Method for calculating porosity of activated carbon bed in activated carbon adsorption tower

Abstract

The invention belongs to the technical field of flue gas purification, and provides a method for calculating the porosity of an activated carbon bed in an activated carbon adsorption tower, which is used for calculating the porosity of the bed in real time by monitoring the pressure change and flue gas flow in the adsorption tower on line and combining physical characteristic parameters of activated carbon, establishing a mathematical model and ensuring the data accuracy and improving the operation efficiency of a system. According to the method, data can be collected in real time through a sensor, parameters are dynamically adjusted through a model algorithm, traditional sampling errors are effectively overcome, real-time and accurate monitoring is achieved, system stability is guaranteed, and implementation of an environmental protection target is assisted.

Description

Technical Field

[0001] This invention belongs to the field of flue gas purification technology, and relates to a method for purifying flue gas using a dry method, specifically a method for purifying flue gas using activated carbon and calculating the porosity of the activated carbon bed in an activated carbon adsorption tower. Background Technology

[0002] Activated carbon flue gas purification technology has the advantage of synergistic and efficient purification of multiple pollutants. It is suitable for the complex composition of sintering flue gas (containing SO2, NOx, dust, O2, water vapor, heavy metals, etc.) and large temperature fluctuations (110-250℃). It has been successfully applied to sintering flue gas purification systems.

[0003] The activated carbon flue gas purification system comprises multiple subsystems, including an adsorption system, a desorption system, and an acid production system. Flue gas is purified after passing through the activated carbon adsorption unit. Activated carbon particles circulate between the adsorption and desorption units, achieving a cycle of "adsorption of pollutants → heating and desorption activation (causing pollutants to escape) → cooling → adsorption of pollutants." The adsorption system is the key step in the adsorption of pollutants from sintering flue gas by activated carbon, while the desorption system is an important component for heating and regenerating the activated carbon after adsorption, ensuring the restoration of its activity. The formula for calculating the porosity of the activated carbon bed in the adsorption tower is: ε = (V 总 -V 固 ) / V 总 V 总 V represents the total volume of the bed. 固 This refers to the activated carbon particle size. By monitoring the ε value in real time, the flue gas flow rate and activated carbon particle size are dynamically adjusted to ensure maximum adsorption efficiency. Precise control of the ε value not only improves adsorption efficiency but also extends the service life of activated carbon and reduces operating costs.

[0004] Sintering flue gas contains a large amount of sintering ash. After electrostatic precipitator (ESP) treatment, a large amount of ultrafine dust enters the adsorption tower. The adsorption system contains a large amount of columnar activated carbon. Although the particle size distribution is uniform, during operation, the activated carbon will produce a small amount of small-sized activated carbon particles due to compression and collision, leading to the gradual accumulation of sintering ash and carbon powder in the adsorption tower. Under normal circumstances, this material will be discharged from the system after passing through the vibrating screen at the desorption tower, thus maintaining a uniform flow field within the tower. However, in actual operation, the ESP effect may deteriorate, and the quality of activated carbon and the effectiveness of equipment such as the vibrating screen may change, resulting in the accumulation of a large amount of ultrafine dust in the adsorption system, reducing bed porosity and increasing system resistance. To solve this problem, the accumulation of ultrafine dust can be effectively reduced, bed porosity can be stabilized, and efficient system operation can be ensured by optimizing the ESP equipment, regularly replacing with high-quality activated carbon, and improving the design of the vibrating screen.

[0005] Existing methods for calculating activated carbon bed porosity have significant shortcomings: they primarily rely on sampling activated carbon discharged from the bottom of the activated carbon adsorption tower, which results in large sampling variations and significant fluctuations in the calculated porosity, failing to accurately reflect the actual porosity within the bed. Furthermore, existing methods cannot achieve real-time monitoring of the activated carbon bed porosity within the adsorption tower. These problems severely impact the operational efficiency and stability of activated carbon flue gas purification systems, necessitating the development of a technical solution capable of accurately and in real-time calculating activated carbon bed porosity. Therefore, existing technologies urgently need improvement to address these issues. Summary of the Invention

[0006] To address the problem of real-time and accurate detection of activated carbon bed porosity in existing activated carbon adsorption towers, this invention proposes a method for calculating activated carbon bed porosity within the tower. By monitoring pressure changes and flue gas flow rate online within the tower, and combining this with activated carbon physical properties, a mathematical model is established to calculate bed porosity in real time, ensuring data accuracy and improving system operating efficiency. This method utilizes sensors to collect data in real time and dynamically adjusts parameters through model algorithms, effectively overcoming traditional sampling errors, achieving precise monitoring, ensuring system stability, and contributing to the achievement of environmental protection goals. Real-time monitoring not only allows for timely detection of changes in bed porosity but also optimizes activated carbon usage, reduces replacement frequency, and lowers operating costs. Simultaneously, accurate data supports system parameter adjustments, improving purification efficiency and ensuring emissions meet standards. Furthermore, this method provides real-time warnings of system anomalies, avoiding operational risks caused by abnormal porosity and enhancing overall operational safety. Real-time data feedback allows operators to respond quickly and adjust operating strategies, ensuring efficient operation of the adsorption tower.

[0007] According to the technical solution provided by the present invention, a method for calculating the porosity of the activated carbon bed in an activated carbon adsorption tower is provided.

[0008] A method for calculating the porosity of an activated carbon bed in an activated carbon adsorption tower, the method comprising the following steps:

[0009] S1. Detect the physicochemical properties of activated carbon;

[0010] S2. Activated carbon is loaded into the activated carbon adsorption tower, and the flue gas is transported to the flue gas inlet of the activated carbon adsorption tower. After being treated by the activated carbon adsorption tower, the flue gas is discharged from the exhaust port of the activated carbon adsorption tower.

[0011] S3. Detect the physicochemical properties of flue gas, the operating parameters of activated carbon in the activated carbon adsorption tower, and the operating parameters of flue gas in the activated carbon adsorption tower;

[0012] S4. Calculate the porosity of the activated carbon bed in the activated carbon adsorption tower based on the parameters detected in steps S1 and S3.

[0013] In this invention, the porosity of the activated carbon bed in the activated carbon adsorption tower is specifically calculated as follows:

[0014] △P=a·K·[(1-ε) 2 / ε 3 ]·(ρv 2 / 2g)·(L b / D p )...Formula I;

[0015] Where: K = 9 * (0.54 + 4.9 / Re) 0.5 ) 2 Re = ρvd / μ; ΔP = P 入 -P 出 d=L / L b ;

[0016] In the formula: ΔP is the pressure drop, Pa; K is the flue gas influence factor; ε is the porosity; ρ is the density of the flue gas, kg / m³ 3 v is the flow velocity of the flue gas entering the activated carbon adsorption tower, in m / s; g is the acceleration due to gravity, in m / s². 2 L b D represents the thickness of the activated carbon bed in the activated carbon adsorption tower, in meters (m). p ρ is the particle size of activated carbon in the activated carbon adsorption tower, in meters; Re is the Reynolds number; μ is the dynamic viscosity of the flue gas, in Pa·s; d is the characteristic length; P 入 P represents the pressure of the flue gas entering the activated carbon adsorption tower, in Pa. 出 The pressure of the flue gas discharged from the activated carbon adsorption tower is Pa; L is the height of the activated carbon bed inside the activated carbon adsorption tower, m; a is the adjustment coefficient, s. -2 The value ranges from 0.8 to 1.2.

[0017] In this invention, the physicochemical properties of activated carbon include the particle size of the activated carbon in the activated carbon adsorption tower.

[0018] In this invention, the physicochemical properties of the flue gas include its density.

[0019] In this invention, the operating parameters of activated carbon in the activated carbon adsorption tower include the thickness of the activated carbon bed and the height of the activated carbon bed in the activated carbon adsorption tower.

[0020] In this invention, the operating parameters of flue gas in the activated carbon adsorption tower include the flow rate of flue gas when it enters the activated carbon adsorption tower, the dynamic viscosity of flue gas, the pressure of flue gas when it enters the activated carbon adsorption tower, and the pressure of flue gas when it exits the activated carbon adsorption tower.

[0021] As a preferred method, the pressure of the flue gas entering the activated carbon adsorption tower is monitored in real time as P. 入The pressure of the flue gas discharged from the activated carbon adsorption tower in real time is used as P. 出 Substituting into Equation I, the real-time porosity ε of the activated carbon bed in the activated carbon adsorption tower is obtained. 实时 .

[0022] As a preferred option, the lower limit of the porosity of the activated carbon bed in the activated carbon adsorption tower is set to ε0. Comparison:

[0023] If ε 实时 If ≥ε0, continue running;

[0024] If ε 实时 If ε < 0, adjust the flue gas flow rate to the activated carbon adsorption tower or adjust the activated carbon to be transported to the activated carbon adsorption tower.

[0025] As a preferred option, if k·ε0≤ε 实时 <ε0, reduce the flue gas velocity delivered to the activated carbon adsorption tower;

[0026] If ε 实时 <k·ε0, adjust the amount of activated carbon delivered to the activated carbon adsorption tower (or the mass of activated carbon delivered to the activated carbon adsorption tower per unit time).

[0027] Wherein: k = 0.7-1.0, preferably k = 0.75-0.95, and even more preferably k = 0.8-0.9; for example: k takes values ​​of 0.7, 0.72, 0.75, 0.78, 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1.0.

[0028] In this invention, ε0 is 0.2-0.5, preferably 0.22-0.45, and more preferably 0.25-0.4; for example, ε0 takes the values ​​of 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, and 5.0.

[0029] In this invention, the particle size of the activated carbon in the activated carbon adsorption tower is less than 20 mm, preferably 1-15 mm, and more preferably 2-12 mm; for example, the particle size of the activated carbon packed in the activated carbon adsorption tower is 1-20 mm, 1.5-18 mm, 2-15 mm, 2.5-14 mm, 3-12 mm, 3-11 mm, 5-10 mm, 6-9 mm, or 7-8 mm. The particle size is the average particle size.

[0030] In this invention, the thickness of the activated carbon bed in the activated carbon adsorption tower is 1-5m, preferably 1.2-4m, and more preferably 1.4-3m. For example, the activated carbon bed thickness is 1.5m, 2m, 2.5m, 3m, 3.5m, or 4m.

[0031] In this invention, the height of the activated carbon bed in the activated carbon adsorption tower is 15-40m, preferably 18-35m, and more preferably 20-30m. For example, the activated carbon bed height is 22m, 25m, or 28m. During the adjustment process, the adsorption efficiency is monitored in real time to ensure that the pollutant removal rate is not less than 95%.

[0032] In existing technologies, activated carbon flue gas purification systems treat complex pollutants in sintering flue gas through adsorption and desorption processes. However, in actual operation, it is difficult to monitor the porosity of the activated carbon bed within the adsorption tower in real time. Existing methods rely on sampling and detection, which suffers from insufficient sample representativeness and inability to reflect dynamic changes, leading to increased system resistance and decreased purification efficiency. For example, when the electrostatic precipitator effect fluctuates or the quality of activated carbon changes, the decrease in bed porosity cannot be detected in time, affecting the stable operation of the system.

[0033] To address the aforementioned issues, the inventors discovered that existing porosity detection methods are limited by offline sampling and static calculations, making them unsuitable for dynamic operating conditions. By analyzing the relationship between activated carbon bed resistance and porosity, they proposed establishing a dynamic correlation between pressure drop and porosity by combining real-time operating parameters and a fluid dynamics model. Based on this, the inventors designed a method that detects multiple parameters and substitutes them into a formula to calculate porosity, achieving real-time monitoring and control.

[0034] Therefore, this application proposes a technical solution for detecting the physicochemical properties of activated carbon, which involves filling activated carbon into an adsorption tower and introducing flue gas, detecting the physicochemical properties and operating parameters of the flue gas, and calculating the porosity based on the detected parameters.

[0035] The process involves several key steps: First, detecting the physicochemical properties of activated carbon. This involves acquiring data on the activated carbon's intrinsic attributes, such as particle size and density, to provide foundational data for subsequent calculations. Second, loading activated carbon into the adsorption tower and introducing flue gas creates a suitable contact environment between the activated carbon and the flue gas. This can be achieved by controlling the packing thickness and adjusting the flue gas flow rate to ensure a complete adsorption reaction. Third, detecting the physicochemical properties and operating parameters of the flue gas involves real-time acquisition of dynamic data such as flue gas density, flow rate, and pressure difference. This can be achieved using devices such as pressure sensors and flow meters to provide input for model calculations. Fourth, calculating porosity based on the detected parameters involves dynamically solving a equation relating pressure drop and porosity. This can be achieved by establishing fluid dynamics equations and iteratively calculating to reflect the bed condition in real time.

[0036] Specifically, the particle size and density of activated carbon are first obtained through laboratory testing or online monitoring equipment. Then, the activated carbon is uniformly filled into the adsorption tower to form a bed of a specific thickness. After entering the adsorption tower through the inlet, the flue gas flows through the activated carbon bed to complete pollutant adsorption and is finally discharged from the outlet. During this process, parameters such as the pressure difference between the inlet and outlet, flue gas velocity, and viscosity are monitored in real time. These parameters, combined with the physicochemical data of the activated carbon, are used in formulas to calculate the porosity. For example, the porosity can be inferred using the pressure drop equation, and model errors can be corrected by adjusting coefficients to ensure that the calculation results accurately reflect actual operating conditions.

[0037] Compared to existing technologies, which rely on offline sampling to detect porosity, resulting in lag and sample bias, this solution directly calculates porosity by collecting operating parameters in real time, eliminating sampling errors. Furthermore, existing technologies cannot dynamically monitor changes in bed condition; this solution correlates porosity using a pressure drop model, allowing for continuous data updates during operation and providing a basis for system control.

[0038] Through the above technical solution, this application can obtain the porosity of the activated carbon bed in real time, accurately identify bed blockage or activated carbon deterioration problems, and adjust the flue gas flow rate or replace the activated carbon in a timely manner to maintain the efficient operation of the adsorption tower. This method avoids the limitations of sampling and detection, improves the stability of the purification system, extends the service life of activated carbon, and provides reliable technical support for the treatment of complex flue gas.

[0039] The flue gas inlet and outlet of the activated carbon flue gas adsorption tower have the same diameter. Flue gas is conveyed into the tower by a blower in the flue gas pipeline. Inside the tower, the flue gas comes into full contact with the activated carbon, and pollutants are effectively adsorbed. The purified flue gas is then discharged through the outlet. Due to the resistance of the activated carbon, the flue gas pressure differs between the inlet and outlet, with a higher pressure at the inlet and a lower pressure at the outlet, creating a pressure difference. This change is monitored in real time by a differential pressure sensor. Combined with flue gas velocity and viscosity data, the porosity calculation model is further optimized to ensure maximum adsorption efficiency. Simultaneously, the system automatically adjusts the blower power based on pressure difference changes to maintain a stable airflow and ensure the continuous and efficient operation of the adsorption tower.

[0040] The pressure drop ΔP refers to the pressure difference of the flue gas before and after passing through the activated carbon bed, which can be specifically detected in real time by a pressure sensor. 入 and export pressure P 出 The porosity ε, calculated subsequently, reflects changes in flow resistance within the bed. Porosity ε refers to the proportion of the void volume between activated carbon particles to the total bed volume; it can be indirectly measured by establishing a mathematical relationship between ε and pressure drop. The adjustment coefficient α corrects deviations between the model and actual operating conditions; its range is determined through fitting experimental data, and can be dynamically adjusted based on test results for different activated carbon types and flue gas compositions. The Reynolds number Re characterizes the flue gas flow state, calculated by combining flue gas velocity, viscosity, and characteristic length parameters, and reflects the impact of turbulence on pressure drop.

[0041] Specifically, by collecting real-time data on flue gas velocity, viscosity, density, activated carbon particle size, and bed thickness, combined with differential pressure measurement data, the system iteratively solves a pressure drop equation that includes porosity ε. This equation, by introducing a Reynolds number correction factor and an adjustment coefficient, can adapt to variations in particle size distribution and flue gas composition. For example, when activated carbon particle size decreases due to wear, the system automatically updates the Dp value and recalculates the porosity, thus eliminating measurement errors caused by material changes. During the iterative solution process, the system compares the calculated values ​​with the actual measured values ​​in real time, dynamically adjusting the model parameters to ensure the accuracy of porosity ε. Through continuous optimization, the model can adapt to fluctuations in operating conditions, further improving the operating efficiency of the adsorption tower, reducing maintenance costs, and providing a stable and reliable solution for industrial flue gas purification.

[0042] Compared to existing technologies, traditional methods rely on manual sampling to detect porosity, which cannot reflect the dynamic changes within the bed. This proposed solution, however, establishes a mathematical model of pressure drop and porosity, combined with real-time parameter acquisition, to achieve online continuous monitoring. Existing technologies do not consider the influence of flue gas properties and flow states on porosity calculations; this solution significantly improves calculation accuracy under complex operating conditions by introducing Reynolds number and adjustment coefficients.

[0043] Through the above technical solution, this application can accurately capture real-time changes in the porosity of the activated carbon bed, providing data support for optimizing flue gas velocity and activated carbon replenishment strategies. When the porosity is detected to be below the threshold, operating parameters can be adjusted in a timely manner to avoid abnormal increases in system resistance, thereby maintaining the stable operation of the adsorption tower and extending the service life of the activated carbon.

[0044] This application further specifies the physicochemical properties of activated carbon, including the particle size of activated carbon in the activated carbon adsorption tower; the physicochemical properties of flue gas, including the density of flue gas; the operating parameters of activated carbon in the activated carbon adsorption tower, including the thickness and height of the activated carbon bed in the activated carbon adsorption tower; and the operating parameters of flue gas in the activated carbon adsorption tower, including the flow rate of flue gas entering the activated carbon adsorption tower, the dynamic viscosity of flue gas, the pressure of flue gas entering the activated carbon adsorption tower, and the pressure of flue gas exiting the activated carbon adsorption tower.

[0045] The activated carbon particle size refers to the geometric dimensions (average particle size) of the activated carbon particles, which can be measured using a laser particle size analyzer or sieving method. This parameter directly affects the flow resistance and pore distribution within the bed. The flue gas density refers to the mass of flue gas per unit volume, which can be calculated using temperature and pressure sensors combined with the gas law. This parameter is used to correct the relationship between inertial and viscous forces during flow. The activated carbon bed thickness refers to the distance of the activated carbon-filled area along the flue gas flow direction, which can be obtained using a level gauge or measurement. This parameter is related to the flow path length and pressure drop calculation. The activated carbon bed height refers to the vertical space dimension formed by the activated carbon accumulation, which can be obtained by converting tower structure parameters and filling amount. This parameter is used to establish the relationship between characteristic length and flow state. The flue gas velocity refers to the average velocity of the flue gas passing through the bed cross-section, which can be calculated using a flow meter combined with the tower cross-sectional area. This parameter reflects the dynamic influence of flow kinetic energy on the pore structure. The flow dynamic viscosity refers to the internal friction force generated during flue gas flow, which can be determined by flue gas component analysis combined with a temperature compensation model. This parameter is used to correct the Reynolds number and flow state. The flue gas inlet pressure and outlet pressure refer to the gas pressure values ​​at both ends of the activated carbon adsorption tower. Specifically, they can be monitored in real time using a pressure transmitter. This pressure difference data is directly used in the core equation for porosity calculation.

[0046] Specifically, by simultaneously collecting data such as activated carbon particle size, flue gas density, bed thickness and height, flue gas velocity, viscosity, and inlet and outlet pressures, a complete parameter system required for porosity calculation is constructed. Activated carbon particle size determines the basic distribution of interparticle voids; flue gas density and viscosity jointly affect energy loss during flow; bed thickness and height relate to the geometric characteristics of the flow path; and flue gas velocity and pressure difference reflect the flow state under dynamic operating conditions. The coordinated detection of these parameters enables the porosity calculation equation to accurately characterize the structural changes of the activated carbon bed under actual operating conditions, avoiding calculation deviations caused by missing parameters or estimation errors.

[0047] Compared to existing technologies, current methods rely solely on activated carbon sampling to detect local porosity, neglecting the combined influence of flue gas properties and dynamic operating parameters on pore structure. This proposed solution integrates multi-dimensional detection of activated carbon properties, flue gas properties, and operating parameters, eliminating calculation errors caused by differences in sampling locations and fluctuations in operating conditions, thus achieving online real-time calculation of porosity.

[0048] This application further proposes to detect the pressure of flue gas entering the activated carbon adsorption tower in real time as P. 入 The pressure of the flue gas discharged from the activated carbon adsorption tower in real time is used as P. 出 Substituting into Equation I, the real-time porosity ε of the activated carbon bed in the activated carbon adsorption tower is obtained. 实时 .

[0049] Real-time detection refers to the continuous acquisition of pressure data of flue gas at the inlet and outlet of the activated carbon adsorption tower using pressure sensors. This can be achieved using embedded pressure transmitters or distributed pressure probes, thereby eliminating the lag inherent in traditional sampling and detection. Equation I refers to a mathematical model for calculating porosity based on parameters such as pressure drop, flow rate, activated carbon particle size, and bed thickness. Specifically, this can be achieved by applying the measured pressure data... 入 and P 出 Substituting into the pressure drop formula, we can deduce ε. 实时 This establishes a dynamic correlation. Real-time porosity ε 实时 This refers to the instantaneous value of the porosity of the activated carbon bed calculated based on the current operating parameters. Specifically, it can be achieved through the linkage between the data acquisition system and the calculation module, thereby reflecting the actual state inside the bed.

[0050] Specifically, during the operation of the activated carbon adsorption tower, inlet and outlet pressure data are simultaneously collected and transmitted to the computing unit. The pressure difference is then correlated with porosity using the pressure drop formula in Equation I. Since all parameters in Equation I, except ε, are known or measurable, the current porosity can be quickly calculated through iterative calculations or numerical methods. For example, when the system detects an abnormal pressure drop, it can immediately trigger a porosity update calculation and feed the results back to the control terminal, providing a basis for subsequent operational adjustments.

[0051] This application further proposes setting the lower limit of porosity of the activated carbon bed in the activated carbon adsorption tower as ε0, and comparing the real-time porosity ε0. 实时 The numerical relationship with ε0, if ε 实时 If ε ≥ 0, the system will maintain its operating state; if ε 实时 If ε < 0, the system operating parameters can be adjusted by changing the flue gas flow rate or replacing the activated carbon.

[0052] The lower porosity limit ε0 refers to the minimum critical porosity value required to maintain the normal adsorption function of the activated carbon bed. This value can be set through experimental testing or engineering experience, and can be, for example, within the range of 0.2-0.5. Its purpose is to provide a benchmark threshold for system operation. Real-time porosity ε 实时 This refers to real-time monitoring of the flue gas inlet pressure P. 入 With export pressure P 出 The dynamic porosity is calculated by substituting it into the pressure drop formula. Specifically, this can be achieved by using a pressure sensor and a data processing module together. Its function is to reflect the real-time changes in the degree of blockage inside the activated carbon bed.

[0053] Specifically, when the real-time porosity is detected to be lower than the set lower limit, it indicates that the flow channels inside the activated carbon bed may be blocked due to dust or carbon powder accumulation. In this case, reducing the flue gas velocity can reduce the risk of secondary blockage caused by particulate impact, while replacing the activated carbon can directly remove the degraded activated carbon particles. For example, when ε... 实时 When the flow rate is in the range of 0.7-1.0 times ε0, the flow rate should be adjusted first. 实时 When the concentration falls below 0.7 times ε0, the activated carbon needs to be replaced. This judgment logic achieves precise control through preset graded thresholds, avoiding the limitations of a single adjustment strategy.

[0054] This application further proposes that if the real-time porosity value is between the product of the adjustment coefficient and the lower limit of porosity and the lower limit of porosity, the flue gas velocity delivered to the activated carbon adsorption tower should be reduced; if the real-time porosity value is lower than the product of the adjustment coefficient and the lower limit of porosity, the activated carbon delivered to the activated carbon adsorption tower should be adjusted; the adjustment coefficient is taken as 0.7 to 1.0.

[0055] The adjustment coefficient is a parameter used to define the range between the real-time porosity value and the lower limit of porosity. It can be a pre-set fixed value or a variable dynamically adjusted according to the operating status of the activated carbon adsorption tower. The adjustment coefficient divides the real-time porosity value into different intervals, each corresponding to a different treatment measure. Adjusting the flue gas velocity delivered to the activated carbon adsorption tower involves reducing the volumetric flow rate of the flue gas by changing the valve opening or fan speed in the flue gas duct. This can be achieved by using an automatic control device to adjust the flow rate in real time. Reducing the flow rate decreases the fluid impact force on the activated carbon bed, thus slowing down the rate of porosity decrease. Adjusting the activated carbon delivered to the activated carbon adsorption tower involves replacing part or all of the activated carbon material to restore the bed structure. This can be achieved by periodically replenishing fresh activated carbon or using a circulation system that removes accumulated ash and carbon powder. Renewing the activated carbon material directly improves the bed porosity and maintains adsorption efficiency.

[0056] Specifically, during the operation of the activated carbon adsorption tower, pressure sensors collect real-time pressure difference data between the flue gas inlet and outlet. This data, combined with parameters such as flue gas density, flow rate, bed thickness, and activated carbon particle size, is used to iteratively calculate the real-time porosity using the pressure drop calculation formula. When the calculated real-time porosity value falls between the product of the adjustment coefficient and the lower porosity limit and the lower porosity limit itself, the control system automatically reduces the induced draft fan speed or closes the inlet valve opening to reduce the flue gas velocity to the set range. When the real-time porosity value further decreases below the product of the adjustment coefficient and the lower porosity limit, the material replacement program of the activated carbon conveying device is activated, discharging some of the accumulated ash and carbon powder from the system and replenishing an equal amount of fresh activated carbon. The adjustment coefficient is determined through experimental data optimization; for example, in the sintering flue gas treatment scenario, a coefficient range of 0.8 to 0.9 is selected to effectively distinguish between temporary porosity fluctuations and structural degradation.

[0057] This application further proposes that the lower limit of the porosity of the activated carbon bed in the activated carbon adsorption tower is set to 0.2-0.5, which can be 0.22-0.45, or further limited to 0.25-0.4.

[0058] The lower limit of porosity refers to the minimum allowable porosity value of the activated carbon bed during operation. This value can be determined through experimental testing or empirical data, such as setting it based on the pressure drop trend of the activated carbon adsorption tower. This lower limit is used to determine whether the porosity of the bed is too low due to dust or carbon powder accumulation, thus triggering an adjustment operation.

[0059] Specifically, when real-time monitoring shows that the porosity is below the lower limit, it indicates that blockage or uneven flow field distribution may occur inside the bed. In this case, it is necessary to reduce the flue gas velocity to decrease the amount of dust carried, or to add new activated carbon to restore the pore structure of the bed. The setting range of the lower limit of porosity needs to take into account both system resistance and purification efficiency. For example, an excessively high lower limit may increase the frequency of activated carbon replacement, while an excessively low lower limit may fail to provide timely warning of the risk of blockage.

[0060] In this invention, the thickness of the activated carbon bed refers to the width of a fixed layer (in the direction of flue gas flow) formed by the accumulation of activated carbon particles within the adsorption tower. This thickness can be specifically monitored in real-time using a level gauge or direct measurement, and is directly determined by the structure of the activated carbon adsorption tower. This parameter directly affects the resistance distribution and adsorption efficiency as flue gas passes through the bed. The selection of the thickness range must balance adsorption efficiency and system pressure drop; too thin a layer may lead to insufficient adsorption, while too thick a layer increases pressure drop and exacerbates dust accumulation.

[0061] In some specific implementations, the thickness of the activated carbon bed can be achieved by layered filling, for example, by setting a support grid at the bottom of the adsorption tower, distributing the activated carbon particles evenly by a vibration device, and dynamically adjusting the filling rate using online monitoring data.

[0062] In this invention, the height of the activated carbon bed within the activated carbon adsorption tower refers to the vertical extension distance of the activated carbon bed within the tower (perpendicular to the flue gas flow direction). This height can be determined by the internal structure of the tower or through direct measurement, and is directly determined by the structure of the activated carbon adsorption tower. A reasonable height range balances gas flow resistance and activated carbon adsorption efficiency, avoiding problems such as uneven airflow distribution due to excessively low height or excessive local pressure drop due to excessively high height. For example, in sintering flue gas treatment scenarios, an appropriate height range helps maintain a uniform distribution of activated carbon particles, reduces local accumulation of ultrafine dust, and thus improves the accuracy of porosity calculations.

[0063] The technical solution of this invention allows for precise calculation of the porosity of the activated carbon bed within the activated carbon adsorption tower, ensuring the tower's purification effect on flue gas and preventing blockage due to excessively low porosity. This, in turn, avoids the risk of overheating and ignition of the activated carbon bed caused by flue gas. Furthermore, by accurately calculating the porosity of the activated carbon bed within the tower, the invention prevents premature replacement of activated carbon even when the porosity meets adsorption requirements, thus saving operating costs, extending the activated carbon's lifespan, and ensuring stable and efficient system operation. Moreover, the precise calculation of the activated carbon bed's porosity allows for prediction of the tower's purification effect on flue gas, enabling advance adjustment of operating parameters, optimization of the adsorption process, effective reduction of operational risks, improved overall purification efficiency, and ensuring compliance with environmental emission standards. In addition, by monitoring porosity changes in real time and dynamically adjusting the activated carbon filling amount and replacement cycle, this invention further optimizes the adsorption tower's operation, ensuring high-efficiency purification even under complex operating conditions, reducing maintenance costs, and improving overall system reliability. Precise control of porosity can not only effectively avoid the risks of blockage and excessive temperature in activated carbon beds due to low porosity, but also ensure stable operation of the adsorption tower under complex conditions by optimizing the filling amount and replacement cycle, thereby reducing maintenance costs, improving the overall reliability of the system, and achieving environmental emission standards.

[0064] It should be noted that all formulas in this invention were obtained by the inventor based on experimental and engineering applications, and all calculations were obtained by substituting the converted values ​​into the formulas according to the prescribed units (after converting the units, only the values ​​are substituted into the formulas for calculation, not the units; the units are only used to adjust the magnitude of each parameter value to ensure the accuracy of the formulas).

[0065] Compared with the prior art, the technical solution proposed in this invention has the following beneficial technical effects:

[0066] 1. The porosity of the activated carbon bed in the adsorption tower directly affects the adsorption effect. This invention ensures efficient system operation, extends the service life of activated carbon, and improves overall purification efficiency by real-time monitoring and adjustment of porosity.

[0067] 2. By optimizing the mathematical model, the accuracy of porosity calculation is improved, the reliability of data is ensured, and a scientific basis is provided for system optimization.

[0068] 3. The technical solution of this invention realizes a real-time data feedback mechanism, enabling operators to quickly respond to changes in porosity, avoid system anomalies, reduce operational risks, and ensure equipment stability.

[0069] 4. The technical solution of this invention can accurately monitor and reduce the frequency of activated carbon replacement, reduce maintenance costs, improve economic benefits, and help achieve environmental protection goals. Attached Figure Description

[0070] Figure 1 The diagram shows the experimental results for deriving the technical principle of this invention. Detailed Implementation

[0071] The technical solution of the present invention will be illustrated below with examples. The scope of protection sought by the present invention includes, but is not limited to, the following embodiments.

[0072] The technical solutions in this application are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0073] Example 1

[0074] A method for calculating the porosity of an activated carbon bed in an activated carbon adsorption tower, the method comprising the following steps:

[0075] S1. Detect the physicochemical properties of activated carbon;

[0076] S2. Activated carbon is loaded into the activated carbon adsorption tower, and the flue gas is transported to the flue gas inlet of the activated carbon adsorption tower. After being treated by the activated carbon adsorption tower, the flue gas is discharged from the exhaust port of the activated carbon adsorption tower.

[0077] S3. Detect the physicochemical properties of flue gas, the operating parameters of activated carbon in the activated carbon adsorption tower, and the operating parameters of flue gas in the activated carbon adsorption tower;

[0078] S4. Calculate the porosity of the activated carbon bed in the activated carbon adsorption tower based on the parameters detected in steps S1 and S3.

[0079] Example 2

[0080] Repeat Example 1, except that the porosity of the activated carbon bed in the activated carbon adsorption tower is calculated as follows:

[0081] △P=a·K·[(1-ε) 2 / ε 3 ]·(ρv 2 / 2g)·(L b / D p )...Formula I;

[0082] Where: K = 9 * (0.54 + 4.9 / Re) 0.5 ) 2 Re = ρvd / μ; ΔP = P 入 -P 出 d=L / L b ;

[0083] In the formula: ΔP is the pressure drop, Pa; K is the flue gas influence factor; ε is the porosity; ρ is the density of the flue gas, kg / m³ 3 v is the flow velocity of the flue gas entering the activated carbon adsorption tower, in m / s; g is the acceleration due to gravity, in m / s². 2 L b D represents the thickness of the activated carbon bed in the activated carbon adsorption tower, in meters (m). p ρ is the particle size of activated carbon in the activated carbon adsorption tower, in meters; Re is the Reynolds number; μ is the dynamic viscosity of the flue gas, in Pa·s; d is the characteristic length; P 入 P represents the pressure of the flue gas entering the activated carbon adsorption tower, in Pa. 出 The pressure of the flue gas discharged from the activated carbon adsorption tower is Pa; L is the height of the activated carbon bed inside the activated carbon adsorption tower, m; a is the adjustment coefficient, s. -2 The value is 1.0.

[0084] Example 3

[0085] Example 2 is repeated, except that the physicochemical properties of the activated carbon include the particle size of the activated carbon in the activated carbon adsorption tower; the physicochemical properties of the flue gas include the density of the flue gas; the operating parameters of the activated carbon in the activated carbon adsorption tower include the thickness and height of the activated carbon bed in the activated carbon adsorption tower; and the operating parameters of the flue gas in the activated carbon adsorption tower include the flow rate of the flue gas when it enters the activated carbon adsorption tower, the dynamic viscosity of the flue gas, the pressure of the flue gas when it enters the activated carbon adsorption tower, and the pressure of the flue gas when it exits the activated carbon adsorption tower.

[0086] Example 4

[0087] Repeat Example 3, except that the pressure of the flue gas entering the activated carbon adsorption tower is monitored in real time as P. 入 The pressure of the flue gas discharged from the activated carbon adsorption tower in real time is used as P. 出 Substituting into Equation I, the real-time porosity ε of the activated carbon bed in the activated carbon adsorption tower is obtained. 实时 .

[0088] Example 5

[0089] Repeat Example 4, except that the lower limit of the porosity of the activated carbon bed in the activated carbon adsorption tower is set to 0.28, and compare:

[0090] If ε 实时 If the value is ≥0.28, continue running;

[0091] If ε 实时 If the value is less than 0.28, adjust the flue gas flow rate or the amount of activated carbon supplied to the activated carbon adsorption tower.

[0092] Example 6

[0093] Repeat Example 4, except that the lower limit of the porosity of the activated carbon bed in the activated carbon adsorption tower is set to 0.25, and compare:

[0094] If ε 实时 If the value is ≥0.25, continue running;

[0095] If ε 实时 If the value is less than 0.25, adjust the flue gas flow rate or the amount of activated carbon supplied to the activated carbon adsorption tower.

[0096] Example 7

[0097] Repeat Example 5, except that if 0.238 ≤ ε 实时 <0.28, reduce the flue gas velocity delivered to the activated carbon adsorption tower;

[0098] If ε 实时 <0.238, adjust the activated carbon supplied to the activated carbon adsorption tower.

[0099] Example 8

[0100] Repeat Example 5, except that if 0.26 ≤ ε 实时 <0.28, reduce the flue gas velocity delivered to the activated carbon adsorption tower;

[0101] If ε 实时 <0.26, adjust the activated carbon supplied to the activated carbon adsorption tower.

[0102] Example 9

[0103] Repeat Example 7, except that ε0 is 0.2.

[0104] Example 10

[0105] Repeat Example 7, except that ε0 is 0.29.

[0106] Application Examples

[0107] Experiments were conducted using activated carbon with the following particle sizes packed into an activated carbon adsorption tower:

[0108]

[0109] The operating data for flue gas and activated carbon in the activated carbon adsorption tower are as follows: the porosity of the fresh activated carbon bed is 0.3; the density of the flue gas is 0.9 kg / m³. 3 The flow velocity of the flue gas entering the activated carbon adsorption tower is 0.14 m / s; g is the acceleration due to gravity, 9.8 m / s². 2The thickness of the activated carbon bed in the activated carbon adsorption tower is 2m; the average particle size of the activated carbon in the activated carbon adsorption tower is 0.009m; the dynamic viscosity of the flue gas is 0.0000237 Pa·s; the height of the activated carbon bed in the activated carbon adsorption tower is 26.18m; the adjustment coefficient α is taken as 1.0 s. -2 .

[0110] Pressure sensors are installed at the flue gas inlet and outlet of the activated carbon adsorption tower. The pressure P is detected by the pressure sensor at the flue gas inlet of the activated carbon adsorption tower. 入 P is detected by an eye sensor at the flue gas outlet of the activated carbon adsorption tower. 出 .

[0111] The relationship between bed pressure drop and bed porosity after different operating times of the activated carbon adsorption tower was calculated using Formula I, as shown in the table below. Figure 1 As shown:

[0112]

[0113] According to this invention, ε0 is set to 0.28 and k to 0.85. The activated carbon operates normally under the current conditions for 1440 hours in the activated carbon adsorption tower. After 1440 hours, up to 2280 hours, the amount of flue gas delivered to the activated carbon adsorption tower is reduced, specifically: from 1440 to 2280 hours, the empty tower flow velocity of the flue gas is reduced to 0.13 m / s; from 2280 to 2340 hours, the flue gas volume is reduced to 0.11 m / s; and from 2340 to 2280 hours, the flue gas volume is reduced to 0.1 m / s. After 2280 hours, the activated carbon is replaced with fresh activated carbon.

[0114] The pressure drop at different times and the porosity of the activated carbon discharged from the activated carbon adsorption tower at the corresponding times were detected using GB / T7701.1-2008. The detected porosity is consistent with the calculated data in the table above, indicating that the porosity monitoring and adjustment mechanism proposed in this invention is effective, verifying the practicality and accuracy of the technology. The technical solution of this invention can ensure the long-term stable operation of the system. Further experiments show that this mechanism performs excellently under different operating conditions, significantly improving the utilization rate of activated carbon and the purification effect, providing reliable technical support for the environmental protection field. Through continuous optimization, this technology not only extends the service life of the equipment but also reduces energy consumption, achieving a win-win situation for both economic and environmental benefits. Experimental data shows that the technical solution of this invention can improve system operating efficiency by more than 30%, reduce maintenance costs by more than 20%, extend the activated carbon replacement cycle by 50%, reduce overall energy consumption by 15%, and completely prevent the occurrence of activated carbon ignition in the activated carbon adsorption tower.

Claims

1. A method for calculating the porosity of an activated carbon bed in an activated carbon adsorption tower, the method comprising the following steps: S1. Detect the physicochemical properties of activated carbon; S2. Activated carbon is loaded into the activated carbon adsorption tower, and the flue gas is transported to the flue gas inlet of the activated carbon adsorption tower. After being treated by the activated carbon adsorption tower, the flue gas is discharged from the exhaust port of the activated carbon adsorption tower. S3. Detect the physicochemical properties of flue gas, the operating parameters of activated carbon in the activated carbon adsorption tower, and the operating parameters of flue gas in the activated carbon adsorption tower; S4. Calculate the porosity of the activated carbon bed in the activated carbon adsorption tower based on the parameters detected in steps S1 and S3.

2. The method according to claim 1, characterized in that: The porosity of the activated carbon bed in the activated carbon adsorption tower is calculated as follows: △P = a·K·[(1 - ε) 2 / ε 3 ·(ρv 2 / 2g)·(L b / D p )……Equation I; Where: K = 9 * (0.54 + 4.9 / Re) 0.5 ) 2 Re = ρvd / μ; ΔP = P 入 -P 出 d=L / L b ; In the formula: ΔP is the pressure drop, Pa; K is the flue gas influence factor; ε is the porosity; ρ is the density of the flue gas, kg / m³ 3 v is the flow velocity of the flue gas entering the activated carbon adsorption tower, in m / s; g is the acceleration due to gravity, in m / s². 2 L b D represents the thickness of the activated carbon bed in the activated carbon adsorption tower, in meters (m). p ρ is the particle size of activated carbon in the activated carbon adsorption tower, in meters; Re is the Reynolds number; μ is the dynamic viscosity of the flue gas, in Pa·s; d is the characteristic length; P 入 P represents the pressure of the flue gas entering the activated carbon adsorption tower, in Pa. 出 The pressure of the flue gas discharged from the activated carbon adsorption tower is Pa; L is the height of the activated carbon bed inside the activated carbon adsorption tower, m; a is the adjustment coefficient, s. -2 The value ranges from 0.8 to 1.

2.

3. The method according to claim 1 or 2, characterized in that: The physicochemical properties of activated carbon include the particle size of the activated carbon in the activated carbon adsorption tower; The physical and chemical properties of flue gas include its density; The operating parameters of activated carbon in the activated carbon adsorption tower include the thickness and height of the activated carbon bed in the activated carbon adsorption tower. The operating parameters of flue gas in the activated carbon adsorption tower include the flow rate of flue gas when it enters the activated carbon adsorption tower, the dynamic viscosity of flue gas, the pressure of flue gas when it enters the activated carbon adsorption tower, and the pressure of flue gas when it exits the activated carbon adsorption tower.

4. The method according to claim 1 or 2, characterized in that: Real-time monitoring of the pressure of flue gas entering the activated carbon adsorption tower as P 入 The pressure of the flue gas discharged from the activated carbon adsorption tower in real time is used as P. 出 Substituting into Equation I, the real-time porosity ε of the activated carbon bed in the activated carbon adsorption tower is obtained. 实时 .

5. The method according to claim 4, characterized in that: Setting the lower limit of the porosity of the activated carbon bed in the activated carbon adsorption tower as ε0, compare: If ε 实时 If ≥ε0, continue running; If ε 实时 If ε < 0, adjust the flue gas flow rate to the activated carbon adsorption tower or adjust the activated carbon to be transported to the activated carbon adsorption tower.

6. The method according to claim 5, characterized in that: If k·ε0≤ε 实时 <ε0, reduce the flue gas velocity delivered to the activated carbon adsorption tower; If ε 实时 <k·ε0, adjust the amount of activated carbon supplied to the activated carbon adsorption tower; Wherein: k=0.7-1.0, preferably k=0.75-0.95, and even more preferably k=0.8-0.

9.

7. The method according to claim 4 or 5, characterized in that: ε0 is 0.2-0.5, preferably 0.22-0.45, and more preferably 0.25-0.

4.

8. The method according to any one of claims 1-7, characterized in that: The particle size of the activated carbon in the activated carbon adsorption tower is less than 20 mm, preferably 1-15 mm, and more preferably 2-12 mm.

9. The method according to any one of claims 1-7, characterized in that: The thickness of the activated carbon bed in the activated carbon adsorption tower is 1-5m, preferably 1.2-4m, and more preferably 1.4-3m.

10. The method according to any one of claims 1-7, characterized in that: The height of the activated carbon bed in the activated carbon adsorption tower is 15-40m, preferably 18-35m, and more preferably 20-30m.

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