Industrial organic waste gas adsorbent type selection method capable of crossing adsorption temperatures and application of industrial organic waste gas adsorbent type selection method

Abstract

The invention provides a cross-adsorption-temperature industrial organic waste gas adsorbent type selection method and application, two or more model adsorption materials with concentrated pore size distribution are used, and filling type adsorption with high pore volume utilization rate can be formed in pores with a specific size or below due to adsorption of volatile organic compounds (VOCs) on a porous material; and a matching relation equation between the filling type adsorption critical aperture and the adsorption partial pressure and a rule of changing along with the adsorption temperature are explored. According to the method, the partial pressure is normalized relative to the saturated vapor pressure at the respective adsorption temperature, and the parameter saturated vapor pressure related to the adsorption temperature is introduced into an equation as a variable, so that an equation of critical pore diameters suitable for adsorption of VOCs at different temperatures and concentrations is established; and a cross-adsorption-temperature industrial organic waste gas adsorbent type selection method is formed. The method provided by the invention can provide a quantitative reference basis for development of VOCs efficient adsorption materials and technologies suitable for different adsorption temperatures.

Description

Technical Field

[0001] The present invention belongs to the technical field of waste gas treatment, and in particular relates to a method for selecting an adsorbent for industrial organic waste gas across adsorption temperatures and its application. Background Art

[0002] The adsorption technology for treating VOCs has been widely applied. However, due to numerous influencing factors in the VOCs adsorption process, there is still a lack of quantitative reference bases such as suitable pore sizes at different temperatures for the selection of adsorption materials in the current VOCs adsorption field, making it difficult to meet and support the requirements of the current refined, resource-based, and in-depth treatment of VOCs control. This has become the key limiting the development and application of VOCs adsorption recovery technology.

[0003] Based on the correlation between the VOCs adsorption isotherm and the pore size, the critical pore size of the pore channels where packed adsorption occurs and its variation trend with pressure and adsorption temperature are obtained. It is very likely to obtain the pore size range suitable for the adsorption of VOCs with different concentrations. This suitable pore size range will be able to provide a reference basis for the selection of adsorbents suitable for organic waste gas with different adsorption temperatures and concentrations. In existing research, the invention patents with patent numbers 202410699302.6 and 202310610575.4, as well as the journal article (J. Am. Chem. Soc. 2024, 146, 49, 33434 - 33442), provide a method for selecting an adsorbent suitable for VOCs, which can obtain the pore size range suitable for the adsorption of VOCs with different concentrations and provide reference bases such as suitable pore sizes for the selection and design of adsorbents. However, the equations obtained in the above patents and journal articles can only be used for the calculation of the critical pore size at a specific adsorption temperature and cannot be used for other adsorption temperatures. When the adsorption temperature changes, it is necessary to re-derive the critical pore size calculation equation at the corresponding adsorption temperature, which to a certain extent limits the convenience and popularization of the adsorbent selection method.

[0004] Both the adsorption temperature and the VOCs concentration are key factors affecting the adsorption process. Research shows that reducing the adsorption temperature can promote the occurrence of packed adsorption with high pore volume utilization in larger-sized pores. Based on this, the regulation of the adsorption temperature is very likely to become an important means for the future optimization of adsorption technology. Therefore, the selection basis for VOCs at a certain specific temperature cannot fully reflect the adsorption performance of the adsorbent at different adsorption temperatures. If the adsorption amounts of VOCs of the adsorbent at multiple temperatures are tested according to a specific temperature gradient within a relatively wide temperature range, it will lead to heavy workloads and is not conducive to the popularization and application of the technology.

[0005] At present, there is no calculation method for the critical pore diameter of packed adsorption that can be generalized to different temperatures and concentrations, which to a certain extent restricts the development of adsorption materials dedicated to the adsorption of specific VOCs and the optimization of adsorption technologies. At present, there is still a lack of an adsorbent selection method that can use the same equation to calculate the critical pore diameter of packed adsorption at different adsorption temperatures. Summary of the Invention

[0006] The purpose of the present invention is to provide an adsorbent selection method and application for industrial organic waste gas across adsorption temperatures. By introducing core parameters related to adsorption temperature (such as saturated vapor pressure) as variables into the critical pore diameter calculation model of packed adsorption with high pore volume utilization rate, an adsorbent selection method for industrial organic waste gas across adsorption temperatures is formed, providing a quantifiable reference basis such as pore size range for the selection of VOC adsorbents applicable to different adsorption temperatures and concentrations.

[0007] To achieve the above object, the present invention provides an adsorbent selection method for industrial organic waste gas across adsorption temperatures, including the following steps:

[0008] (1) Provide two or more porous materials with concentrated pore size distributions as model adsorption materials, test the pore structure parameters, and test the static adsorption isotherms of the adsorption materials for specific VOCs at multiple adsorption temperatures;

[0009] (2) By dividing each pressure point on the static adsorption isotherm by the saturated vapor pressure P0 at the corresponding temperature, obtain the static adsorption isotherm after partial pressure normalization, and determine the middle point P at the corresponding rapidly rising stage when packed adsorption occurs. C The corresponding normalized critical relative pressure P C / P0 value;

[0010] (3) Through linear fitting of the critical relative pressures P C / P0 at different temperatures in the same pore size, obtain the linear relationship equation between the critical relative pressure P C / P0 and the adsorption temperature T at a specific pore size:

[0011] P C / P0 = k × T + d (1);

[0012] Among them, T is the adsorption temperature, k is the slope of the linear relationship between the relative pressure and the adsorption temperature, and d is the value of P C / P0 when the relative pressure approaches 0 in the linear relationship;

[0013] (4) Based on equation (1), calculate the critical relative pressures P CSolve the linear relationship equation between / P0 and the adsorption temperature T to obtain the coefficients k and d of the equation in the pores of the corresponding size;

[0014] (5) For multiple pore diameters, the critical relative pressure P C / P0 and the k and d of the linear relationship equation between the adsorption temperature T are linearly fitted with respect to their respective critical pore diameters D C to obtain the linear relationship equation of the packed adsorption critical relative pressure P C / P0 varying with the adsorption temperature T and the critical pore diameter D C :

[0015] P C / P0 = (k1 × D C + k0) × T + (d1 × D C + d0) (2);

[0016] In the formula, k1 and k0 are the slope and intercept in the functional relationship k = f(D C ) = k1 × D C + k0 respectively, and d1 and d0 are the slope and intercept in the functional relationship d = g(D C ) = d1 × D C + d0 respectively;

[0017] (6) Use equation (2) to judge the appropriate pore size range of the VOCs adsorbent under different adsorption temperatures and VOCs concentrations, providing a reference basis for the selection of the model adsorption material;

[0018] (7) Verify the selection of the model adsorption material using formula (2).

[0019] Preferably, the number of the adsorption materials with a concentrated pore size distribution ≥ 2.

[0020] Preferably, the step (1) further includes:

[0021] Obtain the pore structure parameters of the adsorption material through the test of a commercial specific surface area and pore structure analyzer and the calculation model of DFT cylindrical pores. The pore structure parameters include pore size distribution and total pore volume V t .

[0022] Preferably, the adsorption material is one or more of activated carbon, porous silica, and molecular sieve.

[0023] Preferably, the VOCs is one of hydrocarbon organic compounds, oxygen-containing organic compounds, halogen-containing organic compounds, nitrogen-containing organic compounds, and sulfur-containing organic compounds.

[0024] Preferably, in the step (1), the number of multiple adsorption temperatures ≥ 2.

[0025] Preferably, the formula (2) is used to verify the selection of the model adsorption material, and the specific process is as follows:

[0026] First, test the dynamic adsorption breakthrough curve of the model adsorption material for VOCs with a specific concentration at different adsorption temperatures. According to the breakthrough time and saturation time of the dynamic adsorption breakthrough curve, combined with the flow rate of the waste gas, the concentration of VOCs, and the dosage of the adsorbent, calculate the dynamic breakthrough adsorption amount and dynamic saturation adsorption amount of VOCs at a specific concentration.

[0027] Then, according to the appropriate pore size range of the VOCs adsorbent at different temperatures obtained from Equation (2), combined with the pore size distribution of the adsorption material, calculate the pore volume utilization rate to verify the accuracy of the obtained basis for adsorbent selection.

[0028] The application of the method for selecting an adsorbent for industrial organic waste gas across adsorption temperatures in the treatment, recovery, and development of special adsorption materials for VOCs.

[0029] The technical effects of a method for selecting an adsorbent for industrial organic waste gas across adsorption temperatures are as follows:

[0030] Based on the fact that the adsorption of VOCs on porous materials forms a filling adsorption in pores smaller than a specific size, and filling adsorption is a high-pore-volume-utilization adsorption method, explore the influence law of adsorption temperature on the critical pore diameter. Using the method of controlling variables, use two or more porous materials with a concentrated pore size distribution as model adsorption materials to explore the matching relationship equation between the critical pore diameter of filling adsorption and the adsorption partial pressure, and its variation law with the adsorption temperature.

[0031] In the present invention, by normalizing the partial pressure with respect to the saturated vapor pressure at their respective adsorption temperatures and introducing parameters related to the adsorption temperature (such as saturated vapor pressure) as variables into the equation, an equation for the critical pore diameter applicable to the adsorption of VOCs at different temperatures and concentrations is established, forming a method for selecting an adsorbent for industrial organic waste gas across adsorption temperatures, providing a quantifiable reference basis such as the pore size range for the selection of adsorbents for VOCs adsorption at different adsorption temperatures and concentrations, as Figure 1 shown. The method of the present invention can provide a reference basis for the development of high-efficiency adsorption materials and technologies for VOCs at different temperatures. Description of the Drawings

[0032] Figure 1 Schematic diagram providing a quantifiable reference basis such as the pore size range for the selection of adsorbents for VOCs adsorption at different adsorption temperatures and concentrations;

[0033] Figure 2 Pore size distribution diagram of the model adsorption material;

[0034] Figure 3 The static adsorption isotherm of benzene by the model adsorption material at multiple adsorption temperatures; Figure 3 (a) The static adsorption isotherm of benzene by the adsorption material MCM-41-3.0 at multiple adsorption temperatures; Figure 3 (b) The static adsorption isotherm of benzene by MCM-41-4.0 at multiple adsorption temperatures; Figure 3 (c) The static adsorption isotherm of benzene by MCM-41-4.5 at multiple adsorption temperatures;

[0035] Figure 4 The normalized static adsorption isotherm of benzene obtained relative to the saturated vapor pressure at each temperature; Figure 4 (a) The normalized static adsorption isotherm of benzene by the adsorption material MCM-41-3.0 obtained relative to the saturated vapor pressure at each temperature; Figure 4 (b) The normalized static adsorption isotherm of benzene by MCM-41-4.0 obtained relative to the saturated vapor pressure at each temperature; Figure 4 (c) The normalized static adsorption isotherm of benzene by MCM-41-4.5 obtained relative to the saturated vapor pressure at each temperature;

[0036] Figure 5 The linear relationship equation between the critical relative pressure (P C / P0) of the filling adsorption of benzene in pores of different sizes (3.0, 4.0, 4.5 nm) and the adsorption temperature (T);

[0037] Figure 6 The linear relationship equation of the coefficients k and d in Equation (1) varying with the critical pore diameter D during the adsorption process of benzene at different temperatures; C ;

[0038] Figure 7 The pore size distribution of MCM-41-4.5 and the corresponding critical pore diameters capable of filling adsorption for benzene-containing waste gas with a partial pressure of 30 mbar at adsorption temperatures (5, 15, 25, 35, 45 °C);

[0039] Figure 8 The dynamic adsorption breakthrough curves of MCM-41-4.5 material for benzene-containing waste gas with a partial pressure of 30 mbar at multiple temperatures;

[0040] Figure 9 The pore volume utilization rate of MCM-41-4.5 with a pore size mainly distributed between 4.0 - 6.0 nm for the adsorption of benzene-containing waste gas with a partial pressure of 30 mbar under different adsorption conditions;

[0041] Figure 10Pore size distribution of the adsorbent MCM-41-4.0, and the critical pore sizes corresponding to the packed adsorption of benzene-containing waste gas at a partial pressure of 30 mbar at adsorption temperatures (5, 15, 25, 35, 45 °C);

[0042] Figure 11 Dynamic adsorption breakthrough curves of MCM-41-4.0 material for benzene at 30 mbar at multiple temperatures;

[0043] Figure 12 Pore volume utilization rates of MCM-41-4.0 with pore sizes mainly distributed between 3.0 - 5.0 nm for benzene-containing waste gas at a partial pressure of 30 mbar at different adsorption temperatures;

[0044] Figure 13 Static adsorption isotherms of the model adsorbent for acetone at 5 °C, 15 °C, 25 °C, 35 °C, 45 °C; Figure 13 (a) Static adsorption isotherms of the adsorbent MCM-41-3.0 for acetone at 5 °C, 15 °C, 25 °C, 35 °C, 45 °C; Figure 13 (b) Static adsorption isotherms of the adsorbent MCM-41-4.0 for acetone at 5 °C, 15 °C, 25 °C, 35 °C, 45 °C; Figure 13 (c) Static adsorption isotherms of the adsorbent MCM-41-4.5 for acetone at 5 °C, 15 °C, 25 °C, 35 °C, 45 °C;

[0045] Figure 14 Normalized static adsorption isotherms of acetone obtained with respect to the saturated vapor pressure at each temperature; Figure 14 (a) Normalized static adsorption isotherms of acetone for MCM-41-3.0 obtained with respect to the saturated vapor pressure at each temperature; Figure 14 (b) Normalized static adsorption isotherms of acetone for MCM-41-4.0 obtained with respect to the saturated vapor pressure at each temperature; Figure 14 (c) Normalized static adsorption isotherms of acetone for MCM-41-4.5 obtained with respect to the saturated vapor pressure at each temperature;

[0046] Figure 15 Linear relationship equations between the critical relative pressure (P C / P0) and the adsorption temperature (T) in pores of different sizes (3.0, 4.0, 4.5 nm);

[0047] Figure 16 Linear relationship equations for the coefficients k and d in Equation (1) varying with the critical pore size D C during the adsorption process of acetone at different adsorption temperatures;

[0048] Figure 17 The pore size distribution of the adsorbent material MCM-41-4.5, and the critical pore sizes corresponding to the acetone-containing waste gas with a partial pressure of 100 mbar at adsorption temperatures (5, 15, 25, 35, 45 °C) where filling adsorption can occur;

[0049] Figure 18 The dynamic adsorption breakthrough curves of the MCM-41-4.5 material for acetone with a partial pressure of 100 mbar at multiple temperatures;

[0050] Figure 19 The pore volume utilization rate of MCM-41-4.5 with pore sizes mainly distributed between 4.0 - 6.0 nm for the adsorption of acetone-containing waste gas with a partial pressure of 100 mbar at different adsorption temperatures;

[0051] Figure 20 The pore size distribution of the adsorbent material MCM-41-4.0, and the critical pore sizes corresponding to the acetone-containing waste gas with a partial pressure of 100 mbar at adsorption temperatures (5, 15, 25, 35, 45 °C) where filling adsorption can occur;

[0052] Figure 21 The dynamic adsorption breakthrough curves of the MCM-41-4.0 material for 100 mbar acetone at multiple temperatures;

[0053] Figure 22 The pore volume utilization rate of MCM-41-4.0 with pore sizes mainly distributed between 3.0 - 5.0 nm for the adsorption of acetone-containing waste gas with a partial pressure of 100 mbar at different adsorption temperatures. Detailed implementation mode

[0054] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0055] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those of ordinary skill in the field to which the present invention belongs.

[0056] Example 1

[0057] A method for selecting an adsorbent for industrial organic waste gas across adsorption temperatures, comprising the following steps:

[0058] Using a series of ordered mesoporous silica MCM-41 materials with concentrated pore size distributions as model adsorbent materials, namely MCM-41-3.0, MCM-41-4.0, and MCM-41-4.5. Using a commercial pore structure and specific surface area tester, the pore size distributions of the materials are obtained through the DFT cylindrical pore calculation model. It can be seen that the series of adsorbent materials have concentrated pore size distributions, and the most probable pore sizes are 3.0 nm, 4.0 nm, and 4.5 nm, respectively, asFigure 2 as shown

[0059] The static adsorption amounts of benzene of three model adsorbents with the most probable pore diameters of 3.0, 4.0, and 4.5 nm were tested using an intelligent gravimetric analyzer (IGA) at 5 °C, 15 °C, 25 °C, 35 °C, and 45 °C, and the static adsorption isotherms were obtained, as Figure 3 shown

[0060] According to the Kelvin equation, the adsorption of gas molecules on porous materials will form a filling adsorption in pores smaller than a specific size. The static adsorption of benzene on a series of model adsorbents dominated by mesopores is a typical type-IV adsorption isotherm, which can be roughly divided into three stages: in the initial stage of adsorption, as the pressure increases, the adsorption capacity rapidly reaches a plateau and then increases slowly, which is attributed to the process of benzene molecules gradually forming a monolayer or multilayer adsorption on the mesopore surface; in the middle stage of adsorption, the adsorption amount of benzene rises rapidly on the isotherm, which is caused by capillary condensation occurring in the concentrated mesopores; in the third stage of adsorption, the isotherm reaches a second plateau and the adsorption amount increases slowly, which is mainly due to the rearrangement of benzene molecules adsorbed in the pores in a volume filling manner, resulting in a slight increase in the adsorption amount. Among them, the filling adsorption caused by capillary condensation occurring in the middle stage of the type-IV adsorption isotherm is an adsorption method with a high pore volume utilization rate and makes a large contribution to the adsorption amount.

[0061] By dividing each pressure point on the adsorption isotherm by the saturated vapor pressure at the corresponding temperature, the static adsorption isotherm after partial pressure normalization was obtained, as Figure 4 shown. According to the adsorption isotherms after normalization of 3 model adsorbents (pore diameters of 3.0, 4.0, and 4.5 nm) at multiple temperatures (5, 15, 25, 35, 45 °C), the midpoint (critical relative pressure P C / P0) of the rapid rise stage corresponding to the occurrence of filling adsorption was determined, as shown in Table 1.

[0062] Table 1 Critical relative pressure (P C / P0) at the midpoint of the rapid rise stage corresponding to the occurrence of filling adsorption on the normalized adsorption isotherm

[0063]

[0064] By matching the critical relative pressures at different temperatures in the same pore diameter with the adsorption temperature, a linear relationship equation between the critical relative pressure (P C / P0) and the adsorption temperature (T) at a specific pore diameter can be obtained by linear fitting:

[0065] P C / P0 = k × T + d (1);

[0066] wherein, P C / P0 is the critical relative pressure, i.e., the critical relative pressure with respect to the saturated vapor pressure at their respective adsorption temperatures; T is the adsorption temperature, °C; k is the slope of the linear relationship between the relative pressure and the adsorption temperature; d is the value of P C / P0 when the relative pressure approaches 0 in the linear relationship, i.e., the intercept;

[0067] Based on the adsorption isotherms at different adsorption temperatures in pores of the same aperture, by corresponding the midpoints (critical relative pressure P C / P0) corresponding to the rapid rise stage during filling adsorption at different adsorption temperatures with the temperature T and performing linear fitting, it is found that there is a good linear relationship between the critical relative pressure of the adsorption isotherms in pores of the same size at different temperatures and the adsorption temperature. The linear relationship equations between the critical relative pressure (P C / P0) and the adsorption temperature (T) in pores of different sizes are obtained, and the linear fitting results are as Figure 5 shown. The linear relationship equations are respectively:

[0068] At 3.0 nm, P C / P0 = 0.00116×T + 0.072;

[0069] At 4.0 nm, P C / P0 = 0.00152×T + 0.163;

[0070] At 4.5 nm, P C / P0 = 0.00158×T + 0.213;

[0071] By comparing the linear relationship equations between the critical relative pressure (P C / P0) and the adsorption temperature (T) at three pore diameters, it can be found that the coefficients k and d of the linear relationship equation of Equation (1) show certain differences in different pore diameters, as shown in Table 2.

[0072] Table 2 Coefficients k and d of the linear relationship equation between the critical relative pressure (P C / P0) of benzene during filling adsorption and the adsorption temperature (T) in pores of different sizes

[0073] Aperture Coefficient k Coefficient d 3.0 nm 0.00116 0.072 4.0 nm 0.00152 0.163 4.5 nm 0.00158 0.213

[0074] According to the coefficients k and d of the linear relationship equation between the critical relative pressure (P C / P0) and the adsorption temperature (T) varying with the critical pore diameter D C of the material in multiple pores of different sizes, the critical pore diameter D C for the critical relative pressure (PC The influence law of ( / P0); through linear fitting, the critical relative pressure (P C / P0) with respect to the adsorption temperature T and the critical pore diameter D C The linear relationship equation of the change is as follows:

[0075] P C / P0 = k×T + d = f(D C )×T + g(D C ) = (k1×D C + k0)×T + (d1×D C + d0) (2);

[0076] Among them, D C is the critical pore diameter at which filling adsorption can occur when the critical relative pressure is P C / P0, in nm; k = f(D C ) = k1×D C + k0 indicates that the slope k in equation (1) is a function of the critical pore diameter D C , where k1 and k0 are the slope and intercept in the functional relationship respectively; d = g(D C ) = d1×D C + d0 indicates that the intercept d in equation (1) is a function of the critical pore diameter D C , where d1 and d0 are the slope and intercept in the functional relationship respectively.

[0077] Using equation (2), the corresponding values of the critical relative pressure P C / P0 and the critical pore diameter D C at different adsorption temperatures T can be solved.

[0078] By linearly fitting the coefficients k and d in the linear relationship equation between the critical relative pressure (P C / P0) and the adsorption temperature (T) for the three different pore diameters with respect to their respective pore diameters (3.0, 4.0, 4.5 nm), the linear relationship equations of the coefficients k and d with respect to the change of the critical pore diameter D C are obtained as k = 0.00029×D C + 0.0003 and d = 0.0936×D C - 0.209, as Figure 6 shown, thus obtaining the linear relationship equation of the critical relative pressure (P C / P0) with respect to the adsorption temperature T and the critical pore diameter D C of the change:

[0079] P C / P0 = (0.00029×D C+0.0003)×T+(0.0936×D C -0.209) (3);

[0080] Using equation (3), the critical relative pressure P C / P0 for fill-type adsorption and the critical pore diameter D C at different adsorption temperatures T can be solved; and the matching relationship between the critical relative pressure P C / P0 and the adsorption temperature T at which fill-type adsorption can occur under the critical relative pressure P C / P0 can also be obtained.

[0081] Using the obtained equation (3), the linear relationship equation of the critical pore diameter D C changing with the adsorption temperature T and the critical relative pressure P C / P0 can be obtained:

[0082] D C = (P C / P0 - 0.0003×T + 0.209) / (0.00029×T + 0.0936) (4);

[0083] According to equation (4), the critical pore diameter D for benzene corresponding to different partial pressures and temperatures at which fill-type adsorption can occur can be calculated C . For example, when the partial pressure is 30 mbar, at multiple adsorption temperatures (5, 15, 25, 35, 45 °C), the corresponding critical pore diameters for fill-type adsorption are 8.55, 5.96, 4.33, 3.37, 2.77 nm respectively, as shown in Table 3. The critical pore diameters under these specific conditions can be used as the basis for adsorbent selection under the corresponding conditions. For example, for benzene-containing waste gas with a partial pressure of 30 mbar, the appropriate pore diameter at 15 °C should be less than but close to 5.96 nm.

[0084] Table 3 Corresponding values of the critical pore diameter D C for fill-type adsorption and the adsorption temperature T when the benzene partial pressure is 30 mbar

[0085] T(℃) P (mbar) <![CDATA[P0]]> <![CDATA[P C / P0]]> <![CDATA[D C > 5 30 49.58 0.605 8.55 15 30 79.03 0.380 5.96 25 30 127.61 0.235 4.33 35 30 198.63 0.151 3.37 45 30 299.20 0.100 2.77

[0086] Taking the MCM-41-4.5 material as an example, its most probable pore diameter is 4.5 nm, and its pore diameter is mainly distributed between 4.0 and 6.0 nm, as Figure 7 shown, meeting the requirement of being less than and close to the critical pore diameter of 5.96 nm calculated according to equation (4).

[0087] Test the dynamic adsorption breakthrough curves of the MCM-41-4.5 material for 30 mbar benzene at the corresponding adsorption temperatures (5, 15, 25, 35, 45 °C), asFigure 8 As shown. Test conditions: flow rate is 20 ml / min, and the dosage of adsorbent is 0.3 g. According to the time of the dynamic adsorption breakthrough curve, combined with the flow rate of the waste gas, the concentration of VOCs, and the dosage of the adsorbent, 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 equations for the dynamic breakthrough and saturation adsorption of VOCs are:

[0088]

[0089] Among them, Q is the dynamic breakthrough adsorption capacity (Q dp ) or the dynamic saturation adsorption capacity (Q ds ), g / g; F is the total gas flow rate, L / min; M is the molar mass of the adsorbate, g / mol; V m is the molar volume of the gas, V m = 22.4 L / mol; m is the net weight of the adsorbent, g; c0 is the initial VOCs concentration at the inlet of the adsorbent bed, ppm; c i is the VOCs concentration at the outlet of the adsorbent bed, ppm; t is the adsorption time, min; when calculating the dynamic breakthrough adsorption capacity (Q dp ), the outlet concentration c i = 5%×c0, and the corresponding breakthrough time (t dp ) is the time used when the VOCs concentration at the outlet of the adsorbent bed reaches 5% of the inlet concentration; when calculating the dynamic saturation adsorption capacity (Q ds ), the outlet concentration c i = c0, and the corresponding saturation time (t ds ) is the time used when the outlet concentration of the adsorbent bed is the same as the inlet concentration.

[0090] Table 4 Dynamic saturation adsorption capacity and dynamic breakthrough adsorption capacity of benzene-containing waste gas with a partial pressure of 30 mbar by the adsorption material MCM-41-4.5 at multiple adsorption temperatures

[0091]

[0092] According to the density ρ of benzene and the total pore volume V t of the adsorbent material, the theoretical total adsorption capacity Q t of the adsorbent material can be calculated.

[0093] Q t = ρ×V t (6);

[0094] In the formula, Q t is the theoretical total adsorption capacity of the adsorbent material, g / g; V t , the total pore volume of the adsorbent material, obtained from the DFT cumulative pore size distribution, cm 3 / g; ρ is the density of liquid VOCs. Since the density changes little with temperature, an average value can be taken, g / cm 3 .

[0095] The total pore volume of MCM-41-4.5 material is 0.802 cm 3 / g, and the density of benzene is about 0.877 g / cm 3 . The theoretical total adsorption capacity Q of MCM-41-4.5 material is calculated as t = ρ × V t = 0.802 cm 3 / g × 0.877 g / cm 3 = 0.703 g / g. Usually, this theoretical total adsorption capacity is relatively close to the highest point of the static adsorption isotherm.

[0096] The pore volume utilization rate η is obtained by dividing the dynamic saturation (or dynamic breakthrough) adsorption capacity by the theoretical total adsorption capacity Q t .

[0097] η = Q / Q t (7);

[0098] η is the pore volume utilization rate; Q is the dynamic saturation adsorption capacity (Q ds ) or the dynamic breakthrough adsorption capacity (Q dp ), g / g; Q t is the theoretical total adsorption capacity of the adsorbent material, g / g;

[0099] The adsorption of benzene-containing waste gas with a partial pressure of 30 mbar by MCM-41-4.5 at multiple temperatures, and its pore volume utilization rate is shown in Table 4 and Figure 9 as follows. It can be seen that the highest pore volume utilization rate at 5 °C can reach 69.0% (dynamic saturation adsorption) and 59.5% (dynamic breakthrough adsorption). It should be emphasized that although under the conditions of this adsorption pressure and temperature, a filling-type adsorption can be formed in most pores of the MCM-41-4.5 material, due to the fact that a small amount of non-VOCs (such as nitrogen) molecules will occupy a certain volume during the dynamic adsorption process, resulting in the actual adsorption capacity being lower than the theoretical total adsorption capacity Q t . As Figure 1 shown, for the dynamic adsorption process, a pore volume utilization rate of 69.0% is already close to the maximum adsorption capacity that the dynamic adsorption process can reach, and it is also close to the maximum value of the pore volume utilization rate.

[0100] According to Equation (4), for the organic waste gas with a benzene partial pressure of 30 mbar, at an adsorption temperature of 15 °C, for a suitable adsorbent material, its pore diameter should be less than and close to 5.96 nm. Through the comparison of pore volume utilization rate, it can be found that for the MCM-41-4.5 material with pore diameters mainly distributed between 4.0 - 6.0 nm, it can maintain a relatively high pore volume utilization rate of 69.6% (dynamic saturated adsorption) and 60.9% (dynamic breakthrough adsorption).

[0101] According to Equation (4), when the adsorption temperature is 45 °C, for a suitable adsorbent material, its pore diameter should be less than and close to 2.77 nm. However, the pore diameters of MCM-41-4.5 are mainly distributed between 4.0 - 6.0 nm, which cannot meet the requirement of a pore diameter less than and close to 2.77 nm. Therefore, filling adsorption with a high pore volume utilization rate cannot occur in the pores of MCM-41-4.5, and the main adsorption that occurs is covering adsorption with a low pore volume utilization rate, resulting in a relatively low pore volume utilization rate of 17.4% (dynamic saturated adsorption) and 14.3% (dynamic breakthrough adsorption).

[0102] In summary, the present invention uses two or more model adsorbent materials with a concentrated pore size distribution. According to the fact that the adsorption of VOCs on porous materials will form filling adsorption with a high pore volume utilization rate in pores below a specific size, the matching relationship equation between the critical pore diameter of filling adsorption and the adsorption partial pressure, and its variation law with the adsorption temperature are explored. By normalizing the partial pressure with respect to the saturated vapor pressure at their respective adsorption temperatures and introducing parameters related to the adsorption temperature (such as saturated vapor pressure) as variables into the equation, an equation that can solve the critical pore diameter applicable to the adsorption of VOCs at different temperatures and concentrations is obtained. Based on this equation, when the adsorption temperature T and the critical relative pressure P C / P0 are known, the corresponding critical pore diameter D at which filling adsorption with a high pore volume utilization rate can occur can be obtained C , and the adsorbent should be selected within a range less than and close to this critical pore diameter D C and have as large a pore volume as possible. The results of the dynamic adsorption test verify the effectiveness of the selection basis. An industrial organic waste gas adsorbent selection method across adsorption temperatures is formed, which can provide reference bases such as a suitable pore size range for the development of high-efficiency adsorption materials and technologies for VOCs with different concentrations at different temperatures.

[0103] Example 2

[0104] For the MCM-41-4.0 material, its most probable pore diameter is 4.0 nm, and its pore diameters are mainly distributed between 3.0 and 5.0 nm, as Figure 10 shown. The dynamic adsorption breakthrough curves of the MCM-41-4.0 material for benzene with a partial pressure of 30 mbar at the corresponding adsorption temperatures (5, 15, 25, 35, 45 °C) are tested, as Figure 11As shown. Test conditions: flow rate is 20 ml / min, adsorbent dosage is 0.3 g. According to the time of the dynamic adsorption breakthrough curve, combined with the flow rate of the waste gas, the concentration of VOCs and the adsorbent dosage, the dynamic breakthrough adsorption amount and dynamic saturation adsorption amount of VOCs at a specific concentration are calculated according to Equation (3), as shown in Table 5. Table 5 Dynamic saturation adsorption amount (Q ds ) and dynamic breakthrough adsorption amount (Q dp ) of the adsorbent material MCM-41-4.0 for benzene-containing waste gas with a partial pressure of 30 mbar

[0105]

[0106] According to Equation (6) and Equation (7), the theoretical total adsorption amount Q t and the pore volume utilization rate η of the MCM-41-4.0 material are calculated respectively. The total pore volume of the MCM-41-4.0 material is 0.831 cm 3 / g, and the density of benzene is about 0.877 g / cm 3 . The theoretical total adsorption amount

[0107] Q t = ρ×V t = 0.831 cm 3 / g×0.877 g / cm 3 = 0.729 g / g;

[0108] The pore volume utilization rates of the adsorbent material MCM-41-4.0 at multiple temperatures are shown in Table 5 and Figure 12 as shown. It can be seen that the pore volume utilization rate at 5 °C can reach up to 70.0%, which is already close to the maximum adsorption amount that can be achieved in the dynamic adsorption process and close to the maximum value of the pore volume utilization rate.

[0109] According to Equation (4), for the organic waste gas with a benzene partial pressure of 30 mbar, at an adsorption temperature of 15 °C, for a suitable adsorbent material, its pore diameter should be less than and close to 5.96 nm. Through the comparison of the pore volume utilization rates, it can be found that the MCM-41-4.0 material with pore diameters mainly distributed between 3.0 - 5.0 nm can maintain relatively high pore volume utilization rates of 64.9% (dynamic saturation adsorption) and 59.6% (dynamic breakthrough adsorption), verifying the effectiveness of the selection basis.

[0110] According to Equation (4), for the organic waste gas with a benzene partial pressure of 30 mbar, when the adsorption temperature is 45 °C, for a suitable adsorbent material, its pore diameter should be less than and close to 2.77 nm. However, the pore diameter of MCM-41-4.0 is mainly distributed between 3.0 - 5.0 nm, which cannot meet the requirement of being less than and close to 2.77 nm. Therefore, in the pores of MCM-41-4.0, filling adsorption with high pore volume utilization cannot occur, and mainly covering adsorption with low pore volume utilization occurs, resulting in relatively low pore volume utilization rates of 19.7% (dynamic saturation adsorption) and 17.3% (dynamic breakthrough adsorption).

[0111] According to Equation (4), for the organic waste gas with a benzene partial pressure of 30 mbar, when the adsorption temperature is 25 °C, the pore diameter of the adsorbent material should be less than and close to 4.33 nm. The pore diameter of MCM-41-4.0 is mainly distributed between 3.0 - 5.0 nm, and most of the pores can meet the requirement of being less than and close to 4.33 nm, while a small part of the pores is larger than 4.33 nm. Therefore, in the pores of MCM-41-4.0, filling adsorption with high pore volume utilization can occur in most pores, and covering adsorption with low pore volume utilization occurs in a part of the pores. Therefore, the pore volume utilization rate of dynamic saturation adsorption can be maintained at a relatively high level of 59.6%, but the pore volume utilization rate of dynamic breakthrough adsorption is 40.3%, and there is a large difference between the dynamic saturation adsorption capacity and the dynamic breakthrough adsorption capacity, approximately 20%.

[0112] This is mainly due to the critical pore diameter D C , which refers to that under specific adsorption conditions (temperature, partial pressure), pores with a size of the critical pore diameter D C can just undergo filling adsorption, pores with a size smaller than D C undergo filling adsorption, and pores with a size larger than D C undergo pore covering adsorption. The critical pore diameter D C is the dividing line between the two. When the benzene partial pressure is 30 mbar and the adsorption temperature is 25 °C, the critical pore diameter D C = 4.33 nm is located within the main pore diameter distribution range of 3.0 - 5.0 nm of the MCM-41-4.0 material, resulting in no surplus adsorption force for some pores near the critical pore diameter D C = 4.33 nm. A large number of pores in the adsorbent at the end of the adsorbent bed need to wait for the VOCs concentration to reach the corresponding value before they can continue to undergo filling adsorption, thus resulting in a significant decrease in the pore volume utilization rate of the dynamic breakthrough adsorption amount (40.3%) compared to the dynamic saturation adsorption amount (59.6%).

[0113] Therefore, the above dynamic adsorption test results verify the effectiveness of the selection basis. The selection of the adsorbent should be less than and close to this critical pore diameter D CWithin the range, there should be as many pores as possible, i.e., as large a pore volume as possible. It should be ensured that the pore size range contributing significantly to the pore volume is distributed below the critical pore diameter D C so that the adsorbent material can maintain a high pore volume utilization rate for both the dynamic saturation adsorption capacity and the dynamic breakthrough adsorption capacity.

[0114] Example 3

[0115] Using the ordered mesoporous silica MCM-41 materials with the series of most probable pore diameters of 3.0 nm, 4.0 nm, and 4.5 nm in Example 1 as the model adsorbent materials. Using an intelligent gravimetric analyzer (IGA), the static adsorption isotherms of the three model adsorbent materials for acetone at 5 °C, 15 °C, 25 °C, 35 °C, and 45 °C were measured, as Figure 13 shown.

[0116] By dividing each pressure point on the adsorption isotherm by the saturated vapor pressure at the corresponding temperature, the static adsorption isotherm after partial pressure normalization was obtained, as Figure 14 shown. According to the adsorption isotherms after normalization of the three model adsorbent materials (pore diameters of 3.0, 4.0, and 4.5 nm) at five temperatures (5, 15, 25, 35, 45 °C), the midpoint (critical relative pressure P C / P0) of the rapid rise stage corresponding to the occurrence of filling adsorption was determined, as shown in Table 6.

[0117] Table 6 Critical relative pressure (P C / P0) values of the midpoint of the rapid rise stage corresponding to the occurrence of filling adsorption on the adsorption isotherm after normalization

[0118]

[0119] According to the method of Example 1, by matching the critical relative pressure at different temperatures in the same pore diameter with the adsorption temperature, a linear relationship equation between the critical relative pressure (P C / P0) and the adsorption temperature (T) at a specific pore diameter can be obtained by linear fitting, i.e., Equation (1).

[0120] Based on the adsorption isotherms at different adsorption temperatures in the same pore diameter, by corresponding the midpoint (critical relative pressure P C / P0) of the rapid rise stage corresponding to the occurrence of filling adsorption at different adsorption temperatures with the adsorption temperature T and performing linear fitting, it was found that there was a good linear relationship between the critical relative pressure and the adsorption temperature of the adsorption isotherms in the same-sized pores at different temperatures. The linear relationship equations between the critical relative pressure (P C / P0) and the adsorption temperature (T) in pores of different sizes were obtained, and the linear fitting results are as Figure 15As shown, the linear relationship equations are respectively:

[0121] At 3.0 nm, P C / P0 = 0.00102×T + 0.126;

[0122] At 4.0 nm, P C / P0 = 0.00124×T + 0.247;

[0123] At 4.5 nm, P C / P0 = 0.00168×T + 0.302;

[0124] By comparing the linear relationship equations between the critical relative pressure (P C / P0) and the adsorption temperature (T) under three pore sizes (3.0, 4.0, 4.5 nm), it can be found that the coefficients k and d of the linear relationship equation P C / P0 = k×T + d show certain differences in different pore sizes, as shown in Table 7.

[0125] Table 7 Coefficients k and d of equation (1) between the critical relative pressure (P C / P0) and the adsorption temperature (T) in pores of different sizes

[0126] Aperture Coefficient k Coefficient d 3.0 nm 0.00102 0.126 4.0 nm 0.00124 0.247 4.5 nm 0.00168 0.302

[0127] According to equation (2), by linearly fitting the coefficients k and d in the linear relationship equations between the critical relative pressure (P C / P0) and the adsorption temperature (T) in three different pore sizes with respect to their respective pore sizes (3.0, 4.0, 4.5 nm), the linear relationship equations k = 0.00041×D C + 0.000253 and d = 0.118×D C - 0.227 of the coefficients k and d changing with the critical pore size D C are obtained, as Figure 16 shown, so as to obtain the linear relationship equation of the filling adsorption critical relative pressure (P C / P0) changing with the adsorption temperature T and the critical pore size D C :

[0128] P C / P0 = (0.00041×D C + 0.000253)×T + (0.118×D C - 0.227) (8);

[0129] Using this equation, the critical relative pressure P C / P0 that can undergo filling adsorption and the critical pore size D at different adsorption temperatures T can be solved.C The matching relationship therebetween; and the critical relative pressure P C / P0 at which filling adsorption can occur, and the matching relationship between the critical relative pressure P C / P0 and the adsorption temperature T.

[0130] Using the obtained equation, the critical relative pressure P C / P0 at which filling adsorption can occur, and the matching relationship between the critical pore diameter D C and the adsorption temperature T:

[0131] D C = (P C / P0 - 0.000253×T + 0.227) / (0.00041×T + 0.118) (9);

[0132] According to equation (9), when the acetone partial pressure is 100 mbar, at multiple adsorption temperatures (15, 25, 35, 45 °C), the corresponding critical pore diameters at which filling adsorption can occur are 5.91, 4.26, 3.27, 2.66 nm respectively, as shown in Table 8. The critical pore diameters under these specific conditions can be used as the basis for adsorbent selection under the corresponding conditions.

[0133] Table 8 Corresponding values of the critical pore diameter D C at which filling adsorption can occur and the adsorption temperature T when the acetone partial pressure is 100 mbar

[0134] T / ℃ P (mbar) <![CDATA[P0]]> <![CDATA[P C / P0]]> <![CDATA[D C > 15 100 195.73 0.511 5.91 25 100 306.73 0.326 4.26 35 100 464.28 0.215 3.27 45 100 681.42 0.147 2.66

[0135] For example, for the acetone-containing waste gas with a partial pressure of 100 mbar, at 15 °C, the appropriate pore diameter should be less than but close to 5.91 nm. Taking the MCM-41-4.5 material as an example, its most probable pore diameter is 4.5 nm, and its pore diameter is mainly distributed between 4.0 and 6.0 nm, as Figure 17 shown, meeting the requirement of being less than and close to the critical pore diameter of 5.91 nm calculated according to equation (9).

[0136] Test the dynamic adsorption breakthrough curves of the MCM-41-4.5 material for 100 mbar acetone at the corresponding adsorption temperatures (15, 25, 35, 45 °C), as Figure 18 shown. Test conditions: flow rate is 20 ml / min, and the adsorbent dosage is 0.3 g. According to the time of the dynamic adsorption breakthrough curve, combined with the flow rate of the waste gas, the concentration of VOCs and the adsorbent dosage, the dynamic breakthrough adsorption amount and dynamic saturated adsorption amount of VOCs at a specific concentration are calculated through equation (9), as shown in Table 9.

[0137] Table 9 Dynamic saturated adsorption capacity and dynamic breakthrough adsorption capacity of adsorbent MCM-41-4.5 for acetone with a partial pressure of 100 mbar at multiple adsorption temperatures

[0138]

[0139] Combined with the total pore volume V of the adsorbent t and the density ρ of acetone, according to equations (6) and (7) in Example 1, the theoretical total adsorption capacity Q of MCM-41-4.5 material was calculated respectively t and the pore volume utilization rate η. The total pore volume of MCM-41-4.5 material is 0.802 cm 3 / g, and the density of acetone is about 0.788 g / cm 3 . The theoretical total adsorption capacity Q of MCM-41-4.5 material was calculated t =ρ×V t =0.802 cm 3 / g×0.788 g / cm 3 =0.632 g / g. Usually, this theoretical total adsorption capacity is relatively close to the highest point of the static adsorption isotherm

[0140] The adsorption of acetone-containing waste gas with a partial pressure of 100 mbar by MCM-41-4.5 at multiple temperatures, and its pore volume utilization rate is shown in Table 9 and Figure 19 as shown. It can be seen that the highest pore volume utilization rate at 15 °C can reach 60.1% (dynamic saturation adsorption) and 54.9% (dynamic breakthrough adsorption). It should be emphasized that due to the molecular structure of acetone being slightly less regular than that of benzene, the pore volume utilization rate of acetone is lower than that of benzene. Although under the conditions of this adsorption pressure and temperature, a filling adsorption can be formed in most pores of MCM-41-4.5 material, but due to the fact that a small amount of non-VOCs (such as nitrogen) molecules will occupy a certain volume during the dynamic adsorption process, the actual adsorption capacity is lower than the theoretical total adsorption capacity Qt. For the dynamic adsorption process, a pore volume utilization rate of 60.1% is already close to the maximum adsorption capacity that the dynamic adsorption process can reach, and it is also close to the maximum value of the pore volume utilization rate

[0141] According to equation (9), for organic waste gas with an acetone partial pressure of 100 mbar, at an adsorption temperature of 15 °C, for a suitable adsorbent, its pore diameter should be less than and close to 5.91 nm. Through the comparison of pore volume utilization rates, it can be found that the MCM-41-4.5 material with pore diameters mainly distributed between 4.0 - 6.0 nm can maintain a relatively high pore volume utilization rate of 60.1% (dynamic saturation adsorption) and 54.9% (dynamic breakthrough adsorption)

[0142] According to Equation (9), when the adsorption temperature is 45 °C, for a suitable adsorbent material, its pore diameter should be less than and close to 2.66 nm. However, the pore diameter of MCM-41-4.5 is mainly distributed between 4.0 - 6.0 nm, which cannot meet the requirement of a pore diameter less than and close to 2.77 nm. Therefore, filling adsorption with high pore volume utilization cannot occur in the pores of MCM-41-4.5, and mainly covering adsorption with low pore volume utilization occurs, resulting in relatively low pore volume utilization rates of 29.5% (dynamic saturation adsorption) and 23.6% (dynamic breakthrough adsorption). It should be noted that since acetone molecules are more polar than benzene molecules, in the adsorbent material MCM-41 composed of polar SiO2, the more polar acetone molecules have stronger intermolecular forces with VOCs molecules during the formation of covering adsorption. Therefore, the adsorption capacity and pore volume utilization rate of covering adsorption are also greater. The above dynamic adsorption test results verify the effectiveness of the selection basis.

[0143] Example 4

[0144] For the MCM-41-4.0 material, its most probable pore diameter is 4.0 nm, and its pore diameter is mainly distributed between 3.0 and 5.0 nm, as Figure 20 shown. The dynamic adsorption breakthrough curves of the MCM-41-4.0 material for acetone with a partial pressure of 100 mbar were tested at the corresponding adsorption temperatures (15, 25, 35, 45 °C), as Figure 21 shown. Test conditions: flow rate is 20 ml / min, and the adsorbent dosage is 0.3 g. According to the time of the dynamic adsorption breakthrough curve, combined with the flow rate of the waste gas, the concentration of VOCs, and the adsorbent dosage, the dynamic breakthrough adsorption capacity and dynamic saturation adsorption capacity of VOCs at a specific concentration were calculated according to Equation (5), as shown in Table 10. Table 10 Dynamic saturation adsorption capacity Q of the adsorbent material MCM-41-4.0 for acetone-containing waste gas with a partial pressure of 100 mbar ds and dynamic breakthrough adsorption capacity Q dp

[0145]

[0146] Combined with the total pore volume V t of the adsorbent material and the density ρ of acetone, according to Equation (6) and Equation (7) in Example 1, the theoretical total adsorption capacity Q t of the MCM-41-4.0 material and the pore volume utilization rate η were calculated respectively. The total pore volume of the MCM-41-4.0 material is 0.831 cm 3 / g, and the density of acetone is approximately 0.788 g / cm 3 . The calculated theoretical total adsorption capacity Q t = ρ × V t = 0.831 cm 3 / g × 0.788 g / cm 3 = 0.655 g / g. The pore volume utilization rates of the adsorbent MCM-41-4.0 at multiple temperatures are shown in Table 10 and Figure 22 as follows. It can be seen that the highest pore volume utilization rate at 15 °C can reach 58.9%, which is already close to the maximum adsorption capacity that can be achieved in the dynamic adsorption process and close to the maximum value of the pore volume utilization rate.

[0147] According to Equation (9), for organic waste gas with an acetone partial pressure of 100 mbar, at an adsorption temperature of 15 °C, for a suitable adsorbent, its pore diameter should be less than and close to 5.91 nm. Through the comparison of pore volume utilization rates, it can be found that for the MCM-41-4.0 material with a pore diameter mainly distributed between 3.0 - 5.0 nm, it can maintain a relatively high pore volume utilization rate of 58.9% (dynamic saturation adsorption) and 53.5% (dynamic breakthrough adsorption).

[0148] According to Equation (9), for organic waste gas with an acetone partial pressure of 100 mbar, at an adsorption temperature of 45 °C, for a suitable adsorbent, its pore diameter should be less than and close to 2.66 nm. However, the pore diameter of MCM-41-4.0 is mainly distributed between 3.0 - 5.0 nm, which cannot meet the requirement of being less than and close to 2.66 nm. Therefore, in the pores of MCM-41-4.0, filling adsorption with a high pore volume utilization rate cannot occur, and the main adsorption that occurs is covering adsorption with a low pore volume utilization rate, resulting in a relatively low pore volume utilization rate of 29.6% (dynamic saturation adsorption) and 26.6% (dynamic breakthrough adsorption).

[0149] According to Equation (9), for organic waste gas with an acetone partial pressure of 100 mbar, at an adsorption temperature of 35 °C, the pore diameter of the adsorbent should be less than and close to 3.27 nm. The pore diameter of MCM-41-4.0 is mainly distributed between 3.0 - 5.0 nm, among which some pores can meet the requirement of being less than and close to 3.27 nm, and some pores are larger than 3.27 nm. Therefore, in the pores of MCM-41-4.0, filling adsorption with a high pore volume utilization rate can occur in some pores, and covering adsorption with a low pore volume utilization rate occurs in some other pores. Therefore, the pore volume utilization rate of dynamic saturation adsorption of 42.8% is significantly lower than that at 15 °C of 58.9%, with a difference of approximately 16.1%.

[0150] Since acetone molecules are more polar than benzene molecules, in the adsorbent MCM-41 composed of polar SiO2, for the more polar acetone molecules, during the formation of covering adsorption, there is a stronger interaction force between the material and VOCs molecules. Therefore, the adsorption capacity of covering adsorption is greater.

[0151] Therefore, the present invention adopts the above-mentioned method for selecting an adsorbent for industrial organic waste gas across adsorption temperatures and its application. By taking the adsorption temperature T and the VOCs partial pressure as variables, it is possible to obtain the critical pore diameter D corresponding to the packed adsorption with high pore volume utilization at different adsorption temperatures and VOCs concentrations using the same equation. C This critical pore diameter can be used as the basis for selecting the adsorbent. The results of the dynamic adsorption test verify the effectiveness of the selection basis. The adsorbent should be selected within a range less than and close to this critical pore diameter D C and have as many pores as possible, that is, as large a pore volume as possible. It should be ensured that the pore diameter size range that contributes more to the pore volume is distributed below the critical pore diameter D C so that the adsorbent material can maintain a high pore volume utilization rate for both the dynamic saturated adsorption capacity and the dynamic breakthrough adsorption capacity.

[0152] In summary, the present invention uses two or more model adsorbent materials with a concentrated pore size distribution. According to the fact that the adsorption of VOCs on porous materials will form a packed adsorption with high pore volume utilization in pores below a specific size, the matching relationship equation between the critical pore diameter of the packed adsorption and the adsorption partial pressure and its variation law with the adsorption temperature are explored. By normalizing the partial pressure with respect to the saturated vapor pressure at their respective adsorption temperatures and introducing parameters related to the adsorption temperature (such as the saturated vapor pressure) as variables into the equation, an equation that can solve the critical pore diameter applicable to the adsorption of VOCs at different temperatures and concentrations is obtained. Based on this equation, the adsorption temperature T and the critical relative pressure P C / P0 can be obtained, and the corresponding critical pore diameter D of the packed adsorption with high pore volume utilization can be obtained. C The adsorbent should be selected within a range less than and close to this critical pore diameter D C and have as large a pore volume as possible. A method for selecting an adsorbent for industrial organic waste gas across adsorption temperatures is formed, which can provide a reference basis such as a suitable pore diameter size range for the development of high-efficiency adsorption materials and technologies for VOCs with different concentrations at different temperatures.

[0153] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for selecting an adsorbent for industrial organic waste gas across adsorption temperatures, characterized in that, It includes the following steps: (1) Provide two or more porous materials with a concentrated pore size distribution as model adsorption materials, test the pore structure parameters, and test the static adsorption isotherms of the adsorption materials for specific VOCs at multiple adsorption temperatures; (2) By dividing each pressure point on the static adsorption isotherm by the saturated vapor pressure P0 at the corresponding temperature, a static adsorption isotherm after partial pressure normalization is obtained, and the midpoint P of the rapidly rising stage corresponding to the occurrence of filling adsorption is determined. C The corresponding normalized critical relative pressure P C / P0 value; (3) By performing a linear fit on the critical relative pressure P C / P0 at different temperatures in the same pore diameter, the linear relationship equation between the critical relative pressure P C / P0 and the adsorption temperature T at a specific pore diameter is obtained: P C / P0 = k × T + d(1); where T is the adsorption temperature, k is the slope of the linear relationship between the relative pressure and the adsorption temperature, and d is the value of P C / P0 when the relative pressure approaches 0 in the linear relationship; (4) Based on Equation (1), calculate the linear relationship equation between the critical relative pressure P C / P0 of multiple adsorption materials with concentrated apertures and the adsorption temperature T, and solve the coefficients k and d of the equation in pores of corresponding sizes; (5) By taking the k and d in the linear relationship equation between the critical relative pressure P C / P0 and the adsorption temperature T at multiple pore sizes, with respect to their respective critical pore diameters D C performing a linear fit, the linear relationship equation for the critical relative pressure P C / P0 varying with the adsorption temperature T and the critical pore diameter D C is obtained as follows: P C / P0 = (k1 × D C + k0) × T + (d1 × D C + d0) (2); where k1 and k0 are the slope and intercept in the functional relationship k = f(D C ) = k1×D C + k0, and d1 and d0 are the slope and intercept in the functional relationship d = g(D C ) = d1×D C + d0; (6) Use Equation (2) to determine the appropriate pore size range of the VOCs adsorbent under different adsorption temperatures and VOCs concentrations, providing a reference basis for the selection of model adsorption materials; (7) Verify the selection of model adsorption materials using Formula (2).

2. The method for selecting an adsorbent for industrial organic waste gas across adsorption temperatures according to claim 1, wherein The number of the adsorption materials with a concentrated pore size distribution is ≥2.

3. A method for selecting an adsorbent for industrial organic waste gas across adsorption temperatures according to claim 1, characterized in that, The step (1) further includes: Using the test of a commercial specific surface area and pore structure analyzer, the pore structure parameters of the adsorbent material are obtained through the calculation model of DFT cylindrical pores. The pore structure parameters include pore size distribution and total pore volume V t .

4. The method for selecting an adsorbent for industrial organic waste gas across adsorption temperatures according to claim 1, wherein The adsorption material is one or more of activated carbon, porous silica, and molecular sieve.

5. A method for selecting an adsorbent for industrial organic waste gas across adsorption temperatures according to claim 1, characterized in that, VOCs are one of hydrocarbon organic compounds, oxygen-containing organic compounds, halogen-containing organic compounds, nitrogen-containing organic compounds, and sulfur-containing organic compounds.

6. The method for selecting an adsorbent for industrial organic waste gas across adsorption temperatures according to claim 1, characterized in that, In the step (1), the number of multiple adsorption temperatures is ≥2.

7. A method for selecting an adsorbent for industrial organic waste gas across adsorption temperatures according to claim 1, characterized in that, Verify the selection of model adsorption materials using Formula (2), and the specific process is as follows: First, test the dynamic adsorption breakthrough curve of the model adsorption material for VOCs with a specific concentration at different adsorption temperatures. According to the breakthrough time and saturation time of the dynamic adsorption breakthrough curve, combined with the flow rate of the waste gas, the concentration of VOCs, and the dosage of the adsorbent, calculate the dynamic breakthrough adsorption amount and dynamic saturation adsorption amount of VOCs at a specific concentration; Then, based on the appropriate pore size range of the VOCs adsorbent obtained from Equation (2) at different temperatures, combined with the pore size distribution of the adsorption material, calculate the pore volume utilization rate to verify the accuracy of the obtained adsorbent selection basis.

8. Application of a method for selecting an industrial organic waste gas adsorbent applicable across adsorption temperatures according to any one of claims 1-7 in the treatment, recovery, and development of special adsorption materials for VOCs.

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