CN-122024867-A - Prediction method and system for competitive adsorption saturation of multiple pollutants on activated carbon

CN122024867ACN 122024867 ACN122024867 ACN 122024867ACN-122024867-A

Abstract

The invention discloses a method and a system for predicting competitive adsorption saturation of multiple pollutants on active carbon, wherein the method comprises the steps of inputting basic parameters and Langmuir adsorption parameters of an active carbon adsorption box; according to the dominant pore size and the common pore size of each pollutant, calculating the dominant pore size correction coefficient of each pollutant, introducing the dominant pore size correction coefficient into a Langmuir competitive adsorption model, establishing a corrected competitive adsorption model, dispersing an activated carbon adsorption box into grid units, calling the corrected competitive adsorption model, carrying out iterative calculation on a time sequence according to the inlet concentration of each pollutant, langmuir adsorption parameters and adsorbent related parameters, and calculating the adsorption phase concentration and the adsorbent concentration of the position of each grid unit at different times to obtain the three-dimensional distribution of the saturation degree of the activated carbon along with the time. The method can be used for predicting and evaluating the spatial distribution of the saturation condition of simultaneously adsorbing various pollutants in the activated carbon adsorption device.

Inventors

GUO SHANSHAN
Zhuo Wenliu
CHEN XIONGBO
LIU YING
CHEN GEXIANG
YANG XIA

Assignees

生态环境部华南环境科学研究所(生态环境部生态环境应急研究所)

Dates

Publication Date: 20260512
Application Date: 20251217

Claims (10)

1. A method for predicting competitive adsorption saturation of multiple contaminants on activated carbon, the method comprising: inputting basic parameters and Langmuir adsorption parameters of an activated carbon adsorption box; determining the corresponding pore volume of the dominant adsorption pore diameter range of each pollutant, calculating the dominant pore diameter correction coefficient of each pollutant, introducing the dominant pore diameter correction coefficient into the Langmuir competitive adsorption model, and establishing a corrected competitive adsorption model; Dispersing the activated carbon adsorption box into grid units, calling a corrected competitive adsorption model, carrying out iterative calculation on a time sequence according to the inlet concentration of each pollutant, the Langmuir adsorption parameter and the relevant parameters of the adsorbent, and calculating the adsorption phase concentration and the adsorption mass concentration of the position of each grid unit at different times to obtain the three-dimensional distribution of the saturation degree of the activated carbon along with the time.
2. The prediction method according to claim 1, wherein the Langmuir adsorption parameter is calculated by a Langmuir competitive adsorption model, and the formula is as follows: ; wherein ai and bi are Langmuir adsorption parameters of the component i, C e,i is the equilibrium adsorption concentration of the component i, and q e,i is the equilibrium adsorption phase concentration of the component i under C e,i .
3. The method of claim 1, wherein the determining the dominant adsorption pore size range for each contaminant corresponds to pore volume, and calculating a dominant pore size correction factor for each contaminant is calculated by the formula: ; ; Wherein A i is the pore set adsorbed by component i, V Ai is the volume of pore set A i adsorbed by dominant component i, and ηi is the dominant pore size correction factor of component i.
4. The prediction method according to claim 1, wherein the dominant pore size correction coefficient is introduced into a Langmuir competitive adsorption model, and a corrected competitive adsorption model is established, wherein the formula is as follows: ; ; Wherein, the For the concentration of the adsorption phase of component i at the core of the granule, ai, bi are the Langmuir adsorption parameters of component i, Ηi is the dominant pore size correction coefficient for component i and C i is the adsorbate concentration for component i.
5. The method of claim 1-4, wherein the base parameters include geometry, gas flow rate at each location, initial concentration of exhaust gas, adsorbent bed thickness, adsorbent bed porosity, temperature, barometric pressure, activated carbon particle diameter, gas phase kinetic viscosity coefficient, gas phase density, adsorbent bed density, activated carbon particle porosity, molecular mass of each component, atomic diffusion volume of each component.
6. The method according to claim 5, wherein the calculating the adsorption phase concentration and the adsorption mass concentration at different times for each grid cell according to the inlet concentration of each contaminant, the Langmuir adsorption parameter, and the adsorbent-related parameter comprises: and (3) balancing the gas phase and solid phase mass of the infinitesimal in the one-dimensional axial plug flow model, wherein the following formula is as follows: ; Wherein, the , K L,i is the LDF total mass transfer coefficient of component i, C 0,i is the inlet concentration of component i, C i is the adsorbate concentration of component i, For the adsorption phase concentration of component i at the particle core, q i is the adsorption phase concentration of component i, q 0,i is the adsorption phase concentration of component i at the concentration of C 0,i , t is time, z is axial distance, D m,i is the molecular diffusion coefficient of component i, D L,i is the axial diffusion coefficient of component i, D p is the activated carbon particle diameter, ε p is the activated carbon particle porosity, τ p is the activated carbon particle bending coefficient, ρ is the adsorbent bed density; and calculating the molecular diffusion coefficient, wherein the molecular diffusion coefficient is calculated by the following formula: ; Wherein, (Σv) i is the atomic diffusion volume of component i, (Σv) g is the atomic diffusion volume of air, P is the atmospheric pressure, M i is the molecular mass of component i, M g is the molecular mass of air; and calculating the axial diffusion coefficient, wherein the axial diffusion coefficient is calculated by the following formula: ; Wherein, the , Re is the Reynolds number, sc is the Schmidt number, u is the apparent gas velocity, v is the kinematic viscosity of the gas, ε is the adsorbent bed porosity, ε 0 is the term corresponding to the stagnation contribution of axial diffusion.
7. The method according to claim 6, wherein the boundary conditions and initial conditions of the gas phase and solid phase mass balance of the microelements in the one-dimensional axial plug flow model are respectively as follows: ; ; Wherein L is the thickness of the adsorption bed layer.
8. A predictive system for competitive adsorption saturation of multiple contaminants on activated carbon, the system comprising: the parameter input module is used for inputting basic parameters and Langmuir adsorption parameters of the activated carbon adsorption box; The model building module is used for calculating dominant pore diameter correction coefficients of all pollutants according to the dominant pore diameter volume and the common pore diameter volume of all pollutants, introducing the dominant pore diameter correction coefficients into the Langmuir competitive adsorption model, and building a corrected competitive adsorption model; The prediction module is used for dispersing the activated carbon adsorption box into grid cells, calling a corrected competitive adsorption model, carrying out iterative calculation on time sequences according to the inlet concentration of each pollutant, the Langmuir adsorption parameter and the adsorbent related parameter, and calculating the adsorption phase concentration and the adsorbent concentration of the position of each grid cell at different times to obtain the three-dimensional distribution of the saturation degree of the activated carbon along with the time.
9. A computer device comprising a processor and a memory for storing a program executable by the processor, wherein the processor, when executing the program stored in the memory, implements the prediction method of any one of claims 1-7.
10. A storage medium storing a program which, when executed by a processor, implements the prediction method of any one of claims 1 to 7.

Description

Prediction method and system for competitive adsorption saturation of multiple pollutants on activated carbon Technical Field The invention relates to a prediction method and a prediction system for competitive adsorption saturation of multiple pollutants on active carbon, belonging to the field of waste gas treatment of environmental protection. Background Activated carbon adsorption is a common method for treating industrial waste gas, and is widely used in the industries of chemical industry, rubber, printing, coating and the like, and the waste gas in the industries generally contains multiple components. However, activated carbon gradually adsorbs and saturates during use, especially at different rates of saturation for different contaminants. When a certain position of the adsorption bed is saturated in advance or a certain pollutant is saturated preferentially, the waste gas can break through in advance, so that the treatment efficiency is reduced. It has been found that after a period of time, the removal rate of VOCs such as benzene, toluene, xylene, etc. is not less than 85% and the removal efficiency of CS 2, dimethyl disulfide, dimethyl sulfide, etc. is 0 or even negative. This may be due to the "roll-up" effect of competitive adsorption between the components. Competitive adsorption between various VOCs has been widely studied. For example Ouzzine et al studied the adsorption of mixtures of aldehydes, olefins and benzene on activated carbon, and found that aldehydes are most likely to saturate, while olefins are most likely to "roll out". The common management mode in the industry at present is regular replacement, empirical replacement or replacement after saturation detection, and the lack of saturation distribution prediction based on actual operation parameters causes two problems, namely (1) enterprises are difficult to reasonably arrange replacement/regeneration cycles according to actual loads, and cost waste is caused by too early replacement or excessive discharge is caused by too late replacement, and (2) supervision departments lack of quantifiable prediction tools, so that whether activated carbon is normally used under specified conditions is difficult to judge. Therefore, a prediction method for inputting the structure and operation parameters of the activated carbon device to generate the internal saturation distribution is needed, which can serve the operation and maintenance of enterprises and can be used as a supervision tool. The common method for detecting saturation mainly comprises measuring or calculating an iodine value, and the Chinese patent application with publication number of CN116499925A discloses a method for testing the adsorption saturation degree of active carbon. The method cannot judge the occurrence degree of the competitive adsorption of the activated carbon, namely, the method is applicable to single components and is not applicable to multi-component waste gas, and the method for calculating the saturation degree is also a method for predicting the adsorption capacity of the activated carbon on the volatile organic compounds according to single components, for example, the Chinese patent application with the publication number of CN112435717A, and the adsorption capacity of the VOCs on the activated carbon can be predicted by using the method according to the relation between the total rational characteristic influence factor of the VOCs, the total rational characteristic influence factor of the activated carbon and the total adsorption condition influence factor of the activated carbon and the predicted adsorption capacity of the activated carbon. At present, the prediction method for the saturation condition of the activated carbon mainly has two application defects that (1) aiming at single pollutant, the method does not accord with the actual condition of industrial application, and (2) the method only stays at the adsorption capacity of the predicted activated carbon, and the specific saturation condition at different positions in the activated carbon box body can not be predicted under the actual working condition. Therefore, there is a need to develop a method for predicting the saturation condition of the inside of the activated carbon adsorption tank under the actual use condition while considering various pollutants. Disclosure of Invention In view of the above, the invention provides a method, a system, a computer device and a storage medium for predicting competitive adsorption saturation of multiple pollutants on activated carbon, which can be oriented to activated carbon use enterprises and supervision departments to realize spatial distribution prediction and evaluation of the internal saturation condition of an activated carbon adsorption device. A first object of the present invention is to provide a method for predicting competitive adsorption saturation of multiple contaminants on activated carbon. A second object of the present invent