Method for predicting SO2 concentration at flue gas outlet of each layer of adsorption tower

Abstract

A method for predicting SO2 concentration at a flue gas outlet of each layer of an adsorption tower comprises the following steps: 1) drawing an activated carbon adsorption rate curve according to a change rule of the amount of SO2 adsorbed by activated carbon along with time in a desulfurization process; 2) establishing an activated carbon adsorption rate model according to the activated carbon adsorption rate curve; 3) dividing an activated carbon bed layer in the first-stage adsorption tower into multiple layers according to the flue gas trend, inputting a model constant, setting the SO2 concentration at a flue gas inlet of the first-stage adsorption tower and the blanking speed of each layer of activated carbon in the first-stage adsorption tower, and performing desulfurization process simulation on each layer of activated carbon; and 4) sequentially obtaining the SO2 concentration at each layer of flue gas outlet in the first-stage adsorption tower to realize prediction of the SO2 concentration at each layer of flue gas outlet in the first-stage adsorption tower. By constructing an activated carbon adsorption rate equation and combining actual engineering parameters, the SO2 concentration at each layer of flue gas outlet of the adsorption tower is obtained, and prediction of the SO2 concentration at each layer of flue gas outlet of the adsorption tower is realized.

Description

Technical Field

[0001] The present invention relates to a method for predicting the SO2 concentration at the flue gas outlet of an adsorption tower, and in particular to a method for predicting the SO2 concentration at the flue gas outlet of each layer of an adsorption tower, belonging to the technical field of activated carbon flue gas purification. Background Art

[0002] The activated carbon flue gas purification process has many advantages. At present, the two-stage flue gas purification process has been widely used in the field of sintering flue gas treatment, but there are also many problems. For example, the desulfurization of activated carbon mainly relies on micropores and surface functional groups, and the denitrification mainly relies on oxygen-containing functional groups on the surface of activated carbon. The dust is mainly composed of sintering original dust and carbon powder. Among them, the desulfurization, denitrification and dust removal capabilities are closely related to the activated carbon circulation volume. The larger the activated carbon circulation volume, the stronger the desulfurization and denitrification capabilities, but the dust removal capacity is weakened. For the currently common two-stage activated carbon process or activated carbon + SCR process, the activated carbon circulation volume is determined by the desulfurization capacity. When the SO2 concentration at the outlet of the desulfurization tower is less than 35mg / Nm 3 When the denitrification efficiency is not affected, it can reach about 80%.

[0003] The current control logic for activated carbon circulation is relatively crude. As described above, the circulation rate is adjusted by controlling the SO2 concentration at the flue gas outlet of the first tower. Firstly, because the activated carbon content in the system is as high as several thousand tons, its adsorption capacity for SO2 is very strong compared to other pollutants, resulting in significant hysteresis. For example, when the SO2 concentration at the outlet exceeds the standard, it means that the activated carbon circulation rate has been reduced for a long time, and it takes a long time for the system to return to optimal operation. Secondly, the activated carbon system is generally divided into three layers: front, middle, and back. The adsorption rate of SO2 in the flue gas varies significantly in different layers. For example, the front layer faces a high SO2 concentration in the flue gas, with a short residence time and a fast adsorption rate. The middle layer has a slower rate, and the back layer has the slowest rate. Thirdly, due to the large amount of activated carbon loaded in the adsorption tower and the lack of independent space between the front, middle, and back chambers, flue gas monitoring is not possible. Therefore, it is difficult to adjust the activated carbon residence time accordingly based on the flue gas concentration in the front, middle, and back chambers.

[0004] The following rules apply to the process of activated carbon running from top to bottom. Taking the front chamber as an example, the activated carbon at the top has a well-developed pore structure and rich surface functional groups, and has excellent desulfurization performance. The activated carbon in the middle has already adsorbed some SO2, the pores are blocked, and the rate of adsorption of SO2 slows down. The activated carbon at the bottom has already adsorbed a large amount of SO2, and its ability to adsorb SO2 in the gas again is the slowest. Therefore, the SO2 concentration at the front chamber outlet increases from top to bottom. Similarly, the same rules apply to the middle and rear chamber outlets. When the inlet flue gas volume and SO2 concentration are kept consistent, the pollutant concentration at the front chamber outlet is related to the feed rate of the front chamber activated carbon, the pollutant concentration at the middle chamber outlet is related to the feed rate of the front chamber and the feed rate of the middle chamber, and the pollutant concentration at the rear chamber outlet is related to the feed rate of the front chamber, the feed rate of the middle chamber, and the feed rate of the rear chamber. In theory, any change in the feed rate of each chamber will affect the change in the outlet SO2 concentration.

[0005] As mentioned above, the activated carbon circulation volume of the adsorption tower is related to the desulfurization, denitrification and dust removal capabilities. Adjusting the activated carbon circulation volume by simply detecting the change in SO2 concentration at the flue gas outlet of the activated carbon adsorption tower has obvious hysteresis. The activated carbon circulation volume is determined by the discharge rate of each chamber of the adsorption tower, and the discharge rate of each chamber is closely related to the SO2 concentration at the outlet of each chamber. Therefore, the corresponding activated carbon residence time can be adjusted according to the SO2 concentration in the flue gas at the outlet of each chamber of the adsorption tower to achieve precise control of the activated carbon circulation volume. At this time, in the absence of flue gas detection between the chambers, how to quickly determine the SO2 concentration at the flue gas outlet of each chamber of the activated carbon adsorption tower is obviously particularly important. Summary of the Invention

[0006] To address the shortcomings of the aforementioned prior art, the present invention proposes a method for predicting the SO2 concentration at the flue gas outlet of each layer of an adsorption tower. Based on the characteristic patterns of activated carbon desulfurization, this method establishes an activated carbon adsorption rate equation that relates the SO2 concentration at the flue gas outlet of each layer of the primary adsorption tower to the activated carbon feed rate of each layer. Combined with actual project parameters, the SO2 concentration at the flue gas outlet of each layer of the primary adsorption tower is calculated at different activated carbon feed rates. This method enables the prediction of the SO2 concentration at the flue gas outlet of each layer within the primary adsorption tower, enabling more precise control of the activated carbon circulation rate and guiding project operation.

[0007] According to an embodiment of the present invention, a method for predicting the SO2 concentration at the flue gas outlet of each layer of an adsorption tower is provided.

[0008] A method for predicting the SO2 concentration at the flue gas outlet of each layer of an adsorption tower, the method comprising the following steps:

[0009] 1) According to the change law of the amount of SO2 adsorbed by activated carbon over time during the desulfurization process, draw the activated carbon adsorption rate curve.

[0010] 2) Based on the activated carbon adsorption rate curve, establish an activated carbon adsorption rate model.

[0011] 3) The activated carbon bed in the primary adsorption tower is divided into multiple layers according to the direction of the flue gas. The model constants are input, the SO2 concentration at the flue gas inlet of the primary adsorption tower and the feeding rate of each layer of activated carbon in the primary adsorption tower are set, and the desulfurization process of each layer of activated carbon is simulated.

[0012] 4) The SO2 concentration at the flue gas outlet of each layer in the first-level adsorption tower is obtained in sequence, thereby realizing the prediction of the SO2 concentration at the flue gas outlet of each layer in the first-level adsorption tower.

[0013] In the present invention, in step 2), establishing the activated carbon adsorption rate model specifically includes the following sub-steps:

[0014] 201) According to the variation law of SO2 concentration ratio between the inlet and outlet of the flue gas of the first-stage adsorption tower over time, the rate of SO2 adsorption by activated carbon is divided into three stages: the first stage is a fast constant rate stage, the second stage is an exponential stage, and the third stage is a slow constant rate stage.

[0015] 202) Based on the activated carbon adsorption rate curve and the fact that the rate of activated carbon adsorption of SO2 is constant in the first and third stages, an activated carbon adsorption rate equation is constructed.

[0016] 203) The activated carbon bed in the primary adsorption tower is divided into grids, and the activated carbon adsorption rate equation is applied to each grid in turn according to the direction of the flue gas.

[0017] In the present invention, in sub-step 202), the activated carbon adsorption rate equation is:

[0018]

[0019] Where: Q is the adsorption capacity of activated carbon, mg / g. t is the residence time of activated carbon in the first-stage adsorption tower, h. α is the correction term. C is the SO2 concentration in the flue gas, mg / m 3 l is the reaction order of SO2 elementary reaction to produce sulfuric acid. Ea is the activation energy of activated carbon, kJ / mol. R is the gas constant, J / (mol·K). T is the flue gas temperature, K. K1 is the adsorption rate of SO2 in the first stage of sulfuric acid accumulation process in the activated carbon adsorption rate curve, h -1 K2 is the adsorption rate of SO2 in the third stage of sulfuric acid accumulation process in the activated carbon adsorption rate curve, h -1 Qs is the apparent saturated adsorption capacity of activated carbon for SO2, mg / g.

[0020] In the present invention, sub-step 203) specifically involves dividing the activated carbon bed within the primary adsorption tower into grids, with the height of the activated carbon bed divided into m grids and the width of the activated carbon bed divided into n grids. The activated carbon adsorption rate equation is applied to each grid in turn, and the adsorption capacity and SO2 concentration of each grid are iteratively calculated based on the activated carbon adsorption rate equation. The activated carbon adsorption capacity Q[0, j] of the topmost grid of the primary adsorption tower is Q[0, j] = 0, and the SO2 concentration C[i, 0] of the grid at the flue gas inlet of the primary adsorption tower is C0 = C0. That is,

[0021] Q[i,j]=Q[i-1,j]+dQ[i,j]...(2).

[0022] dt=(h / m) / v…(3).

[0023] C[i,j]=C[i,j-1]-dC[i,j]...(4).

[0024] Where: Q[i, j] represents the adsorption capacity of the grid corresponding to the i-th grid in the height direction and the j-th grid in the width direction of the activated carbon bed, dQ[i, j] represents the newly adsorbed capacity of the activated carbon in the current grid. C[i, j] represents the SO2 concentration of the grid corresponding to the i-th grid in the height direction and the j-th grid in the width direction of the activated carbon bed, and dC[i, j] represents the reduction in SO2 concentration due to adsorption by the activated carbon in the current grid. Where i ≤ m, j ≤ n. dt represents the residence time of the activated carbon in the current grid. h represents the height of the activated carbon bed in the primary adsorption tower. v represents the activated carbon feed rate at the corresponding position in the primary adsorption tower. C0 represents the SO2 concentration at the flue gas inlet of the primary adsorption tower.

[0025] In the present invention, in step 3), the activated carbon bed in the primary adsorption tower is divided into z layers according to the direction of the flue gas, namely the first activated carbon layer, the second activated carbon layer, ... the zth activated carbon layer, and the thickness of each activated carbon layer is L1, L2, ..., Lz, respectively. Where: L1 < L2 ≤ ... ≤ Lz, z ≥ 2.

[0026] In the present invention, according to the direction of the flue gas, the feeding speed of each layer of activated carbon in the first-level adsorption tower is V1, V2...V z Among them, V1>V2>……>V z .

[0027] In the present invention, in step 3), the desulfurization process is simulated for each layer of activated carbon, specifically:

[0028] The SO2 concentration C0 at the flue gas inlet of the first adsorption tower and the feed rate V1 of the first layer of activated carbon in the first adsorption tower are detected online. The SO2 concentration C0 and the activated carbon feed rate V1 are used as the initial conditions for the simulated desulfurization of the first layer of activated carbon. The SO2 concentration C1 at the flue gas outlet of the first layer of activated carbon is calculated using the activated carbon adsorption rate equation. The SO2 concentration C1 at the flue gas outlet of the first layer of activated carbon is the SO2 concentration at the flue gas inlet of the second layer of activated carbon. The feed rate V2 of the second layer of activated carbon is detected online. The SO2 concentration C1 and the activated carbon feed rate V2 are used as the initial conditions for the simulated desulfurization of the second layer of activated carbon. The SO2 concentration C2 at the flue gas outlet of the second layer of activated carbon is calculated using the activated carbon adsorption rate equation.

[0029] By analogy, the SO2 concentration C at the flue gas outlet of the x-1th layer of activated carbon is calculated. x-1 . Online detection of the feeding speed V of the xth layer of activated carbon x , with the SO2 concentration C x-1 and activated carbon feeding speed V x As the initial condition of the x-th layer of activated carbon simulated desulfurization, the SO2 concentration C at the flue gas outlet of the x-th layer of activated carbon is calculated by the activated carbon adsorption rate equation. x .

[0030] Where: x represents the xth layer of activated carbon in the corresponding first-stage adsorption tower. x≤z.

[0031] In the present invention, in step 4), the desulfurization process of the zth layer of activated carbon in the primary adsorption tower is simulated according to step 3), so as to calculate the SO2 concentration C at the flue gas outlet of the z-1th layer of activated carbon. z-1 and the feeding speed V of the zth layer of activated carbon detected online z As the initial condition of the zth layer of activated carbon simulated desulfurization, the SO2 concentration C at the flue gas outlet of the zth layer of activated carbon is calculated by the activated carbon adsorption rate equation. z , that is, the simulated SO2 concentration at the flue gas outlet of the first-stage adsorption tower is obtained, and the desulfurization capacity of the first-stage adsorption tower is predicted based on this.

[0032] In the present invention, the simulated SO2 concentration C at the flue gas outlet of the first-stage adsorption tower is calculated. z , to predict the desulfurization capacity of the first-stage adsorption tower, specifically:

[0033] If the simulated SO2 concentration C z <35mg / Nm 3 , which means that under the corresponding parameter conditions, the desulfurization capacity of the first-stage adsorption tower is relatively strong, and the system can be operated according to this parameter.

[0034] If the simulated SO2 concentration C z≥35mg / Nm 3 , indicating that under the corresponding parameter conditions, the desulfurization capacity of the first-stage adsorption tower is weak. At this time, the feeding rate of each layer of activated carbon in the first-stage adsorption tower is adjusted until the adjusted simulated SO2 concentration C z '<35mg / Nm 3 , the system operates according to the adjusted activated carbon feeding speed.

[0035] In the present invention, in step 3), the model constants include: the height and width of the activated carbon bed in the primary adsorption tower, and the thickness of each layer of activated carbon in the primary adsorption tower.

[0036] In the current common two-stage activated carbon process, the activated carbon circulation volume is mainly determined by the desulfurization capacity. When the SO2 concentration at the flue gas outlet of the first-stage adsorption tower is less than 35mg / Nm 3 When the denitrification efficiency of the secondary adsorption tower is not affected, it can reach about 80%. The activated carbon adsorption tower is generally divided into multiple layers (such as front, middle and rear chambers). The adsorption rate of SO2 in the flue gas by activated carbon in different layers is also quite different. For example, the SO2 concentration in the flue gas faced by the front layer of activated carbon is high, the residence time of the activated carbon is short, the adsorption rate is fast, the rate in the middle layer is slower, and the rear layer is the slowest. Moreover, due to the large amount of activated carbon loaded in the adsorption tower, there is no independent space between the front, middle and rear chambers, and there are no flue gas detection conditions. Therefore, the activated carbon circulation volume is often adjusted by detecting and controlling the SO2 concentration at the flue gas outlet of the first-level tower. It can be imagined that the current activated carbon circulation volume control logic is relatively extensive and has obvious lag.

[0037] Given that the activated carbon circulation volume is determined by the feeding rate of each chamber of the adsorption tower, and the feeding rate of each chamber is closely related to the SO2 concentration at the outlet of each chamber. Therefore, the activated carbon feeding rate can be adjusted by predicting the SO2 concentration at the flue gas outlet of each chamber of the adsorption tower, thereby achieving precise control of the activated carbon circulation volume. Based on this, the present invention proposes a method for predicting the SO2 concentration at the flue gas outlet of each layer of the adsorption tower. In the present invention, through experimental research methods, according to the characteristic law of activated carbon desulfurization, an activated carbon adsorption rate equation is established that shows the relationship between the SO2 concentration at the flue gas outlet of each layer of the first-level adsorption tower and the activated carbon feeding rate of each layer. In combination with the actual parameters of the project, the SO2 concentration at the flue gas outlet of each layer of the first-level adsorption tower at different activated carbon feeding rates is obtained, thereby achieving the prediction of the SO2 concentration at the flue gas outlet of each layer in the first-level adsorption tower, and then achieving precise control of the activated carbon circulation volume, avoiding the inaccuracy and lag in the existing activated carbon circulation volume control, and facilitating the guidance of the project operation.

[0038] The method for predicting the SO2 concentration at the flue gas outlet of each layer of the adsorption tower according to the present invention mainly comprises the following steps:

[0039] 1) According to the change law of the amount of SO2 adsorbed by activated carbon over time during the desulfurization process, draw the activated carbon adsorption rate curve.

[0040] Through experimental research, the amount of SO2 adsorbed by activated carbon changes with time in the form of a curve, that is, the rate curve of SO2 adsorption by activated carbon is obtained. Figure 4 As shown in the figure, in the initial stage, the SO2 concentration in the flue gas is high, the activated carbon has a well-developed pore structure, and the rate of SO2 adsorption by the activated carbon remains at a fast average value. At the end of the reaction, due to the adsorption effect of the activated carbon, the SO2 concentration in the flue gas decreases. After partially adsorbing SO2, the activated carbon's pores become clogged, and the adsorption rate slows down, basically maintaining a relatively slow average value. The activated carbon adsorption rate curve shows that the amount of SO2 adsorbed by the activated carbon gradually increases with the extension of adsorption time, and the adsorption amount increases more slowly after a long period of time.

[0041] 2) Based on the activated carbon adsorption rate curve, establish an activated carbon adsorption rate model.

[0042] 201) Figure 2 As shown in the figure, according to the change pattern of the SO2 concentration ratio of the flue gas inlet and outlet of the first-stage adsorption tower over time, the activated carbon desulfurization rate, that is, the rate of activated carbon adsorption of SO2, can be divided into three stages. The first stage is a fast constant rate stage, the second stage is an exponential stage, and the third stage is a relatively slow constant rate stage.

[0043] like Figure 3 As shown in the figure, according to the change pattern of SO2 concentration at the flue gas outlet of the first-level adsorption tower over time, it can be seen that as time goes by, the adsorption capacity of activated carbon for SO2 gradually tends to saturation, the SO2 concentration at the flue gas outlet gradually increases, and after a long time, the SO2 concentration at the flue gas outlet increases more slowly.

[0044] 202) Based on the activated carbon adsorption rate curve and the fact that the rate of activated carbon adsorption of SO2 is constant in the first and third stages, the activated carbon adsorption rate equation is constructed:

[0045]

[0046] In formula (1), Q is the adsorption capacity of activated carbon, mg / g. t is the residence time of activated carbon in the first-stage adsorption tower, h. α is the correction term. C is the SO2 concentration in the flue gas, mg / m 3 l is the reaction order of SO2 elementary reaction to produce sulfuric acid. Ea is the activation energy of activated carbon, kJ / mol. R is the gas constant, J / (mol·K). T is the flue gas temperature, K. K1 is the adsorption rate of SO2 in the first stage of sulfuric acid accumulation process in the activated carbon adsorption rate curve, h -1K2 is the adsorption rate of SO2 in the third stage of sulfuric acid accumulation process in the activated carbon adsorption rate curve, h -1 Qs is the apparent saturated adsorption capacity of activated carbon for SO2, mg / g.

[0047] When the SO2 concentration in the sintering flue gas is 200-1000ppm, the moisture content is 10-12%, and the oxygen content is 15-17%, the reaction order of SO2 is calculated to be l=0.8, the correction term α=0.22, and K1=7.2h -1 , K2=0.008h -1 .

[0048] 203) The activated carbon bed in the primary adsorption tower is divided into grids, and the activated carbon adsorption rate equation is applied to each grid in turn according to the direction of the flue gas.

[0049] The grid division described here can be understood as establishing a coordinate system on the activated carbon bed of the primary adsorption tower, dividing the height and width of the activated carbon bed in the primary adsorption tower into grids respectively, and then applying the activated carbon adsorption rate equation to each grid in turn according to the direction of the flue gas, so that the adsorption amount, SO2 concentration, etc. of each grid can be iteratively calculated by software or computer program based on the equation.

[0050] Specifically, the activated carbon bed in the primary adsorption tower is divided into grids, with the height of the activated carbon bed divided into m grids and the width of the activated carbon bed divided into n grids. The activated carbon adsorption rate equation is applied to each grid in turn, and the adsorption capacity and SO2 concentration of each grid are iteratively calculated based on the activated carbon adsorption rate equation. That is,

[0051] Q[i,j]=Q[i-1,j]+dQ[i,j]...(2).

[0052] dt=(h / m) / v…(3).

[0053] C[i,j]=C[i,j-1]-dC[i,j]...(4).

[0054] Given the activated carbon adsorption capacity Q[0, j] = 0 at the top grid of the first-stage adsorption tower, the adsorption capacity of the activated carbon in any grid and the newly adsorbed capacity in the current grid can be obtained by iteratively calculating each grid from top to bottom using formula (2). Given the SO2 concentration C[i, 0] = C0 at the flue gas inlet of the first-stage adsorption tower, the SO2 concentration at the outlet of any grid can be obtained by iteratively calculating each grid from the flue gas inlet to the flue gas outlet using formula (4).

[0055] In formulas (2)-(4), Q[i, j] represents the adsorption capacity of the grid corresponding to the i-th grid in the height direction and the j-th grid in the width direction of the activated carbon bed, and dQ[i, j] represents the newly added adsorption capacity of the activated carbon in the current grid. C[i, j] represents the SO2 concentration of the grid corresponding to the i-th grid in the height direction and the j-th grid in the width direction of the activated carbon bed, and dC[i, j] represents the reduced SO2 concentration under the adsorption of the activated carbon in the current grid. dC[i, j] can be converted from dQ[i, j]. Where i≤m, j≤n. dt represents the residence time of the activated carbon in the current grid. h is the height of the activated carbon bed in the first-stage adsorption tower. v is the activated carbon feed rate at the corresponding position in the first-stage adsorption tower. C0 is the SO2 concentration at the flue gas inlet of the first-stage adsorption tower.

[0056] When fitting the activated carbon adsorption rate equation (1) described above, the present invention divides the activated carbon bed in the primary adsorption tower into multiple grids, and iteratively calculates each grid in turn through software or a computer program. At this time, dQ can be understood as the newly added adsorption amount of the activated carbon in the current grid, and dt can be understood as the residence time of the activated carbon in the current grid. The division of the grids has completed the spatial positioning of different positions in the primary adsorption tower, and formula (3) shows that the residence time of the activated carbon in the corresponding grid is related to the discharge rate of the activated carbon at the corresponding position. Therefore, through the residence time of the activated carbon in the corresponding grid, the division of the grid, and the iterative calculation between the grids, the relationship between the various parameters in the above equation (1) and the structural data of the primary adsorption tower (including the height, width, total thickness, thickness of each layer, etc. of the adsorption tower) and the discharge rate of each layer of activated carbon is reflected.

[0057] For any grid in the activated carbon bed, as long as the inlet parameters such as SO2 concentration at the flue gas inlet of the first-stage adsorption tower, flue gas temperature, and the feeding speed of the first layer of activated carbon are given, the outlet parameters of the first grid can be calculated through the above-mentioned activated carbon adsorption rate equation (1). At the same time, the outlet parameters of the grid become the inlet parameters of the next grid. Then, by iterative calculations through software or computer programs, the outlet parameters of any grid can be obtained, so that the SO2 concentration at the flue gas outlet of each layer of activated carbon in the first-stage adsorption tower can be calculated, and the SO2 concentration at the flue gas outlet of each layer in the first-stage adsorption tower can be predicted to guide the operation of the project.

[0058] It should be noted that all formulas in the present invention are obtained by fitting by the inventors based on experiments and engineering applications, and all calculations are numerical values ​​converted according to prescribed units, and are obtained by substituting the converted numerical values ​​into the formulas (after converting the units, only the numerical values ​​are substituted into the formulas for calculation, without substituting the units, and the units are only used to adjust the size of the numerical values).

[0059] 3) The activated carbon bed in the primary adsorption tower is divided into multiple layers according to the direction of the flue gas. The model constants are input, the SO2 concentration at the flue gas inlet of the primary adsorption tower and the feeding rate of each layer of activated carbon in the primary adsorption tower are set, and the desulfurization process of each layer of activated carbon is simulated.

[0060] Generally speaking, adsorption towers are mostly divided into three chambers: front, middle and back. In this application, there is no limit on the number of layers of activated carbon bed in the adsorption tower, and it can be adjusted according to the scale of the adsorption tower, the actual requirements of flue gas purification and other specific conditions. In the scheme of this application, the activated carbon bed in the first-level adsorption tower is divided into z (z ≥ 2) layers according to the direction of flue gas, namely the first layer of activated carbon, the second layer of activated carbon...the zth layer of activated carbon, and the thickness of each layer of activated carbon is L1, L2...Lz, respectively, and the feeding speed of each layer of activated carbon is V1, V2...V z Taking into account the uniformity of the activated carbon feeding and the safety of operation in the entire adsorption tower, the thickness relationship between the activated carbon layers is L1<L2≤……≤Lz, and the relationship between the feeding speed of the activated carbon layers is V1>V2>……>V z .

[0061] The model constants described here include, for example, the height and width of the activated carbon bed within the primary adsorption tower, as well as the thickness of each layer of activated carbon within the primary adsorption tower. Subsequent desulfurization simulations and related parameter calculations for each layer of activated carbon are based on these input model constants.

[0062] The desulfurization process simulation for each layer of activated carbon is as follows:

[0063] The SO2 concentration C0 at the flue gas inlet of the first adsorption tower and the feed rate V1 of the first layer of activated carbon in the first adsorption tower are detected online. The SO2 concentration C0 and the activated carbon feed rate V1 are used as the initial conditions for the simulated desulfurization of the first layer of activated carbon. The SO2 concentration C1 at the flue gas outlet of the first layer of activated carbon is obtained by iterative calculation using software or a computer program based on the activated carbon adsorption rate equation. The SO2 concentration C1 at the flue gas outlet of the first layer of activated carbon is the SO2 concentration at the flue gas inlet of the second layer of activated carbon. The feed rate V2 of the second layer of activated carbon is detected online. The SO2 concentration C1 and the activated carbon feed rate V2 are used as the initial conditions for the simulated desulfurization of the second layer of activated carbon. The SO2 concentration C2 at the flue gas outlet of the second layer of activated carbon is obtained by iterative calculation using software or a computer program based on the activated carbon adsorption rate equation.

[0064] By analogy, the SO2 concentration C at the flue gas outlet of the x-1th layer of activated carbon is calculated. x-1 . Online detection of the feeding speed V of the xth layer of activated carbon x , with the SO2 concentration C x-1 and activated carbon feeding speed Vx As the initial condition of the x-th layer of activated carbon simulated desulfurization, the SO2 concentration C at the flue gas outlet of the x-th layer of activated carbon is obtained by iterative calculation based on the activated carbon adsorption rate equation through software or computer program. x .

[0065] Where: x represents the xth layer of activated carbon in the corresponding first-stage adsorption tower. x≤z.

[0066] In the above desulfurization simulation process, the relevant parameters detected online (including the SO2 concentration at the flue gas inlet of the first adsorption tower, the feeding speed of the first layer of activated carbon, the feeding speed of the second layer of activated carbon... the feeding speed of the xth layer of activated carbon V x The SO2 concentration at the flue gas outlet of each activated carbon layer under these actual engineering parameters is the average SO2 concentration at the corresponding location or area.

[0067] 4) According to the desulfurization process simulation of each layer of activated carbon in step 3), the SO2 concentration at the flue gas outlet of each layer in the primary adsorption tower is obtained in turn, thereby realizing the prediction of the SO2 concentration at the flue gas outlet of each layer in the primary adsorption tower.

[0068] After obtaining the predicted SO2 concentration at the flue gas outlet of each layer in the primary adsorption tower, the desulfurization capacity of the primary adsorption tower can be further predicted based on the predicted SO2 concentration at the flue gas outlet of the primary adsorption tower, specifically:

[0069] According to step 3), the desulfurization process of the zth layer of activated carbon in the primary adsorption tower is simulated to calculate the SO2 concentration C at the flue gas outlet of the z-1th layer of activated carbon. z-1 and the feeding speed V of the zth layer of activated carbon detected online z As the initial condition of the zth layer of activated carbon simulated desulfurization, the SO2 concentration C at the flue gas outlet of the zth layer of activated carbon is calculated by software or computer program according to the activated carbon adsorption rate equation. z , that is, the simulated SO2 concentration at the flue gas outlet of the first-stage adsorption tower is obtained, and the desulfurization capacity of the first-stage adsorption tower is predicted based on this.

[0070] If the simulated SO2 concentration C z <35mg / Nm 3 , which means that under the corresponding parameter conditions, the desulfurization capacity of the first-stage adsorption tower is relatively strong and will not affect the denitrification efficiency of the subsequent second-stage adsorption tower. The system can be operated according to this parameter.

[0071] If the simulated SO2 concentration C z ≥35mg / Nm3 , indicating that under the corresponding parameter conditions, the desulfurization capacity of the first-stage adsorption tower is weak, which may affect the denitrification efficiency of the subsequent second-stage adsorption tower; at this time, the feeding rate of each layer of activated carbon in the first-stage adsorption tower is adjusted until the adjusted simulated SO2 concentration C z '<35mg / Nm 3 The system will run according to the adjusted activated carbon feeding speed. Adjusting the activated carbon feeding speed will change the activated carbon circulation volume accordingly, thus achieving precise control of the activated carbon circulation volume.

[0072] Compared with the prior art, the present invention has the following beneficial technical effects:

[0073] 1. The present invention establishes an activated carbon adsorption rate equation based on the characteristic law of activated carbon desulfurization through experimental research, which is the relationship between the SO2 concentration at the flue gas outlet of each layer of the first-level adsorption tower and the activated carbon feeding rate of each layer. In combination with the actual engineering parameters, the SO2 concentration at the flue gas outlet of each layer of the first-level adsorption tower under different activated carbon feeding rates is obtained, thereby realizing the prediction of the SO2 concentration at the flue gas outlet of each layer in the first-level adsorption tower.

[0074] 2. The present invention obtains the SO2 concentration at the flue gas outlet of each layer of the first-level adsorption tower by constructing an activated carbon adsorption rate equation, and predicts the desulfurization capacity of the first-level adsorption tower based on the predicted SO2 concentration at the flue gas outlet of the first-level adsorption tower, thereby optimizing the discharge rate of activated carbon in each layer of the adsorption tower.

[0075] 3. The present invention predicts the SO2 concentration at the flue gas outlet of each layer of the first-level adsorption tower by constructing an activated carbon adsorption rate equation, thereby adjusting and optimizing the corresponding activated carbon feeding rate, and further realizing precise control of the activated carbon circulation amount, avoiding the inaccuracy and lag in the control of the existing activated carbon circulation amount, and facilitating the guidance of the project operation.

[0076] 4. The predicted value calculated by the activated carbon adsorption rate equation in the present invention has a small deviation from the actual value, that is, the activated carbon adsorption rate model constructed by the present invention has a high degree of fitting and a good fitting effect, and can truly realize the prediction of the SO2 concentration at the flue gas outlet of each layer of the adsorption tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Figure 1 This is a schematic diagram of a method for predicting the SO2 concentration at the flue gas outlet of each layer of an adsorption tower according to the present invention;

[0078] Figure 2 This is the change of SO2 concentration ratio at the inlet and outlet of the first-stage adsorption tower over time;

[0079] Figure 3 This is the graph showing the change of SO2 concentration at the flue gas outlet of the first-stage adsorption tower over time;

[0080] Figure 4 This is a graph showing the change in the amount of SO2 adsorbed by activated carbon over time. DETAILED DESCRIPTION

[0081] The technical solutions of the present invention are illustrated below with examples, and the scope of protection requested by the present invention includes but is not limited to the following embodiments.

[0082] Example 1

[0083] A method for predicting the SO2 concentration at the flue gas outlet of each layer of an adsorption tower, the method comprising the following steps:

[0084] 1) According to the change law of the amount of SO2 adsorbed by activated carbon over time during the desulfurization process, draw the activated carbon adsorption rate curve.

[0085] 2) Based on the activated carbon adsorption rate curve, establish an activated carbon adsorption rate model.

[0086] 3) The activated carbon bed in the primary adsorption tower is divided into multiple layers according to the direction of the flue gas. The model constants are input, the SO2 concentration at the flue gas inlet of the primary adsorption tower and the feeding rate of each layer of activated carbon in the primary adsorption tower are set, and the desulfurization process of each layer of activated carbon is simulated.

[0087] 4) The SO2 concentration at the flue gas outlet of each layer in the first-level adsorption tower is obtained in sequence, thereby realizing the prediction of the SO2 concentration at the flue gas outlet of each layer in the first-level adsorption tower.

[0088] Example 2

[0089] like Figure 1 As shown, a method for predicting the SO2 concentration at the flue gas outlet of each layer of the adsorption tower includes the following steps:

[0090] 1) If Figure 4 As shown in the figure, according to the change law of the amount of SO2 adsorbed by activated carbon over time during the desulfurization process, the activated carbon adsorption rate curve is drawn.

[0091] 2) Based on the activated carbon adsorption rate curve, establish an activated carbon adsorption rate model. This includes the following sub-steps:

[0092] 201) Figure 2 As shown in the figure, according to the change pattern of SO2 concentration ratio at the inlet and outlet of the flue gas of the first-stage adsorption tower over time, the rate of SO2 adsorption by activated carbon is divided into three stages: the first stage is a fast constant rate stage, the second stage is an exponential stage, and the third stage is a slow constant rate stage.

[0093] 202) Based on the activated carbon adsorption rate curve and the fact that the rate of activated carbon adsorption of SO2 is constant in the first and third stages, the activated carbon adsorption rate equation is constructed:

[0094]

[0095] Where: Q is the adsorption capacity of activated carbon, mg / g. t is the residence time of activated carbon in the first-stage adsorption tower, h. α is the correction term. C is the SO2 concentration in the flue gas, mg / m 3 l is the reaction order of SO2 elementary reaction to produce sulfuric acid. Ea is the activation energy of activated carbon, kJ / mol. R is the gas constant, J / (mol·K). T is the flue gas temperature, K. K1 is the adsorption rate of SO2 in the first stage of sulfuric acid accumulation process in the activated carbon adsorption rate curve, h -1 K2 is the adsorption rate of SO2 in the third stage of sulfuric acid accumulation process in the activated carbon adsorption rate curve, h -1 Qs is the apparent saturated adsorption capacity of activated carbon for SO2, mg / g.

[0096] 203) Divide the activated carbon bed in the first-stage adsorption tower into a grid. According to the direction of the flue gas, apply the activated carbon adsorption rate equation to each grid in turn. Specifically:

[0097] The activated carbon bed in the primary adsorption tower is divided into a grid, with the height of the activated carbon bed divided into m grids and the width of the activated carbon bed divided into n grids. The activated carbon adsorption rate equation is applied to each grid in turn, and the adsorption capacity and SO2 concentration of each grid are iteratively calculated based on the activated carbon adsorption rate equation. Here, the activated carbon adsorption capacity Q[0, j] of the top grid of the primary adsorption tower is Q[0, j] = 0, and the SO2 concentration C[i, 0] of the grid at the flue gas inlet of the primary adsorption tower is C0 = C0. That is,

[0098] Q[i,j]=Q[i-1,j]+dQ[i,j]...(2).

[0099] dt=(h / m) / v…(3).

[0100] C[i,j]=C[i,j-1]-dC[i,j]...(4).

[0101] Where: Q[i, j] represents the adsorption capacity of the grid corresponding to the i-th grid in the height direction and the j-th grid in the width direction of the activated carbon bed, dQ[i, j] represents the newly adsorbed capacity of the activated carbon in the current grid. C[i, j] represents the SO2 concentration of the grid corresponding to the i-th grid in the height direction and the j-th grid in the width direction of the activated carbon bed, and dC[i, j] represents the reduction in SO2 concentration due to adsorption by the activated carbon in the current grid. Where i ≤ m, j ≤ n. dt represents the residence time of the activated carbon in the current grid. h represents the height of the activated carbon bed in the primary adsorption tower. v represents the activated carbon feed rate at the corresponding position in the primary adsorption tower. C0 represents the SO2 concentration at the flue gas inlet of the primary adsorption tower.

[0102] 3) The activated carbon bed in the first-level adsorption tower is divided into z layers according to the direction of the flue gas, namely the first layer of activated carbon, the second layer of activated carbon...the zth layer of activated carbon. The thickness of each layer of activated carbon is L1, L2...Lz, and the feeding speed of each layer of activated carbon is V1, V2...V z Where: L1<L2≤……≤Lz, z≥2. V1>V2>……>V z .

[0103] Input model constants such as the width and height of the activated carbon bed in the first-stage adsorption tower, as well as the thickness of each layer of activated carbon in the first-stage adsorption tower, and simulate the desulfurization process for each layer of activated carbon. Specifically:

[0104] The SO2 concentration C0 at the flue gas inlet of the first adsorption tower and the feed rate V1 of the first layer of activated carbon in the first adsorption tower are detected online. The SO2 concentration C0 and the activated carbon feed rate V1 are used as the initial conditions for the simulated desulfurization of the first layer of activated carbon. The SO2 concentration C1 at the flue gas outlet of the first layer of activated carbon is calculated using the activated carbon adsorption rate equation. The SO2 concentration C1 at the flue gas outlet of the first layer of activated carbon is the SO2 concentration at the flue gas inlet of the second layer of activated carbon. The feed rate V2 of the second layer of activated carbon is detected online. The SO2 concentration C1 and the activated carbon feed rate V2 are used as the initial conditions for the simulated desulfurization of the second layer of activated carbon. The SO2 concentration C2 at the flue gas outlet of the second layer of activated carbon is calculated using the activated carbon adsorption rate equation.

[0105] By analogy, the SO2 concentration C at the flue gas outlet of the x-1th layer of activated carbon is calculated. x-1 . Online detection of the feeding speed V of the xth layer of activated carbon x , with the SO2 concentration C x-1 and activated carbon feeding speed V x As the initial condition of the x-th layer of activated carbon simulated desulfurization, the SO2 concentration C at the flue gas outlet of the x-th layer of activated carbon is calculated by the activated carbon adsorption rate equation. x .

[0106] Where: x represents the xth layer of activated carbon in the corresponding first-stage adsorption tower. x≤z.

[0107] 4) According to the desulfurization process simulation of each layer of activated carbon in step 3), the SO2 concentration at the flue gas outlet of each layer in the primary adsorption tower is obtained in turn, thereby realizing the prediction of the SO2 concentration at the flue gas outlet of each layer in the primary adsorption tower.

[0108] Example 3

[0109] Example 2 is repeated, except that in step 4), the desulfurization process of the zth layer of activated carbon in the primary adsorption tower is simulated according to step 3), so as to calculate the SO2 concentration C at the flue gas outlet of the z-1th layer of activated carbon. z-1 and the feeding speed V of the zth layer of activated carbon detected online z As the initial condition of the zth layer of activated carbon simulated desulfurization, the SO2 concentration C at the flue gas outlet of the zth layer of activated carbon is calculated by the activated carbon adsorption rate equation. z , that is, the simulated SO2 concentration at the flue gas outlet of the first-stage adsorption tower is obtained, and the desulfurization capacity of the first-stage adsorption tower is predicted based on this.

[0110] Example 4

[0111] Repeat Example 3, except that the simulated SO2 concentration C at the flue gas outlet of the first-stage adsorption tower is calculated. z , to predict the desulfurization capacity of the first-stage adsorption tower, specifically:

[0112] If the simulated SO2 concentration C z <35mg / Nm 3 , which means that under the corresponding parameter conditions, the desulfurization capacity of the first-stage adsorption tower is relatively strong, and the system can be operated according to this parameter.

[0113] If the simulated SO2 concentration C z ≥35mg / Nm 3 , indicating that under the corresponding parameter conditions, the desulfurization capacity of the first-stage adsorption tower is weak, which may affect the denitrification efficiency of the subsequent second-stage adsorption tower; at this time, the feeding rate of each layer of activated carbon in the first-stage adsorption tower is adjusted until the adjusted simulated SO2 concentration C z '<35mg / Nm 3 , the system operates according to the adjusted activated carbon feeding speed.

[0114] Application Example 1

[0115] The prediction method described in Example 2 was used to treat sintering flue gas from a steel smelter. In this method, the activated carbon adsorption rate equation is:

[0116]

[0117] The SO2 concentration in the sintering flue gas to be treated is 380ppm, the moisture content is 11%, and the oxygen content is 16%. Under these conditions, the reaction order of SO2 is calculated to be l=0.8, the correction term α=0.22, and K1=7.2h. -1 , K2=0.008h -1 .

[0118] Where: Q is the adsorption capacity of activated carbon, mg / g. t is the residence time of activated carbon in the primary adsorption tower, h. α is the correction term, α = 0.22. C is the SO2 concentration in the flue gas, C = 380ppm ≈ 1085.7mg / m 3 . l is the reaction order of the SO2 elementary reaction to produce sulfuric acid, l = 0.8. Ea is the activation energy of activated carbon, Ea = 0.89 kJ / mol. R is the gas constant, R = 8.314 J / (mol·K). T is the flue gas temperature, T = 413 K. K1 is the adsorption rate of SO2 in the first stage of sulfuric acid accumulation process in the activated carbon adsorption rate curve, K1 = 7.2 h -1 K2 is the adsorption rate of SO2 in the third stage of sulfuric acid accumulation process in the activated carbon adsorption rate curve, K2 = 0.008h -1 Qs is the apparent saturated adsorption capacity of activated carbon for SO2, Qs = 71 mg / g.

[0119] In this embodiment, the activated carbon bed in the primary adsorption tower has a width of W = 12m and a height of H = 29m. The activated carbon bed in the primary adsorption tower is divided into three layers according to the flue gas flow direction: a front chamber, a middle chamber, and a rear chamber. The thicknesses of each chamber are L1 = 0.26m, L2 = 0.82m, and L3 = 0.92m, respectively. The SO2 concentration at the flue gas inlet of the primary adsorption tower is measured online at C0 = 380ppm. The activated carbon feed rates for each chamber are V1 = 0.6m / h, V2 = 0.2m / h, and V3 = 0.1m / h, respectively.

[0120] Under the above parameter conditions, the desulfurization process of each layer of activated carbon is simulated, and the SO2 concentration at the flue gas outlet of each layer in the first-level adsorption tower is obtained in turn through software iterative calculation based on the activated carbon adsorption rate equation, thereby realizing the prediction of the SO2 concentration at the flue gas outlet of each layer in the first-level adsorption tower.

[0121] Application Example 2

[0122] Example 1 was repeated, except that in this example, the activated carbon feeding speeds of each chamber in the first-stage adsorption tower were V1 = 0.4 m / h, V2 = 0.13 m / h, and V3 = 0.08 m / h, respectively.

[0123] Under the above parameter conditions, the desulfurization process of each layer of activated carbon is simulated, and the SO2 concentration at the flue gas outlet of each layer in the first-level adsorption tower is obtained in turn through software iterative calculation based on the activated carbon adsorption rate equation, thereby realizing the prediction of the SO2 concentration at the flue gas outlet of each layer in the first-level adsorption tower.

[0124] Application Example 3

[0125] Example 1 was repeated, except that in this example, the activated carbon feeding speeds in each chamber in the first-stage adsorption tower were V1 = 0.2 m / h, V2 = 0.15 m / h, and V3 = 0.075 m / h, respectively.

[0126] Under the above parameter conditions, the desulfurization process of each layer of activated carbon is simulated, and the SO2 concentration at the flue gas outlet of each layer in the first-level adsorption tower is obtained in turn through software iterative calculation based on the activated carbon adsorption rate equation, thereby realizing the prediction of the SO2 concentration at the flue gas outlet of each layer in the first-level adsorption tower.

[0127] The predicted SO2 concentration at the flue gas outlet of each layer in the primary adsorption tower in Application Examples 1-3 was calculated by the activated carbon adsorption rate equation, and the actual SO2 concentration at the flue gas outlet of the primary adsorption tower in Application Examples 1-3 was detected by the SO2 concentration detection device. The results are as follows Table 1:

[0128] Table 1 Average SO2 concentration at the flue gas outlet of the front, middle and rear chambers of the adsorption tower under different conditions

[0129]

[0130] It can be seen from the data in Table 1 that the activated carbon adsorption rate equation constructed by the present invention, combined with actual engineering parameters, can obtain the SO2 concentration at the flue gas outlet of the front, middle and rear chambers of the first-level adsorption tower, and realize the prediction of the SO2 concentration at the flue gas outlet of each layer in the first-level adsorption tower.

[0131] Moreover, Table 1 shows that the predicted SO2 concentration at the flue gas outlet of the rear chamber in Application Example 1 is 8ppm, while the actual detected SO2 concentration is 7ppm; the predicted SO2 concentration at the flue gas outlet of the rear chamber in Application Example 2 is 14ppm, while the actual detected SO2 concentration is 15ppm; the predicted SO2 concentration at the flue gas outlet of the rear chamber in Application Example 3 is 28ppm, while the actual detected SO2 concentration is 32ppm. It can be seen that the deviation between the predicted value calculated by the activated carbon adsorption rate equation and the actual value is small, which also verifies that the activated carbon adsorption rate model constructed by the present invention has a high degree of fit and a good fitting effect, and can truly realize the prediction of the SO2 concentration at the flue gas outlet of each layer of the adsorption tower.

[0132] In Application Example 1, the predicted SO2 concentration at the flue gas outlet of the rear chamber of the first-stage adsorption tower is 8ppm≈22.9mg / m 3 , that is, the simulated SO2 concentration at the flue gas outlet of the first-stage adsorption tower is less than 35mg / Nm 3 , which shows that under the corresponding parameter conditions, the desulfurization capacity of the first-stage adsorption tower is relatively strong, and the system can be operated according to this parameter without affecting the denitrification efficiency of the subsequent second-stage adsorption tower.

[0133] In Application Example 2, the predicted SO2 concentration at the flue gas outlet of the rear chamber of the first-stage adsorption tower is 14ppm≈40mg / m 3 , that is, the simulated SO2 concentration at the flue gas outlet of the first-stage adsorption tower is greater than 35mg / Nm 3 , indicating that under the corresponding parameter conditions, the desulfurization capacity of the first-stage adsorption tower is weak, which may affect the denitrification efficiency of the subsequent second-stage adsorption tower; at this time, the feeding rate of each layer of activated carbon in the first-stage adsorption tower is adjusted until the adjusted simulated SO2 concentration is less than 35mg / Nm 3 , the system operates according to the adjusted activated carbon feeding speed.

[0134] In Application Example 3, the predicted SO2 concentration at the flue gas outlet of the rear chamber of the first-stage adsorption tower is 28ppm≈80mg / m 3 , that is, the simulated SO2 concentration at the flue gas outlet of the first-stage adsorption tower is greater than 35mg / Nm 3 , indicating that under the corresponding parameter conditions, the desulfurization capacity of the first-stage adsorption tower is weak, which may affect the denitrification efficiency of the subsequent second-stage adsorption tower; at this time, the feeding rate of each layer of activated carbon in the first-stage adsorption tower is adjusted until the adjusted simulated SO2 concentration is less than 35mg / Nm 3 , the system operates according to the adjusted activated carbon feeding speed.

Claims

1. A method for predicting the SO2 concentration at the flue gas outlet of each layer of an adsorption tower, the method comprising the following steps: 1) According to the variation of the amount of SO2 adsorbed by activated carbon over time during the desulfurization process, draw the activated carbon adsorption rate curve; 2) Establishing an activated carbon adsorption rate model based on the activated carbon adsorption rate curve; 3) The activated carbon bed in the primary adsorption tower is divided into multiple layers according to the direction of the flue gas, the model constants are input, the SO2 concentration at the flue gas inlet of the primary adsorption tower and the feeding rate of each layer of activated carbon in the primary adsorption tower are set, and the desulfurization process of each layer of activated carbon is simulated; 4) The SO2 concentration at the flue gas outlet of each layer in the primary adsorption tower is obtained in sequence, so as to realize the prediction of the SO2 concentration at the flue gas outlet of each layer in the primary adsorption tower.

2. The method according to claim 1, characterized in that: In step 2), the establishment of the activated carbon adsorption rate model specifically includes the following sub-steps: 201) According to the variation law of SO2 concentration ratio between flue gas inlet and outlet of the primary adsorption tower over time, the rate of SO2 adsorption by activated carbon is divided into three stages: the first stage is a fast constant rate stage, the second stage is an exponential stage, and the third stage is a slow constant rate stage; 202) Based on the activated carbon adsorption rate curve and the characteristic that the rate of activated carbon adsorption of SO2 is constant in the first and third stages, an activated carbon adsorption rate equation is constructed; 203) The activated carbon bed in the primary adsorption tower is divided into grids, and the activated carbon adsorption rate equation is applied to each grid in turn according to the direction of the flue gas.

3. The method according to claim 2, characterized in that: In sub-step 202), the activated carbon adsorption rate equation is: Where: Q is the adsorption capacity of activated carbon, mg / g; t is the residence time of activated carbon in the primary adsorption tower, h; α is the correction term; C is the SO2 concentration in the flue gas, mg / m 3 ; l is the reaction order of SO2 elementary reaction to produce sulfuric acid; Ea is the activation energy of activated carbon, kJ / mol; R is the gas constant, J / (mol·K); T is the flue gas temperature, K; K1 is the adsorption rate of SO2 in the first stage of sulfuric acid accumulation process in the activated carbon adsorption rate curve, h -1 ; K2 is the adsorption rate of SO2 in the third stage of sulfuric acid accumulation process in the activated carbon adsorption rate curve, h -1 ; Qs is the apparent saturated adsorption capacity of activated carbon for SO2, mg / g.

4. The method according to claim 3, characterized in that: Sub-step 203) is specifically as follows: the activated carbon bed in the primary adsorption tower is divided into grids, the height of the activated carbon bed is divided into m grids, the width of the activated carbon bed is divided into n grids, the activated carbon adsorption rate equation is applied to each grid in turn, and the adsorption amount and SO2 concentration of each grid are iteratively calculated according to the activated carbon adsorption rate equation; wherein, the activated carbon adsorption amount Q[0, j] of the topmost grid of the primary adsorption tower is Q[0, j]=0, and the SO2 concentration C[i, 0] of the grid at the flue gas inlet of the primary adsorption tower is C[i, 0]=C0; that is, Q[i,j]=Q[i-1,j]+dQ[i,j]...(2); dt=(h / m) / v…(3); C[i,j]=C[i,j-1]-dC[i,j]...(4); In the formula: Q[i, j] represents the adsorption amount of the grid corresponding to the i-th grid in the height direction of the activated carbon bed and the j-th grid in the width direction, dQ[i, j] represents the newly added adsorption amount of activated carbon in the current grid; C[i, j] represents the SO2 concentration of the grid corresponding to the i-th grid in the height direction of the activated carbon bed and the j-th grid in the width direction, dC[i, j] represents the reduced SO2 concentration under the adsorption of activated carbon in the current grid; where i≤m, j≤n; dt represents the residence time of activated carbon in the current grid; h is the height of the activated carbon bed in the first-level adsorption tower; v is the activated carbon feeding speed at the corresponding position in the first-level adsorption tower; C0 is the SO2 concentration at the flue gas inlet of the first-level adsorption tower.

5. The method according to any one of claims 1 to 4, characterized in that: In step 3), the activated carbon bed in the primary adsorption tower is divided into z layers according to the direction of the flue gas, namely the first layer of activated carbon, the second layer of activated carbon...the zth layer of activated carbon, and the corresponding thickness of each layer of activated carbon is L1, L2...Lz; wherein: L1<L2≤...≤Lz, z≥2.

6. The method according to claim 5, characterized in that: According to the direction of flue gas, the feeding speed of each layer of activated carbon in the primary adsorption tower is V1, V2...V z ; Among them, V1>V2>……>V z .

7. The method according to claim 5 or 6, characterized in that: In step 3), the desulfurization process is simulated for each layer of activated carbon, specifically: The SO2 concentration C0 at the flue gas inlet of the first-level adsorption tower and the feeding rate V1 of the first layer of activated carbon in the first-level adsorption tower are detected online, and the SO2 concentration C0 and the activated carbon feeding rate V1 are used as the initial conditions for the simulated desulfurization of the first layer of activated carbon, and the SO2 concentration C1 at the flue gas outlet of the first layer of activated carbon is calculated by the activated carbon adsorption rate equation; the SO2 concentration C1 at the flue gas outlet of the first layer of activated carbon is the SO2 concentration at the flue gas inlet of the second layer of activated carbon, and the feeding rate V2 of the second layer of activated carbon is detected online, and the SO2 concentration C1 and the activated carbon feeding rate V2 are used as the initial conditions for the simulated desulfurization of the second layer of activated carbon, and the SO2 concentration C2 at the flue gas outlet of the second layer of activated carbon is calculated by the activated carbon adsorption rate equation; By analogy, the SO2 concentration C at the flue gas outlet of the x-1th layer of activated carbon is calculated. x-1 ; Online detection of the feeding speed V of the xth layer of activated carbon x , with the SO2 concentration C x-1 and activated carbon feeding speed V x As the initial condition of the simulated desulfurization of the x-th layer of activated carbon, the SO2 concentration C at the flue gas outlet of the x-th layer of activated carbon is calculated by the activated carbon adsorption rate equation. x ; Wherein: x represents the xth layer of activated carbon in the corresponding first-stage adsorption tower; x≤z.

8. The method according to claim 7, characterized in that: In step 4), the desulfurization process of the zth layer of activated carbon in the primary adsorption tower is simulated according to step 3), so as to calculate the SO2 concentration C at the flue gas outlet of the z-1th layer of activated carbon. z-1 and the feeding speed V of the zth layer of activated carbon detected online z As the initial condition of the zth layer of activated carbon simulated desulfurization, the SO2 concentration C at the flue gas outlet of the zth layer of activated carbon is calculated by the activated carbon adsorption rate equation. z , that is, the simulated SO2 concentration at the flue gas outlet of the first-stage adsorption tower is obtained, and the desulfurization capacity of the first-stage adsorption tower is predicted thereby.

9. The method according to claim 8, characterized in that: According to the calculated simulated SO2 concentration C at the flue gas outlet of the first adsorption tower z , to predict the desulfurization capacity of the primary adsorption tower, specifically: If the simulated SO2 concentration C z <35mg / Nm 3 , indicating that under the corresponding parameter conditions, the desulfurization capacity of the primary adsorption tower is relatively strong, and the system can be operated according to this parameter; If the simulated SO2 concentration C z ≥35mg / Nm 3 , indicating that under the corresponding parameter conditions, the desulfurization capacity of the primary adsorption tower is weak. At this time, the feeding rate of each layer of activated carbon in the primary adsorption tower is adjusted until the adjusted simulated SO2 concentration C z '<35mg / Nm 3 , the system operates according to the adjusted activated carbon feeding speed.

10. The method according to any one of claims 1 to 9, characterized in that: In step 3), the model constants include: the width and height of the activated carbon bed in the primary adsorption tower, and the thickness of each layer of activated carbon in the primary adsorption tower.

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