System for regulating and controlling quality of circulating flue gas

Abstract

The utility model provides a system for regulating and controlling the quality of circulating flue gas. The system comprises a sintering machine, a vertical cooling device and an oxygenating device, and a first flue and a second flue are arranged below the sintering machine. The head air bellow and the middle air bellow are communicated with the bottom of the vertical cooling device through the first flue, and the oxygenating device is communicated with the first flue or the bottom of the vertical cooling device. And the tail air box is communicated with the second flue. According to the system for regulating and controlling the quality of the circulating flue gas, the sintering flue gas of the head air bellow and the middle air bellow is coupled with the oxygen-enriched gas, brand new gas components are provided for pre-cooling of sintered ore, quenching of the sintered ore is avoided, and the quality of the sintered ore is guaranteed. Meanwhile, low-temperature sintering flue gas is converted into high-quality flue gas, the high-quality flue gas circularly enters a sintering material layer or a waste heat recovery system, sensible heat of sintering ore and latent heat of the low-temperature sintering flue gas are fully utilized, and the waste heat utilization efficiency is improved.

Description

Technical Field

[0001] The utility model relates to a system for controlling the quality of flue gas, in particular to a system for controlling the quality of circulating flue gas and utilizing waste heat, and belongs to the field of sintering flue gas treatment. Background Art

[0002] The energy consumption of sintering process accounts for about 15% of the total energy consumption of steel enterprises, ranking second only to the ironmaking process. At present, the total amount of waste heat resources generated by large and medium-sized steel enterprises in my country for producing 1 ton of sintered ore is about 1.44GJ, and the recovery rate is only 35% to 45%. The waste heat resources are mainly composed of waste heat from sintering ore cooling and sintering flue gas, accounting for 70% and 30% of the total waste heat resources respectively. Among them, the sensible heat of sintered ore is large and of high quality, while the sensible heat and latent heat of sintering flue gas are small and of low quality.

[0003] Since 2005, some steel mills have successively recovered the sensible heat of sintered ore for power generation, expanding its utilization space and reducing the energy consumption of the sintering process. However, the current sintered ore cooling mainly adopts the traditional belt cooler or ring cooler based on the principle of high-wind fast cooling and one-time loading and unloading cooling. Regardless of the cooling method adopted, the cooler has problems such as large air leakage rate, high fan power consumption, low sensible heat recovery rate, and low boiler thermal efficiency. Therefore, some people have broken through the limitations of traditional ring cooling or vertical cooling, and proposed a sintering two-stage cooling and waste heat recovery technology for efficient recovery of sensible heat of sintered ore, that is, the sintered ore is crushed by a single roller crusher, cooled by a pre-cooling device, and then enters the existing cooling device for cooling.

[0004] During the movement of the trolley, the flue gas temperature in each sintering bellows is different. For example, the flue gas temperature in the head bellows of the sintering machine is about 120°C, the flue gas temperature in the middle bellows is about 70 to 100°C, and the flue gas temperature in the tail bellows is about 350°C. Generally, conventional sintering flue gas is discharged after desulfurization and denitrification, resulting in a large loss of flue gas waste heat and energy waste. The flue gas circulation sintering process only recycles part of the high-temperature head and tail sintering flue gas, while most of the low-temperature flue gas is discharged, which also causes waste heat. At the same time, sintering uses solid fuels such as coke powder and anthracite as heat sources. The sintering environment causes incomplete combustion, releasing CO and NO into the low-temperature flue gas. Its direct emission not only wastes the latent heat of the flue gas, but also causes environmental pollution. Therefore, how to efficiently utilize the low-temperature flue gas waste heat has become an urgent problem to be solved.

[0005] At present, in terms of sinter waste heat treatment and flue gas waste heat utilization, Patents 202110005574.8 and CN202110005673.6 disclose a sintering pre-cooling waste heat efficient utilization system, providing a pre-cooling device, hot sintered ore cooling and high-quality hot air utilization method, but do not involve the source of cooling air. Patent 201910293230.4 discloses a sintering flue gas waste heat circulation system, which realizes the recycling of high-temperature flue gas waste heat, reduces heat loss, and improves energy utilization, but there is a problem of direct emission of low-temperature flue gas. Utility Model Content

[0006] In view of the problems in the prior art that most of the low-temperature flue gas is directly discharged, resulting in waste of waste heat, and the direct emission of CO and NO in the low-temperature flue gas causes waste of flue gas latent heat and environmental pollution, the utility model proposes a method for regulating the quality of circulating flue gas, in which the flue gas from part of the head bellows and the middle bellows is oxygenated and then sent to a vertical cooling device, where it is heated and then reused, thereby making full use of the waste heat in the low-temperature sintering flue gas, increasing the flue gas circulation volume, and improving the circulating flue gas quality.

[0007] According to a first embodiment of the present utility model, a system for regulating the quality of circulating flue gas is provided.

[0008] A system for regulating the quality of circulating flue gas, the system comprising a sintering machine, a vertical cooling device, and an oxygen supply device. A first flue and a second flue are provided below the sintering machine. The head wind box and the middle wind box are connected to the bottom of the vertical cooling device through the first flue, and the oxygen supply device is connected to the bottom of the first flue or the vertical cooling device. The tail wind box is connected to the second flue.

[0009] Preferably, the head bellows are 1 / 5 to 1 / 2 of the bellows close to the head of the sintering machine, the tail bellows are 1 / 5 to 1 / 3 of the bellows at the tail of the sintering machine, and the rest are middle bellows.

[0010] Preferably, the system further comprises a third flue, part of the head wind box and part of the middle wind box are connected to the third flue, and the third flue is connected to the flue gas purification device.

[0011] Preferably, the partial head bellows is 1 / 8 to 1 / 2 of the head bellows.

[0012] Preferably, the portion of the middle bellows is 1 / 8 to 1 / 2 of the middle bellows.

[0013] Preferably, the system further comprises a flue gas circulation device. The exhaust port of the vertical cooling device is connected to the air inlet of the flue gas circulation device through a first flue gas duct. The second flue is connected to the first flue gas duct.

[0014] Preferably, the flue gas circulation device comprises a gas mixing unit, a dust removal unit, an induced draft fan and a circulating air hood which are connected in series in sequence. The air inlet of the gas mixing unit is connected to the first flue gas duct. The circulating air hood is arranged above the sintering machine.

[0015] Preferably, the flue gas circulation device further comprises a waste heat utilization unit, the air outlet of the induced draft fan is connected to the air inlet of the waste heat utilization unit, and the air outlet of the waste heat utilization unit is connected to the circulating air hood.

[0016] Preferably, a switching valve is provided below the head bellows and / or the middle bellows, so that the head bellows and / or the middle bellows can be switchably connected to the first flue or the third flue.

[0017] According to a second embodiment of the present invention, a method for controlling the quality of circulating flue gas is provided.

[0018] A method for regulating the quality of circulating flue gas, the method comprising:

[0019] 1) Mixing the head sintering flue gas in the head wind box with the middle sintering flue gas in the middle wind box to obtain mixed flue gas, supplementing oxygen into the mixed flue gas, and then introducing it from the lower end of the vertical cooling device, and the mixed flue gas is discharged after sufficient heat exchange in the vertical cooling device;

[0020] 2) The tail sintering flue gas in the tail wind box is mixed with the gas discharged from the vertical cooling device to obtain circulating gas, and the circulating gas is transported to the top of the sintering machine for reuse.

[0021] Preferably, the head sintering flue gas has a temperature of <100°C and a CO concentration of <4000 mg·m -3 The sintering flue gas in the middle has a temperature of <90°C and a CO concentration of 8000-20000 mg·m -3 , NO concentration is 200~400mg·m -3 , SO2 concentration <500mg·m -3 The flue gas of the tail sintering is of temperature>300℃ and CO concentration<1500mg·m -3 of smoke.

[0022] Preferably, after the oxygen supplementation in step 1), the oxygen content in the mixed flue gas is 20% to 28%, preferably 22% to 25%.

[0023] Preferably, the method further comprises: 3) controlling the flow of the front sintering flue gas and / or the middle sintering flue gas, and the flow of the rear sintering flue gas entering the vertical cooling device, so that the gas discharged from the vertical cooling device meets the system operation standard.

[0024] Preferably, the system operation standards include the internal temperature of the vertical cooling device, the quality of the sintered ore discharged from the vertical cooling device, and the reuse standard of the sintering machine.

[0025] Preferably, the internal temperature of the vertical cooling device is as follows: the temperature of the lower part of the vertical cooling device is 500-600°C, the temperature of the middle part is 600-850°C, and the temperature of the upper part is 700-1000°C.

[0026] Preferably, the quality of the sintered ore discharged from the vertical cooling device is as follows: the particle size composition standard of the sintered ore is a particle size range of 5-50 mm, of which the 5-10 mm particle size accounts for 20% to 27%, preferably 22% to 25%; the drum strength standard of the sintered ore is a strength index of 68% to 78%, preferably 70% to 75%.

[0027] Preferably, the sintering machine reuse standard is as follows: the temperature of the circulating gas is 130-250° C., and the oxygen content is 18%-25%, and preferably the temperature of the circulating gas is 150-200° C., and the oxygen content is 20%-23%.

[0028] Preferably, the step 3) is specifically:

[0029] 31) adjusting the number of middle wind boxes or the opening of the wind box valves connected to the first flue so that the lower temperature of the vertical cooling device is 500-600°C, the middle temperature is 600-850°C, and the upper temperature is 700-1000°C; when the temperature of the sintering flue gas in the vertical cooling device is too low, the number of the middle wind boxes is reduced or the opening of the wind box valve is reduced; when the temperature of the sintering flue gas in the vertical cooling device is too high, the number of the middle wind boxes is increased or the opening of the wind box valve is increased; the flow range q1-q6 and the temperature range t1-t6 of the exhaust gas outside the vertical cooling device are obtained;

[0030] 32) Detect the particle size composition and drum strength of the sintered ore discharged from the vertical cooling device, and adjust the number of the middle bellows connected to the first flue or the bellows valve opening to make the particle size composition and drum strength of the sintered ore meet the standards; when the 5-10mm particle size in the particle size composition of the sintered ore is greater than 27% or the drum strength is less than 68%, adjust the number of the middle bellows to decrease or the bellows valve opening to decrease; when the 5-10mm particle size in the particle size composition of the sintered ore is less than 20% or the drum strength is greater than 78%, adjust the number of the middle bellows to increase or the bellows valve opening to increase, and obtain the flow range q2 to q5 and the temperature range t2 to t5 of the exhaust gas outside the vertical cooling device;

[0031] 33) Detect the temperature and oxygen content of the mixed gas obtained by mixing the gas discharged from the vertical cooling device with the sintering flue gas in the tail bellows; when the temperature of the mixed gas is greater than 250°C, reduce the number of tail bellows or pass the mixed gas through the waste heat utilization device to control its temperature to less than 250°C; when the temperature of the mixed gas is less than 130°C, increase the number of tail bellows or reduce the number of front bellows or reduce the number of middle bellows to control its temperature to greater than 130°C; when the oxygen content of the mixed gas is greater than 25%, reduce the oxygen flow rate during the oxygen supplementation process; when the oxygen content of the mixed gas is less than 18%, increase the oxygen flow rate during the oxygen supplementation process, so that the temperature and oxygen content of the mixed gas meet the reuse standards of the sintering machine.

[0032] In the utility model, the first flue and the second flue are arranged below the sintering machine, and the flue gas in the head bellows and the middle bellows are introduced into the vertical cooling device, and oxygen is added to the vertical cooling device at the same time. Since the temperature of this part of the flue gas is relatively low and contains a high CO concentration and a low SO2 concentration, it replaces the cold air as part or all of the pre-cooling air for the high-temperature sintered ore. Compared with the cold air, the low-temperature sintering flue gas can alleviate the rapid cooling of the sintered ore and ensure the quality and yield of the sintered ore. In addition, the low-temperature sintering flue gas is introduced from the bottom of the vertical cooling device. The movement direction of the flue gas is opposite to that of the sintered ore. It passes through the sintered ore layers of different temperatures from bottom to top, and the flue gas temperature is continuously increased. The countercurrent cooling improves the gas-solid heat exchange efficiency, and the low-temperature sintering flue gas is converted into a high-quality waste heat resource. Preferably, the sintering flue gas in part of the head wind box and part of the middle wind box is selectively passed into the vertical cooling device, and by adjusting the number of the head wind box and the middle wind box, the quality of the sintered ore is ensured while increasing the circulation volume of the low-quality flue gas in the middle wind box, reducing the amount of flue gas terminal treatment, and improving the utilization rate of the waste heat of the low-temperature flue gas. The flow rate of the head sintering flue gas and the middle sintering flue gas is controlled, and the temperature and other parameters in the vertical cooling device are changed to improve the temperature of the flue gas discharged from the vertical cooling device and the quality of the sintered ore, and make the circulating flue gas meet the standards for the reuse of the sintering machine.

[0033] In the utility model, high-concentration oxygen is introduced into the low-temperature sintering flue gas. Since the low-temperature sintering flue gas contains a relatively high concentration of CO, oxygen can accelerate the oxidation process of CO. CO and oxygen are heated and burn to release heat, thereby increasing the temperature of the flue gas discharged from the vertical cooling device. At the same time, after the high-concentration oxygen is introduced, the oxygen content of the flue gas discharged from the vertical cooling device is increased. In the vertical cooling device, the temperature gradually increases from bottom to top, the lower temperature is 500-600°C, the middle temperature is 600-850°C, and the upper temperature is 700-1000°C. It can reach more than 1000°C in some parts. During the countercurrent rising process of the flue gas, gas-solid heat exchange is only carried out in the lower part. While heat exchange is carried out in the middle of the vertical cooling device, the temperature meets the conditions required for CO combustion. With the help of the excitation effect of high-concentration oxygen, CO oxidation heat release is promoted to further increase the flue gas temperature. At the same time, under the catalytic action of Fe2O3 in the sintered ore, CO-NO catalytic reaction can also occur in local areas to reduce NO in the flue gas. x content.

[0034] In the utility model, after the low-temperature sintering flue gas is heated in the vertical cooling device, it is mixed with the sintering flue gas in the wind box at the tail end of the sintering machine. After being fully mixed and dusted by the flue gas circulation device, the mixed gas is sent to the top of the sintering machine through the flue gas circulation pipeline for reuse.

[0035] In the present utility model, the low-temperature sintering flue gas in part of the head wind box and the middle wind box of the sintering machine is coupled with oxygen-rich gas as part or all of the cooling gas of the vertical cooling device. Through preliminary research, the initial flow rate range Q1 (q1~q6, q1 << q6) of the gas required for the vertical cooling device to produce qualified sinter is determined, as well as the initial temperature range T1 (the values t1~t6, t1 << t6). Then, the flue gas discharged from the vertical cooling device is detected. If the flow rate Q2 of the discharged flue gas is greater than q6 or Q2 is less than q1, the flow rate of the low-temperature sintering flue gas is regulated by increasing or decreasing the number of middle wind boxes or the valve opening degree, so that Q2' reaches the Q1 range. Similarly, the sinter discharged from the vertical cooling device is detected. If its particle size composition and drum strength do not meet the requirements, by increasing or decreasing the number of middle wind boxes or the valve opening degree, a new flue gas flow rate Q3' (the value is q2~q5, q1 < q2 < q5 < q6) and a T3' range (the values t2~t5, t1 < t2 < t5 < t6) that make the particle size composition and drum strength of the sinter meet the standards are obtained. Based on Q3' and T3', the temperature T4 of the mixed gas is further detected. If T4 > 250°C, the mixed gas is passed into the waste heat recovery system to be cooled to 150~200°C so that its temperature meets the requirements of the sintering process. In addition, the oxygen content of the mixed gas is detected. If the oxygen content is lower than 20%, more high-concentration oxygen is introduced into the low-temperature sintering flue gas to control the oxygen content of the mixed gas to reach 20~23%. Through continuous repetition of the above control process, the temperature and oxygen content of the mixed gas are continuously optimized, so as to maximize the efficiency of waste heat utilization of the sintering flue gas and the sinter, and optimize the quality of the circulating gas.

[0036] In the present utility model, regarding the value range of the high-quality sintering flue gas flow rate Q3, generally, q1 < q2 < q3 < q4 < q5 < q6 holds. If there are situations such as q4 > q5, the value range of Q3 is q3~q4 ∩ q2~q5, thereby accurately controlling the flow rate of the mixed flue gas and regulating the flow rates of the front sintering flue gas and the middle sintering flue gas.

[0037] In the present utility model, the temperature of the circulating gas is controlled at 130~250°C, and the oxygen content is controlled at 18~25%. After the circulating gas circulates above the sintering machine, it can delay the cooling rate of the upper sinter, ensure the quality of the upper sinter. At the same time, the downward-running mixed gas can increase the maximum temperature of the combustion zone and provide sufficient oxygen. The two work together to enhance the combustion efficiency of the fuel, reduce CO generation, and overall reduce the energy consumption of the sintering process.

[0038] In the present utility model, the sintering machine includes 12 - 48 wind boxes, preferably 16 - 42 wind boxes, more preferably 18 - 36 wind boxes, and further preferably 20 - 32 wind boxes. The height of the vertical cooling device is 2 - 30 m, preferably 5 - 25 m, more preferably 6 - 20 m.

[0039] Compared with the prior art, the utility model has the following beneficial effects:

[0040] 1. The utility model provides a circulating flue gas quality control system, which couples the sintering flue gas of the head bellows and the middle bellows with oxygen-rich gas, provides a new gas component for sintered ore precooling, avoids sintered ore rapid cooling, and ensures the quality of sintered ore. At the same time, the low-temperature sintering flue gas is converted into high-quality flue gas, which is circulated into the sintering material layer or the waste heat recovery system, making full use of the sensible heat of the sintered ore and the latent heat of the low-temperature sintering flue gas, and improving the waste heat utilization efficiency.

[0041] 2. The utility model provides a method for regulating the quality of circulating flue gas, which utilizes oxygen-rich gas and the high temperature environment in a vertical cooling device to promote the recovery of latent heat resources in low-temperature sintering flue gas, while controlling the oxygen content of the mixed gas to meet sintering requirements, thereby achieving flue gas circulation to increase sintering output and reduce pollutant CO emissions, and overcoming the chronic problem of reduced sintering output due to flue gas circulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic diagram of the structure of a system for regulating the quality of circulating flue gas provided by the utility model.

[0043] Figure numerals: 1: sintering machine; 101: first flue; 102: second flue; 103: head bellows; 104: middle bellows; 105: tail bellows; 106: third flue; 2: vertical cooling device; 3: oxygen supply device; 4: flue gas circulation device; 401: air mixing unit; 402: dust removal unit; 403: induced draft fan; 404: waste heat utilization unit; 405: circulating air hood. DETAILED DESCRIPTION

[0044] The technical solution of the utility model is illustrated below, and the scope of protection requested for the utility model includes but is not limited to the following embodiments.

[0045] According to a first embodiment of the present utility model, a system for regulating the quality of circulating flue gas is provided.

[0046] A system for controlling the quality of circulating flue gas, the system comprising a sintering machine 1, a vertical cooling device 2, and an oxygen supply device 3. A first flue 101 and a second flue 102 are provided below the sintering machine 1. A head wind box 103 and a middle wind box 104 are connected to the bottom of the vertical cooling device 2 through the first flue 101, and the oxygen supply device 3 is connected to the bottom of the first flue 101 or the vertical cooling device 2. A tail wind box 105 is connected to the second flue 102.

[0047] Preferably, the head bellows 103 are 1 / 5 to 1 / 2 of the bellows close to the head of the sintering machine, the tail bellows are 1 / 5 to 1 / 3 of the bellows at the tail of the sintering machine, and the rest are middle bellows.

[0048] Preferably, the system further comprises a third flue 106. Part of the head wind box 103 and part of the middle wind box 104 are connected to the third flue 106. The third flue 106 is connected to a flue gas purification device.

[0049] Preferably, part of the head bellows 103 is 1 / 8 to 1 / 2 of the head bellows.

[0050] Preferably, part of the middle bellows 104 is 1 / 8 to 1 / 2 of the middle bellows.

[0051] Preferably, the system further comprises a flue gas circulation device 4. The exhaust port of the vertical cooling device 2 is connected to the air inlet of the flue gas circulation device 4 through the first flue gas duct L1. The second flue 102 is connected to the first flue gas duct L1.

[0052] Preferably, the flue gas circulation device 4 comprises a gas mixing unit 401, a dust removal unit 402, an induced draft fan 403 and a circulating air hood 405 which are connected in series. The air inlet of the gas mixing unit 401 is connected to the first flue gas duct L1. The circulating air hood 405 is arranged above the sintering machine 1.

[0053] Preferably, the flue gas circulation device 4 further includes a waste heat utilization unit 404 , the air outlet of the induced draft fan 403 is connected to the air inlet of the waste heat utilization unit 404 , and the air outlet of the waste heat utilization unit 404 is connected to the circulating air hood 405 .

[0054] Preferably, a switching valve is provided below the head wind box 103 and / or the middle wind box 104 , so that the head wind box 103 and / or the middle wind box 104 can be switchably connected to the first flue 101 or the third flue 106 .

[0055] According to a second embodiment of the present invention, a method for controlling the quality of circulating flue gas is provided.

[0056] A method for regulating the quality of circulating flue gas, the method comprising:

[0057] 1) Mixing the head sintering flue gas in the head wind box with the middle sintering flue gas in the middle wind box to obtain mixed flue gas, supplementing oxygen into the mixed flue gas, and then introducing it from the lower end of the vertical cooling device, and the mixed flue gas is discharged after sufficient heat exchange in the vertical cooling device;

[0058] 2) The tail sintering flue gas in the tail wind box is mixed with the gas discharged from the vertical cooling device to obtain circulating gas, and the circulating gas is transported to the top of the sintering machine for reuse.

[0059] Preferably, the head sintering flue gas has a temperature of <100°C and a CO concentration of <4000 mg·m -3 The sintering flue gas in the middle has a temperature of <90°C and a CO concentration of 8000-20000 mg·m -3 , NO concentration is 200~400mg·m -3 , SO2 concentration <500mg·m -3 The flue gas of the tail sintering is of temperature>300℃ and CO concentration<1500mg·m -3 and / or

[0060] After the oxygen supplementation in step 1), the oxygen content in the mixed flue gas is 20% to 28%, preferably 22% to 25%.

[0061] Preferably, the method further comprises: 3) controlling the flow of the front sintering flue gas and / or the middle sintering flue gas, and the flow of the rear sintering flue gas entering the vertical cooling device, so that the gas discharged from the vertical cooling device meets the system operation standard.

[0062] Preferably, the system operation standards include the internal temperature of the vertical cooling device, the quality of the sintered ore discharged from the vertical cooling device, and the reuse standard of the sintering machine.

[0063] Preferably, the internal temperature of the vertical cooling device is as follows: the temperature of the lower part of the vertical cooling device is 500-600°C, the temperature of the middle part is 600-850°C, and the temperature of the upper part is 700-1000°C.

[0064] Preferably, the quality of the sintered ore discharged from the vertical cooling device is as follows: the particle size composition standard of the sintered ore is a particle size range of 5-50 mm, of which the 5-10 mm particle size accounts for 20% to 27%, preferably 22% to 25%; the drum strength standard of the sintered ore is a strength index of 68% to 78%, preferably 70% to 75%.

[0065] Preferably, the sintering machine reuse standard is as follows: the temperature of the circulating gas is 130-250° C., and the oxygen content is 18%-25%, and preferably the temperature of the circulating gas is 150-200° C., and the oxygen content is 20%-23%.

[0066] Preferably, the step 3) is specifically:

[0067] 31) adjusting the number of middle wind boxes or the opening of the wind box valves connected to the first flue so that the lower temperature of the vertical cooling device is 500-600°C, the middle temperature is 600-850°C, and the upper temperature is 700-1000°C; when the temperature of the sintering flue gas in the vertical cooling device is too low, the number of the middle wind boxes is reduced or the opening of the wind box valve is reduced; when the temperature of the sintering flue gas in the vertical cooling device is too high, the number of the middle wind boxes is increased or the opening of the wind box valve is increased; the flow range q1-q6 and the temperature range t1-t6 of the exhaust gas outside the vertical cooling device are obtained;

[0068] 32) Detect the particle size composition and drum strength of the sintered ore discharged from the vertical cooling device, and adjust the number of the middle bellows connected to the first flue or the bellows valve opening to make the particle size composition and drum strength of the sintered ore meet the standards; when the 5-10mm particle size in the particle size composition of the sintered ore is greater than 27% or the drum strength is less than 68%, adjust the number of the middle bellows to decrease or the bellows valve opening to decrease; when the 5-10mm particle size in the particle size composition of the sintered ore is less than 20% or the drum strength is greater than 78%, adjust the number of the middle bellows to increase or the bellows valve opening to increase, and obtain the flow range q2 to q5 and the temperature range t2 to t5 of the exhaust gas outside the vertical cooling device;

[0069] 33) Detect the temperature and oxygen content of the mixed gas obtained by mixing the gas discharged from the vertical cooling device with the sintering flue gas in the tail bellows; when the temperature of the mixed gas is greater than 250°C, reduce the number of tail bellows or pass the mixed gas through the waste heat utilization device to control its temperature to less than 250°C; when the temperature of the mixed gas is less than 130°C, increase the number of tail bellows or reduce the number of front bellows or reduce the number of middle bellows to control its temperature to greater than 130°C; when the oxygen content of the mixed gas is greater than 25%, reduce the oxygen flow rate during the oxygen supplementation process; when the oxygen content of the mixed gas is less than 18%, increase the oxygen flow rate during the oxygen supplementation process, so that the temperature and oxygen content of the mixed gas meet the reuse standards of the sintering machine.

[0070] Example 1

[0071] A system for controlling the quality of circulating flue gas, the system comprising a sintering machine 1, a vertical cooling device 2, and an oxygen supply device 3. A first flue 101 and a second flue 102 are provided below the sintering machine 1. A head wind box 103 and a middle wind box 104 are connected to the bottom of the vertical cooling device 2 through the first flue 101, and the oxygen supply device 3 is connected to the first flue 101. A tail wind box 105 is connected to the second flue 102.

[0072] Example 2

[0073] Example 1 is repeated, except that the head bellows 103 is the bellows of 1 / 2 close to the head of the sintering machine, the tail bellows is the bellows of 1 / 3 at the tail of the sintering machine, and the rest are middle bellows.

[0074] Example 3

[0075] Example 2 is repeated, except that the system further includes a third flue 106. One-third of the head wind boxes 103 and one-third of the middle wind boxes 104 are connected to the third flue 106. The third flue 106 is connected to the flue gas purification device.

[0076] Example 4

[0077] Example 3 is repeated, except that the system further includes a flue gas circulation device 4. The exhaust port of the vertical cooling device 2 is connected to the air inlet of the flue gas circulation device 4 through the first flue gas duct L1. The second flue 102 is connected to the first flue gas duct L1.

[0078] Example 5

[0079] Example 4 is repeated, except that the flue gas circulation device 4 includes a gas mixing unit 401, a dust removal unit 402, an induced draft fan 403 and a circulating air hood 405 connected in series. The air inlet of the gas mixing unit 401 is connected to the first flue gas duct L1. The circulating air hood 405 is arranged above the sintering machine 1.

[0080] Example 6

[0081] Example 5 is repeated, except that the flue gas circulation device 4 further includes a waste heat utilization unit 404 , the air outlet of the induced draft fan 403 is connected to the air inlet of the waste heat utilization unit 404 , and the air outlet of the waste heat utilization unit 404 is connected to the circulating air hood 405 .

[0082] Example 7

[0083] Example 6 is repeated, except that a switching valve is provided below the head wind box 103 and the middle wind box 104 , so that the head wind box 103 and the middle wind box 104 can be switchably connected to the first flue 101 or the third flue 106 .

[0084] Example 8

[0085] The system described in Example 7 is used to treat the sintering flue gas:

[0086] There are 24 bellows under the sintering machine, of which bellows No. 1 to 3 are head bellows, bellows No. 4 to 19 are middle bellows, and bellows No. 20 to 24 are tail bellows.

[0087] 1) Mix the head sintering flue gas in the No. 1 to 3 wind boxes with the middle sintering flue gas in the No. 9 to 14 wind boxes to obtain mixed flue gas, add oxygen to the mixed flue gas to an oxygen content of 27%, and introduce it from the lower end of the vertical cooling device. The mixed flue gas is discharged after sufficient heat exchange in the vertical cooling device;

[0088] 2) The tail sintering flue gas in the tail wind box is mixed with the gas discharged from the vertical cooling device to obtain circulating gas, and the circulating gas is transported to the top of the sintering machine for reuse.

[0089] 31) Detect the temperature of the sintering flue gas in the vertical cooling device. The lower temperature of the vertical cooling device is 491°C, the middle temperature is 588°C, and the upper temperature is 665°C. Reduce the number of middle wind boxes and pass the middle sintering flue gas in the No. 9 wind box into the third flue. After the adjustment, the lower temperature of the vertical cooling device is 526°C, the middle temperature is 632°C, and the upper temperature is 755°C. The flow range of the exhaust gas outside the vertical cooling device is 384300~415080m 3 / h, temperature range 175~149℃.

[0090] 32) The particle size composition and drum strength of the sintered ore discharged from the vertical cooling device were detected. The 5-10 mm particle size accounted for 25% of the sintered ore particle size composition, and the drum strength was 70%. The flow rate range of the exhaust gas from the vertical cooling device was 368900~399700m 3 / h, and temperature range 167~154℃.

[0091] 33) The temperature of the mixed gas obtained by mixing the gas discharged from the vertical cooling device and the sintering flue gas in the tail wind box is detected to be 195°C and the oxygen content is 26%. The oxygen flow rate during the oxygen supplementation process is reduced so that the oxygen content of the mixed gas is 23%. The regulation is completed.

Claims

1. A system for regulating the quality of circulating flue gas, characterized in that: The system comprises a sintering machine (1), a vertical cooling device (2), and an oxygen supply device (3); a first flue (101) and a second flue (102) are provided below the sintering machine (1); a head wind box (103) and a middle wind box (104) are connected to the bottom of the vertical cooling device (2) through the first flue (101), and the oxygen supply device (3) is connected to the first flue (101) or the bottom of the vertical cooling device (2); and a tail wind box (105) is connected to the second flue (102).

2. The system for controlling the quality of circulating flue gas according to claim 1, characterized in that: The head bellows (103) are 1 / 5 to 1 / 2 of the bellows close to the head of the sintering machine, the tail bellows are 1 / 5 to 1 / 3 of the bellows at the tail of the sintering machine, and the rest are middle bellows.

3. The system for controlling the quality of circulating flue gas according to claim 2, characterized in that: The system further comprises a third flue (106); part of the head wind box (103) and part of the middle wind box (104) are connected to the third flue (106); and the third flue (106) is connected to a flue gas purification device.

4. The system for controlling the quality of circulating flue gas according to claim 3, characterized in that: The portion of the head bellows (103) is 1 / 8 to 1 / 2 of the head bellows; and / or Part of the middle bellows (104) is 1 / 8 to 1 / 2 of the middle bellows.

5. The system for controlling the quality of circulating flue gas according to any one of claims 1 to 3, characterized in that: The system also includes a flue gas circulation device (4); the exhaust port of the vertical cooling device (2) is connected to the air inlet of the flue gas circulation device (4) through a first flue gas duct (L1); and the second flue (102) is connected to the first flue gas duct (L1).

6. The system for controlling the quality of circulating flue gas according to claim 5, characterized in that: The flue gas circulation device (4) comprises a gas mixing unit (401), a dust removal unit (402), an induced draft fan (403) and a circulating air hood (405) which are connected in series in sequence; the air inlet of the gas mixing unit (401) is connected to a first flue gas duct (L1); and the circulating air hood (405) is arranged above the sintering machine (1).

7. The system for controlling the quality of circulating flue gas according to claim 6, characterized in that: The flue gas circulation device (4) further comprises a waste heat utilization unit (404), the air outlet of the induced draft fan (403) is connected to the air inlet of the waste heat utilization unit (404), and the air outlet of the waste heat utilization unit (404) is connected to the circulating air hood (405).

8. The system for controlling the quality of circulating flue gas according to claim 3, characterized in that: A switching valve is provided below the head wind box (103) and / or the middle wind box (104), and the head wind box (103) and / or the middle wind box (104) can be switchably connected to the first flue (101) or the third flue (106).

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