Method for long-term efficiency prediction of adsorptive air filter elements

Abstract

The application provides a long-term efficiency prediction method for an adsorption type air filter element, and has the characteristics that the method comprises the following steps: step S1, dividing the adsorption type air filter element to obtain a plurality of unit bodies; step S2, calculating the outlet gas phase pollutant concentration of each unit body at an inlet section according to the inlet pollutant concentration of the adsorption type air filter element; step S3, sequentially calculating the outlet gas phase pollutant concentration of each unit body along the airflow direction to obtain the outlet gas phase pollutant concentration of each unit body at an outlet section; step S4, calculating the outlet pollutant concentration of the adsorption type air filter element at a current moment; and step S5, calculating the long-term efficiency prediction result of the adsorption type air filter element according to the inlet pollutant concentration and the outlet pollutant concentration of the adsorption type air filter element at each moment. In general, the method can more accurately predict the long-term efficiency of the adsorption type air filter element.

Description

Technical Field

[0001] This invention belongs to the field of air purification technology, specifically relating to a method for predicting the long-term efficiency of an adsorption-type air filter element. Background Technology

[0002] Currently, adsorption is the most common technology for removing volatile organic compounds (VOCs) from indoor environments, especially in residential buildings and cleanrooms in chip factories where VOC concentration limits are low. While there is considerable research on mass transfer models for adsorption air filter elements, it remains impossible to predict their long-term efficiency during the design phase. Therefore, designers of adsorption air filter elements lack reference points for material selection, structural design, maintenance cycles, and lifespan prediction, resulting in inconsistent purification effects when this technology is applied.

[0003] In their paper "Shaverdi G, Haghighat F, Ghaly W. Development and systematic validation of an adsorption filter model[J]. Building and Environment, 2014, 73: 64-74," Shaverdi et al. established a calculation model for the adsorption filter efficiency-time relationship under common operating conditions of adsorption filter elements. This model combines micropore diffusion and surface diffusion in the calculation and ignores the influence of adsorption heat on the equilibrium adsorption amount. In their paper "Pei JJ, Zhang J S. Modeling of sorbent-based gas filters: Development, verification and experimental validation[J]. Building Simulation, 2010, 3(1): 75-86," Pei and Zhang proposed an analytical model for adsorption filter efficiency.

[0004] However, existing methods for predicting the long-term efficiency of adsorption air filter elements still have the following shortcomings: the distribution coefficient is mainly calculated from the experimentally measured equilibrium adsorption capacity, but adsorption experiments at low concentrations are time-consuming and the calculation parameters are difficult to obtain; existing models do not involve the degree of reversibility of the adsorption process, but actual adsorption materials all have partial reversibility; existing models all assume that the adsorbent particles are spherical and that there is no contact or obstruction between the spheres, and the convective mass transfer coefficient calculated based on this may differ significantly from the actual value; the analytical model does not take into account the difference in oncoming wind speed caused by the front flow channel structure of the adsorption air filter element, which in turn affects the accuracy of the adsorption efficiency calculation. Summary of the Invention

[0005] This invention was made to solve the above-mentioned problems, and its purpose is to provide a method for predicting the long-term efficiency of adsorption-type air filter elements.

[0006] This invention provides a method for predicting the long-term efficiency of an adsorption air filter element, characterized by the following steps: Step S1, dividing the adsorption air filter element into multiple cross-sections perpendicular to the airflow direction based on its thickness, and then dividing it into multiple unit cells along the airflow direction based on the distribution of the oncoming wind speed; Step S2, using the inlet pollutant concentration of the adsorption air filter element as the inlet gas phase pollutant concentration C of each unit cell in the inlet cross-section of the adsorption air filter element. 气相 The outlet gaseous pollutant concentration C of each unit cell at the inlet section was calculated. 出口 Step S3: Set the outlet gaseous pollutant concentration C of the current cross-section unit. 出口 The inlet gaseous pollutant concentration C of the unit cell at the corresponding position of the next adjacent cross section along the airflow direction. 气相 The outlet gaseous pollutant concentration C of each unit in each cross section is calculated sequentially along the airflow direction. 出口 The outlet gas phase pollutant concentration C of each unit cell of the adsorption air filter element's outlet cross-section is obtained. 出口 Step S4: Based on the outlet gaseous pollutant concentration C of each unit at the outlet cross-section. 出口 The current pollutant concentration C at the outlet of the adsorption air filter element is calculated. 出口总浓度 Step S5: Based on the inlet and outlet pollutant concentrations C of the adsorption air filter element at each time point... 出口总浓度 The long-term efficiency prediction results of the adsorption air filter element were calculated, including the calculation of the outlet gas phase pollutant concentration C. 出口 The process includes the following sub-steps: Step T1, obtaining the volume V of the unit based on the volume of the adsorption-type air filter element and the unit division method. 单元体 Based on the mass and volume V of the adsorption material filled in the adsorption air filter element 单元体 The total mass M of the adsorbent material within the unit cell is obtained. 吸附材料 Step T2, based on the pore surface area S of the pore size where reversible adsorption of the adsorbent material mainly occurs. 可逆孔径 and the total surface area S of the adsorbent material 总 The proportion of reversible adsorption in the total amount of gaseous pollutant adsorbed by the adsorbent material is calculated and used as the reversible proportion r. 可逆 Step T3, based on the total mass M of the adsorbent material within the unit cell... 吸附材料 Unit volume V 单元体 Reversible ratio r可逆 Key aperture volume V 关键孔径 and the current inlet gaseous pollutant concentration C of the unit 气相 The invertibility coefficient K of the unit at the current time is calculated. 可逆 and the irreversible coefficient K 不可逆 Step T4, based on the inlet gaseous pollutant concentration C 气相 Reversible ratio r 可逆 Invertibility coefficient K 可逆 Irreversible coefficient K 不可逆 Macroscopic convective mass transfer resistance R, reversible equivalent concentration C 可逆 and irreversible equivalent concentration C 不可逆 The amount of pollutants entering the gas phase for irreversible adsorption at the current moment, ΔM, is calculated. 气相进入不可逆吸附量 The amount of pollutants entering the reversible adsorption capacity in the gas phase, ΔM 气相进入可逆吸附量 Step T5, based on the inlet gaseous pollutant concentration C 气相 The amount of pollutants entering the gas phase with irreversible adsorption ΔM 气相进入不可逆吸附量 The amount of pollutants entering the reversible adsorption capacity in the gas phase, ΔM 气相进入可逆吸附量 and unit volume V 单元体 The concentration C of gaseous pollutants at the outlet of the unit at the current moment is calculated. 出口 In step T3, the critical aperture volume V 关键孔径 The pore volume is the key pore size for the adsorption of pollutant gas molecules by the adsorption material of an adsorption-type air filter element.

[0007] The long-term efficiency prediction method for adsorption air filter elements provided by the present invention may also have the following feature: in step S1, the adsorption air filter element is divided along the airflow direction according to the velocity gradient distribution of the oncoming wind speed, and the difference in oncoming wind speed between adjacent units of the same cross section is controlled within 0.1 m / s.

[0008] The long-term efficiency prediction method for adsorption air filter elements provided by the present invention may also have the following features: wherein, in step S2, the inlet pollutant concentration at the current moment is obtained by: coupling calculation of the outlet pollutant concentration of the adsorption filter element at the previous moment and the mathematical model of the room and environment; or by actually measuring the inlet pollutant concentration of the adsorption filter element at the current moment; or by estimation.

[0009] The long-term efficiency prediction method for adsorption-type air filter elements provided by the present invention may also have the following feature: wherein, in step S4, the current outlet pollutant concentration C 出口总浓度 The calculation formula is as follows: In the formula C 出口单元体The current concentration C of gaseous pollutants at the outlet cross-section is... 出口 V 单元体风量 V represents the outflow air volume of this unit at the current moment. 总风量 This represents the total outflow volume of all units at the outlet section at the current moment.

[0010] The long-term efficiency prediction method for adsorption-type air filter elements provided by this invention may also have the following feature: In step S5, the long-term efficiency prediction result is composed of efficiency prediction results at various times, and the calculation formula for the efficiency prediction result at a single time is as follows: S 单个时刻 =(C 入口污染物 -C 出口总浓度 ) / C 入口污染物 *100%, where S is the formula 单个时刻 For the efficiency prediction result at this moment, C 入口污染物 This represents the concentration of pollutants entering the inlet at that moment.

[0011] The long-term efficiency prediction method for adsorption-type air filter elements provided by this invention may also have the following feature: wherein, in step T2, the reversible proportion r 可逆 The calculation formula is as follows: In the formula, a and b are constants determined by the type of adsorbent material and the weight of the pollutant.

[0012] The long-term efficiency prediction method for adsorption-type air filter elements provided by this invention may also have the following feature: wherein, in step T3, the reversibility coefficient K of the unit cell at the current time is... 可逆 and the irreversible coefficient K 不可逆 The calculation formula is as follows: In the formula, c, d, and e are constants determined by the type of adsorption material and the type of pollutant gas.

[0013] The long-term efficiency prediction method for adsorption air filter elements provided by this invention may also have the following feature: wherein, in step T4, the macroscopic convective mass transfer resistance R is obtained through the following process: at time 0, different R values ​​are input and the outlet pollutant concentration C of the adsorption air filter element is calculated. 出口总浓度 If the concentration of pollutants at the outlet is C 出口总浓度 If the initial efficiency matches, then the value of R is the macroscopic convective mass transfer resistance R, and the amount of pollutants entering the gas phase at the current moment through irreversible adsorption is ΔM. 气相进入不可逆吸附量 The amount of pollutants entering the reversible adsorption capacity in the gas phase, ΔM 气相进入可逆吸附量 The calculation formula is as follows: When hour, when At that time, ΔM 气相进入不可逆吸附量 =0, In the formula, Δt is the time step at the current moment, and C is the reversible equivalent concentration at time t+1. 可逆 and irreversible equivalent concentration C 不可逆 The calculation formula is as follows: In the formula C 可逆，t+1 The reversible equivalent concentration C at time t+1 可逆 C 不可逆，t+1 The reversible equivalent concentration C at time t+1 不可逆 M 可逆，t M represents the cumulative reversible total amount of adsorbed phase in the unit cell at time t. 不可逆，t ΔM represents the cumulative irreversible total amount of adsorbed phase in the unit cell at time t. 迁移量，t ΔM represents the amount of pollutants that transition from reversible adsorption to irreversible adsorption in the gas phase at time t. 气相进入可逆吸附量，t Let ΔM be the amount of pollutants entering the reversibly adsorbed phase in the gas phase at time t. 气相进入不可逆吸附量，t Let denot be the amount of pollutant entering the gas phase in irreversibly adsorbed form at time t, k be the migration rate coefficient obtained from the properties of the adsorbent material, and Δt be the time step at time t. When t = 0, the reversible equivalent concentration C is... 可逆 and irreversible equivalent concentration C 不可逆 All are 0.

[0014] The long-term efficiency prediction method for adsorption air filter elements provided by this invention may also have the following feature: wherein, at the initial primary efficiency of 0, the inlet pollutant concentration and outlet pollutant concentration C of the adsorption air filter element are... 出口总浓度 The calculation is as follows: Initial primary efficiency = (Inlet pollutant concentration - C) 出口总浓度 () / Inlet pollutant concentration * 100%.

[0015] The long-term efficiency prediction method for adsorption-type air filter elements provided by this invention may also have the following feature: wherein, in step T5, the current outlet gas phase pollutant concentration C 出口 The calculation formula is as follows:

[0016] The role and effect of invention

[0017] According to the long-term efficiency prediction method of the adsorption air filter element of the present invention, since the total mass M of the adsorption material in the unit cell... 吸附材料 Unit volume V 单元体 Reversible ratio r 可逆 Key aperture volume V 关键孔径and the current inlet gaseous pollutant concentration C of the unit 气相 The allocation coefficient K can be calculated relatively easily and quickly. 可逆 and K 不可逆 Introducing the parameter reversible ratio r 可逆 By incorporating the influence of the reversibility of the adsorption material into the adsorption process, the macroscopic convective mass transfer resistance R obtained from the initial one-time efficiency calculation is closer to the true value. The cell size is divided according to the difference in oncoming wind speed to reflect the different adsorption efficiencies at different positions of the filter element under the wind speed gradient, making the calculation results of adsorption efficiency more accurate. Therefore, the long-term efficiency prediction method of the adsorption air filter element of the present invention can more accurately predict the long-term efficiency of the adsorption air filter element. Attached Figure Description

[0018] Figure 1 This is a schematic diagram illustrating the principle of the long-term efficiency prediction method for adsorption air filter elements in an embodiment of the present invention.

[0019] Figure 2 This is a flowchart illustrating the long-term efficiency prediction method for adsorption-type air filter elements in an embodiment of the present invention.

[0020] Figure 3 This is a schematic diagram of dividing the adsorption-type air filter element into unit bodies in an embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram of dividing the adsorption-type air filter element into unit bodies when the oncoming wind speed is uniform in an embodiment of the present invention;

[0022] Figure 5 This is a schematic flowchart illustrating the calculation of outlet gaseous pollutant concentration in an embodiment of the present invention;

[0023] Figure 6 This is a schematic diagram of the mass transfer process in an embodiment of the present invention;

[0024] Figure 7 This is a schematic diagram comparing the long-term efficiency prediction results and measured values ​​of the activated carbon adsorption air filter element for adsorbing benzene vapor in an embodiment of the present invention. Detailed Implementation

[0025] To make the technical means, creative features, objectives and effects of this invention easy to understand, the following embodiments, in conjunction with the accompanying drawings, specifically illustrate the long-term efficiency prediction method of the adsorption air filter element of this invention.

[0026] Figure 1 This is a schematic diagram illustrating the principle of the long-term efficiency prediction method for adsorption-type air filter elements in an embodiment of the present invention.

[0027] like Figure 1As shown, this method mainly includes three calculation modules: a discretization calculation module for adsorption air filter elements, a gas-adsorption phase partition coefficient calculation module with the pore characteristics of the adsorption material as the key parameter, and a dynamic calculation module for the adsorption process of a unit cell with a ternary structure of gas-reversible adsorption capacity-irreversible adsorption capacity. The unit cell is divided according to the thickness of the adsorption air filter element and the oncoming wind speed gradient, and then the calculation is performed based on the pore characteristics of the adsorption material, i.e., S... 可逆孔径 and S 总 The distribution coefficient-concentration relationship function can be obtained by inversely proportionalizing r. 可逆 Therefore, based on the current gas phase concentration of the unit cell, i.e., the inlet gas phase pollutant concentration C... 气相 Calculate the real-time allocation coefficient, i.e., the invertible coefficient K. 可逆 and the irreversible coefficient K 不可逆 Based on this real-time distribution coefficient, the gas-phase reversible adsorption mass transfer rate and the gas-phase irreversible adsorption mass transfer rate are calculated, thereby obtaining the change in reversible adsorption, ΔM. 气相进入可逆吸附量 and the change in irreversible adsorption amount, i.e., ΔM 气相进入不可逆吸附量 Then, the unit outlet concentration, i.e., the outlet gaseous pollutant concentration C, is calculated. 出口 The cumulative value of the current adsorbed phase within the unit is used as the basis for calculating the real-time allocation coefficient at the next moment. The adsorption amount within the unit and the outlet concentration of the adsorption air filter element are calculated hourly based on the change in inlet concentration to obtain the efficiency of the adsorption air filter element at the current moment. Furthermore, by coupling calculation with the mathematical model of the room and environment, the inlet concentration can be updated, and thus long-term efficiency prediction results can be continuously simulated.

[0028] In this embodiment, taking the Amway Atmosphere Air Purifier 101076CH as an example, the adsorption air filter element is the filter screen of the Amway Atmosphere Air Purifier 101076CH. This adsorption air filter element is placed in an air duct for testing. The upstream of the air duct is connected to an experimental chamber that periodically emits benzene vapor. The thickness of the adsorption air filter element is 19mm, and the length and width of its windward face are 50cm and 25cm respectively. The adsorption material of the adsorption air filter element is activated carbon, with a migration rate coefficient k of 0.15. The total mass of the adsorption material is 1277g. 关键孔径 =0.0465cm 3 / g, the adsorption air filter element was placed in a horizontal airflow duct for adsorption testing. The adsorbed pollutant was benzene vapor, with a benzene vapor concentration in the range of 0-6 ppm. The inlet pollutant concentration was the actual measured value. Based on the actual measured value of the filter of Amway Atmosphere Air Purifier 101076CH in the range of 0-6 ppm benzene vapor concentration, the initial primary efficiency was calculated to be 37.6%.

[0029] Figure 2This is a schematic flowchart of the long-term efficiency prediction method for adsorption air filter elements in an embodiment of the present invention.

[0030] like Figure 2 As shown, the long-term efficiency prediction method for adsorption air filter elements in the embodiments of the present invention, namely the adsorption air filter element discretization calculation module, includes the following steps:

[0031] Step S1: Based on the thickness of the adsorption air filter element, divide the adsorption air filter element into multiple sections along the vertical direction of the airflow direction. Then, based on the distribution of the oncoming wind speed of the adsorption air filter element, divide the adsorption air filter element into multiple units along the airflow direction.

[0032] In this process, the adsorption-type air filter element is divided along the airflow direction based on the velocity gradient distribution of the oncoming wind speed. The difference in oncoming wind speed between adjacent units with the same cross-section is controlled within 0.1 m / s. By dividing the areas with large wind speed variations into more detailed sections, the difference in oncoming wind speed in each area is kept within a certain range, which improves the accuracy of subsequent calculation results.

[0033] Figure 3 This is a schematic diagram of dividing the adsorption-type air filter element into unit bodies in an embodiment of the present invention.

[0034] like Figure 3 As shown, the entire cube is the adsorption air filter element, and the wind direction is the airflow direction. The adsorption air filter element is divided into multiple cross sections by the direction perpendicular to the airflow direction. The cross section in the direction of the wind inlet is called the inlet cross section, and the cross section in the direction of the wind outlet is called the outlet cross section. According to the distribution of the oncoming wind speed at the inlet cross section, the cross section is divided into units of different sizes.

[0035] Figure 4 This is a schematic diagram of dividing the adsorption-type air filter element into unit bodies when the oncoming wind speed is uniform in an embodiment of the present invention.

[0036] like Figure 4 As shown, the oncoming wind speed is uniform in this embodiment. Therefore, after dividing the adsorption filter element into 19 sections according to the thickness, each section can be regarded as a unit, resulting in a total of 19 units. The unit at the wind inlet is the inlet section, and the unit at the wind outlet is the outlet section.

[0037] Step S2, the inlet pollutant concentration of the adsorption air filter element is used as the inlet gas phase pollutant concentration C of each unit of the inlet cross-section of the adsorption air filter element. 气相 The outlet gaseous pollutant concentration C of each unit cell at the inlet section was calculated. 出口 .

[0038] The current inlet pollutant concentration can be obtained in several ways: by coupling the outlet pollutant concentration of the adsorption filter element at the previous moment with the mathematical model of the room and environment; or by actually measuring the inlet pollutant concentration of the adsorption filter element at the current moment; or by estimation. In this embodiment, the inlet pollutant concentration is obtained by actual measurement.

[0039] Step S3, set the outlet gaseous pollutant concentration C of the current cross-section unit cell. 出口 The inlet gaseous pollutant concentration C of the unit cell at the corresponding position of the next adjacent cross section along the airflow direction. 气相 The outlet gaseous pollutant concentration C of each unit in each cross section is calculated sequentially along the airflow direction. 出口 The outlet gas phase pollutant concentration C of each unit cell of the adsorption air filter element's outlet cross-section is obtained. 出口 .

[0040] Figure 5 This is a schematic diagram of the process for calculating the concentration of gaseous pollutants at the outlet in an embodiment of the present invention.

[0041] like Figure 5 As shown, calculate the outlet gaseous pollutant concentration C. 出口 Includes the following sub-steps:

[0042] Step T1: Based on the volume of the adsorption-type air filter element and the unit cell division method, obtain the volume V of the unit cell. 单元体 Based on the mass and volume V of the adsorption material filled in the adsorption air filter element 单元体 The total mass M of the adsorbent material within the unit cell is obtained. 吸附材料 In this embodiment, the 19 unit cells are all the same size, so the volume V of each unit cell is... 单元体 Each unit is 125 cubic centimeters. The adsorbent material within the adsorption-type air filter element is evenly distributed. Therefore, the M of each unit... 吸附材料 Both are 67.2g.

[0043] Step T2, based on the pore surface area S of the pore size where reversible adsorption of the adsorbent material mainly occurs. 可逆孔径 and the total surface area S of the adsorbent material 总 The proportion of reversible adsorption in the total amount of gaseous pollutant adsorbed by the adsorbent material is calculated and used as the reversible proportion r. 可逆 .

[0044] Among them, the reversible proportion r 可逆 The calculation formula is as follows:

[0045]

[0046] In the formula, a and b are constants determined by the type of adsorbent material and the weight of the pollutant.

[0047] In this embodiment, based on the adsorption material being activated carbon and the pollutant being benzene vapor, we obtain a = 0.564, b = 0.19, and S 可逆孔径 =71.11m 2 / g, S 总 =338.7m 2 / g, then The reversible ratio r of activated carbon adsorption of benzene at low concentrations was calculated. 可逆 =0.067.

[0048] Step T3, based on the total mass M of the adsorbent material within the unit cell 吸附材料 Unit volume V 单元体 Reversible ratio r 可逆 Key aperture volume V 关键孔径 and the current inlet gaseous pollutant concentration C of the unit 气相 The invertibility coefficient K of the unit at the current time is calculated. 可逆 and the irreversible coefficient K 不可逆 Key aperture volume V 关键孔径 The pore volume is the key pore size for the adsorption of pollutant gas molecules by the adsorption material of an adsorption-type air filter element.

[0049] Wherein, the invertibility coefficient K of the unit at the current time 可逆 and the irreversible coefficient K 不可逆 The calculation formula is as follows:

[0050]

[0051]

[0052] In the formula, c, d, and e are constants determined by the type of adsorption material and the type of pollutant gas.

[0053] In this embodiment, based on the adsorption material being activated carbon and the pollutant gas being benzene vapor, c = 9.8, d = 2.8, and e = 0.96 were obtained.

[0054] Steps T1 to T3 involve the gas-adsorption phase partition coefficient calculation module, which uses the pore characteristics of the adsorbent material as a key parameter. This is achieved by calculating the pore surface area S, which is the pore size at which reversible adsorption mainly occurs, based on the characteristics of the adsorbent material. 可逆孔径 and the total surface area S of the adsorbent material 总 The distribution coefficient-concentration relationship function can be calculated to obtain the inverse proportionality r. 可逆 Then, combined with the gas phase concentration, i.e., the inlet gas phase pollutant concentration C 气相 The real-time allocation coefficients and inverse coefficients K can be calculated. 可逆and the irreversible coefficient K 不可逆 .

[0055] Figure 6 This is a schematic diagram of the mass transfer process in an embodiment of the present invention.

[0056] like Figure 6 As shown, the concentration C of gaseous pollutants flowing into the unit cell, i.e., the inlet gaseous pollutant concentration. 气相 The convective mass transfer resistance, i.e., the macroscopic convective mass transfer resistance R, is divided into the amount of pollutants entering the gas phase that are irreversibly adsorbed, ΔM. 气相进入不可逆吸附量 The amount of pollutants entering the reversible adsorption capacity in the gas phase, ΔM 气相进入可逆吸附量 At this point, ΔM in the reversible portion of the adsorbed phase 迁移量，t The adsorbed phase migrates unidirectionally to the irreversible portion of the adsorbed phase, and the cumulative reversible amount M in the total amount of adsorbed phase of the unit cell at that moment can then be calculated. 可逆，t and cumulative irreversible total M 不可逆，t Finally, the outlet gas phase pollutant concentration C is obtained from the gas phase outflow unit. 出口 , where ΔM 气相进入不可逆吸附量 It cannot be negative, ΔM 气相进入可逆吸附量 It can be a negative value.

[0057] Step T4, based on the inlet gaseous pollutant concentration C 气相 Reversible ratio r 可逆 Invertibility coefficient K 可逆 Irreversible coefficient K 不可逆 Macroscopic convective mass transfer resistance R, reversible equivalent concentration C 可逆 and irreversible equivalent concentration C 不可逆 The amount of pollutants entering the gas phase for irreversible adsorption at the current moment, ΔM, is calculated. 气相进入不可逆吸附量 The amount of pollutants entering the reversible adsorption capacity in the gas phase, ΔM 气相进入可逆吸附量 .

[0058] The macroscopic convective mass transfer resistance R is obtained through the following process:

[0059] At time 0, input different R values ​​and calculate the outlet pollutant concentration C of the adsorption air filter element. 出口总浓度 If the concentration of pollutants at the outlet is C 出口总浓度 If the initial primary efficiency matches, then the value of R is the macroscopic convective mass transfer resistance R, and the inlet and outlet pollutant concentrations C of the adsorption air filter element are at the moment when the initial primary efficiency is 0. 出口总浓度 The calculation is as follows: Initial primary efficiency = (Inlet pollutant concentration - C) 出口总浓度 () / Inlet pollutant concentration * 100%.

[0060] In this embodiment, based on an initial primary efficiency of 37.6% and uniform oncoming wind speed, the macroscopic convective mass transfer resistance R = 20.4 min can be obtained. -1 .

[0061] The amount of pollutants that enter the gas phase at the current moment with irreversible adsorption ΔM 气相进入不可逆吸附量 The amount of pollutants entering the reversible adsorption capacity in the gas phase, ΔM 气相进入可逆吸附量 The calculation formula is as follows:

[0062] when hour,

[0063]

[0064]

[0065] when hour,

[0066] ΔM 气相进入不可逆吸附量 =0,

[0067]

[0068] In the formula, Δt is the time step at the current moment.

[0069] The reversible equivalent concentration C at time t+1 可逆 and irreversible equivalent concentration C 不可逆 The calculation formula is as follows:

[0070]

[0071]

[0072]

[0073]

[0074]

[0075] In the formula C 可逆，t+1 The reversible equivalent concentration C at time t+1 可逆 C 不可逆，t+1 The reversible equivalent concentration C at time t+1 不可逆 M 可逆，t M represents the cumulative reversible total amount of adsorbed phase in the unit cell at time t. 不可逆，t ΔM represents the cumulative irreversible total amount of adsorbed phase in the unit cell at time t. 迁移量，t ΔM represents the amount of pollutants that transition from reversible adsorption to irreversible adsorption in the gas phase at time t. 气相进入可逆吸附量，t Let ΔM be the amount of pollutants entering the reversibly adsorbed phase in the gas phase at time t.气相进入不可逆吸附量，t Let denot be the amount of pollutant entering the gas phase in irreversibly adsorbed form at time t, k be the migration rate coefficient obtained from the properties of the adsorbent material, and Δt be the time step at time t. When t = 0, the reversible equivalent concentration C is... 可逆 and irreversible equivalent concentration C 不可逆 All are 0.

[0076] Step T5, based on the inlet gaseous pollutant concentration C 气相 The amount of pollutants entering the gas phase with irreversible adsorption ΔM 气相进入不可逆吸附量 The amount of pollutants entering the reversible adsorption capacity in the gas phase, ΔM 气相进入可逆吸附量 and unit volume V 单元体 The concentration C of gaseous pollutants at the outlet of the unit at the current moment is calculated. 出口 .

[0077] Among them, the current outlet gaseous pollutant concentration C 出口 The calculation formula is as follows:

[0078]

[0079] Steps T4 and T5, namely the dynamic calculation module for the adsorption process of the unit cell in the ternary structure of gas phase-reversible adsorption amount-irreversible adsorption amount, are performed using the reversibility coefficient K. 可逆 and the irreversible coefficient K 不可逆 The amount of pollutants ΔM entering the gas phase through irreversible adsorption was calculated. 气相进入不可逆吸附量 The amount of pollutants entering the reversible adsorption capacity in the gas phase, ΔM 气相进入可逆吸附量 Then, the outlet concentration of the unit cell, i.e., the outlet gaseous pollutant concentration C, is calculated. 出口 The cumulative amount of adsorbed phase, i.e. and

[0080] Step S4, based on the outlet gaseous pollutant concentration C of each unit cell at the outlet cross-section 出口 The current pollutant concentration C at the outlet of the adsorption air filter element is calculated. 出口总浓度 .

[0081] Among them, the current export pollutant concentration C 出口总浓度 The calculation formula is as follows:

[0082]

[0083] In the formula C 出口单元体 The current concentration C of gaseous pollutants at the outlet cross-section is... 出口 V 单元体风量 V represents the outflow air volume of this unit at the current moment. 总风量 This represents the total outflow volume of all units at the outlet section at the current moment.

[0084] Step S5, based on the inlet and outlet pollutant concentrations C of the adsorption air filter element at each time point. 出口总浓度 The long-term efficiency prediction results of the adsorption air filter element were calculated.

[0085] In step S5, the long-term efficiency prediction result is composed of the efficiency prediction results at each time point. The calculation formula for the efficiency prediction result at a single time point is as follows:

[0086] S 单个时刻 =(C 入口污染物 -C 出口总浓度 ) / C 入口污染物 *100%

[0087] In the formula S 单个时刻 For the efficiency prediction result at this moment, C 入口污染物 This represents the concentration of pollutants entering the inlet at that moment.

[0088] Figure 7 This is a schematic diagram comparing the long-term efficiency prediction results and measured values ​​of the activated carbon adsorption air filter element for adsorbing benzene vapor in an embodiment of the present invention.

[0089] like Figure 7 As shown, the horizontal axis represents the time for pollutant adsorption in minutes, and the vertical axis represents efficiency. The actual measured adsorption efficiency curve and the calculated efficiency prediction curve are shown. Over a long period of time, the calculated efficiency curve closely matches the measured efficiency curve. Furthermore, when the measured efficiency is negative or shows a downward trend, the corresponding calculated efficiency value is still close to the measured efficiency value. Therefore, the calculated efficiency curve can reflect the long-term efficiency trend when there is negative efficiency and a decrease in adsorption efficiency.

[0090] The role and effect of the embodiments

[0091] According to the long-term efficiency prediction method for adsorption-type air filter elements involved in this embodiment, the total mass M of the adsorption material within the unit is used to predict the efficiency. 吸附材料 Unit volume V 单元体 Reversible ratio r 可逆 Key aperture volume V 关键孔径 and the current inlet gaseous pollutant concentration C of the unit 气相 The allocation coefficient K can be calculated relatively easily and quickly. 可逆 and K 不可逆 Introducing a reversible proportional r 可逆This method incorporates the reversibility of the adsorption material into the adsorption process, and the macroscopic convective mass transfer resistance R calculated based on the initial primary efficiency more closely matches the actual value. Furthermore, by dividing the cell size according to the difference in oncoming wind speed, it reflects the different adsorption efficiencies at different locations of the filter element under wind speed gradients, making the calculated adsorption efficiency more accurate. In summary, this method can more accurately predict the long-term efficiency of adsorption-type air filter elements.

[0092] The above embodiments are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention.

Claims

1. A method for predicting the long-term efficiency of an adsorption-type air filter element, characterized in that, Includes the following steps: Step S1: Based on the thickness of the adsorption air filter element, divide the adsorption air filter element into multiple cross sections along the vertical direction of the airflow direction. Then, based on the distribution of the oncoming wind speed of the adsorption air filter element, divide the adsorption air filter element into multiple unit bodies along the airflow direction. Step S2, the inlet pollutant concentration of the adsorption air filter element is used as the inlet gas phase pollutant concentration C of each unit of the inlet cross-section of the adsorption air filter element. 气相 The outlet gaseous pollutant concentration C of each unit of the inlet section is calculated. 出口 ; Step S3, set the outlet gaseous pollutant concentration C of the unit cell at the current cross-section. 出口 The inlet gaseous pollutant concentration C is the unit cell at the corresponding position of the next adjacent cross section along the airflow direction. 气相 The outlet gaseous pollutant concentration C of each unit in each cross section is calculated sequentially along the airflow direction. 出口 The outlet gas phase pollutant concentration C of each unit of the adsorption air filter element is obtained. 出口 ; Step S4, based on the outlet gaseous pollutant concentration C of each unit of the outlet cross-section. 出口 The outlet pollutant concentration C of the adsorption air filter element at the current moment is calculated. 出口总浓度 ; Step S5, based on the inlet pollutant concentration and the outlet pollutant concentration C of the adsorption air filter element at each time point. 出口总浓度 The long-term efficiency prediction results of the adsorption-type air filter element were calculated. Among them, the concentration C of the gaseous pollutants at the outlet is calculated. 出口 Includes the following sub-steps: Step T1: Based on the volume of the adsorption-type air filter element and the unit division method, obtain the volume V of the unit. 单元体 Based on the mass of the adsorbent material filled in the adsorption air filter element and the volume V 单元体 The total mass M of the adsorbent material within the unit cell is obtained. 吸附材料 ; Step T2, based on the pore surface area S of the pore size where reversible adsorption of the adsorbent material mainly occurs. 可逆孔径 and the total surface area S of the adsorbent material 总 The proportion of reversible adsorption amount in the total amount of gaseous pollutant adsorbed by the adsorbent material is calculated and used as the reversible proportion r. 可逆 ; Step T3, based on the total mass M of the adsorbent material within the unit cell 吸附材料 The unit volume V 单元体 The reversible ratio r 可逆 Key aperture volume V 关键孔径 and the current inlet gaseous pollutant concentration C of the unit. 气相 The reversibility coefficient K of the unit body at the current time is calculated. 可逆 and the irreversible coefficient K 不可逆 ; Step T4, based on the inlet gaseous pollutant concentration C 气相 The reversible ratio r 可逆 The reversibility coefficient K 可逆 The irreversible coefficient K 不可逆 Macroscopic convective mass transfer resistance R, reversible equivalent concentration C 可逆 and irreversible equivalent concentration C 不可逆 The amount of pollutants entering the gas phase for irreversible adsorption at the current moment, ΔM, is calculated. 气相进入不可逆吸附量 The amount of pollutants entering the reversible adsorption capacity in the gas phase, ΔM 气相进入可逆吸附量 ; Step T5, based on the inlet gaseous pollutant concentration C 气相 The amount of pollutants ΔM that enters the gas phase through irreversible adsorption. 气相进入不可逆吸附量 The amount of pollutants ΔM entering the reversible adsorption phase in the gas phase. 气相进入可逆吸附量 and the unit volume V 单元体 The concentration C of the gaseous pollutant at the outlet of the unit at the current time is calculated. 出口 , In step T3, the critical aperture volume V 关键孔径 The pore volume is the key pore size of the adsorption material of the adsorption air filter element for the adsorption of gas molecules of the pollutants.

2. The method for predicting the long-term efficiency of an adsorption-type air filter element according to claim 1, characterized in that: in, In step S1, the adsorption-type air filter element is divided along the airflow direction according to the velocity gradient distribution of the oncoming wind speed, and the difference in oncoming wind speed between adjacent units with the same cross section is controlled within 0.1 m / s.

3. The method for predicting the long-term efficiency of an adsorption-type air filter element according to claim 1, Its features are: In step S2, the method for obtaining the current inlet pollutant concentration includes: The concentration of pollutants at the outlet of the adsorption filter element at the previous moment is obtained by coupling calculation with the mathematical model of the room and environment; or The inlet pollutant concentration of the adsorption filter element is actually measured at the current moment; or It was obtained through estimation.

4. The method for predicting the long-term efficiency of an adsorption-type air filter element according to claim 1, characterized in that: in, In step S4, the current outlet pollutant concentration C 出口总浓度 The calculation formula is as follows: In the formula C 出口单元体 The current concentration C of gaseous pollutants at the outlet cross-section is... 出口 V 单元体风量 V represents the outflow air volume of this unit at the current moment. 总风量 This represents the total outflow volume of all units at the outlet section at the current moment.

5. The method for predicting the long-term efficiency of an adsorption-type air filter element according to claim 1, characterized in that: in, In step S5, the long-term efficiency prediction result is composed of the efficiency prediction results at each time point. The calculation formula for the efficiency prediction result at a single time point is as follows: S 单个时刻 =(C 入口污染物 -C 出口总浓度 ) / C 入口污染物 *100%, In the formula S 单个时刻 For the efficiency prediction result at this moment, C 入口污染物 This represents the concentration of pollutants entering the inlet at that moment.

6. The method for predicting the long-term efficiency of an adsorption-type air filter element according to claim 1, characterized in that: in, In step T2, the reversible ratio r 可逆 The calculation formula is as follows: In the formula, a and b are constants determined by the type of adsorbent material and the weight of the pollutant.

7. The method for predicting the long-term efficiency of an adsorption-type air filter element according to claim 1, characterized in that: in, In step T3, the reversibility coefficient K of the unit body at the current time is... 可逆 and the irreversible coefficient K 不可逆 The calculation formula is as follows: In the formula, c, d, and e are constants determined by the type of adsorption material and the type of pollutant gas.

8. The method for predicting the long-term efficiency of an adsorption-type air filter element according to claim 1, characterized in that: in, In step T4, the macroscopic convective mass transfer resistance R is obtained through the following process: At time 0, input different R values ​​and calculate the outlet pollutant concentration C of the adsorption air filter element. 出口总浓度 If the concentration of the pollutant at the outlet is C 出口总浓度 If the efficiency matches the initial one-time efficiency, then the value of R is the macroscopic convective mass transfer resistance R. The amount of pollutants that enter the gas phase at the current moment with irreversible adsorption ΔM 气相进入不可逆吸附量 The amount of pollutants entering the reversible adsorption capacity in the gas phase, ΔM 气相进入可逆吸附量 The calculation formula is as follows: when hour, when hour, ΔM 气相进入不可逆吸附量 = 0, In the formula, Δt is the time step at the current moment. The reversible equivalent concentration C at time t+1 可逆 and the aforementioned irreversible equivalent concentration C 不可逆 The calculation formula is as follows: In the formula C 可逆，t+1 The reversible equivalent concentration C at time t+1 可逆 C 不可逆，t+1 The reversible equivalent concentration C at time t+1 不可逆 M 可逆，t M represents the cumulative reversible total amount of the adsorbed phase in the unit cell at time t. 不可逆，t ΔM is the cumulative irreversible total amount of the adsorbed phase in the unit cell at time t. 迁移量，t ΔM represents the amount of pollutants that transition from reversible adsorption to irreversible adsorption in the gas phase at time t. 气相进入可逆吸附量，t Let ΔM be the amount of pollutants entering the reversibly adsorbed phase in the gas phase at time t. 气相进入不可逆吸附量，t denoted by Δt, represents the amount of pollutants that irreversibly adsorb into the gas phase at time t; k is the migration rate coefficient, obtained from the properties of the adsorbent material; and Δt is the time step at time t. When t = 0, the reversible equivalent concentration C 可逆 and the aforementioned irreversible equivalent concentration C 不可逆 All are 0.

9. The method for predicting the long-term efficiency of an adsorption-type air filter element according to claim 8, characterized in that: in, At the initial primary efficiency of 0, the inlet pollutant concentration and outlet pollutant concentration C of the adsorption air filter element 出口总浓度 The calculation is as follows: Initial primary efficiency = (inlet pollutant concentration - C) 出口总浓度 () / Inlet pollutant concentration * 100%.

10. The method for predicting the long-term efficiency of an adsorption-type air filter element according to claim 1, characterized in that: in, In step T5, the current concentration C of the outlet gaseous pollutant is... 出口 The calculation formula is as follows:

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