A design method for organic amine phase change absorption systems for carbon dioxide capture

Abstract

The application discloses a design method of an organic amine phase change absorption system for capturing carbon dioxide, and comprises the following steps: constructing and optimizing a three-dimensional molecular configuration of a phase separation agent to be predicted; performing molecular information analysis based on the molecular structure, thereby calculating an analysis factor related to the phase separation performance of the phase separation agent; inputting the analysis factor into a trained theoretical prediction model to obtain a phase separation performance prediction result of the phase separation agent; and selecting a suitable phase separation agent according to the prediction result and process conditions to construct the organic amine phase change absorption system. Based on the designed analysis factor and the theoretical prediction model, the phase separation behavior of the absorption system formed by the organic amine and different solvents can be accurately predicted, and a suitable phase separation agent can be screened according to the phase separation behavior, so that the organic amine phase separation system is rationally designed, thereby improving the problem that the screening and construction of the phase change absorption agent need to be completed through a large number of repeated experiments, and providing strong support for the efficient design and construction of the phase change absorption agent.

Description

Technical Field

[0001] This invention belongs to the field of carbon dioxide capture technology, and particularly relates to a design method for an organic amine phase change absorption system for capturing carbon dioxide. Background Technology

[0002] Organic amine-based chemical absorption is the primary method for capturing CO2 after combustion in the power industry. Organic amine absorbents have advantages such as high reaction rates and large absorption capacity, making them highly suitable for power plant flue gas with low CO2 concentrations and large volumes. However, their regeneration energy consumption is high, which increases the cost of power generation.

[0003] With the development of organic amine chemical absorbents, the regeneration energy consumption of common second-generation absorbents—mixed amine absorbents—can reach 2.4-3.5 GJ / t. 1 Compared to first-generation absorbents, second-generation absorbents can save up to 50% on regeneration energy consumption. Currently, most demonstration projects use mixed amine solutions as absorbents. For example, the W. a. Parish power plant near Houston, Texas, uses a mixed amine solution called KS-1, and the Guohua Power Jinjie Power Plant of the State Energy Group combines multiple organic amines, such as multi-stage amines and sterically hindered amines, into a composite solution for carbon capture. However, the regeneration energy consumption of second-generation absorbents is still at a relatively high level.

[0004] The third-generation novel absorbent—phase change absorbent—can separate into two phases, lean and rich, after absorption saturation. During regeneration, only the CO2-rich phase needs to be heated, significantly reducing latent and sensible heat of regeneration and exhibiting higher theoretical energy-saving potential. Phase change absorbents are composed of two or more components, mainly including organic amines (one or more absorbent components) and solvents (containing one or more solvents with phase-splitting capabilities—phase-splitting agents—and possibly one or more solvents without phase-splitting capabilities, such as water). The absorption performance of the absorbent primarily depends on the absorbent components, while the phase-splitting agent is crucial for the absorption process to undergo phase change. The phase-splitting agent does not directly load CO2 during absorption, making the entire reaction process relatively simple. After phase separation, the phase-splitting agent is enriched in the lean phase and can be directly sent to the absorption tower for recycling. When the volume of the absorbent solvent is constant, the addition of the phase-splitting agent will reduce the water content in the system, replacing some water and leading to a significant reduction in the heat of vaporization.

[0005] Current research on phase change absorbers is still insufficient, and the energy reduction effects of different phase change systems vary. Furthermore, the CO2 absorption principle and phase separation mechanism of phase change absorbers remain unclear, leading to the need for extensive and repeated experimental screening in the construction of phase change absorbers, which is highly unpredictable.

[0006] The aforementioned problems in the current development of phase change absorbers limit their theoretical advancement and further industrial applications. Therefore, there is an urgent need in this field to develop a rational design method for organic amine phase change absorbers to achieve efficient design and construction, supporting their further development. Summary of the Invention

[0007] Purpose of the invention: In order to improve the problem that the current screening and construction of phase change absorbents are largely blind, this invention provides a design method for organic amine phase change absorption systems for capturing carbon dioxide. This method is used to predict the phase separation behavior of absorption systems composed of organic amines and different solvents, and based on this, to screen out suitable phase separation agents, thereby rationally designing organic amine phase separation systems.

[0008] Summary of the Invention: To achieve the above objectives, this invention provides a method for designing an organic amine phase transition absorption system for capturing carbon dioxide, comprising the following steps:

[0009] S1: Construct and optimize the three-dimensional molecular configuration of the phase-separating agent to be predicted;

[0010] S2: Based on the optimized molecular structure, perform molecular information analysis to obtain molecular analysis data;

[0011] S3: Based on the obtained molecular analysis data, calculate the analytical factors related to the phase separation performance of the phase separation agent;

[0012] S4: Substitute the calculated analytical factors into the trained theoretical prediction model to obtain the prediction results of the phase separation performance of the phase separation agent;

[0013] S5: Based on the prediction results and process conditions, select a suitable phase separation agent to construct an organic amine phase change absorption system.

[0014] Optionally, step S1 involves constructing and optimizing the molecular structure using quantum chemical calculation software, including but not limited to Gaussian and Materials Studio.

[0015] Optionally, step S2 involves analyzing molecular information using molecular information analysis software, which includes, but is not limited to, any one or more of Gaussian, Multiwfn, and vmd.

[0016] Optionally, the molecular analytical data obtained in step S2 includes, but is not limited to, any one or more of the following: molecular structure, energy, bond vibrations, and wave functions.

[0017] Optionally, the analytical factors related to the phase separation performance of the phase separation agent in step S3 include, but are not limited to, any one or more of the following:

[0018] 1) Describe polarity-related molecular descriptors and physicochemical parameters, including polar surface area, polar surface area ratio, nonpolar surface area, nonpolar surface area ratio, molecular surface polarity index, dipole moment, and polarizability.

[0019] 2) Describe molecular descriptors and physicochemical parameters related to weak intermolecular interactions, including hydrogen bond acidity, hydrogen bond basicity, hydrogen bond interaction energy, van der Waals energy, and surface tension.

[0020] Optionally, the theoretical prediction model includes, but is not limited to, linear equations and / or multiple linear regression equations composed of analytical factors as the main parameters.

[0021] Optionally, the phase separation performance prediction result is a phase separation characteristic value, including but not limited to any one or more parameters such as lean / rich liquid volume ratio, rich phase CO2 percentage, phase separation load, and absorbent saturation load.

[0022] Beneficial effects:

[0023] Based on the given organic amine and solvent to be predicted, this invention can accurately predict the phase separation behavior of absorption systems composed of organic amines and different solvents by using designed analytical factors and theoretical prediction models. Based on this, suitable phase separation agents can be screened, and organic amine phase separation systems can be rationally designed. This improves the problem that the current screening and construction of phase change absorbents requires a large number of repeated experiments, and provides strong support for the efficient design and construction of phase change absorbents. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating the design method of the organic amine phase change absorption system in an embodiment of the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0026] The purpose of this embodiment is to predict the phase separation behavior of absorption systems composed of 2-amino-2-methyl-1-propanol (AMP) organic amine and different solvents, and to screen suitable phase separation agents based on this, thereby rationally designing organic amine phase separation systems.

[0027] like Figure 1 The figure shows a design method for an organic amine phase change absorption system for capturing carbon dioxide provided in this embodiment, which specifically includes the following steps:

[0028] S1: Construct and optimize the three-dimensional molecular configuration of the phase-separating agent to be predicted;

[0029] Specifically, molecular models of solvents such as water (H2O), ethanol (Eth), ethylene glycol (EG), dimethyl carbonate (DMC), and n-propanol (1-P) are constructed. It should be noted that the solvents mentioned here are randomly selected and are not a limitation of the operation.

[0030] Furthermore, the molecular configuration was optimized using quantum chemical calculation software to obtain a reasonable molecular configuration. This embodiment used Gaussian calculation software to obtain the (x, y, z) coordinates of different molecules as follows:

[0031] H2O: O1 (0.000, 0.000, 0.118), H1 (0.000, 0.762, 0.473), H2 (0.000, 0.762, 0.473);

[0032] Eth: C1 (-1.213, -0.246, -0.022), H1 (-1.259, -0.979, 0.790), H2 (-1.290, -0.777, -0.975), H3 (-2.079, 0.418, 0.074), C 2 (0.071, 0.561, 0.047), H4 (0.115, 1.289, -0.766), H5 (0.129, 1.111, 0.994), O2 (1.246, -0.256, -0.110), H6 (1.264, -0. 900, 0.609);

[0033] EG: C1 (-0.705, 0.563, 0.304), H1 (-1.239, 1.474, 0.025), H2 (-0.643 , 0.523, 1.400), C2 (0.686, 0.586, -0.293), H3 (0.628, 0.603, -1.384) , H4 (1.216, 1.484, 0.044), O1 (1.429, -0.597, 0.040), H5 (1.623, -0.5 82, 0.987), O2 (-1.487, -0.534, -0.184), H6 (-1.010, -1.351, 0.011);

[0034] DMC: O1 (1.081, -0.708, -0.000), O2 (-1.081, -0.708, -0.000), O3 (-0.000, 1.283, -0.000), C1 ( -0.000, 0.074, -0.000), C2 (2.346, -0.016, 0.000), C3 (-2.346, -0.016, 0.000), H1 (3.101, -0.800, 0.000), H2 (2.443, 0.6 03, -0.893), H3 (2.443, 0.603, 0.893), H4 (-3.101, -0.800, 0.000), H5 (-2.443, 0.603, -0.893), H6 (-2.443, 0.603, 0.893);

[0035] 1-P: O1 (-1.912, 0.093, -0.084), C1 (0.515, 0.530, -0.050), C2 (-0.605, -0.500, 0.0 18), C3 (1.896, -0.126, 0.023), H1 (0.396, 1.239, 0.776), H2 (0.416, 1.096, -0.981) , H3 (-0.535, -1.082, 0.946), H4 (-0.537, -1.199, -0.820), H5 (2.689, 0.626, -0.030 ), H6 (2.047, -0.828, -0.803), H7 (2.025, -0.679, 0.959), H8 (-2.043, 0.673, 0.677).

[0036] S2: Based on the optimized molecular structure, perform molecular information analysis to obtain molecular analysis data;

[0037] Based on the optimized molecular configuration, information such as molecular structure, energy, vibrational frequency, and wave function is calculated. In this embodiment, the information output file is obtained using Gaussian calculation software.

[0038] S3: Based on the obtained molecular analysis data, calculate the analytical factors related to the phase separation performance of the phase separation agent;

[0039] The output information, including molecular structure, energy, vibrational frequency, and wavefunction, is analyzed. This implementation uses the quantum chemical wavefunction analysis program Multiwfn to obtain several molecular descriptors. Combined with certain physicochemical parameters of the molecules, the analytical factors for the above solvents are obtained: A H2O B H2O C H2O D H2O A Eth BEth C Eth D Eth A EG B EG C EG D EG A DMC B DMC C DMC D DMC A 1-P B 1-P C 1-P D 1-P .

[0040] S4: Substitute the calculated analytical factors into the trained theoretical prediction model to obtain the prediction results of the phase separation performance of the phase separation agent;

[0041] By substituting the analytical factors of different solvents into the trained theoretical prediction model (Equation 1), the S values ​​of the above solvents were obtained. n Value: S H2O =145、S Eth =44、S EG =91、S DMC =13、S 1-P =31;

[0042] S n =aA n +bB n +cC n +dD n +e-----------------(Equation 1)

[0043] Among them, A n B n C n D n These represent different analytical factors, with a, b, c, and d being the simulation coefficients for the corresponding analytical factors, and S... n This refers to the phase separation characteristic value. In this embodiment, the smaller the phase separation characteristic value, the greater the likelihood of phase separation in the absorption system. Therefore, the phase separation performance of different phase-separating agents can be determined through threshold analysis. It should be noted that the theoretical prediction model and characteristic threshold mentioned here can be obtained through experimental data analysis and are not operational limitations.

[0044] S5: Based on the prediction results and process conditions, select a suitable phase separation agent to construct an organic amine phase change absorption system;

[0045] Experimental verification showed that the phase separation phenomenon of the absorption system obtained by combining the above solvents with AMP was consistent with the predicted results. The predicted phase separation characteristic values, ranked from largest to smallest, were: H2O > EG > Eth > threshold α > 1-P > DMC. Correspondingly, the experimentally obtained phase separation situations were: H2O - homogeneous, EG - homogeneous, Eth - homogeneous, 1-P - solid-liquid phase separation, and DMC - solid-liquid phase separation. Therefore, DMC and 1-P can be selected as organic solvents to construct solid-liquid phase separation systems when combined with AMP.

[0046] In this invention, the selection and construction of molecular analysis data, analytical factors, theoretical prediction models, and phase separation characteristic values ​​can be achieved based on limited experimental data analysis, with the optimization goal of improving the accuracy of phase separation behavior prediction, thereby providing strong support for the efficient design and construction of phase change absorbers.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for designing an organic amine phase transition absorption system for capturing carbon dioxide, characterized in that, Includes the following steps: S1: Construct and optimize the three-dimensional molecular configuration of the phase-separating agent to be predicted; S2: Based on the optimized molecular structure, perform molecular information analysis to obtain molecular analysis data, which includes at least one of molecular structure, energy, bond vibration and wave function information; S3: Based on the obtained molecular analysis data, calculate the analytical factors related to the phase separation performance of the phase separation agent. The analytical factors include at least one of molecular descriptors and physicochemical parameters describing polarity and molecular descriptors and physicochemical parameters describing weak intermolecular interactions. The polarity-related molecular descriptors and physicochemical parameters include polar surface area, polar surface area ratio, nonpolar surface area, nonpolar surface area ratio, molecular surface polarity index, dipole moment, and polarizability. The weak intermolecular interaction-related molecular descriptors and physicochemical parameters include hydrogen bond acidity, hydrogen bond basicity, hydrogen bond interaction energy, van der Waals energy, and surface tension. S4: Substitute the calculated analytical factors into the trained theoretical prediction model to obtain the phase separation performance prediction results of the phase separation agent. The theoretical prediction model includes a linear equation or a multiple linear regression equation composed of analytical factors as the main parameters. The phase separation performance prediction results are phase separation characteristic values, including at least one of the following: lean / rich liquid volume ratio, rich phase CO2 percentage, phase separation load, and absorbent saturation load. S5: Based on the prediction results and process conditions, select a phase separation agent that meets the requirements to construct an organic amine phase change absorption system.

2. The design method for the organic amine phase transition absorption system according to claim 1, characterized in that, Step S1 involves constructing and optimizing molecular structures using quantum chemical calculation software, including any one or more of Gaussian and Materials Studio.

3. The design method for the organic amine phase transition absorption system according to claim 1, characterized in that, Step S2 involves analyzing molecular information using molecular information analysis software, which includes any one or more of Gaussian, Multiwfn, and vmd.

4. The design method for the organic amine phase transition absorption system according to claim 1, characterized in that, The calculation of the analytical factors related to the phase separation performance of the phase separation agent in step S3 is implemented based on a quantum chemical wavefunction analysis program.

5. The design method for the organic amine phase transition absorption system according to claim 1, characterized in that, The theoretical prediction model was trained using limited experimental data, with the optimization goal of improving the accuracy of phase separation behavior prediction.

6. The design method for the organic amine phase transition absorption system according to claim 1, characterized in that, The phase separation characteristic value is used to determine the phase separation performance of the phase separation agent through threshold analysis, wherein the smaller the phase separation characteristic value, the greater the possibility of phase separation.

7. The design method for the organic amine phase transition absorption system according to claim 1, characterized in that, The organic amine phase change absorption system contains 2-amino-2-methyl-1-propanol (AMP) as an organic amine component, and the phase separation agent includes any one or more of water, ethanol, ethylene glycol, dimethyl carbonate, or n-propanol.

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