CO2 absorption and purification anti-degradation trace additive based on morpholine derivative

Abstract

The invention provides an anti-degradation trace additive based on morpholine derivatives, and aims to solve the long-standing problems of solvent degradation and equipment corrosion in the CO2 trapping process. The anti-degradation trace additive is composed of 40-65 wt% of a specific morpholine derivative, 5-15 wt% of a nonionic surfactant and 5-20 wt% of a water-soluble high-molecular polymer, and has a ternary system intermolecular synergistic effect. The degradation-resistant trace additive based on the morpholine derivative is added into a main solvent or mixed with the main solvent to prepare a compound solution, the problems of degradation and corrosion in amino CO2 capture can be solved (the degradation rate of the main solvent is inhibited to be 0.8% or below, and the corrosion rate to carbon steel equipment is remarkably reduced to be 0.038 mm / year or below), and energy consumption is further reduced. The invention provides a scheme of a morpholine derivative anti-degradation trace additive for overcoming solvent degradation and equipment corrosion for a CO2 capture technology, and has a great application prospect in the field of CO2 capture.

Description

Technical Field

[0001] This invention belongs to the field of CO2 capture technology, specifically, it relates to an anti-degradation trace additive based on morpholine derivatives and its application in CO2 capture by chemical absorption method. Background Technology

[0002] Since the Industrial Revolution, the large-scale use of fossil fuels has led to a continuous rise in global carbon dioxide emissions, exacerbating the greenhouse effect and making climate change an increasingly serious problem. Among numerous carbon reduction technologies, post-combustion carbon dioxide capture is one of the key pathways, and amine-based chemical absorption is considered the process with the greatest industrialization potential due to its mature technology and wide applicability. However, in the process of moving from the laboratory to large-scale industrial application, this technology has always faced the problems of solvent chemical degradation and system equipment corrosion. In a typical post-combustion flue gas environment, amine solvents come into contact with residual oxygen, carbon dioxide, and trace amounts of impurities such as sulfur dioxide and nitrogen oxides in the absorption tower. Under the catalysis of metal ions, complex oxidative degradation reactions occur. This process not only irreversibly consumes the effective amine components, leading to a decrease in absorption capacity and rate, but also requires continuous replenishment of expensive fresh solvents, directly increasing operating costs. More seriously, the acidic products such as formic acid and acetic acid produced by oxidative degradation drastically lower the system pH value, causing severe corrosion to process equipment, which is mainly made of carbon steel. The Fe released during the corrosion process... 2+ / Fe 3+ Metal ions can further catalyze oxidative degradation reactions, thus forming a vicious cycle of degradation and corrosion that is difficult to stop. These two major problems severely restrict the economy, stability, and long-term operational reliability of the amine-based carbon capture process.

[0003] In the existing technology, the following solutions are mainly adopted to solve the above problems: First, the process optimization route, such as reducing the oxidation risk through process improvement such as air stripping deoxygenation (CN119857342A), but this method often increases the system complexity and energy consumption; Second, the chemical additive route, such as adding antioxidants, corrosion inhibitors, etc. to the absorbent (such as the amine protective agent composition disclosed in CN113831543A), but these additives are mostly passive defenses with limited effects and may introduce new balance problems; Third, the development of new absorbent systems, such as the ionic liquid-amine complex system (CN115160256A), but these new technologies are often constrained by high costs and insufficient technological maturity.

[0004] Through in-depth research into the degradation mechanism of monoethanolamine (MEA) and other alcoholic amine solvents, the inventors discovered that MEA generates various nitrogen-containing heterocyclic compounds during oxidative degradation. Among these, the morpholine ring structure, as an important degradation product, exhibits unexpected chemical stability. This discovery provides us with an important research direction: since the morpholine structure can exist stably in harsh oxidative environments, could it be utilized as an antioxidant component to develop anti-degradation trace additives based on morpholine derivatives to protect the main solvent from degradation? Furthermore, there are precedents in the prior art for using morpholine / piperazine derivatives for CO2 capture, but their technical approaches are fundamentally different from those of this invention. For example, CN103221125A discloses the use of complex morpholine / piperazine derivatives as the main absorbent, improving CO2 absorption performance through their unique spatial structure; CN105396447A and CN105413396A use morpholine compounds as the main component in a composite system, aiming to optimize absorption capacity and rate through molecular design. While these technical solutions have improved absorption performance to some extent, they all position morpholine derivatives as the main functional components, with a high addition ratio (usually exceeding 10%), and have failed to effectively solve the equipment corrosion problem caused by degradation products.

[0005] Therefore, the inventors have developed a multifunctional anti-degradation trace additive based on morpholine derivatives. This additive utilizes the inherent chemical stability of the morpholine ring to form a protective layer at the molecular level, effectively blocking the attack of oxygen and free radicals on the main solvent; simultaneously, it fundamentally breaks the vicious cycle of "degradation-corrosion" by inhibiting the formation of acidic degradation products. Compared with existing technologies, this invention achieves a technological shift from "participating in the reaction" to "protecting the reaction," providing a novel solution to the problems of solvent chemical degradation and system equipment corrosion in the amine-based carbon capture process. Summary of the Invention

[0006] Based on the inventor's previously filed invention patent "2025114089771", the inventor unexpectedly discovered that by replacing the organic alkanolamine with a morpholine derivative as the core component, a ternary system can be constructed. This system consists of a morpholine derivative with a specific structure as a trace synergistic center (0.1-5 wt%), a specific nonionic surfactant, and a water-soluble polymer. Through precise control of physical parameters, a significant synergistic effect can be achieved. This system primarily functions at the molecular, interfacial, and bulk scales. By controlling the interfacial tension, proton transfer efficiency, and bulk stability of the solution, it simultaneously achieves anti-degradation and anti-corrosion properties, which were previously considered difficult to achieve simultaneously. Specifically, the morpholine derivative anti-degradation trace additive suppresses the degradation rate of the main solvent to below 0.8%, significantly reduces the corrosion rate of carbon steel equipment to below 0.038 mm / year, and further reduces energy consumption.

[0007] The technical solution of this invention is to provide an anti-degradation trace additive based on morpholine derivatives, the specific technical solution of which is as follows:

[0008] This invention provides a trace anti-degradation additive based on morpholine derivatives, the composition of which, by weight percentage, comprises:

[0009] (1) At least one morpholine compound, ranging from 40 wt% to 65 wt%;

[0010] (2) At least one nonionic surfactant, ranging from 5 wt% to 15 wt%;

[0011] (3) 5 wt% to 20 wt% of at least one water-soluble polymer;

[0012] The remainder is water.

[0013] Preferably, at least one of the following: morpholine, N-methylmorpholine, N-ethylmorpholine, N-(3-aminopropyl)morpholine, and (2) N-(2-ethoxyethyl)-3-morpholinopropyl-1-amine (EEMPA).

[0014] Preferably, the nonionic surfactant (hydrophilic-lipophilic balance (HLB) of 4.0 to 16.0) is a sorbitan fatty acid ester (Span-80) or a polyoxyethylene sorbitan fatty acid ester (Tween-80).

[0015] Preferably, the water-soluble polymer is selected from at least one of polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyethylene glycol, or polyacrylamide.

[0016] Preferably, the morpholine derivatives are used to synergistically optimize the absorption rate, anti-degradation performance, and regeneration efficiency of the system by adjusting their types and proportions;

[0017] Preferably, the nonionic surfactant has an HLB value of 4.3-15.0 at 25 °C to adapt to the polarity requirements of different main solvent systems;

[0018] Preferably, the molecular weight of the polymer is 30,000-70,000 g / mol to ensure its appropriate solubility and thickening effect in water;

[0019] Preferably, the anti-degradation trace additive based on morpholine derivatives can form a homogeneous solution with the main solvent and water through simple mechanical stirring, without the need for special equipment;

[0020] Preferably, the anti-degradation trace additive based on morpholine derivatives is suitable for both continuous and intermittent industrial operation modes;

[0021] Preferably, the mass ratio of the morpholine derivative-based anti-degradation trace additive in the compound absorbent is 0.1-5 wt%. This ratio, after systematic optimization, can control costs to the maximum extent while ensuring activity.

[0022] More preferably, the anti-degradation trace additive of the morpholine derivative is compounded with the main solvent to form an absorbent, wherein the main solvent is selected from at least one of monoethanolamine, diethanolamine, N-methyldiethanolamine, piperazine, amino acid salt or ionic liquid, the concentration of the main solvent is 15-55 wt%, the concentration of the trace additive is 0.1-5 wt%, and the balance is water.

[0023] The method for preparing the morpholine derivative anti-degradation trace additive of the present invention is characterized by comprising the following steps:

[0024] (a) In a reaction vessel, the water-soluble polymer is slowly added to water under stirring to prepare a 3-5 wt% pre-swollen solution;

[0025] (b) Mix the morpholine derivative with the pre-swollen solution obtained in step (a) and stir at 200-300 rpm for 20-30 minutes;

[0026] (c) Slowly add the nonionic surfactant and increase the speed to 400-500 rpm, and continue stirring for 1-1.5 hours until a homogeneous and transparent solution is obtained, which is the trace additive.

[0027] The method of using the anti-degradation trace additive of the morpholine derivative of the present invention is characterized in that the trace additive is added to the main solvent or mixed with the main solvent to prepare a compound solution, and the anti-degradation and anti-corrosion performance is optimized by adjusting its molar ratio, and energy consumption is further reduced. It is suitable for both continuous replenishment and intermittent addition industrial operation modes.

[0028] The working principle of the morpholine derivative anti-degradation trace additive of the present invention is as follows:

[0029] Based on a multi-scale synergistic mechanism, this invention achieves a systematic breakthrough in CO2 capture performance through precise regulation and synergistic effects at the molecular, interface, and bulk levels. At the molecular level, morpholine derivatives with specific structures play three key roles. First, their unique cyclic structure forms an effective "molecular shield" around the main solvent molecule through steric hindrance, significantly blocking free radical attacks on the amine active sites. This mechanism reduces solvent degradation and extends solvent lifespan. Second, the nitrogen atom on the morpholine ring acts as a highly efficient proton relay station, constructing a rapid proton transfer channel, thereby increasing the CO2 absorption rate. Furthermore, the alkyl / ether hydrophobic chain introduced by specific morpholine derivatives significantly lowers the activation energy barrier for CO2 desorption by weakening the solvation of CO2 carriers and water molecules, thus reducing regeneration energy consumption and achieving significant energy savings.

[0030] In terms of interface scale control, nonionic surfactants and morpholine derivatives exhibit a remarkable synergistic effect at the gas-liquid interface. The dense composite interfacial film formed by the two reduces the oxygen mass transfer coefficient and the oxidative degradation rate, effectively blocking the oxidative degradation pathway at the source of mass transfer while maintaining normal CO2 absorption and mass transfer. This composite film also significantly reduces the surface tension of the solution, promoting the coalescence and escape of CO2 bubbles during regeneration, thereby increasing the CO2 desorption rate, improving the processing capacity of the regeneration tower, and reducing equipment investment costs. More importantly, the foam control mechanism of this system reduces the height of foam generated during absorption, greatly improving the stability and operational flexibility of the unit.

[0031] At the bulk scale, the weak three-dimensional network structure built by the water-soluble polymer through its long molecular chains effectively eliminates concentration and temperature gradients in the solution, significantly reducing the corrosion rate of carbon steel and extending the equipment's service life by more than double. This network structure also ensures the uniform dispersion of each functional component in the system, guaranteeing continuous performance stability during long-term operation. Simultaneously, through precise viscosity control, the system reduces solution viscosity, effectively suppressing turbulence while maintaining good flowability and mass transfer characteristics, achieving an optimal balance between mass transfer efficiency and operating energy consumption.

[0032] The synergistic effect of these three scales forms a complete performance optimization system, namely, the chemical function regulation at the molecular scale, the mass transfer process optimization at the interface scale, and the construction of a stable environment at the bulk scale. These three scales work together to solve the long-standing problems of degradation, corrosion, and long-term stability in the amine-based CO2 capture process, providing a brand-new solution for the industrial application of amine-based CO2 capture technology.

[0033] This invention also includes the application of morpholine derivative anti-degradation trace additives. This compound system is used for CO2 capture of industrial flue gas from coal-fired power plants, steel plants, etc. The specific steps are as follows:

[0034] (a) Under conditions of 35-45 °C, the CO2-containing flue gas is subjected to a countercurrent contact with the compound absorbent in the absorption tower for absorption reaction;

[0035] (b) The CO2-enriched absorbent solution is thermally regenerated at 70-140 °C and normal pressure to obtain CO2 gas with a purity of not less than 99.5%.

[0036] Compared with the prior art, the core advantages of this invention are reflected in the following aspects:

[0037] (1) Breakthrough improvement in anti-degradation performance. Based on the unique "physical property regulation" pathway, this invention utilizes the steric hindrance effect generated by the cyclic structure of the morpholine derivative to form an effective "molecular shield" around the main solvent molecule, significantly blocking free radical attacks. Experimental data show that after 1000 hours of accelerated cycling testing, the degradation rate of the MEA system containing the additives of this invention is only 1.0-1.5%, far lower than the more than 15% of the traditional MEA system, thus extending the solvent lifespan.

[0038] (2) Significantly reduced regeneration energy consumption. This invention achieves a breakthrough in energy consumption in multiple aspects through the synergistic effect of the ternary system: the hydrophobic microenvironment constructed by specific morpholine derivatives weakens the solvation effect between CO2 carriers and water molecules, significantly reducing the activation energy barrier for CO2 desorption; at the same time, the effective regulation of interfacial tension promotes the coalescence and escape of CO2 bubbles, increasing the regeneration rate by 30-173%. Under the combined effect, the regeneration energy consumption is reduced from ~4.0 GJ / t CO2 of traditional MEA to ≤2.2 GJ / t CO2, a reduction of more than 45%.

[0039] (3) Significantly improved equipment corrosion resistance. The weakly basic properties of morpholine derivatives combined with the three-dimensional network structure constructed by water-soluble polymers effectively eliminate the concentration and temperature gradients in the solution, significantly reducing the corrosion rate of carbon steel from >0.1 mm / year in the traditional system to <0.05 mm / year, extending the service life of equipment by more than double and greatly reducing equipment maintenance costs.

[0040] (4) Excellent industrial applicability. The additive of this invention is in trace liquid form, with an addition amount of only 0.1-5 wt%, which can be directly added to existing amine capture systems without modifying core equipment such as absorption towers, heat exchangers, and pumps, achieving a "plug-and-play" upgrade. It shows good compatibility with mainstream main solvents such as MEA, MDEA, and piperazine, without stratification or precipitation, and is suitable for various industrial scenarios such as coal-fired power plants and steel plants.

[0041] (5) Synergistic optimization of absorption and regeneration performance. This invention successfully solves the technical contradiction of "absorption rate and regeneration energy consumption" that is difficult to balance in traditional technology: the nitrogen atom in the morpholine derivative acts as a highly efficient proton relay station, increasing the absorption rate by 23 wt%; while its cyclic structure and hydrophobic chain promote CO2 release during regeneration, achieving a 173% increase in regeneration rate, and ultimately significantly reducing regeneration energy consumption while maintaining high absorption efficiency.

[0042] (6) Excellent environmental friendliness and economic efficiency. All components are environmentally friendly substances and do not contain restricted chemicals such as heavy metals and fluorides. The characteristic of adding in trace amounts makes the additive low in cost and short in investment payback period, with significant economic and environmental benefits. Detailed Implementation

[0043] The performance indicators were tested using the following methods:

[0044] The 1000-hour degradation rate test method assesses the chemical stability of the amine component in the absorbent through accelerated degradation experiments. The specific steps are as follows: First, 500 mL of the absorbent sample to be tested is placed in a closed degradation reactor and continuously circulated for 1000 hours under simulated flue gas conditions (CO2 concentration 15%, temperature 40±1 ℃), allowing the absorbent to circulate between the absorption and regeneration units. During this period, samples are taken every 100 hours, and the concentration of MEA (monoethanolamine) in the sample is determined by acid-base titration (using 0.1 M HCl standard solution and methyl orange indicator). Finally, the degradation rate is calculated as the percentage of the difference between the initial MEA concentration and the MEA concentration at 1000 hours relative to the initial concentration, using the formula: Degradation rate (wt%) = [(Initial MEA concentration - MEA concentration at 1000 hours) / Initial MEA concentration] × 100%.

[0045] The absorption / regeneration rate was determined using a custom-designed bubbling absorption apparatus (gas-liquid contact volume 1L). 500mL of the compounded solvent was placed in the apparatus, and a constant temperature was maintained (40℃ for absorption, 80℃ for regeneration). Simulated flue gas (a CO2 / N2 mixture, CO2 volume fraction 15%) was introduced at a constant flow rate of 300 mL / min. The CO2 concentration in the outlet gas was monitored using an online infrared CO2 analyzer. The CO2 absorption / desorption rate per unit time and unit volume of liquid was calculated based on material balance, thus yielding the rate.

[0046] The absorption capacity / poor solution load is calculated by taking an appropriate amount of rich solution after absorption reaches saturation and determining the CO2 load using the standard hydrochloric acid titration method.

[0047] The regeneration energy consumption was measured by placing the regeneration process in a round-bottom flask equipped with a reflux condenser and heating it in an oil bath. The electrical energy consumed in maintaining the regeneration temperature (80 °C) until desorption was complete was monitored by a power meter, and the unit energy consumption (GJ / t CO2) was calculated based on the mass of desorbed CO2.

[0048] The regeneration efficiency DP value is calculated using the formula DP = average desorption rate × circulation capacity.

[0049] The corrosion rate was measured using the strip loss method (ASTM G1 standard), where 20# carbon steel strips (28 cm² surface area) were used. 2 After immersion in a lean solution at 80 °C for 720 hours, the average corrosion rate was calculated.

[0050] The foam height was measured by adding 250 mL of lean solution at 40 °C to a 500 mL graduated cylinder, and then blowing N2 from the bottom at a rate of 200 mL / min for 5 minutes. After turning off the gas source, the foam height was recorded after stabilization.

[0051] The 100-cycle retention rate test method assesses the long-term stability of the absorbent performance through multiple forced cycles. Using a circulation device, the absorbent sample undergoes 100 consecutive absorption-regeneration cycles; each cycle includes absorption for 30 minutes at 40±1℃ (simulating a flue gas CO2 concentration of 15t%), followed by regeneration for 30 minutes at 100±2℃ and atmospheric pressure. At the beginning of the cycle (1st cycle) and at the end of the cycle (100th cycle), samples are taken to determine the CO2 absorption capacity of the absorbent (using the same method as the cycle capacity test). The 100-cycle retention rate is calculated as the percentage of the absorption capacity in the 100th cycle to the absorption capacity in the 1st cycle, using the formula: Retention rate (%) = [Absorption capacity in the 100th cycle / Absorption capacity in the 1st cycle] × 100%.

[0052] Example 1: Preparation of core additives

[0053] A morpholine-based anti-degradation trace additive, comprising the following components by weight percentage: 62.5 wt% N-ethylmorpholine, 7.5 wt% polyvinylpyrrolidone (PVP, K30, molecular weight 58000±5000), 12.5 wt% Span-80 (HLB=4.3), and 17.5 wt% water.

[0054] Preparation method: In a 500 mL reactor, 7.5 g of PVP was slowly added to 17.5 g of deionized water under low-speed stirring (150 rpm), controlling the addition rate to prepare a pre-swelling solution. The solution was allowed to swell for 30 minutes until completely transparent. Then, 62.5 g of N-ethylmorpholine (purity ≥99 wt%) was added, and the mixture was stirred at 250 rpm for 25 minutes. Finally, 12.5 g of Span-80 was slowly added, and the stirring speed was increased to 450 rpm, with continuous stirring for 1.5 hours to obtain a homogeneous and transparent trace additive A. The product had a solid content of 40.2 wt%, a pH of 9.2 (25 ℃), and a viscosity of 185 cP (25 ℃).

[0055] Example 2: Preparation of additives with different morpholine derivatives

[0056] Prepared according to the method of Example 1 and the same weight percentage system:

[0057] Additive B: Composed of the following components by weight percentage: N-ethylmorpholine 37.5 wt%, EEMPA 25 wt%, PVP 7.5 wt%, Span-80 11.25 wt%, and water 18.75 wt%.

[0058] Additive C: Composed of the following components by weight percentage: N-methylmorpholine 43.75 wt%, PVP 6.25 wt%, Tween-80 (HLB=15.0) 9.375 wt%, water 40.625 wt%.

[0059] Additive D: Composed of the following components by weight percentage: N-ethylmorpholine 40.65 wt%, PVP 5 wt%, Span-80 7.5 wt%, water 46.875 wt%.

[0060] Example 3: Verification of Additive Dosage Range

[0061] Additive A prepared in Example 1 was added to a 30 wt% MEA aqueous solution at different concentrations: 0.1 wt%, 0.5 wt%, 2.0 wt%, and 5.0 wt%, and its performance under standard conditions was tested.

[0062] Example 4: Core Performance Testing of Compound Absorbent

[0063] The above additives were compounded at a dosage of 2 wt% with 30 wt% MEA aqueous solution and evaluated in a standard testing apparatus. Test conditions: absorption temperature 40 ± 1 ℃, simulated flue gas CO2 concentration 15%; regeneration temperature 80 ± 2 ℃, atmospheric pressure. Each sample was tested in triplicate, and the average value was taken.

[0064] Comparative Example 1: Traditional MEA System

[0065] 30 wt% MEA aqueous solution, without any added functional additives.

[0066] Comparative Example 2: Existing technology (chemical regulation) system.

[0067] Referring to the applicant's prior patent, an additive containing 5 wt% sodium citrate and 2 wt% sodium dodecylbenzenesulfonate was added to 30 wt% MEA at 2 wt%.

[0068] Comparative Example 3: Single Morpholine Additive System

[0069] Add only 2 wt% N-ethylmorpholine to 30 wt% MEA.

[0070] Comparative Example 4: System lacking surfactant

[0071] In a 30 wt% aqueous MEA solution, 2 wt% of a premix lacking surfactant was added. The premix consisted of 62.5 wt% N-ethylmorpholine, 7.5 wt% PVP, and 30 wt% water.

[0072] Comparative Example 5: Deficit Polymer System

[0073] In a 30 wt% aqueous MEA solution, 2 wt% of a premix of a missing polymer was added, which consisted of 62.5 wt% N-ethylmorpholine, 12.5 wt% Span-80, and 25 wt% water.

[0074] Comparative Example 6: Incorrect Technical Path System

[0075] In a 30 wt% aqueous MEA solution, 2 wt% of a faulty path premix was added, which consisted of 62.5 wt% N-ethylmorpholine, 12.5 wt% sodium dodecylbenzenesulfonate (anionic surfactant), 7.5 wt% PVP, and 17.5 wt% water.

[0076] Table 1 Performance test results of the examples and comparative examples

[0077] Test Project Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Example 3-A Example 3-B Example 3-C Degradation rate (%) after 1000 hours 15.2 2.5 4.8 5.2 3.1 2.8 0.4 0.6 0.78 <![CDATA[Regeneration energy consumption (GJ / t CO2)]]> 4.04 3.45 3.62 3.58 3.72 3.51 2.18 2.05 2.35 Corrosion rate (mm / year) 0.125 0.085 0.098 0.102 0.089 0.091 0.038 0.032 0.045 <![CDATA[Average absorption rate (10 -5 mol / (L·s))]]> 49.38 51.24 53.67 52.89 50.12 52.45 68.45 72.16 62.38 <![CDATA[Maximum regeneration rate (10⁻ 5 mol / (L·s))]]> 77.4 92.15 105.32 98.76 88.45 95.67 245.68 268.94 198.76 Cyclic capacity (mol / L) 0.691 0.785 0.823 0.798 0.765 0.812 1.486 1.523 1.327 Foam height (cm) 32.5 28.7 35.2 38.5 30.2 25.4 4.2 3.8 5.6 Retention rate after 100 cycles (wt%) 62.5 78.3 72.8 75.6 87.2 79.5 96.8 97.5 94.3

[0078] Performance testing with different additive dosages

[0079] Test method: Additive A prepared in Example 1 was added to a 30 wt% MEA aqueous solution at five concentration gradients: 0.1 wt%, 0.5 wt%, 1.0 wt%, 2.0 wt%, and 5.0 wt%, respectively, and the performance was evaluated under standard test conditions.

[0080] Table 2 Performance of different additive dosages

[0081] Test Project Comparative Example 1 (0 wt%) Add 0.1 wt% Add 0.5 wt% Add 1.0 wt% Add 2.0 wt% Add 5.0 wt% 1000-hour degradation rate (wt%) 15.2 2.1 1.2 0.9 0.8 0.7 Regeneration energy consumption (GJ / t CO2) 4.04 3.50 2.80 2.45 2.18 2.15 Corrosion rate (mm / year) 0.125 0.068 0.045 0.041 0.038 0.036 <![CDATA[Average absorption rate (10⁻ 5 mol / (L·s))]]> 49.38 55.23 62.15 65.78 68.45 69.12 <![CDATA[Maximum regeneration rate (10⁻ 5 mol / (L·s))]]> 77.4 125.36 198.45 230.15 245.68 248.92 Cyclic capacity (mol / L) 0.691 0.895 1.235 1.386 1.486 1.502 Foam height (cm) 32.5 15.6 8.2 5.8 4.2 3.9 Retention rate after 100 cycles (wt%) 62.5 82.3 90.5 94.2 96.8 97.1

[0082] Experimental Results and Comparative Analysis

[0083] To demonstrate the inventiveness and non-obviousness of this invention, we designed a systematic comparative experiment (see Table 1 for details). The results fully demonstrate that the technical effects of this invention far exceed what can be expected from the simple summation of prior art.

[0084] (1) This invention vs. prior patent (Comparative Example 2: Chemical regulation pathway)

[0085] In terms of anti-degradation, the present invention (degradation rate 0.8%) is several times better than the previous patent (degradation rate 2.5%), proving that the "physical regulation" pathway is superior to the "chemical regulation" pathway in inhibiting degradation.

[0086] Regarding regeneration energy consumption, this invention (2.18 GJ / t CO2) represents a revolutionary breakthrough compared to the previous patent (3.45 GJ / t CO2), with a reduction of over 35%. This is particularly surprising because simply replacing the main component usually makes it difficult to reduce energy consumption so significantly while maintaining degradation resistance. This demonstrates that the ternary system of this invention has a unique and unpredictable advantage in reducing the activation energy of CO2 desorption.

[0087] (2) The present invention vs. the missing component system (Comparative Examples 3-5)

[0088] Comparative Example 3 (morpholine only) demonstrated that the lack of synergy between Span-80 and PVP significantly weakened the anti-degradation and energy-saving effects.

[0089] Comparative Examples 4 (lacking surfactant) and 5 (lacking polymer) demonstrate that the absence of any component in the ternary system of this invention leads to a significant decrease in performance. This strongly demonstrates that Span-80 and PVP are not conventional auxiliaries that can be easily substituted in the art; rather, they possess a precise, functionally complementary synergistic relationship with specific morpholine derivatives.

[0090] (3) The present invention successfully resolved the technical contradiction.

[0091] Traditional view holds that increasing the absorption rate often leads to increased regeneration energy consumption, and vice versa. However, Embodiment 3-A of the present invention increases the average absorption rate by 38.6% while reducing regeneration energy consumption by 46%. This "fast and economical" effect completely breaks the technical contradiction in the field and is an unexpected technical achievement brought about by the synergistic effect of the present invention.

Claims

1. A trace additive for resisting degradation based on morpholine derivatives, characterized in that: The mixture comprises 40 wt% to 65 wt% of at least one morpholine derivative, 5 wt% to 15 wt% of at least one nonionic surfactant, 5 wt% to 20 wt% of at least one water-soluble polymer, and the balance being water.

2. The anti-degradation trace additive based on morpholine derivatives according to claim 1, characterized in that, The morpholine derivative is at least one of morpholine, N-methylmorpholine, N-ethylmorpholine, N-(3-aminopropyl)morpholine, and N-(2-ethoxyethyl)-3-morpholinopropyl-1-amine (EEMPA), the nonionic surfactant (hydrophilic-lipophilic balance (HLB) of 4.0 to 16.0) is a sorbitan fatty acid ester (Span-80) or a polyoxyethylene sorbitan fatty acid ester (Tween-80), and the water-soluble polymer is selected from at least one of polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyethylene glycol, or polyacrylamide.

3. A method for preparing the anti-degradation trace additive based on morpholine derivatives as described in claims 1-2, characterized in that, Includes the following steps: (a) In a reaction vessel, the water-soluble polymer is slowly added to water under stirring to prepare a 3-5 wt% pre-swollen solution; (b) The morpholine derivative is mixed with the pre-swollen solution obtained in step (a) and stirred at 200-300 rpm for 20-30 minutes; (c) The nonionic surfactant is slowly added and the stirring speed is increased to 400-500 rpm, and the stirring is continued for 1-1.5 hours until a homogeneous and transparent solution is obtained, which is the trace additive.

4. A method of using the anti-degradation trace additive based on morpholine derivatives as described in claims 1-3, characterized in that, It involves adding trace amounts of additives to the main solvent or mixing them with the main solvent to prepare a compound solution.

5. The anti-degradation trace additive based on morpholine derivatives according to claims 1-4, characterized in that, The morpholine derivative anti-degradation trace additive optimizes anti-degradation and anti-corrosion performance by adjusting its molar ratio, and further reduces energy consumption. It is suitable for both continuous replenishment and intermittent addition in industrial operation modes.

6. A compound absorbent comprising the anti-degradation trace additives based on morpholine derivatives as described in claims 1-5, characterized in that, It consists of the following components: 15-55 wt% main solvent, 0.1-5 wt% anti-degradation trace additive of the morpholine derivative of claim 1, and the balance being water, wherein the main solvent is selected from at least one of monoethanolamine, diethanolamine, N-methyldiethanolamine, piperazine, amino acid salt or ionic liquid.

7. The application of the compound absorbent according to claim 6 in capturing CO2 in flue gas from coal-fired power plants or steel plants, characterized in that, Includes the following steps: (a) At 35-45 °C, CO2-containing flue gas is brought into countercurrent contact with the compound absorbent in the absorption tower for absorption reaction; (b) At 70-140 °C and normal pressure, the CO2-enriched absorbent solution is thermally regenerated to obtain CO2 gas with a purity of not less than 99.5 wt%.