Method for co-governing multiple pollutants in carbon dioxide capture from sintering flue gas

Abstract

A method for simultaneously treating multiple pollutants in carbon dioxide capture in sintering flue gas, the method comprising: 1) according to the running direction of the sintering trolley, the wind box is divided into a front wind box and a rear wind box, and the sintering flue gas in the front wind box and the sintering flue gas in the rear wind box are treated respectively. 2) the decarburization series flue gas is sequentially subjected to heating, dust removal, desulfurization and denitrification and cooling treatment, and then the CO2 in the decarburization series flue gas is captured by a capture agent and discharged through a chimney; 3) the non-decarburization series flue gas is sequentially subjected to dust removal and desulfurization and denitrification treatment and discharged through a chimney. According to the flue gas release law of the sintering process, the flue gas is divided into decarburization series flue gas and non-decarburization series flue gas for purification, the flue gas purification efficiency is improved, and the flue gas waste heat is fully utilized according to the performance of the flue gas, and the resources are fully utilized.

Description

Technical Field

[0001] This invention relates to a method for treating multiple pollutants in sintering flue gas, specifically a method for treating multiple pollutants in sintering flue gas by capturing carbon dioxide, belonging to the field of sintering flue gas treatment. Background Technology

[0002] Carbon peaking and carbon neutrality have become a broad global consensus. my country attaches great importance to promoting and implementing the "dual carbon" goals and tasks, and has repeatedly emphasized the importance and necessity of doing a good job in carbon peaking and carbon neutrality at important meetings. It has also introduced measures to implement these goals, and low-carbon policies will gradually shift from relative constraints to absolute constraints.

[0003] CO2 capture, conversion, and utilization are feasible technological options for the low-carbon transformation of industries such as steel and cement, which are difficult to reduce emissions. Currently, the main CO2 capture technologies in the steel industry include waste heat and energy recovery technology. The use of recovery technology reduces fossil fuel consumption and effectively reduces CO2 emissions. Secondly, there is CCUS technology, which is one of the key technologies for addressing global climate change. Carbon dioxide capture methods mainly include pre-combustion capture, oxy-fuel combustion, and post-combustion capture. Post-combustion capture technology has the fastest industrialization process and is already in the industrial application stage, while pre-combustion capture and oxy-fuel combustion capture technologies are still in the industrial demonstration and pilot-scale demonstration stages, respectively. Post-combustion capture technology separates carbon dioxide from flue gas in the capture system, forming a high concentration of carbon dioxide, which is then utilized.

[0004] The most mature application of post-combustion capture systems is the circulating adsorption system. This system uses the liquid-phase adsorption of organic amines and selective chemical reactions to remove readily soluble organic amine components from the gas phase. Organic amine systems mainly include absorption devices, desorption devices (regeneration devices), energy exchange devices (such as lean and rich liquid heat exchangers, lean liquid coolers, condensers, and reflux condensers), system power devices (such as lean liquid pumps, auxiliary liquid pumps, reflux pumps, booster pumps, and fans), and system auxiliary devices (such as flue gas pretreatment devices, replenishment devices, and filtration devices). However, the typical primary amine solvent, monoethanolamine (MEA), has an adsorption temperature between 40-70℃, while regeneration requires heating to around 120℃. Regeneration energy consumption (4.1 Gt / t CO2) accounts for more than 60% of the total energy consumption of the entire decarbonization system and 50-60% of the operating cost of the CO2 capture process. The excessively high energy consumption of the organic amine solvent regeneration process seriously hinders the industrial application of this technology.

[0005] Currently, the steel industry mainly uses post-combustion carbon capture, with common technologies including physical adsorption, chemical absorption, and membrane separation. These technologies effectively capture carbon dioxide emissions from various processes. However, sintering flue gas is large in volume and has a complex composition, containing SO2 and NO. xConventional pollutants such as dust and particulate matter, as well as gases like CO2, H2O, and N2, severely impact the environment. Furthermore, due to the high emission temperature of sintering flue gas, current conventional CO2 capture technologies are not well-suited for application. Therefore, a feasible, low-cost, and highly efficient CO2 capture process for sintering flue gas, targeting the complex components in the flue gas, is needed, along with methods for treating other pollutants. Summary of the Invention

[0006] To address the shortcomings of existing CO2 capture technologies and the lack of comprehensive treatment methods for carbon dioxide, sulfides, and nitrogen oxides in flue gas, this invention proposes a method for the synergistic treatment of multiple pollutants through carbon dioxide capture in sintering flue gas. Based on the release patterns of sintering flue gas, the flue gas is divided into decarbonized and non-decarbonized series, and different purification processes are set according to the concentration of pollutants in the flue gas, with precise control over the amount of activated carbon and ammonia introduced.

[0007] A method for treating multiple pollutants in sintering flue gas by capturing carbon dioxide, the method comprising the following steps:

[0008] 1) Based on the running direction of the sintering trolley, the air box below the sintering machine is divided into a front air box and a rear air box. The sintering flue gas in the front air box and the sintering flue gas in the rear air box are treated separately. The sintering flue gas in the front air box is mixed to obtain decarburized flue gas, and the sintering flue gas in the rear air box is mixed to obtain non-decarburized flue gas.

[0009] 2) After the decarbonized flue gas is successively subjected to heating, dust removal, desulfurization and denitrification and cooling treatment, the CO2 in the decarbonized flue gas is then captured by a capture agent and discharged through the chimney.

[0010] 3) The non-decarbonized flue gas is successively treated by dust removal and desulfurization and denitrification before being discharged through a chimney.

[0011] Preferably, the method further includes: 4) thermally regenerating the trapping agent after adsorbing carbon dioxide in step 2) to obtain high-purity carbon dioxide and regenerated trapping agent, and returning the regenerated trapping agent to step 2) for recycling.

[0012] As a preferred option, a portion of the high-temperature flue gas in the rear air box is indirectly heated with the carbon dioxide-adsorbed scavenger to achieve thermal regeneration of the scavenger.

[0013] Preferably, the decarbonized flue gas in step 1) is characterized by: a flue gas temperature of 50–100°C, a CO2 concentration ≥7% (preferably CO2 concentration ≥8%), and an SO2 concentration ≤25 mg / Nm³. 3 (Preferred SO2 concentration ≤ 20 mg / Nm) 3When the flue gas in the wind box is determined to be decarbonized flue gas, the wind box is assigned to the front wind box; the non-decarbonized flue gas mentioned in step 1) is defined as: when the temperature of the flue gas in the wind box is 50-100℃, or the CO2 concentration is ≤7% (preferably CO2 concentration ≤8%), or the SO2 concentration is ≥25mg / Nm³. 3 (Preferred SO2 concentration ≥ 20 mg / Nm) 3 When the flue gas in the wind box is determined to be non-decarbonized flue gas, the wind box is assigned to the rear wind box.

[0014] Preferably, the CO2 trapping agent in step 2) is an organic amine solution; preferably MDEA, DPMA, MEA or a combination thereof;

[0015] Preferably, the concentration of the organic amine solution is 20–60 wt.%, and the solvent is water, a polar physical solvent, or a combination thereof.

[0016] Preferably, the heating in step 2) involves heating the decarbonized flue gas to 105–150°C, more preferably 110–120°C.

[0017] Preferably, the desulfurization and denitrification in step 2) involves using activated carbon to adsorb and decarbonize small amounts of sulfur dioxide and nitrogen oxides in the flue gas.

[0018] Preferably, the cooling in step 2) is to cool the flue gas after desulfurization and denitrification to 35-60°C, more preferably 40-50°C.

[0019] Preferably, the dust removal described in steps 2) and 3) is an electrostatic precipitator.

[0020] Preferably, the desulfurization and denitrification in step 3) involves using activated carbon to adsorb sulfur dioxide and a small amount of nitrogen oxides in the non-decarbonized flue gas.

[0021] Preferably, the temperature rise in step 2) is a temperature rise after heat exchange between the decarbonized flue gas and the non-decarbonized flue gas; preferably, the temperature of the non-decarbonized flue gas is reduced to 105-150°C after heat exchange, and more preferably to 110-130°C.

[0022] Preferably, the activated carbon control in the desulfurization and denitrification process in steps 2) and 3) is as follows: the amount of activated carbon required for the desulfurization and denitrification process is calculated based on the flue gas denitrification, and the amount of activated carbon required for the flue gas desulfurization and denitrification process is calculated based on the flue gas desulfurization.

[0023] Preferably, in the desulfurization and denitrification process, the concentration of SO2 and NO in the flue gas is considered. x Concentration calculation: the amount of ammonia gas required to be injected during the desulfurization and denitrification process.

[0024] Preferably, the calculation of the required activated carbon addition during the desulfurization and denitrification process based on flue gas denitrification specifically involves:

[0025] The flow rate of the flue gas is measured as Q1, m. 3 Based on the amount of activated carbon required for flue gas denitrification, the required amount of activated carbon to purify the flue gas can be calculated:

[0026]

[0027] In the formula, Y is the denitrification rate of flue gas, %; sv0 is the space velocity of activated carbon adsorbing nitrogen oxides, h. -1 x is a multiple of the space velocity; n is the number of adsorption units in the adsorption tower; the volume of activated carbon in a single adsorption unit in the adsorption tower is v, m. 3 Based on the required denitrification rate, the amount of activated carbon required for purifying flue gas, n*v, is calculated using Equation 1.

[0028] The value of Y is determined by the flue gas purification requirements in the actual process; the value of sv0 ranges from 200 to 500 h. -1 Preferably 250-300h -1 The value of x ranges from 0.5 to 1.2, preferably from 0.6 to 1; n is an integer greater than or equal to 1.

[0029] Preferably, the required circulating amount of activated carbon during the flue gas desulfurization and denitrification process is calculated based on the flue gas desulfurization process, specifically as follows:

[0030] The flow rate of the flue gas is measured as Q1, m. 3 The required circulating amount of activated carbon for flue gas purification can be calculated based on the amount of activated carbon required for flue gas desulfurization.

[0031]

[0032] In the formula, W is the circulating volume of activated carbon in the adsorption tower, in g; C0 is the SO2 concentration in the flue gas at the inlet of the adsorption tower, in mg / Nm³. 3 C1 represents the SO2 concentration in the gas at the outlet of the adsorption tower, and its value ranges from 0 to 35 mg / Nm³. 3 ; s1 represents the adsorption capacity of activated carbon for SO2, in mg / g.

[0033] Preferably, the amount of ammonia gas required for the desulfurization and denitrification process is calculated based on the SO2 and NOx concentrations in the flue gas, specifically as follows:

[0034]

[0035] In the formula, C3 represents the amount of ammonia required for desulfurization and denitrification, in mg / Nm³. 3 C0 represents the SO2 concentration at the inlet of the adsorption tower; C2 represents the NO concentration at the inlet of the adsorption tower. xconcentration.

[0036] Preferably, the thermal regeneration treatment of the trapping agent in step 4) is as follows: the trapping agent is heated to 110-130°C and regenerated for 0.3-1 hour to obtain a regenerated trapping agent.

[0037] According to a second embodiment of the present invention, a treatment system for capturing carbon dioxide and co-treating multiple pollutants in sintering flue gas is provided.

[0038] A system for the coordinated treatment of carbon dioxide capture and multiple pollutants in sintering flue gas is disclosed. The system includes a sintering machine, a decarbonization series flue gas duct, a non-decarbonization series flue gas duct, a heating device, a first desulfurization and denitrification device, a second desulfurization and denitrification device, a cooling device, and a carbon dioxide capture device. The bottom air box of the sintering machine is divided into a front air box and a rear air box, with the front air box connected to the decarbonization series flue gas duct and the rear air box connected to the non-decarbonization series flue gas duct. The flue gas outlet of the decarbonization series flue gas duct is connected to the flue gas inlet of the heating device via a first flue gas duct. The flue gas outlet of the heating device is connected to the flue gas inlet of the first desulfurization and denitrification device via a second flue gas duct. The flue gas inlet of the first desulfurization and denitrification device is connected to the flue gas inlet of the cooling device via a third flue gas duct; the flue gas outlet of the cooling device is connected to the flue gas inlet of the carbon dioxide capture device via a fourth flue gas duct. The non-decarbonization series flue gas duct is connected to the second desulfurization and denitrification device via a fifth flue gas duct. The flue gas outlet of the second desulfurization and denitrification device is connected to the chimney.

[0039] Preferably, the front air box comprises 1 / 4 to 3 / 4 of the air box closest to the head of the sintering machine, with the remaining air boxes forming the rear air boxes. Specifically, the front air box comprising 1 / 4 to 3 / 4 of the air box closest to the head of the sintering machine refers to the air box within this 1 / 4 to 3 / 4 radius when the total number of air boxes is 27 to 32. When the total number of air boxes is large, the front and rear air boxes are further divided based on the current operating conditions and the composition of the flue gas within the air boxes.

[0040] Preferably, the system further includes a central air box; the central air box includes a portion of the air box at the rear end of the front air box and / or a portion of the air box at the front end of the rear air box. Each of the central air boxes is connected to the decarbonized flue gas duct and the non-decarbonized flue gas duct via a three-way branch pipe, and a switching valve is provided at the three-way branch pipe.

[0041] Preferably, the first flue gas duct is equipped with a first dust removal device and a first fan.

[0042] Preferably, the fifth flue gas duct is equipped with a second dust removal device and a second fan.

[0043] Preferably, the decarbonized flue gas duct and / or the non-decarbonized flue gas duct are further equipped with a temperature detection device and a flue gas composition detection device.

[0044] Preferably, the system further includes a trap regeneration device. The trap outlet of the carbon dioxide capture device is connected to the trap inlet of the trap regeneration device. The flue gas outlet of the trap regeneration device is connected to a chimney. Preferably, the trap outlet of the trap regeneration device is connected to the trap inlet of the carbon dioxide capture device.

[0045] Preferably, the system further includes a heat exchanger connected to a portion of the tail section air box. The first flue gas duct passes through the heat exchanger. Preferably, the flue gas outlet of the heat exchanger is connected to the heat source inlet of the scavenger regeneration device. The heat source outlet of the scavenger regeneration device is connected to the second desulfurization and denitrification device.

[0046] In this invention, based on the principles of the sintering process, sintering involves uniformly mixing various iron-containing raw materials with specific amounts of fuel, solvent, recycled ore, and water, granulating the mixture, and spreading it evenly onto a sintering machine. Under the suction of the lower air box, ignition occurs on the surface of the material layer, followed by a high-temperature roasting reaction from top to bottom. Because the sintering process begins at the surface of the material layer and gradually proceeds downwards, there is a clear stratification along the height of the material layer during sintering. Based on the different temperature levels and physicochemical compositions of each layer, the sintering layer can be divided into five zones (e.g., ...). Figure 3 As shown in the diagram, from top to bottom, the zones are: sinter zone, combustion zone, drying and preheating zone, wet zone, and raw material zone.

[0047] In this invention, the flue gas release pattern during the sintering process was studied and summarized (e.g. Figures 4-8As shown in the diagram, when the total number of bellows is 28, the CO2 concentration is relatively high in the branch pipes of bellows 1 to 17, mainly between 8% and 14%. After bellows 17, the CO2 concentration gradually decreases to 0. From the perspective of the sintering process, the CO2 in the early stage originates from the fuel used in the iron ore sintering process. The significant decrease in CO2 content in the later stage is because the sintering endpoint is reached and the fuel is largely consumed. In addition, the SO2 concentration is very low in the branch pipes of bellows 0 to 15. The SO2 concentration in bellows 15 to 28 increases slowly, then releases rapidly, and then decreases slowly. This is mainly because the presence of the sintering wet zone causes a large amount of SO2 generated in the ore to be adsorbed. When the wet zone disappears, SO2 begins to be released in a concentrated manner. After the sintering process is completed, the SO2 concentration gradually decreases. Based on the above distribution patterns of SO2 and CO2, the flue gas in the bellows is divided into two series: the decarbonized series and the non-decarbonized series. Simultaneously, the temperature change and nitrogen oxide release patterns during sintering were analyzed. It was found that the nitrogen oxide concentration was higher in the decarbonized flue gas (temperature between 50 and 100°C) compared to the non-decarbonized flue gas, while the nitrogen oxide concentration was significantly lower. Therefore, the conditions for decarbonized flue gas are: flue gas temperature 50–100°C, CO2 concentration ≥8%, and SO2 concentration ≤20 mg / Nm³. 3 Furthermore, the volume of decarbonized flue gas accounts for approximately 30% of the total flue gas volume.

[0048] In this invention, based on the emission patterns of flue gas during sintering, decarbonized and non-decarbonized flue gas are treated separately. Since the decarbonized flue gas has a lower temperature and SO2 concentration, and activated carbon has a high SO2 adsorption efficiency, no additional desulfurization treatment is required; the ammonia injection amount needed for the decarbonized flue gas is directly calculated. Furthermore, since the non-decarbonized flue gas contains NO... x Low concentration, with an average concentration of 80–100 mg / Nm³ 3 According to the existing nitrogen oxide emission standards, a denitrification efficiency of 50% is sufficient. Calculate the required amount of activated carbon and ammonia injection for the non-decarbonized flue gas series.

[0049] In this invention, it was found that the adsorption conditions for CO2 by organic amine solutions are quite stringent. Under low-sulfur, low-temperature, low-dust, and high-CO2 environments, the CO2 capture efficiency increases significantly. Therefore, the decarbonized flue gas is heated to the denitrification temperature, then dusted and subjected to deep desulfurization and denitrification. CO2 capture is then performed after desulfurization and denitrification are completed. Non-decarbonized flue gas is cooled, dusted, and then subjected to desulfurization and denitrification. Research shows that the activated carbon denitrification efficiency is determined by factors such as space velocity, ammonia injection rate, reaction temperature, and activated carbon circulation rate. Table 1 shows the denitrification rate and its relationship with space velocity and inlet NO2 at 120℃ and an ammonia-to-nitrogen ratio of 1:1. x The relationship between concentration.

[0050] Table 1

[0051] Denitrification rate % 80 90 95 <![CDATA[NO x Standard value (mg / Nm) 3 ]]> 50 50 50 <![CDATA[NO x Upper limit mg / Nm 3 ]]> 250 500 1000

[0052] The relationship curve between denitrification rate and space velocity can be fitted from the data in Table 1:

[0053] Y = -0.3x + 1.1……(Equation 4)

[0054] In the formula, x is a multiple of the space velocity sv0, Y is the denitrification efficiency, and the value of sv0 ranges from 250 to 300 h⁻¹. -1 Based on Equation 4, and considering the relationship between denitrification rate and space velocity, ammonia injection rate, reaction temperature, activated carbon circulation rate, and actual operating conditions, Equation 1 is further fitted:

[0055]

[0056] In the formula, Y is the denitrification rate of the decarbonized flue gas, %; sv0 is the space velocity of activated carbon adsorbing nitrogen oxides, h. -1 x is a multiple of the space velocity sv0; n is the number of adsorption units in the adsorption tower; v is the volume of activated carbon packed in a single adsorption unit in the adsorption tower, in meters. 3 Where x is 0.5-1.2. The values ​​of Y and x are different for both decarbonized and non-decarbonized flue gas; because the concentration of nitrogen oxides at the outlet of the adsorption tower is limited to <50mg / Nm³. 3 Then, based on the concentration of nitrogen oxides in the decarbonized flue gas, the value of Y is determined, and the required amount of activated carbon can be calculated, which is the product of the number of adsorption units n in the adsorption tower and the loading volume v of the activated carbon in a single adsorption unit in the adsorption tower. Similarly, the activated carbon flow rate for denitrification of non-decarbonized flue gas can be obtained, and the amount of activated carbon required for desulfurization of non-decarbonized flue gas can be calculated using Equation 2. According to Equations 1, 2, 3, and 4, the amount of activated carbon flow rate in the flue gas purification process can be precisely controlled.

[0057] In this invention, the value range of Y is based on the NO content of the flue gas under actual operating conditions. x Concentration and NO in flue gas x The required concentration of NO is determined when NO x At higher concentrations, most of the NO needs to be purified. x The range of values ​​for Y decreases accordingly. For example, when NO x The concentration is 1000 mg / Nm 3 At that time, it should be reduced to 50 mg / Nm 3 The value of Y is 95% to 100% in the following cases. When NO... x When the concentration is low, only a portion of the NO needs to be purified. x That is, the range of values ​​for Y will increase accordingly. For example, when NO x The concentration is 100 mg / Nm 3At that time, it should be reduced to 50 mg / Nm 3 The value of Y is 50% to 100% in the following cases.

[0058] In this invention, in order to minimize the changes in flue gas composition caused by fluctuations in sinter or fuel composition, the flue gas in the wind box is determined to be a decarbonization series flue gas based on its composition. The wind box is then divided into a front wind box or a rear wind box and proceeds to the subsequent purification steps.

[0059] In this invention, the carbon dioxide-capturing agent is heated to 110-130°C and regenerated for 0.3-1 hour to obtain a regenerated capturing agent. The regenerated capturing agent is then recycled to step 2) for reuse, thereby reducing the cost of decarbonization.

[0060] In this invention, since the temperature of the sintering machine tail gas, i.e., the non-decarburized flue gas, is relatively high, the decarburized flue gas can be heated by exchanging heat with the non-decarburized flue gas. A heat exchange device is installed, and the first flue gas pipe passes through the heat exchange device, allowing the decarburized flue gas in the first flue gas pipe to exchange heat with the non-decarburized flue gas and increase its temperature. Alternatively, a portion of the non-decarburized flue gas can be optionally sent to the process of heating and regenerating the scavenging agent, making full use of the waste heat of the non-decarburized flue gas.

[0061] In this invention, the flue gas flow rate, circulation volume, etc., refer to the flow rate and circulation volume per unit time.

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] 1. The present invention provides a method for treating multiple pollutants by capturing carbon dioxide in sintering flue gas. According to the flue gas release pattern in the sintering process, the flue gas is divided into decarbonized series flue gas and non-decarbonized series flue gas for separate purification, thereby improving the flue gas purification efficiency. Furthermore, the waste heat of the flue gas is fully utilized according to its properties, thereby achieving full utilization of resources.

[0064] 2. The present invention provides a method for the treatment of carbon dioxide capture and synergistic multi-pollutant treatment in sintering flue gas. Based on the characteristics of decarbonized and non-decarbonized flue gas and the influencing factors of denitrification rate, the amount of activated carbon and ammonia required for flue gas purification is calculated, thereby achieving precise control of the amount of activated carbon and ammonia introduced during the purification process. Attached Figure Description

[0065] Figure 1 This is a schematic diagram of the structure of a carbon dioxide capture and multi-pollutant treatment system for sintering flue gas provided by the present invention.

[0066] Figure 2 This is another structural schematic diagram of a carbon dioxide capture and multi-pollutant treatment system for sintering flue gas provided by the present invention.

[0067] Figure 3 This is a diagram showing the material layer distribution during the sintering process.

[0068] Figure 4 The graph shows the changes in SO2 and CO2 concentrations in the sintering flue gas of each air box during the sintering process.

[0069] Figure 5 NO in the sintering flue gas of each air box during the sintering process x Concentration change graph.

[0070] Figure 6 This is a graph showing the temperature changes of the sintering flue gas in each air box during the sintering process.

[0071] Figure 7 The graph shows the concentration changes of SO2 and CO2 in the sintering flue gas of the first 15 wind boxes.

[0072] Figure 8 This is a graph showing the temperature changes of the sintering flue gas in the first 20 wind boxes.

[0073] Figure reference numerals: 1. Sintering machine; 2. Decarbonized series flue gas duct; 3. Non-decarbonized series flue gas duct; 4. Heating device; 5. First desulfurization and denitrification device; 6. Second desulfurization and denitrification device; 7. Cooling device; 8. Carbon dioxide capture device; 9. Chimney; 10. First dust removal device; 11. First fan; 12. Second dust removal device; 13. Second fan; 14. Collector regeneration device; 15. Heat exchange device; L1: First flue gas duct; L2: Second flue gas duct; L3: Third flue gas duct; L4: Fourth flue gas duct; L5: Fifth flue gas duct. Detailed Implementation

[0074] The technical solution of the present invention will be illustrated below with examples. The scope of protection sought by the present invention includes, but is not limited to, the following embodiments.

[0075] A method for treating multiple pollutants in sintering flue gas by capturing carbon dioxide, the method comprising the following steps:

[0076] 1) Based on the running direction of the sintering trolley, the air box below the sintering machine is divided into a front air box and a rear air box. The sintering flue gas in the front air box and the sintering flue gas in the rear air box are treated separately. The sintering flue gas in the front air box is mixed to obtain decarburized flue gas, and the sintering flue gas in the rear air box is mixed to obtain non-decarburized flue gas.

[0077] 2) After the decarbonized flue gas is successively subjected to heating, dust removal, desulfurization and denitrification and cooling treatment, the CO2 in the decarbonized flue gas is then captured by a capture agent and discharged through the chimney.

[0078] 3) The non-decarbonized flue gas is successively treated by dust removal and desulfurization and denitrification before being discharged through a chimney.

[0079] Preferably, the method further includes: 4) thermally regenerating the trapping agent after adsorbing carbon dioxide in step 2) to obtain high-purity carbon dioxide and regenerated trapping agent, and returning the regenerated trapping agent to step 2) for recycling.

[0080] As a preferred option, a portion of the high-temperature flue gas in the rear air box is indirectly heated with the carbon dioxide-adsorbed scavenger to achieve thermal regeneration of the scavenger.

[0081] Preferably, the decarbonized flue gas in step 1) is characterized by: a flue gas temperature of 50–100°C, a CO2 concentration ≥7% (preferably CO2 concentration ≥8%), and an SO2 concentration ≤25 mg / Nm³. 3 (Preferred SO2 concentration ≤ 20 mg / Nm) 3 When the flue gas in the wind box is determined to be decarbonized flue gas, the wind box is assigned to the front wind box; the non-decarbonized flue gas mentioned in step 1) is defined as: when the temperature of the flue gas in the wind box is 50-100℃, or the CO2 concentration is ≤7% (preferably CO2 concentration ≤8%), or the SO2 concentration is ≥25mg / Nm³. 3 (Preferred SO2 concentration ≥ 20 mg / Nm) 3 When the flue gas in the wind box is determined to be non-decarbonized flue gas, the wind box is assigned to the rear wind box.

[0082] Preferably, the CO2 trapping agent in step 2) is an organic amine solution; preferably MDEA, DPMA, MEA or a combination thereof.

[0083] Preferably, the concentration of the organic amine solution is 20–60 wt.%, and the solvent is water, a polar physical solvent, or a combination thereof.

[0084] Preferably, the heating in step 2) involves heating the decarbonized flue gas to 105–150°C, more preferably 110–120°C.

[0085] Preferably, the desulfurization and denitrification in step 2) involves using activated carbon to adsorb and decarbonize small amounts of sulfur dioxide and nitrogen oxides in the flue gas.

[0086] Preferably, the cooling in step 2) is to cool the flue gas after desulfurization and denitrification to 35-60°C, more preferably 40-50°C.

[0087] Preferably, the dust removal described in steps 2) and 3) is an electrostatic precipitator.

[0088] Preferably, the desulfurization and denitrification in step 3) involves using activated carbon to adsorb sulfur dioxide and a small amount of nitrogen oxides in the non-decarbonized flue gas.

[0089] Preferably, the temperature rise in step 2) is a temperature rise after heat exchange between the decarbonized flue gas and the non-decarbonized flue gas; preferably, the temperature of the non-decarbonized flue gas is reduced to 105-150°C after heat exchange, and more preferably to 110-130°C.

[0090] Preferably, the activated carbon control in the desulfurization and denitrification process in steps 2) and 3) is as follows: the amount of activated carbon required for the desulfurization and denitrification process is calculated based on the flue gas denitrification, and the amount of activated carbon required for the flue gas desulfurization and denitrification process is calculated based on the flue gas desulfurization.

[0091] Preferably, in the desulfurization and denitrification process, the concentration of SO2 and NO in the flue gas is considered. x Concentration calculation: the amount of ammonia gas required to be injected during the desulfurization and denitrification process.

[0092] Preferably, the calculation of the required activated carbon addition during the desulfurization and denitrification process based on flue gas denitrification specifically involves:

[0093] The flow rate of the flue gas is measured as Q1, m. 3 Based on the amount of activated carbon required for flue gas denitrification, the required amount of activated carbon to purify the flue gas can be calculated:

[0094]

[0095] In the formula, Y is the denitrification rate of flue gas, %; sv0 is the space velocity of activated carbon adsorbing nitrogen oxides, h. -1 x is a multiple of the space velocity; n is the number of adsorption units in the adsorption tower; the volume of activated carbon in a single adsorption unit in the adsorption tower is v, m. 3 Based on the required denitrification rate, the amount of activated carbon required for purifying flue gas, n*v, is calculated using Equation 1.

[0096] The value of Y is determined by the flue gas purification requirements in the actual process; the value of sv0 ranges from 200 to 500 h. -1 Preferably 250-300h -1 The value of x ranges from 0.5 to 1.2, preferably from 0.6 to 1; n is an integer greater than or equal to 1.

[0097] Preferably, the required circulating amount of activated carbon during the flue gas desulfurization and denitrification process is calculated based on the flue gas desulfurization process, specifically as follows:

[0098] The flow rate of the flue gas is measured as Q1, m. 3 The required circulating amount of activated carbon for flue gas purification can be calculated based on the amount of activated carbon required for flue gas desulfurization.

[0099]

[0100] In the formula, W is the circulating volume of activated carbon in the adsorption tower, in g; C0 is the SO2 concentration in the flue gas at the inlet of the adsorption tower, in mg / Nm³. 3 C1 represents the SO2 concentration in the gas at the outlet of the adsorption tower, and its value ranges from 0 to 35 mg / Nm³. 3 ; s1 represents the adsorption capacity of activated carbon for SO2, in mg / g.

[0101] Preferably, the amount of ammonia gas required for the desulfurization and denitrification process is calculated based on the SO2 and NOx concentrations in the flue gas, specifically as follows:

[0102]

[0103] In the formula, C3 represents the amount of ammonia required for desulfurization and denitrification, in mg / Nm³. 3 C0 represents the SO2 concentration at the inlet of the adsorption tower; C2 represents the NO concentration at the inlet of the adsorption tower. x concentration.

[0104] Preferably, the thermal regeneration treatment of the trapping agent in step 4) is as follows: the trapping agent is heated to 110-130°C and regenerated for 0.3-1 hour to obtain a regenerated trapping agent.

[0105] According to a second embodiment of the present invention, a treatment system for capturing carbon dioxide and co-treating multiple pollutants in sintering flue gas is provided.

[0106] A system for the coordinated treatment of carbon dioxide capture and multiple pollutants in sintering flue gas is disclosed. The system includes a sintering machine 1, a decarbonization series flue gas duct 2, a non-decarbonization series flue gas duct 3, a heating device 4, a first desulfurization and denitrification device 5, a second desulfurization and denitrification device 6, a cooling device 7, and a carbon dioxide capture device 8. The bottom air box of the sintering machine 1 is divided into a front air box and a rear air box, with the front air box connected to the decarbonization series flue gas duct 2 and the rear air box connected to the non-decarbonization series flue gas duct 3. The flue gas outlet of the decarbonization series flue gas duct 2 is connected to the flue gas inlet of the heating device 4 via a first flue gas pipe L1. The flue gas outlet of the heating device 4 is connected to the flue gas inlet of the first desulfurization and denitrification device 5 via a second flue gas pipe L2. The flue gas inlet of the first desulfurization and denitrification device 5 is connected to the flue gas inlet of the cooling device 7 via a third flue gas pipe L3. The flue gas outlet of the cooling device 7 is connected to the flue gas inlet of the carbon dioxide capture device 8 via a fourth flue gas pipe L4. The non-decarbonized flue gas duct 3 is connected to the second desulfurization and denitrification device 6 via the fifth flue gas duct L4. The flue gas outlet of the second desulfurization and denitrification device 6 is connected to the chimney 9.

[0107] Preferably, the front air box is the air box that is 1 / 4 to 3 / 4 of the length closest to the head of the sintering machine, and the remaining air boxes are the rear air boxes.

[0108] Preferably, the system also includes a central air box. The central air box includes a portion of the air box at the rear end of the front air box and / or a portion of the air box at the front end of the rear air box. Each of the central air boxes is connected to the decarbonized flue gas duct 2 and the non-decarbonized flue gas duct 3 via a three-way branch pipe, and a switching valve is provided at the three-way branch pipe.

[0109] Preferably, the first flue gas duct L1 is equipped with a first dust removal device 10 and a first fan 11.

[0110] Preferably, the fifth flue gas duct L4 is equipped with a second dust removal device 12 and a second fan 13.

[0111] Preferably, the decarbonized flue gas duct 2 and / or the non-decarbonized flue gas duct 3 are further equipped with a temperature detection device and a flue gas composition detection device.

[0112] Preferably, the system further includes a trap regeneration device 14. The trap outlet of the carbon dioxide capture device 8 is connected to the trap inlet of the trap regeneration device 14. The flue gas outlet of the trap regeneration device 14 is connected to the chimney 9. Preferably, the trap outlet of the trap regeneration device 14 is connected to the trap inlet of the carbon dioxide capture device 8.

[0113] Preferably, the system further includes a heat exchange device 15, which is connected to a portion of the tail section air box. The first flue gas duct L1 passes through the heat exchange device 15. Preferably, the flue gas outlet of the heat exchange device 15 is connected to the heat source inlet of the trap regeneration device 14. The heat source outlet of the trap regeneration device 14 is connected to the second desulfurization and denitrification device 6.

[0114] Example 1

[0115] A system for the coordinated treatment of carbon dioxide capture and multiple pollutants in sintering flue gas is disclosed. The system includes a sintering machine 1, a decarbonization series flue gas duct 2, a non-decarbonization series flue gas duct 3, a heating device 4, a first desulfurization and denitrification device 5, a second desulfurization and denitrification device 6, a cooling device 7, and a carbon dioxide capture device 8. The bottom air box of the sintering machine 1 is divided into a front air box and a rear air box, with the front air box connected to the decarbonization series flue gas duct 2 and the rear air box connected to the non-decarbonization series flue gas duct 3. The flue gas outlet of the decarbonization series flue gas duct 2 is connected to the flue gas inlet of the heating device 4 via a first flue gas pipe L1. The flue gas outlet of the heating device 4 is connected to the flue gas inlet of the first desulfurization and denitrification device 5 via a second flue gas pipe L2. The flue gas inlet of the first desulfurization and denitrification device 5 is connected to the flue gas inlet of the cooling device 7 via a third flue gas pipe L3. The flue gas outlet of the cooling device 7 is connected to the flue gas inlet of the carbon dioxide capture device 8 via a fourth flue gas pipe L4. The non-decarbonized flue gas duct 3 is connected to the second desulfurization and denitrification device 6 via the fifth flue gas duct L4. The flue gas outlet of the second desulfurization and denitrification device 6 is connected to the chimney 9.

[0116] The front air box is the air box that is 1 / 4 to 3 / 4 of the length closest to the head of the sintering machine, and the remaining air boxes are the rear air boxes.

[0117] Example 2

[0118] The system repeats Example 1, except that it also includes a central air box. The central air box includes five air boxes at the rear end of the front air box and three air boxes at the front end of the rear air box. Each of the central air boxes is connected to the decarbonized flue gas duct 2 and the non-decarbonized flue gas duct 3 via a three-way branch pipe, and a switching valve is provided at the three-way branch pipe.

[0119] Example 3

[0120] The same as Embodiment 2 is repeated, except that the first flue gas duct L1 is equipped with a first dust removal device 10 and a first fan 11.

[0121] The fifth flue gas duct L4 is equipped with a second dust removal device 12 and a second fan 13.

[0122] Example 4

[0123] Example 3 is repeated, except that the decarbonized flue gas duct 2 and the non-decarbonized flue gas duct 3 are also equipped with a temperature detection device and a flue gas composition detection device.

[0124] Example 5

[0125] The system repeats Example 4, except that it also includes a trap regeneration device 14. The trap outlet of the carbon dioxide capture device 8 is connected to the trap inlet of the trap regeneration device 14. The flue gas outlet of the trap regeneration device 14 is connected to the chimney 9. The trap outlet of the trap regeneration device 14 is connected to the trap inlet of the carbon dioxide capture device 8.

[0126] Example 6

[0127] The system repeats Embodiment 5, except that it further includes a heat exchanger 15, which is connected to a portion of the tail section air box. The first flue gas duct L1 passes through the heat exchanger 15. Preferably, the flue gas outlet of the heat exchanger 15 is connected to the heat source inlet of the trap regeneration device 14. The heat source outlet of the trap regeneration device 14 is connected to the second desulfurization and denitrification device 6.

[0128] Application Example 1

[0129] A method for treating multiple pollutants in sintering flue gas by capturing carbon dioxide, the method comprising:

[0130] 1) Based on the movement direction of the sintering trolley, detect the composition of the flue gas in the air box, divide the air box below the sintering machine into front air boxes No. 1 to 15 and rear air boxes No. 16 to 28, and pass the sintering flue gas in the front air box into the decarburization series flue gas duct, and pass the sintering flue gas in the rear air box into the non-decarburization series flue gas duct.

[0131] 2) The decarbonization series flue gas is heated to 110℃, and after passing through the electrostatic precipitator, it is fed into the first desulfurization and denitrification device. After the desulfurization and denitrification are completed, the temperature is reduced to 45℃, and then the flue gas is fed into the carbon dioxide capture device. Organic amine solution is used to capture carbon dioxide in the flue gas, and the clean flue gas is discharged through the chimney.

[0132] Among them, the flow rate of the decarbonization series flue gas was measured to be Q1 = 250000 m³. 3 The SO2 concentration in the flue gas was 37 mg / Nm³. 3 The CO2 content is 12%, NO x The concentration was 517 mg / Nm 3 .

[0133] Calculate the amount of activated carbon to be added in the first desulfurization and denitrification unit:

[0134]

[0135] In the formula, Y is the denitrification rate of the decarbonized flue gas, %; sv0 is the space velocity of activated carbon adsorbing nitrogen oxides, taken as 300 h⁻¹. -1x is a multiple of the space velocity, with a value of 0.9; n is the number of adsorption units in the first desulfurization and denitrification unit; the activated carbon loading volume of a single adsorption unit in the first desulfurization and denitrification unit is v, m 3 ;

[0136] Among them, NO in decarbonized flue gas x The concentration was 517 mg / Nm 3 To ensure that NO in flue gas emissions x <50mg / Nm 3 If Y is greater than 90.3%, then Y should be greater than 90.3%; when Y is 90.4%, then n*v = 3826.5m is calculated. 3 If the number of adsorption units in the first desulfurization and denitrification unit is n=6, then the loading volume of activated carbon in a single adsorption unit is v=637m³. 3 .

[0137] Activated carbon has high denitrification efficiency and low SO2 content in the decarbonized flue gas. The activated carbon circulation rate only needs to consider SO2 adsorption.

[0138] Calculate the circulating volume of activated carbon in the first desulfurization and denitrification unit:

[0139]

[0140] In the formula, W1 is the circulation rate of activated carbon in the first desulfurization and denitrification unit, in tons (t); C0 is the SO2 concentration at the flue gas inlet of the first desulfurization and denitrification unit, taken as 1173 mg / Nm³. 3 C1 represents the SO2 concentration at the flue gas outlet of the first desulfurization and denitrification unit, and its value is 5 mg / Nm³. 3 ; s1 is the adsorption capacity of activated carbon for SO2, with a value of 24 mg / g;

[0141] In addition, the carbon dioxide capture agent in the device is MDEA. The concentration of MDEA is 40 wt%, and the solvent is water.

[0142] In the decarbonization system, under the condition of adding NH3, SO2 and NOx will react with NH3 simultaneously.

[0143] The ammonia concentration required for desulfurization and denitrification of decarbonized flue gas:

[0144]

[0145] In the formula, C3 represents the amount of ammonia required for decarbonization, desulfurization, and denitrification in the decarbonization series, expressed in mg / Nm³. 3 C0 is the SO2 concentration at the flue gas inlet of the first desulfurization and denitrification unit; C2 is the NOx concentration at the flue gas inlet of the first desulfurization and denitrification unit.

[0146] The first desulfurization and denitrification unit uses 6 adsorption units, with an activated carbon loading volume of v = 637 m³ in each unit. 3 The circulation rate of the first desulfurization and denitrification unit is controlled at 0.33t per unit time, and the ammonia required for the decarbonization and desulfurization / nitrification series is 177.48 mg / Nm³. 3 .

[0147] 3) After the non-decarbonized flue gas passes through the electrostatic precipitator, it is fed into the second desulfurization and denitrification unit. The clean flue gas after desulfurization and denitrification is discharged through the chimney.

[0148] Among them, the flow rate of the non-decarbonized series flue gas was measured to be Q2 = 650000 m³. 3 The SO2 concentration in the flue gas was 1173 mg / Nm³. 3 NO x Concentration of 95 mg / Nm 3 .

[0149] The amount of activated carbon required for non-decarbonization series flue gas denitrification is:

[0150]

[0151] In the formula, Y' represents the denitrification rate of the non-decarbonized flue gas series, %, sv0 ’ The space velocity for activated carbon adsorbing nitrogen oxides is taken as 300 h⁻¹. -1 x is the airspeed sv0 ’ Multiples of n, with a value of 0.6; ’ v represents the number of adsorption units within the second desulfurization and denitrification unit. ’ This refers to the volume of activated carbon packed in a single adsorption unit within the second desulfurization and denitrification unit.

[0152] Among them, due to the NO in non-decarbonized flue gas x The concentration was low, at 95 mg / Nm³. 3 Y ’ When the value of is 80%, the calculated n ’ *v ’ =4333m 3 The number n of adsorption units set in the second desulfurization and denitrification unit ’ =6, then the packing volume v of the activated carbon in a single adsorption unit can be obtained. ’ =722m 3 .

[0153] Calculate the circulating volume of activated carbon in the second desulfurization and denitrification unit:

[0154]

[0155] In the formula, W2 is the circulation rate of activated carbon in the second desulfurization and denitrification unit, in tons (t); C0 is the SO2 concentration at the flue gas inlet of the second desulfurization and denitrification unit, taken as 1173 mg / Nm³. 3 C1 represents the SO2 concentration at the flue gas outlet of the second desulfurization and denitrification unit, and its value is 35 mg / Nm³. 3 ; s1 is the adsorption capacity of activated carbon for SO2, with a value of 24 mg / g; at the same time, in the non-decarbonization system, under the condition of adding NH3, SO2 and NOx will react with NH3 simultaneously.

[0156] The ammonia concentration required for denitrification of non-decarbonized flue gas:

[0157]

[0158] In the formula, C3 represents the amount of ammonia required for denitrification in the non-decarbonization series, in mg / Nm³. 3 C0 represents the SO2 concentration at the inlet of the second desulfurization and denitrification unit; C2 represents the NOx concentration at the inlet of the second desulfurization and denitrification unit.

[0159] The second desulfurization and denitrification unit uses 6 adsorption units, with an activated carbon loading volume of v = 722 m³ in each unit. 3 The circulation rate of the first desulfurization and denitrification unit is controlled at 30.82t per unit time, and the ammonia required for the decarbonization and desulfurization / nitrification series is 171.6 mg / Nm³. 3 .

[0160] 4) The carbon dioxide-absorbing agent from step 2) is regenerated by heating at 120°C for 0.6 hours, and the regenerated agent is recycled back to the carbon dioxide capture device to obtain CO2, which is then emitted through the chimney. The purity of the obtained CO2 is 99.3 wt%.

Claims

1. A method for treating sintering flue gas by capturing carbon dioxide and synergistically treating multiple pollutants, characterized in that: The method includes the following steps: 1) Based on the running direction of the sintering trolley, the air box under the sintering machine is divided into a front air box and a rear air box. The sintering flue gas in the front air box and the sintering flue gas in the rear air box are treated separately. The sintering flue gas in the front air box is mixed to obtain decarburized flue gas, and the sintering flue gas in the rear air box is mixed to obtain non-decarburized flue gas. 2) After the decarbonized flue gas is successively subjected to heating, dust removal, desulfurization and denitrification and cooling treatment, the CO2 in the decarbonized flue gas is then captured by a capture agent and discharged through the chimney. 3) The non-decarbonized flue gas is successively treated by dust removal and desulfurization and denitrification before being discharged through a chimney; Specifically, the activated carbon control in the desulfurization and denitrification processes described in steps 2) and 3) is as follows: the amount of activated carbon required for the desulfurization and denitrification process is calculated based on the flue gas denitrification process, specifically by measuring the flue gas flow rate as Q1, m. 3 Based on the amount of activated carbon required for flue gas denitrification, the required amount of activated carbon to purify the flue gas can be calculated: ... (Equation 1); where Y is the denitrification rate of flue gas, %; sv0 is the space velocity of activated carbon adsorbing nitrogen oxides, h. -1 x is a multiple of the space velocity; n is the number of adsorption units in the adsorption tower; the volume of activated carbon in a single adsorption unit in the adsorption tower is v, m. 3 Based on the required denitrification rate, the amount of activated carbon required for flue gas purification, n*v, is calculated using Equation 1; where the value of Y is determined by the actual flue gas purification requirements in the process; and the value of sv0 ranges from 200 to 500 h. -1 The value of x ranges from 0.5 to 1.2; n is an integer greater than or equal to 1. The required circulating amount of activated carbon during the flue gas desulfurization and denitrification process is calculated based on the flue gas desulfurization process; specifically, the flue gas flow rate is measured as Q1, m. 3 The required circulating amount of activated carbon for flue gas purification can be calculated based on the amount of activated carbon required for flue gas desulfurization. ... (Equation 2); where W is the circulation rate of activated carbon in the adsorption tower, in g; C0 is the SO2 concentration in the flue gas at the inlet of the adsorption tower, in mg / Nm³. 3 C1 represents the SO2 concentration in the gas at the outlet of the adsorption tower, and its value ranges from 0 to 35 mg / Nm³. 3 ; s1 represents the adsorption capacity of activated carbon for SO2, in mg / g.

2. The method according to claim 1, characterized in that: The value of sv0 ranges from 250 to 300h. -1 The value of x ranges from 0.6 to 1.

3. The method according to claim 1, characterized in that: The method further includes: 4) thermally regenerating the trapping agent after adsorbing carbon dioxide in step 2) to obtain high-purity carbon dioxide and regenerated trapping agent, and returning the regenerated trapping agent to step 2) for recycling.

4. The method according to claim 3, characterized in that: Indirect heat exchange is performed between some of the high-temperature flue gas in the rear air box and the scavenging agent after adsorbing carbon dioxide to achieve thermal regeneration of the scavenging agent.

5. The method according to claim 1, characterized in that: The decarbonization series of flue gas mentioned in step 1) is as follows: when the temperature of the flue gas in the blower box is 50~100℃, the CO2 concentration is ≥7%, and the SO2 concentration is ≤25mg / Nm³. 3 When the flue gas in the wind box is determined to be decarbonized flue gas, the wind box is assigned to the front wind box; the non-decarbonized flue gas mentioned in step 1) is defined as: when the temperature of the flue gas in the wind box is 50~100℃, or the CO2 concentration is ≤7%, or the SO2 concentration is ≥25mg / Nm³. 3 At that time, the flue gas in the wind box was determined to be non-decarbonized flue gas, and the wind box was assigned to the rear wind box.

6. The method according to claim 1, characterized in that: The decarbonization series flue gas mentioned in step 1) is as follows: when the temperature of the flue gas in the blower box is 50~100℃, the CO2 concentration is ≥8%, and the SO2 concentration is ≤20mg / Nm³. 3 When the flue gas in the wind box is determined to be decarbonized flue gas, the wind box is assigned to the front wind box; the non-decarbonized flue gas mentioned in step 1) is defined as: when the temperature of the flue gas in the wind box is 50~100℃, or the CO2 concentration is ≤8%, or the SO2 concentration is ≥20mg / Nm³. 3 At that time, the flue gas in the wind box was determined to be non-decarbonized flue gas, and the wind box was assigned to the rear wind box.

7. The method according to claim 1, characterized in that: The CO2 trapping agent mentioned in step 2) is an organic amine solution.

8. The method according to claim 7, characterized in that: The CO2 trapping agent mentioned in step 2) is MDEA, DPMA, MEA, or a combination thereof.

9. The method according to claim 7, characterized in that: The concentration of the organic amine solution is 20~60 wt.%; the solvent is water, a polar physical solvent, or a combination thereof.

10. The method according to claim 1, characterized in that: Step 2) involves heating the decarbonized flue gas to 105-150°C.

11. The method according to claim 10, characterized in that: Step 2) involves heating the decarbonized flue gas to 110-120°C.

12. The method according to claim 1, characterized in that: Step 2) refers to cooling the flue gas after desulfurization and denitrification to 35~60℃.

13. The method according to claim 12, characterized in that: Step 2) refers to cooling the flue gas after desulfurization and denitrification to 40~50℃.

14. The method according to claim 1, characterized in that: The dust removal described in steps 2) and 3) is electrostatic precipitator.

15. The method according to claim 1, characterized in that: The temperature increase mentioned in step 2) is the temperature increase after heat exchange between the decarbonized flue gas and the non-decarbonized flue gas.

16. The method according to claim 15, characterized in that: The non-decarburized series cools down to 105~150℃ after heat exchange.

17. The method according to claim 16, characterized in that: The non-decarburized series cools down to 110~130℃ after heat exchange.

18. The method according to any one of claims 1-17, characterized in that: During the desulfurization and denitrification process, based on the SO2 concentration and NO concentration in the flue gas x Concentration calculation: the amount of ammonia gas required to be injected during the desulfurization and denitrification process.

19. The method according to claim 18, characterized in that: The amount of ammonia gas required for the desulfurization and denitrification process is calculated based on the SO2 and NOx concentrations in the flue gas. ... (Equation 3) In the formula, C3 represents the amount of ammonia required for desulfurization and denitrification, in mg / Nm³. 3 C0 represents the SO2 concentration at the inlet of the adsorption tower; C2 represents the NO concentration at the inlet of the adsorption tower. x concentration.

20. The method according to claim 3, characterized in that: Step 4) involves thermal regeneration of the trapping agent by heating it to 110-130°C and regenerating it for 0.3-1 hour to obtain a regenerated trapping agent.

21. A system for which the method of any one of claims 1-20 is applied, characterized in that: The system includes a sintering machine (1), a decarbonized flue gas duct (2), a non-decarbonized flue gas duct (3), a heating device (4), a first desulfurization and denitrification device (5), a second desulfurization and denitrification device (6), a cooling device (7), and a carbon dioxide capture device (8); the bottom air box of the sintering machine (1) is divided into a front air box and a rear air box, wherein the front air box is connected to the decarbonized flue gas duct (2), and the rear air box is connected to the non-decarbonized flue gas duct (3); the flue gas outlet of the decarbonized flue gas duct (2) is connected to the flue gas inlet of the heating device (4) through the first flue gas pipe (L1); heating The flue gas outlet of device (4) is connected to the flue gas inlet of the first desulfurization and denitrification device (5) through the second flue gas pipe (L2); the flue gas inlet of the first desulfurization and denitrification device (5) is connected to the flue gas inlet of the cooling device (7) through the third flue gas pipe (L3); the flue gas outlet of the cooling device (7) is connected to the flue gas inlet of the carbon dioxide capture device (8) through the fourth flue gas pipe (L4); the non-decarbonization series flue gas duct (3) is connected to the second desulfurization and denitrification device (6) through the fifth flue gas pipe (L5); the flue gas outlet of the second desulfurization and denitrification device (6) is connected to the chimney (9).

22. The system according to claim 21, characterized in that: The front air box is the air box that is 1 / 4 to 3 / 4 of the length closest to the head of the sintering machine, and the remaining air boxes are the rear air boxes.

23. The system according to claim 22, characterized in that: The system also includes a central air box; the central air box includes a portion of the air box at the rear end of the front air box and / or a portion of the air box at the front end of the rear air box; each of the central air boxes is connected to the decarbonized flue gas duct (2) and the non-decarbonized flue gas duct (3) through a three-way branch pipe, and a switching valve is provided at the three-way branch pipe.

24. The system according to claim 21, characterized in that: The second flue gas duct (L2) is equipped with a first dust removal device (10) and a first fan (11); and / or The fifth flue gas duct (L5) is equipped with a second dust removal device (12) and a second fan (13); and / or Temperature detection devices and flue gas composition detection devices are also installed in the decarbonized series flue gas duct (2) and / or non-decarbonized series flue gas duct (3).

25. The system according to any one of claims 21-24, characterized in that: The system also includes a trap regeneration device (14); the trap outlet of the carbon dioxide trap (8) is connected to the trap inlet of the trap regeneration device (14); the flue gas outlet of the trap regeneration device (14) is connected to the chimney (9).

26. The system according to claim 25, characterized in that: The trap outlet of the trap regeneration device (14) is connected to the trap inlet of the carbon dioxide trap (8).

27. The system according to claim 26, characterized in that: The system also includes a heat exchange device (15) connected to a portion of the tail section air box; the first flue gas duct (L1) passes through the heat exchange device (15).

28. The system according to claim 27, characterized in that: The flue gas outlet of the heat exchange device (15) is connected to the heat source inlet of the trap regeneration device (14); the heat source outlet of the trap regeneration device (14) is connected to the second desulfurization and denitrification device (6).

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