Method for controlling simultaneous desulfurization and dechlorination of multi-pollutant flue gas carbon-based purification system

Abstract

The invention discloses a method for controlling simultaneous desulfurization and dechlorination of a multi-pollutant flue gas carbon-based purification system, which comprises the following steps of: systematically researching respective removal rules of SO2 and HCl by activated carbon and a competitive adsorption relation between the SO2 and the HCl, and establishing an adsorption capacity relation curve of the activated carbon to SO2 and HCl; according to the method, an SO2 removal equation of activated carbon and a competitive removal equation of SO2 and HCl are obtained through a relation curve, and on the basis of a carbon-based desulfurization, dechlorination and dust removal mechanism, on the premise that the desulfurization efficiency of the desulfurization tower is guaranteed, the desulfurization and dechlorination carbon circulation amount is further optimized, and meanwhile the operation cost is reduced. According to the method, the deviation between the predicted value obtained through calculation and the actual value is small, that is, the constructed SO2 removal equation and the constructed SO2 and HCl competitive removal equation are high in fitting degree and good in fitting effect, optimization of the carbon-based desulfurization and dechlorination circulation volume can be truly achieved, and guidance and protection are provided for operation of actual engineering.

Description

Technical Field

[0001] The invention relates to purification and treatment of multi-pollutant flue gas, and in particular to a method for controlling simultaneous desulfurization and dechlorination of a carbon-based flue gas purification system for multi-pollutant flue gas, and belongs to the technical field of activated carbon flue gas purification. Background Art

[0002] Activated carbon flue gas purification technology has the advantage of efficient purification of multiple pollutants, and is suitable for sintering flue gas with complex components (SO2, NO x , dust, O2, water vapor, heavy metals), and large temperature fluctuations (110-180℃). It has been successfully applied to the sintering flue gas purification system and has also been promoted to many industries such as coking and electric power. In the current ultra-low emission context, it has a large application space.

[0003] In the prior art, activated carbon flue gas purification technology can adopt a one-stage or two-stage adsorption mode. The two-stage adsorption flue gas purification process is as follows: Figure 1 As shown, the flue gas first passes through the primary tower and then the secondary tower. The activated carbon first goes to the secondary tower and then to the primary tower. It is then sent to the analysis tower for regeneration and then to the secondary tower for recycling. The activated carbon fills the adsorption tower from top to bottom. The upper part of the adsorption tower is connected to the tower feed bin, and the lower part is connected to the tower bottom hopper. The interior is a cavity structure. The activated carbon is discharged by a rotary valve or a long-axis roller discharge device. Under the action of gravity, the activated carbon is fed at a controlled rate by the rotary valve rotation speed or the long-axis roller discharge device frequency. During normal operation of the system, by adjusting the activated carbon feeding rate in the adsorption tower, the purpose of deep desulfurization, preliminary denitrification, and dust removal in the primary tower and deep denitrification in the secondary tower can be achieved, and ultimately the emission standards can be met. The desulfurization efficiency of the primary tower significantly affects the denitrification effect of the secondary tower. If the primary tower is thoroughly desulfurized, the flue gas entering the secondary tower is mainly NO. x At this time, ammonia is added at the inlet of the secondary tower, and an SCR reaction can occur on the surface of the activated carbon in the secondary tower.

[0004] Hydrogen chloride is the second most important gas in the steel industry after SO2 and NO x The fifth largest air pollutant is chlorine, dust and fluoride. Sintering is the main source of hydrogen chloride gas emissions in the steel industry. Chlorine in the sintering process mainly comes from ore, coal fuel and flux, and its emission concentration is mostly 20-60 mg / Nm 3 (In some cases it can reach 130mg / Nm 3The above) mainly depends on the total input of chlorine. Generally speaking, for the same ore, coal and flux, the concentration of chloride ions in coastal areas is higher than that in inland areas, because the concentration of chloride ions in precipitation in coastal areas is high; if the desulfurization wastewater (with a high concentration of chloride ions) is used for sprinkling water in the raw material field to suppress dust, the concentration of HCl in the sintering flue gas will also increase, which is easy to form a closed-loop circulation of chlorine, and will also lead to a substantial increase in the production of dioxins. When semi-dry desulfurization is used, the desulfurization ash generated contains calcium chloride, which will eventually affect the resource utilization efficiency of the desulfurization ash. At the same time, since hydrogen chloride is highly soluble in water and has a low acid dew point, it is easy to corrode downstream equipment. By studying the release law of hydrogen chloride in sintering flue gas, reducing the emission of hydrogen chloride from the source, and controlling the concentration of hydrogen chloride entering the downstream flue gas purification process, it is the key to ensure the safety of downstream processes and equipment operation. In addition, when solid waste is treated by incineration or pyrolysis, the flue gas generated also contains a large amount of chloride, which is also a major problem in the existing treatment of solid waste.

[0005] During the activated carbon adsorption process, SO2 is adsorbed first, followed by hydrogen chloride, and finally NO x In the current activated carbon two-stage adsorption process, the desulfurization tower preferentially adsorbs SO2 and less hydrogen chloride, which may lead to the presence of NO in the denitrification tower entrance. x And HCl gas, in order to achieve flue gas denitrification, NH3 needs to be added at the inlet of the denitrification tower. Hydrogen chloride will combine with ammonia to form ammonium chloride, which will block and corrode the inlet louvers and pipelines of the secondary adsorption tower, causing safety hazards in the system. Summary of the invention

[0006] In view of the problem in the prior art that the safe and stable operation of the system is affected by the unsatisfactory removal of HCl in the flue gas, the present invention provides a method for controlling the simultaneous desulfurization and dechlorination of a carbon-based flue gas purification system with multiple pollutants, by systematically studying the removal rules of SO2 and HCl by activated carbon and the competitive adsorption relationship between the two, an adsorption capacity relationship curve of activated carbon for SO2 and HCl is established, the distribution rules of SO2 and HCl in the activated carbon and the gas phase are calculated by the relationship curve, and then the conditions for the safe and stable operation of the system are judged, and the downward speed of the activated carbon is adjusted and controlled to ensure that SO2 and HCl are discharged in compliance with the standards and the safe and stable operation of the system is achieved.

[0007] In order to achieve the above technical objectives, the technical solutions adopted by the present invention are as follows:

[0008] A method for controlling the simultaneous desulfurization and dechlorination of a multi-pollutant flue gas carbon-based purification system, the method comprising the following steps:

[0009] 1) The original flue gas is treated by adsorption and purification in a carbon-based adsorption tower (including a carbon-based desulfurization tower and a carbon-based denitrification tower) and then reaches the emission standard. According to the adsorption rate curve of activated carbon to SO2 in the carbon-based desulfurization tower, the SO2 removal equation is constructed.

[0010] 2) Based on the competitive adsorption curve of activated carbon for SO2 and HCl in the carbon-based desulfurization tower, the competitive removal equation of SO2 and HCl was constructed.

[0011] 3) The theoretical feed rate of activated carbon is calculated based on the SO2 removal equation and the competitive removal equation of SO2 and HCl to obtain the content of SO2 and HCl at the flue gas outlet of the carbon-based desulfurization tower while meeting the working conditions. The actual feed rate of activated carbon in the carbon-based desulfurization tower is adjusted to be consistent with the calculated theoretical feed rate.

[0012] Preferably, in step 1), the removal equation of SO2 is constructed as follows:

[0013] 101) According to the variation pattern of SO2 concentration ratio between flue gas outlet and flue gas inlet of carbon-based desulfurization 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.

[0014] 102) According to the variation law of the adsorption amount of SO2 by activated carbon in the carbon-based desulfurization tower over time, the adsorption rate curve of activated carbon for SO2 is drawn.

[0015] 103) Based on the characteristic that the adsorption rate of SO2 by activated carbon is constant in the first and third stages and the adsorption rate curve of SO2 by activated carbon, the removal equation of SO2 by activated carbon in a carbon-based desulfurization tower is constructed.

[0016] Preferably, the removal equation of SO2 is:

[0017]

[0018] In formula (1): dQ / dt is the increment of the amount of SO2 adsorbed by activated carbon over time, mg / (g·h). Q is the amount of SO2 adsorbed by activated carbon, mg / g. t is the residence time of activated carbon in the carbon-based desulfurization tower, h. α is the correction term. C is the SO2 concentration in the original flue gas, mg / m 3 . l is the reaction order of the 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 original flue gas temperature, K. K1 is the adsorption rate of SO2 in the first stage of sulfuric acid accumulation process in the adsorption rate curve of activated carbon to SO2, h -1K2 is the adsorption rate of SO2 in the third stage of sulfuric acid accumulation process in the adsorption rate curve of activated carbon to SO2, h -1 Qs is the apparent saturated adsorption capacity of activated carbon for SO2, mg / g.

[0019] Preferably, in step 1), the competitive removal equation between SO2 and HCl is constructed as follows:

[0020] 201) According to the adsorption rate curve of activated carbon to SO2 in a carbon-based desulfurization tower, activated carbon adsorbing different amounts of SO2 is obtained.

[0021] 202) According to the variation law of the maximum adsorption amount of HCl by activated carbon that has adsorbed different amounts of SO2, the competitive adsorption curve of activated carbon for SO2 and HCl is drawn. Then, the competitive removal equation of SO2 and HCl is constructed based on the competitive adsorption curve of activated carbon for SO2 and HCl.

[0022] Preferably, the competitive removal equation of SO2 and HCl is:

[0023] Q h =-0.025+2.5 / (1+exp(Q-28.25) / 3.75 (2).

[0024] In formula (2): Q h is the adsorption capacity of activated carbon for HCl, mg / g. Q is the adsorption capacity of activated carbon for SO2, mg / g.

[0025] Preferably, in step 1), a flue gas inlet and a flue gas outlet are respectively opened on both side walls in the horizontal direction of the carbon-based desulfurization tower, and an activated carbon inlet and an activated carbon outlet are respectively opened on the top and the bottom in the vertical direction of the carbon-based desulfurization tower, and the contact mode between the original flue gas and the activated carbon in the carbon-based desulfurization tower is cross-flow contact.

[0026] Preferably, in step 1), according to the direction of the flue gas, the activated carbon bed in the carbon-based desulfurization tower is divided into a front unit bed, a middle unit bed, and a rear unit bed. The activated carbon feed rate of the front unit bed is set to V1, the activated carbon feed rate of the middle unit bed is set to V2, and the activated carbon feed rate of the rear unit bed is set to V3. Among them, V1:V2:V3=5.5~6.5:1.5~2.5:1, preferably 5.7~6.3:1.8~2.2:1.

[0027] Preferably, step 3) comprises:

[0028] 301) The activated carbon bed in the carbon-based desulfurization tower is divided into multiple sub-areas, and the SO2 adsorption amount of each sub-area is calculated according to the SO2 removal equation. The SO2 content at the flue gas outlet of the carbon-based desulfurization tower is obtained according to the SO2 adsorption amount of each sub-area. Finally, the feeding speed of the activated carbon in the carbon-based desulfurization tower is adjusted so that the SO2 content at the flue gas outlet of the carbon-based desulfurization tower meets the operating requirements.

[0029] 302) Based on step 301), the HCl adsorption amount of each sub-region is calculated according to the SO2 adsorption amount of each sub-region and the competitive removal equation of SO2 and HCl. Then, the HCl content at the flue gas outlet of the carbon-based desulfurization tower is obtained according to the HCl adsorption amount of each sub-region, and finally, the feeding speed of the activated carbon in the carbon-based desulfurization tower is adjusted so that the HCl content at the flue gas outlet of the carbon-based desulfurization tower meets the working condition requirements. Finally, the SO2 content and HCl content at the flue gas outlet of the carbon-based desulfurization tower both meet the working condition requirements.

[0030] Preferably, step 301) is specifically as follows: the height of the activated carbon bed is divided into m layers in the vertical direction, and the width of the activated carbon bed is divided into n columns in the horizontal direction, and then the entire activated carbon bed is divided into (m×n) sub-regions. The SO2 removal equation is applied to each sub-region in turn, and the SO2 adsorption amount and SO2 concentration of each sub-region are iteratively calculated according to the SO2 removal equation. Among them, the activated carbon adsorption amount Q[0, j] of the sub-region at the inlet of the activated carbon of the carbon-based desulfurization tower is 0, and the SO2 concentration C[i, 0] of the sub-region at the flue gas inlet of the carbon-based desulfurization tower is C0. Then:

[0031] Q[i,j]=Q[i-1,j]+dQ[i,j]...(3).

[0032] dt=(h / m) / v…(4).

[0033] C[i,j]=C[i,j-1]-dC[i,j]...(5).

[0034] Where: Q[i, j] represents the SO2 adsorption amount of the sub-region corresponding to the position of the i-th grid in the vertical height direction and the j-th grid in the horizontal width direction of the activated carbon bed, mg / g. dQ[i, j] represents the additional SO2 adsorption amount of activated carbon in the current sub-region, mg / g. C[i, j] represents the SO2 concentration of the sub-region corresponding to the position of the i-th grid in the vertical height direction and the j-th grid in the horizontal width direction of the activated carbon bed, mg / m 3 dC[i, j] represents the reduced SO2 concentration under the adsorption of activated carbon in the current sub-region, mg / m 3. Where i≤m, j≤n. dt represents the residence time of activated carbon in the current sub-area, h. h is the height of the activated carbon bed in the carbon-based desulfurization tower, m. v is the activated carbon feed rate of the corresponding sub-area in the carbon-based desulfurization tower, m / h. C0 is the SO2 concentration at the flue gas inlet of the carbon-based desulfurization tower, mg / m 3 .

[0035] Preferably, in step 301), the feeding speed of activated carbon in the carbon-based desulfurization tower is adjusted so that the SO2 content at the flue gas outlet of the carbon-based desulfurization tower meets the working condition requirements, specifically:

[0036] 301a) According to the SO2 concentration at the flue gas inlet of the carbon-based desulfurization tower, combined with the proportional relationship of the activated carbon feeding speed of the front unit bed layer, the middle unit bed layer, and the rear unit bed layer, and the SO2 concentration at the flue gas outlet of the carbon-based desulfurization tower is less than C 目 The theoretical feed rate of activated carbon in the front unit bed layer, the middle unit bed layer, and the rear unit bed layer is calculated by the SO2 removal equation as the target. After adjusting the actual feed rate of activated carbon in the front unit bed layer, the middle unit bed layer, and the rear unit bed layer to be consistent with the theoretical feed rate, step 302b) is performed.

[0037] 301b) Real-time detection of the real-time SO2 concentration at the flue gas outlet of the carbon-based desulfurization tower is recorded as C 实 Compare C 实 The target upper limit of SO2 concentration at the flue gas outlet of the carbon-based desulfurization tower is C 目 If C 实 <C 目 , record the activated carbon feeding rate of each unit bed layer, then slightly reduce the activated carbon feeding rate of each unit bed layer, then detect the adjusted real-time SO2 concentration, and continue to compare the adjusted real-time SO2 concentration with the target upper limit C of SO2 concentration. 目 Repeat this step until the real-time SO2 concentration C at the flue gas outlet of the carbon-based desulfurization tower is 实 ≥C 目 At this time, the last recorded C 实 <C 目 The carbon feeding rate of each unit bed layer at this time is the optimal feeding rate, thereby determining the optimal desulfurization circulation amount of activated carbon.

[0038] If the real-time SO2 concentration is C 实 ≥C 目 , slightly increase the activated carbon feeding rate of each unit bed layer, record the activated carbon feeding rate of each unit bed layer, then detect the adjusted real-time SO2 concentration, and continue to compare the adjusted real-time SO2 concentration with the target upper limit C of SO2 concentration. 目 Repeat this step until the real-time SO2 concentration C at the flue gas outlet of the carbon-based desulfurization tower is实 <C 目 At this time, the last recorded activated carbon feeding rate of each unit bed is the optimal feeding rate, thereby determining the optimal desulfurization cycle of activated carbon. 目 ≤35mg / Nm 3 .

[0039] Preferably, in step 302), the activated carbon feeding rate in the carbon-based desulfurization tower is adjusted so that the HCl content at the flue gas outlet of the carbon-based desulfurization tower meets the operating conditions. Specifically, when the activated carbon feeding rate of each unit bed in the carbon-based desulfurization tower is the operating condition of the optimal desulfurization cycle of the activated carbon, the current SO2 adsorption amount of each unit bed is calculated according to the activated carbon feeding rate of each unit bed and the SO2 removal equation at this time (it should be noted that the SO2 adsorption amount of each unit bed is calculated by applying the SO2 removal equation and the SO2 and HCl competitive removal equation to the sub-areas divided by the unit bed). Then, the current HCl adsorption amount of each unit bed is calculated according to the SO2 adsorption amount of each unit bed and the SO2 and HCl competitive removal equation. Then, the HCl concentration at the flue gas outlet of the current carbon-based desulfurization tower is calculated and recorded as C s Compare C s The target upper limit of HCl concentration is C 标 If C s <C 标 , then maintain the current working condition. s ≥C 标 , slightly increase the activated carbon feeding rate of each unit bed layer, record the activated carbon feeding rate of each unit bed layer, and then calculate the HCl concentration at the flue gas outlet of the carbon-based desulfurization tower after adjustment, and continue to compare the HCl concentration C at the flue gas outlet of the carbon-based desulfurization tower after adjustment s The target upper limit of HCl concentration is C 标 Repeat this step until the HCl concentration C at the flue gas outlet of the carbon-based desulfurization tower is s <C 标 At this time, the last recorded activated carbon feeding rate of each unit bed is the optimal feeding rate, thereby determining the optimal desulfurization and dechlorination cycle of activated carbon. 标 ≤4mg / Nm 3 .

[0040] During the activated carbon adsorption process, SO2 is adsorbed first, followed by hydrogen chloride, and finally NO x Therefore, in the current common two-stage activated carbon process, the desulfurization and dechlorination processes are mainly completed in the desulfurization tower, and the activated carbon circulation volume is mainly determined by the desulfurization capacity. When the SO2 concentration at the flue gas outlet of the first adsorption tower (i.e., the desulfurization tower) is less than 35 mg / Nm 3When the denitration efficiency of the secondary adsorption tower (i.e., denitration tower) is not affected, reaching about 80%. However, the existing activated carbon circulation control logic is relatively extensive. Due to the large amount of activated carbon loaded in the adsorption tower, there is no independent space between the front, middle, and rear unit beds, and there is no condition for online flue gas detection. Therefore, the activated carbon circulation is often adjusted by detecting and controlling the SO2 concentration at the flue gas outlet of the primary tower (i.e., desulfurization tower), and the hysteresis is obvious. According to laboratory research, the denitration efficiency is not closely related to the activated carbon circulation, so the activated carbon circulation can meet the requirements of desulfurization and dechlorination. In the present invention, by systematically studying the removal rules of SO2 and HCl in the desulfurization tower and the competitive adsorption relationship between the two, the adsorption capacity relationship curve of activated carbon for SO2 and HCl is established, and the distribution rules of SO2 and HCl in the activated carbon and the gas phase are calculated by the relationship curve, so as to judge the conditions for safe and stable operation of the system, and the downward speed of the activated carbon is adjusted to ensure that SO2 and HCl meet the emission standards and achieve the purpose of safe and stable operation of the system.

[0041] In the present invention, since the SO2 content in the flue gas is much greater than the HCl content, and the activated carbon will preferentially adsorb SO2, the control logic of the present invention is mainly divided into two steps. First, according to the adsorption rate curve of activated carbon to SO2 in the carbon-based desulfurization tower, the SO2 removal equation is constructed. Specifically, it includes:

[0042] 101) According to the variation of the SO2 concentration ratio between the flue gas outlet and the flue gas inlet of the carbon-based desulfurization tower over time (such as Figure 4 As shown in Figure 2, the rate of activated carbon adsorption of SO2 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. Figure 5 As shown in the figure, according to the variation pattern of SO2 concentration at the flue gas outlet of the carbon-based desulfurization tower over time, it can be seen that with the extension of time, 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 slowly.

[0043] 102) According to the change law of the amount of SO2 adsorbed by activated carbon in the carbon-based desulfurization tower over time, the adsorption rate curve of activated carbon to SO2 is drawn. Through experimental research, the change law of the amount of SO2 adsorbed by activated carbon over time is expressed in the form of a curve, that is, the rate curve of SO2 adsorption by activated carbon is obtained. Figure 6As shown in the figure, in the initial stage, the SO2 concentration in the flue gas is high, the pore structure of the activated carbon is well developed, and the rate of SO2 adsorption by the activated carbon is maintained at a fast average value. At the end of the reaction, due to the adsorption of the activated carbon, the SO2 concentration in the flue gas decreases. After the activated carbon adsorbs part of the SO2, the pores are blocked, and the adsorption rate slows down, basically maintaining a relatively slow average value. From the activated carbon adsorption rate curve, it can be seen that as the adsorption time increases, the amount of SO2 adsorbed by the activated carbon gradually increases, and the adsorption amount increases slowly after a long time.

[0044] 103) According to the characteristic that the rate of activated carbon adsorbing SO2 is constant in the first and third stages, combined with the adsorption rate curve of activated carbon for SO2, the removal equation of activated carbon for SO2 in the carbon-based desulfurization tower is constructed:

[0045]

[0046] In formula (1): dQ / dt is the increment of the amount of SO2 adsorbed by activated carbon over time, mg / (g·h). Q is the amount of SO2 adsorbed by activated carbon at the start time during the calculation period, mg / g. t is the residence time of activated carbon in the carbon-based desulfurization tower, h. α is the correction term. C is the SO2 concentration in the original flue gas, mg / m 3 . l is the reaction order of the 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 original flue gas temperature, K. K1 is the adsorption rate of SO2 in the first stage of sulfuric acid accumulation process in the adsorption rate curve of activated carbon to SO2, h -1 K2 is the adsorption rate of SO2 in the third stage of sulfuric acid accumulation process in the adsorption rate curve of activated carbon to SO2, h -1 Qs is the apparent saturated adsorption capacity of activated carbon for SO2, mg / g. Generally, when the SO2 concentration in 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 .

[0047] After obtaining the SO2 removal equation, the activated carbon bed in the carbon-based desulfurization tower can be divided into front unit bed, middle unit bed and rear unit bed according to the direction of the flue gas, and the model constants are input at the same time (including the thickness of the front unit bed, the middle unit bed and the rear unit bed of the desulfurization tower, the height and width of the activated carbon bed in the desulfurization tower, etc., and the subsequent desulfurization simulation and related parameter calculation of each layer of activated carbon are based on the input model constants) and the SO2 concentration at the flue gas inlet of the carbon-based desulfurization tower is set, and then the desulfurization process of the activated carbon in each unit bed is simulated; and then the activated carbon feeding rate of the front unit bed, the middle unit bed and the rear unit bed is obtained, which can make the SO2 concentration at the flue gas outlet of the desulfurization tower within the set range, thereby realizing the optimization of the activated carbon desulfurization cycle. It should be noted that, based on laboratory research and engineering practice experience, under the thickness, height, width and other structures of each layer of activated carbon bed in the existing carbon-based desulfurization tower, considering multiple factors such as the feeding uniformity and operation safety of each layer of activated carbon in the entire desulfurization tower, the activated carbon feeding rates of the front unit bed layer, the middle unit bed layer, and the rear unit bed layer satisfy a certain proportional relationship, for example, V1:V2:V3=5.5~6.5:1.5~2.5:1, preferably 5.7~6.3:1.8~2.2:1, specifically: V1:V2:V3=6:2:1.

[0048] In the present invention, the activated carbon bed in the desulfurization tower is divided into grids, and the sub-SO2 removal equation is applied to the sub-areas contained in each grid in turn according to the direction of the flue gas. It should be noted that the grid division can be understood as establishing a coordinate system on the activated carbon bed of the desulfurization tower, dividing the height and width of the activated carbon bed in the desulfurization tower into grids respectively, and then applying the SO2 removal equation to the sub-areas contained in each grid in turn according to the direction of the flue gas, so that the SO2 adsorption amount of the sub-areas contained in each grid and the SO2 concentration in the atmosphere can be obtained by iterative calculation through software or computer program according to the equation.

[0049] Furthermore, the height of the activated carbon bed in the carbon-based desulfurization tower is divided into m layers in the vertical direction, and the width of the activated carbon bed is divided into n columns in the horizontal direction, and then the entire activated carbon bed is divided into (m×n) sub-regions; the SO2 removal equation is applied to each sub-region in turn, and the SO2 adsorption amount and SO2 concentration of each sub-region are iteratively calculated according to the SO2 removal equation; wherein, the activated carbon adsorption amount Q[0, j] of the sub-region at the activated carbon inlet of the carbon-based desulfurization tower is 0, and the SO2 concentration C[i, 0] of the sub-region at the flue gas inlet of the carbon-based desulfurization tower is C0; then:

[0050] Q[i,j]=Q[i-1,j]+dQ[i,j]...(3);

[0051] dt=(h / m) / v…(4);

[0052] C[i,j]=C[i,j-1]-dC[i,j]...(5);

[0053] Where: Q[i, j] represents the SO2 adsorption capacity of the sub-region corresponding to the position of the i-th grid in the vertical height direction and the j-th grid in the horizontal width direction of the activated carbon bed, mg / g; dQ[i, j] represents the additional SO2 adsorption capacity of the activated carbon in the current sub-region, mg / g; C[i, j] represents the SO2 concentration of the sub-region corresponding to the position of the i-th grid in the vertical height direction and the j-th grid in the horizontal width direction of the activated carbon bed, mg / m 3 ; dC[i, j] represents the reduced SO2 concentration under the adsorption of activated carbon in the current sub-region, mg / m 3 ; Where i≤m, j≤n; dt represents the residence time of activated carbon in the current sub-area, h; h is the height of the activated carbon bed in the carbon-based desulfurization tower, m; v is the activated carbon feeding speed of the corresponding sub-area in the carbon-based desulfurization tower, m / h; C0 is the SO2 concentration at the flue gas inlet of the carbon-based desulfurization tower, mg / m 3 ;

[0054] It should be noted that, when the present invention performs fitting calculations through the above activated carbon adsorption rate equation (1), the activated carbon bed in the carbon-based desulfurization tower is divided into multiple grid-shaped sub-regions, and each sub-region is iteratively calculated in turn through software or computer programs. At this time, dQ can be understood as the newly added adsorption amount of activated carbon in the current sub-region, and dt can be understood as the residence time of activated carbon in the current sub-region. The division of the grid-shaped sub-regions has completed the spatial positioning of different positions in the desulfurization tower, and formula (4) shows that the residence time of activated carbon in the corresponding grid is related to the feeding speed of activated carbon at the corresponding position. Therefore, through the residence time of activated carbon in the corresponding sub-region, the division of the sub-region, and the iterative calculation between the sub-regions, the relationship between the parameters in the above equation (1) and the structural data of the desulfurization tower (including the height, width, total thickness, thickness of each layer, etc. of the desulfurization tower) and the feeding speed of each layer of activated carbon is reflected.

[0055] In the present invention, for any grid-shaped sub-region in the activated carbon bed, as long as the inlet parameters such as SO2 concentration at the flue gas inlet of the carbon-based desulfurization tower, flue gas temperature, and activated carbon feeding speed in the front chamber are given, the outlet parameters of the first grid-shaped sub-region can be calculated through the above-mentioned activated carbon adsorption rate equation (1). At the same time, the outlet parameters of the grid-shaped sub-region become the inlet parameters of the next grid-shaped sub-region. Then, by iterative calculations successively through software or computer programs, the outlet parameters of any grid-shaped sub-region can be obtained. In the present invention, the activated carbon feeding rate of the front, middle and rear unit beds is an unknown quantity and a parameter that needs to be obtained and optimized. At this time, based on the direction of the flue gas, when the upper limit of the SO2 concentration at the flue gas outlet of the desulfurization tower is known (i.e., the outlet parameter of the last grid-shaped sub-area), and based on experience, the ratio of the activated carbon feeding rate of the front, middle and rear unit beds is set, and the aforementioned calculation process for obtaining the outlet parameters of any grid-shaped sub-area is reversed to calculate the activated carbon feeding rate of each unit bed, thereby optimizing the activated carbon circulation amount and guiding the operation of the actual project.

[0056] In the present invention, according to research, the saturated adsorption capacity of activated carbon for HCl is only 2.6 mg / g, and the saturated adsorption capacity of activated carbon for SO2 reaches 70 mg / g, which is much higher than the adsorption performance for HCl. The adsorption of HCl by activated carbon mainly depends on the alkaline functional groups on the surface of activated carbon. By simulating the mixed gas of SO2 and HCl in industrial flue gas, the adsorption amount of activated carbon for SO2 and HCl was compared, and thermal regeneration analysis was performed. The results are shown in Table 1:

[0057] Table 1 Adsorption performance of activated carbon for SO2 and HCl

[0058] <![CDATA[SO2 adsorption capacity mg / g]]> 50 37.95 27.12 10.19 0 HCl adsorption mg / g 0.01 0.13 1.43 2.35 2.6

[0059] As can be seen from the table, the amount of SO2 adsorbed by activated carbon is negatively correlated with the amount of HCl adsorbed, that is, the more SO2 adsorbed by activated carbon, the less HCl adsorbed. For example, when the amount of SO2 adsorbed by activated carbon is 50 mg / g, the amount of HCl adsorbed is basically 0, and when the amount of SO2 adsorbed is 0, the amount of HCl adsorbed is 2.6 mg / g. By studying the adsorption mechanism of activated carbon for SO2 and HCl, the competitive adsorption curve of activated carbon for SO2 and HCl in the carbon-based desulfurization tower is drawn, and the competitive removal equation of SO2 and HCl is constructed based on the competitive adsorption curve of SO2 and HCl, which specifically includes:

[0060] 201) According to the adsorption rate curve of activated carbon to SO2 in a carbon-based desulfurization tower, activated carbon adsorbing different amounts of SO2 is obtained.

[0061] 202) According to the variation law of the maximum adsorption amount of HCl by activated carbon that has adsorbed different amounts of SO2, the competitive adsorption curve of activated carbon for SO2 and HCl is drawn; then, the competitive removal equation of SO2 and HCl is constructed based on the competitive adsorption curve of activated carbon for SO2 and HCl:

[0062] Q h =-0.025+2.5 / (1+exp(Q-28.25) / 3.75 (2).

[0063] In formula (2): Q h is the adsorption capacity of activated carbon for HCl, mg / g. Q is the adsorption capacity of activated carbon for SO2, mg / g.

[0064] like Figure 7 (As shown in the figure) In the initial stage, the content of SO2 adsorbed by activated carbon is low, and the adsorption amount of HCl by the activated carbon is relatively large. As the content of SO2 adsorbed in the activated carbon gradually increases, the adsorption amount of HCl will gradually decrease, and after a long time, the adsorption amount will increase slowly (the adsorption amount of HCl gradually tends to 0).

[0065] In the present invention, in the above-mentioned calculation process of simulated desulfurization, the relevant parameters detected online (such as SO2 concentration and HCl concentration at the flue gas inlet of the carbon-based desulfurization tower) are the actual engineering parameters. This application is based on the existing actual engineering parameters to simulate and experimentally study the desulfurization process of the desulfurization tower, so as to obtain the activated carbon feeding rate of each unit bed under different SO2 concentration conditions at the flue gas inlet of the desulfurization tower, and make the SO2 concentration at the flue gas outlet of the carbon-based desulfurization tower meet the control standard without affecting the denitrification efficiency of the subsequent denitrification tower, thereby realizing the control and optimization of the activated carbon circulation amount in the activated carbon flue gas purification process, and providing guidance for the operation of the actual project.

[0066] Furthermore, after obtaining the activated carbon feeding rate of each chamber with a certain degree of optimization with the goal of SO2 concentration at the flue gas outlet of the carbon-based desulfurization tower meeting the control standard, the present application can further achieve in-depth optimization of the activated carbon circulation amount by slightly fine-tuning the activated carbon feeding rate of the front, middle and rear unit beds of the carbon-based desulfurization tower. The specific adjustment steps are as follows:

[0067] 301a) According to the SO2 concentration at the flue gas inlet of the carbon-based desulfurization tower, combined with the proportional relationship of the activated carbon feeding speed of the front unit bed layer, the middle unit bed layer, and the rear unit bed layer, and the SO2 concentration at the flue gas outlet of the carbon-based desulfurization tower is less than C 目The theoretical feed rate of activated carbon in the front unit bed layer, the middle unit bed layer and the rear unit bed layer is calculated by the SO2 removal equation as the target; the actual feed rate of activated carbon in the front unit bed layer, the middle unit bed layer and the rear unit bed layer is adjusted to be consistent with the theoretical feed rate and then step 302b is performed.

[0068] 301b) Real-time detection of the real-time SO2 concentration at the flue gas outlet of the carbon-based desulfurization tower is recorded as C 实 ; Compare C 实 The target upper limit of SO2 concentration at the flue gas outlet of the carbon-based desulfurization tower is C 目 The size of C 实 <C 目 , record the activated carbon feeding rate of each unit bed layer, then slightly reduce the activated carbon feeding rate of each unit bed layer, then detect the adjusted real-time SO2 concentration, and continue to compare the adjusted real-time SO2 concentration with the target upper limit C of SO2 concentration. 目 Repeat this step until the real-time SO2 concentration C at the flue gas outlet of the carbon-based desulfurization tower is 实 ≥C 目 At this time, the last recorded C 实 <C 目 The carbon feeding rate of each unit bed layer at this time is the optimal feeding rate, thereby determining the optimal desulfurization circulation amount of activated carbon.

[0069] If the real-time SO2 concentration is C 实 ≥C 目 , slightly increase the activated carbon feeding rate of each unit bed layer, record the activated carbon feeding rate of each unit bed layer, then detect the adjusted real-time SO2 concentration, and continue to compare the adjusted real-time SO2 concentration with the target upper limit C of SO2 concentration. 目 Repeat this step until the real-time SO2 concentration C at the flue gas outlet of the carbon-based desulfurization tower is 实 <C 目 At this time, the last recorded activated carbon feeding rate of each unit bed is the optimal feeding rate, so as to determine the optimal desulfurization cycle of activated carbon; among them, C 目 ≤35mg / Nm 3 .

[0070] The activated carbon feeding rate of each unit bed calculated in the above step 301a) is the preliminary optimization result of the premise of ensuring the desulfurization efficiency of the carbon-based desulfurization tower. Generally speaking, under the condition that the total concentration of pollutants at the flue gas inlet of the carbon-based desulfurization tower is kept constant, the smaller the SO2 concentration at the flue gas outlet of the carbon-based desulfurization tower, the greater the required activated carbon circulation amount. Therefore, the activated carbon feeding rate of each unit bed calculated in the above steps 301a) and 301b) is the optimal activated carbon feeding rate obtained by minimizing the activated carbon feeding rate of the front, middle and rear unit beds as much as possible under the condition of ensuring the desulfurization efficiency of the carbon-based desulfurization tower, thereby obtaining the best activated carbon circulation amount.

[0071] In the present invention, under the working condition where the optimal desulfurization circulation amount of activated carbon in the carbon-based desulfurization tower is determined, the optimal desulfurization and dechlorination circulation amount of activated carbon that satisfies the working condition requirements is further determined based on the working condition, and the specific adjustment steps are as follows: under the working condition where the activated carbon feeding rate of each unit bed in the carbon-based desulfurization tower is the optimal desulfurization circulation amount of the activated carbon, the current SO2 adsorption amount of each unit bed is calculated according to the activated carbon feeding rate of each unit bed at this time and the SO2 removal equation; then, the current HCl adsorption amount of each unit bed is calculated according to the SO2 adsorption amount of each unit bed and the competitive removal equation of SO2 and HCl; and then the current HCl concentration at the flue gas outlet of the carbon-based desulfurization tower is calculated and recorded as C s ; Compare C s The target upper limit of HCl concentration is C 标 The size of C s <C 标 , then maintain the current working condition; if C s ≥C 标 , slightly increase the activated carbon feeding rate of each unit bed layer, record the activated carbon feeding rate of each unit bed layer, and then calculate the HCl concentration at the flue gas outlet of the carbon-based desulfurization tower after adjustment, and continue to compare the HCl concentration C at the flue gas outlet of the carbon-based desulfurization tower after adjustment s The target upper limit of HCl concentration is C 标 Repeat this step until the HCl concentration C at the flue gas outlet of the carbon-based desulfurization tower is s <C 标 At this time, the last recorded activated carbon feeding rate of each unit bed is the optimal feeding rate, so as to determine the optimal desulfurization and dechlorination cycle of activated carbon; among them, C 标 ≤4mg / Nm 3 .

[0072] In the present invention, the activated carbon feeding speed of the front, middle and rear unit beds of the initially optimized carbon-based desulfurization tower is finely adjusted (reduced or increased), and the fine adjustment refers to fine-tuning the activated carbon feeding speed of each unit bed currently calculated by a certain smaller amplitude. The adjustment amplitude is not limited and can be selected in combination with actual engineering needs. For example, under the condition that the activated carbon feeding speed of the front, middle and rear unit beds meets V1:V2:V3=6:2:1, the activated carbon feeding speed of the front, middle and rear unit beds is adjusted according to the amplitude of 0.018m / h, 0.006m / h and 0.003m / h respectively. By making this small adjustment to the activated carbon feeding speed of each unit bed that is initially optimized, the minimum activated carbon circulation amount that meets the desulfurization control standard can be obtained in this process, that is, while ensuring the desulfurization efficiency, the investment cost is reduced. In addition, when further adjusting the activated carbon feeding speed of each unit bed to meet the dechlorination demand while ensuring the desulfurization efficiency in the future, the same fine adjustment logic is also used to adjust upward (increase).

[0073] It should be noted that the activated carbon feed rate of the front, middle and rear unit beds of the desulfurization tower obtained in the preliminary optimization in step 301a) is based on the SO2 concentration at the flue gas outlet of the desulfurization tower being less than C 目 The target is calculated, but the present invention is based on the characteristic law of activated carbon desulfurization to simulate the desulfurization process of the desulfurization tower. Therefore, although it is the result calculated under this premise, the initial SO2 concentration C 实 ≥C 目 In addition, the subsequent adjustment of the dechlorination target is based on the premise that the desulfurization meets the target requirements, and only upward adjustments are made (increasing the activated carbon feeding rate), which is beneficial to desulfurization.

[0074] In the present invention, during the laboratory research process, for the SO2 removal equation and the competitive removal equation of SO2 and HCl constructed by the present invention, given actual engineering parameters, including the SO2 concentration and HCl concentration at the flue gas inlet of the desulfurization tower, and the activated carbon feeding rate of the front, middle and rear unit beds, the simulated value of the SO2 concentration at the flue gas outlet of the desulfurization tower calculated by the SO2 removal equation and the simulated value of the HCl concentration at the flue gas outlet of the desulfurization tower calculated by the competitive removal equation of SO2 and HCl, respectively, have small deviations from the actual value of the SO2 concentration at the flue gas outlet detected by the SO2 concentration detection device and the actual value of the HCl concentration at the flue gas outlet detected by the HCl concentration detection device. Therefore, it is also explained that 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 optimize the activated carbon circulation amount, provide guidance for the operation of actual projects, and escort.

[0075] It should be noted that all formulas in the present invention are obtained by fitting by the inventor based on experiments and engineering applications, and all calculations are numerical values ​​converted according to prescribed units, and are obtained by substituting the numerical values ​​after conversion into the formulas (after conversion of 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).

[0076] Compared with the prior art, the present invention has the following beneficial technical effects:

[0077] 1. The present invention establishes the SO2 removal equation and the competitive removal equation between SO2 and HCl based on the relationship between the SO2 concentration at the flue gas outlet of the front, middle and rear unit beds of the carbon-based desulfurization tower and the activated carbon feeding rate of each unit bed according to the characteristic law of activated carbon desulfurization through experimental research methods, and based on the desulfurization, dechlorination and dust removal mechanism of carbon-based activated carbon, and on the premise of ensuring the desulfurization efficiency of the desulfurization tower, obtains the activated carbon feeding rates of the front, middle and rear unit beds at different SO2 concentrations at the flue gas inlet of the desulfurization tower, thereby optimizing the activated carbon desulfurization circulation volume and guiding the operation of the project.

[0078] 2. The present invention constructs a SO2 removal equation, and obtains a preliminary optimized activated carbon feeding rate in each chamber with the goal of ensuring that the SO2 concentration at the flue gas outlet of the carbon-based desulfurization tower meets the control standard, thereby achieving preliminary optimization of the activated carbon desulfurization circulation amount. The present invention also makes small adjustments to the preliminary optimized activated carbon feeding rate in each chamber, and while ensuring the desulfurization efficiency of the desulfurization tower, reduces the activated carbon feeding rates of the front, middle and rear unit beds as much as possible to obtain the optimal activated carbon feeding rate, thereby obtaining the best activated carbon circulation amount. Further, through the competitive removal equation of SO2 and HCl, the activated desulfurization and dechlorination carbon circulation amount is further optimized, that is, the investment cost is reduced while ensuring the desulfurization and dechlorination efficiency.

[0079] 3. The deviations between the predicted values ​​calculated by the SO2 removal equation and the competitive removal equation of SO2 and HCl in the present invention and the actual values ​​are small, that is, the SO2 removal equation and the competitive removal equation of SO2 and HCl constructed in the present invention have high fitting degree and good fitting effect, and can truly optimize the activated carbon desulfurization and dechlorination circulation volume, provide guidance for the operation of actual projects, and safeguard them. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] Figure 1 The control principle diagram of the method of the present invention is shown in FIG.

[0081] Figure 2 The present invention is a flow chart for determining the optimal desulfurization circulation amount of activated carbon.

[0082] Figure 3 The present invention provides a flow chart for determining the optimal desulfurization and dechlorination circulation amount of activated carbon.

[0083] Figure 4 This is a graph showing the change of the SO2 concentration ratio between the flue gas outlet and the flue gas inlet of the carbon-based desulfurization tower of the present invention over time.

[0084] Figure 5 This is a graph showing the change of SO2 concentration over time at the flue gas outlet of the carbon-based desulfurization tower of the present invention.

[0085] Figure 6 This is a graph showing the variation of the amount of SO2 adsorbed by the activated carbon of the present invention over time.

[0086] Figure 7 It is an adsorption relationship curve diagram when the activated carbon of the present invention adsorbs SO2 and HCl simultaneously. DETAILED DESCRIPTION

[0087] The technical solution of the present invention is illustrated below by way of example, and the scope of protection requested by the present invention includes but is not limited to the following embodiments.

[0088] Example 1

[0089] A method for controlling the simultaneous desulfurization and dechlorination of a multi-pollutant flue gas carbon-based purification system, the method comprising the following steps:

[0090] 1) The original flue gas is purified by adsorption in a carbon-based adsorption tower and then discharged in compliance with the emission standards. According to the adsorption rate curve of activated carbon to SO2 in the carbon-based desulfurization tower, the SO2 removal equation is constructed.

[0091] 2) Based on the competitive adsorption curve of activated carbon for SO2 and HCl in the carbon-based desulfurization tower, the competitive removal equation of SO2 and HCl was constructed.

[0092] 3) The theoretical feed rate of activated carbon is calculated based on the SO2 removal equation and the competitive removal equation of SO2 and HCl to obtain the content of SO2 and HCl at the flue gas outlet of the carbon-based desulfurization tower while meeting the working conditions. The actual feed rate of activated carbon in the carbon-based desulfurization tower is adjusted to be consistent with the calculated theoretical feed rate.

[0093] Example 2

[0094] Example 1 was repeated, except that in step 1), the SO2 removal equation was constructed as follows:

[0095] 101) According to the variation pattern of SO2 concentration ratio between flue gas outlet and flue gas inlet of carbon-based desulfurization 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.

[0096] 102) According to the variation law of the adsorption amount of SO2 by activated carbon in the carbon-based desulfurization tower over time, the adsorption rate curve of activated carbon for SO2 is drawn.

[0097] 103) Based on the characteristic that the adsorption rate of SO2 by activated carbon is constant in the first and third stages and the adsorption rate curve of SO2 by activated carbon, the removal equation of SO2 by activated carbon in a carbon-based desulfurization tower is constructed.

[0098] The removal equation of SO2 is:

[0099]

[0100] In formula (1): dQ / dt is the increment of the amount of SO2 adsorbed by activated carbon over time, mg / (g·h). Q is the amount of SO2 adsorbed by activated carbon, mg / g. t is the residence time of activated carbon in the carbon-based desulfurization tower, h. α is the correction term. C is the SO2 concentration in the original flue gas, mg / m 3 . l is the reaction order of the 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 original flue gas temperature, K. K1 is the adsorption rate of SO2 in the first stage of sulfuric acid accumulation process in the adsorption rate curve of activated carbon to SO2, h -1 K2 is the adsorption rate of SO2 in the third stage of sulfuric acid accumulation process in the adsorption rate curve of activated carbon to SO2, h -1 Qs is the apparent saturated adsorption capacity of activated carbon for SO2, mg / g.

[0101] Example 3

[0102] Example 2 was repeated, except that in step 1), the competitive removal equation between SO2 and HCl was constructed as follows:

[0103] 201) According to the adsorption rate curve of activated carbon to SO2 in a carbon-based desulfurization tower, activated carbon adsorbing different amounts of SO2 is obtained.

[0104] 202) According to the variation law of the maximum adsorption amount of HCl by activated carbon that has adsorbed different amounts of SO2, the competitive adsorption curve of activated carbon for SO2 and HCl is drawn. Then, the competitive removal equation of SO2 and HCl is constructed based on the competitive adsorption curve of activated carbon for SO2 and HCl.

[0105] The competitive removal equation of SO2 and HCl is:

[0106] Q h =-0.025+2.5 / (1+exp(Q-28.25) / 3.75) (2).

[0107] In formula (2): Q h is the adsorption capacity of activated carbon for HCl, mg / g. Q is the adsorption capacity of activated carbon for SO2, mg / g.

[0108] Example 4

[0109] Example 3 is repeated, except that in step 1), a flue gas inlet and a flue gas outlet are respectively opened on both side walls in the horizontal direction of the carbon-based desulfurization tower, and an activated carbon inlet and an activated carbon outlet are respectively opened on the top and the bottom in the vertical direction of the carbon-based desulfurization tower, and the contact mode between the original flue gas and the activated carbon in the carbon-based desulfurization tower is cross-flow contact.

[0110] Example 5

[0111] Example 4 was repeated, except that in step 1), the activated carbon bed in the carbon-based desulfurization tower was divided into a front unit bed, a middle unit bed, and a rear unit bed according to the direction of the flue gas. The activated carbon feed rate of the front unit bed was set to V1, the activated carbon feed rate of the middle unit bed was set to V2, and the activated carbon feed rate of the rear unit bed was set to V3. Among them, V1:V2:V3=5.5~6.5:1.5~2.5:1.

[0112] Example 6

[0113] Repeat Example 5, except that step 3) includes:

[0114] 301) The activated carbon bed in the carbon-based desulfurization tower is divided into multiple sub-areas, and the SO2 adsorption amount of each sub-area is calculated according to the SO2 removal equation. The SO2 content at the flue gas outlet of the carbon-based desulfurization tower is obtained according to the SO2 in each sub-area. Finally, the feeding speed of the activated carbon in the carbon-based desulfurization tower is adjusted so that the SO2 content at the flue gas outlet of the carbon-based desulfurization tower meets the operating requirements.

[0115] 302) Based on step 301), the HCl adsorption amount of each sub-region is calculated according to the SO2 adsorption amount of each sub-region and the competitive removal equation of SO2 and HCl. Then, the HCl content at the flue gas outlet of the carbon-based desulfurization tower is obtained according to the HCl adsorption amount of each sub-region, and finally, the feeding speed of the activated carbon in the carbon-based desulfurization tower is adjusted so that the HCl content at the flue gas outlet of the carbon-based desulfurization tower meets the working condition requirements. Finally, the SO2 content and HCl content at the flue gas outlet of the carbon-based desulfurization tower both meet the working condition requirements.

[0116] Example 7

[0117] Repeat Example 6, except that step 301) is specifically as follows: divide the height of the activated carbon bed into m layers in the vertical direction, divide the width of the activated carbon bed into n columns in the horizontal direction, and then divide the entire activated carbon bed into (m×n) sub-regions. Apply the SO2 removal equation to each sub-region in turn, and iteratively calculate the SO2 adsorption amount and SO2 concentration of each sub-region according to the SO2 removal equation. Among them, the activated carbon adsorption amount Q[0, j] of the sub-region at the activated carbon inlet of the carbon-based desulfurization tower is 0, and the SO2 concentration C[i, 0] of the sub-region at the flue gas inlet of the carbon-based desulfurization tower is C0. Then:

[0118] Q[i,j]=Q[i-1,j]+dQ[i,j]...(3).

[0119] dt=(h / m) / v…(4).

[0120] C[i,j]=C[i,j-1]-dC[i,j]...(5).

[0121] Where: Q[i, j] represents the SO2 adsorption amount of the sub-region corresponding to the position of the i-th grid in the vertical height direction and the j-th grid in the horizontal width direction of the activated carbon bed, mg / g. dQ[i, j] represents the additional SO2 adsorption amount of activated carbon in the current sub-region, mg / g. C[i, j] represents the SO2 concentration of the sub-region corresponding to the position of the i-th grid in the vertical height direction and the j-th grid in the horizontal width direction of the activated carbon bed, mg / m 3 dC[i, j] represents the reduced SO2 concentration under the adsorption of activated carbon in the current sub-region, mg / m 3 . Where i≤m, j≤n. dt represents the residence time of activated carbon in the current sub-area, h. h is the height of the activated carbon bed in the carbon-based desulfurization tower, m. v is the activated carbon feed rate of the corresponding sub-area in the carbon-based desulfurization tower, m / h. C0 is the SO2 concentration at the flue gas inlet of the carbon-based desulfurization tower, mg / m 3 .

[0122] Example 8

[0123] Example 7 is repeated, except that in step 301), the feeding rate of activated carbon in the carbon-based desulfurization tower is adjusted so that the SO2 content at the flue gas outlet of the carbon-based desulfurization tower meets the working condition requirements, specifically:

[0124] 301a) According to the SO2 concentration at the flue gas inlet of the carbon-based desulfurization tower, combined with the proportional relationship of the activated carbon feeding speed of the front unit bed layer, the middle unit bed layer, and the rear unit bed layer, and the SO2 concentration at the flue gas outlet of the carbon-based desulfurization tower is less than C 目The theoretical feed rate of activated carbon in the front unit bed layer, the middle unit bed layer, and the rear unit bed layer is calculated by the SO2 removal equation as the target. After adjusting the actual feed rate of activated carbon in the front unit bed layer, the middle unit bed layer, and the rear unit bed layer to be consistent with the theoretical feed rate, step 302b) is performed.

[0125] 301b) Real-time detection of the real-time SO2 concentration at the flue gas outlet of the carbon-based desulfurization tower is recorded as C 实 Compare C 实 The target upper limit of SO2 concentration at the flue gas outlet of the carbon-based desulfurization tower is C 目 If C 实 <C 目 , record the activated carbon feeding rate of each unit bed layer, then slightly reduce the activated carbon feeding rate of each unit bed layer, then detect the adjusted real-time SO2 concentration, and continue to compare the adjusted real-time SO2 concentration with the target upper limit C of SO2 concentration. 目 Repeat this step until the real-time SO2 concentration C at the flue gas outlet of the carbon-based desulfurization tower is 实 ≥C 目 At this time, the last recorded C 实 <C 目 The carbon feeding rate of each unit bed layer at this time is the optimal feeding rate, thereby determining the optimal desulfurization circulation amount of activated carbon.

[0126] If the real-time SO2 concentration is C 实 ≥C 目 , slightly increase the activated carbon feeding rate of each unit bed layer, record the activated carbon feeding rate of each unit bed layer, then detect the adjusted real-time SO2 concentration, and continue to compare the adjusted real-time SO2 concentration with the target upper limit C of SO2 concentration. 目 Repeat this step until the real-time SO2 concentration C at the flue gas outlet of the carbon-based desulfurization tower is 实 <C 目 At this time, the last recorded activated carbon feeding rate of each unit bed is the optimal feeding rate, thereby determining the optimal desulfurization cycle of activated carbon. 目 ≤35mg / Nm 3 .

[0127] Example 9

[0128] Example 8 is repeated, except that in step 302), the feed rate of activated carbon in the carbon-based desulfurization tower is adjusted so that the HCl content at the flue gas outlet of the carbon-based desulfurization tower meets the operating conditions. Specifically, when the feed rate of activated carbon in each unit bed of the carbon-based desulfurization tower is the operating condition of the optimal desulfurization cycle of activated carbon, the current SO2 adsorption amount of each unit bed is calculated based on the feed rate of activated carbon in each unit bed and the SO2 removal equation (it should be noted that the calculation of the SO2 adsorption amount of each unit bed is obtained by applying the SO2 removal equation and the SO2 and HCl competitive removal equation to the sub-areas divided by the unit bed). Then, the current HCl adsorption amount of each unit bed is calculated based on the SO2 adsorption amount of each unit bed and the SO2 and HCl competitive removal equation. The HCl concentration at the flue gas outlet of the current carbon-based desulfurization tower is calculated and recorded as C s Compare C s The target upper limit of HCl concentration is C 标 If C s <C 标 , then maintain the current working condition. s ≥C 标 , slightly increase the activated carbon feeding rate of each unit bed layer, record the activated carbon feeding rate of each unit bed layer, and then calculate the HCl concentration at the flue gas outlet of the carbon-based desulfurization tower after adjustment, and continue to compare the HCl concentration C at the flue gas outlet of the carbon-based desulfurization tower after adjustment s The target upper limit of HCl concentration is C 标 Repeat this step until the HCl concentration C at the flue gas outlet of the carbon-based desulfurization tower is s <C 标 At this time, the last recorded activated carbon feeding rate of each unit bed is the optimal feeding rate, thereby determining the optimal desulfurization and dechlorination cycle of activated carbon. 标 ≤4mg / Nm 3 .

[0129] Application Example 1

[0130] The method for controlling the simultaneous desulfurization and dechlorination of a carbon-based flue gas purification system with multiple pollutants described in Example 9 was used to treat the sintering flue gas of a steel smelter. It was detected that the SO2 concentration in the sintering flue gas to be treated was about 380 ppm (about 1086 mg / m 3 ), HCl concentration is about 30ppm (about 48.8mg / m 3 ); the water content is about 10%, the oxygen content is about 17%, and the flue gas temperature is about 413K. Under this condition, the reaction order of SO2 is l = 0.8, the correction term α = 0.22, and K1 = 7.2h -1 , K2=0.008h -1, the activation energy of activated carbon is Ea = 0.89 kJ / mol, the gas constant is R = 8.314 J / (mol·K), and the adsorption rate of activated carbon to SO2 in the first stage of sulfuric acid accumulation process is K1 = 7.2 h -1 In the third stage of the sulfuric acid accumulation process in the activated carbon adsorption rate curve for SO2, the adsorption rate of SO2 is K2 = 0.008h -1 , the apparent saturated adsorption capacity of activated carbon for SO2 is Qs = 71 mg / g. The horizontal thickness of the front unit bed of the carbon-based desulfurization tower is L1 = 0.16m, the horizontal thickness of the middle unit bed is L2 = 0.72m, and the horizontal thickness of the rear unit bed is L3 = 0.72mm. The total height of the activated carbon bed in the carbon-based desulfurization tower is H = 24m, and the total width perpendicular to the horizontal direction is W = 9m. Under the structure of the above-mentioned carbon-based desulfurization tower, the SO2 concentration at the flue gas inlet of the carbon-based desulfurization tower is divided into 10 intervals of 0-100ppm, 100-200ppm,..., 900-1000ppm, combined with the original feed rate ratio of the activated carbon in the front, middle and rear unit beds of the carbon-based desulfurization tower V1:V2:V3 = 6:2:1, and the SO2 concentration at the flue gas outlet of the carbon-based desulfurization tower is less than C 目 (C 目 =35mg / Nm 3 ) as the target, the front unit bed of the carbon-based desulfurization tower is divided into 12 layers and 1 column with a total of 12 sub-areas, and the middle and rear unit beds of the carbon-based desulfurization tower are divided into 12 layers and 4 columns with 48 sub-areas each. The SO2 removal equation described in the above formula (1) is adapted to all sub-areas in turn, and then the initial theoretical feed rate of activated carbon in each unit bed within the corresponding inlet SO2 concentration range is calculated, and the desulfurization strategy table of activated carbon feed rate is obtained. The desulfurization strategy table is as follows:

[0131]

[0132] In this application example, since the SO2 concentration at the flue gas inlet of the carbon-based desulfurization tower is about 380ppm, according to the above desulfurization strategy table of activated carbon feeding speed, the theoretical feeding speeds of activated carbon in each unit bed of the carbon-based desulfurization tower are respectively: V1 = 0.33m / h, V2 = 0.11m / h, V3 = 0.055m / h. After adjusting the actual feeding speed ratio of the activated carbon in the front, middle and rear unit beds of the carbon-based desulfurization tower V1:V2:V3 = 0.33:0.11:0.055, the flue gas is continued to be treated, and then the real-time SO2 concentration C at the flue gas outlet of the desulfurization tower is detected. 实 =26.85mg / m 3 .

[0133] Obviously, C 实 <C 目, record the current activated carbon feeding speed V1, V2, V3 of each unit bed, and then slightly reduce the activated carbon feeding speed of each unit bed at the front, middle and back of the carbon-based desulfurization tower according to the proportional relationship of the feeding speed of each unit bed (that is, V1, V2, V3 are reduced by 0.018m / h, 0.006m / h, 0.003m / h on the original basis respectively); and calculate the adjusted real-time SO2 concentration at the flue gas outlet of the carbon-based desulfurization tower according to the activated carbon feeding speed of each unit bed after adjustment, and compare the adjusted real-time SO2 concentration with the upper limit of SO2 concentration C 目 Repeat this step until the real-time SO2 concentration C at the flue gas outlet of the carbon-based desulfurization tower is detected. 实 ≥C 目 At this time, the last recorded C 实 <C 目 The activated carbon feeding rate of each unit bed layer at this time is V1′=0.474m / h, V2′=0.158m / h, V3′=0.079m / h, which is the optimal desulfurization feeding rate. The activated carbon feeding rate of each unit bed layer at the front, middle and rear of the carbon-based desulfurization tower is adjusted and maintained to the optimal desulfurization feeding rate.

[0134] The activated carbon feeding rate of each unit bed in the front, middle and back of the carbon-based desulfurization tower is the optimal feeding rate and the real-time SO2 concentration C at the flue gas outlet of the carbon-based desulfurization tower is 实 <C 目 Under the condition of , combined with the HCl concentration at the flue gas outlet of the carbon-based desulfurization tower being less than C 标 (C 标 =4mg / Nm 3 ) is taken as the target, the front unit bed of the carbon-based desulfurization tower is divided into 12 layers and 1 column with a total of 12 sub-areas, and the middle and rear unit beds of the carbon-based desulfurization tower are divided into 12 layers and 4 columns with 48 sub-areas each. The SO2 adsorption amount of each sub-area is calculated according to the SO2 removal equation described in the above formula (1), and then the HCl adsorption amount of each sub-area is calculated according to the competitive removal equation of SO2 and HCl described in the above formula (2), and then the preliminary theoretical feed rate of activated carbon of each unit bed in the corresponding inlet HCl concentration range is calculated, and the dechlorination strategy table of activated carbon feed rate is further obtained. The dechlorination strategy table is as follows:

[0135]

[0136] In this application example, since the SO2 concentration of the flue gas inlet is 380 mg / Nm 3Under the condition of , the optimal desulfurization feed rate of activated carbon in each unit bed of the carbon-based desulfurization tower is V1′=0.474m / h, V2′=0.158m / h, V3′=0.079m / h. According to the dechlorination strategy table of the above activated carbon feed rate, the tolerance range of the upper limit of the flue gas inlet HCl concentration under this condition is between 2.5 and 23.81ppm (less than the measured 30ppm). At this activated carbon feed rate, the real-time HCl concentration C at the flue gas outlet of the desulfurization tower is detected. s =5.08mg / m 3 .

[0137] Obviously, under this condition, C s >C 标 , record the current activated carbon feeding speed V1′, V2′, V3′ of each unit bed, and then increase the activated carbon feeding speed of each unit bed at the front, middle and rear of the carbon-based desulfurization tower slightly according to the proportional relationship of the feeding speed of each unit bed (that is, V1′, V2′, V3′ are increased by 0.018m / h, 0.006m / h, and 0.003m / h on the original basis, respectively); and calculate the adjusted real-time HCl concentration at the flue gas outlet of the carbon-based desulfurization tower according to the activated carbon feeding speed of each unit bed after adjustment, and compare the adjusted real-time HCl concentration with the upper limit of HCl concentration C 标 Repeat this step until the real-time HCl concentration C at the flue gas outlet of the carbon-based desulfurization tower is detected. s <C 标 At this time, the last recorded C s <C 标 The activated carbon feeding rates of each unit bed layer at this time are V1″=0.51m / h, V2″=0.17m / h, and V3″=0.085m / h, which are the optimal feeding rates for desulfurization and dechlorination. The activated carbon feeding rates of the front, middle, and rear unit beds of the carbon-based desulfurization tower are adjusted and maintained to be the optimal feeding rates for desulfurization and dechlorination.

Claims

1. A method for controlling the simultaneous desulfurization and dechlorination of a multi-pollutant flue gas carbon-based purification system, characterized in that: The method comprises the following steps: 1) The original flue gas is subjected to adsorption and purification treatment in a carbon-based adsorption tower and then discharged in compliance with the emission standards; based on the adsorption rate curve of activated carbon to SO2 in the carbon-based desulfurization tower, an SO2 removal equation is constructed; 2) Based on the competitive adsorption curve of activated carbon for SO2 and HCl in the carbon-based desulfurization tower, the competitive removal equation of SO2 and HCl was constructed; 3) The theoretical feed rate of activated carbon under the condition that the SO2 and HCl contents at the flue gas outlet of the carbon-based desulfurization tower meet the working conditions is calculated based on the SO2 removal equation and the competitive removal equation of SO2 and HCl; the actual feed rate of activated carbon in the carbon-based desulfurization tower is adjusted to be consistent with the calculated theoretical feed rate.

2. The method according to claim 1, characterized in that: In step 1), the removal equation of SO2 is constructed as follows: 101) According to the variation law of the SO2 concentration ratio between the flue gas outlet and the flue gas inlet of the carbon-based desulfurization 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; 102) According to the variation law of the adsorption amount of SO2 by activated carbon in the carbon-based desulfurization tower over time, the adsorption rate curve of activated carbon to SO2 is drawn; 103) Based on the characteristic that the adsorption rate of SO2 by activated carbon is constant in the first and third stages and the adsorption rate curve of SO2 by activated carbon, the removal equation of SO2 by activated carbon in a carbon-based desulfurization tower is constructed.

3. The method according to claim 1 or 2, characterized in that: The removal equation of SO2 is: In formula (1): dQ / dt is the increment of the amount of SO2 adsorbed by activated carbon over time, mg / (g·h); Q is the amount of SO2 adsorbed by activated carbon at the start time during the calculation period, mg / g; t is the residence time of activated carbon in the carbon-based desulfurization tower, h; α is the correction term; C is the SO2 concentration in the original 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 original flue gas temperature, K; K1 is the adsorption rate of SO2 in the first stage of sulfuric acid accumulation process in the adsorption rate curve of activated carbon to SO2, h -1 ; K2 is the adsorption rate of SO2 in the third stage of sulfuric acid accumulation process in the adsorption rate curve of activated carbon for SO2, h -1 ; Qs is the apparent saturated adsorption capacity of activated carbon for SO2, mg / g.

4. The method according to any one of claims 1 to 3, characterized in that: In step 1), the competitive removal equation between SO2 and HCl is constructed as follows: 201) According to the adsorption rate curve of activated carbon to SO2 in a carbon-based desulfurization tower, activated carbon adsorbing different amounts of SO2 is obtained; 202) According to the variation law of the maximum adsorption amount of HCl by activated carbon that has adsorbed different amounts of SO2, a competitive adsorption curve of SO2 and HCl by activated carbon is plotted; then, a competitive removal equation of SO2 and HCl is constructed based on the competitive adsorption curve of SO2 and HCl by activated carbon.

5. The method according to claim 1 or 4, characterized in that: The competitive removal equation of SO2 and HCl is: Q h =-0.025+2.5 / (1+exp(Q-28.25) / 3.75) (2); In formula (2): Q h is the adsorption capacity of HCl by activated carbon, mg / g; Q is the adsorption capacity of SO2 by activated carbon, mg / g.

6. The method according to any one of claims 1 to 5, characterized in that: In step 1), a flue gas inlet and a flue gas outlet are respectively opened on both side walls in the horizontal direction of the carbon-based desulfurization tower, and an activated carbon inlet and an activated carbon outlet are respectively opened on the top and bottom in the vertical direction of the carbon-based desulfurization tower, and the contact mode between the original flue gas and the activated carbon in the carbon-based desulfurization tower is cross-flow contact; Preferably, in step 1), according to the direction of the flue gas, the activated carbon bed in the carbon-based desulfurization tower is divided into a front unit bed, a middle unit bed, and a rear unit bed; the activated carbon feeding rate of the front unit bed is set to V1, the activated carbon feeding rate of the middle unit bed is set to V2, and the activated carbon feeding rate of the rear unit bed is set to V3; Among them, V1:V2:V3=5.5-6.5:1.5-2.5:1, preferably 5.7-6.3:1.8-2.2:

1.

7. The method according to claim 6, characterized in that: Step 3) includes: 301) The activated carbon bed in the carbon-based desulfurization tower is divided into a plurality of sub-areas, and the SO2 adsorption amount of each sub-area is calculated according to the SO2 removal equation, and the SO2 content at the flue gas outlet of the carbon-based desulfurization tower is obtained according to the SO2 adsorption amount of each sub-area, and finally the feeding speed of the activated carbon in the carbon-based desulfurization tower is adjusted so that the SO2 content at the flue gas outlet of the carbon-based desulfurization tower meets the working condition requirements; 302) On the basis of step 301), the HCl adsorption amount of each sub-region is calculated according to the SO2 adsorption amount of each sub-region and the competitive removal equation of SO2 and HCl; then, the HCl content at the flue gas outlet of the carbon-based desulfurization tower is obtained according to the HCl adsorption amount of each sub-region, and finally, the feeding speed of the activated carbon in the carbon-based desulfurization tower is adjusted so that the HCl content at the flue gas outlet of the carbon-based desulfurization tower meets the operating conditions; finally, the SO2 content and HCl content at the flue gas outlet of the carbon-based desulfurization tower both meet the operating conditions.

8. The method according to claim 7, characterized in that: Step 301) is specifically as follows: the height of the activated carbon bed is divided into m layers in the vertical direction, and the width of the activated carbon bed is divided into n columns in the horizontal direction, and then the entire activated carbon bed is divided into (m×n) sub-areas; the SO2 removal equation is applied to each sub-area in turn, and the SO2 adsorption amount and SO2 concentration of each sub-area are iteratively calculated according to the SO2 removal equation; wherein, the activated carbon adsorption amount Q[0, j] of the sub-area at the inlet of the activated carbon of the carbon-based desulfurization tower is 0, and the SO2 concentration C[i, 0] of the sub-area at the inlet of the flue gas of the carbon-based desulfurization tower is =C0; then: Q[i,j]=Q[i-1,j]+dQ[i,j]...(3); dt=(h / m) / v…(4); C[i,j]=C[i,j-1]-dC[i,j]...(5); Where: Q[i, j] represents the SO2 adsorption capacity of the sub-region corresponding to the position of the i-th grid in the vertical height direction and the j-th grid in the horizontal width direction of the activated carbon bed, mg / g; dQ[i, j] represents the additional SO2 adsorption capacity of the activated carbon in the current sub-region, mg / g; C[i, j] represents the SO2 concentration of the sub-region corresponding to the position of the i-th grid in the vertical height direction and the j-th grid in the horizontal width direction of the activated carbon bed, mg / m 3 ; dC[i, j] represents the reduced SO2 concentration under the adsorption of activated carbon in the current sub-region, mg / m 3 ; Where i≤m, j≤n; dt represents the residence time of activated carbon in the current sub-area, h; h is the height of the activated carbon bed in the carbon-based desulfurization tower, m; v is the activated carbon feeding speed of the corresponding sub-area in the carbon-based desulfurization tower, m / h; C0 is the SO2 concentration at the flue gas inlet of the carbon-based desulfurization tower, mg / m 3 .

9. The method according to claim 7 or 8, characterized in that: In step 301), the feeding speed of activated carbon in the carbon-based desulfurization tower is adjusted so that the SO2 content at the flue gas outlet of the carbon-based desulfurization tower meets the working condition requirements, specifically: 301a) According to the SO2 concentration at the flue gas inlet of the carbon-based desulfurization tower, combined with the proportional relationship of the activated carbon feeding speed of the front unit bed layer, the middle unit bed layer, and the rear unit bed layer, and the SO2 concentration at the flue gas outlet of the carbon-based desulfurization tower is less than C 目 The theoretical feed rate of activated carbon in the front unit bed layer, the middle unit bed layer, and the rear unit bed layer is calculated by the SO2 removal equation as the target; the actual feed rate of activated carbon in the front unit bed layer, the middle unit bed layer, and the rear unit bed layer is adjusted to be consistent with the theoretical feed rate and then step 302b) is performed; 301b) Real-time detection of the real-time SO2 concentration at the flue gas outlet of the carbon-based desulfurization tower is recorded as C 实 ; Compare C 实 The target upper limit of SO2 concentration at the flue gas outlet of the carbon-based desulfurization tower is C 目 The size of C 实 <C 目 , record the activated carbon feeding rate of each unit bed layer, then slightly reduce the activated carbon feeding rate of each unit bed layer, then detect the adjusted real-time SO2 concentration, and continue to compare the adjusted real-time SO2 concentration with the target upper limit C of SO2 concentration. 目 Repeat this step until the real-time SO2 concentration C at the flue gas outlet of the carbon-based desulfurization tower is 实 ≥C 目 At this time, the last recorded C 实 <C 目 The carbon feeding rate of each unit bed layer at this time is the optimal feeding rate, so as to determine the optimal desulfurization circulation amount of activated carbon; If the real-time SO2 concentration is C 实 ≥C 目 , slightly increase the activated carbon feeding rate of each unit bed layer, record the activated carbon feeding rate of each unit bed layer, then detect the adjusted real-time SO2 concentration, and continue to compare the adjusted real-time SO2 concentration with the target upper limit C of SO2 concentration. 目 Repeat this step until the real-time SO2 concentration C at the flue gas outlet of the carbon-based desulfurization tower is 实 <C 目 At this time, the last recorded activated carbon feeding rate of each unit bed is the optimal feeding rate, so as to determine the optimal desulfurization cycle of activated carbon; among them, C 目 ≤35mg / Nm 3 .

10. The method according to claim 9, characterized in that: In step 302), the activated carbon feeding rate in the carbon-based desulfurization tower is adjusted so that the HCl content at the flue gas outlet of the carbon-based desulfurization tower meets the working condition requirements. Specifically, under the working condition that the activated carbon feeding rate of each unit bed in the carbon-based desulfurization tower is the optimal desulfurization circulation amount of the activated carbon, the current SO2 adsorption amount of each unit bed is calculated according to the activated carbon feeding rate of each unit bed at this time and the SO2 removal equation; then, the HCl adsorption amount of the current unit bed is calculated according to the SO2 adsorption amount of each unit bed and the competitive removal equation of SO2 and HCl; and then the HCl concentration at the flue gas outlet of the current carbon-based desulfurization tower is calculated and recorded as C s ; Compare C s The target upper limit of HCl concentration C 标 The size of C s <C 标 , then maintain the current working condition; if C s ≥C 标 , slightly increase the activated carbon feeding rate of each unit bed layer, record the activated carbon feeding rate of each unit bed layer, and then calculate the HCl concentration at the flue gas outlet of the carbon-based desulfurization tower after adjustment, and continue to compare the HCl concentration C at the flue gas outlet of the carbon-based desulfurization tower after adjustment s The target upper limit of HCl concentration C 标 Repeat this step until the HCl concentration C at the flue gas outlet of the carbon-based desulfurization tower is s <C 标 At this time, the last recorded activated carbon feeding rate of each unit bed is the optimal feeding rate, so as to determine the optimal desulfurization and dechlorination cycle of activated carbon; among them, C 标 ≤4mg / Nm 3 .

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