A method for evaluating the cyclic adsorption performance of a carbon dioxide adsorbent

Abstract

This disclosure relates to a method for evaluating the cyclic adsorption performance of a carbon dioxide adsorbent. The method includes: S1, subjecting the adsorbent to be tested to impurity removal treatment in a thermogravimetric analyzer followed by multiple adsorption-desorption tests to obtain a thermogravimetric cycle curve; S2, obtaining parameters E1, F1, and H based on the thermogravimetric cycle curve and a formula. i and I i S3. Obtain the first and second fitted curves; S4. Based on E1, E i H2, I2, F1, F i The performance of the adsorbent under test can be evaluated using one or more of the first and second fitted curve functions. Using the above method, a relatively standard evaluation method for adsorbent performance based on thermogravimetric analysis can be established. This method allows for the selection of appropriate parameters for qualitative analysis of various adsorbents according to actual usage conditions. By comparing the qualitative analysis results, a suitable adsorbent can be selected, resulting in a wide range of applications and strong applicability.

Description

Technical Field

[0001] This disclosure relates to the field of carbon dioxide adsorption, and more specifically, to a method for evaluating the cyclic adsorption performance of a carbon dioxide adsorbent. Background Technology

[0002] Currently, the use of fossil fuels and industrial hydrogen production processes generate large amounts of CO2, exacerbating the greenhouse effect. Therefore, the capture, storage, and conversion of carbon dioxide have gradually become key areas for greenhouse gas emission reduction and control. In recent years, the adsorption and desorption cycle reaction method using calcium-based adsorbents to separate CO2 has attracted great interest and extensive research from scholars worldwide.

[0003] Reference (Preparation and CO2 Cyclic Adsorption Performance of Coated Modified Nano-Calcium Carbonate, Wang Yan, Zhejiang University, 2014) evaluates the adsorption and cycling performance of modified nano-calcium carbonate adsorbent using thermogravimetric analysis (TGA). It proposes parameters for qualitative and quantitative analysis of the adsorbent's cycling stability: adsorption capacity and decay rate, and defines calculation methods for these parameters, applying them to the analysis of the modified adsorbent. Reference (Screening of Calcium-Based Precursor Materials for CaO High-Temperature Adsorption and Capture of CO2 to CaO, Zhang Mingming et al., Science in China: Chemistry, 2012) prepares CaO materials using natural calcium sources and chemical reagents. It evaluates the adsorption capacity and long-term cycling stability of CaO using TGA and proposes new physical quantities for calculating and evaluating adsorption capacity.

[0004] Existing technologies utilize thermogravimetric analysis (TGA) to conduct experiments on the long-term cycling stability of prepared adsorbent materials, defining new parameters for evaluation and analysis. These new parameters, along with existing traditional parameters, are used to describe and evaluate cycling performance. However, these descriptions and evaluations are mostly qualitative and lack precise definitions, formula explanations, and applicable ranges for the physical quantities used in the evaluation, making it difficult to use for standardized evaluation of different types of adsorbents. Summary of the Invention

[0005] The purpose of this disclosure is to provide a method for evaluating the cyclic adsorption performance of carbon dioxide adsorbents, in order to solve the problems in the prior art that lack accurate definitions, formula descriptions and applicable scopes of the physical quantities used in the evaluation, and that it is difficult to use it for unified standard evaluation of different types of adsorbents.

[0006] To achieve the above objectives, this disclosure provides a method for evaluating the cyclic adsorption performance of a CO2 adsorbent, the method comprising:

[0007] S1. After removing impurities from the adsorbent in a thermogravimetric analyzer, perform multiple adsorption-desorption tests to obtain the thermogravimetric cycle curve.

[0008] S2. Calculate the regeneration rate H of the adsorbent in the i-th adsorption-desorption test according to Equation 1. i The unit is %:

[0009]

[0010] Wherein, E1 represents the weight percentage of the adsorbent after desorption of impurities in the first adsorption-desorption test, expressed in wt%; E i The percentage by weight of the adsorbent after CO2 desorption in the i-th adsorption-desorption test is expressed in wt%.

[0011] The rate of change of adsorption amount I in the i-th adsorption-desorption test is calculated according to Equation 2. i The unit is %:

[0012]

[0013] Wherein, F1 represents the percentage by weight of CO2 adsorbed by the test adsorbent in the first adsorption-desorption test, expressed in wt%; F i The percentage of CO2 adsorbed by the adsorbent in the i-th adsorption-desorption test is expressed in wt%.

[0014] S3, Regeneration rate H during all adsorption-desorption tests i The first data set is formed by combining the first data set with the corresponding cycle number i; the first data set is fitted to obtain the first fitting curve function H = f(i); the adsorption change rate I during all the adsorption-desorption tests is... i The second data set is formed by combining the corresponding loop count i; the second data set is fitted to obtain the second fitted curve function I = f(i);

[0015] S4, according to E1, E i F1, F i The performance of the adsorbent to be tested is evaluated by one or more of the following: H2, I2, the first fitting curve function, and the second fitting curve function; where i is a positive integer and i≥2.

[0016] Optionally, the adsorbent stability of the test adsorbent can be evaluated based on H2 and the first fitted curve function.

[0017] Optionally, the adsorption stability of the adsorbent to be tested can be evaluated based on I2 and the second fitted curve function.

[0018] Optionally, based on F1 and F i Evaluate the adsorption capacity of the adsorbent to be tested.

[0019] Optionally, the adsorption-desorption test is performed more than 5 times.

[0020] Optionally, the evaluation method further includes: S5, calculating the change J of the adsorption amount of the adsorbent in two consecutive adsorption-desorption tests according to Equation 3. i The unit is wt%:

[0021] J i =F i-1 -F i Formula 3

[0022] Among them, F i-1 In the (i-1)th adsorption-desorption test, the percentage of CO2 adsorbed by the adsorbent relative to the weight of the adsorbent being tested, where i is a positive integer and i≥2; when the change in adsorption amount J i <0 indicates that the adsorption performance of the adsorbent in the i-th adsorption-desorption test is improved compared to the (i-1)-th adsorption-desorption test; when the change in adsorption amount J i A value greater than 0 indicates that the adsorption performance of the adsorbent in the i-th adsorption-desorption test is lower than that in the (i-1)-th adsorption-desorption test.

[0023] Optionally, the adsorption-desorption test includes: contacting the adsorbent after impurity removal with CO2-rich gas at an adsorption temperature for adsorption treatment; until the weight of the adsorbent after impurity removal stabilizes to obtain a carbon-rich adsorbent; and regenerating the carbon-rich adsorbent at a regeneration temperature until the weight of the carbon-rich adsorbent stabilizes to obtain a regenerated adsorbent.

[0024] Optionally, the evaluation method further includes calculating the limiting cycle number x2 when the adsorbent to be tested is completely ineffective according to Equation 4:

[0025] I(i)=0; Formula 4

[0026] The larger the value of x2, the longer the ultimate lifetime of the adsorbent to be tested.

[0027] Optionally, the evaluation method further includes rounding the limit cycle number x2 to obtain the maximum cycle number M of the adsorbent to be tested; the larger the value of the maximum cycle number M, the larger the maximum cycle number of the adsorbent to be tested.

[0028] Application of the evaluation method described in the first aspect of this disclosure in the field of carbon dioxide adsorption.

[0029] Using the above technical solution, thermogravimetric analysis is used to obtain thermogravimetric cycle curves. Based on these curves, the weight percentage E1 of the adsorbent after desorption of impurities and the weight percentage F1 of CO2 adsorbed by the adsorbent in the first adsorption-desorption test are obtained, as well as the weight percentage E of the adsorbent after desorption of CO2 in the i-th adsorption-desorption test. i And the percentage of CO2 adsorbed by the test adsorbent by weight F relative to the weight of the test adsorbent. i The parameters were defined in detail, and the regeneration rate H of the adsorbent was calculated using a formula. i and the rate of change of adsorption amount I i Then, based on the regeneration rate H of the adsorbent... i and the rate of change of adsorption amount I i A mathematical model is fitted to obtain a first and a second fitting curve. The performance of the adsorbent is evaluated based on the detailed defined parameters and the fitting curves. Using the above method, a relatively standard evaluation method for adsorbent performance based on thermogravimetric analysis can be established. This method allows for the selection of appropriate parameters for qualitative analysis of various adsorbents according to actual application conditions. By comparing the qualitative analysis results, a suitable adsorbent can be selected, resulting in a wide range of applications and strong applicability.

[0030] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0031] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0032] Figure 1 The thermogravimetric cycle curve is used in the evaluation method of the cyclic adsorption performance of a carbon dioxide adsorbent disclosed in this invention. Detailed Implementation

[0033] The following provides a detailed description of specific embodiments of this disclosure. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit this disclosure.

[0034] This disclosure provides a method for evaluating the cyclic adsorption performance of a CO2 adsorbent, the method comprising:

[0035] S1. After removing impurities from the adsorbent in a thermogravimetric analyzer, perform multiple adsorption-desorption tests to obtain the thermogravimetric cycle curve.

[0036] S2. Calculate the regeneration rate H of the adsorbent in the i-th adsorption-desorption test according to Equation 1.i The unit is %:

[0037]

[0038] Wherein, E1 represents the weight percentage of the adsorbent after desorption of impurities in the first adsorption-desorption test, expressed in wt%; E i The percentage by weight of the adsorbent after CO2 desorption in the i-th adsorption-desorption test is expressed in wt%.

[0039] The rate of change of adsorption amount I in the i-th adsorption-desorption test is calculated according to Equation 2. i The unit is %:

[0040]

[0041] Wherein, F1 represents the percentage by weight of CO2 adsorbed by the test adsorbent in the first adsorption-desorption test, expressed in wt%; F i The percentage of CO2 adsorbed by the adsorbent in the i-th adsorption-desorption test is expressed in wt%.

[0042] S3, Regeneration rate H during all adsorption-desorption tests i The first data set is formed by combining the first data set with the corresponding cycle number i; the first data set is fitted to obtain the first fitting curve function H = f(i); the adsorption change rate I during all the adsorption-desorption tests is... i The second data set is formed by combining the corresponding loop count i; the second data set is fitted to obtain the second fitted curve function I = f(i);

[0043] S4, according to E1, E i F1, F i The performance of the adsorbent to be tested is evaluated by one or more of the following: H2, I2, the first fitting curve function, and the second fitting curve function; where i is a positive integer and i≥2.

[0044] Using the above technical solution, thermogravimetric analysis is used to obtain thermogravimetric cycle curves. Based on these curves, the weight percentage E1 of the adsorbent after desorption of impurities and the weight percentage F1 of CO2 adsorbed by the adsorbent in the first adsorption-desorption test are obtained, as well as the weight percentage E of the adsorbent after desorption of CO2 in the i-th adsorption-desorption test. i And the percentage of CO2 adsorbed by the test adsorbent by weight F relative to the weight of the test adsorbent. iThe parameters were defined in detail, and the regeneration rate H of the adsorbent was calculated using a formula. i and the rate of change of adsorption amount I i Then, based on the regeneration rate H of the adsorbent... i and the rate of change of adsorption amount I i A mathematical model is fitted to obtain a first and a second fitting curve. The performance of the adsorbent is evaluated based on the detailed defined parameters and the fitting curves. Using the above method, a relatively standard evaluation method for adsorbent performance based on thermogravimetric analysis can be established. This method allows for the selection of appropriate parameters for qualitative analysis of various adsorbents according to actual application conditions. By comparing the qualitative analysis results, a suitable adsorbent can be selected, resulting in a wide range of applications and strong applicability.

[0045] In one embodiment, the evaluation of the adsorbent according to this disclosure can be qualitatively analyzed from its stability and adsorption capacity. Stability includes adsorbent stability and adsorption capacity stability. In this embodiment, adsorbent stability refers to the change in weight of the adsorbent after impurity removal during adsorption-desorption tests; a smaller change in weight indicates good adsorbent stability, and vice versa. Adsorption capacity stability refers to the change in the amount of carbon dioxide absorbed by the adsorbent during adsorption-desorption tests; a smaller change in the amount of carbon dioxide absorbed indicates good adsorption capacity stability, and vice versa.

[0046] In one embodiment, when both the adsorbent stability and the adsorption capacity stability of the adsorbent are good, it indicates that the adsorbent has good stability.

[0047] In one embodiment, step S4 further includes:

[0048] S41. Evaluate the adsorbent stability of the test adsorbent based on H2 and the first fitted curve function;

[0049] S42. Evaluate the adsorption stability of the adsorbent to be tested based on I2 and the second fitted curve function;

[0050] S43, Based on F1 and F i Evaluate the adsorption capacity of the adsorbent to be tested.

[0051] The specific evaluation methods for the adsorbent stability of the test adsorbent include:

[0052] S411. Determine the shape of the first fitted curve: The closer the shape of the first fitted curve is to a straight line, the more uniform the weight change of the adsorbent to be tested is.

[0053] S412. Determine the slope of the above approximate straight line. The closer the slope of the above approximate straight line is to 0, the better the adsorbent stability of the adsorbent to be tested.

[0054] S413. Determine the H2 value. The closer the H2 of the test adsorbent is to 100%, the better the adsorbent stability of the test adsorbent.

[0055] The specific evaluation methods for the adsorption stability of the adsorbent to be tested include:

[0056] S421. Determine the shape of the second fitting curve: The closer the shape of the second fitting curve is to a straight line, the more uniform the change in the adsorption amount of the adsorbent to be tested.

[0057] S422. Determine the slope of the above approximate straight line. The closer the slope of the above approximate straight line is to 0, the better the stability of the adsorption amount of the adsorbent to be tested.

[0058] S423. Determine the I2 value. The closer I2 is to 100%, the better the stability of the adsorption capacity of the adsorbent being tested.

[0059] Among them, according to F1 and F i The specific evaluation methods for assessing the adsorption capacity of the test adsorbent include:

[0060] S43, Place F1 and F i A third data set is formed by combining the data with the corresponding cycle number i; a graph is plotted on the third data set to obtain an adsorption amount line graph; the adsorption amount of the adsorbent is determined based on the adsorption amount line graph.

[0061] In one specific embodiment, the test adsorbent A and test adsorbent B are evaluated using steps S1 to S3 respectively, and the following parameters are obtained: the E1 value of test adsorbent A during the first adsorption-desorption test is denoted as E. 1A and E 1B E during the i-th adsorption-desorption test i Value is E iA and E iB The F1 value during the first adsorption-desorption test is recorded as F. 1A and F 1B ; F during the i-th adsorption-desorption test i Value is F iA and F iB The regeneration rate H2 of the adsorbent in the second adsorption-desorption test is calculated as H. 2A and H 2B The rate of change in adsorption capacity I2 in the second adsorption-desorption test is calculated as I. 2A and I 2BFurthermore, the first and second fitted curve functions are obtained; the adsorption performance of adsorbent A and adsorbent B is evaluated using step S4:

[0062] S41. Evaluate the adsorbent stability of the test adsorbent:

[0063] S411. Compare the first fitted curves of the test adsorbent A with those of the test adsorbent B. When one of them is closer to a straight line, it indicates that the weight change of the test adsorbent is more uniform.

[0064] S412. When the first fitting curves of the test adsorbent A and the test adsorbent B are both close to straight lines, compare the slopes of the two approximate straight lines. When one of the slopes of the two approximate straight lines is closer to 0, it indicates that the test adsorbent has better adsorbent stability.

[0065] S413. When the slopes of the first fitted curves of adsorbent A and adsorbent B are equal, compare the H of adsorbent A with that of adsorbent B. 2A and H 2B When H 2A Greater than H 2B This indicates that adsorbent A has better adsorbent stability than adsorbent B, when H... 2A Less than H 2B This indicates that adsorbent A has worse adsorbent stability than adsorbent B.

[0066] S42. Evaluate the adsorption stability of the adsorbent:

[0067] S421. Compare the second fitting curves of the test adsorbent A and the test adsorbent B. When one of them is closer to a straight line, it indicates that the adsorption amount of the test adsorbent changes more uniformly.

[0068] S422. When the second fitting curves of the test adsorbent A and the test adsorbent B are both close to straight lines, compare the slopes of the two approximate straight lines. When one of the slopes of the two approximate straight lines is closer to 0, it indicates that the adsorption capacity stability of the test adsorbent is better.

[0069] S423. When the slopes of the second fitting curves of adsorbent A and adsorbent B are equal, compare the I of adsorbent A with that of adsorbent B. 2A and I 2B , when I 2A Greater than I 2B This indicates that adsorbent A has better adsorption stability than adsorbent B. 2A Less than I 2B This indicates that the adsorption stability of adsorbent A is worse than that of adsorbent B.

[0070] S43, Based on F1 and F i To evaluate the adsorption capacity of the test adsorbent: The adsorption capacity of test adsorbent A and test adsorbent B is evaluated using F... 1A F iA F 1B F iB The third data set is formed by combining the corresponding cycle number i; the adsorption amount is plotted on the third data set to obtain a line graph of the adsorption amount.

[0071] When the line graph of adsorbent A is above that of adsorbent B, it indicates that adsorbent A has a better adsorption capacity than adsorbent B.

[0072] When the line graph of adsorbent A is below that of adsorbent B, it indicates that adsorbent A has a worse adsorption capacity than adsorbent B.

[0073] In the above embodiments, when evaluating the catalyst to be tested, technicians can select appropriate data to compare multiple adsorbents according to specific usage requirements. For example, without considering the stability of the adsorbent and the stability of the adsorption amount, the adsorbent with the best adsorption amount in the 5th adsorption-desorption test can be qualitatively analyzed using the evaluation method in step S43, and a better adsorbent that meets the requirements can be selected.

[0074] The adsorbent used in this disclosure can be selected from solid carbon dioxide adsorbents, and the solid adsorbents used can adsorb carbon dioxide through physical adsorption or chemical adsorption.

[0075] In one embodiment, the method for removing impurities from the adsorbent to be tested disclosed herein is a conventional method in the art, and this application does not make any special requirements. For example, the impurity removal process includes: subjecting the adsorbent to be tested to high-temperature treatment under an inert atmosphere until the weight of the adsorbent to be tested stabilizes, thereby obtaining an adsorbent to be tested with impurities removed; wherein, the inert atmosphere used in the impurity removal process is selected from nitrogen and / or argon.

[0076] The adsorption-desorption test disclosed herein is a conventional method in the art, specifically comprising: contacting the impurity-removing adsorbent with CO2-rich gas at an adsorption temperature for adsorption treatment; until the weight of the impurity-removing adsorbent stabilizes to obtain a carbon-rich adsorbent; and regenerating the carbon-rich adsorbent at a regeneration temperature until the weight of the carbon-rich adsorbent stabilizes to obtain a regenerated adsorbent.

[0077] The method for generating thermogravimetric curves in this disclosure is a conventional choice in the art; specific data should be determined based on actual test conditions, such as... Figure 1As shown, the horizontal axis of the thermogravimetric cycle curve represents time (in minutes), and the vertical axis represents weight percentage and temperature (in wt% and ℃, respectively). The vertical axis represents the ratio of the real-time weight of the adsorbent to the weight of the adsorbent being tested in the thermogravimetric analyzer. In this embodiment, the trend of adsorbent change with temperature and time can be obtained, and the desired parameters can be more easily obtained from the thermogravimetric cycle curve. For example, the parameters could be the weight percentage E1 of the adsorbent after desorption of impurities in the first adsorption-desorption test, the weight percentage F1 of CO2 adsorbed by the adsorbent in the first adsorption-desorption test, and the weight percentage E of the adsorbent after desorption of CO2 in the i-th adsorption-desorption test. i And in the i-th adsorption-desorption test, the percentage of CO2 adsorbed by the adsorbent relative to the weight of the adsorbent being tested, F. i .

[0078] One specific implementation method, according to this disclosure Figure 1 The method for obtaining parameters from the thermogravimetric cycle curves shown includes: Curve A in the figure represents the impurity removal process. Specifically, the adsorbent is treated with a thermogravimetric analyzer to remove water and impurities. Therefore, the weight of the adsorbent gradually decreases until all water and impurities are removed, at which point the weight stabilizes. The value of the stable segment in curve A at this point represents the weight percentage E1 of the adsorbent after impurity removal, relative to the weight of the adsorbent under test, in the first adsorption-desorption test. Curve B in the figure represents the adsorption process. Specifically, the temperature is lowered to the adsorption temperature, the inert atmosphere is switched to a CO2-rich gas, and the adsorbent under test, after impurity removal, is allowed to adsorb CO2 from the CO2-rich gas at the adsorption temperature. Therefore, the weight gradually increases until the adsorbed CO2 is saturated, at which point the weight stabilizes. The difference between the values ​​of the stable curves in curve B at this point represents the weight percentage F1 of the adsorbent under test, relative to the weight of CO2 adsorbed by the adsorbent under test, in the first adsorption-desorption test. In the figure, curve C represents the regeneration process. Specifically, the CO2-rich gas is switched to an inert atmosphere, and the temperature is raised to the regeneration temperature to desorb the adsorbed carbon dioxide (CO2) from the carbon-rich adsorbent. Therefore, the weight gradually decreases until all CO2 is desorbed, at which point the weight stabilizes. The value in curve C at the point of switching to the adsorption test is the weight percentage E2 of the adsorbent after CO2 desorption in the second adsorption-desorption test. Additionally, curve P in the figure represents the i-th adsorption-desorption test. The value in curve P at the point of switching to the adsorption test is E2. i The value F represents the percentage by weight of the adsorbent after CO2 desorption in the i-th adsorption-desorption test, expressed in wt%, and is the difference F between the values ​​of the curves reaching stability. iThis refers to the percentage of CO2 adsorbed by the adsorbent in the i-th adsorption-desorption test, expressed in wt%. The curve may fluctuate slightly after reaching stability; this is normal and minor fluctuations generally do not affect the trend assessment.

[0079] To ensure the accuracy of the fitted curve function, this disclosure requires the collection of data from multiple cyclic adsorption-desorption tests, and the number of tests cannot be too few. This disclosure limits the number of adsorption-desorption tests to 5 or more, preferably 10 or more, and more preferably 15 or more.

[0080] The method disclosed herein for fitting a mathematical model to the first and second data sets is a conventional method in the art. It should be noted that when selecting different types of fitting functions (linear, parabolic, and exponential, etc.), the corresponding degree of fit R should be considered. 2 To ensure that the goodness of fit R of the first and second fitted curves is the same. 2 Above 0.99, the goodness of fit Rfit is... 2 This indicates the goodness of fit between the curve and the actual data; a higher goodness of fit means a more accurate fitted curve. However, there are also cases of poor goodness of fit, where the goodness of fit R0 of the first or second fitted curve is lower than the actual data. 2 If the value is less than 0.99, additional data can be added to improve the accuracy of the mathematical model fitting.

[0081] In one embodiment, the evaluation method further includes: S5, calculating the change J of the adsorption amount of the adsorbent in two consecutive adsorption-desorption tests according to Equation 3. i The unit is wt%:

[0082] J i =F i-1 -F i Formula 3

[0083] Among them, F i-1 In the (i-1)th adsorption-desorption test, the percentage of CO2 adsorbed by the adsorbent relative to the weight of the adsorbent being tested, where i is a positive integer and i≥2; when the change in adsorption amount J i <0 indicates that the adsorption performance of the adsorbent in the i-th adsorption-desorption test is improved compared to the (i-1)-th adsorption-desorption test; when the change in adsorption amount J i A value greater than 0 indicates that the adsorption performance of the adsorbent in the i-th adsorption-desorption test is lower than that in the (i-1)-th adsorption-desorption test.

[0084] The change J in the amount of adsorbent adsorbed in two consecutive adsorption-desorption tests. i A scatter plot was created with the corresponding number of cycles i. The result of the adsorption / desorption test for the i-th cycle was... i Value and the rest of Ji When the values ​​differ significantly, outliers are identified, and the cause is determined to be either systematic error, testing error, or significant adsorbent failure. In this embodiment, the outliers appearing in the i-th adsorption-desorption test are further analyzed to determine whether they are measurement errors. Then, it is further determined whether outliers not due to measurement errors are caused by significant adsorbent failure or increased cycle efficiency. Furthermore, the more frequent the occurrence of outliers not due to measurement errors, the worse the adsorption stability of the adsorbent.

[0085] In one embodiment, the evaluation method further includes calculating the limiting cycle number x2 at which the adsorbent to be tested completely fails, according to Equation 4:

[0086] I(i)=0; Formula 4

[0087] The larger the value of x2, the longer the ultimate lifetime of the adsorbent to be tested.

[0088] In a further embodiment, the maximum number of cycles M of the adsorbent to be tested is defined based on the limiting cycle number x2. The evaluation method further includes rounding the limiting cycle number x2 to obtain the maximum number of cycles M of the adsorbent to be tested. Specifically, when the limiting cycle number x2 is a positive integer, the maximum number of cycles M of the adsorbent to be tested is equal to the limiting cycle number x2. When the limiting cycle number x2 is a decimal, the maximum number of cycles M of the adsorbent is the integer part of the limiting cycle number x2. The larger the value of M, the larger the maximum number of cycles of the adsorbent to be tested.

[0089] Application of the evaluation method described in the first aspect of this disclosure in the field of carbon dioxide adsorption.

[0090] The present disclosure is further illustrated by the following examples, but the disclosure is not limited thereto. The thermogravimetric analyzer used in this disclosure is a STA449F3, manufactured by Netzsch GmbH, Germany. The adsorbent used in this disclosure is a self-made adsorbent from the Beijing Low Carbon Clean Energy Research Institute.

[0091] Example 1

[0092] Impurity removal treatment: Approximately 10 mg of the adsorbent to be tested is subjected to impurity removal treatment at 115°C and under a nitrogen atmosphere for 30 min until the weight of the adsorbent stabilizes, thus obtaining the impurity-removed adsorbent;

[0093] S1. Adsorption-desorption test: The nitrogen atmosphere was switched to a mixed atmosphere of nitrogen (85 vol%) and carbon dioxide (15 vol%), and the impurity-removing adsorbent was subjected to adsorption treatment at 40°C for 60 min until the weight of the adsorbent stabilized, yielding a carbon-rich adsorbent. The mixed atmosphere was then switched back to nitrogen, and the carbon-rich adsorbent was subjected to regeneration treatment at 100°C for 30 min until the weight of the carbon-rich adsorbent stabilized, yielding a regenerated adsorbent. The adsorption-desorption test was repeated 10 times to obtain the thermogravimetric cycle curve.

[0094] S2. Calculate the regeneration rate H of the adsorbent in the i-th adsorption-desorption test according to Equation 1. i The unit is %:

[0095]

[0096] Wherein, E1 represents the weight percentage of the adsorbent after desorption of impurities in the first adsorption-desorption test, expressed in wt%; E i The percentage by weight of the adsorbent after CO2 desorption in the i-th adsorption-desorption test is expressed in wt%.

[0097] The rate of change of adsorption amount I in the i-th adsorption-desorption test is calculated according to Equation 2. i The unit is %:

[0098]

[0099] Wherein, F1 represents the percentage by weight of CO2 adsorbed by the test adsorbent in the first adsorption-desorption test, expressed in wt%; F i The percentage of CO2 adsorbed by the adsorbent in the i-th adsorption-desorption test is expressed in wt%.

[0100] S3. Obtain the regeneration rate H for each adsorption-desorption test using Equation 1. i And the regeneration rate H during each adsorption-desorption test i The first data set is formed by combining the corresponding loop count i; the first data set is fitted to obtain the first fitted curve function H. i = -0.0035i + 0.9965, goodness of fit R 2 The value is 0.9481; the rate of change of adsorption amount I during each adsorption-desorption test is obtained using Equation 2. i And the rate of change of adsorption amount I during each adsorption-desorption test. i The second data set is formed by combining the corresponding loop count i; a mathematical model is then applied to the second data set to obtain the second fitted curve function I. i= -0.0455i + 0.9741, goodness of fit R 2 It is 0.9956;

[0101] S4, according to E1, E i F1, F i The performance of the adsorbent to be tested is evaluated by one or more of the following: H2, I2, the first fitting curve function, and the second fitting curve function.

[0102] S5. The change J of regenerated adsorption amount in two consecutive adsorption-desorption tests calculated according to Equation 3. i :

[0103] J i =F i-1 -F i Formula 3

[0104] The change in adsorption amount J i A scatter plot was prepared with the number of cycles i. From the above scatter plot, it can be seen that the outlier appeared in the change of regenerated adsorption amount in the first and second adsorption-desorption tests, J1 was 0.68wt%. Based on the above scatter plot, it can be inferred that the adsorbent to be tested was significantly deactivated after the first adsorption-desorption test.

[0105] S6. According to Equation 4, the limiting cycle number x2 when the adsorbent to be tested completely fails is calculated to be 21.41.

[0106] I(i)=0; Formula 4

[0107] The maximum number of cycles M for the adsorbent to be tested is defined as 21 based on the limiting cycle number x2.

[0108] Example 2

[0109] The evaluation method for the cyclic adsorption performance of the CO2 adsorbent is the same as in Example 1, except that the impurity removal treatment time is 60 min and the regeneration treatment temperature is 90℃.

[0110] The first fitted curve function H obtained i =-0.0002i 2 +0.004i+0.9949, goodness of fit R 2 The value is 0.9924; the second fitted curve function I is obtained. i = -0.036i + 0.9541, goodness of fit R 2 It is 0.9880;

[0111] Based on the calculated change J of regenerated adsorption amount in two consecutive adsorption-desorption tests. iThe scatter plot shows that the discrete value appears in the change of regenerated adsorption amount in the first and second adsorption-desorption tests, J1 is 0.53wt%. Based on the above scatter plot, it can be inferred that the adsorbent to be tested was significantly deactivated after the first adsorption-desorption test.

[0112] If the limit number of iterations x2 is 26.5, then the maximum number of iterations M is 26.

[0113] As can be seen from Embodiments 1 and 2 of this disclosure, the thermogravimetric cycle curves obtained by thermogravimetric analysis are used to obtain E1, F1, and E2. i and F i The parameters were defined in detail, and the regeneration rate H of the adsorbent was calculated using a formula. i and the rate of change of adsorption amount I i Then, based on the regeneration rate H of the adsorbent... i and the rate of change of adsorption amount I i By fitting a mathematical model, a first fitting curve and a second fitting curve are obtained. This enables the establishment of a relatively standard evaluation method for adsorbent performance based on thermogravimetric analysis. It allows for the selection of appropriate parameters for qualitative analysis of various adsorbents according to actual usage conditions. By comparing the qualitative analysis results, a suitable adsorbent can be selected. This method has a wide range of applications and strong applicability.

[0114] The preferred embodiments of this disclosure have been described in detail above. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0115] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0116] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A method for evaluating the cyclic adsorption performance of a carbon dioxide adsorbent, characterized by, The evaluation method comprises: S1, making the to-be-tested adsorbent in the thermal gravimetric analyzer to carry out impurity removal treatment and then carrying out multiple adsorption and desorption tests to obtain a thermal gravimetric cycle curve; S2. Calculate the regeneration rate H of the adsorbent in the i-th adsorption-desorption test according to formula 1 i in %: ; formula 1 E1is the weight percentage of the adsorbent after desorption of impurities in the first adsorption-desorption test, in wt%; Ei is the weight percentage of the adsorbent after desorption of CO2 in the i-th adsorption-desorption test, in wt%; and E is the weight percentage of the adsorbent after desorption of CO2 in the last adsorption-desorption test, in wt%. i E1is the weight percentage of the adsorbent after desorption of impurities in the first adsorption-desorption test, in wt%; Ei is the weight percentage of the adsorbent after desorption of CO2 in the i-th adsorption-desorption test, in wt%; and E is the weight percentage of the adsorbent after desorption of CO2 in the last adsorption-desorption The adsorption amount change rate I of the adsorbent in the i-th adsorption and desorption test is calculated according to Formula 2 i , unit: % ; formula 2 Wherein, F1 is the weight percentage of CO2 adsorbed by the adsorbent under test in the first adsorption-desorption test, in wt%; F i F is the weight percentage of CO2 adsorbed by the adsorbent under test in the i-th adsorption-desorption test, in wt%. S3, Regeneration rate H during all adsorption-desorption tests i The first data set is formed by combining the corresponding loop count i; the first data set is fitted to obtain the first fitted curve function H. i = f (i); the rate of change of adsorption amount I during all the adsorption-desorption tests i The second data set is formed by combining the corresponding loop count i; the second data set is then fitted to obtain the second fitted curve function I. i = f (i); S4. The method according to El, E i , Fl, F i , H2, I2, one or several of the first and second fitting curve functions to evaluate the performance of the adsorbent under test; The evaluation method further comprises calculating the limit cycle number x2 of the to-be-tested adsorbent when it is completely failed according to formula 4: ; Formula 4 The greater the value of x2 is, the longer the limit life of the to-be-tested adsorbent is; The i is a positive integer and i≥2.

2. The evaluation method according to claim 1, characterized by Step S4 further comprises: S41, evaluating the adsorbent stability of the to-be-tested adsorbent according to H2 and the first fitting curve function.

3. The evaluation method according to claim 1, characterized by, Step S4 further comprises: S42, evaluating the adsorption capacity stability of the to-be-tested adsorbent according to I2 and the second fitting curve function.

4. The evaluation method according to claim 3, characterized by Step S4 further comprises: S43. According to F1 and F i The adsorption amount of the adsorbent to be measured is evaluated.

5. The evaluation method according to claim 1, characterized by, The number of times of the adsorption and desorption tests is more than 5.

6. The evaluation method according to claim 1, characterized by The evaluation method further comprises: S5. Calculate the change J in the adsorption amount of the adsorbent in the two adjacent adsorption-desorption tests according to formula 3 i in wt%: ; formula 3 wherein F i-1 is the percentage by weight of CO2 adsorbed by the adsorbent in the i-1th adsorption-desorption test with respect to the weight of the adsorbent under test, i being a positive integer and i≥2; When the change amount J of the adsorption amount i <0 indicates that the adsorption performance of the adsorbent to be tested in the i-th adsorption and desorption test is improved than that in the i-1-th adsorption and desorption test. When the change amount J of the adsorption amount i > 0, it indicates that the adsorption performance of the adsorbent to be tested in the i-th adsorption and desorption test is lower than that in the (i-1)-th adsorption and desorption test.

7. The evaluation method according to claim 1, characterized by, The adsorption and desorption test comprises: making the adsorbent after impurity removal contact with CO2-rich gas at an adsorption temperature to carry out adsorption treatment until the weight of the adsorbent after impurity removal is stable, to obtain a carbon-rich adsorbent; making the carbon-rich adsorbent undergo regeneration treatment at a regeneration temperature until the weight of the carbon-rich adsorbent is stable, to obtain a regenerated adsorbent.

8. The evaluation method according to claim 1, characterized by, The evaluation method further comprises rounding the limit cycle number x2 to obtain the maximum cycle number M of the to-be-tested adsorbent; the greater the value of the maximum cycle number M is, the greater the maximum cycle number of the to-be-tested adsorbent is.

9. Application of the evaluation method in any one of claims 1-8 in the field of carbon dioxide adsorption.

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