Method for synergistically capturing carbon dioxide in sintering flue gas and treating multiple pollutants

Abstract

A method for synergistically capturing carbon dioxide in sintering flue gas and treating multiple pollutants. The method comprises: 1) dividing an air bellow into a front air bellow and a rear air bellow along the moving direction of a sinter pallet car, and separately treating sintering flue gas in the front air bellow and sintering flue gas in the rear air bellow; 2) sequentially performing heating, dust removal, desulfurization and denitrification, and cooling treatments on decarburized-series flue gas, capturing CO2 in the decarburized-series flue gas by using a capturing agent, and then discharging same via a chimney; and 3) subjecting non-decarburized-series flue gas to dust removal, and desulfurization and denitrification treatments in sequence, and then discharging same via the chimney. In the present invention, on the basis of the release rule of flue gas during sintering, the flue gas is divided into decarburized-series flue gas and non-decarburized-series flue gas for separate purification, thereby improving the purification efficiency of the flue gas; and waste heat of the flue gas is fully utilized on the basis of the performance of the flue gas, thereby achieving the full utilization of resources.

Description

A method for capturing carbon dioxide and coordinating multiple pollutants in sintering flue gas Technical Field

[0001] The present invention relates to a method for treating multiple pollutants in sintering flue gas, and in particular to a method for treating multiple pollutants in sintering flue gas by capturing carbon dioxide and coordinating the capture of carbon dioxide, belonging to the field of sintering flue gas treatment. Background Art

[0002] Carbon peak and carbon neutrality have now become a broad global consensus. my country attaches great importance to the promotion and implementation of the "dual carbon" goals and tasks. It has repeatedly emphasized and reiterated the importance and necessity of doing a good job in carbon peak and carbon neutrality at important meetings, and introduced implementation measures. Low-carbon policies will gradually shift from relative constraints to absolute constraints.

[0003] Among them, CO2 capture, conversion, and utilization are feasible technical options for low-carbon transformation in industries such as steel and cement that are difficult to reduce emissions. Currently, the main carbon dioxide capture technologies in the steel industry include waste heat and waste energy recovery technology. The use of recovery technology reduces fossil energy consumption and can effectively reduce carbon dioxide emissions; the second is CCUS technology, which is one of the key technologies for addressing global climate change. The main methods for capturing carbon dioxide are pre-combustion capture, oxygen-enriched combustion, and post-combustion capture. Among them, post-combustion capture technology has the fastest industrialization process and is already in the industrial application stage, while pre-combustion capture and oxygen-enriched combustion capture technologies are still in the industrial demonstration and pilot demonstration stages, respectively. Post-combustion capture technology is to separate carbon dioxide from flue gas in the capture system to form high-concentration carbon dioxide, which is then utilized.

[0004] The most mature post-combustion capture system is the cyclic adsorption system, which uses liquid-phase adsorption of organic amines to selectively remove soluble organic amine components from the gas phase through chemical reactions. Organic amine systems primarily consist of an absorption unit, a desorption unit (regeneration unit), energy exchange devices (such as a lean-rich liquid heat exchanger, a lean liquid cooler, a condenser, and a condenser reflux unit), system power units (such as a lean liquid pump, a secondary liquid pump, a reflux pump, a booster pump, and a fan), and auxiliary equipment (such as a flue gas pretreatment unit, a liquid replenishment unit, and a filter). However, the adsorption temperature of the typical primary amine solvent, monoethanolamine (MEA), ranges from 40-70°C, while regeneration requires heating to approximately 120°C. The regeneration energy consumption (4.1 Gt / t CO2) accounts for over 60% of the total energy consumption of the decarbonization system and 50-60% of the operating costs of the CO2 capture process. The high energy consumption of the organic amine solvent regeneration process has seriously hindered the industrial application of this technology.

[0005] At present, the steel industry mainly adopts post-combustion capture, and the commonly used technologies include physical adsorption, chemical absorption and membrane separation. Through post-combustion carbon capture technology, the carbon dioxide emitted by each process can be effectively captured. However, the sintering flue gas volume is large, and the exhaust gas contains complex components, including SO2, NO x Conventional pollutants such as sintering flue gas, dust, and gases such as CO2, H2O, and N2 have a serious impact on the environment. At the same time, due to the high emission temperature of sintering flue gas, the current conventional CO2 capture technology cannot be effectively used. Therefore, a feasible, low-cost and efficient sintering flue gas CO2 capture process is needed for the complex components in sintering flue gas, as well as a method for treating other pollutants. Summary of the Invention

[0006] In view of the problem that the CO2 capture technology in the existing technology cannot be used well and there is a lack of comprehensive treatment methods for carbon dioxide, sulfides and nitrogen oxides in flue gas, the present invention proposes a method for capturing carbon dioxide in sintering flue gas and coordinating multiple pollutants for treatment. According to the release law of sintering flue gas, the sintering flue gas is divided into a decarbonization series flue gas and a non-decarbonization series flue gas, and different purification processes are set according to the concentration of pollutants in the flue gas to accurately control the introduction amount of activated carbon and ammonia.

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

[0008] 1) According to the running direction of the sintering trolley, the bellows under the sintering machine are divided into front bellows and rear bellows. The sintering flue gas in the front bellows and the sintering flue gas in the rear bellows are treated separately. The sintering flue gas in the front bellows is mixed to obtain the decarburized series flue gas, and the sintering flue gas in the rear bellows is mixed to obtain the non-decarburized series flue gas.

[0009] 2) After the decarbonization series flue gas undergoes heating, dust removal, desulfurization and denitrification, and cooling treatments, the CO2 in the decarbonization series flue gas is captured by a capture agent and then discharged through the chimney;

[0010] 3) The non-decarbonized flue gas is sequentially treated with dust removal, desulfurization and denitrification before being discharged through the chimney.

[0011] Preferably, the method further comprises: 4) subjecting the capture agent after adsorbing carbon dioxide in step 2) to thermal regeneration to obtain high-purity carbon dioxide and regenerated capture agent, and returning the regenerated capture agent to step 2) for recycling.

[0012] Preferably, part of the high-temperature flue gas in the rear wind box is subjected to indirect heat exchange with the capture agent after adsorbing carbon dioxide to achieve thermal regeneration of the capture agent.

[0013] Preferably, the decarbonized flue gas in step 1) is: when the temperature of the flue gas in the wind box is 50-100°C, the CO2 concentration is ≥7% (preferably the CO2 concentration is ≥8%), and the SO2 concentration is ≤25mg / Nm 3 (Preferably SO2 concentration ≤ 20 mg / Nm 3 ), the flue gas in the windbox is determined to be a decarburized series flue gas, and the windbox is divided into the front windbox; the non-decarburized series flue gas in step 1) is: when the temperature of the flue gas in the windbox is 50-100°C, or the CO2 concentration is ≤7% (preferably the CO2 concentration is ≤8%), or the SO2 concentration is ≥25mg / Nm 3 (Preferably SO2 concentration ≥ 20mg / Nm 3 ), the flue gas in the bellows is determined to be non-decarburization series flue gas, and the bellows is divided into the rear bellows.

[0014] Preferably, the CO2 capture 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) is to heat the decarburized flue gas to 105-150°C, preferably 110-120°C.

[0017] Preferably, the desulfurization and denitrification in step 2) is carried out by using activated carbon to adsorb a small amount of sulfur dioxide and nitrogen oxides in the decarbonization series flue gas.

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

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

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

[0021] Preferably, the heating in step 2) is performed after heat exchange between the decarburized series flue gas and the non-decarburized series flue gas; preferably, the non-decarburized series flue gas is cooled to 105-150°C, preferably 110-130°C after heat exchange.

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

[0023] As a preference, in the desulfurization and denitrification process, according to the concentration of SO2 and NO in the flue gas, x The concentration is used to calculate the amount of ammonia required to be injected during the desulfurization and denitrification process.

[0024] Preferably, the amount of activated carbon required for the desulfurization and denitrification process is calculated based on the flue gas denitrification, specifically:

[0025] The flow rate of flue gas is measured as Q1, m 3 According to the amount of activated carbon required for flue gas denitrification, the amount of activated carbon required for flue gas purification can be obtained:

[0026] ... (Formula 1)

[0027] Where, Y is the denitrification rate of flue gas, %; sv0 is the space velocity of activated carbon adsorbing nitrogen oxides, h -1 ; x is the multiple of the air velocity; n is the number of adsorption units in the adsorption tower; the filling volume of activated carbon in a single adsorption unit in the adsorption tower is v, m 3 According to the denitrification rate, the amount of activated carbon required to purify the flue gas is calculated by formula 1. .

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

[0029] Preferably, the circulation amount of activated carbon required in the flue gas desulfurization and denitrification process is calculated based on the flue gas desulfurization, specifically:

[0030] The flow rate of flue gas is measured as Q1, m 3 According to the amount of activated carbon required for flue gas desulfurization, the circulation amount of activated carbon required for flue gas purification can be obtained:

[0031] ... (Formula 2)

[0032] Where W is the circulation amount of activated carbon in the adsorption tower, g; C0 is the SO2 concentration in the flue gas at the inlet of the adsorption tower, mg / Nm 3 ; C1 is the SO2 concentration in the gas at the outlet of the adsorption tower, and the value of C1 is 0~35 mg / Nm 3 ; s1 is the adsorption capacity of activated carbon for SO2, mg / g.

[0033] Preferably, the amount of ammonia gas required to be injected during the desulfurization and denitrification process is calculated based on the SO2 concentration and NOx concentration in the flue gas, specifically:

[0034] ... (Formula 3)

[0035] Where C3 is the amount of ammonia required for desulfurization and denitrification, mg / Nm 3 ; C0 is the SO2 concentration at the adsorption tower entrance; C2 is the NO x concentration.

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

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

[0038] A system for capturing carbon dioxide from sintering flue gas and coordinating multiple pollutants for treatment is disclosed. The system includes a sintering machine, a decarbonization flue gas duct, a non-decarbonization 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 bellows of the sintering machine are divided into a front bellows and a rear bellows, wherein the front bellows is connected to the decarbonization flue gas duct, and the rear bellows is connected to the non-decarbonization flue gas duct. The flue gas outlet of the decarbonization 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 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 windboxes are the 1 / 4 to 3 / 4 of the windboxes near the sintering machine head, and the remaining windboxes are the rear windboxes. The front windboxes, which are the 1 / 4 to 3 / 4 of the windboxes near the sintering machine head, refer to the 1 / 4 to 3 / 4 of the windboxes near the sintering machine head when the total number of windboxes is 27 to 32. If the total number of windboxes is large, the front and rear windboxes are further divided according to the current operating conditions by detecting the flue gas composition in the windboxes.

[0040] Preferably, the system further comprises a central wind box; the central wind box comprises a portion of the wind box at the rear end of the front wind box and / or a portion of the wind box at the front end of the rear wind box. Each of the central wind boxes is connected to the decarburization series flue gas duct and the non-decarburization series 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 provided with a first dust removal device and a first fan.

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

[0043] Preferably, a temperature detection device and a flue gas composition detection device are further provided in the decarburization series flue gas duct and / or the non-decarburization series flue gas duct.

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

[0045] Preferably, the system further comprises a heat exchanger connected to a portion of the tail windbox. The first flue gas duct is disposed through the heat exchanger. Preferably, the flue gas outlet of the heat exchanger is connected to the heat source inlet of the scavenging agent regeneration device. The heat source outlet of the scavenging agent regeneration device is connected to the second desulfurization and denitrification device.

[0046] In the present invention, sintering is a process based on the principles of the sintering process. Various iron-containing raw materials are mixed with a specific amount of fuel, solvent, return ore, and water as required, uniformly mixed, pelletized, and spread onto a sintering machine. Under the influence of the draft from the lower bellows, ignition occurs at the surface of the material bed, and a high-temperature roasting reaction proceeds from top to bottom. Because the sintering process begins at the surface of the material bed and proceeds gradually downward, distinct stratification occurs along the height of the material bed during sintering. Based on the temperature levels and physical and chemical composition of each layer, the sintering material bed can be divided into five zones (as shown in Figure 3): from top to bottom, the sintering zone, combustion zone, drying and preheating zone, over-wetting zone, and raw material zone.

[0047] In the present invention, the flue gas release patterns during the sintering process were studied and summarized (as shown in Figures 4-8). When the total number of bellows was 28, the CO2 concentration was higher in the branch pipes of bellows No. 1 to 17, mainly between 8% and 14%. After bellows No. 17, the CO2 concentration gradually decreased to 0. From the perspective of the sintering process, the CO2 in the early stage originated from the fuel during the iron ore sintering process. The significant decrease in CO2 content in the later stage was due to the completion of the sintering end point and the significant consumption of fuel. In addition, the SO2 concentration was very low in the branch pipes of bellows No. 0 to 15. The SO2 concentration in bellows No. 15 to 28 went from a slow increase to a sharp release and then a slow decrease. This is mainly because the presence of the sintering over-wet zone absorbs a large amount of SO2 generated in the ore. When the over-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-mentioned SO2 and CO2 distribution patterns, the flue gas in the bellows is divided into two series: a decarburization series and a non-decarburization series. At the same time, the temperature change pattern and the release pattern of nitrogen oxides during the sintering process were detected. It can be seen that when the flue gas temperature of the decarburization series is between 50 and 100 degrees Celsius, the concentration of nitrogen oxides in the flue gas of the decarburization series is higher, while the concentration of nitrogen oxides in the flue gas of the non-decarburization series is greatly reduced. The conditions for the intermediate decarburization series flue gas are: the flue gas temperature is 50-100 degrees Celsius, the CO2 concentration is ≥8%, and the SO2 concentration is ≤20mg / Nm 3 , and the decarbonization series flue gas volume accounts for about 30% of the total flue gas volume.

[0048] In the present invention, the decarburization series flue gas and the non-decarburization series flue gas are treated separately according to the emission pattern of the flue gas during the sintering process. Since the temperature and SO2 concentration of the decarburization series flue gas are relatively low, and the activated carbon has a high adsorption efficiency for SO2, there is no need for additional desulfurization treatment, and the amount of ammonia injection required for the decarburization series flue gas can be directly calculated. In addition, since the NO2 concentration of the non-decarburization series flue gas is relatively low, the amount of ammonia injection required for the decarburization series flue gas can be directly calculated. x Low concentration, average concentration is 80~100mg / Nm 3 According to the existing nitrogen oxide emission standards, the denitrification efficiency can reach 50%. Calculate the amount of activated carbon and ammonia injection required for the non-decarbonization series flue gas.

[0049] In the present invention, it is found that the organic amine solution has strict conditions for the adsorption of CO2. In a low-sulfur, low-temperature, low-dust and high-CO2 environment, the CO2 capture efficiency will increase significantly. Therefore, the decarbonization series flue gas is heated to the denitrification temperature and then dusted and enters deep desulfurization and denitrification. After the desulfurization and denitrification are completed, CO2 is captured. The non-decarbonization series flue gas is cooled and dusted before entering the desulfurization and denitrification steps. According to research, the denitrification efficiency of activated carbon is determined by factors such as air velocity, ammonia injection amount, reaction temperature, and activated carbon circulation amount. Table 1 shows the relationship between denitrification rate and air velocity, inlet NO under the conditions of 120°C and an ammonia-nitrogen ratio of 1:1. x The relationship between concentration.

[0050] Table 1

[0051]

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

[0053] ... (Formula 4)

[0054] Where x is the multiple of the air velocity sv0, Y is the denitrification efficiency, and the value range of sv0 is 250~300h -1 According to formula 4, combined with the relationship between denitrification rate and space velocity, ammonia injection amount, reaction temperature, activated carbon circulation amount, and actual operating conditions, formula 1 is further fitted:

[0055] ... (Formula 1)

[0056] Where, Y is the denitrification rate of the decarbonization series flue gas, %; sv0 is the space velocity of activated carbon adsorbing nitrogen oxides, h -1 ; x is a multiple of the air velocity sv0; n is the number of adsorption units in the adsorption tower; v is the filling volume of activated carbon in a single adsorption unit in the adsorption tower, m 3 ; Wherein, x is 0.5-1.2. The values ​​of Y and x for the decarbonized flue gas and the non-decarbonized flue gas are different; Since the concentration of nitrogen oxides at the outlet of the adsorption tower is limited to <50mg / Nm 3 , then determine the value of Y based on the nitrogen oxide concentration in the flue gas from the decarbonization process. The required amount of activated carbon can be calculated as the product of the number of adsorption units n in the adsorption tower and the activated carbon loading volume v of each adsorption unit within the tower. Similarly, the amount of activated carbon introduced for denitrification of non-decarbonization flue gas can be determined, and the amount of activated carbon required for desulfurization of non-decarbonization flue gas can be calculated using Equation 2. Using Equations 1, 2, 3, and 4, the amount of activated carbon introduced during the flue gas purification process can be precisely controlled.

[0057] In the present invention, the value range of Y is based on the NO x Concentration and NO in exhaust gas x The concentration of NO x When the concentration is high, most of the NO x , the value range of Y decreases accordingly. For example, when NO x The concentration is 1000mg / Nm 3 When 3 Below, the value range of Y is 95%~100%. x When the concentration is low, only a portion of the NO needs to be purified. x Then, the value range of Y becomes larger accordingly. For example, when NOx The concentration is 100 mg / Nm 3 When 3 In the following, the value range of Y is 50%~100%.

[0058] In the present invention, in order to minimize the changes in flue gas composition caused by fluctuations in sintered ore or fuel composition, the flue gas in the bellows is determined to be a decarbonization series flue gas based on its composition, and then the bellows is divided into a front bellows or a rear bellows, and enters the subsequent purification step.

[0059] In the present invention, the capture agent that has captured carbon dioxide is heated to 110-130° C. and regenerated for 0.3-1 hour to obtain a regenerated capture agent, which is then recycled to step 2) for repeated use, thereby reducing the decarbonization cost.

[0060] In the present invention, since the sintering machine tail gas, i.e., the non-decarburized flue gas, is at a higher temperature, the decarburized flue gas can be heated by heat exchange with the non-decarburized flue gas. A heat exchange device is provided, and a first flue gas duct is passed through the heat exchange device. The decarburized flue gas in the first flue gas duct is heated by heat exchange with the non-decarburized flue gas. Alternatively, a portion of the non-decarburized flue gas can be fed into the collector heating and regeneration process, fully utilizing the waste heat of the non-decarburized flue gas.

[0061] In the present invention, the flue gas flow rate, circulation volume, etc. are all 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 capturing carbon dioxide and coordinating multiple pollutants in sintering flue gas. According to the flue gas release law during the sintering process, the flue gas is divided into a decarbonization series flue gas and a non-decarbonization series flue gas, which are purified separately to improve the flue gas purification efficiency. The flue gas waste heat is fully utilized according to the performance of the flue gas, thereby achieving full utilization of resources.

[0064] 2. The present invention provides a method for capturing carbon dioxide and coordinating multiple pollutants in sintering flue gas. According to the characteristics of the decarbonization series flue gas and the non-decarbonization series flue gas and the factors affecting the 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] FIG1 is a schematic structural diagram of a system for capturing carbon dioxide and coordinating multiple pollutants from sintering flue gas provided by the present invention.

[0066] FIG2 is another structural schematic diagram of a system for capturing carbon dioxide and coordinating multiple pollutants in sintering flue gas provided by the present invention.

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

[0068] Figure 4 shows the concentration changes of SO2 and CO2 in the sintering flue gas of each wind box during the sintering process.

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

[0070] FIG6 is a diagram showing the temperature variation of the sintering flue gas from each wind box during the sintering process.

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

[0072] Figure 8 shows the temperature variation of the sintering flue gas from the first 20 wind boxes.

[0073] Figure numerals: 1, sintering machine; 2: decarbonization series flue gas duct; 3: non-decarbonization 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 DESCRIPTION

[0074] The technical solutions of the present invention are illustrated below with examples, and the scope of protection requested by the present invention includes but is not limited to the following embodiments.

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

[0076] 1) According to the running direction of the sintering trolley, the bellows under the sintering machine are divided into front bellows and rear bellows. The sintering flue gas in the front bellows and the sintering flue gas in the rear bellows are treated separately. The sintering flue gas in the front bellows is mixed to obtain the decarburized series flue gas, and the sintering flue gas in the rear bellows is mixed to obtain the non-decarburized series flue gas.

[0077] 2) After the decarbonization series flue gas undergoes heating, dust removal, desulfurization and denitrification, and cooling treatments, the CO2 in the decarbonization series flue gas is captured by a capture agent and then discharged through the chimney;

[0078] 3) The non-decarbonized flue gas is sequentially treated with dust removal, desulfurization and denitrification before being discharged through the chimney.

[0079] Preferably, the method further comprises: 4) subjecting the capture agent after adsorbing carbon dioxide in step 2) to thermal regeneration to obtain high-purity carbon dioxide and regenerated capture agent, and returning the regenerated capture agent to step 2) for recycling.

[0080] Preferably, part of the high-temperature flue gas in the rear wind box is subjected to indirect heat exchange with the capture agent after adsorbing carbon dioxide to achieve thermal regeneration of the capture agent.

[0081] Preferably, the decarbonized flue gas in step 1) is: when the temperature of the flue gas in the wind box is 50-100°C, the CO2 concentration is ≥7% (preferably the CO2 concentration is ≥8%), and the SO2 concentration is ≤25mg / Nm 3 (Preferably SO2 concentration ≤ 20 mg / Nm 3 ), the flue gas in the windbox is determined to be a decarburized series flue gas, and the windbox is divided into the front windbox; the non-decarburized series flue gas in step 1) is: when the temperature of the flue gas in the windbox is 50-100°C, or the CO2 concentration is ≤7% (preferably the CO2 concentration is ≤8%), or the SO2 concentration is ≥25mg / Nm 3 (Preferably SO2 concentration ≥ 20mg / Nm 3 ), the flue gas in the bellows is determined to be non-decarburization series flue gas, and the bellows is divided into the rear bellows.

[0082] Preferably, the CO2 capture 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) is to heat the decarburized flue gas to 105-150°C, preferably 110-120°C.

[0085] Preferably, the desulfurization and denitrification in step 2) is carried out by using activated carbon to adsorb a small amount of sulfur dioxide and nitrogen oxides in the decarbonization series flue gas.

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

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

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

[0089] Preferably, the heating in step 2) is performed after heat exchange between the decarburized series flue gas and the non-decarburized series flue gas; preferably, the non-decarburized series flue gas is cooled to 105-150°C, preferably 110-130°C after heat exchange.

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

[0091] As a preference, in the desulfurization and denitrification process, according to the concentration of SO2 and NO in the flue gas, x The concentration is used to calculate the amount of ammonia required to be injected during the desulfurization and denitrification process.

[0092] Preferably, the amount of activated carbon required for the desulfurization and denitrification process is calculated based on the flue gas denitrification, specifically:

[0093] The flow rate of flue gas is measured as Q1, m 3 According to the amount of activated carbon required for flue gas denitrification, the amount of activated carbon required for flue gas purification can be obtained:

[0094] ... (Formula 1)

[0095] Where, Y is the denitrification rate of flue gas, %; sv0 is the space velocity of activated carbon adsorbing nitrogen oxides, h -1 ; x is the multiple of the air velocity; n is the number of adsorption units in the adsorption tower; the filling volume of activated carbon in a single adsorption unit in the adsorption tower is v, m 3 According to the denitrification rate, the amount of activated carbon required to purify the flue gas is calculated by formula 1. .

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

[0097] Preferably, the circulation amount of activated carbon required in the flue gas desulfurization and denitrification process is calculated based on the flue gas desulfurization, specifically:

[0098] The flow rate of flue gas is measured as Q1, m 3 According to the amount of activated carbon required for flue gas desulfurization, the circulation amount of activated carbon required for flue gas purification can be obtained:

[0099] ... (Formula 2)

[0100] Where W is the circulation amount of activated carbon in the adsorption tower, g; C0 is the SO2 concentration in the flue gas at the inlet of the adsorption tower, mg / Nm 3 ; C1 is the SO2 concentration in the gas at the outlet of the adsorption tower, and the value of C1 is 0~35 mg / Nm 3 ; s1 is the adsorption capacity of activated carbon for SO2, mg / g.

[0101] Preferably, the amount of ammonia gas required to be injected during the desulfurization and denitrification process is calculated based on the SO2 concentration and NOx concentration in the flue gas, specifically:

[0102] ... (Formula 3)

[0103] Where C3 is the amount of ammonia required for desulfurization and denitrification, mg / Nm 3 ; C0 is the SO2 concentration at the adsorption tower entrance; C2 is the NO x concentration.

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

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

[0106] A system for capturing carbon dioxide and coordinating multiple pollutants in sintering flue gas is disclosed. The system comprises a sintering machine 1, a decarbonization flue duct 2, a non-decarbonization flue 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 windbox of the sintering machine 1 is divided into a front windbox and a rear windbox, with the front windbox connected to the decarbonization flue duct 2 and the rear windbox connected to the non-decarbonization flue duct 3. The flue gas outlet of the decarbonization flue duct 2 is connected to the flue gas inlet of the heating device 4 via a first flue gas duct 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 duct 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 duct 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 duct L4. The non-decarbonization series flue gas duct 3 is connected to the second desulfurization and denitrification device 6 through the fifth flue gas pipeline L4. The flue gas outlet of the second desulfurization and denitrification device 6 is connected to the chimney 9.

[0107] Preferably, the front bellows are the 1 / 4 to 3 / 4 bellows close to the sintering machine head, and the remaining bellows are the rear bellows.

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

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

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

[0111] Preferably, a temperature detection device and a flue gas component detection device are further provided in the decarburization series flue gas duct 2 and / or the non-decarburization series flue gas duct 3.

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

[0113] Preferably, the system further includes a heat exchanger 15, which is connected to a portion of the tail windbox. The first flue gas duct L1 is disposed through the heat exchanger 15. Preferably, the flue gas outlet of the heat exchanger 15 is connected to the heat source inlet of the trapping agent regeneration device 14. The heat source outlet of the trapping agent regeneration device 14 is connected to the second desulfurization and denitrification device 6.

[0114] Example 1

[0115] A system for capturing carbon dioxide and coordinating multiple pollutants in sintering flue gas is disclosed. The system comprises a sintering machine 1, a decarbonization flue duct 2, a non-decarbonization flue 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 windbox of the sintering machine 1 is divided into a front windbox and a rear windbox, with the front windbox connected to the decarbonization flue duct 2 and the rear windbox connected to the non-decarbonization flue duct 3. The flue gas outlet of the decarbonization flue duct 2 is connected to the flue gas inlet of the heating device 4 via a first flue gas duct 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 duct 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 duct 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 duct L4. The non-decarbonization series flue gas duct 3 is connected to the second desulfurization and denitrification device 6 through the fifth flue gas pipeline L4. The flue gas outlet of the second desulfurization and denitrification device 6 is connected to the chimney 9.

[0116] The front bellows are the 1 / 4 to 3 / 4 bellows close to the sintering machine head, and the remaining bellows are the rear bellows.

[0117] Example 2

[0118] Example 1 was repeated, except that the system also included central windboxes. The central windboxes included five windboxes at the rear end of the front windboxes and three windboxes at the front end of the rear windboxes. Each of the central windboxes was connected to the decarburization series flue gas duct 2 and the non-decarburization series flue gas duct 3 via a three-way branch pipe, and the three-way branch pipe was equipped with a switching valve.

[0119] Example 3

[0120] Example 2 is repeated, except that a first dust removal device 10 and a first fan 11 are provided on the first flue gas duct L1.

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

[0122] Example 4

[0123] Example 3 is repeated, except that a temperature detection device and a flue gas component detection device are further provided in the decarburization series flue gas duct 2 and the non-decarburization series flue gas duct 3.

[0124] Example 5

[0125] Example 4 was repeated, except that the system further included a capture agent regeneration device 14. The capture agent outlet of the carbon dioxide capture device 8 was connected to the capture agent inlet of the capture agent regeneration device 14. The flue gas outlet of the capture agent regeneration device 14 was connected to the chimney 9. The capture agent outlet of the capture agent regeneration device 14 was connected to the capture agent inlet of the carbon dioxide capture device 8.

[0126] Example 6

[0127] Example 5 is repeated, except that the system further includes a heat exchanger 15, which is connected to a portion of the tail windbox. The first flue gas duct L1 is disposed through the heat exchanger 15. Preferably, the flue gas outlet of the heat exchanger 15 is connected to the heat source inlet of the scavenging agent regeneration device 14. The heat source outlet of the scavenging agent regeneration device 14 is connected to the second desulfurization and denitrification device 6.

[0128] Application Example 1

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

[0130] 1) According to the movement direction of the sintering trolley, the flue gas composition in the bellows is detected, and the bellows under the sintering machine are divided into front bellows No. 1 to 15 and rear bellows No. 16 to 28. The sintering flue gas in the front bellows is passed into the decarburization series flue gas duct, and the sintering flue gas in the rear bellows is passed into the non-decarburization series flue gas duct;

[0131] 2) The decarbonization series flue gas is heated to 110°C, passed through the electrostatic precipitator, and then passed into the first desulfurization and denitrification device. After the desulfurization and denitrification are completed, the temperature is reduced to 45°C, and then the flue gas is passed into the carbon dioxide capture device, where the carbon dioxide in the flue gas is captured using an organic amine solution. The clean flue gas is discharged through the chimney;

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

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

[0134]

[0135] Where, Y is the denitrification rate of the decarbonization series flue gas, %; sv0 is the space velocity of activated carbon adsorbing nitrogen oxides, which is taken as 300h -1; x is the multiple of the air velocity, which is 0.9; n is the number of adsorption units in the first desulfurization and denitrification device; the filling volume of activated carbon in a single adsorption unit in the first desulfurization and denitrification device is v, m 3 ;

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

[0137] Activated carbon has high denitrification efficiency, and the SO2 content in the flue gas during decarbonization is low. The activated carbon circulation volume only needs to consider the adsorption of SO2.

[0138] Calculate the circulation amount of activated carbon in the first desulfurization and denitrification device:

[0139]

[0140] Where W1 is the circulation amount of activated carbon in the first desulfurization and denitrification device, t; C0 is the SO2 concentration at the flue gas inlet of the first desulfurization and denitrification device, which is 1173 mg / Nm 3 ; C1 is the SO2 concentration at the flue gas outlet of the first desulfurization and denitrification device, and the value of C1 is 5 mg / Nm 3 ; s1 is the adsorption capacity of activated carbon for SO2, which is 24 mg / g;

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

[0142] At the same time, in the decarbonization system, when NH3 is added, SO2 and NOx will react with NH3 at the same time.

[0143] Ammonia concentration required for desulfurization and denitrification of flue gas:

[0144] .

[0145] Where C3 is the amount of ammonia required for desulfurization and denitrification in the decarbonization series, mg / Nm 3 ; C0 is the SO2 concentration at the flue gas inlet of the first desulfurization and denitrification device; C2 is the NOx concentration at the flue gas inlet of the first desulfurization and denitrification device.

[0146] The first desulfurization and denitrification device uses 6 adsorption units, and the filling volume of activated carbon in each adsorption unit is v=637m 3 The circulation volume of the first desulfurization and denitrification device is controlled to be 0.33t per unit time, and the amount of ammonia required for the decarbonization series desulfurization and denitrification is 177.48mg / Nm 3 .

[0147] 3) After the non-decarbonization series flue gas passes through the electrostatic precipitator, it is passed into the second desulfurization and denitrification device. The clean flue gas after desulfurization and denitrification is discharged through the chimney;

[0148] Among them, the non-decarbonization series flue gas flow rate Q2=650000m 3 The SO2 concentration in the flue gas is 1173 mg / Nm 3 , NO x The concentration is 95mg / Nm 3 .

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

[0150]

[0151] Where, Y' is the denitrification rate of non-decarbonized flue gas, %; sv0 ’ is the space velocity of activated carbon adsorbing nitrogen oxides, which is 300h -1 ; x is the airspeed sv0 ’ The multiple of n is 0.6; ’ is the number of adsorption units in the second desulfurization and denitrification device; ’ The filling volume of activated carbon in a single adsorption unit in the second desulfurization and denitrification device;

[0152] Among them, due to the NO x The concentration is relatively low, at 95 mg / Nm 3 , Y ’ When the value of is 80%, the calculated ’ =4333m 3 ; The number of adsorption units n set in the second desulfurization and denitrification device ’ =6, then the filling volume v of a single adsorption unit activated carbon can be obtained ’ =722m 3 .

[0153] Calculate the circulation amount of activated carbon in the second desulfurization and denitrification device:

[0154]

[0155] Where W2 is the circulation amount of activated carbon in the second desulfurization and denitrification device, t; C0 is the SO2 concentration at the flue gas inlet of the second desulfurization and denitrification device, which is 1173 mg / Nm 3 ; C1 is the SO2 concentration at the flue gas outlet of the second desulfurization and denitrification device, and the value of C1 is 35 mg / Nm 3 ; s1 is the adsorption capacity of activated carbon for SO2, which is 24 mg / g; at the same time, in a non-decarbonized system, when NH3 is added, SO2 and NOx will react with NH3 at the same time.

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

[0157] .

[0158] Where C3 is the amount of ammonia required for denitrification in the non-decarbonization series, mg / Nm 3 ; C0 is the SO2 concentration at the inlet of the second desulfurization and denitrification device; C2 is the NOx concentration at the inlet of the second desulfurization and denitrification device.

[0159] The second desulfurization and denitrification device uses 6 adsorption units, and the filling volume of activated carbon in each adsorption unit is v=722m 3 The circulation volume of the first desulfurization and denitrification device per unit time is controlled to be 30.82t, and the amount of ammonia required for the decarbonization series desulfurization and denitrification is 171.6mg / Nm 3 .

[0160] 4) The capture agent after adsorbing carbon dioxide in step 2) was heated at 120°C for 0.6 hours and regenerated. The regenerated capture agent was circulated to the carbon dioxide capture device, and the resulting CO2 was discharged through the chimney. The purity of the obtained CO2 was 99.3 wt%.

Claims

1. A method for capturing carbon dioxide and coordinating multiple pollutants in sintering flue gas, characterized by: The method includes the following steps: 1) According to the running direction of the sintering trolley, the wind boxes below the sintering machine are divided into front wind boxes and rear wind boxes, and the sintering flue gas in the front wind boxes and the sintering flue gas in the rear wind boxes are treated separately; among them, the sintering flue gas in the front wind boxes is mixed to obtain decarbonized series flue gas, and the sintering flue gas in the rear wind boxes is mixed to obtain non-decarbonized series flue gas; 2) The decarbonized series flue gas is successively subjected to temperature increase, dust removal, desulfurization and denitrification, and temperature reduction treatments, and then a capture agent is used to capture CO2 in the decarbonized series flue gas and is discharged via a chimney; 3) The non-decarbonized series flue gas is successively subjected to dust removal, desulfurization and denitrification treatments and is discharged via a chimney.

2. The method according to claim 1, wherein: The method further includes: 4) The capture agent after adsorbing carbon dioxide in step 2) is subjected to thermal regeneration treatment to obtain high-purity carbon dioxide and a regenerated capture agent, and the regenerated capture agent is returned to step 2) for recycling; Preferably, part of the high-temperature flue gas in the rear wind box is indirectly heat-exchanged with the capture agent after adsorbing carbon dioxide to achieve the thermal regeneration treatment of the capture agent.

3. The method according to claim 1 or 2, characterized in that: Step 1) The decarbonization series flue gas is as follows: when the temperature of the flue gas in the air box is 50 - 100 °C, the CO2 concentration ≥ 7% (preferably CO2 concentration ≥ 8%), and the SO2 concentration ≤ 25 mg / Nm 3 (preferably SO2 concentration ≤ 20 mg / Nm 3 ), it is determined that the flue gas in the air box is decarbonization series flue gas, and this air box is classified into the front air box; The non - decarbonization series flue gas in Step 1) is as follows: when the temperature of the flue gas in the air box is 50 - 100 °C, or the CO2 concentration ≤ 7% (preferably CO2 concentration ≤ 8%), or the SO2 concentration ≥ 25 mg / Nm 3 (preferably SO2 concentration ≥ 20 mg / Nm 3 ), it is determined that the flue gas in the air box is non - decarbonization series flue gas, and this air box is classified into the rear air box.

4. The method according to any one of claims 1 to 3, characterized in that: The CO2 capture agent described in step 2) is an organic amine solution; preferably MDEA, DPMA, MEA or a combination thereof; Preferably, the concentration of the organic amine solution is 20-60 wt.%; the solvent is water, a polar physical solvent or a combination thereof; The temperature increase in step 2) is to increase the temperature of the decarbonized series flue gas to 105-150 °C, preferably 110-120 °C; and / or The desulfurization and denitrification in step 2) is to use activated carbon to adsorb a small amount of sulfur dioxide and nitrogen oxides in the decarbonized series flue gas; and / or The temperature reduction in step 2) is to reduce the temperature of the flue gas after desulfurization and denitrification to 35-60 °C, preferably 40-50 °C and / or The dust removal in steps 2) and 3) is electrostatic precipitation; and / or The desulfurization and denitrification in step 3) is to use activated carbon to adsorb sulfur dioxide and a small amount of nitrogen oxides in the non-decarbonized series flue gas; Preferably, the temperature increase in step 2) is the temperature increase of the decarbonized series flue gas after heat exchange with the non-decarbonized series flue gas; preferably, the non-decarbonized series flue gas is cooled to 105-150 °C after heat exchange, preferably 110-130 °C.

5. The method according to any one of claims 1-4, characterized in that: The activated carbon in the desulfurization and denitrification process in steps 2) and 3) is controlled as follows: According to the flue gas denitrification, the addition amount of activated carbon required in the desulfurization and denitrification process is calculated, and according to the flue gas desulfurization, the circulation amount of activated carbon required in the flue gas desulfurization and denitrification process is calculated; Preferably, during the desulfurization and denitrification process, the amount of ammonia to be injected during the desulfurization and denitrification process is calculated based on the SO2 concentration and NO x concentration in the flue gas.

6. The method according to claim 5, characterized in that: The calculation of the addition amount of activated carbon required in the desulfurization and denitrification process according to the flue gas denitrification is specifically: The measured flue gas flow rate is Q1, m 3 , and according to the amount of activated carbon required for flue gas denitrification, the amount of activated carbon addition required for purifying the flue gas can be obtained: ……(Equation 1) In the formula, Y is the denitration rate of flue gas, %; sv0 is the space velocity of activated carbon for adsorbing nitrogen oxides, h -1 ; x is the multiple of the space velocity; n is the number of adsorption units in the adsorption tower; the loading volume of activated carbon in a single adsorption unit in the adsorption tower is v, m 3 ; according to the requirement of the denitration rate, the addition amount of activated carbon required for purifying the flue gas is calculated by Equation 1 ； Among them, the value of Y is determined by the requirements of flue gas purification in the actual process; the value range of sv0 is 200~500 h -1 , preferably 250~300 h -1 ; the value range of x is 0.5-1.2, preferably 0.6-1; n is an integer greater than or equal to 1; The calculation of the circulation amount of activated carbon required in the flue gas desulfurization and denitrification process according to the flue gas desulfurization is specifically: The measured flue gas flow rate is Q1, m 3 ; According to the amount of activated carbon required for flue gas desulfurization, the circulation amount of activated carbon required for purifying the flue gas can be obtained: ……(Equation 2) Wherein, W is the circulation amount of activated carbon in the adsorption tower, in g; C0 is the concentration of SO2 in the flue gas at the inlet of the adsorption tower, in mg / Nm 3 ; C1 is the concentration of SO2 in the gas at the outlet of the adsorption tower, and the value of C1 is 0 to 35 mg / Nm 3 ; s1 is the adsorption capacity of activated carbon for SO2, in mg / g; The amount of ammonia gas to be injected required in the desulfurization and denitrification process is calculated according to the SO2 concentration and NOx concentration in the flue gas, specifically: ……(Equation 3) where C3 is the ammonia gas volume required for desulfurization and denitrification, mg / Nm 3 ; C0 is the SO2 concentration at the inlet of the adsorption tower; C2 is the NO x concentration at the inlet of the adsorption tower.

7. The method according to claim 2, characterized in that: The thermal regeneration treatment of the capture agent described in step 4) is: heating the capture agent to 110-130 °C and regenerating for 0.3-1 h to obtain a regenerated capture agent.

8. A system for co-capturing carbon dioxide and treating multiple pollutants in sintering flue gas or a system applied to the method according to any one of claims 1-7, characterized in that: 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 temperature reduction 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 decarbonization series flue gas duct (2), and the rear air box is connected to the non-decarbonization series flue gas duct (3); the flue gas outlet of the decarbonization series flue gas duct (2) is communicated with the flue gas inlet of the heating device (4) through a first flue gas pipeline (L1); the flue gas outlet of the heating device (4) is communicated with the flue gas inlet of the first desulfurization and denitrification device (5) through a second flue gas pipeline (L2); the flue gas inlet of the first desulfurization and denitrification device (5) is communicated with the flue gas inlet of the temperature reduction device (7) through a third flue gas pipeline (L3); the flue gas outlet of the temperature reduction device (7) is communicated with the flue gas inlet of the carbon dioxide capture device (8) through a fourth flue gas pipeline (L4); the non-decarbonization series flue gas duct (3) is connected to the second desulfurization and denitrification device (6) through a fifth flue gas pipeline (L5); the flue gas outlet of the second desulfurization and denitrification device (6) is connected to a chimney (9); Preferably, the front air box is the air box from 1 / 4 to 3 / 4 close to the head of the sintering machine, and the remaining air boxes are rear air boxes; As a preference, the system further includes a middle air box; the middle air box includes some air boxes at the tail end of the front air box and / or some air boxes at the front end of the rear air box; any one of the middle air boxes is connected to the decarbonization series flue gas duct (2) and the non-decarbonization series flue gas duct (3) through a three-way branch pipe, and a switching valve is provided at the three-way branch pipe.

9. The system according to claim 8, wherein: A first dust removal device (10) and a first fan (11) are provided on the second flue gas pipeline (L2); and / or A second dust removal device (12) and a second fan (13) are provided on the fifth flue gas pipeline (L5); and / or A temperature detection device and a flue gas component detection device are further provided in the decarbonization series flue gas duct (2) and / or the non-decarbonization series flue gas duct (3).

10. The system according to claim 8 or 9, characterized in that: The system further includes a capture agent regeneration device (14); the capture agent outlet of the carbon dioxide capture device (8) is communicated with the capture agent inlet of the capture agent regeneration device (14); the flue gas outlet of the capture agent regeneration device (14) is connected to the chimney (9); preferably, the capture agent outlet of the capture agent regeneration device (14) is communicated with the capture agent inlet of the carbon dioxide capture device (8). Preferably, the system further includes a heat exchange device (15), and the heat exchange device (15) is communicated with some tail air boxes; the first flue gas pipeline (L1) is arranged through the heat exchange device (15); preferably, the flue gas outlet of the heat exchange device (15) is communicated with the heat source inlet of the capture agent regeneration device (14); the heat source outlet of the capture agent regeneration device (14) is connected to the second desulfurization and denitrification device (6).

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