Flue gas double-circulation sintering system and application thereof

Abstract

The invention provides a flue gas double-circulation sintering system and application thereof, and relates to the technical field of sintering. According to the flue gas double-circulation sintering system provided by the invention, the sintering flue gas is subjected to segmented double-circulation treatment, and the flue gas with high CO content generated by the ignition section is conveyed to a high-temperature area to serve as fuel for secondary combustion, so that CO in the flue gas is fully oxidized into CO2; flue gas of the tail section and the cooling section is conveyed to a sintering material layer in the pre-sintering section, the first calcining section and the second calcining section, harmful ingredients in the sintering flue gas enter the sintering material layer again to be thermally decomposed or converted, dioxin, nitric oxide, CO and the like can be partially eliminated, generation of the nitric oxide is inhibited, and the emission amount of dust and sulfur dioxide is reduced; sintering flue gas in the three areas is circulated, and the flue gas circulation utilization rate can be increased to 50% from 20% at present; the problem that at present, the circulation rate of sintering flue gas is low is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of sintering, and in particular, to a flue gas double-circulation sintering system and its application. Background Art

[0002] The flue gas emissions in the sintered ore production process are mainly concentrated in the sintering process. Currently, for each ton of sintered ore produced, 4000-6000 m 3 of sintering flue gas is generated. The sintering flue gas emissions account for about half of the flue gas emissions in iron and steel production. Moreover, in addition to water vapor, the sintering flue gas generated in the sintering process also contains pollutants such as CO, CO2, SO2, NO x , dioxins, etc. Due to the large volume of sintering flue gas, complex composition, high treatment cost and low efficiency, the treatment of sintering flue gas pollution has become an important link restricting the sustainable development of the iron and steel industry.

[0003] Although desulfurization and denitrification devices are currently commonly used to treat sintering flue gas, due to the large volume of sintering flue gas, the low concentrations of pollutants such as SO2 and NO x after the flue gas is mixed, and the need to heat the low-temperature flue gas to the temperature required for the selective catalytic reduction (SCR) reaction of flue gas denitrification or to perform catalytic oxidation, the sintering flue gas treatment facilities are increasing, occupying more and more land, and the construction and operation costs are continuously rising.

[0004] At the beginning of this century, Baosteel and Ningbo Iron and Steel took the lead in recycling some of the sintering hot flue gas, reducing the amount of flue gas discharged and recovering some of the waste heat of the waste gas at the same time, reducing the treatment load of the purification facilities, and also reducing the consumption of sintered solid fuel. Subsequently, other domestic enterprises further studied various flue gas circulation schemes on this basis. However, the circulation utilization rate of sintering flue gas has always been maintained within the range of 20%-30%, and a large amount of flue gas is still discharged, wasting energy and not achieving the ideal energy-saving and emission-reduction effect. Therefore, how to more effectively utilize sintering flue gas is an urgent problem to be solved in the current field of sintering flue gas treatment. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a flue gas double-circulation sintering system and its application. The flue gas double-circulation sintering system has the advantages of high circulation utilization rate of sintering flue gas, low construction and operation costs, and good energy-saving and emission-reduction effects.

[0006] The specific technical solution of the present invention is as follows: The present invention provides a flue gas double - circulation sintering system, which includes a sintering machine, a first flue gas pipeline and a second flue gas pipeline. The sintering machine is divided into multiple zones along the traveling direction of the trolley. The multiple zones are sequentially the ignition zone, the pre - sintering zone, the first calcination zone, the second calcination zone, the tail section and the cooling zone along the traveling direction of the trolley. The sintering flue gas generated in the ignition zone enters the first flue gas pipeline, and the sintering flue gas generated in the tail section and the cooling zone enters the second flue gas pipeline; The outlet of the first flue gas pipeline is arranged on the sintering material layer in at least one zone of the tail section and the cooling zone to transport the sintering flue gas generated in the ignition zone, forming a first circulation; the outlet of the second flue gas pipeline is arranged on the sintering material layer in the pre - sintering zone, the first calcination zone and the second calcination zone to transport the sintering flue gas generated in the tail section and the cooling zone, forming a second circulation.

[0007] The energy - saving and emission - reduction sintering system provided by the present invention divides the sintering machine into six zones: the ignition zone, the pre - sintering zone, the first calcination zone, the second calcination zone, the tail section and the cooling zone. The sintering flue gas is processed by double - circulation in sections. By transporting the flue gas in the ignition zone to the surface of the sintering material layer in at least one zone of the tail section and the cooling zone, the flue gas with a high CO content generated in the ignition zone is transported to a high - temperature area and used as fuel for secondary combustion, so that the CO in the flue gas is fully oxidized into CO2. While reducing the pollutant emissions of the flue gas in the ignition zone, the sintering flue gas in the ignition zone is also rapidly heated after heat exchange in at least one zone of the cooling zone and the tail section; by transporting the sintering flue gas in the tail section and the cooling zone to the sintering material layer in the pre - sintering zone, the first calcination zone and the second calcination zone, the harmful components in the sintering flue gas enter the sintering material layer again to be thermally decomposed or transformed, and dioxins, nitrogen oxides, CO, etc. will be partially eliminated, and the generation of nitrogen oxides is inhibited, reducing the emissions of dust and sulfur dioxide; and the sintering flue gas generated by the sintering machine is mainly concentrated in the ignition zone, the tail section and the cooling zone. By circulating the sintering flue gas in these three zones, the flue gas circulation utilization rate can be increased from the current 20% to 50%; at the same time, by transporting the sintering flue gas to the pre - sintering zone, the first calcination zone and the second calcination zone for centralized desulfurization and denitrification treatment and centralized emission, the project investment is also reduced and the operation cost is lowered, achieving the effect of energy conservation and emission reduction.

[0008] Preferably, a plurality of air boxes are arranged in each zone, and a regulating valve is connected to the outlet of each air box. All the corresponding regulating valves in each zone are jointly connected to a dust removal device; the outlet of the dust removal device in each zone is connected to an exhaust mechanism. In the ignition zone, the outlet of the exhaust mechanism is connected to the first flue gas pipeline; in the pre - sintering zone, the first calcination zone and the second calcination zone, the outlet of the exhaust mechanism is connected to a chimney; in the tail section and the cooling zone, the outlet of the exhaust mechanism is connected to the second flue gas pipeline.

[0009] Preferably, it further includes a flue gas mixing device and a plurality of circulating flue gas hoods arranged above the sintering material layer. The flue gas mixing device is arranged in the middle of the second flue gas pipeline. The flue gas mixing device has two inlets. The first inlet and outlet of the flue gas mixing device are communicated with the second flue gas pipeline. The inlets of all the circulating flue gas hoods are respectively communicated with the first flue gas pipeline and the second flue gas pipeline. A ventilation port is arranged on the circulating flue gas hood. The second inlet of the flue gas mixing device and the ventilation ports on each circulating flue gas hood are all communicated with a gas regulating valve. The gas regulating valve is communicated with an external gas source or an oxygen increasing device. By supplementing hot waste gas, oxygen or air through the gas regulating valve, a mixed sintering flue gas with an oxygen content greater than 19% is formed in the mixing air duct, which is more suitable for subsequent recycling. By adjusting the amount of sintering flue gas in the flue gas pipeline, when the sintering flue gas circulates to above the sintering material layer in the circulating flue gas hood, the air pressure in the circulating flue gas hood is maintained at a slightly negative pressure.

[0010] Preferably, flue gas parameter detection devices are arranged on the outlet pipeline of the air box, the first flue gas pipeline and the second flue gas pipeline, and are used for detecting the performance parameters of the sintering flue gas.

[0011] Preferably, the flue gas parameter detection device includes at least one of an oxygen meter, a temperature and humidity meter, a pressure gauge, a NOx sensor, a SO2 sensor, a CO sensor and a CO2 sensor. According to the performance data of the sintering flue gas detected by the flue gas parameter detection device, intelligent analysis and judgment are carried out, and then the operation parameters of other equipment in the double-cycle sintering flue gas system are controlled to realize centralized management and control.

[0012] Preferably, the dust removal device includes a dust collector, a pneumatic conveying device and a ash bin. The inlet of the dust collector is communicated with the outlet of the regulating valve. The dust collector has two outlets. The first outlet of the dust collector is communicated with the inlet of the exhaust mechanism. The second outlet of the dust collector is communicated with the ash bin through the pneumatic conveying device. By adopting a dust removal device including a dust collector, a pneumatic conveying device and an ash bin, while removing the dust in the flue gas, the dust collected in the dust collector can also be sent to the ash bin for centralized recovery and treatment, so as to realize the unified discharge of dust and solve the problem of difficult dust recovery in decentralized dust removal at the same time.

[0013] Preferably, in the pre-burning section, the first calcination section and the second calcination section, the exhaust mechanism includes a desulfurization and denitrification device and a fan. The outlet of the desulfurization and denitrification device is communicated with the inlet of the fan. The inlet of the desulfurization and denitrification device is communicated with the outlet of the dust collector.

[0014] Preferably, in the ignition section, the tail section and the cooling section, the exhaust mechanism includes a fan. The inlet of the fan is communicated with the outlet of the dust collector.

[0015] Preferably, the bellow, the flue gas parameter detection device, the regulating valve, the dust removal device, the circulating smoke hood, the exhaust mechanism and the flue gas mixing device are electrically connected to a control module.

[0016] The present invention also provides an application of the above-mentioned double-cycle sintering system for flue gas in iron and steel smelting.

[0017] The positive and progressive effects of the present invention are as follows: (1) The double-cycle sintering system for flue gas provided by the present invention performs segmented double-cycle treatment on sintering flue gas, enabling harmful components in the sintering flue gas to re-enter the sintering material layer for thermal decomposition or conversion. Dioxins, nitrogen oxides, CO, etc. will be partially eliminated, the generation of nitrogen oxides will be inhibited, the emissions of dust and sulfur dioxide will be reduced, and carbon monoxide in the flue gas will be reused as fuel. Finally, the circulation rate of the sintering flue gas reaches about 50%, significantly reducing the total emissions of sintering flue gas. The double-cycle sintering system for flue gas not only recovers the heat of the flue gas but also reduces the load of pollutant treatment equipment, lowering the investment and operating costs of treatment, achieving the technical effects of green dust reduction, energy conservation, and carbon reduction. (2) The double-cycle sintering system for flue gas provided by the present invention returns the sintering flue gas generated in three regions with high oxygen content to the sintering machine again and uses it as combustion-supporting gas, utilizing the hot air sintering technology, which can effectively improve the drum index of sintered ore and achieve the effect of improving the quality of sintered ore products. Description of the Drawings

[0018] Figure 1 It is a schematic structural diagram of the double-cycle sintering system for flue gas in Example 1; Figure 2 It is a schematic structural diagram of the double-cycle sintering system for flue gas in Example 2; Figure 3 It is a schematic structural diagram of the double-cycle sintering system for flue gas in Example 3; Figure 4 It is a temperature data graph of the flue gas generated in six regions of the sintering machine before flue gas circulation; Figure 5 It is a flow rate data graph of the flue gas generated in six regions of the sintering machine before flue gas circulation; Figure 6 It is an O2 and CO2 content data graph of the flue gas generated in six regions of the sintering machine before flue gas circulation; Figure 7 It is NO x and SO2 content data graph of the flue gas generated in six regions of the sintering machine before flue gas circulation; Figure 8 It is a CO content data graph of the flue gas generated in six regions of the sintering machine before flue gas circulation.

[0019] Description of the Reference Numerals 1. Sintering machine; 2. Wind box; 3. Flue gas parameter detection device; 4. Mixed air duct; 5. Control valve; 6. Dust collector; 7. Desulfurization and denitrification device; 8. Fan; 9. Control module; 10. Circulating smoke hood; 11. Flue gas mixing device; 12. Pneumatic conveying device; 13. Ash bin; 14. Chimney; 15. First flue gas pipeline; 16. Second flue gas pipeline; 17. Gas control valve. Detailed implementation manners

[0020] To make the above objects, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below. It should be noted that the following implementation manners are only used to explain the technical principle of the embodiments of the present application, and are not intended to limit the protection scope of the embodiments of the present application. Those skilled in the art can adjust it as needed to adapt to specific application scenarios.

[0021] Unless otherwise clearly defined and limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific situations.

[0022] In the embodiments of the present application, unless otherwise clearly defined and limited, a first feature being "on" or "under" a second feature can be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0023] The following combines the appended Figure 1-8 and specific embodiments to further describe the present application in detail.

[0024] Embodiment 1 This embodiment provides an energy-saving and emission-reduction sintering system. Figure 1It is a structural schematic diagram. The sintering machine 1 is divided into six regions along the traveling direction of the trolley, which are the ignition section, the pre-sintering section, the first calcination section, the second calcination section, the tail section, and the cooling section in sequence. There are 23 wind boxes 2 arranged below the trolley of the sintering machine 1. The A - D wind boxes 2 are for the ignition section, the E - H wind boxes 2 are for the pre-sintering section, the I - L wind boxes 2 are for the first calcination section, the M - P wind boxes 2 are for the second calcination section, the Q - T wind boxes 2 are for the tail section, and the U - W wind boxes 2 are for the cooling section. Flue gas parameter detection devices 3 are installed on all the A - W wind boxes 2, and the air pressure and air volume of the A - W wind boxes 2 can be adjusted according to the performance data of the flue gas detected by the flue gas parameter detection devices 3. The flue gas parameter detection devices 3 are oxygen meters, temperature and humidity meters, pressure gauges, NO x sensors, SO2 sensors, CO sensors, and CO2 sensors. According to the performance data of the sintering flue gas detected by the flue gas parameter detection devices 3, intelligent analysis and judgment are carried out, and then the operating parameters of other equipment in the flue gas double-cycle sintering system are controlled to achieve centralized management and control. The A - W wind boxes 2 are respectively connected to the dust collectors 6 in the corresponding regions through the mixing air pipes 4. A regulating valve 5 is installed on the mixing air pipe 4. The mixing air pipe 4 and the corresponding dust collector 6 are connected in parallel in a longitudinal straight-through manner, which can reduce the system resistance. The dust collector 6 is connected to an exhaust mechanism.

[0025] In the ignition section, the exhaust mechanism includes a fan 8. The outlets of the A - D wind boxes 2 are respectively connected to the inlets of four mixing air pipes 4. The outlets of the four mixing air pipes 4 are connected to the inlet of the A1 dust collector 6. The four mixing air pipes 4 and the A1 dust collector 6 are connected in parallel in a longitudinal straight-through manner. The A1 dust collector 6 has two outlets. The first outlet of the A1 dust collector 6 is connected to the inlet of the F1 fan 8. The second outlet of the A1 dust collector 6 is connected to the inlet of the pneumatic conveying device 12. The outlet of the pneumatic conveying device 12 is connected to the ash bin 13. The A1 dust collector 6 and the F1 fan 8 are connected in a longitudinal straight-through manner. The A1 dust collector 6 is a plastic plate dust collector.

[0026] In the pre-sintering section, the exhaust mechanism includes a desulfurization and denitrification device 7 and a blower 8. The outlets of air boxes 2 from E to H are respectively connected to the inlets of four mixing air ducts 4. The outlets of the four mixing air ducts 4 are connected to the inlet of a dust collector A2. The four mixing air ducts 4 and the dust collector A2 are connected in parallel in a longitudinal straight-through manner. The dust collector A2 has two outlets. The first outlet of the dust collector A2 is connected to the inlet of the desulfurization and denitrification device T2. The second outlet of the dust collector A2 is connected to the inlet of a pneumatic conveying device 12. The outlet of the desulfurization and denitrification device T2 is connected to the inlet of a blower F2. The outlet of the pneumatic conveying device 12 is connected to a ash bin 13. The outlet of the blower F2 is connected to a chimney 14. The dust collector A2, the desulfurization and denitrification device T2 and the blower F2 are connected in a longitudinal straight-through manner. The dust collector A2 is a plastic plate dust collector. The desulfurization and denitrification device T2 uses the ozone oxidation desulfurization and denitrification method. Above the sintered material layer in the pre-sintering section, there is a circulating smoke hood M1 with two inlets. The first inlet of the circulating smoke hood M1 is connected to a second flue gas pipeline 16. The second inlet of the circulating smoke hood M1 is connected to an external gas source or an oxygen enrichment device through a gas regulating valve TF1. By supplementing hot waste gas, oxygen or air through the gas regulating valve 17, a mixed sintering flue gas with an oxygen content of 19-20% is formed in the mixing air duct 4, which is more suitable for subsequent recycling.

[0027] In the first calcination section, the exhaust mechanism includes a desulfurization and denitrification device 7 and a blower 8. The outlets of air boxes 2 from I to L are respectively connected to the inlets of four mixing air ducts 4. The outlets of the four mixing air ducts 4 are connected to the inlet of a dust collector A3. The four mixing air ducts 4 and the dust collector A3 are connected in parallel in a longitudinal straight-through manner. The dust collector A3 has two outlets. The first outlet of the dust collector A3 is connected to the inlet of the desulfurization and denitrification device T3. The second outlet of the dust collector A3 is connected to the inlet of a pneumatic conveying device 12. The outlet of the desulfurization and denitrification device T3 is connected to the inlet of a blower F3. The outlet of the pneumatic conveying device 12 is connected to a ash bin 13. The outlet of the blower F3 is connected to a chimney 14. The dust collector A3, the desulfurization and denitrification device T3 and the blower F3 are connected in a longitudinal straight-through manner. The dust collector A3 is a two-stage dust removal device. The first stage is a cyclone dust collector, and the second stage is a cartridge dust collector; the desulfurization and denitrification device T3 uses the ozone oxidation desulfurization and denitrification method. Above the sintered material layer in the first calcination section, there is a circulating smoke hood M2 with two inlets. The first inlet of the circulating smoke hood M2 is connected to a second flue gas pipeline 16. The second inlet of the circulating smoke hood M2 is connected to an external gas source or an oxygen enrichment device through a gas regulating valve TF2.

[0028] In the second calcination stage, the exhaust mechanism includes a desulfurization and denitrification device 7 and a blower 8. The outlets of the air boxes 2 numbered M - P are respectively connected to the inlets of four mixing air pipes 4. The outlets of the four mixing air pipes 4 are connected to the inlet of a dust collector 6 numbered A4. The four mixing air pipes 4 and the dust collector 6 numbered A4 are connected in parallel in a longitudinal straight - through manner. The dust collector 6 numbered A4 has two outlets. The first outlet of the dust collector 6 numbered A4 is connected to the inlet of the desulfurization and denitrification device 7 numbered T4. The second outlet of the dust collector 6 numbered A4 is connected to the inlet of a pneumatic conveying device 12. The outlet of the desulfurization and denitrification device 7 numbered T4 is connected to the inlet of a blower 8 numbered F4. The outlet of the pneumatic conveying device 12 is connected to a ash bin 13. The outlet of the blower 8 numbered F3 is connected to a chimney 14. The dust collector 6 numbered A4, the desulfurization and denitrification device 7 numbered T4, and the blower 8 numbered F4 are connected in a longitudinal straight - through manner. The dust collector 6 numbered A4 is a two - stage dust removal device. The first stage is a multi - tube dust collector, and the second stage is a bag - type dust collector. The desulfurization and denitrification device 7 numbered T4 uses the zeolite catalytic combustion desulfurization and denitrification method. Above the sintered material layer in the second calcination stage, there is a circulating smoke hood 10 numbered M3. The circulating smoke hood 10 numbered M3 has two inlets. The first inlet of the circulating smoke hood 10 numbered M3 is connected to a second flue gas pipeline 16. The second inlet of the circulating smoke hood 10 numbered M3 is connected to an external gas source or an oxygen - increasing device through a gas regulating valve 17 numbered TF3.

[0029] In the tail section, the exhaust mechanism includes a blower 8. The outlets of the air boxes 2 numbered Q - T are respectively connected to the inlets of four mixing air pipes 4. The outlets of the four mixing air pipes 4 are connected to the inlet of a dust collector 6 numbered A5. The four mixing air pipes 4 and the dust collector 6 numbered A5 are connected in parallel in a longitudinal straight - through manner. The dust collector 6 numbered A5 has two outlets. The first outlet of the dust collector 6 numbered A5 is connected to the inlet of a blower 8 numbered F5. The second outlet of the dust collector 6 numbered A5 is connected to the inlet of a pneumatic conveying device 12. The outlet of the pneumatic conveying device 12 is connected to a ash bin 13. The outlet of the blower 8 numbered F5 is connected to a flue gas mixing device 11 numbered H1 through a second flue gas pipeline 16. The outlet of the flue gas mixing device 11 numbered H1 is connected to the circulating smoke hoods 10 numbered M1, M2, and M3 through a second flue gas pipeline 16. Between the flue gas mixing device 11 numbered H1 and the circulating smoke hoods 10 numbered M1, M2, and M3, there are respectively provided gas regulating valves 5. The flue gas mixing device 11 numbered H1 is also connected to an external gas source or an oxygen - increasing device through a gas regulating valve 17 numbered TF6. The dust collector 6 numbered A5 and the blower 8 numbered F5 are connected in a longitudinal straight - through manner. The dust collector 6 numbered A5 is a two - stage dust removal device. The first stage is a cyclone dust collector, and the second stage is a bag - type dust collector.

[0030] In the cooling section, the exhaust mechanism includes a blower 8. The outlets of the air boxes 2 numbered U - W are respectively connected to the inlets of four mixing air ducts 4. The outlets of the four mixing air ducts 4 are connected to the inlet of the dust collector 6 numbered A6. The four mixing air ducts 4 and the dust collector 6 numbered A6 are connected in parallel in a longitudinal straight - through manner. The dust collector 6 numbered A6 has two outlets. The first outlet of the dust collector 6 numbered A6 is connected to the inlet of the blower 8 numbered F6, and the second outlet of the dust collector 6 numbered A6 is connected to the inlet of the pneumatic conveying device 12. The outlet of the pneumatic conveying device 12 is connected to the ash bin 13. The outlet of the blower 8 numbered F6 is connected to the flue gas mixing device 11 numbered H1 through the second flue gas pipe 16. Above the sintering material layer in the cooling section, there is a circulating smoke hood 10 numbered M4. The circulating smoke hood 10 numbered M4 has two inlets. The outlet of the blower 8 numbered F1 in the ignition section is connected to the first inlet of the circulating smoke hood 10 numbered M4 through the first flue gas pipe 15. The second inlet of the circulating smoke hood 10 numbered M4 is connected to an external air source or an oxygen - increasing device through a gas regulating valve 17 numbered TF4. The dust collector 6 numbered A6 and the blower 8 numbered F6 are connected in a longitudinal straight - through manner; the dust collector 6 numbered A6 is a two - stage dust removal device. The first stage is a multi - tube dust collector, and the second stage is a cartridge dust collector.

[0031] It should be noted that by adjusting the amount of sintering flue gas in the first flue gas pipe 15 and the second flue gas pipe 16, when the sintering flue gas is circulated above the sintering material layer in the circulating smoke hood 10, the air pressure in the circulating smoke hood 10 can be maintained at a slightly negative pressure.

[0032] By adopting a dust removal device including the dust collector 6, the pneumatic conveying device 12, and the ash bin 13, while removing the dust in the flue gas, the dust collected in the dust collector 6 can also be sent to the ash bin 13 for centralized recovery and treatment, so as to achieve the unified discharge of dust and solve the problem of difficult dust recovery in decentralized dust removal at the same time.

[0033] The air box 2, the flue gas parameter detection device 3, the regulating valve 5, the dust collector 6, the desulfurization and denitrification device 7, the blower 8, the flue gas mixing device 11, the pneumatic conveying device 12, and the gas regulating valve 17 are electrically connected to the control module 9, enabling intelligent control.

[0034] By transporting the flue gas in the ignition section to the cooling section, the flue gas with a high CO content generated in the ignition section is transported to the high-temperature area and used as fuel for secondary combustion, enabling the CO in the flue gas to be fully oxidized into CO2. While reducing the pollutant emissions of the flue gas in the ignition section, the sintering flue gas in the ignition section can also be rapidly heated after heat exchange in the cooling section; by transporting the sintering flue gas in the tail section and the cooling section to the sintering material layers in the preheating section, the first calcination section, and the second calcination section, the harmful components in the sintering flue gas can enter the sintering material layer again to be thermally decomposed or transformed, and dioxins, nitrogen oxides, CO, etc. will be partially eliminated, and the generation of nitrogen oxides will be inhibited, reducing the emissions of dust and sulfur dioxide; and the sintering flue gas generated by the sintering machine 1 is mainly concentrated in the ignition section, the tail section, and the cooling section. By circulating the sintering flue gas in these three areas, the flue gas circulation utilization rate can be increased from the current 20% to 50%; at the same time, by transporting the sintering flue gas to the preheating section, the first calcination section, and the second calcination section for centralized desulfurization and denitrification treatment and centralized emission, the project investment is also reduced and the operation cost is lowered, achieving the effect of energy conservation and emission reduction.

[0035] The main performance parameters and treatment methods of the flue gas generated in the six areas of the sintering machine 1 along the traveling direction of the trolley are shown in Table 1.

[0036] Table 1 Main performance parameters and treatment methods of the flue gas generated in the six areas Figure 4 It is a temperature data diagram of the flue gas generated in the six areas of the sintering machine 1 before flue gas circulation. It can be seen from the figure that the temperatures of the flue gas generated in the ignition section, the preheating section, and the first calcination section are relatively low, below 100 °C; while the temperatures of the flue gas generated in the second calcination section, the tail section, and the cooling section are relatively high. The temperatures of the flue gas generated in the second calcination section and the tail section are between 100 - 200 °C, and the temperature of the flue gas generated in the cooling section is between 200 - 350 °C.

[0037] Figure 5 It is a flow velocity data diagram of the flue gas generated in the six areas of the sintering machine 1 before flue gas circulation. It can be seen from the figure that the flow velocities of the flue gas generated in the ignition section, the preheating section, the first calcination section, and the second calcination section are relatively low, below 15 m / s; while the flow velocities of the flue gas generated in the tail section and the cooling section are relatively high, reaching up to more than 35 m / s at most.

[0038] Figure 6 It is an O2 and CO2 content data diagram of the flue gas generated in the six areas of the sintering machine 1 before flue gas circulation. It can be seen from the figure that compared with the flue gas generated in the preheating section and the first calcination section, the O2 content in the flue gas generated in the ignition section, the second calcination section, the tail section, and the cooling section is relatively high, while the CO2 content is relatively low.

[0039] Figure 7The content data diagrams of NO x and SO2 in the flue gas generated by the six regions of the sintering machine 1 before flue gas circulation. It can be seen from the figure that compared with the ignition section and the pre-calcination section, the content of SO2 in the flue gas generated by the first calcination section, the second calcination section, the tail section and the cooling section is relatively high, while the content of NO x is relatively low.

[0040] Figure 8 The content data diagram of CO in the flue gas generated by the six regions of the sintering machine 1 before flue gas circulation. It can be seen from the figure that along the traveling direction of the trolley, the content of CO in the flue gas generated by the ignition section, the pre-calcination section, the first calcination section, the second calcination section, the tail section and the cooling section generally shows a trend of being low at both ends and high in the middle.

[0041] Example 2 This example provides an energy-saving and emission-reduction sintering system, Figure 2 As its structural schematic diagram, the sintering machine 1 is divided into six regions along the traveling direction of the trolley, which are the ignition section, the pre-calcination section, the first calcination section, the second calcination section, the tail section and the cooling section in sequence. There are 23 wind boxes 2 arranged under the trolley of the sintering machine 1. The A-D wind boxes 2 are the ignition section, the E-H wind boxes 2 are the pre-calcination section, the I-L wind boxes 2 are the first calcination section, the M-P wind boxes 2 are the second calcination section, the Q-T wind boxes 2 are the tail section, and the U-W wind boxes 2 are the cooling section. Flue gas parameter detection devices 3 are arranged on all the A-W wind boxes 2, and the air pressure and air volume of the A-W wind boxes 2 can be adjusted according to the performance data of the flue gas detected by the flue gas parameter detection devices 3. The flue gas parameter detection devices 3 are oxygen meters, temperature and humidity meters, pressure gauges, NO x sensors, SO2 sensors, CO sensors and CO2 sensors. The A-W wind boxes 2 are respectively connected to the dust removal devices in the corresponding regions through mixing air ducts 4. A regulating valve 5 is arranged on the mixing air ducts 4. The mixing air ducts 4 are arranged in a parallel longitudinal straight-through manner, which can reduce the system resistance.

[0042] In the ignition section, the exhaust mechanism includes a fan 8. The outlets of the A-D wind boxes 2 are respectively connected to the inlets of four mixing air ducts 4. The outlets of the four mixing air ducts 4 are connected to the inlet of the A1 dust collector 6. The four mixing air ducts 4 are connected to the A1 dust collector 6 in a parallel longitudinal straight-through manner. The A1 dust collector 6 has two outlets. The first outlet of the A1 dust collector 6 is connected to the inlet of the F1 fan 8. The second outlet of the A1 dust collector 6 is connected to the inlet of the pneumatic conveying device 12. The outlet of the pneumatic conveying device 12 is connected to the ash bin 13. The A1 dust collector 6 and the F1 fan 8 are connected in a longitudinal straight-through manner. The A1 dust collector 6 is a plastic plate dust collector.

[0043] In the pre - calcination section, the exhaust mechanism includes a desulfurization and denitrification device 7 and a blower 8. The outlets of the air boxes 2 from E to H are respectively connected to the inlets of four mixing air ducts 4. The outlets of the four mixing air ducts 4 are connected to the inlet of the A2 dust collector 6. The four mixing air ducts 4 and the A2 dust collector 6 are connected in parallel in a longitudinal straight - through manner. The A2 dust collector 6 has two outlets. The first outlet of the A2 dust collector 6 is connected to the inlet of the T2 desulfurization and denitrification device 7. The second outlet of the A2 dust collector 6 is connected to the inlet of the pneumatic conveying device 12. The outlet of the T2 desulfurization and denitrification device 7 is connected to the inlet of the F2 blower 8. The outlet of the pneumatic conveying device 12 is connected to the ash bin 13. The outlet of the F2 blower 8 is connected to the chimney 14. The A2 dust collector 6, the T2 desulfurization and denitrification device 7, and the F2 blower 8 are connected in a longitudinal straight - through manner. The A2 dust collector 6 is a plastic - plate dust collector. The T2 desulfurization and denitrification device 7 uses the ozone - oxidation desulfurization and denitrification method. Above the sintering material layer in the pre - calcination section, there is an M1 circulating smoke hood 10. The M1 circulating smoke hood 10 has two inlets. The first inlet of the M1 circulating smoke hood 10 is connected to the second flue gas pipeline 16. The second inlet of the M1 circulating smoke hood 10 is connected to an external gas source or an oxygen - increasing device through the TF1 gas regulating valve 17. By supplementing hot waste gas, oxygen, or air through the gas regulating valve 17, a mixed sintering flue gas with an oxygen content of 19 - 20% is formed in the mixing air duct 4, which is more suitable for subsequent recycling.

[0044] In the first calcination section, the exhaust mechanism includes a desulfurization and denitrification device 7 and a blower 8. The outlets of the air boxes 2 from I to L are respectively connected to the inlets of four mixing air ducts 4. The outlets of the four mixing air ducts 4 are connected to the inlet of the A3 dust collector 6. The four mixing air ducts 4 and the A3 dust collector 6 are connected in parallel in a longitudinal straight - through manner. The A3 dust collector 6 has two outlets. The first outlet of the A3 dust collector 6 is connected to the inlet of the T3 desulfurization and denitrification device 7. The second outlet of the A3 dust collector 6 is connected to the inlet of the pneumatic conveying device 12. The outlet of the T3 desulfurization and denitrification device 7 is connected to the inlet of the F3 blower 8. The outlet of the pneumatic conveying device 12 is connected to the ash bin 13. The outlet of the F3 blower 8 is connected to the chimney 14. The A3 dust collector 6, the T3 desulfurization and denitrification device 7, and the F3 blower 8 are connected in a longitudinal straight - through manner; the A3 dust collector 6 is a two - stage dust removal device, the first stage is a cyclone dust collector, and the second stage is a cartridge dust collector; the T3 desulfurization and denitrification device 7 uses the ozone - oxidation desulfurization and denitrification method. Above the sintering material layer in the first calcination section, there is an M2 circulating smoke hood 10. The M2 circulating smoke hood 10 has two inlets. The first inlet of the M2 circulating smoke hood 10 is connected to the second flue gas pipeline 16. The second inlet of the M2 circulating smoke hood 10 is connected to an external gas source or an oxygen - increasing device through the TF2 gas regulating valve 17.

[0045] In the second stage of calcination, the exhaust mechanism includes a desulfurization and denitrification device 7 and a blower 8. The outlets of the air boxes 2 numbered M - P are respectively connected to the inlets of four mixing air ducts 4. The outlets of the four mixing air ducts 4 are connected to the inlet of the dust collector 6 numbered A4. The four mixing air ducts 4 and the dust collector 6 numbered A4 are connected in parallel in a longitudinal straight - through manner. The dust collector 6 numbered A4 has two outlets. The first outlet of the dust collector 6 numbered A4 is connected to the inlet of the desulfurization and denitrification device 7 numbered T4. The second outlet of the dust collector 6 numbered A4 is connected to the inlet of the pneumatic conveying device 12. The outlet of the desulfurization and denitrification device 7 numbered T4 is connected to the inlet of the blower 8 numbered F4. The outlet of the pneumatic conveying device 12 is connected to the ash bin 13. The outlet of the blower 8 numbered F3 is connected to the chimney 14. The dust collector 6 numbered A4, the desulfurization and denitrification device 7 numbered T4, and the blower 8 numbered F4 are connected in a longitudinal straight - through manner. The dust collector 6 numbered A4 is a two - stage dust removal device. The first stage is a multi - tube dust collector, and the second stage is a bag - type dust collector. The desulfurization and denitrification device 7 numbered T4 uses the zeolite catalytic combustion desulfurization and denitrification method. Above the sintered material layer in the second stage of calcination, there is a circulating smoke hood 10 numbered M3. The circulating smoke hood 10 numbered M3 has two inlets. The first inlet of the circulating smoke hood 10 numbered M3 is connected to the second flue gas pipeline 16. The second inlet of the circulating smoke hood 10 numbered M3 is connected to an external gas source or an oxygen - increasing device through the gas regulating valve 17 numbered TF3.

[0046] In the tail section, the exhaust mechanism includes a blower 8. The outlets of the air boxes 2 numbered Q - T are respectively connected to the inlets of four mixing air ducts 4. The outlets of the four mixing air ducts 4 are connected to the inlet of the dust collector 6 numbered A5. The four mixing air ducts 4 and the dust collector 6 numbered A5 are connected in parallel in a longitudinal straight - through manner. The dust collector 6 numbered A5 has two outlets. The first outlet of the dust collector 6 numbered A5 is connected to the inlet of the blower 8 numbered F5. The second outlet of the dust collector 6 numbered A5 is connected to the inlet of the pneumatic conveying device 12. The outlet of the pneumatic conveying device 12 is connected to the ash bin 13. The outlet of the blower 8 numbered F5 is connected to the flue gas mixing device 11 numbered H1 through the second flue gas pipeline 16. The outlet of the flue gas mixing device 11 numbered H1 is connected to the circulating smoke hoods 10 numbered M1, M2, and M3 through the second flue gas pipeline 16. Gas regulating valves 5 are respectively arranged between the flue gas mixing device 11 numbered H1 and the circulating smoke hoods 10 numbered M1, M2, and M3. The flue gas mixing device 11 numbered H1 is also connected to an external gas source or an oxygen - increasing device through the gas regulating valve 17 numbered TF6. Above the sintered material layer in the tail section, there is a circulating smoke hood 10 numbered M5. The circulating smoke hood 10 numbered M5 has two inlets. The outlet of the blower 8 numbered F1 in the ignition section is connected to the first inlet of the circulating smoke hood 10 numbered M5 in the tail section through the first flue gas pipeline 15. The second inlet of the circulating smoke hood 10 numbered M5 is connected to an external gas source or an oxygen - increasing device through the gas regulating valve 17 numbered TF5. The dust collector 6 numbered A5 and the blower 8 numbered F5 are connected in a longitudinal straight - through manner. The dust collector 6 numbered A5 is a two - stage dust removal device. The first stage is a cyclone dust collector, and the second stage is a bag - type dust collector.

[0047] In the cooling section, the exhaust mechanism includes a fan 8. The outlets of the air boxes 2 numbered U - W are respectively connected to the inlets of four mixing air ducts 4. The outlets of the four mixing air ducts 4 are connected to the inlet of a dust collector 6 numbered A6. The four mixing air ducts 4 and the dust collector 6 numbered A6 are connected in parallel in a longitudinal straight - through manner. The dust collector 6 numbered A6 has two outlets. The first outlet of the dust collector 6 numbered A6 is connected to the inlet of a fan 8 numbered F6, and the second outlet of the dust collector 6 numbered A6 is connected to the inlet of a pneumatic conveying device 12. The outlet of the pneumatic conveying device 12 is connected to a ash bin 13. The outlet of the fan 8 numbered F6 is connected to a flue gas mixing device 11 numbered H1 through a second flue gas pipeline 16. The dust collector 6 numbered A6 and the fan 8 numbered F6 are connected in a longitudinal straight - through manner. The dust collector 6 numbered A6 is a two - stage dust removal device. The first stage is a multi - tube dust collector, and the second stage is a cartridge dust collector.

[0048] It should be noted that by adjusting the sintering flue gas volume in the first flue gas pipeline 15 and the second flue gas pipeline 16, when the sintering flue gas circulates to above the sintering material layer in the circulation hood 10, the air pressure in the circulation hood 10 is maintained at a slightly negative pressure.

[0049] By adopting a dust removal device including a dust collector 6, a pneumatic conveying device 12 and an ash bin 13, while removing the dust in the flue gas, the dust collected in the dust collector 6 can also be sent to the ash bin 13 for centralized recovery and treatment, so as to achieve the unified discharge of dust and solve the problem of difficult dust recovery in decentralized dust removal at the same time.

[0050] The air box 2, the flue gas parameter detection device 3, the regulating valve 5, the dust collector 6, the desulfurization and denitrification device 7, the fan 8, the flue gas mixing device 11, the pneumatic conveying device 12 and the gas regulating valve 17 are all electrically connected to the control module 9, enabling intelligent regulation.

[0051] By transporting the flue gas in the ignition section to the tail section, the flue gas with a high CO content generated in the ignition section is transported to a high - temperature area and used as fuel for secondary combustion, so that the CO in the flue gas is fully oxidized into CO2. While reducing the flue gas pollutant emissions in the ignition section, the sintering flue gas in the ignition section is also quickly heated after heat exchange in the tail section. By transporting the sintering flue gas in the tail section and the cooling section to the sintering material layer in the pre - sintering section, the first calcination section and the second calcination section, the harmful components in the sintering flue gas enter the sintering material layer again to be thermally decomposed or transformed. Dioxins, nitrogen oxides, CO, etc. will be partially eliminated, and the generation of nitrogen oxides is inhibited, reducing the emissions of dust and sulfur dioxide. And the sintering flue gas generated by the sintering machine 1 is mainly concentrated in the ignition section, the tail section and the cooling section. By circulating the sintering flue gas in these three areas, the flue gas circulation utilization rate can be increased from the current 20% to 50%. At the same time, by transporting the sintering flue gas to the pre - sintering section, the first calcination section and the second calcination section for centralized desulfurization and denitrification treatment and centralized discharge, the project investment is also reduced and the operation cost is lowered, achieving the effect of energy conservation and emission reduction.

[0052] Example 3 This example provides an energy-saving and emission-reduction sintering system. Figure 3 As shown in the structural schematic diagram, the sintering machine 1 is divided into six regions along the traveling direction of the trolley, which are the ignition section, the pre-burning section, the first calcination section, the second calcination section, the tail section and the cooling section in sequence. There are 23 wind boxes 2 arranged below the trolley of the sintering machine 1. The A-D wind boxes 2 are the ignition section, the E-H wind boxes 2 are the pre-burning section, the I-L wind boxes 2 are the first calcination section, the M-P wind boxes 2 are the second calcination section, the Q-T wind boxes 2 are the tail section, and the U-W wind boxes 2 are the cooling section. Flue gas parameter detection devices 3 are arranged on all the A-W wind boxes 2. The air pressure and air volume of the A-W wind boxes 2 can be adjusted according to the performance data of the flue gas detected by the flue gas parameter detection devices 3. The flue gas parameter detection devices 3 are oxygen meters, temperature and humidity meters, pressure gauges, NO x sensors, SO2 sensors, CO sensors and CO2 sensors. The A-W wind boxes 2 are respectively connected to the dust collectors 6 in the corresponding regions through the mixing air ducts 4. A regulating valve 5 is arranged on the mixing air duct 4. The mixing air duct 4 and the corresponding dust collector 6 are connected in parallel in a longitudinal straight-through manner, which can reduce the system resistance.

[0053] In the ignition section, the exhaust mechanism includes a fan 8. The outlets of the A-D wind boxes 2 are respectively connected to the inlets of the four mixing air ducts 4. The outlets of the four mixing air ducts 4 are connected to the inlet of the A1 dust collector 6. The four mixing air ducts 4 and the A1 dust collector 6 are connected in parallel in a longitudinal straight-through manner. The A1 dust collector 6 has two outlets. The first outlet of the A1 dust collector 6 is connected to the inlet of the F1 fan 8. The second outlet of the A1 dust collector 6 is connected to the inlet of the pneumatic conveying device 12. The outlet of the pneumatic conveying device 12 is connected to the ash bin 13. The A1 dust collector 6 and the F1 fan 8 are connected in a longitudinal straight-through manner. The A1 dust collector 6 is a plastic plate dust collector.

[0054] In the pre - calcination section, the exhaust mechanism includes a desulfurization and denitrification device 7 and a blower 8. The outlets of the E - H air boxes 2 are respectively connected to the inlets of four mixing air ducts 4. The outlets of the four mixing air ducts 4 are connected to the inlet of the A2 dust collector 6. The four mixing air ducts 4 and the A2 dust collector 6 are connected in parallel horizontally. The A2 dust collector 6 has two outlets. The first outlet of the A2 dust collector 6 is connected to the inlet of the T2 desulfurization and denitrification device 7. The second outlet of the A2 dust collector 6 is connected to the inlet of the pneumatic conveying device 12. The outlet of the T2 desulfurization and denitrification device 7 is connected to the inlet of the F2 blower 8. The outlet of the pneumatic conveying device 12 is connected to the ash bin 13. The outlet of the F2 blower 8 is connected to the chimney 14. The A2 dust collector 6, the T2 desulfurization and denitrification device 7 and the F2 blower 8 are connected in parallel horizontally. The A2 dust collector 6 is a plastic - plate dust collector. The T2 desulfurization and denitrification device 7 uses the ozone - oxidation desulfurization and denitrification method. Above the sintering material layer in the pre - calcination section, there is an M1 circulating smoke hood 10. The M1 circulating smoke hood 10 has two inlets. The first inlet of the M1 circulating smoke hood 10 is connected to the second flue gas pipe 16. The second inlet of the M1 circulating smoke hood 10 is connected to an external gas source or an oxygen - increasing device through a TF1 gas regulating valve 17. By supplementing hot waste gas, oxygen or air through the gas regulating valve 17, a mixed sintering flue gas with an oxygen content of 19 - 20% is formed in the mixing air duct 4, which is more suitable for subsequent recycling.

[0055] In the first calcination section, the exhaust mechanism includes a desulfurization and denitrification device 7 and a blower 8. The outlets of the I - L air boxes 2 are respectively connected to the inlets of four mixing air ducts 4. The outlets of the four mixing air ducts 4 are connected to the inlet of the A3 dust collector 6. The four mixing air ducts 4 and the A3 dust collector 6 are connected in parallel longitudinally in a straight - through manner. The A3 dust collector 6 has two outlets. The first outlet of the A3 dust collector 6 is connected to the inlet of the T3 desulfurization and denitrification device 7. The second outlet of the A3 dust collector 6 is connected to the inlet of the pneumatic conveying device 12. The outlet of the T3 desulfurization and denitrification device 7 is connected to the inlet of the F3 blower 8. The outlet of the pneumatic conveying device 12 is connected to the ash bin 13. The outlet of the F3 blower 8 is connected to the chimney 14. The A3 dust collector 6, the T3 desulfurization and denitrification device 7 and the F3 blower 8 are connected in a straight - through longitudinal manner. The A3 dust collector 6 is a two - stage dust - removal device. The first stage is a cyclone dust collector, and the second stage is a cartridge dust collector; the T3 desulfurization and denitrification device 7 uses the ozone - oxidation desulfurization and denitrification method. Above the sintering material layer in the first calcination section, there is an M2 circulating smoke hood 10. The M2 circulating smoke hood 10 has two inlets. The first inlet of the M2 circulating smoke hood 10 is connected to the second flue gas pipe 16. The second inlet of the M2 circulating smoke hood 10 is connected to an external gas source or an oxygen - increasing device through a TF2 gas regulating valve 17.

[0056] In the second stage of calcination, the exhaust gas mechanism includes a desulfurization and denitrification device 7 and a blower 8. The outlets of the air boxes 2 numbered M - P are respectively connected to the inlets of four mixing air ducts 4. The outlets of the four mixing air ducts 4 are connected to the inlet of the dust collector 6 numbered A4. The four mixing air ducts 4 and the dust collector 6 numbered A4 are connected in parallel in a longitudinal straight - through manner. The dust collector 6 numbered A4 has two outlets. The first outlet of the dust collector 6 numbered A4 is connected to the inlet of the desulfurization and denitrification device 7 numbered T4. The second outlet of the dust collector 6 numbered A4 is connected to the inlet of the pneumatic conveying device 12. The outlet of the desulfurization and denitrification device 7 numbered T4 is connected to the inlet of the blower 8 numbered F4. The outlet of the pneumatic conveying device 12 is connected to the ash bunker 13. The outlet of the blower 8 numbered F3 is connected to the chimney 14. The dust collector 6 numbered A4, the desulfurization and denitrification device 7 numbered T4, and the blower 8 numbered F4 are connected in a longitudinal straight - through manner. The dust collector 6 numbered A4 is a two - stage dust removal device. The first stage is a multi - tube dust collector, and the second stage is a bag - type dust collector. The desulfurization and denitrification device 7 numbered T4 uses the zeolite catalytic combustion desulfurization and denitrification method. Above the sintering material layer in the second stage of calcination, there is a circulating smoke hood 10 numbered M3. The circulating smoke hood 10 numbered M3 has two inlets. The first inlet of the circulating smoke hood 10 numbered M3 is connected to the second flue gas pipeline 16. The second inlet of the circulating smoke hood 10 numbered M3 is connected to an external gas source or an oxygen - increasing device through a gas regulating valve 17 numbered TF3.

[0057] In the tail section, the exhaust mechanism includes a blower 8. The outlets of the air boxes 2 numbered Q - T are respectively connected to the inlets of four mixing air ducts 4. The outlets of the four mixing air ducts 4 are connected to the inlet of a dust collector 6 numbered A5. The four mixing air ducts 4 and the dust collector 6 numbered A5 are connected in parallel in a longitudinal straight - through manner. The dust collector 6 numbered A5 has two outlets. The first outlet of the dust collector 6 numbered A5 is connected to the inlet of a blower 8 numbered F5. The second outlet of the dust collector 6 numbered A5 is connected to the inlet of a pneumatic conveying device 12. The outlet of the pneumatic conveying device 12 is connected to a ash bin 13. The outlet of the blower 8 numbered F5 is connected to a flue gas mixing device 11 numbered H1 through a second flue gas pipeline 16. The outlet of the flue gas mixing device 11 numbered H1 is connected to the circulating flue gas hoods 10 numbered M1, M2, and M3 through a second flue gas pipeline 16. Control valves 5 are respectively arranged between the flue gas mixing device 11 numbered H1 and the circulating flue gas hoods 10 numbered M1, M2, and M3. The flue gas mixing device 11 numbered H1 is also connected to an external air source or an oxygen - increasing device through a gas control valve 17 numbered TF6. Above the sintered material layer in the tail section, there is a circulating flue gas hood 10 numbered M5. The circulating flue gas hood 10 numbered M5 has two inlets. The outlet of the blower 8 numbered F1 in the ignition section is connected to the inlet of a flue gas mixing device 11 numbered H2 through a first flue gas pipeline 15. The outlet of the flue gas mixing device 11 numbered H2 is connected to the inlet of the circulating flue gas hood 10 numbered M5 in the tail section. The flue gas mixing device 11 numbered H2 is also connected to an external air source or an oxygen - increasing device through a gas control valve 17 numbered TF7. The dust collector 6 numbered A5 and the blower 8 numbered F5 are connected in a longitudinal straight - through manner; the dust collector 6 numbered A5 is a two - stage dust removal device. The first stage is a cyclone dust collector, and the second stage is a bag - type dust collector.

[0058] In the cooling section, the outlets of the air boxes 2 numbered U - W are respectively connected to the inlets of four mixing air ducts 4. The outlets of the four mixing air ducts 4 are connected to the inlet of a dust collector 6 numbered A6. The four mixing air ducts 4 and the dust collector 6 numbered A6 are connected in parallel in a longitudinal straight - through manner. The dust collector 6 numbered A6 has two outlets. The first outlet of the dust collector 6 numbered A6 is connected to the inlet of a blower 8 numbered F6. The second outlet of the dust collector 6 numbered A6 is connected to the inlet of a pneumatic conveying device 12. The outlet of the pneumatic conveying device 12 is connected to a ash bin 13. The outlet of the blower 8 numbered F6 is connected to a flue gas mixing device 11 numbered H1 through a second flue gas pipeline 16. Above the sintered material layer in the cooling section, there is a circulating flue gas hood 10 numbered M4. The outlet of the flue gas mixing device 11 numbered H2 is also connected to the circulating flue gas hood 10 numbered M4 in the cooling section through a first flue gas pipeline 15 and a control valve 5. The dust collector 6 numbered A6 and the blower 8 numbered F6 are connected in a longitudinal straight - through manner; the dust collector 6 numbered A6 is a two - stage dust removal device. The first stage is a multi - tube dust collector, and the second stage is a cartridge dust collector.

[0059] It should be noted that by adjusting the sintering flue gas volume in the first flue gas pipeline 15 and the second flue gas pipeline 16, when the sintering flue gas is circulated above the sintering material layer in the circulating hood 10, the air pressure in the circulating hood 10 is maintained at a slightly negative pressure.

[0060] By adopting a dust removal device including a dust collector 6, a pneumatic conveying device 12 and a dust bin 13, while removing the dust in the flue gas, the dust collected in the dust collector 6 can also be sent to the dust bin 13 for centralized recovery and treatment, so as to realize the unified discharge of dust and solve the problem of difficult dust recovery in decentralized dust removal at the same time.

[0061] The wind box 2, the flue gas parameter detection device 3, the regulating valve 5, the dust collector 6, the desulfurization and denitrification device 7, the fan 8, the flue gas mixing device 11, the pneumatic conveying device 12 and the gas regulating valve 17 are electrically connected to the control module 9, and intelligent regulation can be realized.

[0062] By transporting the flue gas in the ignition section to the tail section and the cooling section, the flue gas with a high CO content generated in the ignition section is transported to the high-temperature area and burned as fuel for secondary combustion, so that the CO in the flue gas is fully oxidized into CO2. While reducing the pollutant emissions of the flue gas in the ignition section, the sintering flue gas in the ignition section is quickly heated after heat exchange in the cooling section and the tail section; by transporting the sintering flue gas in the tail section and the cooling section to the sintering material layer in the pre-burning section, the first calcination section and the second calcination section, the harmful components in the sintering flue gas enter the sintering material layer again to be thermally decomposed or transformed, and dioxins, nitrogen oxides, CO, etc. will be partially eliminated, and the generation of nitrogen oxides will be inhibited, reducing the emissions of dust and sulfur dioxide; and the sintering flue gas generated by the sintering machine 1 is mainly concentrated in the ignition section, the tail section and the cooling section. By circulating the sintering flue gas in these three regions, the flue gas circulation utilization rate can be increased from the current 20% to 50%; at the same time, by transporting the sintering flue gas to the pre-burning section, the first calcination section and the second calcination section for centralized desulfurization and denitrification treatment and centralized discharge, the project investment is also reduced and the operation cost is lowered, achieving the effect of energy conservation and emission reduction.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; in particular, the division of each area of the sintering machine can be set according to the area of the sintering machine, the number of wind boxes can also be adjusted according to requirements, and the dust removal, desulfurization and denitration devices in each area can also be selectively changed according to the flue gas characteristics based on the mature technologies in the industry. The double flue gas cycle can also be adjusted and selected according to the area of the sintering machine, the number of wind boxes, and the flue gas characteristics; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flue gas double-cycle sintering system, characterized in that, It includes a sintering machine (1), a first flue gas pipeline (15) and a second flue gas pipeline (16). The sintering machine (1) is divided into multiple zones along the traveling direction of the trolley. The multiple zones are sequentially the ignition zone, the pre-sintering zone, the first calcination zone, the second calcination zone, the tail section and the cooling zone along the traveling direction of the trolley. The sintering flue gas generated in the ignition zone enters the first flue gas pipeline (15), and the sintering flue gas generated in the tail section and the cooling zone enters the second flue gas pipeline (16). The outlet of the first flue gas pipeline (15) is arranged on the sintered material layer in at least one zone of the tail section and the cooling zone to convey the sintering flue gas generated in the ignition zone and form a first cycle. The outlet of the second flue gas pipeline (16) is arranged on the sintered material layer in the pre-sintering zone, the first calcination zone and the second calcination zone to convey the sintering flue gas generated in the tail section and the cooling zone and form a second cycle.

2. The flue gas double-cycle sintering system according to claim 1, characterized in that A plurality of wind boxes (2) are arranged in each zone. The outlet of each wind box (2) is communicated with a regulating valve (5). All the corresponding regulating valves (5) in each zone are jointly communicated with a dust removal device. The outlet of the dust removal device in each zone is communicated with an exhaust mechanism. In the ignition zone, the outlet of the exhaust mechanism is communicated with the first flue gas pipeline (15). In the pre-sintering zone, the first calcination zone and the second calcination zone, the outlet of the exhaust mechanism is communicated with a chimney. In the tail section and the cooling zone, the outlet of the exhaust mechanism is communicated with the second flue gas pipeline (16).

3. The flue gas double-circulation sintering system according to claim 2, wherein, It further includes a flue gas mixing device (11) and a plurality of circulating flue gas hoods (10) arranged above the sintered material layer. The flue gas mixing device (11) is arranged in the middle of the second flue gas pipeline (16). The flue gas mixing device (11) has two inlets. The first inlet and the outlet of the flue gas mixing device (11) are communicated with the second flue gas pipeline (16). The inlets of all the circulating flue gas hoods (10) are respectively communicated with the first flue gas pipeline (15) and the second flue gas pipeline (16). A ventilation opening is arranged on the circulating flue gas hood (10). The second inlet of the flue gas mixing device (11) and the ventilation openings on each circulating flue gas hood (10) are all communicated with a gas regulating valve (17). The gas regulating valve (17) is communicated with an external gas source or an oxygen enrichment device.

4. The flue gas double circulation sintering system according to claim 3, wherein, Flue gas parameter detection devices (3) are arranged on the outlet pipeline of the wind box (2), the first flue gas pipeline (15) and the second flue gas pipeline (16) to detect the performance parameters of the sintering flue gas.

5. The flue gas double-cycle sintering system according to claim 4, characterized in that, The flue gas parameter detection device (3) includes at least one of an oxygen meter, a temperature and humidity meter, a pressure gauge, a NO x sensor, an SO2 sensor, a CO sensor, and a CO2 sensor.

6. The flue gas double circulation sintering system according to claim 5, characterized in that, The dust removal device includes a dust collector (6), a pneumatic conveying device (12) and a ash bin (13). The inlet of the dust collector (6) is communicated with the outlet of the regulating valve (5). The dust collector (6) has two outlets. The first outlet of the dust collector (6) is communicated with the inlet of the exhaust mechanism. The second outlet of the dust collector (6) is communicated with the ash bin (13) through the pneumatic conveying device (12).

7. The flue gas double-circulation sintering system according to claim 6, characterized in that, In the pre-firing section, the first calcination section, and the second calcination section, the exhaust mechanism includes a desulfurization and denitration device (7) and a fan (8). The outlet of the desulfurization and denitration device (7) is communicated with the inlet of the fan (8), and the inlet of the desulfurization and denitration device (7) is communicated with the outlet of the dust collector (6).

8. The flue gas double-cycle sintering system according to claim 6, wherein In the ignition section, the tail section, and the cooling section, the exhaust mechanism includes a fan (8). The inlet of the fan (8) is communicated with the outlet of the dust collector (6).

9. The flue gas double-circulation sintering system according to claim 7 or 8, characterized in that The air box (2), the flue gas parameter detection device (3), the regulating valve (5), the dust removal device, the circulating smoke hood (10), the exhaust mechanism, and the flue gas mixing device (11) are electrically connected to a control module (9).

10. Application of the double-cycle sintering system for flue gas as claimed in claim 1 in iron and steel smelting.

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