Method for selecting high-concentration VOCs adsorbent at different temperatures and application

Abstract

The invention provides a method for selecting a high-concentration VOCs adsorbent at different temperatures and application, and belongs to the technical field of waste gas governing. According to the method, through testing pore structure parameters of a model adsorption material with concentrated pore size distribution, a static adsorption isotherm and a dynamic penetration curve for VOCs at different temperatures, a high-concentration VOCs adsorbent is obtained; a linear relation equation of the critical aperture and the critical pressure is established through linear fitting, then a correlation equation of the critical aperture, the temperature and the partial pressure is established, and the appropriate aperture distribution range and the model selection standard of the high-concentration VOCs adsorbent at different temperatures are determined by combining dynamic adsorption results. According to the method, the ternary matching relation equation of the VOCs partial pressure, the temperature and the critical aperture is constructed, accurate type selection of the high-concentration VOCs adsorbent at different temperatures is achieved, the pore volume utilization rate and the adsorption capacity can be improved, meanwhile, desorption energy consumption and the VOCs pyrolysis risk are reduced, and a theoretical basis is provided for adsorbent type selection and technical optimization.

Description

Technical Field

[0001] This invention relates to the field of waste gas treatment technology, and in particular to a method and application for selecting high-concentration VOCs adsorbents at different temperatures. Background Technology

[0002] Volatile organic compounds (VOCs), as a key class of air pollutants, are not only a major contributing factor to environmental problems such as smog, ozone pollution, and photochemical smog, but also directly or indirectly harm human health. Therefore, VOCs control has become one of the core tasks of current air pollution control. Among VOCs end-of-pipe treatment technologies, adsorption has become one of the most widely used technologies due to its simple operation, high purification efficiency, wide applicability, ease of integration with other technologies, and potential for carbon reduction.

[0003] However, the effectiveness of the adsorption process is affected by a variety of factors, including the structural properties of the adsorbent (such as pore size, specific surface area, pore volume, etc.), the physicochemical properties of the adsorbate (such as saturated vapor pressure, boiling point, etc.), and the adsorption process conditions (such as temperature, partial pressure, etc.). The interaction of these factors is essentially a matching relationship between the adsorbent and the adsorbate under specific conditions, among which the influence of pore structure is particularly critical.

[0004] High-concentration VOCs are emitted in numerous industrial settings, including chemical, pharmaceutical, petrochemical, and paper coating industries. Examples include VOCs carried by nitrogen protective gas in pharmaceutical intermediate production, near-saturated vapor pressure exhaust from organic solvent storage tanks, high-volatility VOCs in continuous exhaust from reactors, and high-concentration VOCs volatilized during the heating phase of coating processes. In these scenarios, nitrogen is often used instead of air as a protective gas to create a low-oxygen or oxygen-free environment for the exhaust gases, meeting the explosion limit requirements of adsorption and recovery technologies. Therefore, developing specialized adsorbents and quantitative selection methods for such high-concentration VOCs has become an important direction for the development of VOCs control materials and technologies.

[0005] Currently, adsorbent selection largely relies on trial and error, determining the optimal adsorbent by testing the dynamic adsorption performance of different candidates, which is inefficient. Meanwhile, the industry's understanding of pore structures is limited: micropores exhibit advantages in adsorption due to their strong adsorption potential, but desorption is difficult and energy-intensive; mesopores, while having larger pore volumes and being easier to increase, are considered unsuitable for stable VOC adsorption due to their weaker adsorption potential, and their potential value has not been fully explored. In fact, the "appropriateness" of the adsorption force is crucial—it needs to be strong enough to ensure adsorption efficiency, but also avoids excessive strength that could lead to desorption problems (such as VOC pyrolysis, pore blockage, and complex recovery components). Therefore, providing a suitable adsorption force, i.e., providing sufficient adsorption force while avoiding excessive strength, is key to solving the above problems.

[0006] Further research (J. Am. Chem. Soc. 2024, 146, 49, 33434-33442) indicates that the adsorption of gases by solid adsorbent materials involves two mechanisms: "filling adsorption" and "covering adsorption." Filling adsorption, based on volumetric filling, achieves high pore volume utilization for VOCs, and its occurrence depends on whether the pore size is smaller than a specific "critical pore size." Covering adsorption refers to the adsorption mechanism where adsorbate molecules form a single or multiple layer covering on the adsorbent surface, resulting in lower pore volume utilization. Comparatively, filling adsorption offers significantly higher pore volume utilization than covering adsorption. Therefore, the occurrence of filling adsorption plays a decisive role in the pore volume utilization and adsorption capacity of the adsorbent material. However, current research has not fully considered temperature factors in understanding this critical pore size, nor has it revealed the synergistic effects of adsorbent, adsorbate, and process conditions at different temperatures, making it impossible to achieve efficient filling adsorption in mesopores through temperature control.

[0007] Existing technologies, such as invention patents with patent numbers 202410699302.6 and 202310610575.4, and journal articles (J.Am.Chem.Soc.2024,146,49,33434-33442), provide some methods for selecting VOCs adsorbents, but they do not address the influence of temperature on the critical pore size of packed adsorption and cannot provide a quantitative reference for selecting adsorbents for high concentrations of VOCs at different temperatures.

[0008] Therefore, developing a quantitative adsorbent selection method that can adapt to different adsorption temperature conditions and is suitable for high-concentration VOCs is of great significance for overcoming the limitations of traditional trial-and-error methods, giving full play to the advantages of mesoporous materials, improving adsorption and recovery efficiency, and reducing desorption energy consumption. Summary of the Invention

[0009] To overcome the shortcomings of existing technologies, the purpose of this invention is to provide a method and application for selecting high-concentration VOCs adsorbents at different temperatures. By constructing a ternary matching equation of VOCs partial pressure, temperature and critical pore size, the method enables precise selection of high-concentration VOCs adsorbents at different temperatures. This method can improve pore volume utilization and adsorption capacity while reducing desorption energy consumption and VOCs pyrolysis risk, providing a theoretical basis for adsorbent selection and technology optimization.

[0010] To achieve the above objectives, the present invention provides the following solution:

[0011] A method for selecting high-concentration VOCs adsorbents at different temperatures includes the following steps:

[0012] S1. Select two or more porous materials with concentrated pore size distribution as model adsorption materials and test their pore structure parameters.

[0013] S2. Test the static adsorption isotherms of the model adsorbent material for VOCs at different temperatures, determine the critical pressure corresponding to the packed adsorption, and establish the linear relationship equation between the critical pore size and the critical pressure through linear fitting:

[0014] D C =k×P C +D0;

[0015] In the formula, D C Critical pressure P C The critical pore size at which packed adsorption can occur, P C For an aperture size of D C The critical pressure required for packed adsorption to occur is given by k, where k is the slope of the linear relationship between the critical pore size and the critical pressure, and D0 is the critical pore size D when the pressure approaches 0 in the linear relationship. C The value;

[0016] S3. Based on the aforementioned linear relationship equation, determine the variation law of critical pore size with adsorption temperature under the same partial pressure, construct the correlation equation between critical pore size and temperature and partial pressure, and form an adsorbent selection method suitable for high concentrations of VOCs at different temperatures; the correlation equation is:

[0017] D C =f(T)×P C +D0;

[0018] In the formula, D C P represents the critical pore size at different adsorption temperatures T under the same partial pressure, corresponding to the conditions for packed adsorption. C For an aperture size of D C The critical pressure required for packed adsorption to occur is given by k = f(T), which represents the slope of the linear relationship between the critical pore size and the critical pressure. k is a function of temperature T.

[0019] S4. Test the dynamic adsorption breakthrough curve of the model adsorbent material for a certain concentration of VOCs at different temperatures, calculate the dynamic breakthrough and saturation adsorption amount, and obtain the dynamic adsorption results.

[0020] S5. Based on the dynamic adsorption results and in conjunction with the above selection method, determine the appropriate pore size distribution range and selection criteria for high-concentration VOCs adsorbents at different temperatures.

[0021] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0022] (1) This invention analyzes the differences in the mechanisms of packed and covered adsorption, using the critical pore size D CThis allows for precise selection of adsorbents for high-concentration VOCs based on key parameters. It clarifies that packed adsorption only occurs when the pore size is smaller than the critical pore size D. C In the pores, and with a pore volume utilization rate much higher than that of covered adsorption, the precise control of the critical pore size becomes the key to improving adsorption performance, and provides a clear indicator for adsorbent screening.

[0023] (2) This invention establishes the critical aperture D C The dynamic matching relationship between VOCs partial pressure and adsorption temperature: The critical pore size increases as the adsorption temperature decreases. This pattern transforms mesoporous materials, which are normally difficult to fill with adsorption, into highly efficient adsorption spaces at low temperatures. By screening mesoporous materials with pore sizes concentrated in the range smaller than and close to the critical pore size, we can leverage their high pore volume to increase adsorption capacity while avoiding desorption problems caused by excessively strong micropore adsorption potential. This improves pore volume utilization while reducing desorption energy consumption and the risk of VOCs pyrolysis.

[0024] (3) This invention selects two or more mesoporous adsorption materials, tests their pore structure parameters and static adsorption isotherms of target VOCs at different temperatures, explores the correlation between critical pore size and partial pressure and temperature by combining the controlled variable method and establishes a ternary matching equation, and integrates the influence data of temperature on saturated adsorption capacity and pore volume utilization rate in dynamic adsorption experiments. By adjusting the adsorption temperature and screening adsorbents with suitable pore sizes, the critical pore size range can be maximized within an economically reasonable temperature range, balancing adsorption efficiency and desorption energy consumption.

[0025] (4) This invention has significant application value. It not only provides a quantitative pore size reference for the selection of high-concentration VOCs adsorbents, but also constructs a synergistic optimization framework for VOCs partial pressure, adsorbent pore size, and temperature, providing new ideas for the directional design of efficient adsorption materials and the optimization of adsorption-desorption process parameters in industrial scenarios. Its promotion will accelerate the large-scale application of mesoporous materials in VOCs treatment, promote the upgrading of adsorption and recovery technology towards low energy consumption and high resource utilization, and help the industrial sector achieve the synergistic advancement of VOCs emission reduction and "dual carbon" goals. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram illustrating the method for selecting high-concentration VOCs adsorbents at different temperatures in this invention.

[0028] Figure 2The image shows the pore size distribution of the model adsorbent materials MCM-3.0, MCM-4.0, and MCM-4.5 in Example 1 of this invention.

[0029] Figure 3 The static adsorption isotherms of ethyl acetate by MCM-3.0, MCM-4.0, and MCM-4.5 at multiple adsorption temperatures are shown in Example 1 of this invention.

[0030] Figure 4 The critical pressure P for the packed adsorption of ethyl acetate by each model adsorbent at multiple temperatures in Example 1 of this invention is given. C With critical aperture D C Linear relationship graph;

[0031] Figure 5 For the adsorption of ethyl acetate in Example 1 of this invention, the critical pressure P for forming a packed adsorption is determined. C With critical aperture D C Matching relation equation D C =k×P C In +D0, the graph shows the relationship between slope k and temperature T.

[0032] Figure 6 This is the static adsorption isotherm of ethyl acetate by MCM-4.5 in Example 1 of this invention;

[0033] Figure 7 In Embodiment 1 of the present invention, the critical pore size D that enables the formation of packed adsorption is calculated based on the ternary matching relationship of critical pore size, partial pressure, and temperature under the same partial pressure. C A comparison diagram of the pore size positions with those of the adsorbent material MCM-4.5;

[0034] Figure 8 This is a dynamic adsorption breakthrough curve of the MCM-4.5 material in Example 2 of the present invention for ethyl acetate-containing waste gas with a partial pressure of 30 mbar at multiple temperatures;

[0035] Figure 9 This is a comparison of the dynamic saturation and dynamic breakthrough adsorption capacity of MCM-4.5 with pore sizes mainly distributed between 4.0-6.0 nm in Example 2 of the present invention for adsorbing ethyl acetate-containing waste gas at a partial pressure of 30 mbar at different adsorption temperatures.

[0036] Figure 10 This is a comparison chart of the dynamic saturated adsorption capacity and dynamic breakthrough adsorption capacity per unit pore volume of MCM-4.5 for adsorbing ethyl acetate-containing waste gas with a partial pressure of 30 mbar at multiple adsorption temperatures in Example 2 of the present invention.

[0037] Figure 11The static adsorption isotherms of MCM-3.0, MCM-4.0, and MCM-4.5 for benzene at multiple adsorption temperatures are shown in Example 3 of this invention.

[0038] Figure 12 The critical pressure P for packed adsorption of benzene at multiple adsorption temperatures in Example 3 of this invention is... C With critical aperture D C Linear relationship graph;

[0039] Figure 13 The critical pressure P for packed adsorption during the benzene adsorption process in Example 3 of this invention is... C With critical aperture D C Matching relation equation D C =k×P C In +D0, the graph shows the relationship between slope k and temperature T.

[0040] Figure 14 This is the static adsorption isotherm of MCM-4.5 for benzene under the same pressure in Example 3 of the present invention;

[0041] Figure 15 In Example 3 of this invention, during the adsorption of benzene under the same pressure, the critical pore size D that enables the formation of a packed adsorption structure was calculated based on the ternary matching relationship of critical pore size, partial pressure, and temperature. C A comparison diagram of the pore size positions with those of the adsorbent material MCM-4.5;

[0042] Figure 16 This is a dynamic adsorption breakthrough curve of the MCM-4.5 material in Example 3 of the present invention for benzene-containing waste gas with a partial pressure of 30 mbar at multiple temperatures;

[0043] Figure 17 The dynamic saturated adsorption capacity and dynamic breakthrough adsorption capacity of MCM-4.5 with pore size mainly distributed between 4.0-6.0 nm in Example 3 of the present invention for the adsorption of benzene-containing waste gas with a partial pressure of 30 mbar under different adsorption conditions;

[0044] Figure 18 The adsorption capacity per unit pore volume of MCM-4.5, whose pore size is mainly distributed between 4.0-6.0 nm in Example 3 of the present invention, is measured under different adsorption conditions for the adsorption of benzene-containing waste gas with a partial pressure of 30 mbar.

[0045] Figure 19 This is a dynamic adsorption breakthrough curve of the MCM-4.0 material in Example 4 of the present invention for benzene-containing waste gas with a partial pressure of 30 mbar at multiple temperatures;

[0046] Figure 20In Example 4 of this invention, during the adsorption of benzene under the same pressure, the critical pore size D that enables the formation of a packed adsorption structure was calculated based on the ternary matching relationship of critical pore size, partial pressure, and temperature. C A comparison diagram of the pore size positions with those of the adsorbent material MCM-4.0;

[0047] Figure 21 The pore volume utilization rate of MCM-4.0, whose pore size is mainly distributed between 3.5-4.5 nm, for the adsorption of benzene-containing waste gas with a partial pressure of 30 mbar under different adsorption conditions in Example 4 of the present invention;

[0048] Figure 22 This is a verification diagram of the cyclic adsorption stability and low-energy desorption performance of MCM-4.0 in the treatment of benzene-containing waste gas in Example 4 of the present invention; wherein, Figure 22 (a) shows the dynamic breakthrough adsorption test results of MCM-4.0 material with pore sizes mainly distributed between 3.5-4.5 nm at 5 °C for 5 cycles of benzene-containing waste gas with a partial pressure of 30 mbar. Figure 22 (b) in the figure shows the desorption performance curves at different temperatures (30–70 °C);

[0049] Figure 23 The static adsorption isotherms of acetone on MCM-3.0, MCM-4.0, and MCM-4.5 materials at different adsorption temperatures are shown in Example 5 of this invention.

[0050] Figure 24 In the acetone adsorption of Example 5 of the present invention, the critical pressure P for packed adsorption is... C With critical aperture D C The matching relationship and the matching relationship equation D C =k×P C In +D0, the graph shows the relationship between slope k and temperature T.

[0051] Figure 25 In Example 5 of this invention, the critical pore size D for forming a packed adsorption at multiple adsorption temperatures was calculated during the adsorption of acetone under the same pressure. C A comparison diagram of the pore size of the adsorbent material MCM-4.0 and a dynamic breakthrough curve of the adsorbent material MCM-4.0 at multiple adsorption temperatures. Detailed Implementation

[0052] 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 only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] 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.

[0054] like Figure 1 As shown, this invention provides a method for selecting high-concentration VOCs adsorbents at different temperatures, comprising the following steps:

[0055] S1. Select two or more porous materials with concentrated pore size distribution as model adsorption materials and test their pore structure parameters.

[0056] In step S1, the pore structure parameters include pore size distribution, pore volume, and specific surface area, which are obtained through DFT cylindrical pore calculation model testing. The model adsorbent material is one or more of ordered mesoporous carbon, ordered mesoporous silica, or molecular sieves, and the pore size distribution is within the range of micropores and small mesopores.

[0057] S2. Test the static adsorption isotherms of the model adsorbent material for VOCs at different temperatures, determine the critical pressure corresponding to the packed adsorption, and establish the linear relationship equation between the critical pore size and the critical pressure through linear fitting:

[0058] D C =k×P C +D0; (1)

[0059] In the formula, D C Critical pressure P C The critical pore size at which packed adsorption can occur, expressed in nm (P). C For an aperture size of D C The critical pressure required for packed adsorption to occur is given by k (mbar), the slope of the linear relationship between critical pore size and critical pressure is given by k (nm / mbar), and D0 is the critical pore size D when the pressure approaches 0 in the linear relationship. C The value is expressed in nm.

[0060] In step S2, the critical pressure P C This represents the midpoint of the pressure range corresponding to the rapid increase in adsorption amount during the static adsorption isotherm.

[0061] S3. Based on the aforementioned linear relationship equation, determine the variation law of critical pore size with adsorption temperature under the same partial pressure, construct the correlation equation between critical pore size and temperature and partial pressure, and form an adsorbent selection method suitable for high concentrations of VOCs at different temperatures; the correlation equation is:

[0062] D C =f(T)×P C +D0; (2)

[0063] In the formula, D C P represents the critical pore size at different adsorption temperatures T under the same partial pressure, corresponding to the conditions for packed adsorption. C For an aperture size of D C The critical pressure required for packed adsorption to occur is given by k = f(T), which represents the slope of the linear relationship between the critical pore size and the critical pressure. k is a function of temperature T.

[0064] S4. Test the dynamic adsorption breakthrough curve of the model adsorbent material for a certain concentration of VOCs at different temperatures, calculate the dynamic breakthrough and saturation adsorption amount, and obtain the dynamic adsorption results.

[0065] The dynamic breakthrough and saturation adsorption capacity are calculated using the following formula:

[0066]

[0067] Where Q is the dynamic breakthrough adsorption amount Q dp Or dynamic saturated adsorption capacity Q ds F is the total gas flow rate, M is the molar mass of the adsorbate, and V is the total gas flow rate. m The value is the molar volume of gas under standard conditions, taken as 22.4 L / mol, where m is the net weight of the adsorbent, c0 is the initial VOCs concentration at the inlet of the adsorbent bed, and c i t represents the VOCs concentration at the outlet of the adsorbent bed;

[0068] Calculate the dynamic breakthrough adsorption capacity Q dp At that time, the outlet concentration c i =5% × c0, corresponding to the penetration time t dp The time taken for the VOCs concentration at the outlet of the adsorbent bed to reach 5% of the inlet concentration;

[0069] Calculate the dynamic saturated adsorption capacity Q ds At that time, the outlet concentration c i =c0, corresponding to the saturation time t ds This is the time required for the adsorbent bed outlet concentration to be the same as the inlet concentration.

[0070] S5. Based on the dynamic adsorption results and in conjunction with the above selection method, determine the suitable pore size distribution range and selection criteria for high-concentration VOCs adsorbents at different temperatures. That is, the pore size distribution of the adsorbent should be concentrated in a range smaller than and close to the critical pore size D at the corresponding temperature and partial pressure. C Within the range.

[0071] The above-mentioned method for selecting high-concentration VOCs adsorbents at different temperatures is particularly applicable to high-concentration VOCs waste gas treatment scenarios in the chemical, pharmaceutical, and petrochemical industries.

[0072] The following examples illustrate in detail the method for selecting high-concentration VOCs adsorbents applicable to different temperatures provided by the present invention.

[0073] Example 1

[0074] A series of ordered mesoporous silica MCM-41 materials with concentrated pore size distributions were used as model adsorbents, named MCM-3.0, MCM-4.0, and MCM-4.5, respectively. The pore size distribution of the materials was obtained using a commercial pore structure and specific surface area analyzer via a DFT cylindrical pore calculation model. The results are shown below. Figure 2 As shown, the pore size distribution is concentrated at 3.0 nm, 4.0 nm, and 4.5 nm, respectively.

[0075] The static adsorption capacity of three model adsorbents for ethyl acetate at 5℃, 15℃, 25℃, 35℃, and 45℃ was tested using an intelligent gravimetric analyzer (IGA), and static adsorption isotherms were obtained, such as... Figure 3 As shown. In this embodiment, the static adsorption of ethyl acetate on the concentrated pore size MCM-41 material is a typical type IV isotherm, divided into three stages: In the initial stage, as the pressure increases, the adsorption amount rises slowly during the plateau period, which is a monolayer or multilayer covering adsorption on the mesoporous surface; in the intermediate stage, the adsorption amount rises rapidly, caused by capillary condensation in the concentrated pores, i.e., filling adsorption; in the third stage, the isotherm reaches the second plateau period, and the adsorption amount increases slowly, due to the rearrangement of ethyl acetate molecules in the mesopores under pressure.

[0076] Based on the static adsorption isotherm, the pressure range corresponding to the filling adsorption of each model adsorbent material is determined. The median value of the pressure range corresponding to the rapid rise phase of the static adsorption isotherm is defined as the critical pressure P of filling adsorption. C At adsorption temperatures of 5℃, 15℃, 25℃, 35℃, and 45℃, the pressure P corresponding to the midpoint of the rapid rise phase in the adsorption isotherms of the model adsorbents MCM-3.0, MCM-4.0, and MCM-4.5 is... CAs shown in Table 1, it can be observed that at the same adsorption temperature, the larger the pore size of the adsorbent material, the greater the pressure required for the filling adsorption to occur, and there is a correlation between the pressure and the corresponding critical pore size.

[0077] Table 1 shows the pressures (in mbar) corresponding to the midpoints of the rapid rise phases in the adsorption isotherms of ethyl acetate by the model adsorbent material at different temperatures.

[0078] Material aperture 5℃ 15℃ 25℃ 35℃ 45℃ MCM-3.0 3.0nm 3.8 6.7 12.2 21.3 34.7 MCM-4.0 4.0nm 7.2 13.3 24.3 40.7 68.0 MCM-4.5 4.5nm 10.2 18.6 33.2 56.8 92.7

[0079] The critical pressure P of three model adsorbent materials with different pore sizes was determined at the same adsorption temperature. C By performing linear fitting with the pore size of each material, the critical pressure P for the packed adsorption of ethyl acetate by the model adsorbent at various temperatures was obtained. C With critical aperture D C Linear relationship, such as Figure 4 As shown. According to equation (1), the adsorption of ethyl acetate at multiple temperatures and the critical pressure P required to form a packed adsorption are obtained. C and critical aperture D C The linear relationship equation between them is:

[0080] At 5℃, D C =0.235×P C +2.13nm;

[0081] At 15℃, D C =0.133×P C +2.10nm;

[0082] At 25℃, D C =0.075×P C +2.06nm;

[0083] At 35℃, D C =0.044×P C +2.05nm;

[0084] At 45℃, D C =0.027×P C +2.03nm.

[0085] Based on the critical pore size and critical pressure P of VOCs in the packed adsorption at multiple adsorption temperatures obtained above... C The linear relationship was used to calculate the critical pore size D for packed adsorption under the same partial pressure. C The relationship between adsorption temperature T and the slope k of the linear equation obtained at five temperatures was fitted relative to temperature T, as follows: Figure 5As shown, the equation relating slope k to temperature T is obtained:

[0086] k=0.31×exp(-T / 16.9)+0.005; (4)

[0087] Substituting equation (4) into equation (1), we obtain the equation showing the trend of critical pore size with partial pressure and adsorption temperature T: D C =(0.31×exp(-T / 16.9)+0.005)×P C +D0; By comparison, it was found that the intercept D0 of the linear equation obtained at the five temperatures did not change significantly with the adsorption temperature. Therefore, the average value of D0 at the five temperatures, 2.1 nm, can be taken as the D0 value of the above equation. The critical pore size D is obtained. C With the partial pressure P C The equation for the trend of adsorption temperature T:

[0088] D C =(0.31×exp(-T / 16.9)+0.005)×P C +2.1; (5)

[0089] Furthermore, equation (5) represents the VOCs partial pressure (P), adsorption temperature (T), and critical pore size (D) constructed in this embodiment. C The ternary matching core equation is a direct tool for quantitatively selecting adsorbents for high concentrations of VOCs at different temperatures. Based on this equation, the adsorbent for a specific pressure P can be obtained. C At that time, the critical pore size D corresponding to multiple adsorption temperatures T that allows for packed adsorption is... C This clarifies that under the target operating conditions, an aperture smaller than and close to that D should be selected. C The adsorbent with a specific value. By using the ternary matching relationship of critical pore size, partial pressure and temperature in equation (5), the pressure required for a specific pore size to undergo filling adsorption at a specific adsorption temperature was calculated, and the results are shown in Table 2.

[0090] Table 2. Pressure required for packed adsorption to occur at specific adsorption temperatures and for specific pore sizes.

[0091]

[0092]

[0093] Table 2 shows that as the adsorption temperature increases and the pore size of the adsorbent material increases, the critical pressure P of packed adsorption in the static adsorption isotherm decreases. CBoth the pressure required to reach static adsorption saturation and the pressure required to achieve this state increase significantly. At lower temperatures (5°C), pore sizes of 3.0, 4.0, and 4.5 nm achieve packed adsorption at pressures of 3.8 mbar, 8.1 mbar, and 10.2 mbar, respectively; however, when the temperature increases to 45°C, the pressures required to achieve packed adsorption increase to 33.8 mbar, 71.4 mbar, and 90.1 mbar, respectively. For the same pore size, the critical pressure P for packed adsorption in the static adsorption isotherm increases with increasing adsorption temperature. C All showed an increasing trend. For example, for a pore with a diameter of 3.0 nm, the critical pressure P at temperatures of 5℃, 15℃, 25℃, 35℃, and 45℃... C The specific values ​​are 3.8, 6.8, 11.9, 20.4, and 33.8 mbar, respectively. This means that by lowering the adsorption temperature, pores of a specific size can form a packed adsorption system with high pore volume utilization at a lower partial pressure.

[0094] like Figure 6 As shown, under the same pressure conditions, the adsorption capacity at lower adsorption temperatures is significantly higher than that at room temperature and higher temperatures. For example, taking the adsorption of ethyl acetate by MCM-4.5 at 30 mbar as an example, the static adsorption isotherms at 5℃ and 15℃ show that packed adsorption has been completed. At 25℃, only some pore sizes form packed adsorption; while at 35℃ and 45℃, no packed adsorption is formed, and the adsorption capacity is less than half of that required for packed adsorption. Therefore, by lowering the adsorption temperature, it is possible to achieve packed adsorption with high pore volume utilization at lower partial pressures for pores of specific sizes.

[0095] Based on equation (5), the critical pore size D for ethyl acetate to undergo packed adsorption at different partial pressures and adsorption temperatures can be calculated. C For example, at a partial pressure of 30 mbar, the critical pore sizes for packed adsorption at multiple adsorption temperatures (5, 15, 25, 35, 45 °C) are 9.2, 6.1, 4.4, 3.4, and 2.9 nm, respectively, as shown in Table 3. Figure 7 As shown. By comparing the static adsorption capacity at 30 mbar pressure under conditions of 5℃, 15℃ and 35℃, 45℃, it can be seen that appropriately lowering the temperature can fully utilize the pore volume of larger pores (such as mesopores) to form a packed adsorption with high pore volume utilization.

[0096] Table 3 shows the critical pore size D for packed adsorption when the partial pressure of ethyl acetate is 30 mbar, calculated according to equation (5). C Corresponding values ​​between adsorption temperature T

[0097] T(℃) P(mbar) <![CDATA[P0]]> k value <![CDATA[D C ]]> 5 30 43.1 0.236 9.2 15 30 74.9 0.133 6.1 25 30 124.5 0.076 4.4 35 30 199.0 0.044 3.4 45 30 306.9 0.027 2.9

[0098] Where P0 is the saturated vapor pressure of ethyl acetate at the corresponding temperature (unit: mbar). This embodiment reveals the relationship between the critical pore size for packed adsorption and the adsorption temperature by testing the static adsorption isotherms of ethyl acetate using model adsorbents (MCM-3.0, MCM-4.0, and MCM-4.5) at multiple adsorption temperatures, constructing a relationship between VOCs partial pressure, adsorbent pore size, and adsorption temperature (PTD). C The ternary matching equation was used to establish a complete method for selecting high-concentration VOCs adsorbents at different temperatures. This method takes the ternary matching equation as its core and combines the correlation between critical pressure and pore size to form a complete selection system from theoretical derivation to experimental verification.

[0099] Example 2

[0100] Based on the adsorption selection method provided in Example 1, to verify the practicality of the adsorbent selection method provided in Example 1, a fixed-bed adsorption device coupled with gas chromatography was used to test the dynamic adsorption results of the adsorbent material for VOCs at multiple adsorption temperatures. By applying the adsorbent selection method of the present invention to a dynamic adsorption process, the applicability and scalability of the method in actual working conditions were verified, providing a basis for the engineering application of the selection method.

[0101] Taking MCM-4.5 material as an example, the dynamic adsorption breakthrough curves of MCM-4.5 material for ethyl acetate at corresponding adsorption temperatures (5, 15, 25, 35, 45℃) are shown below. Figure 8 As shown in Table 4. Test conditions: flow rate of 20 ml / min, adsorbent dosage of 0.3 g. Based on the time of the dynamic adsorption breakthrough curve, combined with the exhaust gas flow rate, VOCs concentration and adsorbent dosage, the dynamic breakthrough adsorption capacity and dynamic saturation adsorption capacity of VOCs at a specific concentration are calculated, as shown in Table 4. The calculation formulas for the dynamic breakthrough and saturation adsorption capacity of VOCs are referred to formula (3).

[0102] Table 4. Dynamic saturated adsorption capacity (Q) of adsorbent MCM-4.5 for ethyl acetate-containing waste gas at a partial pressure of 30 mbar at multiple adsorption temperatures. ds ) and dynamic breakthrough adsorption capacity (Q) dp )

[0103]

[0104] The total pore volume of MCM-4.5 material is 0.802 cm³. 3The adsorption of ethyl acetate-containing waste gas at a partial pressure of 30 mbar by MCM-4.5 at multiple temperatures, and the dynamic saturation adsorption capacity and dynamic breakthrough adsorption capacity of ethyl acetate-containing waste gas at a partial pressure of 30 mbar at multiple adsorption temperatures are shown in Table 4. Figure 9 As shown, the adsorption capacity per unit pore volume is as shown in Table 4 and Figure 10 As shown.

[0105] Based on the above, it can be found that for organic waste gas with an ethyl acetate partial pressure of 30 mbar, as the adsorption temperature increases from 5℃ to 45℃, the calculated upper limit of the suitable pore size of the adsorbent material (i.e., the critical pore size D) increases. C The pore size decreased from 9.2 nm to 2.9 nm. MCM-4.5 material with a pore size distribution of 4.0-6.0 nm met the requirements at 5℃ and 15℃, achieving filled adsorption with a high adsorption capacity per unit pore volume; at 25℃, only about half of the pores could achieve filled adsorption, and the adsorption capacity decreased; at 35℃ and 45℃, due to the pore size exceeding the limit, mainly covered adsorption occurred, and the adsorption capacity was significantly reduced, thus verifying the rationality of the selection method and its guiding significance for different temperature conditions.

[0106] Based on the above, the ternary matching equation between VOCs partial pressure, adsorbent pore size, and adsorption temperature constructed in Example 1 can determine the appropriate pore size range according to specific emissions, providing a quantitative tool for the precise selection of high-concentration VOCs adsorbents at different temperatures. By configuring adsorbent materials with suitable pore size ranges, high-pore-volume utilization of packed adsorption can be achieved by controlling the adsorption temperature, resulting in the formation of high-pore-volume utilization in larger pores. Furthermore, it is revealed that this equation is also applicable to dynamic adsorption processes, demonstrating the reliability of this selection method in practical applications and providing direct technical support for adsorbent screening in industrial scenarios.

[0107] Example 3

[0108] This embodiment uses benzene as the target pollutant to verify the applicability of this selection method to different VOCs. Using the ordered mesoporous silica MCM-41 materials with concentrated pore size distribution from Example 1 above as model adsorbents, the static adsorption capacity of three model adsorbents for benzene at 5℃, 15℃, 25℃, 35℃, and 45℃ was tested using an intelligent gravimetric analyzer (IGA), and the static adsorption isotherms were obtained as follows: Figure 11 As shown.

[0110] Using the method of Example 1, the pressures corresponding to the midpoints of the rapid rise phases in the adsorption isotherms of benzene by the model adsorbent material at multiple temperatures are shown in Table 5.

[0111] Table 5 shows the pressures (P) corresponding to the midpoints of the rapid rise phases in the adsorption isotherms of benzene by the model adsorbent material at different temperatures.C Unit: mbar

[0112]

[0113] Using the method provided in Example 1, and according to Figure 12 The critical pore size and critical pressure P of the packed adsorption of VOCs at multiple adsorption temperatures were obtained. C The linear relationship, combined with equation (2), yields the critical pore size D for benzene adsorption under the same partial pressure, which is required for packed adsorption. C The relationship between slope k and adsorption temperature T is investigated. By fitting the slope k of the linear equation obtained at five temperatures relative to temperature T, a regular equation showing the relationship between slope k and temperature T is obtained, as follows: Figure 13 As shown. k = 0.32 × exp(-T / 17.7) + 0.009. Substituting this equation into D... C =k×P C In D0, we obtain the equation showing the trend of critical pore size with partial pressure P and adsorption temperature T during the adsorption of benzene: D C = (0.32×exp(-T / 17.7)+0.009)×P+D0. By comparison, it was found that the intercept D0 of the linear equation obtained at the five temperatures did not change significantly with the adsorption temperature. Therefore, the average value of D0 at the five temperatures, 1.8 nm, can be taken as the D0 value of the above equation. The equation showing the trend of critical pore size with partial pressure P and adsorption temperature T is obtained as follows:

[0114] D C =(0.32×exp(-T / 17.7)+0.009)×P C +1.8; (6)

[0115] Based on this equation, the critical pore size D corresponding to multiple adsorption temperatures T at a specific pressure P can be obtained for the occurrence of packed adsorption. C This provides a direct basis for the selection of benzene adsorbents. Based on this equation, the critical pore size, critical partial pressure, critical temperature, and matching relationship among these three parameters required for high pore volume utilization in packed adsorption can be obtained. Equation (6) allows us to obtain the critical pore size D at a specific adsorption temperature T. C The corresponding critical pressure P that enables packed adsorption C This allows us to determine whether an adsorbent with a specific pore size is suitable for benzene adsorption. Based on the ternary matching relationship of critical pore size, partial pressure, and temperature in equation (6), the pressure required for a specific pore size to undergo packed adsorption at a specific adsorption temperature can be derived, as shown in Table 6.

[0116] Table 6. Pressure required for packed adsorption to occur at specific adsorption temperatures and for specific pore sizes.

[0117]

[0118] As shown in Table 6, with the decrease of adsorption temperature and the reduction of pore size of the adsorbent material, the critical pressure P of packed adsorption in the static adsorption isotherm decreases. C Both the pressure required to reach static adsorption saturation and the pressure required to achieve this state were significantly reduced.

[0119] According to equation (6), when the adsorption temperature is 45℃, the pressures corresponding to the filling adsorption of pores with 3.0nm, 4.0nm and 4.5nm are 35.1mbar, 64.4mbar and 79.0mbar respectively. At a lower temperature (5℃), pores with 3.0nm, 4.0nm and 4.5nm can form filling adsorption with high pore volume utilization at 4.8mbar, 8.8mbar and 10.8mbar respectively. This indicates that at low temperatures, adsorbents with larger pore sizes can be used to treat low partial pressure benzene waste gas.

[0120] For the same pore size, as the adsorption temperature decreases, the critical pressure P of packed adsorption in the static adsorption isotherm decreases. C All showed a decreasing trend. For example, according to equation (6), for a pore with a diameter of 3.0 nm, the critical pressure P at temperatures of 5℃, 15℃, 25℃, 35℃, and 45℃ is calculated to be... C The values ​​are 4.8, 8.2, 13.8, 22.5, and 35.1 mbar, respectively. By lowering the adsorption temperature, pores of specific sizes can form a packed adsorption with high pore volume utilization at a lower partial pressure, which provides a basis for the temperature-adaptive selection of benzene waste gas adsorbents.

[0121] Under the same pressure conditions, the static adsorption capacity at lower temperatures is significantly higher than that at higher temperatures. For example, taking the static adsorption of benzene by MCM-4.5 at 30 mbar as an example... Figure 14 As shown, according to equation (6), the static adsorption isotherms at 5℃ and 15℃ have reached saturation, while at 25℃, the adsorption capacity is still in a rapid increase phase and is still some distance from the saturated adsorption capacity; while at 35℃ and 45℃, the static adsorption capacity is only about one-third of the saturated adsorption capacity. Therefore, by lowering the adsorption temperature, pores of a specific size can form a packed adsorption with high pore volume utilization at a lower partial pressure, verifying the effectiveness of the low-temperature selection strategy for benzene adsorption.

[0122] By comparing the static adsorption capacity at 5℃, 15℃ and 35℃, 45℃ under 30mbar pressure, it can be seen that appropriately lowering the temperature can promote the formation of high-pore-volume-utilization packed adsorption in larger pores, verifying the effectiveness of the adsorbent selection method of this invention for benzene adsorption in benzene waste gas treatment. Additionally, as... Figure 15 As shown in Table 7, for organic waste gas with a benzene partial pressure of 30 mbar, the suitable pore size of the adsorption material should be less than 9.3 nm, 6.2 nm, 4.4 nm, 3.4 nm, and 2.8 nm at adsorption temperatures of 5℃, 15℃, 25℃, 35℃, and 45℃, respectively.

[0123] Table 7 shows the critical pore size D for packed adsorption when the partial pressure of benzene is 30 mbar, calculated according to equation (6). C The corresponding values ​​between the adsorption temperature T and the adsorption temperature T.

[0124] T(℃) P(mbar) <![CDATA[P0]]> k value <![CDATA[D C (nm)]]> 5 30 49.58 0.250 9.3 15 30 79.03 0.146 6.2 25 30 127.61 0.087 4.4 35 30 198.63 0.053 3.4 45 30 299.2 0.034 2.8

[0125] Where P0 is the saturated vapor pressure of benzene at the corresponding temperature (unit: mbar). Analysis of the pore size distribution of a series of MCM-41 model adsorbents with concentrated pore sizes and the static adsorption isotherms for benzene revealed that within a certain temperature range, as the adsorption temperature decreases, VOCs can form a packed adsorption in larger pores, promoting an increase in adsorption capacity. This trend also exists in the adsorption of other VOCs, such as benzene. To verify the practicality of the adsorbent selection method of this invention, a fixed-bed adsorption device coupled with gas chromatography was used to test the dynamic adsorption results of the adsorbent material for VOCs at multiple adsorption temperatures.

[0126] To verify the above pattern, MCM-4.5 material was selected, and a dynamic breakthrough experiment was conducted under the condition of benzene-containing waste gas with a partial pressure of 30 mbar. The dynamic breakthrough curve of MCM-4.5 material was obtained, as shown below. Figure 16 As shown in Table 8, the breakthrough adsorption capacity and saturation adsorption capacity of dynamic adsorption were calculated according to formula (3). Figure 17 and Figure 18 As shown, the total pore volume of the MCM-4.5 material is 0.802 cm³. 3 / g, Dynamic saturated adsorption capacity and dynamic breakthrough adsorption capacity of MCM-4.5 for benzene-containing waste gas with a partial pressure of 30mbar at multiple adsorption temperatures.

[0127] Table 8. Dynamic saturated adsorption capacity and dynamic breakthrough adsorption capacity of MCM-4.5 adsorbent material for benzene-containing waste gas at a partial pressure of 30 mbar at multiple adsorption temperatures.

[0128]

[0129] Based on the above, this embodiment verifies the generalizability of the proposed adsorbent selection method by using different types of VOCs. Through static adsorption isotherms of various model adsorbents under different temperature conditions, a ternary matching equation is constructed between VOCs partial pressure, adsorbent pore size, and adsorption temperature. Based on this equation, the critical pore size D for high pore volume utilization in packed adsorption at adsorption temperature T and partial pressure P can be obtained. C This further reveals that the equation also applies to dynamic adsorption processes, proving that this selection method can be widely applied to the screening of adsorbents for different types of VOCs. This allows for the targeting of VOC emissions at specific concentrations, based on the critical pore size D of packed adsorption at different temperatures. C The ability to promote the formation of high-pore-volume-utilization packed adsorption in larger pore sizes by lowering the adsorption temperature provides a reference for the formation of high-pore-volume-utilization packed adsorption, and ultimately establishes a general selection framework applicable to a variety of VOCs.

[0130] Example 4

[0131] This embodiment further verifies the influence of the adsorbent selected under this selection method on the desorption process. Based on Example 3, MCM-4.0 material was selected, and a dynamic breakthrough experiment was conducted under the condition of benzene-containing waste gas flow with a partial pressure of 30 mbar. The dynamic breakthrough curve of MCM-4.0 was obtained, as shown below. Figure 19 As shown in Table 9, the breakthrough adsorption capacity and saturation adsorption capacity of dynamic adsorption were calculated respectively, and the results are shown in Table 9 to verify the optimization effect of the selection method on desorption performance. Furthermore, the critical pore size D required to form a packed adsorption system for organic waste gas with a benzene partial pressure of 30 mbar was calculated. C A comparison of its pore size and position with that of the adsorbent material MCM-4.0, such as... Figure 20 As shown, it is clear whether the material meets the selection criteria under rated operating conditions.

[0132] Table 9. Dynamic saturated adsorption capacity and dynamic breakthrough adsorption capacity of MCM-4.0 adsorbent material for benzene-containing waste gas at a partial pressure of 30 mbar at multiple adsorption temperatures.

[0133]

[0134] The total pore volume of the MCM-4.0 material is 0.831 cm³. 3 The dynamic saturated adsorption capacity, dynamic breakthrough adsorption capacity, and adsorption capacity per unit pore volume of MCM-4.0 for benzene-containing waste gas at a partial pressure of 30 mbar at multiple adsorption temperatures are shown in Table 9. Figure 21As shown, for organic waste gas with a benzene partial pressure of 30 mbar, the calculated upper limit of the suitable pore size of the adsorption material decreases from 9.3 nm to 2.8 nm as the adsorption temperature increases from 5℃ to 45℃. MCM-4.0 material with a pore size distribution of 3.5-4.5 nm meets the requirements at 5℃ and 15℃, achieving filled adsorption with a high adsorption capacity per unit pore volume. At 25℃, most pores can still be filled, and the dynamic saturated adsorption capacity remains high, but the breakthrough adsorption capacity decreases by 33%. At 35℃ and 45℃, due to the pore size exceeding the limit, mainly covered adsorption occurs, and the adsorption capacity decreases significantly.

[0135] In this embodiment, the MCM-4.0 material underwent five adsorption tests at 5°C, demonstrating excellent cycling performance. Figure 22 As shown in (a) and (b), desorption was performed at 30℃, 40℃, 50℃, 60℃, and 70℃, respectively. The complete desorption times were found to be 30 min, 23 min, 23 min, 18 min, and 18 min, respectively. Compared to traditional microporous activated carbon materials, which typically require desorption temperatures above 100℃, the desorption temperature is significantly lower. Using the adsorption process guided by this selection method, for the MCM-4.0 material, high pore volume utilization rate of packed adsorption can be achieved at 5℃. Within the temperature range of 35℃ (desorption temperature 40℃), efficient desorption of VOCs and regeneration of the adsorbent can be achieved in only 23 minutes, demonstrating that the adsorbent selected by this method can reduce desorption energy consumption while ensuring high adsorption capacity.

[0136] Therefore, the adsorbent selection method of the present invention can calculate the critical pore size of packed adsorption based on the partial pressure (i.e., concentration) of VOCs and the adsorption temperature, thereby determining a suitable pore size range for the adsorbent. Based on this, the adsorption force of the adsorbent on VOCs will be in a suitable state, i.e., due to the pore size matching critical size D. C The adsorption forces are sufficient to form a packed adsorption system with high pore volume utilization, and there is no significant excess adsorption force. By controlling the temperature of the adsorbent bed, the formation and destruction of a packed adsorption system with high pore volume utilization can be achieved within a narrow temperature range. The adsorbent selected using this method can improve pore volume utilization while reducing the difficulty of desorption.

[0137] Example 5

[0138] Through Examples 1-4, a method for selecting adsorbents suitable for high concentrations of VOCs at different temperatures was established by constructing a ternary matching equation. In this example, the established adsorbent selection method was applied to the adsorption of acetone. Static adsorption isotherms of acetone using MCM-3.0, MCM-4.0, and MCM-4.5 at 5℃, 15℃, 25℃, 35℃, and 45℃ were obtained, as shown below. Figure 23As shown. Using the method of Example 1, the critical pore size (D) of acetone for packed adsorption was obtained by static adsorption isotherms. C ) and pressure (P) C The linear relationship between acetone adsorbents and the ternary matching relationship between critical pore size, partial pressure, and temperature is established. This relationship is the main calculation basis for the selection of acetone adsorbents, such as equation (7) and Figure 24 As shown.

[0139] D C =(0.093×exp(-T / 16.8)+0.005)×P C +1.7; (7)

[0140] Based on this, such as Figure 25 As shown, the critical pore sizes of acetone-filled adsorption at 100 mbar at 15℃, 25℃, 35℃ and 45℃, calculated according to equation (7), are 6.0 nm, 4.3 nm, 3.4 nm and 2.8 nm, respectively.

[0141] Using the method of Example 2, the dynamic adsorption performance of MCM-4.0 material for acetone with a partial pressure of 100 mbar at 15℃, 25℃, 35℃, and 45℃ was tested. Figure 25 As shown in Table 10, the dynamic breakthrough adsorption capacity and dynamic saturation adsorption capacity calculated using formula (3) are used to verify the applicability of the selection method to acetone adsorption.

[0142] Table 10. Dynamic saturation and dynamic breakthrough adsorption capacities of MCM-4.0 adsorbent for acetone at 100 mbar

[0143]

[0144]

[0145] Based on the above, it can be found that for organic waste gas with an acetone partial pressure of 100 mbar, as the adsorption temperature increases from 15℃ to 45℃, the upper limit of the calculated suitable pore size of the adsorption material decreases from 6.0 nm to 2.8 nm. The MCM-4.0 material with a pore size distribution of 3.5-4.5 nm meets the requirements at 15℃ and 25℃ (at 25℃, the difference between breakthrough and saturation adsorption is large due to the concentration gradient in the bed). At 35℃ and 45℃, due to the pore size exceeding the limit, the adsorption is mainly by covering, and the adsorption capacity is low. This verifies the rationality of the selection method and its indicative role in high-temperature operating conditions.

[0146] In addition, there is a similar pore size matching relationship between Example 5 and Examples 1-4, which proves that the developed adsorbent selection method determines the critical pore size under the corresponding adsorption conditions by adjusting the adsorption temperature. This method can be extended to the selection of adsorbents for different types of VOCs and has high application potential.

[0147] Therefore, by adopting the above-mentioned method and application for selecting high-concentration VOCs adsorbents at different temperatures, and by constructing a ternary matching equation of VOCs partial pressure, temperature and critical pore size, the precise selection of high-concentration VOCs adsorbents at different temperatures can be achieved. This can improve pore volume utilization and adsorption capacity while reducing desorption energy consumption and VOCs pyrolysis risk, providing a theoretical basis for adsorbent selection and technology optimization.

[0148] This document uses specific examples 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. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for selecting high-concentration VOCs adsorbents at different temperatures, characterized in that, Includes the following steps: S1. Select two or more porous materials with concentrated pore size distribution as model adsorption materials and test their pore structure parameters. S2. Test the static adsorption isotherms of the model adsorbent material for VOCs at different temperatures, determine the critical pressure corresponding to the packed adsorption, and establish the linear relationship equation between the critical pore size and the critical pressure through linear fitting: D C <k×P C +D0; In the formula, D C Critical pressure P C The critical pore size at which packed adsorption can occur, P C For an aperture size of D C The critical pressure required for packed adsorption to occur is given by k, where k is the slope of the linear relationship between the critical pore size and the critical pressure, and D0 is the critical pore size D when the pressure approaches 0 in the linear relationship. C The value; S3. Based on the aforementioned linear relationship equation, determine the variation law of critical pore size with adsorption temperature under the same partial pressure, construct the correlation equation between critical pore size and temperature and partial pressure, and form an adsorbent selection method suitable for high concentrations of VOCs at different temperatures; the correlation equation is: D C =f(T)×P C +D0; In the formula, D C P represents the critical pore size at different adsorption temperatures T under the same partial pressure, corresponding to the conditions for packed adsorption. C For an aperture size of D C The critical pressure required for packed adsorption to occur is given by k = f(T), which represents the slope of the linear relationship between the critical pore size and the critical pressure. k is a function of temperature T. S4. Test the dynamic adsorption breakthrough curve of the model adsorbent material for a certain concentration of VOCs at different temperatures, calculate the dynamic breakthrough and saturation adsorption amount, and obtain the dynamic adsorption results. S5. Based on the dynamic adsorption results and in conjunction with the above selection method, determine the appropriate pore size distribution range and selection criteria for high-concentration VOCs adsorbents at different temperatures.

2. The method for selecting high-concentration VOCs adsorbents at different temperatures according to claim 1, characterized in that, In step S1, the pore structure parameters include pore diameter distribution, pore volume, and specific surface area, which are obtained by testing using a DFT cylindrical pore calculation model.

3. The method for selecting high-concentration VOCs adsorbents at different temperatures according to claim 1, characterized in that, The model adsorbent material is one or more of ordered mesoporous carbon, ordered mesoporous silica, or molecular sieve, and the pore size is distributed in the range of micropores and small mesopores.

4. The method for selecting high-concentration VOCs adsorbents at different temperatures according to claim 1, characterized in that, In step S2, the critical pressure P C This represents the midpoint of the pressure range corresponding to the rapid increase in adsorption amount during the static adsorption isotherm.

5. The method for selecting high-concentration VOCs adsorbents at different temperatures according to claim 1, characterized in that, The VOCs are one of the following: hydrocarbons, oxygen-containing, halogen-containing, nitrogen-containing, or sulfur-containing organic compounds.

6. The method for selecting high-concentration VOCs adsorbents at different temperatures according to claim 1, characterized in that, In step S4, the dynamic breakthrough and saturation adsorption amounts are calculated using the following formula: Where Q is the dynamic breakthrough adsorption amount Q dp Or dynamic saturated adsorption capacity Q ds F is the total gas flow rate, M is the molar mass of the adsorbate, and V is the total gas flow rate. m The value is the molar volume of gas under standard conditions, taken as 22.4 L / mol, where m is the net weight of the adsorbent, c0 is the initial VOCs concentration at the inlet of the adsorbent bed, and c i t represents the VOCs concentration at the outlet of the adsorbent bed and t represents the adsorption time.

7. The method for selecting high-concentration VOCs adsorbents at different temperatures according to claim 6, characterized in that, Calculate the dynamic breakthrough adsorption capacity Q dp At that time, the outlet concentration c i =5% × c0, corresponding to the penetration time t dp The time taken for the VOCs concentration at the outlet of the adsorbent bed to reach 5% of the inlet concentration; Calculate the dynamic saturated adsorption capacity Q ds At that time, the outlet concentration c i =c0, corresponding to the saturation time t ds This is the time required for the adsorbent bed outlet concentration to be the same as the inlet concentration.

8. The application of the method for selecting high-concentration VOCs adsorbents at different temperatures according to any one of claims 1 to 7 in the selection of VOCs adsorbents, characterized in that, It is suitable for high-concentration VOCs waste gas treatment scenarios in the chemical, pharmaceutical, and petrochemical industries.

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