Ammonia desulfurization and decarbonization integrated process

Abstract

The invention discloses an ammonia desulfurization and decarburization integrated process, belongs to the technical field of industrial waste gas treatment and resource utilization, and aims to solve the problems of low decarburization efficiency, system scaling, ammonia escape and the like caused by slow CO2 absorption and secondary release in the prior art. Gradient absorption and double-circulation coupling are realized in a tower: flue gas firstly passes through an upper decarburization section, and carbon-rich liquid then flows into a lower desulfurization section; and CO2 replaced by desulfurization is returned to the decarburization section through a diversion structure in the tower for reabsorption. The decarburization efficiency and the CO2 absorption rate are remarkably improved, scaling and ammonia escape are synergistically inhibited, and efficient and stable operation is achieved.

Description

Technical Field

[0001] This invention belongs to the field of industrial waste gas treatment and resource utilization technology, specifically involving an integrated ammonia-based desulfurization and decarbonization process. Background Technology

[0002] Against the backdrop of the global strategy of "peaking carbon and achieving carbon neutrality," the coordinated control of sulfur dioxide (SO2) and carbon dioxide (CO2) in flue gas emissions from coal-fired power plants, steel, and chemical industries has become a key technological direction for air pollution control and climate change mitigation. The ammonia process, due to its unique advantages such as a wide range of absorbent sources, high desulfurization efficiency, no secondary solid waste pollution, and the ability of ammonium sulfate as a byproduct to be used as a high-value fertilizer, has attracted much attention in the field of flue gas purification and is considered one of the ideal technological routes for achieving the coordinated removal of SO2 and CO2.

[0003] However, when extending the traditional ammonia-based desulfurization process to integrated desulfurization and decarbonization applications, existing technologies face a series of mutually restrictive technical bottlenecks. First, there is a serious inherent technical contradiction: the secondary release of CO2. In the integrated absorption tower, the ammonium carbonate product of the upper decarbonization reaction (CO2 + 2NH3·H2O → (NH4)2CO3) is precisely the reactant of the lower desulfurization reaction (SO2 + (NH4)2CO3 → (NH4)2SO3 + CO2). Because sulfurous acid is stronger than carbonic acid, the captured CO2 is re-released in the desulfurization section, creating an ineffective "capture and release" cycle, resulting in extremely low net decarbonization efficiency. Second, the absorption kinetics of CO2 are slow, with its hydration reaction in aqueous solution being the rate-limiting step in the entire absorption process. To compensate for this deficiency, existing processes must employ large absorption towers and extremely high liquid-to-gas ratios, leading to high equipment investment and operating energy consumption. Third, the system suffers from poor operational stability, with severe equipment scaling and ammonia escape problems coexisting. In the integrated process, multiple ammonium salts coexist in the liquid phase, and their solubility is sensitive to temperature, making them prone to precipitation, scaling, and clogging of equipment. At the same time, the high operating temperature and intense mass transfer process exacerbate the volatilization loss of ammonia, causing not only economic losses but also corrosion of downstream equipment and PM2.5 aerosol pollution.

[0004] In summary, although the integrated ammonia-based desulfurization and decarbonization process has broad application prospects, existing technologies still fall short in addressing several core technical challenges, including secondary CO2 release, slow absorption kinetics, system scaling, and ammonia escape, failing to achieve a balance between technological and economic efficiency and environmental benefits. Therefore, there is an urgent need to develop a novel process technology that can fundamentally enhance CO2 absorption and collaboratively solve various operational problems, thereby removing obstacles to the large-scale industrial application of the integrated ammonia-based process and providing strong technical support for achieving deep purification of industrial flue gas and carbon emission reduction targets. Summary of the Invention

[0005] To address the technical challenges of existing integrated ammonia-based desulfurization and decarbonization processes, such as slow CO2 absorption kinetics, low decarbonization efficiency due to secondary CO2 release, easy scaling and clogging, and severe ammonia escape, this invention aims to provide an integrated ammonia-based desulfurization and decarbonization process. This process, through the introduction of a novel biomimetic catalyst and optimized process flow design, significantly improves the CO2 absorption rate while effectively solving the problem of secondary CO2 release, and synergistically suppresses scaling and ammonia escape, achieving efficient, stable, and long-term operation of the system.

[0006] The objective of this invention can be achieved through the following technical solutions: An integrated ammonia-based desulfurization and decarbonization process includes the following steps: Step S1, Flue Gas Conditioning Pretreatment: High-temperature flue gas containing SO2 and CO2 from boilers or industrial kilns is sent to a cooling tower (or quench tower) after dust removal by a bag filter or electrostatic precipitator. Inside the cooling tower, circulating cooling water is sprayed and brought into direct contact with the high-temperature flue gas, rapidly reducing its temperature to 35-45°C while simultaneously increasing its humidity, resulting in pretreated flue gas that meets the requirements for subsequent absorption.

[0007] Step S2, Preparation of biomimetic catalytic absorption liquid: The biomimetic catalytic absorption liquid is composed of ammonia water with a mass fraction of 15% to 20%, scale inhibitor and dispersant polyepoxysuccinic acid (PESA), and zinc-centered biomimetic catalytic polymer (ZBCP).

[0008] The core component, zinc-centered biomimetic catalytic polymer (ZBCP), is prepared through the following steps: Raw material preparation: Polymer backbone: Polyethyleneimine (PEI), molecular weight 10000–25000 g / mol, industrial grade; Multidentate ligand: 2-amino-2-methyl-1-propanol (AMP), analytical grade; Zinc source: Zinc acetate (Zn(CH3COO)2), analytical grade; Solvent: Anhydrous ethanol, analytical grade. All of the above raw materials can be purchased from conventional chemical markets.

[0009] Preparation steps: Step 1: Activation of polymer backbone: Add 100 parts by weight of polyethyleneimine (PEI) to 500 parts by weight of anhydrous ethanol, and stir with a magnetic stirrer at room temperature (25°C) for 30 minutes until PEI is completely dissolved to form a homogeneous and transparent PEI-ethanol solution.

[0010] Step 2: Grafting of polydentate ligands: 20 parts by mass of 2-amino-2-methyl-1-propanol (AMP) were slowly added dropwise to the above PEI-ethanol solution to obtain mixed solution A. Mixed solution A was transferred to a three-necked flask equipped with a reflux condenser and heated in a constant temperature water bath at 60°C with continuous stirring for 6 hours. During this process, the amino group of AMP underwent a nucleophilic substitution reaction with some primary or secondary amine groups on the PEI chain, stably grafting AMP onto the PEI backbone through covalent bonds, resulting in an AMP-functionalized polyethyleneimine solution (PEI-AMP).

[0011] Step 3: Introduction of the Zinc Center: In a separate container, dissolve 10 parts by mass of zinc acetate in 100 parts by mass of anhydrous ethanol to prepare an ethanol solution of zinc acetate. Slowly add this ethanol solution of zinc acetate to the AMP-functionalized polyethyleneimine solution obtained in Step 2 to obtain mixed solution B. Continue stirring the mixed solution B in a constant temperature water bath at 50°C for 2 hours. During this process, zinc ions (Zn2+) coordinate at multiple points with the AMP grafted on PEI (providing hydroxyl oxygen and amino nitrogen) and spatially adjacent amino nitrogen atoms on the PEI backbone, forming a stable biomimetic catalytic active center with a structure similar to the active center of carbonic anhydrase.

[0012] Step 4: Post-processing: After the reaction is complete, cool the mixed product to room temperature. Place it on a rotary evaporator and distill under reduced pressure at 50°C and vacuum to recover most of the ethanol solvent, obtaining a viscous concentrated product. Dissolve the concentrated product in an appropriate amount of deionized water and transfer it to a dialysis bag with a molecular weight cutoff of 3500 Da. Dialyze with a large amount of deionized water for 48 hours, changing the deionized water every 6-8 hours to thoroughly remove unreacted AMP, zinc acetate, and other small molecule raw materials and byproducts. Pre-freeze the purified product after dialysis in a -80°C freezer, then transfer it to a freeze dryer and freeze-dry for 24 hours to obtain a pure white powdery zinc-centered biomimetic catalytic polymer (ZBCP).

[0013] The zinc-centered biomimetic catalytic polymer (ZBCP) prepared in this invention is a functionalized polymeric catalyst whose structure ingeniously mimics the highly efficient carbonic anhydrase found in nature: using high-molecular-weight polyethyleneimine (PEI) as a backbone, it provides abundant reaction sites and spatial structure; by grafting the multidentate ligand AMP, it creates conditions for the stable binding of the metal center; finally, the introduced zinc ions form a stable coordination structure with the ligand and the nitrogen and oxygen atoms on the PEI backbone, constituting the biomimetic catalytic active center.

[0014] When preparing the absorbent, based on the total mass of the ammonia solution, the preferred addition amount of zinc-centered biomimetic catalytic polymer (ZBCP) is 0.5–2.0 wt%, and the preferred addition amount of polyepoxysuccinic acid (PESA) is 0.05–0.2 wt%.

[0015] Step S3, Gradient absorption and dual-loop coupling: The pretreated flue gas from step S1 is introduced from the bottom of the integrated absorption tower. The absorption tower is a packed tower or a plate tower, which is divided into a desulfurization section and a decarbonization section from bottom to top.

[0016] Decarbonization section: Located at the top of the absorption tower. The fresh biomimetic catalytic absorbent prepared in step S2 is sprayed down from the top of the tower, coming into countercurrent contact with the flue gas flowing upwards. The biomimetic catalytic active centers in the ZBCP greatly accelerate the CO2 hydration reaction rate, essentially creating a "fast track" for CO2 absorption, enabling CO2 to be efficiently captured and converted into bicarbonate / carbonate ions. After the reaction, the biomimetic catalytic absorbent transforms into a carbon-rich absorbent and flows downwards.

[0017] Desulfurization section: Located at the bottom of the absorption tower. The carbon-rich absorbent liquid flowing down from the decarbonization section (mainly composed of ammonium carbonate / ammonium bicarbonate) directly acts as a desulfurizing agent, reacting with the newly entered pretreated flue gas, which has the highest CO2 concentration, in a strong acid-displacement reaction (SO2 + (NH4)2CO3 → (NH4)2SO3 + CO2), efficiently removing SO2 and generating ammonium sulfite / ammonium bisulfite slurry. The CO2 released during this process forms CO2-rich secondary flue gas.

[0018] Dual-circulation coupling: A gas-phase redistribution plate or flow guide hood, or other internal flow guiding structure, is installed between the desulfurization and decarbonization sections. This structure effectively collects the secondary flue gas generated in the desulfurization section and evenly reintroduces it into the lower part of the decarbonization section. This high-concentration CO2 gas rises with the main flue gas and is again captured by the biomimetic catalytic absorbent in the upper decarbonization section. This design constitutes a clever "gas-phase internal circulation," effectively "replacing" the displaced CO2 in situ, fundamentally solving the problem of low net decarbonization efficiency caused by secondary CO2 release.

[0019] Step S4, Oxidation and Crystallization Separation: The sulfite slurry discharged from the bottom of the desulfurization section is pumped into a forced oxidation tank. At 50-55°C, excess compressed air is introduced to efficiently oxidize the ammonium sulfite and ammonium bisulfite in the slurry into ammonium sulfate, which has higher solubility and more stable properties, yielding an ammonium sulfate solution. This solution is then sent to an evaporation crystallization unit for concentration via multi-effect evaporation or MVR evaporation. After cooling and crystallization, solid-liquid separation is performed using a centrifuge. The separated wet crystals are dried using an airflow dryer or a fluidized bed dryer to obtain ammonium sulfate crystals that meet national standards. The centrifugal mother liquor can be returned to the absorption system for recycling.

[0020] Step S5, CO2 Capture and Absorbent Regeneration: The purified flue gas (SO2 and CO2 have been deeply removed) at the top of the decarbonization section is discharged after removing entrained ammonia through a demister and a clean water scrubbing section at the top of the tower. To achieve CO2 capture and utilization, a portion of the carbon-rich absorbent (usually drawn from the middle of the decarbonization section) is diverted to the regeneration tower. In the regeneration tower, it is heated to 95-100°C by steam or other heat sources, causing ammonium bicarbonate and ammonium carbonate to decompose and release high-purity (usually >99%) CO2 gas. This gas, after cooling and dehydration, can be used in chemical synthesis, food industry, oilfield enhanced oil recovery, or geological sequestration. The lean ammonia solution after analysis is cooled and returned to the absorbent preparation tank of step S2, replenished with fresh ammonia, and recycled, realizing the regeneration and closed-loop circulation of the absorbent. Beneficial effects

[0021] (1) The problem of secondary CO2 release is fundamentally solved and the decarbonization efficiency is greatly improved: Through the innovative design of "gradient absorption and dual circulation coupling", the CO2 replaced by the desulfurization process is reintroduced into the decarbonization section for reabsorption through the internal flow structure of the tower, realizing the "zero escape" internal circulation of CO2, and increasing the net decarbonization efficiency of the system from less than 40% in the traditional process to more than 85%.

[0022] (2) Significantly improved CO2 absorption kinetics, reducing equipment investment and operating energy consumption: The original zinc-centered biomimetic catalytic polymer (ZBCP) of this invention has a structure that mimics the active center of carbonic anhydrase, exhibiting extremely high catalytic activity for CO2 hydration reactions. This increases the CO2 absorption rate several times, achieving the same or even higher decarbonization efficiency with a lower liquid-to-gas ratio and a smaller absorption tower volume, thereby significantly reducing equipment investment and pumping energy consumption.

[0023] (3) Synergistic inhibition of system scaling and ammonia escape, resulting in high operational stability: This invention achieves unexpected synergistic effects. On the one hand, ZBCP, as a high molecular polymer, has a long-chain structure that can play a steric hindrance effect in solution, synergistically inhibiting the nucleation and growth of ammonium salt crystals with the scale inhibitor and dispersant PESA, thus significantly extending the continuous operation cycle of the system. On the other hand, the catalytic effect of ZBCP greatly improves the reaction efficiency at low temperatures, allowing the absorption process to be carried out at even lower temperatures (35-45℃), reducing the saturated vapor pressure of ammonia; at the same time, the large number of amine groups on the PEI skeleton has a certain adsorption effect on ammonia molecules, retaining ammonia in the liquid phase like an "ammonia sponge." The combined effect of these two factors reduces the ammonia escape rate by more than 50%.

[0024] (4) It realizes the resource utilization of waste and carbon capture, with significant economic and environmental benefits: This process not only efficiently removes SO2 and CO2 pollutants, but also converts SO2 into high-value-added ammonium sulfate fertilizer and CO2 into high-purity resource products, realizing "turning waste into treasure" and "carbon capture and utilization" (CCU), which has good economic benefits and far-reaching environmental significance. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Furthermore, unless otherwise specified, the raw materials, reagents, or devices used in the following embodiments can be obtained from conventional commercial channels or by existing known methods.

[0026] Simulated flue gas conditions: All examples and comparative examples used simulated flue gas for testing. The total flue gas volume was 50 m³ / h, and the composition (volume ratio) was: SO₂ 1500 ppm, CO₂ 15%, O₂ 6%, and N₂ as the balance. The flue gas temperature after pretreatment was 40°C. The absorption tower was a glass-packed tower with an inner diameter of Φ150 mm and a total height of 4 m. The packing material was Φ25 mm polypropylene Pall rings. The packing layer height in the desulfurization section was 1.2 m, and the packing layer height in the decarbonization section was 1.5 m. The liquid-to-gas ratio was controlled at 15 L / m³.

[0027] Example 1: An integrated ammonia-based desulfurization and decarbonization process, the specific steps of which are as follows: (1) Preparation of zinc-centered biomimetic catalytic polymer (ZBCP): Weigh 100g polyethyleneimine (PEI, molecular weight 10000 g / mol), 20g 2-amino-2-methyl-1-propanol (AMP) and 10g zinc acetate, and carry out the reaction and post-treatment according to steps one, two, three and four of the invention to obtain white powder ZBCP.

[0028] (2) Preparation of biomimetic catalytic absorption solution: Add 0.5 kg (0.5 wt%) of ZBCP obtained in step (1) and 0.05 kg (0.05 wt%) of polyepoxysuccinic acid (PESA) to 100 kg of ammonia water with a mass fraction of 15%, and stir to dissolve evenly.

[0029] (3) Perform integrated desulfurization and decarbonization according to steps S1, S3, S4 and S5 as described in the invention.

[0030] Example 2: Basically the same as Example 1, except that: (2) Preparation of biomimetic catalytic absorption liquid: 1.0 kg (1.0 wt%) of ZBCP prepared in Example 1 and 0.1 kg (0.1 wt%) of PESA were added to 100 kg of ammonia water with a mass fraction of 18%.

[0031] (3) The molecular weight of polyethyleneimine is 20,000 g / mol.

[0032] Example 3: Basically the same as Example 1, except that: (2) Preparation of biomimetic catalytic absorption liquid: 2.0 kg (2.0 wt%) of ZBCP prepared in Example 1 and 0.2 kg (0.2 wt%) of PESA were added to 100 kg of ammonia water with a mass fraction of 20%.

[0033] (3) The molecular weight of polyethyleneimine is 25,000 g / mol.

[0034] Comparative Example 1: This example is essentially the same as Example 2, except that the absorbent is only 100 kg of ammonia water with a mass fraction of 18%, and ZBCP and PESA are not added. This comparative example simulates the traditional integrated ammonia process.

[0035] Comparative Example 2: This example is essentially the same as Example 2, except that the absorbent is 100 kg of ammonia water with a mass fraction of 18% with 0.1 kg (0.1 wt%) of PESA added, and ZBCP is not added. This comparative example is used to examine the effect of adding scale inhibitors and dispersants alone.

[0036] Comparative Example 3: This example is essentially the same as Example 2, except that the absorbent is 100 kg of 18% ammonia water with 1.0 kg (1.0 wt%) of ZBCP added, and PESA is not added. This comparative example is used to examine the effect of adding the biomimetic catalyst alone.

[0037] Test Example 1 Performance tests were conducted on the process operation effects of Examples 1 to 3 and Comparative Examples 1 to 3. The test methods and results are as follows: 1. Performance testing methods: (1) Desulfurization efficiency (η-SO2) and decarbonization efficiency (η-CO2) tests: After the system has been running stably for 2 hours, measurements were taken at the flue gas inlet and outlet of the absorption tower using the same portable flue gas analyzer (Testo 350). Each measurement point was measured three times consecutively, each time for 5 minutes, and the average value was taken. The efficiency calculation formula is: Efficiency (%) = [(Cin - Cout) / Cin] × 100%; Wherein, Cin is the concentration (ppm or %) of SO2 or CO2 in the inlet flue gas, and Cout is the concentration of SO2 or CO2 in the outlet flue gas.

[0038] (2) Ammonia slip rate test: Sampling and analysis were performed on the flue gas duct at the outlet of the absorption tower using the national standard method "Determination of Ammonia in Waste Gas from Stationary Sources - Nessler's Reagent Spectrophotometric Method" (HJ 533-2009). A certain volume of flue gas was collected using an acidic solution absorption bottle, then developed with Nessler's reagent, and the absorbance was measured on a spectrophotometer to calculate the ammonia concentration (mg / m3) in the flue gas.

[0039] (3) Continuous Operation Stability Test: After startup, the total pressure drop at the inlet and outlet of the absorption tower is continuously monitored using a differential pressure gauge. Based on the initial stable pressure drop, the time (h) required for the pressure drop to rise by 50% is recorded. The longer this time, the stronger the system's anti-scaling ability and the more stable its operation. When the pressure drop rises by 50%, it is determined that the system is blocked, and the experiment is stopped.

[0040] 2. Test Results: The performance of each of the above groups of experiments was tested, and the specific data are shown in Table 1: Table 1 Test Results

[0041] 3. Results Analysis: The test results in Table 1 show that: (1) Decarbonization and desulfurization efficiency analysis: The decarbonization efficiency of Comparative Example 1 (traditional ammonia method) was only 35.8%, confirming the severity of the secondary CO2 release problem. After adding ZBCP, the decarbonization efficiency of Comparative Example 3 soared to 85.3%, and the desulfurization efficiency also reached 99.1%. This fully demonstrates that the ZBCP biomimetic catalyst has an excellent catalytic promoting effect on CO2 absorption, and the improved decarbonization efficiency reduces the negative impact on the subsequent desulfurization reaction. Under the combined action of ZBCP and the dual-cycle coupling process, Examples 1-3 all achieved decarbonization efficiencies of over 86%, with a maximum of 91.5%, while maintaining an ultra-high desulfurization efficiency of >99%, significantly better than all comparative examples.

[0042] (2) Ammonia slip rate analysis: The ammonia slip rates of Comparative Examples 1 and 2 were both above 15 mg / m3, which is at a relatively high level. In Comparative Example 3 and Examples 1-3, due to the addition of ZBCP, the absorption reaction could proceed efficiently at a lower temperature, resulting in a significant reduction in ammonia slip rates, all below 9 mg / m3. In particular, Examples 2 and 3 showed ammonia slip rates reduced to 6.2 mg / m3 and 5.1 mg / m3, respectively, representing a reduction of over 60% compared to traditional processes, demonstrating the synergistic effect of this invention in suppressing ammonia slip.

[0043] (3) Continuous Operation Stability Analysis: Comparative Example 1 (without any additives) experienced a sharp increase in pressure drop due to scaling and blockage after only 48 hours of operation. Comparative Example 3 (with ZBCP only) also only operated for 55 hours, indicating that although the catalyst was highly efficient, it could not solve the scaling problem and might even exacerbate scaling due to excessively fast local reaction rates. Comparative Example 2 (with PESA only) had a significantly extended operating time of 650 hours, proving that PESA is an effective scale inhibitor and dispersant. All examples (ZBCP + PESA) easily exceeded 720 hours (one month) of continuous operation, with no significant change in pressure drop during this period, demonstrating excellent operational stability. This confirms that there is a synergistic scale inhibition effect between the ZBCP polymer structure and PESA, jointly ensuring the long-term stable operation of the system.

[0044] In summary, this invention, by combining a novel zinc-centered biomimetic catalytic polymer (ZBCP) with a gradient absorption dual-cycle coupling process, not only fundamentally solves the core problems of secondary CO2 release and slow absorption kinetics, significantly improving desulfurization and decarbonization efficiency, but also achieves unexpected technical effects of suppressing ammonia escape and preventing system scaling through ingenious component and process design. This provides an efficient, stable, and economically feasible solution for the industrial application of integrated ammonia-based desulfurization and decarbonization technology.

[0045] It should be noted that, in this document, terms such as “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0046] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An integrated ammonia-based desulfurization and decarbonization process, characterized in that, Includes the following steps: S1. Dust removal is performed on the flue gas containing sulfur dioxide and carbon dioxide, and then it is sent into the cooling tower. The temperature of the flue gas is reduced to 35-45°C by spraying cooling water to obtain pretreated flue gas. S2. Dissolve the zinc-centered biomimetic catalytic polymer and the scale inhibitor / dispersant in ammonia water to obtain a biomimetic catalytic absorbent; the ammonia water has a mass fraction of 15%–20%. S3. The pretreated flue gas is fed into an integrated absorption tower, which is divided into a desulfurization section and a decarbonization section from bottom to top. In the decarbonization section, the biomimetic catalytic absorbent prepared in step S2 is brought into countercurrent contact with the flue gas to absorb carbon dioxide in the flue gas and generate carbon-rich absorbent. In the desulfurization section, the carbon-rich absorbent flowing down from the decarbonization section is used as a desulfurizing agent to react with sulfur dioxide in the newly entered pretreated flue gas to generate sulfite slurry and release secondary flue gas containing carbon dioxide. The secondary flue gas is guided to the lower part of the decarbonization section through the internal flow guide structure of the tower for secondary decarbonization treatment; S4. The sulfite slurry at the bottom of the desulfurization section is sent into the oxidation tank, and air is introduced for oxidation to generate ammonium sulfate solution. Then, after evaporation, concentration, cooling and crystallization, centrifugation and drying, ammonium sulfate crystal product is obtained. S5. The purified flue gas at the top of the decarbonization section is discharged after being washed with water to remove ammonia. The carbon-rich absorbent is diverted to the regeneration tower, where high-purity carbon dioxide is released through heating and desorption for collection and utilization. The desorbed lean liquid is returned to step S2 for recycling.

2. The integrated ammonia-based desulfurization and decarbonization process according to claim 1, characterized in that, The zinc-centered biomimetic catalytic polymer was prepared by the following steps: Step 1: Dissolve polyethyleneimine in anhydrous ethanol to form a PEI-ethanol solution; Step 2: Add 2-amino-2-methyl-1-propanol dropwise to the PEI-ethanol solution and heat at 60°C for 4-6 hours to obtain an AMP-functionalized polyethyleneimine solution; Step 3: Add the ethanol solution of zinc acetate dropwise to the AMP-functionalized polyethyleneimine solution, and stir the reaction at 40-60°C for 2 hours. After the reaction is completed, the reaction product is obtained. Step 4: Remove the solvent from the reaction product by vacuum distillation, then dialyze with water and freeze dry to obtain the zinc-centered biomimetic catalytic polymer.

3. The integrated ammonia-based desulfurization and decarbonization process according to claim 2, characterized in that, The mass fractions of the raw materials used in steps one, two, and three are as follows: 100 parts polyethyleneimine, 600 parts anhydrous ethanol, 20 parts 2-amino-2-methyl-1-propanol, and 10 parts zinc acetate.

4. The integrated ammonia-based desulfurization and decarbonization process according to claim 2, characterized in that, The molecular weight of the polyethyleneimine is 10,000 to 25,000 g / mol.

5. The integrated ammonia-based desulfurization and decarbonization process according to claim 1, characterized in that, The scale inhibitor and dispersant is polyepoxysuccinic acid.

6. The integrated ammonia-based desulfurization and decarbonization process according to claim 1, characterized in that, In step S2, based on the total mass of the ammonia solution, the amount of zinc-centered biomimetic catalytic polymer added is 0.5 to 2.0 wt%, and the amount of scale inhibitor and dispersant added is 0.05 to 0.2 wt%.

7. The integrated ammonia-based desulfurization and decarbonization process according to claim 1, characterized in that, In step S4, the oxidation temperature of the oxidation tank is 50-55℃.

8. The integrated ammonia-based desulfurization and decarbonization process according to claim 1, characterized in that, In step S5, the desorption temperature of the regeneration tower is 95–100°C.

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