Method for selecting adsorbent for industrial organic waste gas across adsorption temperature and application thereof

Abstract

The application provides an adsorbent selection method for industrial organic waste gas across adsorption temperature and application, uses two or more model adsorbents with concentrated pore size distribution, and according to the adsorption of volatile organic compounds (VOCs) on the porous material, the filling type adsorption with high pore volume utilization rate can be formed in the pores below a certain size, the matching relationship equation between the critical pore size of the filling type adsorption and the adsorption partial pressure is explored, and the law of the equation changing with the adsorption temperature is explored. The application normalizes the partial pressure relative to the saturated vapor pressure under the respective adsorption temperature, introduces the saturated vapor pressure related to the adsorption temperature as a variable into the equation, thereby establishes the equation of the critical pore size suitable for the adsorption of VOCs with different temperatures and concentrations, and forms the adsorbent selection method for industrial organic waste gas across adsorption temperature. The method provided by the application can provide quantitative reference basis for the development of VOCs high-efficiency adsorption materials and technologies suitable for different adsorption temperatures.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of waste gas treatment, in particular to an adsorbent selection method for industrial organic waste gas across adsorption temperature and application thereof. BACKGROUND

[0002] VOCs treatment by adsorption technology has been widely applied. However, due to the numerous influencing factors of VOCs adsorption process, the selection of adsorbent materials in the current VOCs adsorption field still lacks quantitative references such as suitable pore sizes at different temperatures, making it difficult to meet the needs of fine, resourceful and deep treatment of current VOCs control, which has become a key factor limiting the development and application of VOCs adsorption recovery technology.

[0003] Based on the correlation between VOCs adsorption isotherm and pore size, the critical pore size of the pore where the filling adsorption occurs, and its variation trend with pressure and adsorption temperature are obtained. It is extremely likely to obtain a pore size range suitable for VOCs adsorption at different concentrations. This suitable pore size range will provide a reference for the selection of adsorbents suitable for organic waste gas at different adsorption temperatures and concentrations. In existing research, patent numbers 202410699302.6 and 202310610575.4, and journal article (J. Am. Chem. Soc. 2024, 146, 49, 33434-33442) provide a method for selecting VOCs adsorbents, which can obtain a pore size range suitable for VOCs adsorption at different concentrations, providing a reference for the selection and design of adsorbents. However, the equations obtained in the above patents and journal articles can only be used to calculate the critical pore size at a specific adsorption temperature, and cannot be used at other adsorption temperatures. When the adsorption temperature changes, the critical pore size calculation equation at the corresponding adsorption temperature needs to be re-derived, which to some extent limits the convenience and generalizability of the adsorbent selection method.

[0004] Both adsorption temperature and VOCs concentration are key factors affecting the adsorption process. Studies have shown that reducing the adsorption temperature can promote the occurrence of high-pore-volume filling adsorption in larger-sized pores. Based on this, the regulation of adsorption temperature is extremely likely to become an important means of future adsorption technology optimization. Therefore, the VOCs selection basis at a specific temperature cannot fully represent the adsorption performance of the adsorbent at different adsorption temperatures. If the adsorption amount of VOCs at multiple temperatures is tested according to a specific temperature gradient within a wider temperature range, it will result in heavy workload, which is not conducive to the popularization and application of the technology.

[0005] Currently, there is no calculation method of the critical pore size of packed adsorption that can be popularized to different temperatures and concentrations, which limits the development of adsorbent materials with special adsorption of specific VOCs and the optimization of adsorption technology to some extent. Currently, there is still a lack of adsorbent selection method that can calculate the critical pore size of packed adsorption at different adsorption temperatures using the same equation. SUMMARY

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

[0007] To achieve the above-mentioned purpose, the present application provides an industrial organic waste gas adsorbent selection method across adsorption temperatures, comprising the following steps:

[0008] (1) providing two or more porous materials with concentrated pore size distribution as model adsorbents, testing the pore structure parameters, and testing the static adsorption isotherm of the adsorbent on a specific VOC 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, the static adsorption isotherm after pressure normalization is obtained, and the intermediate point P of the corresponding rapid rise stage when packed adsorption occurs is determined C The normalized critical relative pressure P C / P0 value;

[0010] (3) by linear fitting the critical relative pressure P C / P0 at different temperatures for the same pore size, the linear relationship equation between the critical relative pressure P C / P0 and the adsorption temperature T at a specific pore size is obtained:

[0011] P C / P0=k×T+d(1);

[0012] wherein 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 tends to 0 in the linear relationship;

[0013] (4) based on equation (1), the critical relative pressure P Clinear relationship equation between P0 and adsorption temperature T, solve the coefficient k and d of the equation in the corresponding size of the hole;

[0014] (5) by the multiple pore size, the critical relative pressure P C linear relationship equation between P0 and adsorption temperature T, k and d, relative to the respective critical pore size D C linear fitting, get the filling type adsorption critical relative pressure P C linear relationship equation of P0 with adsorption temperature T and critical pore size D C change:

[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 of the function relationship k=f(D C )=k1×D C +k0, respectively, and d1 and d0 are the slope and intercept of the function relationship d=g(D C )=d1×D C +d0, respectively;

[0017] (6) using equation (2) to determine the suitable pore size range of VOCs adsorbent under different adsorption temperature and VOCs concentration conditions, to provide reference basis for the selection of model adsorbent;

[0018] (7) using formula (2) to verify the selection of model adsorbent.

[0019] Preferably, the number of said adsorbent with concentrated pore size distribution is ≥2.

[0020] Preferably, step (1) further comprises:

[0021] Using commercial specific surface area and pore structure analyzer test, through DFT cylindrical hole calculation model, the pore structure parameters of adsorbent are obtained, including pore size distribution, total pore volume V t .

[0022] Preferably, the adsorbent is one or more of activated carbon, porous silicon oxide and molecular sieve.

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

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

[0025] Preferably, the model adsorbent material is verified by formula (2), and the specific process is as follows:

[0026] Firstly, the dynamic adsorption breakthrough curve of the model adsorbent material at different adsorption temperatures is tested for VOCs of a specific concentration, and the dynamic breakthrough adsorption amount and the dynamic saturation adsorption amount of VOCs at a specific concentration are calculated according to the breakthrough time and the saturation time of the dynamic adsorption breakthrough curve, combined with the flow of waste gas, the concentration of VOCs and the amount of adsorbent.

[0027] Then, according to equation (2), the suitable pore size range of VOCs adsorbent at different temperatures is obtained, and the pore volume utilization rate is calculated combined with the pore size distribution of the adsorbent material, so as to verify the accuracy of the obtained adsorbent selection basis.

[0028] The adsorbent selection method suitable for industrial organic waste gas across adsorption temperature is applied to the treatment, recovery and development of special adsorbent materials of VOCs.

[0029] The technical effect of the adsorbent selection method suitable for industrial organic waste gas across adsorption temperature is as follows:

[0030] Based on the adsorption of VOCs on porous materials, the filling adsorption will be formed in the pores below a certain size, and the filling adsorption is a high pore volume utilization adsorption mode. The influence law of adsorption temperature on the critical pore size is explored. By using the method of controlling variables, two or more porous materials with concentrated pore size distribution are used as model adsorbent materials, the matching relationship equation between the critical pore size of filling adsorption and the adsorption partial pressure, and the law of change with adsorption temperature are explored.

[0031] By normalizing the partial pressure relative to the saturation vapor pressure at the respective adsorption temperature, and introducing the parameters related to the adsorption temperature (such as the saturation vapor pressure) as variables into the equation, the equation of the critical pore size suitable for VOCs adsorption at different temperatures and concentrations is established, and the adsorbent selection method suitable for industrial organic waste gas across adsorption temperature is formed, which provides quantifiable reference basis such as pore size range for the selection of VOCs adsorbent suitable for different adsorption temperatures and concentrations, as shown in the figure. Figure 1 The method of the present application can provide reference basis for the development of VOCs high-efficiency adsorbent materials and technology at different temperatures. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The figure shows the quantifiable reference basis such as pore size range for the selection of adsorbent suitable for VOCs at different adsorption temperatures and concentrations;

[0033] Figure 2 The pore size distribution graph of the model adsorbent material;

[0034] Figure 3 Static adsorption isotherms of benzene on the model adsorbents at various adsorption temperatures; Figure 3 (a) Static adsorption isotherms of benzene on the adsorbent MCM-41-3.0 at various adsorption temperatures; Figure 3 (b) Static adsorption isotherms of benzene on the adsorbent MCM-41-4.0 at various adsorption temperatures; Figure 3 (c) Static adsorption isotherms of benzene on the adsorbent MCM-41-4.5 at various adsorption temperatures;

[0035] Figure 4 Normalized static adsorption isotherms of benzene with respect to the saturated vapor pressure at various temperatures; Figure 4 (a) Normalized static adsorption isotherms of benzene with respect to the saturated vapor pressure at various temperatures for the adsorbent MCM-41-3.0; Figure 4 (b) Normalized static adsorption isotherms of benzene with respect to the saturated vapor pressure at various temperatures for the adsorbent MCM-41-4.0; Figure 4 (c) Normalized static adsorption isotherms of benzene with respect to the saturated vapor pressure at various temperatures for the adsorbent MCM-41-4.5;

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

[0037] Figure 6 Linear relationship equations for the variation of the coefficients k and d of equation (1) with the critical pore diameter D C for the adsorption of benzene at different temperatures;

[0038] Figure 7 Pore size distribution of MCM-41-4.5 and the critical pore size for the filling-type adsorption of benzene from a waste gas with a benzene partial pressure of 30 mbar at adsorption temperatures of 5, 15, 25, 35 and 45°C;

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

[0040] Figure 9 Pore volume utilization of MCM-41-4.5 with a pore size mainly distributed in the range of 4.0-6.0 nm for the adsorption of a waste gas containing benzene with a partial pressure of 30 mbar at various adsorption conditions;

[0041] Figure 10The pore size distribution of the adsorbent material MCM-41-4.0, and the critical pore size for which the filling type adsorption can occur at the adsorption temperature (5, 15, 25, 35, 45 °C) for the benzene containing waste gas with a partial pressure of 30 mbar;

[0042] Figure 11 The dynamic adsorption breakthrough curves of the MCM-41-4.0 material at various temperatures for 30 mbar benzene;

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

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

[0045] Figure 14 The normalized static adsorption isotherms of acetone relative to the saturated vapor pressure at various temperatures; Figure 14 (a) The normalized static adsorption isotherms of MCM-41-3.0 relative to the saturated vapor pressure at various temperatures; Figure 14 (b) The normalized static adsorption isotherms of MCM-41-4.0 relative to the saturated vapor pressure at various temperatures; Figure 14 (c) The normalized static adsorption isotherms of MCM-41-4.5 relative to the saturated vapor pressure at various temperatures;

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

[0047] Figure 16 The linear relationship equation of the coefficients k and d in equation (1) changing with the critical pore size D C in 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 size corresponding to the occurrence of filling-type adsorption at different adsorption temperatures (5, 15, 25, 35, 45°C) for the waste gas containing acetone with a partial pressure of 100 mbar;

[0049] Figure 18 The dynamic adsorption breakthrough curve of the MCM-41-4.5 material at different temperatures for 100 mbar of acetone;

[0050] Figure 19 The pore volume utilization of the MCM-41-4.5 material with a pore size mainly distributed between 4.0-6.0 nm for the adsorption of the waste gas containing acetone 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 size corresponding to the occurrence of filling-type adsorption at different adsorption temperatures (5, 15, 25, 35, 45°C) for the waste gas containing acetone with a partial pressure of 100 mbar;

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

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

[0054] The technical solutions of the present application are further described below through the drawings and examples.

[0055] Unless otherwise defined, the technical terms or scientific terms used in the present application shall have the usual meanings understood by a person with ordinary skills in the art to which the present application belongs.

[0056] Example 1

[0057] An industrial organic waste gas adsorbent selection method across adsorption temperatures, comprising the following steps:

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

[0059] The static adsorption capacity of three model adsorbents with most probable pore sizes of 3.0, 4.0, and 4.5 nm for benzene was measured at 5℃, 15℃, 25℃, 35℃, and 45℃ using an intelligent gravimetric analyzer (IGA). Static adsorption isotherms were obtained, such as... Figure 3 As shown.

[0060] According to the Kelvin equation, the adsorption of gas molecules on porous materials results in packed adsorption within pores of a specific size. The static adsorption of benzene on a series of predominantly mesoporous model adsorbents exhibits a typical Type IV adsorption isotherm, which can be roughly divided into three stages: In the initial stage of adsorption, the adsorption capacity rapidly reaches a plateau with increasing pressure and then increases slowly, attributed to the gradual formation of monolayers or multilayers of benzene molecules on the mesoporous surface; in the intermediate stage, the adsorption amount of benzene rises rapidly along the isotherm, caused by capillary condensation occurring in the concentrated mesopores; in the third stage, the isotherm reaches a second plateau, and the increase in adsorption amount is slow, mainly due to the rearrangement of benzene molecules adsorbed in the pores in a volume-filling manner, resulting in a slight increase in adsorption amount. Among these, the packed adsorption caused by capillary condensation in the intermediate stage of the Type IV adsorption isotherm is a high-pore-volume utilization adsorption mode that significantly contributes 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 is obtained, such as... Figure 4 As shown. Based on the normalized adsorption isotherms of three model adsorbent materials (pore sizes of 3.0, 4.0, and 4.5 nm) at multiple temperatures (5, 15, 25, 35, and 45 °C), the midpoint of the rapid rise phase (critical relative pressure P) corresponding to the occurrence of packed adsorption was determined. C / P0), as shown in Table 1.

[0062] Table 1 shows the critical relative pressure (Pc) at the midpoint of the rapid rise phase during the filling adsorption stage on the normalized adsorption isotherm. C / P0)

[0063]

[0064] By matching the critical relative pressure at different temperatures within the same pore size with the adsorption temperature, the critical relative pressure (P) at a specific pore size can be obtained through linear fitting. C The linear relationship between / P0) and adsorption temperature (T) is expressed as follows:

[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 the respective adsorption temperature; 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 intercept of the linear relationship when the relative pressure tends to 0; C / P0;

[0067] Based on the adsorption isotherms at different adsorption temperatures in the same pore size, the middle points of the corresponding rapid rising stage (critical relative pressure P C / P0) at different adsorption temperatures when filling type adsorption occurs are corresponded to the temperature T, and linear fitting is performed, and it is found that the critical relative pressure of the adsorption isotherms at different temperatures in the same size pore presents a good linear relationship with the adsorption temperature. The linear relationship equation between the critical relative pressure (P C / P0) and the adsorption temperature (T) in different size pores is obtained, and the linear fitting results are shown in Figure 5 , and the linear relationship equations are respectively:

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

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

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

[0071] Through comparison of the linear relationship equations between the critical relative pressure (P C / P0) and the adsorption temperature (T) at three pore sizes, it can be found that the coefficients k and d of the linear relationship equation (1) present certain differences in different pore sizes, 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) and the adsorption temperature (T) in different size pores of benzene filling type adsorption

[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) in a plurality of different size pores, the coefficients k and d are obtained with the change of the critical pore diameter D C of the material, and the critical pore diameter D C of the material is obtained with the change of the coefficients k and d of the linear relationship equation between the critical relative pressure (PC The influence law of / P0) can be obtained through linear fitting; the critical relative pressure (P) of the packed adsorption can be obtained. C / P0) varies with adsorption temperature T and critical pore size D C The linear relationship equation of change:

[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 For the critical relative pressure is P C At / P0, the critical pore size for packed adsorption to occur is nm; k = f(D C )=k1×D C +k0 indicates that the slope k in equation (1) is the critical aperture D. C The function, where k1 and k0 are the slope and intercept of the function, respectively; d = g(D C )=d1×D C +d0 indicates that the intercept d in equation (1) is the critical aperture D. C The function is given by d1 and d0, where d1 and d0 are the slope and intercept of the function, respectively.

[0077] Equation (2) can be used to solve for the critical relative pressure P at different adsorption temperatures T that allow for packed adsorption. C / P0 and critical aperture D C The corresponding values ​​between them.

[0078] By measuring the critical relative pressure (P) in three different orifice sizes C The coefficients k and d in the linear equation relating / P0) to adsorption temperature (T) were linearly fitted with respect to their respective pore sizes (3.0, 4.0, and 4.5 nm) to obtain the coefficients k and d as a function of the critical pore size D. C The linear relationship equation for the change is k = 0.00029 × D C +0.0003 and d = 0.0936 × D C -0.209, such as Figure 6 As shown, the critical relative pressure (P) of the packed adsorption is thus obtained. C / P0) varies with adsorption temperature T and critical pore size D C The linear relationship equation of change:

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

[0080] Equation (3) can be used to solve for the critical relative pressure P at different adsorption temperatures T that allow for packed adsorption. C / P0 and critical aperture D C The matching relationship between them; and the critical relative pressure P C The critical relative pressure P at / P0 that allows for packed adsorption C The matching relationship between / P0 and adsorption temperature T.

[0081] The critical aperture D can be obtained using the obtained equation (3). C With adsorption temperature T and critical relative pressure P C The linear relationship equation for the change of / P0:

[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 size D for benzene to undergo packed adsorption at different partial pressures and temperatures can be calculated. C For example, at a partial pressure of 30 mbar, the critical pore sizes for packed adsorption at various adsorption temperatures (5, 15, 25, 35, 45 °C) are 8.55, 5.96, 4.33, 3.37, and 2.77 nm, respectively, as shown in Table 3. These critical pore sizes under specific conditions can serve as a basis for adsorbent selection under corresponding conditions. For example, for benzene-containing waste gas with a partial pressure of 30 mbar, the suitable pore size at 15 °C should be less than but close to 5.96 nm.

[0084] Table 3 shows the critical pore size D for packed adsorption when the partial pressure of benzene is 30 mbar. C Corresponding values ​​between adsorption temperature T

[0085] T(℃) P (mbar) [P0] 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 MCM-41-4.5 material as an example, its most probable pore size is 4.5 nm, and its pore size is mainly distributed between 4.0 and 6.0 nm. Figure 7 As shown, it meets the requirement of being less than and close to the critical aperture of 5.96 nm as calculated according to equation (4).

[0087] The dynamic adsorption breakthrough curves of MCM-41-4.5 material for 30 mbar benzene were tested at the corresponding adsorption temperatures (5, 15, 25, 35, 45℃), as shown below.Figure 8 The test conditions were a flow rate of 20 ml / min and a sorbent dosage of 0.3 g. According to the time of dynamic adsorption breakthrough curve, combined with the flow rate of waste gas, the concentration of VOCs and the dosage of sorbent, the dynamic breakthrough adsorption amount and the dynamic saturation adsorption amount of VOCs at a specific concentration were calculated, as shown in Table 4. The calculation equation of the dynamic breakthrough adsorption amount and the dynamic saturation adsorption amount of VOCs is as follows:

[0088]

[0089] wherein Q is the dynamic breakthrough adsorption amount (Q dp ) or the dynamic saturation adsorption amount (Q ds ), g / g; F is the total flow rate of gas, L / min; M is the molar mass of the adsorbate, g / mol; V m is the molar volume of gas, V m = 22.4 L / mol; m is the net weight of the sorbent, g; c0is the initial VOCs concentration at the inlet of the sorbent bed, ppm; c i is the VOCs concentration at the outlet of the sorbent bed, ppm; t is the adsorption time, min; when the dynamic breakthrough adsorption amount (Q dp ) is calculated, the outlet concentration c i = 5% x c0, and the breakthrough time (t dp ) is the time used when the VOCs concentration at the outlet of the sorbent bed reaches 5% of the inlet concentration; when the dynamic saturation adsorption amount (Q ds ) is calculated, the outlet concentration c i = c0, and the saturation time (t ds ) is the time used when the outlet concentration of the sorbent bed is the same as the inlet concentration.

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

[0091]

[0092] According to the density p of benzene and the total pore volume V t of the adsorption material, the theoretical total adsorption amount Q t of the adsorption material can be calculated,

[0093] Q t = p x V t (6).

[0094] In the formula, Q t is the theoretical total adsorption amount of the adsorption material, g / g; V t is the total pore volume of the adsorption material, cm 3 / g; ρ is the density of liquid VOCs, which does not change much with temperature and can be taken as the average value, g / cm³. 3 .

[0095] The total pore volume of MCM-41-4.5 material is 0.802 cm³. 3 / g, the density of benzene is approximately 0.877g / cm³. 3 The theoretical total adsorption capacity Q of the MCM-41-4.5 material was calculated. t =ρ×V t =0.802cm 3 / g×0.877g / cm 3 =0.703 g / g. Typically, this theoretical total adsorption capacity is close to the highest point of the static adsorption isotherm.

[0096] Pore ​​volume utilization η is calculated by dividing the dynamic saturation (or dynamic breakthrough) adsorption capacity by the theoretical total adsorption capacity Q. t get,

[0097] η = Q / Q t (7);

[0098] η is the pore volume utilization rate; Q is the dynamic saturated adsorption capacity (Q0). ds ) or dynamic breakthrough adsorption capacity (Q) dp ), g / g; Q t The theoretical total adsorption capacity of the adsorbent material is expressed in g / g.

[0099] The pore volume utilization rates of MCM-41-4.5 for adsorption of benzene-containing waste gas at a partial pressure of 30 mbar at multiple temperatures are shown in Table 4. Figure 9 As shown, the pore volume utilization rate at 5℃ can reach a maximum of 69.0% (dynamic saturated adsorption) and 59.5% (dynamic breakthrough adsorption). It should be emphasized that although under these adsorption pressure and temperature conditions, filled adsorption can be formed in most pores of the MCM-41-4.5 material, a small amount of non-VOCs (such as nitrogen) molecules occupy a certain volume during dynamic adsorption, resulting in the actual adsorption amount being lower than the theoretical total adsorption amount Q. t Too low, such as Figure 1 As shown, for the dynamic adsorption process, a pore volume utilization rate of 69.0% is close to the maximum adsorption capacity that the dynamic adsorption process can achieve, 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 benzene partial pressure of 30 mbar, at the adsorption temperature of 15℃, the suitable adsorption material should have the pore size less than and close to 5.96 nm. It can be found by the comparison of the pore volume utilization that the MCM-41-4.5 material with the pore size mainly distributed between 4.0-6.0 nm can keep the high pore volume utilization of 69.6% (dynamic saturated adsorption) and 60.9% (dynamic breakthrough adsorption).

[0101] According to equation (4), at the adsorption temperature of 45℃, the suitable adsorption material should have the pore size less than and close to 2.77 nm, however, the pore size of MCM-41-4.5 is mainly distributed between 4.0-6.0 nm, which cannot meet the pore size requirement of less than and close to 2.77 nm, therefore, the filling adsorption with high pore volume utilization cannot occur in the pores of MCM-41-4.5, and the covering adsorption with low pore volume utilization occurs mainly, resulting in the low pore volume utilization of 17.4% (dynamic saturated adsorption) and 14.3% (dynamic breakthrough adsorption).

[0102] In summary, the present application uses two or more model adsorption materials with concentrated pore size distribution, and according to the adsorption of VOCs on porous materials, the filling adsorption with high pore volume utilization occurs in the pores below a certain size, the matching relationship equation between the critical pore size of filling adsorption and the adsorption partial pressure, and the variation rule thereof with the adsorption temperature are explored. By normalizing the partial pressure with respect to the saturated vapor pressure at the respective adsorption temperature, the parameters related to the adsorption temperature (such as the saturated vapor pressure) are introduced into the equation as variables, so that the equation capable of solving the critical pore size applicable to the adsorption of VOCs with different temperatures and concentrations is obtained. Based on the equation, the critical pore size D C that can occur the filling adsorption with high pore volume utilization can be obtained when the adsorption temperature T and the critical relative pressure P C of the adsorbent are less than and close to the critical pore size D C , and the adsorbent should have the largest pore volume as possible. The effectiveness of the selection basis is verified by the dynamic adsorption test results. The adsorbent selection method for the industrial organic waste gas across the adsorption temperature is formed, which can provide the suitable pore size range and other reference basis 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, the most probable pore size is 4.0 nm, and the pore size is mainly distributed between 3.0-5.0 nm, as shown in Figure 10 The dynamic adsorption breakthrough curves of MCM-41-4.0 material at the corresponding adsorption temperature (5, 15, 25, 35, 45℃) for the benzene with partial pressure of 30 mbar are tested, as shown in Figure 11The test conditions are: flow rate is 20 ml / min, and the adsorbent dosage is 0.3 g. According to the time of dynamic adsorption breakthrough curve, combined with the flow rate of waste gas, the concentration of VOCs and the adsorbent dosage, the dynamic breakthrough adsorption amount of VOCs at a specific concentration and the dynamic saturated adsorption amount are calculated according to equation (3), as shown in Table 5. Table 5 Dynamic saturated adsorption amount (Q ds ) and dynamic breakthrough adsorption amount (Q dp ) of adsorbent MCM-41-4.0 for waste gas containing benzene with partial pressure of 30 mbar

[0105]

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

[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 rate of adsorbent MCM-41-4.0 at multiple temperatures is shown in Table 5 and Figure 12 It can be seen that the pore volume utilization rate at 5℃ can reach 70.0%, which is close to the maximum adsorption amount that can be achieved in the dynamic adsorption process, and close to the maximum pore volume utilization rate.

[0109] According to equation (4), for organic waste gas with benzene partial pressure of 30 mbar, at an adsorption temperature of 15℃, the suitable adsorbent should have a pore size less than and close to 5.96 nm. By comparing the pore volume utilization rate, it can be found that MCM-41-4.0 material with pore size mainly distributed between 3.0-5.0 nm can maintain a high pore volume utilization rate of 64.9% (dynamic saturated adsorption) and 59.6% (dynamic breakthrough adsorption), which verifies the effectiveness of the selection basis.

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

[0111] According to equation (4), for the organic waste gas with benzene partial pressure of 30 mbar, the suitable adsorbent material should have a pore size less than and close to 4.33 nm at an adsorption temperature of 25℃. The pore size of MCM-41-4.0 is mainly distributed between 3.0-5.0 nm, and most of the pores can meet the requirement of a pore size less than and close to 4.33 nm, and a small part of the pores is greater than 4.33 nm. Therefore, in the pores of MCM-41-4.0, the filling adsorption with high pore volume utilization can occur in most of the pores, and the covering adsorption with low pore volume utilization occurs in a part of the pores. Thus, the pore volume utilization of dynamic saturation adsorption can be maintained at a relatively high level of 59.6%, but the pore volume utilization of dynamic breakthrough adsorption is 40.3%, and there is a large difference between the dynamic saturation adsorption amount and the dynamic breakthrough adsorption amount, about 20%.

[0112] This is mainly due to the critical pore size D C . C is the critical pore size at which the filling adsorption can occur in the pores with a size less than D C and the covering adsorption occurs in the pores with a size greater than D C , and D C is the dividing line between the two. When the benzene partial pressure is 30 mbar and the adsorption temperature is 25℃, the critical pore size D C = 4.33 nm is located in the main region of the pore size distribution of MCM-41-4.0, 3.0-5.0 nm, resulting in that the adsorption force of the part of the pores located near the critical pore size D C = 4.33 nm has no surplus, and a large number of pores at the end of the adsorbent bed need to wait for the VOCs concentration to reach the corresponding value before the filling adsorption can continue to occur, thereby resulting in a significant reduction in the pore volume utilization of the dynamic breakthrough adsorption (40.3%) compared with that of the dynamic saturation adsorption (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 the critical pore size D Cwithin the range of 0.95 to 1.05, the more the pore volume, the better the pore size distribution should be, and the pore size distribution should be distributed in the critical pore size D C The following is to make the adsorbent material maintain a high utilization rate of pore volume for both dynamic saturation adsorption and dynamic breakthrough adsorption.

[0114] Example 3

[0115] The ordered mesoporous silica MCM-41 material with the series of most probable pore diameters of 3.0 nm, 4.0 nm and 4.5 nm in Example 1 was used as a model adsorbent. The static adsorption isotherms of the three model adsorbents for acetone at 5℃, 15℃, 25℃, 35℃ and 45℃ were tested by using an intelligent gravimetric analyzer (IGA), as shown in FIG. 1. Figure 13

[0116] By dividing each pressure point on the adsorption isotherm by the saturated vapor pressure at the corresponding temperature, the static adsorption isotherms after pressure normalization were obtained, as shown in FIG. 2. Figure 14 According to the normalized adsorption isotherms of the three model adsorbents (pore diameters of 3.0 nm, 4.0 nm and 4.5 nm) at five temperatures (5℃, 15℃, 25℃, 35℃ and 45℃), the middle points of the corresponding rapid rising stages (critical relative pressures P C / P0) when filling-type adsorption occurred were determined, as shown in Table 6.

[0117] Table 6 Values of the critical relative pressures (P C / P0) of the middle points of the corresponding rapid rising stages when filling-type adsorption occurred on the normalized adsorption isotherms

[0118]

[0119] According to the method of Example 1, 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, i.e., equation (1), can be obtained by linear fitting.

[0120] Based on the adsorption isotherms at different adsorption temperatures in the same pore diameter, by matching the middle points of the corresponding rapid rising stages (critical relative pressures P C / P0) when filling-type adsorption occurred at different adsorption temperatures with the adsorption temperature T, and performing linear fitting, it was found that the critical relative pressures of the adsorption isotherms at different temperatures in the same size pore presented a good linear relationship between the adsorption temperature. Linear relationship equations between the critical relative pressure (P C / P0) and the adsorption temperature (T) in different sizes of pores were obtained, and the linear fitting results are shown in FIG. 3. Figure 15 ​As shown, the linear relationship equations are as follows:

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

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

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

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

[0125] Table 7. Critical relative pressure (P) in orifices of different sizes. C The coefficients k and d in equation (1) relating / P0) to the adsorption temperature (T)

[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 measuring the critical relative pressure (P) in three different orifice sizes... C The coefficients k and d in the linear equation relating / P0) to adsorption temperature (T) were linearly fitted with respect to their respective pore sizes (3.0, 4.0, and 4.5 nm) to obtain the coefficients k and d as a function of the critical pore size D. C The linear relationship equation for the change is k = 0.00041 × D C +0.000253 and d = 0.118 × D C -0.227, such as Figure 16 As shown, the critical relative pressure (P) of the packed adsorption is thus obtained. C / P0) varies with adsorption temperature T and critical pore size D C The linear relationship equation of change:

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

[0129] This equation can be used to solve for the critical relative pressure P at different adsorption temperatures T that allow for packed adsorption. C / P0 and critical aperture DC the matching relationship between the critical relative pressure P C the critical relative pressure P C the matching relationship between the critical relative pressure P

[0130] the critical relative pressure P C the critical pore diameter D C the matching relationship between the critical relative pressure P

[0131] D C = (P C the critical relative pressure P

[0132] According to equation (9), when the acetone partial pressure is 100 mbar, the critical pore diameters corresponding to the filling adsorption that can occur at multiple adsorption temperatures (15, 25, 35, 45 °C) 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 a basis for selecting adsorbents under corresponding conditions.

[0133] Table 8 Critical pore diameters D C corresponding to the matching relationship between the critical relative pressure P

[0134] T / ℃ P (mbar) [P0] P C / P0]]> 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 acetone-containing waste gas with a partial pressure of 100 mbar, the appropriate pore diameter at 15 °C should be less than but close to 5.91 nm. Taking MCM-41-4.5 material as an example, its most probable pore diameter is 4.5 nm, and its pore diameters are mainly distributed between 4.0 and 6.0 nm, as shown in Figure 17 which meets the requirement of being less than and close to the critical pore diameter 5.91 nm calculated according to equation (9).

[0136] The dynamic adsorption breakthrough curves of MCM-41-4.5 material for 100 mbar acetone at corresponding adsorption temperatures (15, 25, 35, 45 °C) were tested, as shown in Figure 18 The test conditions were: flow rate of 20 ml / min, and adsorbent dosage of 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 the dynamic saturated adsorption capacity of VOCs at a specific concentration were calculated by equation (9), as shown in Table 9.

[0137] Table 9 Dynamic saturation adsorption and dynamic breakthrough adsorption of acetone at various adsorption temperatures on adsorbent MCM-41-4.5

[0138]

[0139] The total pore volume V of the adsorbent t and the density of acetone p, the theoretical total adsorption capacity Qt of MCM-41-4.5 was calculated according to equation (6) and equation (7) in Example 1, respectively t and the pore volume utilization rate η. The total pore volume of MCM-41-4.5 was 0.802 cm 3 / g, and the density of acetone was about 0.788 g / cm 3 The theoretical total adsorption capacity Qt of MCM-41-4.5 was calculated as follows t = p x V t = 0.802 cm 3 / g x 0.788 g / cm 3 = 0.632 g / g. Generally, this theoretical total adsorption capacity is close to the highest point of the static adsorption isotherm.

[0140] The pore volume utilization rate of MCM-41-4.5 for the adsorption of acetone-containing waste gas at a partial pressure of 100 mbar at various temperatures is shown in Table 9 and Figure 19 It can be seen that the pore volume utilization rate at 15°C can reach 60.1% (dynamic saturation adsorption) and 54.9% (dynamic breakthrough adsorption). It is emphasized that, due to the slightly poor regularity of acetone molecules compared with benzene, the pore volume utilization rate is slightly lower than that of benzene. Although under the conditions of this adsorption pressure and temperature, a filled adsorption can be formed in most of the pores of MCM-41-4.5, due to the occupation of a certain volume by a small amount of non-VOCs (such as nitrogen) molecules during the dynamic adsorption process, the actual adsorption capacity is slightly lower than the theoretical total adsorption capacity Qt. For the dynamic adsorption process, the pore volume utilization rate of 60.1% is close to the maximum adsorption capacity that can be achieved by the dynamic adsorption process, and is also close to the maximum value of the pore volume utilization rate.

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

[0142] According to equation (9), at an adsorption temperature of 45℃, the suitable adsorbent material should have a pore size smaller than and close to 2.66 nm. However, the pore size of MCM-41-4.5 is mainly distributed between 4.0-6.0 nm, which cannot meet the requirement of a pore size smaller than and close to 2.77 nm. Therefore, high pore volume utilization rate of packed adsorption cannot occur in the pores of MCM-41-4.5. Instead, low pore volume utilization rate of covered adsorption occurs, resulting in low pore volume utilization rates of 29.5% (dynamic saturated adsorption) and 23.6% (dynamic breakthrough adsorption). It should be noted that, since acetone molecules are more polar than benzene molecules, in the polar SiO2-based adsorbent material MCM-41, the more polar acetone molecules have a stronger interaction force with VOCs molecules during the covered adsorption process. Therefore, the adsorption capacity and pore volume utilization rate of covered adsorption are also greater. The above dynamic adsorption test results verify the effectiveness of the selection criteria.

[0143] Example 4

[0144] For MCM-41-4.0 material, its most probable pore size is 4.0 nm, and its pore size is mainly distributed between 3.0 and 5.0 nm. Figure 20 As shown. The dynamic adsorption breakthrough curves of MCM-41-4.0 material at the corresponding adsorption temperatures (15, 25, 35, 45℃) for acetone with a partial pressure of 100 mbar are shown below. Figure 21 As shown. Test conditions: flow rate of 20 ml / min, adsorbent dosage of 0.3 g. Based on the time of dynamic adsorption breakthrough curve, combined with the flow rate of waste gas, VOCs concentration and 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 adsorbent material MCM-41-4.0 for acetone-containing waste gas with a partial pressure of 100 mbar ds With dynamic breakthrough adsorption capacity Q dp

[0145]

[0146] Combined with the total pore volume V of the adsorbent material t Based on the density ρ of acetone, and according to equations (6) and (7) in Example 1, the theoretical total adsorption capacity Q of the MCM-41-4.0 material was calculated. t And the pore volume utilization rate η. The total pore volume of MCM-41-4.0 material is 0.831 cm³. 3 / g, the density of acetone is approximately 0.788g / cm³. 3 The theoretical total adsorption capacity Q was calculated. t =ρ×V t =0.831cm 3= 0.788 g / cm 3 = 0.655 g / g. The pore volume utilization of MCM-41-4.0 at various temperatures is shown in Table 10 and Figure 22 It can be seen that the pore volume utilization at 15°C can reach as high as 58.9%, which is close to the maximum adsorption capacity that can be achieved in a dynamic adsorption process, close to the maximum pore volume utilization.

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

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

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

[0150] Since the acetone molecule has a stronger polarity than benzene, in the polar SiO2 composed adsorbent MCM-41, the acetone molecule with stronger polarity has a stronger interaction force between the material and the VOCs molecule in the process of forming covering adsorption, therefore, the adsorption capacity of covering adsorption is greater.

[0151] Therefore, the application adopts the above-mentioned industrial organic waste gas adsorbent selection method across adsorption temperature and application, by taking the adsorption temperature T and the VOCs partial pressure as variables, the same equation can be used to obtain the critical pore diameter D corresponding to the high pore volume utilization rate of the packed adsorption under different adsorption temperatures and VOCs concentrations C . The critical pore diameter can be used as the basis for selecting the adsorbent. The effectiveness of the selection basis is verified by the dynamic adsorption test results. The selection of the adsorbent should be within the range less than and close to the critical pore diameter D C , with as much pore volume as possible, and the pore size range that contributes more to the pore volume should be distributed in the critical pore diameter D C . The following enables the adsorbent material to maintain a high pore volume utilization rate for both dynamic saturation adsorption and dynamic breakthrough adsorption.

[0152] In summary, the application uses two or more model adsorbents with concentrated pore size distribution, and according to the adsorption of VOCs on porous materials, high pore volume utilization rate of packed adsorption will be formed in pores below a certain size. The matching relationship equation between the critical pore diameter of packed adsorption and the adsorption partial pressure, and its variation with the adsorption temperature are explored. By normalizing the partial pressure with respect to the saturation vapor pressure at the respective adsorption temperature, the parameters related to the adsorption temperature (such as the saturation vapor pressure) are introduced into the equation as variables, thereby obtaining an equation that can solve the critical pore diameter applicable to the adsorption of VOCs with different temperatures and concentrations. Based on the equation, the critical pore diameter D C of the packed adsorption corresponding to the high pore volume utilization rate can be obtained when the adsorption temperature T and the critical relative pressure P C , and the selection of the adsorbent should be within the range less than and close to the critical pore diameter D C , with as much pore volume as possible. The industrial organic waste gas adsorbent selection method across adsorption temperature is formed, which can provide suitable pore size range reference for the development of high-efficiency adsorbent materials and technologies for VOCs with different concentrations at different temperatures.

[0153] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the application and not to limit them. Although the application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the application can still be modified or replaced by equivalents, and these modifications or replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the application.

Claims

1. A method for selecting an adsorbent for an industrial organic waste gas across an adsorption temperature, characterized by, The method comprises the following steps: (1) providing two or more porous materials with concentrated pore size distribution as model adsorbents, testing pore structure parameters, and testing static adsorption isotherms of the adsorbents 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, the intermediate point P of the corresponding fast-rising phase of the filling-type adsorption is determined C the corresponding normalized critical relative pressure P C / P0 value; (3) Linear fitting was performed on the critical relative pressure P C / P0 at different temperatures in the same pore size to obtain the linear relationship equation between the critical relative pressure P C / P0 and the adsorption temperature T. P C / P0 = k x 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 as the relative pressure approaches 0; (4) Based on equation (1), calculate the critical relative pressure P of a plurality of adsorbent materials with a concentrated pore size C linear relationship equation between P0 and adsorption temperature T, solve the coefficient k and d of the equation in the corresponding size of the hole; (5) the critical relative pressure P C k and d of the linear relationship equation between P / P0 and the adsorption temperature T, with respect to the respective critical pore diameter D C Linear fitting was performed to obtain the critical relative pressure P C of the filled adsorption of the linear relationship equation between P / P0 and the adsorption temperature T and the critical pore diameter D C ​ P C / P0 = (k1 x D C +k0) x T + (d1 x D C +d0) (2) In the formula, k1 and k0 are the slope and intercept of the function relationship k = f (D C ) = k1 x D C + k0, respectively, and d1 and d0 are the slope and intercept of the function relationship d = g (D C ) = d1 x D C + d0, respectively. (6) determining the suitable pore size range of the VOC adsorbent at different adsorption temperatures and VOC concentrations by equation (2), to provide a reference for the selection of model adsorbents; (7) verifying the selection of model adsorbents by equation (2).

2. The method for selecting an adsorbent for an industrial organic waste gas according to claim 1, wherein The number of the adsorbents with concentrated pore size distribution is greater than or equal to 2.

3. The method for selecting an adsorbent for an industrial organic waste gas according to claim 1, wherein The step (1) further comprises: Using the test of commercial specific surface area and pore structure analyzer, the pore structure parameters of the adsorbing material are obtained by the DFT cylindrical pore calculation model, the pore structure parameters including pore size distribution, total pore volume V t .

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

5. The method for selecting an adsorbent for an industrial organic waste gas according to claim 1, wherein The VOCs are one of hydrocarbon organic matter, oxygen-containing organic matter, halogen-containing organic matter, nitrogen-containing organic matter, and sulfur-containing organic matter.

6. The method for selecting an adsorbent for an industrial organic off-gas according to claim 1, wherein In the step (1), the number of the multiple adsorption temperatures is greater than or equal to 2.

7. The method of claim 1, wherein the method is characterized by: The selection of model adsorbents is verified by equation (2), and the specific process is as follows: First, the dynamic adsorption breakthrough curve of the model adsorbent for specific concentration of VOCs at different adsorption temperatures is tested, the breakthrough time and saturation time of the dynamic adsorption breakthrough curve are combined with the flow rate of the waste gas, the concentration of VOCs, and the amount of adsorbent to calculate the dynamic breakthrough adsorption amount and dynamic saturation adsorption amount of VOCs at a specific concentration; Then, the suitable pore size range of the VOC adsorbent at different temperatures obtained by equation (2) is combined with the pore size distribution of the adsorbent to calculate the pore volume utilization rate, and the accuracy of the obtained adsorbent selection basis is verified.

8. The application of the method for selecting adsorbents for industrial organic waste gas across adsorption temperatures according to any one of claims 1-7 in the treatment, recovery, and development of special adsorbents for VOCs.

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