A method for optimizing the solid-phase properties of CO2 phase change absorbers based on crystal structure regulation.

Abstract

This invention relates to the field of carbon dioxide capture technology, addressing the technical problems of uncontrollable crystal phase structure, high product viscosity, limited solid-phase CO2 loading, and lack of quantitative control methods in existing CO2 phase change absorbers during solid-phase precipitation. Specifically, it relates to a method for optimizing the solid-phase performance of CO2 phase change absorbers based on crystal phase structure control. This method first achieves directional control of crystal phase structure parameters such as crystallinity, grain size, and microstrain in the absorber system by controlling the type and doping ratio of the crystal phase regulator. Subsequently, a quantitative structure-activity relationship (QSAR) model is constructed to identify the dominant structural factor and inversely optimize the control path. This invention achieves precise construction of low-viscosity, high-CO2-loading solid-phase products, with a solid-phase loading ratio of not less than 90%, and features a reversible closed-loop design characteristic of structure-performance-regulator, making it suitable for various scenarios such as CO2 absorption-storage-conversion.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide capture technology, and in particular to a method for optimizing the solid-phase performance of CO2 phase change absorbers based on crystal phase structure regulation. Background Technology

[0002] Carbon dioxide capture and utilization (CCUS) is a crucial intermediate link in the current energy-environment system. Among them, liquid-solid phase change absorbents have become an important research direction for overcoming the bottlenecks of traditional amine absorbents due to their combination of high CO2 enrichment capacity and low energy consumption regeneration potential. These absorbents can undergo a liquid-solid phase change during CO2 absorption, generating solid carbonates or carbamates, thereby achieving functions such as high CO2 capture, easy separation and temporary storage, and solid-phase conversion and utilization. They have gradually attracted attention in recent years.

[0003] Although several systems have been proven to possess liquid-solid phase transition properties, the engineering applications of existing absorbents remain constrained by several key bottlenecks. The core issues mainly lie in the control of the structure and properties of the solid-phase products, namely:

[0004] First, the crystal structure of the solid-phase product is uncontrollable. The phase transition process induced by CO2 absorption is usually a rapid crystallization process, and the reaction pathway is mostly limited by the steric hindrance of the absorbent molecules themselves, solvent polarity, and hydrogen bond network. The resulting solid phase often exhibits coarse grains, uneven morphology, and severe crystal structure defects, leading to adhesion and aggregation between solid phases, poor macroscopic rheological properties of the system, and difficulties in pumping and regeneration.

[0005] Secondly, the solid-phase CO2 enrichment capacity is limited. Due to the lack of design and control of the crystal phase structure, the distribution of reaction sites inside the solid phase is loose, and the CO2 absorption products are unevenly distributed between the liquid and solid phases. The actual solid phase load is often insufficient to support the "solid-dominant" enrichment mode, making it difficult to fully release the application advantages of phase change absorbers.

[0006] Secondly, there is a lack of effective structure-property correlation mechanisms. Currently, absorbent design mainly relies on empirical rules or single-factor regulation, making it impossible to predict key properties such as the solid-phase CO2 loading and system viscosity based on crystal phase structure parameters. Although crystal phase information such as grain size, crystallinity, microstrain, and principal crystal plane structure has been extensively studied in the materials science field, a quantitative correlation model has not yet been established in the CO2 liquid-solid phase transition system, limiting the scientific rigor of regulator design and the predictability of absorbent performance.

[0007] To address these challenges, some studies have attempted to introduce sterically hindered amines, polar solvents, or auxiliaries to regulate crystal nucleation and growth behavior, or to adjust crystallization kinetics using different operating conditions. However, the following limitations still exist: First, the regulation lacks parameterized model support, and the causal relationship between crystal phase evolution path and product performance is unclear. Second, the screening process for regulators still relies on trial and error, lacking a structure-activity relationship mechanism. Third, the evaluation system remains focused on apparent indicators (such as apparent phase change, initial loading, etc.), with insufficient understanding of the transmission mechanism between microscopic crystal structure and macroscopic properties.

[0008] In summary, current research on liquid-solid phase change CO2 absorbents urgently needs to start from the microscopic crystal structure, establish a quantitative structure-property relationship model, and combine machine learning methods to realize a three-dimensional closed-loop design system for crystal phase regulation, performance optimization, and regulator screening. This would fundamentally overcome the problems of unclear structure, unpredictable performance, and unclear regulation path in absorbent design, and improve the engineering practicality and material innovation capabilities of absorbents. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides a method for optimizing the solid-phase performance of CO2 phase change absorbers based on crystal phase structure regulation. This method solves the technical problems of uncontrollable crystal phase structure, high product viscosity, limited solid-phase CO2 loading, and lack of quantitative regulation methods in existing CO2 phase change absorbers during solid-phase precipitation.

[0010] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for optimizing the solid-phase performance of CO2 phase change absorbers based on crystal phase structure regulation, the method comprising the following steps:

[0011] An absorbent system capable of undergoing a liquid-solid phase transition and precipitating solid products during carbon dioxide absorption is selected. The absorbent system contains at least one basic component that can react with CO2 to form a carbamate or carbonate solid phase. By doping with crystal phase modifiers possessing hydrogen bonding control capabilities or steric hindrance effects (such as 2-methylaminoethanol, 2-amino-2-methyl-1-propanol, etc.), a specific crystal structure is induced in the solid products during absorption.

[0012] A crystal phase regulator is introduced into the absorbent system to induce the solid-phase product to form a crystalline structure during CO2 absorption. This invention explicitly proposes several key crystal phase structure parameters and their control ranges, including but not limited to: crystallinity. (30%–60%), grain size D (200–500 nm), lattice microstrain (≥0.003), main peak shift Increase in full width at half maximum (FWHM) (≥10%), lattice defect density (≥1.5×10) 14 cm-2 D 90 Particle size (≤600nm) and dominant crystal plane migration characteristics, etc. Preferably, the solid-phase product possesses an unstable low-symmetry structure, exhibiting low viscosity (≤100mmPa·s) and high CO2 loading capacity, and the solid-phase CO2 loading... It accounts for no less than 90% of the total CO2 load.

[0013] Based on experimental data from the crystal structure formation process, a quantitative structure-property relationship model was established to characterize the nonlinear functional relationship between crystal structure parameters and solid-state performance indicators. These solid-state performance indicators include the solid-state CO2 loading. and system viscosity .

[0014] Based on a quantitative structure-activity relationship (QSAR) model, this invention utilizes feature importance analysis to identify dominant structural factors among crystal phase structure parameters. These factors guide the selection and proportion adjustment of crystal phase regulators, enabling targeted regulation of low-viscosity, high-CO2-loading solid-phase products. To systematically reveal the structure-activity relationship (i.e., nonlinear functional relationship) between crystal phase structure and solid-phase performance indicators, this invention further constructs a nonlinear modeling framework based on random forest regression (RFR) and introduces the SHAP (Shapley Additive Explanations) algorithm to analyze the contribution of each crystal phase structure parameter to the target performance. The modeling input feature vector... Including crystallinity Grain size lattice microstrain Lattice defect density Main peak offset and particle size distribution standard deviation Output feature vector Solid phase CO2 loading With system viscosity The quantitative structure-activity relationship model was trained using 5-fold cross-validation, and the results showed that crystallinity... With grain size It is the most critical influencing factor, namely the dominant structural factor.

[0015] By defining target crystal phase structure characteristics and employing a multi-objective optimization algorithm in conjunction with a database of crystal phase regulators, this invention selects the types and doping ratios of crystal phase regulators that satisfy the target crystal phase structure characteristics. Based on the quantitative structure-activity relationship (QSAR) model, this invention proposes a reverse optimization screening strategy for crystal phase structure parameters. This involves defining target crystal phase structure characteristics, such as… =60~80nm, With a doping ratio of 65%–80%, and combining a crystal phase modifier database with Bayesian optimization or grid search algorithms, combinations of crystal phase modifiers with high modulation efficiency and small viscosity increase are selected. Finally, the model prediction results are validated against the modulation experimental results in a closed loop, realizing a three-dimensional collaborative design framework of crystal phase structure-performance-crystal phase modifier.

[0016] Furthermore, the crystal phase regulator includes one or more of the following categories:

[0017] Small organic molecules containing hydroxyl or amino groups;

[0018] sterically hindered amine compounds;

[0019] Polar solvents or auxiliaries that can form stable hydrogen bonds or ion pairs with the absorption products.

[0020] Furthermore, the crystal structure parameters are quantitatively characterized using one or more material structure analysis methods, including but not limited to:

[0021] X-ray diffraction (XRD) is used to determine crystallinity, full width at half maximum (FWHM) of the main peak, and grain size.

[0022] The Williamson-Hall method is used to evaluate lattice microstrain.

[0023] Infrared spectroscopy or Raman spectroscopy is used to analyze the configuration of functional groups and defect characteristics inside crystals;

[0024] Scanning or transmission electron microscopy is used to observe crystal morphology and particle distribution.

[0025] Differential scanning calorimetry is used to determine the thermal stability and recrystallization behavior of crystalline phases.

[0026] Furthermore, the nonlinear functional relationship between the crystal structure parameters and solid-state performance indicators is predicted and analyzed through machine learning modeling, the method comprising:

[0027] Constructing input feature vectors ,in, Crystallinity; The grain size is calculated using the Scherrer formula; The lattice microstrain was estimated using the Williamson-Hall method; The lattice defect density is obtained by counting from TEM images; This is the main peak offset; Standard deviation of particle size distribution in SEM images;

[0028] Constructing the output feature vector ,in, The loading of CO2 in the solid phase (mol / mol); The viscosity of the solid system is expressed in mPa·s.

[0029] A random forest regression model is used to process the input feature vector. With output feature vector A quantitative structure-property relationship model is established to model the mapping relationship between crystal phase structure parameters and solid-state properties, representing the nonlinear functional relationship between these parameters. The expression is as follows: ;

[0030] Based on the results of the quantitative structure-activity relationship model, the SHAP interpretation algorithm was used to identify crystallinity and other properties. Grain size The dominant structural factor is used to guide the selection and proportion adjustment of phase regulators to achieve directional control of low viscosity, high CO2 loading solid products.

[0031] Furthermore, the evolution path of the crystal phase structure is adjusted by the crystal phase regulator so that the crystal phase structure of the obtained solid product satisfies at least four of the following quantitative structural characteristics:

[0032] Crystallinity measured by X-ray diffraction Keep it between 30% and 60%;

[0033] Average grain size The wavelength is 200–500 nm, and D 90 Particle size not exceeding 600 nm;

[0034] Lattice defect density Not less than 1.5×10 14 cm -2 ;

[0035] The crystal structure exhibits a low symmetry, accompanied by an increase of ≥10% in the full width at half maximum (FWHM) of the main XRD peak;

[0036] Lattice microstrain The value is not less than 0.003;

[0037] The characteristic crystal plane index shifts, and the dominant crystal plane changes beyond the original crystal's main growth direction;

[0038] The recrystallization initiation temperature measured by DSC decreased by no less than 10℃, indicating that the stability of the crystal phase is controllable and adjustable.

[0039] Furthermore, after the crystal structure is directionally controlled, the solid-phase product exhibits the following two performance indicators:

[0040] At 303.15 K, 10 s -1The dynamic viscosity measured at the shear rate is less than 100 mPa·s;

[0041] Solid CO2 loading The proportion of solid phase CO2 load shall not be less than 90% of the total CO2 load. The total CO2 load was determined by acid hydrolysis and calculated using mass conservation.

[0042] Furthermore, the solid-phase CO2 loading The percentage was determined through the following steps:

[0043] The absorbent system after absorbing CO2 was allowed to stand and separate to obtain two parts: a solid phase and a liquid phase.

[0044] The solid-phase CO2 loading in the solid and liquid phases was determined by acid hydrolysis. ;

[0045] Solid CO2 loading The ratio is calculated to the total CO2 load, which is obtained by the mass difference method or the integral method. The resulting ratio is used to evaluate the solid phase enrichment capacity.

[0046] Furthermore, the process of screening out the types and doping ratios of crystal phase modifiers includes:

[0047] The range of dominant structure factors for the target crystal phase structure was determined based on the quantitative structure-activity relationship model, which was used to determine the CO2 loading in the solid phase. Not less than 0.90 × total load, and viscosity Not exceeding 1.5 times the average liquid viscosity of the absorbent system;

[0048] Set the grain size D target With crystallinity CrI target Target range, grain size The crystallinity is 60-80 nm. It is 65% to 80%;

[0049] Construct a database of crystal phase regulator effects to record the effects of different crystal phase regulator types and their doping ratios (0–10 wt%) on grain size. and crystallinity Regulatory response behavior;

[0050] A multi-objective optimization algorithm is used, preferably grid search or Bayesian optimization, to screen the types and doping ratios of crystal phase regulators that meet the target crystal phase structure parameters.

[0051] The selected crystal phase modifiers and their doping ratios were used for experimental verification. The measured target crystal phase structure and performance data were fed back into the quantitative structure-property relationship model for iterative updates, forming a three-dimensional closed-loop optimization system of crystal phase structure regulation, performance indicators, and crystal phase modifier screening.

[0052] By employing the above technical solution, the present invention provides a method for optimizing the solid-phase performance of CO2 phase change absorbers based on crystal phase structure regulation, which has at least the following beneficial effects:

[0053] 1. The method of directional control of crystal phase structure with machine learning assistance proposed in this invention to optimize the solid phase performance of CO2 absorbent is not only highly innovative and feasible, but also widely applicable to the development and industrial application of CO2 capture materials. It breaks through the limitations of traditional absorbent control that relies on experience and single-variable regulation, and provides a new path for efficient carbon capture and resource utilization.

[0054] 2. The method proposed in this invention achieves the precise construction of low-viscosity, high-CO2-load solid products with a solid-phase loading ratio of not less than 90%. It has a reversible closed-loop design feature of structure-performance-regulator and is suitable for various scenarios such as CO2 absorption-storage-conversion.

[0055] 3. This invention aims to solve the technical problems of existing CO2 phase change absorbers, such as uncontrollable crystal phase structure, high product viscosity, limited solid CO2 load, and lack of quantitative control methods during solid phase precipitation. This method integrates crystal engineering methods and machine learning-driven modeling strategies, and achieves coupled optimization of the rheology and carbon enrichment capacity of the absorption product based on the multi-parameter synergistic control of the crystal phase structure. Attached Figure Description

[0056] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0057] Figure 1 This is a flowchart illustrating the optimization of the solid-phase properties of the CO2 phase change absorbent in this invention;

[0058] Figure 2 This is a polarized light micrograph of the solid particles in this invention;

[0059] Figure 3 This is a particle size analysis curve of solid particles under different CO2 absorption loads in this invention. Detailed Implementation

[0060] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. This will allow for a full understanding of how the present application uses technical means to solve technical problems and achieve technical effects, and to facilitate its implementation.

[0061] This embodiment proposes a method for optimizing the solid-phase performance of CO2 phase change absorbers based on crystal phase structure regulation. This falls under the category of novel phase change absorber material design and intelligent regulation technology, and can also be applied to interdisciplinary fields such as carbon capture, carbon mineralization, absorber screening, and material structure-property relationship analysis. The method first controls the type and doping ratio of the crystal phase regulator to achieve targeted regulation of crystal phase structure parameters such as crystallinity, grain size, and microstrain in the absorber system. Then, based on experimental data, a nonlinear quantitative structure-property relationship model (using random forest regression and SHAP analysis) is constructed between the crystal phase structure parameters and the solid-phase CO2 load and system viscosity to identify the dominant structural factors and optimize the regulation path in reverse. Figure 1 As shown in the figure, this method enables the precise construction of low-viscosity, high-CO2-loading solid-phase products with a solid-phase loading ratio of not less than 90%. It features a reversible closed-loop design characteristic of structure-performance-regulator and is applicable to various scenarios such as CO2 absorption-storage-conversion.

[0062] Example 1: Liquid-solid phase change absorption experiment and solid phase properties and structure analysis under conditions without crystal phase regulator.

[0063] I. Preparation of the absorbent system

[0064] A B1E2 absorbent system was prepared by mixing 1,4-butanediamine (BDA) and ethylene glycol (EG) at a molar ratio of 1:2. This absorbent system undergoes a liquid-solid phase transition during CO2 absorption, precipitating a CO2-enriched solid product (hereinafter referred to as BESP), which meets the requirements of an absorbent system that undergoes a liquid-solid phase transition and precipitates a solid product during CO2 absorption.

[0065] II. Analysis of Absorption Performance and Phase Transition Behavior

[0066] To clarify the CO2 absorption behavior and phase transition characteristics of the B1E2 absorbent system under conditions without a phase regulator, samples were collected at different total loads (T). L The distribution data of CO2 in the liquid and solid phases under the following conditions are shown in Table 1.

[0067] Table 1. CO2 distribution and solid phase ratio of B1E2 at different absorption stages

[0068]

[0069] Table 1 shows that as the total CO2 load in the solid phase increases, the CO2 content in the liquid phase gradually decreases, while the CO2 load in the solid phase continuously increases. This indicates that during the gradual accumulation of CO2 concentration, the system undergoes a transformation from a homogeneous liquid phase to a heterogeneous liquid-solid separation structure. This process not only reflects the structural evolution of the absorbent system during the reaction but also reveals the kinetic trend of CO2 migration and enrichment in the rich phase (solid phase).

[0070] Especially at the end of absorption (T L At a total CO2 loading of 0.90 mol / mol, the solid phase CO2 loading reached 68.89%, with a solid mass fraction of 51.01%. This indicates that more than half of the mass of the absorbent system has undergone phase change and precipitated into a solid form, with CO2 mainly concentrated in this solid product. This "phase-separated enrichment" ability of CO2 in the absorbent system is an important characteristic that distinguishes liquid-solid phase change absorbents from traditional liquid-phase absorbents. Furthermore, it was observed that at a total loading of T... L Upon reaching a concentration of 0.6 mol / mol, the absorbent system gradually transformed from a transparent state to a milky white gel-like substance, eventually forming a settleable solid phase with a significantly increased viscosity. The solid particles exhibited a micron-sized polydisperse morphology, such as... Figure 2 As shown. Laser particle size analysis confirmed that D 50 During absorption, the particle size increased from 3.69 μm to 135.6 μm, indicating significant growth and aggregation behavior. Figure 3 As shown in the figure. This phenomenon indicates that although the B1E2 absorbent system can effectively achieve phase change and CO2 enrichment under conditions without crystalline phase regulation, the large particle size and severe aggregation of the solid phase particles lead to the system ultimately exhibiting a high-viscosity gel state (>200 mPa·s), posing a challenge to subsequent separation and recycling.

[0071] III. Structural Analysis of Solid Products

[0072] The crystal structure of BESP was characterized using various methods, and the main crystal structure parameters were extracted as follows: solid phase CO2 loading (mol / mol), solid phase loading percentage (SL) (%), dynamic viscosity (mPa·s), and crystallinity. (%), grain size D (nm), D 90 Particle size (μm), lattice defect density (cm) -2 ), lattice microstrain FWHM (°), main peak offset (°) and standard deviation of particle size distribution (μm).

[0073] The above parameters meet the crystal phase control standard proposed in this invention, indicating that even without the introduction of a control agent, the B1E2 absorbent system can generate a solid product with moderate crystallinity, suitable grain size, lattice micro-strain and main peak broadening characteristics under CO2 absorption induction.

[0074] IV. Conclusion

[0075] This embodiment verifies that, without a phase modifier, the B1E2 absorbent system can induce the formation of a solid-phase product during CO2 absorption. Although its crystal structure parameters (such as crystallinity, particle size distribution, and lattice defect density) partially meet the index range proposed in this invention, its dynamic viscosity remains high (>200 mPa·s). This indicates that without phase structure regulation, the system's CO2 solid-phase enrichment capacity and rheological properties have not yet reached synergistic optimality, requiring the introduction of a modifier to achieve orderly adjustment of the crystal structure. This embodiment provides a basic reference and comparative standard for the study of the structure-property relationship and the screening of modifiers in subsequent embodiments.

[0076] Example 2: Verification experiment on the optimization of crystal phase structure and improvement of solid phase performance by introducing crystal phase regulator.

[0077] To verify the effect of phase modifiers on the performance of CO2 liquid-solid phase change absorbents, a base solution (B1E2) was prepared by mixing BDA and EG at a molar ratio of 1:2. 5 wt% of 2-methylaminoethanol (MAE) and 2-amino-2-methyl-1-propanol (AMP) were introduced as phase modifiers, respectively. A control group consisting of the B1E2 system without the modifiers was set up. Experimental conditions were the same as in Example 1. The absorption performance, rheological behavior, and solid-phase crystal structure of the absorbent system were systematically characterized.

[0078] Table 2 compares and shows the trends of different absorbent systems in terms of solid-phase CO2 load, system viscosity, and crystal structure parameters.

[0079] Table 2 Comparison of absorption performance and crystal phase parameters of each group of absorbents

[0080]

[0081] The results in Table 2 show that the introduction of the phase modifier significantly increased the solid loading ratio (SL), reaching 94.2% and 95.5% in the MAE-controlled group and the AMP-controlled group, respectively, which is significantly higher than the 90.7% of the control group. This indicates that the phase modifier can effectively promote the enrichment of CO2 into the solid phase. In terms of dynamic viscosity, both the MAE-controlled group and the AMP-controlled group significantly fluidized the absorption system, and the system viscosity decreased by more than 60%, which improved the material transfer and regeneration operation conditions.

[0082] Regarding crystal structure, the crystal phase modifier significantly reduced the crystallinity of the solid product (from 63.7% to 49.2% and 46.3%), increased the main peak FWHM, and reduced the particle size (D). 90 The decrease in microstrain (from 135.6 μm to 69.4 μm) indicates a trend towards disorder in the crystal structure, which is beneficial for controlling the gel formation rate and reducing macroscopic rheological resistance. Simultaneously, the crystal phase modifier caused an increase in lattice microstrain (to 0.0034), an increase in defect density, and a slight shift in the main peak, reflecting directional perturbation of the crystal structure under regulation, which helps to form a thermally unstable, easily desorbed CO2-rich phase.

[0083] In summary, the introduction of crystal phase regulators can achieve the goal of regulating solid-phase products with low crystallinity, small particle size, and abundant structural defects through directional perturbation of crystal phase structure, thereby significantly improving CO2 absorption performance and controllable rheological properties, and further verifying the core concept of this invention regarding "performance optimization driven by crystal phase regulation".

[0084] Example 3: Modeling and verification of the structure-property relationship between crystal structure and solid-state properties.

[0085] To clarify the influence mechanism of crystal phase structure on solid-phase CO2 loading and system viscosity performance, and to establish a quantitative structure-activity relationship model between crystal phase structure parameters and solid-phase performance indicators, thereby providing a theoretical basis for the screening of crystal phase regulators and system optimization, this embodiment carried out modeling and interpretation analysis based on machine learning.

[0086] I. Experimental Data Acquisition and Feature Design

[0087] This embodiment is based on the experimental data from Embodiments 1 and 2, and supplemented by additional experiments. Twenty sets of samples were collected, and their crystal structure parameters and corresponding solid-state property parameters were measured. Specific feature definitions are as follows:

[0088] Input feature vector Output feature vector ,in, The loading of CO2 in the solid phase (mol CO2 / mol amine); The system viscosity (mPa·s) of the solid product was measured using a rheometer.

[0089] II. Model Construction and Evaluation

[0090] A nonlinear fitting model is established using Random Forest Regressor (RFR). The model parameters are as follows: number of trees (nestimators) 100; maximum depth (maxdepth) 6; minimum number of split samples 4. During model training, all samples are Z-score normalized, and 5-fold cross-validation is used to evaluate generalization performance. The prediction performance is as follows:

[0091] Prediction: R 2 = 0.912, MSE = 0.0036 mol 2 / mol 2 ;

[0092] Prediction: R 2 = 0.877, MSE = 172 mPa²·s².

[0093] III. Structure-Property Relationship Analysis

[0094] Using the SHAP (Shapley Additive Explanations) method to interpret the model, we found that:

[0095] (1) Grain size D and crystallinity It is an influence The main positive factors;

[0096] (2) Main peak offset and lattice microstrain Regarding the viscosity of the system A significant positive correlation was observed, indicating that the greater the lattice distortion and the shift of the main peak, the more viscous the system.

[0097] (3) Standard deviation of particle size distribution With system viscosity The positive correlation indicates that uneven particle distribution leads to decreased liquidity.

[0098] IV. Model Backward Optimization Design and Experimental Verification

[0099] Reverse design based on structure-property model:

[0100] Target solid-state performance indicators: ≥ 0.81 mol / mol ≤ 500 mPa·s;

[0101] Target crystal structure parameter setting: D target = 6580nm, CrI target = 6880%.

[0102] From the database of crystal phase modifiers, MAE (N-methylaminoethanol) doping at 6 wt% was selected as the most suitable.

[0103] Verification experiments show that:

[0104] Crystal structure parameters: D = 73.5 nm. = 74.3%, = 0.17%, = 0.012 nm -2 , = 0.13°, = 4.8μm;

[0105] Solid phase performance indicators: = 0.834 mol / mol = 470 mPa·s;

[0106] Solid-phase CO2 load accounted for 91.3%.

[0107] V. Practical Operation Instructions for the Model

[0108] All model operations were performed in Python 3.9, using scikit-learn to implement random forest training and prediction. SHAP analysis used the shap library (v0.41.0), and the illustrations are used for feature contribution visualization. Image analysis included:

[0109] The lattice defect density of the TEM image was obtained by ImageJ counting. Value; SEM images were analyzed using a particle size measurement plugin to calculate the standard deviation of particle size distribution. (Sampling number ≥ 100 particles); Particle size and XRD data analysis were performed using NanoMeasurer and Origin2023, respectively.

[0110] The results show that the model predictions are in high agreement with the experiments. The quantitative structure-activity relationship model can effectively guide the screening of crystal phase regulators and realize closed-loop optimization of crystal phase structure regulation, performance indicators and crystal phase regulator screening.

[0111] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Since the above embodiments are substantially similar to the method embodiments, their descriptions are relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0112] The above embodiments provide a detailed description of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for optimizing the solid-phase performance of CO2 phase change absorbers based on crystal phase structure regulation, characterized in that, The method includes the following steps: An absorbent system that can undergo a liquid-solid phase change and precipitate solid products during the absorption of carbon dioxide was selected; A crystal phase regulator is introduced into the absorbent system to induce the solid products to form a crystal structure during the absorption of CO2. Based on experimental data from the crystal structure formation process, a quantitative structure-property relationship (SPR) model was established to characterize the structure-property relationship between crystal structure parameters and solid-state performance indicators. These solid-state performance indicators include the solid-state CO2 loading. and system viscosity ; Based on the quantitative structure-activity relationship model, the dominant structural factors in the crystal phase structure parameters are identified by the characteristic importance analysis method, and used to guide the selection and ratio adjustment of crystal phase regulators, so as to achieve the directional regulation of low viscosity and high CO2 loading solid phase products. By defining the target crystal phase structure characteristics, combining the regulator database, and employing a multi-objective optimization algorithm, the types and doping ratios of crystal phase regulators that meet the target crystal phase structure characteristics are selected.

2. The method for optimizing the solid-phase performance of CO2 phase change absorbent based on crystal structure regulation according to claim 1, characterized in that, The selected absorbent system contains at least one alkaline component that can react with CO2 to form a carbamate or carbonate solid phase.

3. The method for optimizing the solid-phase performance of CO2 phase change absorbent based on crystal structure regulation according to claim 1, characterized in that, The crystal phase modifiers include one or more of the following categories: Small organic molecules containing hydroxyl or amino groups; sterically hindered amine compounds; Polar solvents or auxiliaries that can form stable hydrogen bonds or ion pairs with the absorption products.

4. The method for optimizing the solid-phase performance of CO2 phase change absorbent based on crystal structure regulation according to claim 1, characterized in that, The crystal structure parameters include crystallinity. Grain size lattice microstrain Lattice defect density Main peak offset Standard deviation of particle size distribution ; The crystal structure parameters are quantitatively characterized by one or more material structure analysis methods, including but not limited to: X-ray diffraction is used to determine crystallinity, full width at half maximum (FWHM) of the main peak, and grain size. The Williamson-Hall method is used to evaluate lattice microstrain. Infrared spectroscopy or Raman spectroscopy is used to analyze the configuration of functional groups and defect characteristics inside crystals; Scanning or transmission electron microscopy is used to observe crystal morphology and particle distribution. Differential scanning calorimetry is used to determine the thermal stability and recrystallization behavior of crystalline phases.

5. The method for optimizing the solid-phase performance of CO2 phase change absorbers based on crystal structure regulation according to claim 4, characterized in that, The nonlinear functional relationship between the crystal structure parameters and solid-state performance indicators is predicted and analyzed through machine learning modeling, the method including: Constructing input feature vectors and output feature vector ,in, This refers to the loading of CO2 in the solid phase; The viscosity of the solid product is the system viscosity. A random forest regression model is used to process the input feature vector. With output feature vector The mapping relationship between them is modeled to establish a quantitative structure-property relationship model to characterize the structure-property relationship between crystal phase structure parameters and solid phase properties; Based on the results of the quantitative structure-activity relationship model, the SHAP interpretation algorithm was used to identify crystallinity and other properties. Grain size The dominant structural factor is used to guide the selection and proportion adjustment of phase regulators to achieve directional control of low viscosity, high CO2 loading solid products.

6. The method for optimizing the solid-phase performance of CO2 phase change absorbent based on crystal structure regulation according to claim 1, characterized in that, The evolution path of the crystal phase structure is adjusted by the crystal phase regulator so that the crystal phase structure of the obtained solid product satisfies at least four of the following quantitative structural characteristics: Crystallinity measured by X-ray diffraction Keep it between 30% and 60%; Average grain size The wavelength is 200–500 nm, and D 90 Particle size not exceeding 600 nm; Lattice defect density Not less than 1.5×10 14 cm -2 ; The crystal phase configuration exhibits a low symmetry structure, accompanied by an increase in the full width at half maximum (FWHM) of the main XRD peak of ≥10%; Lattice microstrain Not less than 0.003; The characteristic crystal plane index shifts, and the dominant crystal plane changes beyond the original crystal's main growth direction; The recrystallization initiation temperature measured by DSC decreased by no less than 10℃, indicating that the stability of the crystal phase is controllable and adjustable.

7. The method for optimizing the solid-phase performance of CO2 phase change absorbent based on crystal structure regulation according to claim 5, characterized in that, After the crystal structure is directionally controlled, the solid product exhibits the following two performance indicators: At 303.15 K, 10 s -1 The dynamic viscosity measured at the shear rate is less than 100 mPa·s; Solid CO2 loading The proportion of solid phase CO2 load shall not be less than 90% of the total CO2 load. The total CO2 load was determined by acid hydrolysis and calculated using mass conservation.

8. The method for optimizing the solid-phase performance of CO2 phase change absorbers based on crystal structure regulation according to claim 7, characterized in that, The solid-phase CO2 load The proportion was determined through the following steps. include: The absorbent system after absorbing CO2 was allowed to stand and separate to obtain two parts: a solid phase and a liquid phase. The solid-phase CO2 loading in the solid and liquid phases was determined by acid hydrolysis. ; Solid CO2 loading The ratio is calculated to the total CO2 load, which is obtained by the mass difference method or the integral method. The resulting ratio is used to evaluate the solid phase enrichment capacity.

9. The method for optimizing the solid-phase performance of CO2 phase change absorbent based on crystal structure regulation according to claim 1, characterized in that, The process of screening out the types and doping ratios of crystal phase modifiers includes: The range of dominant structure factors for the target crystal phase structure was determined based on the quantitative structure-activity relationship model, which was used to determine the CO2 loading in the solid phase. Not less than 0.90 × total load, and viscosity Not exceeding 1.5 times the average liquid viscosity of the absorbent system; Set the grain size D target With crystallinity CrI target Target range, grain size The crystallinity is 60-80 nm. It is 65% to 80%; Construct a database of crystal phase modifier effects to record the effects of different crystal phase modifier types and their doping ratios on grain size. and crystallinity Regulatory response behavior; A multi-objective optimization algorithm was used to screen the types and doping ratios of crystal phase regulators that meet the target crystal phase structure parameters. The selected crystal phase modifiers and their doping ratios were used for experimental verification. The measured target crystal phase structure and performance data were fed back into the quantitative structure-property relationship model for iterative updates, forming a three-dimensional closed-loop optimization system of crystal phase structure regulation, performance indicators, and crystal phase modifier screening.

10. The method for optimizing the solid-phase performance of CO2 phase change absorbers based on crystal structure regulation according to claim 9, characterized in that, The doping ratio ranges from 0 to 10 wt%.

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