Sinter hot air and flue gas circulation system

Abstract

The application discloses a sintering hot air and flue gas circulating system, which comprises a trolley, a ring cooling machine and a heat recovery device; a firing hood, a flue gas hood, a medium temperature hood and a low temperature hood are sequentially arranged on the upper portion of the trolley from the head to the tail direction; a tail hood is arranged at the material falling position of the tail of the trolley; the ring cooling four-stage fan extracts air, and the ring cooling four-stage hot air outlet is connected to the low temperature hood; the ring cooling three-stage fan extracts air, and the ring cooling three-stage hot air outlet is connected to the firing hood and the medium temperature hood; the ring cooling one-stage and ring cooling two-stage outlets are connected to the ring cooling one-stage fan and the ring cooling two-stage fan through a pipeline; the pipeline is provided with the heat recovery device and the fan; the tail hood is connected to the outlet pipeline of the second fan; the low temperature hood bottom air bellow collected flue gas is connected to the flue gas hood; the firing hood, the flue gas hood and the medium temperature hood bottom air bellow collected flue gas are connected to the chimney. The application fully utilizes the characteristics of hot air and flue gas of each stage, improves the sintering yield, increases the sintering output and reduces the operation energy consumption.

Description

Technical Field

[0001] This invention relates to the field of energy conservation and emission reduction technology in the sintering process of the iron and steel metallurgical industry, specifically to a sintering hot air and flue gas circulation system. Background Technology

[0002] Sintering is an important process in ironmaking in the iron and steel metallurgical industry. The energy consumption of the sintering process accounts for about 13% of the total energy consumption of iron and steel production. Of the energy consumption in sintering production, solid fuel consumption accounts for 75% to 80% of the total energy consumption of the sintering process, electricity consumption accounts for 13% to 20%, and ignition fuel consumption accounts for 5% to 10%. Therefore, energy conservation and consumption reduction in sintering has become an important part of energy conservation and emission reduction for iron and steel enterprises.

[0003] In conventional sintering processes, there are multiple exhaust outlets, with exhaust gas temperatures ranging from 70℃ to 250℃. The sensible heat in the exhaust gas is not utilized and is directly emitted. For example, the hot air discharged from the third and fourth stages of the annular cooling system has a temperature of 70℃ to 250℃ and is directly emitted into the atmosphere; the exhaust gas temperature from the tail hood is 100℃ to 250℃, and after dust collection by a bag filter, it is directly emitted into the atmosphere, resulting in energy waste. Summary of the Invention

[0004] To address the problems mentioned above in the background art, the present invention provides a sintering hot air and flue gas circulation system.

[0005] A sintering hot air and flue gas circulation system includes a trolley, an annular cooler, and a heat recovery device; the upper part of the trolley is provided with an ignition hood, a flue gas hood, a medium-temperature hood, and a low-temperature hood in sequence from the head to the tail; a tail hood is provided at the material discharge point of the trolley; the annular cooler includes an annular cooling section 1, an annular cooling section 2, an annular cooling section 3, and an annular cooling section 4.

[0006] Air is drawn from the inlet of the four-stage annular cooling fan, and the hot air outlet of the four-stage annular cooling fan is connected to the low-temperature hood through a second pipe, on which a second fan is installed.

[0007] The inlet of the three-stage annular cooling fan draws air, and the hot air outlet of the three-stage annular cooling fan is connected to the ignition hood and the medium-temperature hood through a third pipe. A third fan is installed on the third pipe.

[0008] The outlets of the first and second annular cooling sections are combined and connected to the inlet of the first and second annular cooling section fans via a first pipeline. The first pipeline is equipped with a first heat recovery device and a first fan.

[0009] The tail cover is connected to the outlet pipe of the second fan through a fourth pipe, and the fourth pipe is provided with a second dust removal device and a fifth fan in sequence from the direction of flue gas flow.

[0010] The flue gas collected by the bottom air box of the low temperature hood is connected to the flue gas hood through the fifth pipe. The fifth pipe is provided with a first dust removal device, a combustion heating device, a second heat recovery device and a fourth fan in sequence from the direction of flue gas flow.

[0011] The flue gas collected by the bottom air box of the ignition hood, flue gas hood and intermediate temperature hood is connected to the chimney inlet through the sixth pipe, and the sixth pipe is equipped with a flue gas treatment device.

[0012] Based on the above scheme and as a preferred embodiment of the above scheme: the ignition cover, the smoke cover, the medium temperature cover and the low temperature cover are all non-completely sealed covers, and each is equipped with a temperature detector, a pressure detector, a hot air inlet device and an air inlet device.

[0013] The tail cover is a completely sealed cover.

[0014] Based on the above scheme and as a preferred embodiment of the above scheme: the fume hood is also equipped with an automatic oxygen filling device.

[0015] Based on the above scheme and as a preferred embodiment of the above scheme: the flue gas treatment device includes a third dust removal device, a sixth fan, a desulfurization device, a fourth dust removal device, a denitrification device, and a seventh fan connected in series.

[0016] Based on the above scheme and as a preferred embodiment of the above scheme: the third dust removal device includes any one of electrostatic precipitator, bag filter, multi-tube dust collector and cyclone dust collector.

[0017] Based on the above scheme and as a preferred embodiment of the above scheme: the desulfurization device is a dry desulfurization device, a semi-dry desulfurization device, or a wet desulfurization device;

[0018] When the desulfurization device is a wet desulfurization device, the fourth dust removal device is a tube bundle demister or a wet electrostatic precipitator; a condensation device and a water collection and dust removal device can be installed after the fourth dust removal device. The condensate collected by the water collection and dust removal device is treated and used entirely as process water for the desulfurization system. The desulfurization wastewater generated by wet desulfurization is treated by a wastewater treatment device, and more than 90% of the wastewater is reused in the desulfurization system or production system, while the remaining wastewater is discharged.

[0019] When the desulfurization device is a dry desulfurization device or a semi-dry desulfurization device, the fourth dust removal device is a bag filter or an electrostatic precipitator-bag filter combination dust collector.

[0020] Based on the above scheme and as a preferred embodiment of the above scheme: the denitrification device can be a condensation device, a water collection and dust removal device, a heating device, a GGH heat exchanger and a hot air furnace heating device with SCR denitrification or an oxidation denitrification method set before the desulfurization device.

[0021] Based on the above scheme and as a preferred embodiment of the above scheme: the temperature resistance range of the sixth and seventh fans is 100℃~200℃.

[0022] Based on the above scheme and as a preferred embodiment of the above scheme: the first dust removal device is a dry dust collector with a temperature resistance of 300℃~400℃, which is a multi-tube dust collector or a cyclone dust collector.

[0023] The second dust removal device is a dry dust collector with a temperature resistance of 100℃~200℃, which can be a multi-tube dust collector, a cyclone dust collector, an electrostatic dust collector, or a bag dust collector.

[0024] The temperature resistance range of the first fan, the second fan, the fourth fan, and the fifth fan is 100℃~200℃;

[0025] The temperature range of the third fan is 200℃~300℃.

[0026] Based on the above scheme and as a preferred embodiment of the above scheme: the first heat recovery device and the second heat recovery device are used to generate electricity or produce steam or hot water.

[0027] By employing the above technical solutions, this invention has the following advantages and positive effects compared with the prior art:

[0028] 1. This invention circulates hot air and flue gas to the sinter layer, which increases the temperature of the sinter layer, reduces the cooling rate of the mixture, increases the liquid phase layer of the mixture, improves the strength of the sinter, and improves the overall yield of sintering.

[0029] 2. This invention increases the roasting speed of sintered ore and reduces the roasting time by increasing the air inlet temperature during the roasting process. Therefore, the sintering output can be increased by increasing the travel speed of the sintering machine trolley and increasing the thickness of the sintering material layer.

[0030] 3. This invention reuses the medium and low temperature hot air from the fourth stage of the annular cooling system to the low temperature hood of the sintering machine, reuses the medium temperature hot air from the third stage of the annular cooling system to the ignition hood and medium temperature hood of the sintering machine, and recovers the heat from the high temperature hot air from the first and second stages of the annular cooling system through a heat recovery device; and reuses the high temperature flue gas from the tail of the trolley to the flue gas hood of the sintering machine, thus making full use of the heat generated during the production process and reducing production energy consumption. Attached Figure Description

[0031] The above and other features and advantages of the present invention will become clearer from the following detailed description, taken in conjunction with the accompanying drawings, wherein:

[0032] Figure 1 This is a schematic diagram of the structure of a sintering hot air and flue gas circulation system according to the present invention.

[0033] In the diagram: 1. First fan; 2. First heat recovery device; 3. Circulating cooler; 4. Second fan; 5. Third fan; 6. Tail cover; 7. Trolley; 8. Low temperature cover; 9. Medium temperature cover; 10. Flue gas hood; 11. Ignition cover; 12. Fourth fan; 13. Afterburner heating device; 14. Second heat recovery device; 15. First dust removal device; 16. Second dust removal device; 17. Fifth fan; 18. Third dust removal device; 19. Sixth fan; 20. Primary desulfurization tower; 21. Secondary desulfurization tower; 22. Fourth dust removal device; 23. Condenser. 24. Water collection and dust removal device; 25. Heating device; 26. GGH heat exchanger; 27. Denitrification device; 28. Seventh fan; 29. ​​Chimney; 301. Circular cooling section 1; 302. Circular cooling section 2; 303. Circular cooling section 3; 304. Circular cooling section 4; 305. Circular cooling section 1 fan; 306. Circular cooling section 4 fan; 307. Circular cooling section 2 fan; 308. Circular cooling section 3 fan; 401. First pipeline; 402. Second pipeline; 403. Third pipeline; 404. Fourth pipeline; 405. Fifth pipeline; 406. Sixth pipeline. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures, or the orientation or positional relationship commonly used when the product is in use. They are merely simplified descriptions for ease of description and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0036] See Figure 1As shown, a sintering hot air and flue gas circulation system includes a trolley 7, an annular cooler 3, and a heat recovery device 2. The upper part of the trolley 7 is sequentially equipped with an ignition hood 11, a flue gas hood 10, a medium-temperature hood 9, and a low-temperature hood 8 from the head to the tail. A tail cover 6 is installed at the material discharge point of the trolley 7. The annular cooler 3 includes an annular cooling section 301, an annular cooling section 302, an annular cooling section 303, and an annular cooling section 304. Air is drawn from the inlet of the fan 306 in the annular cooling section 304, and the hot air outlet of the annular cooling section 304 is connected to the low-temperature hood 8 via a second pipe 402, on which a second fan 4 is installed. Air is drawn from the inlet of the fan 308 in the annular cooling section 303, and the hot air outlet of the annular cooling section 303 is connected to the ignition hood 11 and the medium-temperature hood 9 via a third pipe 403, on which a third fan 5 is installed. The annular cooling section 301 and the annular cooling section 302... After the flue gas is collected at the outlet, it is connected to the inlet of the first-stage annular cooling fan 305 and the second-stage annular cooling fan 307 via the first pipe 401. The first pipe 401 is equipped with a first heat recovery device 2 and a first fan 1. The tail cover 6 is connected to the outlet pipe of the second fan 4 via the fourth pipe 404. The fourth pipe 404 is equipped with a second dust removal device 16 and a fifth fan 17 in sequence from the flue gas flow direction. The bottom bellows of the low-temperature cover 8 collects the flue gas and connects it to the flue gas cover 10 via the fifth pipe 405. The fifth pipe 405 is equipped with a first dust removal device 15, a combustion heating device 13, a second heat recovery device 14, and a fourth fan 12 in sequence from the flue gas flow direction. The bottom bellows of the ignition cover 11, the flue gas cover 10, and the medium-temperature cover 9 collect the flue gas and connect it to the inlet of the chimney 29 via the sixth pipe 406. The sixth pipe 406 is equipped with a flue gas treatment device. In this embodiment, the first heat recovery device 2 and the second heat recovery device 14 are used to generate electricity or produce steam or hot water.

[0037] In one specific example of this application, the temperature resistance range of the first fan 1, the second fan 4, the fourth fan 12, and the fifth fan 17 is 100℃~200℃; the temperature resistance range of the third fan 5 is 200℃~300℃.

[0038] In one specific example of this application, the ignition hood 11, the flue hood 10, the intermediate temperature hood 9, and the low temperature hood 8 are all non-fully sealed hoods, and each is equipped with a temperature detector, a pressure detector, a hot air inlet device, and an air inlet device; the tail cover 6 is a fully sealed hood. Furthermore, the flue hood 10 is also equipped with an automatic oxygen filling device.

[0039] In one specific example of this application, the flue gas treatment device includes a third dust removal device 18, a sixth fan 19, a desulfurization device, a fourth dust removal device 22, a denitrification device 27, and a seventh fan 28 connected in series. In this embodiment, the temperature resistance range of the sixth fan 19 and the seventh fan 28 is 100℃~200℃.

[0040] In one specific example of this application, the first dust removal device 15 is a dry dust collector with a temperature resistance of 300℃ to 400℃, which can be a multi-tube dust collector or a cyclone dust collector; the second dust removal device 16 is a dry dust collector with a temperature resistance of 100℃ to 200℃, which can be a multi-tube dust collector, a cyclone dust collector, an electrostatic precipitator, or a bag filter dust collector; and the third dust removal device 18 is an electrostatic precipitator, a bag filter dust collector, a multi-tube dust collector, or a cyclone dust collector with a temperature resistance of 100℃ to 200℃. It should be noted that the above examples are specific examples of the first dust removal device 15, the second dust removal device 16, and the third dust removal device 18. This application does not limit the specific structure of the first dust removal device 15, the second dust removal device 16, and the third dust removal device 18, and other dust collectors are also within the protection scope of this application.

[0041] In one specific example of this application, the desulfurization device is a dry desulfurization device, a semi-dry desulfurization device, or a wet desulfurization device. When the desulfurization device is a wet desulfurization device, the fourth dust removal device 22 is a tube bundle demister or a wet electrostatic precipitator. A condensation device 23 and a water collection and dust removal device 24 can be installed after the fourth dust removal device 22. The condensate collected by the water collection and dust removal device 24 is treated and used entirely as process water for the desulfurization system. The desulfurization wastewater generated by wet desulfurization is treated by a wastewater treatment device, and more than 90% of the wastewater is reused in the desulfurization system or production system, while the remaining wastewater is discharged. Specifically, when the desulfurization device is a wet desulfurization device, the desulfurization device includes a primary desulfurization tower 20 and a secondary desulfurization tower 21. A wet electrostatic precipitator is installed at the top of the secondary desulfurization tower 21. For high-concentration SO2 flue gas, it can reduce the SO2 concentration in the flue gas from 4000 to 20000 mg / Nm³. 3 At that time, the concentration decreased to 20 mg / Nm after treatment. 3 The desulfurization efficiency can reach 99.99%; when the SO2 concentration in the flue gas is ≤4000mg / Nm³. 3 When necessary, a primary desulfurization tower 18, a dry desulfurization device, or a semi-dry desulfurization device can be used to achieve ultra-low emission requirements.

[0042] In a specific example of this application, a lime-gypsum wet desulfurization process is used, with lime as the desulfurizing agent. The SO2 in the flue gas reacts with the desulfurizing agent as follows:

[0043] Ca(OH)₂ + SO₂ → CaSO₃

[0044] CaSO3 + SO2 + H2O → Ca(HSO3)2

[0045] Ca(OH)2+Ca(HSO3)2→2CaSO3+H2O

[0046] CaSO3 + 1 / 2O2 → CaSO4

[0047] In this embodiment, the desulfurization agent for the wet desulfurization process can be alkaline substances such as MgO, CaO, NaOH, Na2CO3, ammonia water, and carbide slag; the supporting fourth dust removal device 22 after wet desulfurization can be a wet electrostatic precipitator, a tube bundle dust collector, or a water washing dust removal device.

[0048] In another embodiment of the present application, when the desulfurization device is a dry desulfurization device or a semi-dry desulfurization device, the fourth dust removal device 22 is a bag filter or an electric bag composite dust collector; it should be noted that the above examples are specific examples of the fourth dust removal device 22, and the present application does not limit the specific structure of the fourth dust removal device 22, and other dust collectors are also within the protection scope of the present application.

[0049] In this embodiment, the condensation device 23, the water collection and fine dust removal device 24, and the temperature raising device 25 can be adjusted; in actual supporting settings, the temperature raising device 25 can be not set, and only the condensation device 23 and the water collection and fine dust removal device 24 are retained; or if the desulfurization process is a dry desulfurization process or a semi-dry desulfurization process, the fourth dust removal device 22 is changed to a bag filter, and the condensation device 23, the water collection and fine dust removal device 24, and the temperature raising device 25 are no longer set.

[0050] The condensed water collected by the water collection and fine dust removal device 24 is all used as process water for the desulfurization system after treatment. The desulfurization wastewater generated by wet desulfurization, after passing through the wastewater treatment device, more than 90% of the wastewater is recycled to the desulfurization system or the production system, and the remaining wastewater is discharged.

[0051] A specific example of the present application, the denitration device 27 includes a hot blast stove temperature raising device, an ammonia water evaporation and mixing device, an ammonia injection device, a reactor rectification device, and a catalyst ash cleaning device, and the reaction temperature of the denitration catalyst is 240°C to 300°C. It should be noted that in the present application, the denitration device 27 is the SCR denitration supporting the condensation device 23, the water collection and fine dust removal device 24, the temperature raising device 25, the GGH heat exchanger 26, the hot blast stove temperature raising, or the oxidation method denitration device 27 arranged in front of the desulfurization device. In this embodiment, the condensation device 23 is a condenser, the water collection and fine dust removal device 24 is a water collection and fine dust collector, and the temperature raising device 25 is a temperature raiser.

[0052] The following reactions occur in the denitration reactor:

[0053] 4NO + 4NH3 + O2 → 4N2 + 6H2O

[0054] 6NO + 4NH3 → 5N2 + 6H2O

[0055] 6NO2 + 8NH3 → 7N2 + 12H2O

[0056] 2NO2 + 4NH3 + O2 → 3N2 + 6H2O

[0057] The denitrification agent used in the denitrification unit 27 is ammonia, urea, organic polymer denitrification agent or other amino substances. The amino substances decompose into ammonia gas, which acts as a reducing agent to undergo SCR reaction, converting NOx into pollution-free N2 emissions.

[0058] Those skilled in the art will understand that the present invention can be implemented in many other specific forms without departing from its spirit or scope. Although embodiments of the invention have been described, it should be understood that the invention is not limited to these embodiments, and those skilled in the art can make changes and modifications within the spirit and scope of the invention as defined in the appended claims.

Claims

1. A sintering hot air and flue gas circulation system comprising a trolley, a ring cooler and a heat recovery device; the trolley is provided with a firing hood, a flue gas hood, a medium temperature hood and a low temperature hood in sequence from the head to the tail; a tail hood is arranged at the material discharging position of the tail of the trolley; the ring cooler comprises a ring cooling first stage, a ring cooling second stage, a ring cooling third stage and a ring cooling fourth stage; characterized in that, the inlet of the fan of the ring cooling fourth stage draws air, the hot air outlet of the ring cooling fourth stage is connected to the low temperature hood through a second pipeline, and a second fan is arranged on the second pipeline; the inlet of the fan of the ring cooling third stage draws air, the hot air outlet of the ring cooling third stage is connected to the firing hood and the medium temperature hood through a third pipeline, and a third fan is arranged on the third pipeline; the outlets of the ring cooling first stage and the ring cooling second stage are connected to the inlets of the fans of the ring cooling first stage and the ring cooling second stage through a first pipeline, and a first heat recovery device and a first fan are arranged on the first pipeline; the tail hood is connected to the outlet pipeline of the second fan through a fourth pipeline, and a second dust removal device and a fifth fan are arranged on the fourth pipeline in sequence from the flue gas flow direction; the flue gas collected by the wind boxes at the bottom of the low temperature hood is connected to the flue gas hood through a fifth pipeline, and a first dust removal device, a combustion supplementing and temperature raising device, a second heat recovery device and a fourth fan are arranged on the fifth pipeline in sequence from the flue gas flow direction; the flue gas collected by the wind boxes at the bottom of the firing hood, the flue gas hood and the medium temperature hood is connected to the inlet of the chimney through a sixth pipeline, and a flue gas treatment device is arranged on the sixth pipeline; the firing hood, the flue gas hood, the medium temperature hood and the low temperature hood are all non-hermetic hoods, and are all provided with a temperature detector, a pressure detector, a hot air inlet device and an air inlet device; the tail hood is a hermetic hood.

2. The sintering hot air and flue gas circulation system according to claim 1, characterized in that, An automatic oxygen charging device is further arranged on the flue gas hood.

3. The sintering hot air and flue gas circulation system according to claim 1, characterized in that, The flue gas treatment device comprises a third dust removal device, a sixth fan, a desulfurization device, a fourth dust removal device, a denitration device and a seventh fan connected in sequence.

4. The sintering hot air and flue gas circulation system according to claim 3, characterized in that, The third dust removal device comprises any one of an electrostatic precipitator, a bag dust collector, a multi-tube dust collector and a cyclone dust collector.

5. The sintering hot air and flue gas circulation system according to claim 3, characterized in that, The desulfurization device is a dry desulfurization device, a semi-dry desulfurization device or a wet desulfurization device; when the desulfurization device is a wet desulfurization device, the fourth dust removal device is a pipe bundle mist eliminator or a wet electrostatic precipitator; a condensing device and a water collection and precision dust removal device can be arranged after the fourth dust removal device, the condensate collected by the water collection and precision dust removal device is treated and then all used as process water of the desulfurization system, more than 90% of the desulfurization wastewater generated by the wet desulfurization is reused to the desulfurization system or the production system, and the rest is discharged; when the desulfurization device is a dry desulfurization device or a semi-dry desulfurization device, the fourth dust removal device is a bag dust collector or an electric bag composite dust collector.

6. The sintering hot air and flue gas circulation system according to claim 3, characterized in that, The denitration device is a condensing device, a water collection and precision dust removal device, a temperature raising device, a GGH heat exchanger and a hot blast stove temperature raising device matched with an SCR denitration device or an oxidation method denitration device arranged before the desulfurization device.

7. The sintering hot air and flue gas circulation system according to claim 4, characterized in that, The temperature resistance range of the sixth fan and the seventh fan is 100℃-200℃.

8. The sintering hot air and flue gas circulation system according to claim 1, characterized in that, The first dust removal device is a dry dust remover with temperature resistance of 300-400 DEG C, and is a multi-tube dust remover or a cyclone dust remover; The second dust removal device is a dry dust remover with temperature resistance of 100-200 DEG C, and is a multi-tube dust remover or a cyclone dust remover or an electrostatic dust remover or a bag dust remover; The temperature resistance range of the first fan, the second fan, the fourth fan and the fifth fan is 100-200 DEG C; The temperature resistance range of the third fan is 200-300 DEG C.

9. The sintering hot air and flue gas circulation system according to claim 1, characterized in that: The first heat recovery device and the second heat recovery device are used for power generation or steam and hot water production.

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