentoxide, the metal capture agent includes one or more of potassium sodium tartrate, sodium molybdate, and sodium metavanadate, and the defoamer includes one or more of polydimethylsiloxane, ethylene glycol siloxane, and polyoxypropylene ethylene glycerol ether.

[0021] As a preferred method, the liquid-phase diffusion coefficient of carbon dioxide is optimized based on a mass transfer-reaction control model. In this model, a competitive absorption factor χ is introduced to correct the liquid-phase diffusion coefficient of carbon dioxide. The corrected liquid-phase diffusion coefficient of carbon dioxide is... It is obtained from the following formula:

[0022]

[0023]

[0024]

[0025]

[0026] in The diffusion coefficient of CO2 in organic amine solution; The mass transfer coefficient is the gas phase mass transfer coefficient. The mass transfer coefficient in the liquid phase; This assumes that the liquid phase mass transfer coefficient is not considered during chemical reactions; It is the constant of Henry's law for CO2; It is a CO2 chemical reaction enhancer;

[0027] By fitting the numerical solution, a nonlinear functional relationship was further established. This relationship quantifies the influence of different concentrations of SO2 on the liquid-phase mass transfer coefficient of CO2 with organic amine concentration, reaction temperature T and SO2 gas phase partial pressure as independent variables.

[0028] The competitive absorption factor χ is a nonlinear function, expressed as:

[0029] χ = 1 - a · exp(-b · C amine + c · T) · [exp(d · P SO2 )] – 1

[0030] Among them, C amine Where is the amine concentration, T is the solution temperature, and P is the concentration of amine. SO2 denoted as ρ, where ρ is the partial pressure of sulfur dioxide in the gas phase, and a, b, c, and d are fitting parameters.

[0031] This invention provides an improved CO2 mass transfer-reaction regulation model that considers the influence of low-concentration SO2 and can more accurately predict the CO2 mass transfer coefficient during the co-absorption of CO2 and SO2. In this model, a competitive absorption factor (χ) is introduced to correct the CO2 diffusion coefficient in the liquid phase, thereby enabling accurate prediction of the CO2 mass transfer process. This correction allows for a more accurate simulation of the influence of SO2 on CO2 mass transfer during co-absorption of CO2 and SO2.

[0032] As a preferred method, intelligent control is employed, which includes the following steps:

[0033] 1. Deploy online monitoring equipment in the absorption section, desorption section, related temperature control devices, and by-product processing unit to collect the following key parameters:

[0034] Flue gas concentration parameters: SO2 concentration C SO2 CO2 concentration C CO2 ;

[0035] Absorption section parameters: Absorbent temperature T abs Circulation volume L abs pH value;

[0036] Desorption section parameters: Desorption tower temperature T des Pressure P des Steam load Q steam ;

[0037] Byproduct formation rate: ammonium sulfate R NH3 and ammonium bicarbonate R HCO3 ;

[0038] II. Establish a multi-factor key parameter model for SO2 removal, CO2 absorption, absorbent recycling and byproduct recovery based on flue gas composition parameters, absorption section operating parameters, desorption section operating parameters and byproduct generation parameters collected by the online monitoring system; and build a model covering the entire process of SO2 removal, CO2 absorption, absorbent recycling and byproduct recovery. By establishing the correlation between absorption efficiency, desorption energy consumption, absorbent loss and byproduct utilization rate, the overall optimization of the synergistic removal process can be achieved.

[0039] The multi-factor regulation key parameter model uses parameters such as SO2 concentration, CO2 concentration, absorbent circulation volume, absorbent temperature, absorbent pH value, desorption tower temperature, desorption tower pressure and steam load in the flue gas as input variables, and SO2 removal efficiency, CO2 capture efficiency, unit capture energy consumption, absorbent escape amount and by-product generation efficiency as evaluation indicators to characterize and predict the system operation status in real time.

[0040] The multi-factor regulation key parameter model includes an energy cost model, a material cost model, and an absorbent escape and capture model. Through multi-objective coupling analysis, a dynamic correlation between the absorption section and the desorption section is established. Under the premise of ensuring efficient and coordinated removal of SO2 and CO2, the system energy consumption is reduced, absorbent loss is reduced, and the efficiency of by-product resource utilization is improved.

[0041] (a) Energy cost model

[0042]

[0043] Where E represents the total energy consumption of the system; This indicates the energy consumption of the absorbent circulation pump; Indicates the energy consumption of the cooling equipment; This indicates the energy consumption of the rich and poor liquid heat exchanger; This indicates the energy consumption of the desorption tower steam load;

[0044] (b) Material cost model

[0045]

[0046] Where C represents the total mass consumption of the system; Indicates the consumption of absorbent; Indicates water resource consumption; This indicates ammonia escape loss; Indicates the consumption of heating agent;

[0047] (c) Absorbent escape and capture model (establishing an optimization objective function)

[0048]

[0049] This represents the decision factor for the objective function. Indicates carbon dioxide capture efficiency; Indicates desorption energy consumption; This indicates the loss due to absorbent escape. Indicates the byproduct formation rate; α, β, γ are weighting factors;

[0050] Third, based on real-time collected operational data, a comprehensive evaluation is conducted on indicators such as energy consumption, material consumption, absorbent loss, and by-product utilization rate. The optimal combination of global operating parameters for the system is obtained through iterative optimization. The optimized parameters include key operating parameters such as absorbent circulation volume, absorbent temperature, absorbent pH value, desorption tower operating temperature, desorption tower operating pressure, steam load, and lean liquid reflux flow rate.

[0051] Under the constraints of meeting the requirements of SO2 removal efficiency, CO2 capture efficiency and absorbent escape control, the dynamic matching of the absorption and desorption processes of the synergistic removal system is realized, and the optimization results are updated in real time according to the changes in operating status, thereby improving the system's operational stability and energy utilization efficiency.

[0052] Establish a comprehensive optimization target for energy consumption, material consumption, and by-product utilization rate:

[0053]

[0054] in, Indicates the utilization rate of by-products;

[0055] Constraints:

[0056] SO2 absorption efficiency: ;

[0057] CO2 absorption efficiency: ;

[0058] Desorption tower operating temperature:

[0059] pH of the absorption solution: ;

[0060] Desorption energy consumption:

[0061] Absorbent escape rate:

[0062] By-product utilization rate: .

[0063] This invention uses a mass transfer-reaction control model to predict the impact of SO2 on CO2 absorption and desorption, and uses a full-process control model of absorption-desorption to comprehensively evaluate the energy quality cost of the system.

[0064] The present invention also provides a system for the above-mentioned synergistic removal of sulfur dioxide and carbon dioxide, the system comprising a pre-washing tower, a multi-stage circulating absorption tower, an inter-stage cooling device and a desorption system connected in sequence, the multi-stage circulating absorption tower comprising a slurry tank, a primary high-efficiency sulfur dioxide removal stage, a secondary main carbon dioxide absorption stage, a tertiary enhanced carbon dioxide absorption stage and a quaternary water washing absorbent recovery stage;

[0065] The first-stage high-efficiency sulfur dioxide removal section removes sulfur dioxide from flue gas by adjusting the solution pH and the circulating liquid volume.

[0066] The secondary carbon dioxide absorption section captures carbon dioxide from the flue gas through cooling and a highly efficient absorbent, achieving a decarbonization efficiency of 99%.

[0067] The three-stage carbon dioxide enhanced absorption stage further improves the carbon dioxide absorption efficiency, with a decarbonization efficiency of over 99.5%.

[0068] The four-stage water washing absorbent recovery section is used to remove aerosols and absorbents, with an aerosol removal efficiency of 99%.

[0069] Preferably, the primary sulfur dioxide high-efficiency removal section includes a primary packing layer, a primary nozzle, and a primary collection tray arranged sequentially from bottom to top; the secondary carbon dioxide main absorption section includes a secondary packing layer, a secondary nozzle, and a secondary collection tray arranged sequentially from bottom to top; the tertiary carbon dioxide enhanced absorption section includes a tertiary packing layer, a tertiary nozzle, and a tertiary collection tray arranged sequentially from bottom to top; the quaternary water washing absorbent recovery section includes a quaternary packing layer, a quaternary nozzle, and an absorption tower demister arranged sequentially from bottom to top; and the bottom of the pre-washing tower is connected to the pre-washing tower nozzle at the top of the pre-washing tower via a washing water circulation pump.

[0070] Preferably, the inter-stage cooling device is located at the inlet of the primary sulfur dioxide absorption section, the secondary carbon dioxide absorption section, the tertiary carbon dioxide absorption section, and the quaternary water washing section. The inter-stage cooling device includes a primary circulating cooler, a secondary circulating pool, a secondary circulating cooler, a tertiary circulating pool, a tertiary circulating cooler, a quaternary circulating pool, and a quaternary circulating cooler. The slurry pool at the bottom of the multi-stage circulating absorption tower is connected to the primary nozzle via a rich liquid pump and a primary circulating cooler, and the primary collection tray is connected to the slurry pool via the secondary circulating pool. The secondary circulating pool is connected to the secondary nozzle via a secondary circulating pump and a secondary circulating cooler, and the secondary collection tray is connected to the secondary circulating pool via the tertiary circulating pool. The tertiary circulating pool is connected to the tertiary nozzle via a tertiary circulating pump and a tertiary circulating cooler, and the tertiary collection tray is connected to the quaternary circulating pool. The quaternary circulating pool is connected to the quaternary nozzle via a quaternary circulating pump and a quaternary circulating cooler.

[0071] Preferably, the desorption system includes a desorption tower, a reboiler, a flash tank, and a compressor. The desorption tower contains, from top to bottom, a desorption tower demister, a desorption tower nozzle, and a desorption tower packing layer. The bottom of the desorption tower is connected to a lean-rich liquor heat exchanger via a lean liquor pump. The lean-rich liquor heat exchanger is also connected to a rich liquor pump, a tertiary circulation tank, and the desorption tower nozzles, respectively. The top of the desorption tower is connected to a gas-liquid separator / concentrator via a cooling mechanism. The gas-liquid separator / concentrator is connected to the reboiler. The reboiler is connected to the flash tank via a pressure reducer. The flash tank is connected to the lower part of the desorption tower via a compressor. The bottom of the desorption tower is also connected to the flash tank and the reboiler, respectively.

[0072] Preferably, the top of the multi-stage circulating absorption tower is connected to the integrated wet electro-washing tower. The upper part of the integrated wet electro-washing tower is equipped with wet electro-washing nozzles and an electrostatic generator. The electrostatic generator is connected to a high-voltage DC power supply. The lower part of the integrated wet electro-washing tower is connected to the wet electro-washing nozzles through a wet electro-washing circulating pump and a wet electro-washing cooler.

[0073] Preferably, the slurry pool at the bottom of the multi-stage circulating absorption tower is connected to an ammonium bisulfate solid-liquid separator via a rich liquid pump, and the ammonium bisulfate solid-liquid separator is connected to an ammonium bisulfate packer via an ammonium bisulfate dryer; the bottom of the secondary packing layer is connected to an ammonium bicarbonate solid-liquid separator, and the ammonium bicarbonate solid-liquid separator is connected to an ammonium bicarbonate packer via an ammonium bicarbonate dryer.

[0074] This invention is based on an amino-based pH-buffered composite absorbent system that can be directly utilized in desulfurization and decarbonization byproduct processes, wherein:

[0075] During the desulfurization process, the generated ammonium sulfate solution is introduced into the ammonium sulfate post-treatment system. After evaporation and crystallization, the solution undergoes solid-liquid separation. The wet ammonium sulfate is dried and packaged into products, or directly produced as ammonium sulfate products.

[0076] During the decarbonation process, the resulting ammonium bicarbonate solution is sent to an evaporation crystallization device. After solid-liquid separation, the wet ammonium bicarbonate is dried and packaged as a product, or it is produced directly as an ammonium bicarbonate product.

[0077] In the removal system, different absorption sections of the absorption tower are equipped with inter-section cooling devices to maintain a constant solution temperature within the tower. This solves the problems of reduced CO2 absorption capacity and absorbent escape caused by solvent temperature rise during the reaction. These inter-section cooling devices are installed at the inlets of the primary SO2 absorption section, the secondary CO2 absorption section, the tertiary CO2 absorption section, and the quaternary water washing section to ensure that the tower temperature remains within the optimized range, improving CO2 absorption efficiency and reducing solvent evaporation loss.

[0078] Following the decarbonization stage, a wet electrostatic scrubbing integrated tower is employed. Through the interception effect of the liquid film and packing material, some large-particle aerosols are removed. The scrubbing and collection stage effectively removes gaseous absorbent components and promotes aerosol aggregation and growth. Combined with the electrostatic collection stage, efficient recovery of multiphase escape absorbent components is further achieved, significantly improving the recovery efficiency of the absorbent in the CO2 capture process.

[0079] Furthermore, increasing the heat load on the reboiler enhances the deep desorption of CO2. Adjusting the CO2 load of the absorbent lean solution can increase the CO2 circulation capacity and reduce the energy consumption of the desorption process, thereby optimizing the performance of the capture system.

[0080] To further improve desorption efficiency, a flash tank is installed at the reboiler outlet to evaporate the high-temperature lean liquor from the reboiler outlet. The secondary steam generated in the flash tank is recompressed by a compressor before entering the desorption tower, thereby increasing the flow rate of high-temperature regeneration gas and promoting the CO2 desorption process. This technology significantly reduces energy consumption in the CO2 desorption process and improves the overall energy efficiency of the system.

[0081] This invention employs an inter-stage cooling device to maintain a constant temperature, increasing the reboiler's heat load to achieve deep CO2 desorption, thereby improving CO2 circulation capacity and reducing energy consumption. By introducing a low-temperature, cold, rich liquid stream and a stratified desorption structure, heat from the regeneration gas is recovered, and the latent heat of vaporization is utilized in stages to further reduce the reboiler's heat load. A flash tank and compressor are also included to promote CO2 desorption and reduce energy consumption.

[0082] Through the above design, the absorption and desorption efficiencies of the removal system are significantly improved, while the desorption energy consumption is reduced. It has broad industrial application prospects and is particularly suitable for energy efficiency optimization in large-scale CO2 capture and regeneration processes.

[0083] This invention optimizes operating conditions and combines them with a CO2 liquid-phase diffusion coefficient model to increase the total CO2 capture efficiency to over 99.5%, reduce desorption energy consumption to 2.0 GJ / t CO2, decrease the annual degradation rate of the absorbent from 15%–20% in traditional absorbent formulations to below 5%, and extend the cycle life of the absorbent to over 3 years.

[0084] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0085] 1. Establish a synergistic removal and desorption system for SO2 and CO2. This synergistic removal system for SO2 and CO2 effectively solves the problems of reduced CO2 absorption capacity and absorbent escape through a multi-stage absorption and desorption process.

[0086] 2. Based on polyamines as activators, a proton migration-enhanced composite amine absorbent was developed. By applying this proton migration-enhanced composite absorbent, the total CO2 capture efficiency can reach over 99.5%, and the CO2 desorption energy consumption is reduced to 2.0 GJ / tCO2.

[0087] 3. Based on K2CO3 as the main component and the addition of ammonia volatilization inhibitors, an ammonia (NH3)-based pH buffer composite absorbent was developed. It can effectively inhibit ammonia escape, increase the concentration of free ammonia in each absorption stage, improve the absorption rate and capacity, and reduce the CO2 desorption energy consumption to 2.0 GJ / t CO2.

[0088] 4. This invention optimizes the absorbent formulation, significantly inhibits the degradation rate of the absorbent, and extends its service life. The annual degradation rate of the absorbent is reduced from 15% to 20% in traditional absorbent formulations to below 5%, and the cycle life of the absorbent is extended to more than 3 years.

[0089] 5. In the inorganic amine absorbent system (using NH3-based pH buffer composite absorbent), the ammonium sulfate solution generated during the desulfurization process can be introduced into the ammonium sulfate crystallization system. After evaporation, crystallization, solid-liquid separation, and drying, ammonium sulfate product is formed. The ammonium bicarbonate solution generated during the decarbonization process can be introduced into the ammonium bicarbonate crystallization system. After evaporation and crystallization, the product is formed. This realizes the efficient and direct utilization of by-products, increases economic benefits, and reduces waste liquid discharge.

[0090] 6. Through real-time dynamic optimization using intelligent control methods, combined with a hybrid model of particle swarm optimization and genetic algorithm, the system's operating efficiency and stability are significantly improved. After optimization, energy consumption is reduced by 15%–20% compared to multi-stage circulating carbon capture systems without intelligent control methods, resulting in a significant decrease in carbon capture operating costs. Attached Figure Description

[0091] Figure 1 This is a schematic diagram of the system structure of the present invention;

[0092] Figure 2 This is a schematic diagram of the system structure for the direct utilization of byproducts from the synergistic capture of SO2 and CO2 by the present invention.

[0093] Figure 3 A comparison chart of the absorption efficiency of proton migration-enhanced composite amine absorbent OCS-1 and conventional mixed amines;

[0094] The annotations in the attached figures are explained as follows:

[0095] Figure 1 The structure consists of: 1. Primary packing layer; 2. Primary nozzle; 3. Primary collection tray; 4. Secondary packing layer; 5. Secondary nozzle; 6. Secondary collection tray; 7. Tertiary packing layer; 8. Tertiary nozzle; 9. Tertiary collection tray; 10. Quaternary packing layer; 11. Quaternary nozzle; 12. Absorber demister; 13. Multi-stage circulating absorber; 14. Pre-washing pump; 15. Venturi pre-washing tower; 16. Pre-washing tower nozzle; 17. Slurry tank; 18. Rich liquid pump; 19. Primary circulating cooler; 20. Secondary circulating tank; 21. Secondary circulating pump; 22. Secondary circulating cooler; 23. Tertiary circulating tank; 24. Tertiary circulating pump. 25. Three-stage circulating cooler; 26. Four-stage circulating tank; 27. Four-stage circulating pump; 28. Four-stage circulating cooler; 29. ​​Lean / rich solution heat exchanger; 30. Lean solution pump; 31. Desorption tower nozzle; 32. Desorption tower packing layer; 33. Reboiler; 34. Pressure reducer; 35. Flash tank; 36. Compressor; 37. Cooling mechanism; 38. Gas-liquid separator; 39. Wet electro-hydraulic washing circulating pump; 40. Wet electro-hydraulic washing cooler; 41. Wet electro-hydraulic washing nozzle; 42. High-voltage DC power supply; 43. Integrated wet electro-hydraulic washing tower; 44. Electrostatic generator;

[0096] Figure 2The structure consists of: 1. Primary packing layer; 2. Primary nozzle; 3. Primary collection tray; 4. Secondary packing layer; 5. Secondary nozzle; 6. Secondary collection tray; 7. Tertiary packing layer; 8. Tertiary nozzle; 9. Tertiary collection tray; 10. Quaternary packing layer; 11. Quaternary nozzle; 12. Absorber demister; 13. Multi-stage circulating absorber; 14. Pre-washing pump; 15. Venturi pre-washing tower; 16. Pre-washing tower nozzle; 17. Slurry tank; 18. Rich liquid pump; 19. Primary circulating coolant. 20. Secondary circulating tank; 21. Secondary circulating pump; 22. Secondary circulating cooler; 23. Tertiary circulating tank; 24. Tertiary circulating pump; 25. Tertiary circulating cooler; 26. Quaternary circulating tank; 27. Quaternary circulating pump; 28. Quaternary circulating cooler; 46. Ammonium bisulfate solid-liquid separator; 47. Ammonium bisulfate dryer; 48. Ammonium bisulfate packaging unit; 49. Ammonium bicarbonate solid-liquid separator; 50. Ammonium bicarbonate dryer; 51. Ammonium bicarbonate packaging unit. Detailed Implementation

[0097] The technical solution of the present invention will be further described in detail below through embodiments. These embodiments are for illustrative purposes only and are not intended to limit the present invention. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0098] Example 1

[0099] Reference Figure 1 A sulfur dioxide and carbon dioxide synergistic removal system (based on proton migration enhanced composite amine absorbent OCS-1), the system includes a pre-washing tower, an absorption tower, an inter-stage cooling device and a desorption system, the absorption tower includes a primary high-efficiency sulfur dioxide removal section, a secondary main carbon dioxide absorption section, a tertiary enhanced carbon dioxide absorption section and a quaternary water washing absorbent recovery section.

[0100] The pre-scrubbing tower cools and pre-treats the flue gas, improving the overall operating performance of the system;

[0101] The primary high-efficiency sulfur dioxide removal stage removes sulfur dioxide from flue gas by adjusting the solution pH and circulating liquid volume.

[0102] The secondary carbon dioxide absorption stage captures carbon dioxide from the flue gas through cooling and a highly efficient absorbent.

[0103] The three-stage carbon dioxide enhanced absorption stage further improves the absorption efficiency of carbon dioxide under low temperature conditions.

[0104] The fourth-stage water washing absorbent recovery section is used to remove aerosols and absorbent, reducing escape losses.

[0105] Interstage cooling devices are used to maintain the optimal temperature range of each absorption stage and reduce reaction energy consumption;

[0106] The desorption system, including a desorption tower, reboiler, flash tank and compressor, is used to recover high-purity CO2 and reduce desorption energy consumption.

[0107] The inter-stage cooling device is installed at the inlet of the primary sulfur dioxide absorption section, the secondary carbon dioxide absorption section, the tertiary carbon dioxide absorption section, and the quaternary water washing section to maintain a constant solution temperature inside the tower.

[0108] The flash tank of the desorption system is used to evaporate the high-temperature lean liquid at the outlet of the desorption tower. The secondary steam generated by flash evaporation is compressed by the compressor and reintroduced into the desorption tower.

[0109] In the removal system, different absorption sections of the absorption tower are equipped with inter-section cooling devices to maintain a constant solution temperature within the tower. This solves the problems of reduced CO2 absorption capacity and absorbent escape caused by solvent temperature rise during the reaction. The cooling devices are installed at the inlets of the primary SO2 absorption section, the secondary CO2 absorption section, the tertiary CO2 absorption section, and the quaternary water washing section to ensure that the tower temperature remains within the optimized range, improving CO2 absorption efficiency and reducing solvent evaporation loss.

[0110] Following the decarbonization stage, a wet electrostatic scrubbing integrated tower is employed. Through the interception effect of the liquid film and packing material, some large-particle aerosols are removed. The scrubbing and collection stage effectively removes gaseous absorbent components and promotes aerosol aggregation and growth. Combined with the electrostatic collection stage, efficient recovery of multiphase escape absorbent components is further achieved, significantly improving the recovery efficiency of the absorbent in the CO2 capture process.

[0111] Furthermore, increasing the heat load on the reboiler enhances the deep desorption of CO2. Adjusting the CO2 load of the absorbent lean solution can increase the CO2 circulation capacity and reduce the energy consumption of the desorption process, thereby optimizing the performance of the capture system.

[0112] To further improve desorption efficiency, a flash tank is installed at the reboiler outlet to evaporate the high-temperature lean liquor from the reboiler outlet. The secondary steam generated in the flash tank is recompressed by a compressor before entering the desorption tower, thereby increasing the flow rate of high-temperature regeneration gas and promoting the CO2 desorption process. This technology significantly reduces energy consumption in the CO2 desorption process and improves the overall energy efficiency of the system.

[0113] Through these innovative designs, the absorption and desorption efficiencies of the CO2 capture system have been significantly improved, while desorption energy consumption has been reduced. It has broad industrial application prospects and is particularly suitable for energy efficiency optimization in large-scale CO2 capture and regeneration processes.

[0114] After the flue gas enters the Venturi pre-washing tower 15 and comes into contact with the circulating washing water to remove particulate matter, it enters the multi-stage circulating absorption tower 13. The washing water comes into direct contact with the flue gas after passing through the washing water circulation pump 14 and the pre-washing tower nozzle 16. The particulate matter removal efficiency reaches 95%, the washing water temperature is 25℃, and the flue gas temperature is 55℃.

[0115] The multi-stage circulating absorption tower 13 includes a primary SO2 high-efficiency removal section (primary SO2 absorption section), a secondary CO2 main absorption and liquid phase enrichment section (secondary CO2 absorption section), a tertiary CO2 enhanced absorption section (tertiary CO2 absorption section), and a quaternary water washing absorbent recovery section (quaternary water washing section).

[0116] Flue gas enters the primary SO2 high-efficiency removal section, passing sequentially through the primary packing layer 1, primary nozzle 2, and primary collection tray 3, achieving an SO2 removal efficiency of 99%. The absorbent circulates within the primary SO2 high-efficiency removal system, with the pH controlled at 8.5 and the temperature at 51℃. The absorbent overflowing from the secondary circulation tank 20 is injected into the slurry tank 17. Passing through the rich liquid pump 18 at a liquid-to-gas ratio of 0.87, it comes into counter-current contact with the flue gas after passing through the primary packing layer 1 and falling into the slurry tank 17. Once the liquid level in the slurry tank 17 reaches a certain height, the saturated rich liquid is pumped by the rich liquid pump 18 into the lean-rich liquid heat exchanger 29 and then into the CO2 desorption tower.

[0117] The flue gas enters the secondary CO2 main absorption and liquid phase enrichment section, passing sequentially through the secondary packing layer 4, secondary nozzle 5, and secondary collection tray 6, achieving a decarbonization efficiency of 99%. The absorbent circulates in the secondary CO2 absorption section, with the pH controlled at 8.0 and the temperature at 47℃. The absorbent overflowing from the tertiary circulation tank 23 is injected into the secondary circulation tank 20, and then enters the multi-stage circulating absorption tower through the secondary circulation pump 21, the secondary circulation cooler (two-stage interstage cooler) 22, and the secondary nozzle 5, with a liquid-to-gas ratio of 1.2. After passing through the secondary packing layer 4 and coming into counter-current contact with the flue gas, it falls into the primary collection tray 3 and circulates back to the secondary circulation tank 20. Once the liquid level in the secondary circulation tank 20 reaches a certain height, it overflows into the slurry tank 17.

[0118] The flue gas enters the three-stage CO2 enhanced absorption section, passing sequentially through the three-stage packing layer 7, the three-stage nozzle 8, and the three-stage collection tray 9, achieving a decarbonization efficiency of 99.7%. The absorbent circulates within the three-stage CO2 enhanced absorption section, with the pH controlled at 7.8 and the temperature at 47℃. The absorbent in the three-stage circulating tank 23, after counter-current contact with the flue gas via the three-stage circulating pump 24, the three-stage circulating cooler (three-stage inter-stage cooler) 25, the three-stage nozzle 8, and the three-stage packing layer 7, falls into the two-stage collection tray 6 and circulates back to the three-stage circulating tank 23. Once the liquid level in the three-stage circulating tank 23 reaches a certain height, it overflows into the two-stage circulating tank 20. The lean liquid in the desorption tower is cooled to 63℃ by the lean liquid pump 30 and the lean-rich liquid heat exchanger 29 before returning to the three-stage circulating tank 23.

[0119] The flue gas enters the fourth-stage water washing absorbent recovery section, passing through the fourth-stage packing layer 10 and the fourth-stage nozzle 11 in sequence, with an aerosol removal efficiency of 99%. After passing through the absorber tower demister 12, it enters the wet electro-water washing integrated tower 43. Softened water circulates in the fourth-stage water washing section, with the pH controlled at 9.1 and the temperature at 35℃. Fresh softened water is injected into the fourth-stage circulation tank 26, and enters the absorber tower through the fourth-stage circulation pump 27, the fourth-stage circulation cooler (four-stage inter-stage cooler) 28 and the fourth-stage nozzle 11, where it comes into counter-current contact with the flue gas. The flue gas ratio is 0.6. After passing through the fourth-stage packing layer 10, it falls into the third-stage collection tray 9 and circulates back to the fourth-stage circulation tank 26.

[0120] After desulfurization and decarbonization, the flue gas enters the wet electro-washing integrated tower 43, and is discharged after passing through the wet electro-washing nozzle 41 and the electrostatic generator 44. The amount of absorbent escape is less than 5 ppm. The washing water comes into counter-current contact with the flue gas through the wet electro-washing circulating pump 39, the wet electro-washing cooler 40, and the wet electro-washing integrated tower nozzle 41, and falls back into the water tank.

[0121] The rich absorbent solution enters the desorption tower from the slurry tank 17 via the rich solution pump 18 and the lean and rich solution heat exchanger 29. The rich solution is heated to 97°C at this time, and then desorbed through the desorption tower nozzle 31 and the desorption tower packing layer 32. The desorption temperature is 107°C. The heat source of the desorption heater comes from the 180°C extraction of the intermediate pressure cylinder of the steam turbine. The solution is cooled to 130°C and returned to the water tank.

[0122] The desorbed CO2 is cooled to below the boiling point of CO2 by the demister 45 and cooling mechanism 37 of the desorption tower and then enters the gas-liquid separator 38 to obtain high-purity CO2. Part of the lean liquid and the liquid obtained by cooling at the outlet of the desorption tower enter the reboiler 33 for further desorption. The gas obtained by flash evaporation returns to the desorption tower through the pressure reducing valve 34, flash tank 35, and pressure boosting valve 36, and circulates in reverse contact with the packing layer 32 and nozzle 31 of the desorption tower.

[0123] The method for synergistic removal of sulfur dioxide and carbon dioxide using the above system includes the following steps:

[0124] (1) The flue gas is cooled using a pre-washing tower, and the flue gas temperature is adjusted to 45℃;

[0125] (2) In the first-stage high-efficiency sulfur dioxide absorption section, the circulating liquid volume and pH value of the absorbent are adjusted. The circulating liquid volume is 40-90 L / h, and the pH range of the absorbent is 7.5-9.5.

[0126] (3) In the secondary and tertiary carbon dioxide absorption sections, the temperature is reduced by inter-section cooling and a proton migration enhanced composite amine absorbent is used to improve CO2 absorption efficiency.

[0127] (4) In the fourth-stage water washing absorbent recovery section, fine water washing is used to reduce absorbent escape and aerosol emission;

[0128] (5) In the desorption system, carbon dioxide deep desorption is enhanced by stratified desorption and lean liquid flash evaporation, and the regenerated gas is purified and recovered.

[0129] (6) Based on the mass transfer-reaction regulation model, the liquid phase diffusion coefficient of carbon dioxide in the synergistic absorption process of carbon dioxide and sulfur dioxide is optimized. The competitive absorption factor χ is introduced to correct the liquid phase diffusion coefficient of carbon dioxide in order to improve the mass transfer efficiency.

[0130] This invention provides an improved CO2 mass transfer-reaction model that considers the influence of low-concentration SO2 and can more accurately predict the CO2 mass transfer coefficient during the co-absorption of CO2 and SO2. In this model, a competitive absorption factor (χ) is introduced to correct the CO2 diffusion coefficient in the liquid phase, thereby enabling accurate prediction of the CO2 mass transfer process. This correction allows for a more accurate simulation of the influence of SO2 on CO2 mass transfer during co-absorption of CO2 and SO2.

[0131] Specifically, the corrected CO2 liquid-phase diffusion coefficient is given by the following four equations. Through numerical solution fitting, a nonlinear functional relationship was further established, which quantifies the influence of different SO2 concentrations on the CO2 liquid-phase mass transfer coefficient with organic amine concentration, reaction temperature T, and SO2 gas phase partial pressure as independent variables.

[0132]

[0133]

[0134]

[0135]

[0136] in The diffusion coefficient of CO2 in organic amine solution; The mass transfer coefficient is the gas phase mass transfer coefficient. The mass transfer coefficient in the liquid phase; This assumes that the liquid phase mass transfer coefficient is not considered during chemical reactions; It is the constant of Henry's law for CO2; CO2 chemical reaction enhancer

[0137] Wherein, the competitive absorption factor χ is a nonlinear function, and its expression is:

[0138] χ = 1 - a·exp(-b·C amine +c·T)·[exp(d·P SO2 )] – 1

[0139] Among them, Camine Where is the amine concentration, T is the solution temperature, and P is the concentration of amine. SO2 Let be the partial pressure of SO2 in the gas phase, and a, b, c, and d be the fitting parameters.

[0140] This invention establishes regression equations for CO2 and SO2 concentrations in ammonia solutions and fits the competitive absorption factors of ethanolamine (MEA), methylmonoethanolamine (MMEA), and N-methyldiethanolamine (MDEA) solutions. The resulting relationships can be used to optimize the absorption efficiency in the synergistic absorption process of CO2 and SO2. Table 1 provides the fitted relationships of the competitive absorption factors for MEA, MMEA, and MDEA solutions.

[0141] Table 1 Note: The concentration of amine is mol / L; T is the solution temperature, °C. The partial pressure of SO2 in the gas phase is kPa.

[0142] Preparation of CO2 and SO2 absorbents: A 5 wt.% piperazine PZ / 20 wt.% MDEA solution was used as the CO2 absorbent, and a 1 wt.% PZ / 4 wt.% MDEA solution was used to simulate low-concentration organic amine wash water as the SO2 absorbent (PZ / MDEA). Based on this, a proton migration-enhanced composite amine absorbent OCS-1 was developed using polyamines as activators and tertiary amines as the main absorbent: ① Activator (2 wt.% hydroxyethyl ethylenediamine AEEA, 2 wt.% diethylenetriamine DEAT); ② Main absorbent (20 wt.% diethylaminoethanol DEAE, 10 wt.% diethylaminoethanol DEAT, 10 wt.% diethylaminoethanol DEAT, 10 wt.% diethylaminotriamine ... wt.% N-methyldiethanolamine (MDEA); ③ Antioxidant (0.5 wt.% ethylene glycol EG, 0.5 wt.% hydroquinone HQ); ④ Corrosion inhibitor (0.5 wt.% vanadium pentoxide V2O5); ⑤ Metal scavenger (1 wt.% potassium sodium tartrate KNaC4H4O6); ⑥ Defoamer (0.5 wt.% polydimethylsiloxane); balance: water;

[0143] A 1 wt.% NH3 / 20 wt.% K2CO3 solution was used as the CO2 absorbent, and a 0.6 wt.% ammonia solution was used as the SO2 absorbent to simulate low-concentration NH3 washing water. Based on this, an NH3-based pH-buffered composite absorbent ICS-1 was developed by adding an ammonia volatilization inhibitor: ① Activator (5 wt.% ammonia solution NH3·H2O); ② Main absorbent (20 wt.% potassium carbonate K2CO3); ③ Volatilization inhibitor (2 wt.% potassium lysine K-Lys); ④ Antioxidant (1.0 wt.% hydroquinone HQ, 0.5 wt.% potassium thiosulfate); ⑤ Corrosion inhibitor (0.5 wt.% vanadium pentoxide V2O5); ⑥ Metal scavenger (0.5 wt.% potassium sodium tartrate KNaC4H4O6). Defoamer (0.5 wt.% polydimethylsiloxane); balance: water;

[0144] The absorbents (OCS-1, ICS-1) prepared above are used in the synergistic removal system, and combined with the control of operating parameters, CO2 and SO2 are synergistically removed.

[0145] This invention optimizes operating conditions and combines them with a CO2 liquid-phase diffusion coefficient model to increase the total CO2 capture efficiency to over 99.5% and reduce desorption energy consumption to 2.0 GJ / t CO2.

[0146] Operating parameters include SO2 concentration at the flue gas inlet, circulating liquid volume in the CO2 absorption section, pH value, and temperature.

[0147] 1. Flue gas flow rate 5 m³ / h 3 / h, inlet flue gas temperature 100℃, CO2 concentration 15%, SO2 concentration 1800 mg / m³ 3 2. Pre-washing tower system. Pre-washing cools the simulated flue gas to a wet saturated flue gas temperature of 45°C. 3. Multi-stage circulating absorption tower (circulating zone absorption system). First to third stage CO2 absorption sections: circulating liquid flow rate 48–72 L / h; inter-stage cooling lowers the absorbent temperature to 35°C at each stage; fourth stage water washing section: circulating liquid flow rate 60 L / h; fourth stage water washing water temperature 30°C; rich liquid flow rate 18–72 L / h; circulating cooling water flow rate 48 L / h; circulating cooling water temperature 25°C. 4. Desorption tower system. Desorption tower inlet: rich liquid temperature 90°C; regeneration temperature 108°C; lean liquid flash evaporation pressure 50 kPa.

[0148] CO2 absorption enhancement and liquid-phase enrichment are achieved by lowering the absorbent temperature, increasing the circulating liquid volume, and extending the residence time of the enriched liquid. By adjusting the initial NH3 concentration in the absorbent, the ammonia escape per unit time at the CO2 absorption section outlet can be effectively controlled, reducing the amount of wash water replenishment while ensuring CO2 capture efficiency.

[0149] Based on the requirements of desulfurization products, oxidation / oxidation inhibition treatments are performed. By adding antioxidants such as ethylene glycol (EG), hydroquinone (HQ), and disodium ethylenediaminetetraacetate (EDTA), NH4HSO3 / (NH4)2SO3 products can be obtained, which are important raw materials for the preparation of high-value-added chemical products. (NH4)2SO4 products are prepared by regulating the flow rate of oxidizing air. The desulfurization liquid is periodically discharged to ensure the ammonia / sulfur / water balance of the synergistic removal system.

[0150] This invention is based on the cyclic-partition absorption technology and combined with intelligent control methods. By optimizing operating parameters in real time, it significantly improves the efficiency of SO2 and CO2 synergistic removal, reduces system energy and material consumption, and increases the utilization rate of by-products.

[0151] The method for synergistic removal of sulfur dioxide and carbon dioxide includes three models: energy cost control, material cost control, and absorbent escape control. Multiple online monitoring devices are deployed in each absorption section, mainly distributed in the slurry tank (rich liquid tank), primary SO2 removal section, secondary CO2 absorption section, tertiary CO2 absorption section, quaternary water washing section, desorption tower, flash tank, and integrated wet electro-washing tower.

[0152] The process of synergistic removal of SO2 and CO2 employs intelligent control methods, which specifically include the following steps:

[0153] I. Deploy online monitoring equipment in the absorption sections (SO2 absorption section, CO2 absorption section, water washing section), desorption sections (desorption tower, flash tank), related temperature control devices, and by-product processing units to collect the following key parameters:

[0154] Flue gas concentration parameters: SO2 concentration C SO2 CO2 concentration C CO2 Absorption section parameters: Absorbent temperature T abs Circulation volume L abs pH value; Desorption section parameters: Desorption tower temperature T des Pressure P des Steam load Q steam Byproduct formation rate: ammonium sulfate R NH3 and ammonium bicarbonate R HCO3 .

[0155] By analyzing the operating data of each device and combining it with the equipment design parameters, a parameter data platform covering SO2 and CO2 synergistic absorption-desorption, energy consumption, material consumption, and by-product utilization was established.

[0156] II. Establish a multi-factor regulation key parameter model for the entire absorption-desorption process, and optimize the operating parameters during the absorption and desorption stages. The multi-factor regulation key parameter model includes the following optimization objectives:

[0157] (a) Energy cost model

[0158]

[0159] Where E represents the total energy consumption of the system; This indicates the energy consumption of the absorbent circulation pump; Indicates the energy consumption of the cooling equipment; This indicates the energy consumption of the rich and poor liquid heat exchanger; This indicates the energy consumption of the desorption tower steam load;

[0160] (b) Material cost model

[0161]

[0162] Of which, the total material consumption of system C; Indicates the consumption of absorbent; Indicates water resource consumption; This indicates ammonia escape loss; Indicates the consumption of heating agent;

[0163] (c) Escape absorber trapping model

[0164] Based on a multi-factor regulation model of the absorption-desorption process, an optimization objective function is established:

[0165]

[0166] This represents the decision factor for the objective function. Indicates carbon dioxide capture efficiency; Indicates desorption energy consumption; This indicates the loss due to absorbent escape. Indicates the byproduct formation rate; α, β, γ are weighting factors;

[0167] III. Using particle swarm optimization or ant colony optimization algorithms, comprehensively analyze the multi-factor regulation key parameter model and calculate the globally optimal operating conditions, including:

[0168] Establish a comprehensive optimization target for energy consumption, material consumption, and by-product utilization rate:

[0169]

[0170] in, Indicates the utilization rate of by-products;

[0171] By-product utilization rate definition:

[0172] Ammonium sulfate: ;

[0173] Ammonium bicarbonate: ;

[0174] Constraints:

[0175] SO2 absorption efficiency: ;

[0176] CO2 absorption efficiency: ;

[0177] Desorption tower operating temperature:

[0178] pH of the absorption solution: ;

[0179] Desorption energy consumption:

[0180] Absorbent escape rate:

[0181] By-product utilization rate: .

[0182] Based on real-time monitoring data, the system achieves real-time feedback and dynamic control through the following steps:

[0183] Data Acquisition: Real-time acquisition of key parameters, including absorption section temperature, pH, desorption section operating pressure, and steam load; Model Calculation: Calculation of objective function values ​​based on acquired data to determine the optimization direction for the current operating state; Parameter Adjustment: Dynamic adjustment of key parameters such as absorbent circulation rate and desorption tower steam input using Particle Swarm Optimization (PSO) or Ant Colony Optimization (ACO) algorithms; Optimization Feedback: Improvement of synergistic removal efficiency of SO2 and CO2 through adjusted parameter combinations, reduction of energy and material consumption, and maximization of byproduct generation efficiency.

[0184] A comparison of the absorption efficiency of proton migration-enhanced composite amine absorbent OCS-1 with that of conventional mixed amines (PZ / MDEA) is as follows: Figure 3 As shown, the absorption rate of each stage of the system was significantly improved after using the new absorbent.

[0185] 5000m 3 After being treated by the above system, the flue gas with a flow rate of / h achieves a desulfurization efficiency of 99%, a decarbonization efficiency of 99.7%, and a desorption energy consumption of less than 2.0 GJ / t CO2.

[0186] Degradation rate comparison: After 1000 hours of continuous operation in simulated flue gas (containing 1800 ppm SO2 and 4% O2), the total amine concentration of OCS-1 decreased by only 5.8%, while that of traditional MEA absorbent decreased by 22.3%. HPLC analysis showed no significant thermal decomposition products (such as ethylenediamine and nitrosamines) in OCS-1, while the nitrosamine formation in the MEA system reached 120 ppm.

[0187] Long-term operating data: After 12 months of continuous operation, the CO2 absorption capacity retention rate of OCS-1 in a coal-fired power plant was still 93.5%, while that of the traditional MEA system dropped to below 62%, requiring frequent replacement of the absorbent.

[0188] Example 2

[0189] The difference between this embodiment and Embodiment 1 is that the absorbent components used are different.

[0190] The absorbent consists of: ① activator (3 wt.% hydroxyethyl ethylenediamine AEEA); ② main absorbent (10 wt.% diethylaminoethanol DEAE, 20 wt.% N-methyldiethanolamine MDEA); ③ antioxidant (0.5 wt.% ethylene glycol EG); ④ corrosion inhibitor (0.5 wt.% vanadium pentoxide V2O5); ⑤ metal scavenger (1 wt.% potassium sodium tartrate KNaC4H4O6); ⑥ defoamer (0.5 wt.% polydimethylsiloxane); the balance being water. After 12 months of continuous operation in a coal-fired power plant, the absorbent's capacity retention rate was 89.6%, and the total amine concentration decreased by 8.9%.

[0191] Example 3

[0192] Using ICS-1 absorbent

[0193] Reference Figure 2 A system for the synergistic removal of SO2 and CO2 includes a pre-washing tower, a multi-stage circulating absorption tower, an inter-stage cooling device, and a desorption system connected in sequence. The multi-stage circulating absorption tower includes a slurry tank, a primary high-efficiency sulfur dioxide removal section, a secondary main carbon dioxide absorption section, a tertiary enhanced carbon dioxide absorption section, and a quaternary water washing absorbent recovery section.

[0194] The primary sulfur dioxide high-efficiency removal section includes a primary packing layer 1, a primary nozzle 2, and a primary collection tray 3 arranged sequentially from bottom to top; the secondary carbon dioxide main absorption section includes a secondary packing layer 4, a secondary nozzle 5, and a secondary collection tray 6 arranged sequentially from bottom to top; the tertiary carbon dioxide enhanced absorption section includes a tertiary packing layer 7, a tertiary nozzle 8, and a tertiary collection tray 9 arranged sequentially from bottom to top; the quaternary water washing absorbent recovery section includes a quaternary packing layer 10, a quaternary nozzle 11, and an absorption tower demister 12 arranged sequentially from bottom to top; the bottom of the pre-washing tower is connected to the pre-washing tower nozzle 16 at the top of the pre-washing tower 15 via a washing water circulation pump 14.

[0195] The inter-stage cooling device is located at the inlet of the primary sulfur dioxide absorption section, the secondary carbon dioxide absorption section, the tertiary carbon dioxide absorption section, and the quaternary water washing section. The inter-stage cooling device includes a primary circulating cooler 19, a secondary circulating pool 20, a secondary circulating cooler 22, a tertiary circulating pool 23, a tertiary circulating cooler 25, a quaternary circulating pool 26, and a quaternary circulating cooler 28. The slurry pool at the bottom of the multi-stage circulating absorption tower is connected to the primary nozzle 2 via a rich liquid pump 18 and the primary circulating cooler 19. A primary collection tray 3... The secondary circulation tank 20 is connected to the slurry tank 17; the secondary circulation tank 20 is connected to the secondary nozzle 5 through the secondary circulation pump 21 and the secondary circulation cooler 22, and the secondary collection tray 6 is connected to the secondary circulation tank 20 through the tertiary circulation tank 23; the tertiary circulation tank 23 is connected to the tertiary nozzle 8 through the tertiary circulation pump 24 and the tertiary circulation cooler 25, and the tertiary collection tray 9 is connected to the quaternary circulation tank 26, and the quaternary circulation tank 26 is connected to the quaternary nozzle 11 through the quaternary circulation pump 27 and the quaternary circulation cooler 28.

[0196] The slurry pool 17 at the bottom of the multi-stage circulating absorption tower is connected to the ammonium bisulfate solid-liquid separator 46 via the rich liquid pump 18. The ammonium bisulfate solid-liquid separator 46 is connected to the ammonium bisulfate packer 48 via the ammonium bisulfate dryer 47. The bottom of the secondary packing layer 4 is connected to the ammonium bicarbonate solid-liquid separator 49. The ammonium bicarbonate solid-liquid separator 49 is connected to the ammonium bicarbonate packer 51 via the ammonium bicarbonate dryer 50.

[0197] Flue gas enters the absorption system and, after passing through a pre-washing tower located at the front of the multi-stage absorption tower, sequentially enters the first-stage high-efficiency sulfur dioxide removal section, the second-stage main carbon dioxide absorption section, the third-stage enhanced carbon dioxide absorption section, and the fourth-stage water washing absorbent recovery section. The rich liquid is pumped through an ammonium bisulfate solid-liquid separator and an ammonium bisulfate dryer before entering an ammonium bisulfate baler for baling to obtain ammonium bisulfate fertilizer. The carbon-containing absorbent rich liquid at the bottom of the decarbonization section is pumped to an ammonium bicarbonate solid-liquid separator and an ammonium bicarbonate dryer before entering an ammonium bicarbonate baler for baling to obtain ammonium bicarbonate fertilizer.

[0198] Based on mass transfer and reaction mechanism models and operational data, a multi-factor control model for key parameters of the entire absorption-by-product recovery and utilization process is established to optimize the operational parameters of the absorption and desorption stages. The model includes the following optimization objectives:

[0199] (a) Energy cost model

[0200]

[0201] (b) Material cost model

[0202]

[0203] (c) Escape absorber trapping model

[0204]

[0205] Using Particle Swarm Optimization (PSO) or Ant Colony Optimization (ACO) algorithms, a comprehensive analysis of key parameter models is conducted to calculate the globally optimal operating conditions, including:

[0206] Establish a comprehensive optimization target for energy consumption, material consumption, absorbent escape, and byproduct utilization rate:

[0207]

[0208] Constraints:

[0209] SO2 absorption efficiency: ;

[0210] CO2 absorption efficiency: ;

[0211] pH of the absorption solution: ;

[0212] By-product utilization rate:

[0213] In addition to N2 and some O2, the flue gas from power plants burning high-sulfur coal contains about 10% water vapor, 12% to 18% CO2 and 1000 to 1500 ppm SO2.

[0214] Flue gas enters the Venturi pre-scrubber 15, is scrubbed with circulating water, and then enters the multi-stage circulating absorption tower 13. The flue gas then enters the primary SO2 high-efficiency removal section, passing sequentially through the primary packing layer 1, primary nozzle 2, and primary collection tray 3, achieving an SO2 removal efficiency of 99%. The absorbent circulates in the primary SO2 high-efficiency removal system, with the pH controlled at 8.5 and the temperature at 51℃. The absorbent overflowing from the secondary circulating tank 20 is injected into the slurry tank 17. Through the rich liquid pump 19, at a liquid-to-gas ratio of 0.89, it passes through the primary packing layer 4 and comes into counter-current contact with the flue gas before falling into the slurry tank 17. Once the liquid level in the slurry tank 17 reaches a certain height, the saturated rich liquid is pumped by the rich liquid pump 18 to the ammonium bisulfate solid-liquid separator 46 for solid-liquid separation. After solid-liquid separation, it enters the ammonium bisulfate dryer 47 for drying and is packaged by the ammonium bisulfate baler 48, resulting in an ammonium bisulfate product purity of 98%.

[0215] The flue gas enters the secondary CO2 main absorption section, passing sequentially through the secondary packing layer 4, secondary nozzle 5, and secondary collection tray 6, achieving a decarbonization efficiency of 99%. The absorbent circulates within the secondary CO2 absorption section, with the pH controlled at 8.0 and the temperature at 47℃. The absorbent overflowing from the tertiary circulation tank 23 is injected into the secondary circulation tank 20, and then enters the multi-stage circulation absorption tower via the secondary circulation pump 21, secondary circulation cooler 22, and secondary nozzle 5, with a liquid-to-gas ratio of 1.4. After passing through the secondary packing layer 4 and coming into counter-current contact with the flue gas, it falls into the primary collection tray 3 and circulates back to the secondary circulation tank 20. The decarbonized rich liquid at the bottom of the secondary packing layer 4 is pumped through the ammonium bicarbonate solid-liquid separator 49, ammonium bicarbonate dryer 50, and ammonium bicarbonate baler 51 to obtain the by-product, ammonium bicarbonate fertilizer, with a product purity of 98%.

[0216] The flue gas enters the three-stage CO2 enhanced absorption section, passing sequentially through the three-stage packing layer 7, the three-stage nozzle 8, and the three-stage collection tray 9, achieving a decarbonization efficiency of 99.5%. The absorbent circulates within the three-stage CO2 enhanced absorption section, with the pH controlled at 8.0 and the temperature at 47℃. The absorbent in the three-stage circulation tank 23, after counter-current contact with the flue gas via the three-stage circulation pump 24, the three-stage circulation cooler 25, the three-stage nozzle 8, and the three-stage packing layer 7, falls into the two-stage collection tray 6 and circulates back to the three-stage circulation tank 23. Once the liquid level in the three-stage circulation tank 23 reaches a certain height, it overflows into the two-stage circulation tank 20.

[0217] The flue gas enters the fourth-stage water washing absorbent recovery section, passing through the fourth-stage packing layer 10 and the fourth-stage nozzle 11 in sequence, achieving an aerosol removal efficiency of 99%. After passing through the absorber demister 12, it enters the wet electro-water washing integrated tower 43. Softened water circulates in the fourth-stage water washing section, with the pH controlled at 9.1 and the temperature at 35℃. Fresh softened water is injected into the fourth-stage circulation tank 26, and enters the absorber tower through the fourth-stage circulation pump 27, the fourth-stage circulation cooler 28, and the fourth-stage nozzle 11, where it comes into counter-current contact with the flue gas. The flue gas ratio is 0.6. After passing through the fourth-stage packing layer 10, it falls into the third-stage collection tray 9 and circulates back to the fourth-stage circulation tank 26.

[0218] 6000m 3 After the flue gas is treated by the above system, the desulfurization efficiency is 99%, the decarbonization efficiency is 99.5%, the by-product ammonium sulfate is 0.512 t / h, and the by-product ammonium bicarbonate is 19.3 t / h, which is 17% higher than the existing by-product recovery system.

[0219] After 12 months of continuous operation at a coal-fired power plant, the capacity retention rate of the ICS-1 absorbent was 93.9%.

[0220] Example 4

[0221] The difference between this embodiment and Embodiment 3 is that the absorbent composition is different.

[0222] The absorbent components are: ① Activator (5 wt.% ammonia (NH3·H2O); ② Main absorbent (20 wt.% potassium carbonate (K2CO3); ③ Volatilization inhibitor (1 wt.% potassium glycinate (K-Lys); ④ Antioxidant (1.0 wt.% disodium ethylenediaminetetraacetate, 0.5 wt.% potassium thiosulfate); ⑤ Corrosion inhibitor (0.5 wt.% potassium vanadate); ⑥ Metal scavenger (0.5 wt.% potassium sodium tartrate (KNaC4H4O6)). Defoamer (0.5 wt.% polydimethylsiloxane); balance: water; after 12 months of continuous operation in a coal-fired power plant, the capacity retention rate of the absorbent was 87.5%, which was lower than that of the ICS-1 absorbent.

[0223] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for the synergistic removal of sulfur dioxide and carbon dioxide, characterized in that, Includes the following steps: (1) Cooling the flue gas using a pre-washing tower; (2) In the first stage of the high-efficiency sulfur dioxide absorption section of the multi-stage circulating absorption tower, the circulating liquid flow rate of the absorbent is controlled at 40-90 L / h, and the pH range of the absorbent is 7.5-9.

5. (3) In the secondary and tertiary carbon dioxide absorption sections of the multi-stage circulating absorption tower, carbon dioxide in the flue gas is captured by cooling and using a highly efficient absorbent. (4) In the fourth stage of the multi-stage circulating absorption tower, the absorption agent recovery section is washed with water to reduce the escape of the absorption agent and the emission of aerosols. (5) In the desorption system, carbon dioxide deep desorption is enhanced by stratified desorption and lean liquid flash evaporation, and the regenerated gas is purified and recovered. (6) Optimize the liquid phase diffusion coefficient of carbon dioxide in the synergistic absorption process of carbon dioxide and sulfur dioxide; The highly efficient absorbent is a proton migration-enhanced composite amine absorbent or an amino pH buffered composite absorbent. The proton migration-enhanced composite amine absorbent comprises the following components: 2-5 wt.% polyamine activator, 20-35 wt.% main absorbent, 0.5-1.0 wt.% antioxidant, 0.5-1.0 wt.% corrosion inhibitor, 0.5-1.0 wt.% metal scavenger, 0.5-1.0 wt.% defoamer, and the balance being water. The amino pH buffered composite absorbent comprises the following components: 0.5–5 wt.% ammonia activator, 15–20 wt.% main absorbent, 0.5–3.0 wt.% ammonia volatilization inhibitor, 0.5–1.0 wt.% antioxidant, 0.5–1.0 wt.% corrosion inhibitor, 0.5–1.0 wt.% metal scavenger, 0.5–1.0 wt.% defoamer, and the balance being water.

2. The method for synergistic removal of sulfur dioxide and carbon dioxide according to claim 1, characterized in that, In the proton migration-enhanced composite amine absorbent, the polyamine activator includes one or more of hydroxyethyl ethylenediamine, triethylenetetramine, and diethylenetriamine; the main absorbent includes one or more of diethylaminoethanol, N,N-diethylethanolamine, and N-methyldiethanolamine; the antioxidant includes one or more of ethylene glycol, hydroquinone, disodium ethylenediaminetetraacetate, methyl-p-phenylenediamine, sodium thiosulfate, and sodium sulfite; the corrosion inhibitor includes one or more of L-methionine, sodium vanadate, and vanadium pentoxide; the metal capture agent includes one or more of potassium sodium tartrate, sodium molybdate, and sodium metavanadate; and the defoamer includes one or more of polydimethylsiloxane, ethylene glycol siloxane, and polyoxypropylene ethylene glycol glycerol ether. In the amino pH buffered composite absorbent, the main absorbent is potassium carbonate, the ammonia volatilization inhibitor includes one or more of potassium lysine, potassium glycine, and potassium proline, the antioxidant includes one or more of ethylene glycol, hydroquinone, disodium ethylenediaminetetraacetate, methyl-p-phenylenediamine, potassium thiosulfate, and potassium sulfite, the corrosion inhibitor includes one or more of potassium vanadate, sodium vanadate, and vanadium pentoxide, the metal capture agent includes one or more of potassium sodium tartrate, sodium molybdate, and sodium metavanadate, and the defoamer includes one or more of polydimethylsiloxane, ethylene glycol siloxane, and polyoxypropylene ethylene glycerol ether.

3. The method for synergistic removal of sulfur dioxide and carbon dioxide according to claim 1, characterized in that, In step (6), the liquid-phase diffusion coefficient of carbon dioxide is optimized based on the mass transfer-reaction control model. In the mass transfer-reaction control model, a competitive absorption factor χ is introduced to correct the liquid-phase diffusion coefficient of carbon dioxide. The corrected liquid-phase diffusion coefficient of carbon dioxide is... It is obtained from the following formula: in The diffusion coefficient of CO2 in organic amine solution; The mass transfer coefficient is the gas phase mass transfer coefficient. The mass transfer coefficient in the liquid phase; This assumes that the liquid phase mass transfer coefficient is not considered during chemical reactions; It is the constant of Henry's law for CO2; It is a CO2 chemical reaction enhancer; The competitive absorption factor χ is a nonlinear function, expressed as: χ = 1 - a · exp(-b · C amine + c · T) · [exp(d · P SO2 )] – 1 Among them, C amine Where is the amine concentration, T is the solution temperature, and P is the concentration of amine. SO2 denoted as ρ, where ρ is the partial pressure of sulfur dioxide in the gas phase, and a, b, c, and d are fitting parameters.

4. The method for synergistic removal of sulfur dioxide and carbon dioxide according to claim 1, characterized in that, The control method employs intelligent regulation, which specifically includes the following steps:

1. Deploy online monitoring equipment in the absorption section, desorption section, related temperature control devices, and by-product processing unit to collect the following key parameters: Flue gas concentration parameters: SO2 concentration C SO2 CO2 concentration C CO2 ; Absorption section parameters: Absorbent temperature T abs Circulation volume L abs pH value; Desorption section parameters: Desorption tower temperature T des Pressure P des Steam load Q steam ; Byproduct formation rate: ammonium sulfate R NH3 and ammonium bicarbonate R HCO3 ; II. Establish a multi-factor control key parameter model covering the entire process of SO2 removal, CO2 absorption, absorbent recycling and by-product recovery based on flue gas composition parameters, absorption section operation parameters, desorption section operation parameters and by-product generation parameters collected by the online monitoring system; The multi-factor regulation key parameter model includes an energy cost model, a material cost model, and an absorbent escape and capture model: (a) Energy cost model Where E represents the total energy consumption of the system; This indicates the energy consumption of the absorbent circulation pump; Indicates the energy consumption of the cooling equipment; This indicates the energy consumption of the rich and poor liquid heat exchanger; This indicates the energy consumption of the desorption tower steam load; (b) Material cost model Where C represents the total mass consumption of the system; Indicates the consumption of absorbent; Indicates water resource consumption; This indicates ammonia escape loss; Indicates the consumption of heating agent; (c) Absorbent escape and trapping model This represents the decision factor for the objective function. Indicates carbon dioxide capture efficiency; Indicates desorption energy consumption; This indicates the loss due to absorbent escape. Indicates the byproduct formation rate; α, β, γ are weighting factors; Third, based on real-time collected operational data, a comprehensive evaluation is conducted on indicators including energy consumption, material consumption, absorbent loss, and by-product utilization rate. The optimal combination of global operating parameters for the system is obtained through iterative optimization. The optimized parameters include absorbent circulation volume, absorbent temperature, absorbent pH value, desorption tower operating temperature, desorption tower operating pressure, steam load, and lean liquid return flow rate. Establish a comprehensive optimization target for energy consumption, material consumption, absorbent loss, and by-product utilization rate: in, Indicates the utilization rate of by-products; Constraints: SO2 absorption efficiency: ; CO2 absorption efficiency: ; Desorption tower operating temperature: pH of the absorption solution: ; Desorption energy consumption: Absorbent escape rate: By-product utilization rate: .

5. A system for the synergistic removal of sulfur dioxide and carbon dioxide according to any one of claims 1-4, characterized in that, The system includes a pre-washing tower, a multi-stage circulating absorption tower, an inter-stage cooling device, and a desorption system connected in sequence. The multi-stage circulating absorption tower includes a slurry tank, a primary high-efficiency sulfur dioxide removal section, a secondary main carbon dioxide absorption section, a tertiary enhanced carbon dioxide absorption section, and a quaternary water washing absorbent recovery section. The first-stage high-efficiency sulfur dioxide removal section removes sulfur dioxide from flue gas by adjusting the solution pH and the circulating liquid volume. The secondary carbon dioxide absorption section captures carbon dioxide from the flue gas through cooling and a highly efficient absorbent, achieving a decarbonization efficiency of 99%. The three-stage carbon dioxide enhanced absorption stage further improves the carbon dioxide absorption efficiency, with a decarbonization efficiency of over 99.5%. The four-stage water washing absorbent recovery section is used to remove aerosols and absorbents, with an aerosol removal efficiency of 99%.

6. The sulfur dioxide and carbon dioxide synergistic removal system according to claim 5, characterized in that, The primary sulfur dioxide high-efficiency removal section includes a primary packing layer, a primary nozzle, and a primary collection tray arranged sequentially from bottom to top; the secondary carbon dioxide main absorption section includes a secondary packing layer, a secondary nozzle, and a secondary collection tray arranged sequentially from bottom to top; the tertiary carbon dioxide enhanced absorption section includes a tertiary packing layer, a tertiary nozzle, and a tertiary collection tray arranged sequentially from bottom to top; the quaternary water washing absorbent recovery section includes a quaternary packing layer, a quaternary nozzle, and an absorption tower demister arranged sequentially from bottom to top; the bottom of the pre-washing tower is connected to the pre-washing tower nozzles at the top of the pre-washing tower via a washing water circulation pump.

7. The sulfur dioxide and carbon dioxide synergistic removal system according to claim 6, characterized in that, The inter-stage cooling device is located at the inlet of the primary sulfur dioxide absorption section, the secondary carbon dioxide absorption section, the tertiary carbon dioxide absorption section, and the quaternary water washing section. The inter-stage cooling device includes a primary circulating cooler, a secondary circulating pool, a secondary circulating cooler, a tertiary circulating pool, a tertiary circulating cooler, a quaternary circulating pool, and a quaternary circulating cooler. The slurry pool at the bottom of the multi-stage circulating absorption tower is connected to the primary nozzle via a rich liquid pump and a primary circulating cooler. The primary collection tray is connected to the slurry pool via a secondary circulating pool. The secondary circulating pool is connected to the secondary nozzle via a secondary circulating pump and a secondary circulating cooler. The secondary collection tray is connected to the secondary circulating pool via a tertiary circulating pool. The tertiary circulating pool is connected to the tertiary nozzle via a tertiary circulating pump and a tertiary circulating cooler. The tertiary collection tray is connected to the quaternary circulating pool. The quaternary circulating pool is connected to the quaternary nozzle via a quaternary circulating pump and a quaternary circulating cooler.

8. The sulfur dioxide and carbon dioxide synergistic removal system according to claim 7, characterized in that, The desorption system includes a desorption tower, a reboiler, a flash tank, and a compressor. The desorption tower contains, from top to bottom, a desorption tower demister, a desorption tower nozzle, and a desorption tower packing layer. The bottom of the desorption tower is connected to a lean-rich liquor heat exchanger via a lean liquor pump. The lean-rich liquor heat exchanger is also connected to a rich liquor pump, a tertiary circulation tank, and the desorption tower nozzles. The top of the desorption tower is connected to a gas-liquid separator / concentrator via a cooling mechanism. The gas-liquid separator / concentrator is connected to the reboiler. The reboiler is connected to the flash tank via a pressure reducer. The flash tank is connected to the lower part of the desorption tower via a compressor. The bottom of the desorption tower is also connected to the flash tank and the reboiler.

9. The sulfur dioxide and carbon dioxide synergistic removal system according to claim 5, characterized in that, The top of the multi-stage circulating absorption tower is connected to the integrated wet electro-washing tower. The upper part of the integrated wet electro-washing tower is equipped with wet electro-washing nozzles and an electrostatic generator. The electrostatic generator is connected to a high-voltage DC power supply. The lower part of the integrated wet electro-washing tower is connected to the wet electro-washing nozzles through a wet electro-washing circulating pump and a wet electro-washing cooler.

10. The sulfur dioxide and carbon dioxide synergistic removal system according to claim 7, characterized in that, The slurry pool at the bottom of the multi-stage circulating absorption tower is connected to the ammonium bisulfate solid-liquid separator via a rich liquid pump. The ammonium bisulfate solid-liquid separator is connected to the ammonium bisulfate packer via an ammonium bisulfate dryer. The bottom of the secondary packing layer is connected to the ammonium bicarbonate solid-liquid separator. The ammonium bicarbonate solid-liquid separator is connected to the ammonium bicarbonate packer via an ammonium bicarbonate dryer.

Images