Low-quality sintering flue gas waste heat upgrading system

Abstract

The utility model provides a low-quality sintering flue gas waste heat upgrading system. The system comprises a sintering machine, a vertical pre-cooling device and an annular cooler. The tail of the sintering machine is provided with a machine tail cover, and the bottom of the machine tail cover is communicated with the top of the vertical pre-cooling device. And a crushing and discharging device is arranged in the machine tail cover. And the circular cooler is arranged below the vertical pre-cooling device. An air bellow is arranged below the sintering machine, and the air bellow is divided into a front air bellow and a rear air bellow according to the running direction of the sintering machine. And the front air box is communicated with the bottom of the vertical pre-cooling device through a first flue. And the rear air bellow is communicated with the tail cover through a second flue. According to the system, the temperature of sintering flue gas is increased through heat exchange with the sintering ore, the waste heat recovery efficiency is improved, efficient waste heat recovery, quality improvement and efficiency improvement of the sintering flue gas are achieved, and meanwhile the situation that the performance of the sintering ore is reduced due to quenching of the sintering ore is prevented through gradient cooling.

Description

Technical Field

[0001] The utility model relates to a system for improving the quality of flue gas waste heat, in particular to a system for improving the quality of low-quality sintering flue gas waste heat, and belongs to the field of sintering waste heat utilization. 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, but 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 in quantity and high in quality, while the sensible heat and latent heat of sintering flue gas are small in quantity and low in quality.

[0003] Since 2005, some steel plants 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 high air leakage rate, high fan power consumption, low sensible heat recovery rate, and low boiler thermal efficiency.

[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. At the same time, a large amount of energy consumption is required in the flue gas treatment process. Therefore, how to efficiently utilize the low-temperature flue gas waste heat has become an urgent problem to be solved.

[0005] In addition, during the cooling process of sintered ore, outside air is often directly introduced into the ring cooler. However, the air temperature is relatively low, which can easily cause rapid cooling of the sintered ore, resulting in reduced sintered ore quality and yield.

[0006] In terms of sinter waste heat treatment and flue gas waste heat utilization, patents CN202110005574.8 and CN202110005673.6 disclose a sintering pre-cooling waste heat efficient utilization system, providing a pre-cooling device, hot sinter 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. Patent 201810355829.1 discloses a synergistic treatment process for sinter waste heat and sintering flue gas pollutants. By heat exchange treatment and CO removal between sintering flue gas and sintered ore, the removal and utilization of CO are solved, and the synergistic treatment of sinter waste heat and sintering flue gas pollutants is realized, but there are problems of secondary auxiliary fuel consumption, complicated process flow and incomplete cooling of sintered ore. Utility Model Content

[0007] The problem of incomplete utilization of flue gas generated by sintering is currently addressed, especially the direct discharge of sintering flue gas from most bellows of the sintering machine, and the large amount of CO and NO in the flue gas, which not only wastes a large amount of sensible heat and latent heat, but also causes environmental pollution. At the same time, in terms of sintering waste heat treatment and flue gas waste heat utilization, the existing technology often has problems such as complicated processes and incomplete cooling of sintered ore. The utility model proposes a method and system for improving the quality of low-quality sintering flue gas waste heat, which passes the low-temperature flue gas in the bellows below the sintering machine into the bottom of the vertical pre-cooling device, and the high-temperature flue gas into the top of the vertical pre-cooling device, so as to achieve the best pre-cooling effect while increasing the flue gas temperature, and at the same time utilize the latent heat in the flue gas to make it a high-quality sintering flue gas that is easy to utilize waste heat.

[0008] According to a first embodiment of the utility model, a method for upgrading low-quality sintering flue gas by utilizing waste heat is provided.

[0009] A method for improving the quality of low-quality sintering flue gas by waste heat, the method comprising: 1) after the sintering material is sintered on a sintering machine, it is discharged through a crushing and unloading device at the tail of the sintering machine, and then enters a vertical precooling device for precooling, and finally enters a ring cooler for recooling, and after cooling, a finished sintered ore is obtained;

[0010] 2) The rear sintering flue gas in the rear bellows of the sintering machine is introduced into the crushing and unloading device, and heat exchanged with the crushed sintered ore in the crushing and unloading device; the front sintering flue gas in the front bellows of the sintering machine is sent to the vertical precooling device to exchange heat with the sintered ore; the front sintering flue gas after heat exchange is merged with the rear sintering flue gas and discharged from the vertical precooling device to obtain high-quality sintering flue gas.

[0011] Preferably, the front sintering flue gas has a temperature of <150°C and a CO concentration of ≥2000 mg·m -3 , NO concentration <400 mg·m -3 The post-sintering flue gas has a temperature of ≥250°C and a CO concentration of <2000mg·m -3 .

[0012] Preferably, the middle sintering flue gas in the middle wind box of the sintering machine is purified and then discharged; preferably, the temperature of the middle sintering flue gas is 130-300°C, and the SO2 concentration is >500mg·m -3 ; The temperature of the front sintering flue gas is less than 130℃, and the CO concentration is 3000~20000mg·m -3 , NO concentration 70~400mg·m -3 ; The temperature of the flue gas from the rear sintering is >300℃, and the CO concentration is <1500mg·m -3 .

[0013] Preferably, the method further comprises: 3) the high-quality sintering flue gas is sent to a waste heat utilization process after dust removal, and discharged after waste heat utilization is completed.

[0014] Preferably, the method further comprises: 4) adjusting the flow of the front sintering flue gas or the rear sintering flue gas so that the vertical precooling device is in a stable operating state, and recording the high-quality sintering flue gas flow Q3 and temperature T3 when the vertical precooling device is in a stable state.

[0015] Preferably, the method further comprises: 5) detecting the performance of the sintered ore discharged from the bottom of the vertical precooling device, and controlling the flow rate of the front sintering flue gas or the flow rate of the rear sintering flue gas to ensure that the performance of the sintered ore discharged from the bottom of the vertical precooling device meets the standards.

[0016] Preferably, the method further comprises: 6) detecting the temperature of the high-quality sintering flue gas, and adjusting the flow rate of the sintering flue gas sent to the vertical precooling device through the first flue or the second flue, so that the temperature of the high-quality sintering flue gas is within an optimal range.

[0017] Preferably, the vertical precooling device described in step 4) is in a stable operating state: the temperature inside the vertical precooling device gradually increases from bottom to top, wherein the temperature of the lower part of the vertical precooling 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.

[0018] Preferably, the step 4) is specifically as follows: the flow rate of the sintering flue gas in the front is detected to be Q1, and the temperature is T1, and the flow rate of the sintering flue gas in the rear is Q2, and the temperature is T2; when the temperature in the vertical precooling device is too high, the flow rate of the sintering flue gas in the front is increased or the flow rate of the sintering flue gas in the rear is reduced; when the temperature in the vertical precooling device is too low, the flow rate of the sintering flue gas in the front is reduced or the flow rate of the sintering flue gas in the rear is increased; when the vertical precooling device is in a stable operating state, the high-quality sintering flue gas discharged from the vertical precooling device is detected, and the flow rate is measured to be Q3 and the temperature is T3; further, the value range of the high-quality sintering flue gas flow rate Q3 is q1~q6, and the value range of the high-quality sintering flue gas temperature T3 is t1~t6.

[0019] Preferably, the sintered ore properties in step 5) are the particle size composition and drum strength of the sintered ore; preferably, the particle size composition has a particle size requirement of 5-50 mm, of which the 5-10 mm particle size accounts for 20% to 27%, preferably 22% to 25%.

[0020] Preferably, the drum strength is in the range of 68% to 78%, preferably 70% to 75%.

[0021] Preferably, the step 5) is specifically as follows: detecting the particle size composition and drum strength of the sintered ore discharged from the bottom of the vertical precooling device, and when the 5-10 mm particle size in the particle size composition of the sintered ore is >27% or the drum strength is <68%, reducing the number of front bellows or increasing the number of rear bellows; when the 5-10 mm particle size in the particle size composition of the sintered ore is <20% or the drum strength is >78%, increasing the number of front bellows or reducing the number of rear bellows; further, when the particle size composition and drum strength of the sintered ore discharged from the bottom of the vertical precooling device meet the standards, the value range of the high-quality sintering flue gas flow rate Q3 is q2-q5, and the value range of the high-quality sintering flue gas temperature T3 is t2-t5.

[0022] Preferably, the optimal range of the temperature of the high-quality sintering flue gas is t3-t4, wherein t3≥t2, t4≤t5; the specific value is determined according to the flue gas temperature required for waste heat utilization.

[0023] Preferably, the step 6) is specifically as follows: detecting the temperature of the high-quality sintering flue gas, and when the temperature of the high-quality sintering flue gas is too high, increasing the number of front bellows or reducing the number of rear bellows; when the temperature of the high-quality sintering flue gas is too low, reducing the number of front bellows or increasing the number of rear bellows; further obtaining that, when the temperature of the high-quality sintering flue gas is between t3 and t4, the flow rate Q3 of the high-quality sintering flue gas has a value range of q3 to q4, wherein q3 ≥ q2, q4 ≤ q5.

[0024] According to a second embodiment of the present utility model, a system for upgrading the quality of low-quality sintering flue gas by using waste heat is provided.

[0025] A system for improving the quality of low-quality sintering flue gas by waste heat, the system comprising a sintering machine, a vertical precooling device, and a ring cooler. A tail hood is provided at the rear of the sintering machine, and the bottom of the tail hood is connected to the top of the vertical precooling device. A crushing and unloading device is provided in the tail hood. The ring cooler is arranged below the vertical precooling device. A bellows is provided below the sintering machine, and the bellows are divided into a front bellows and a rear bellows according to the running direction of the sintering machine. The front bellows is connected to the bottom of the vertical precooling device through a first flue. The rear bellows is connected to the tail hood through a second flue.

[0026] Preferably, the system further comprises a middle wind box and a third flue. The front wind box is the wind box of 1 / 3 to 2 / 3 of the head of the sintering machine, the tail wind box is the wind box of 1 / 6 to 1 / 3 of the tail of the sintering machine, and the rest are middle wind boxes.

[0027] Preferably, the middle wind box is switchably connected to the first flue and the third flue; the third flue is connected to the flue gas purification device.

[0028] Preferably, the system further comprises a waste heat utilization device. An air outlet is provided in the middle of the vertical precooling device, and the air outlet is connected to the air inlet of the waste heat utilization device through a first flue gas delivery pipe. The air outlet of the waste heat utilization device is connected to the third flue through a second flue gas delivery pipe.

[0029] Preferably, a dust removal device is also provided on the first flue gas conveying duct.

[0030] In the utility model, the bellows below the sintering machine are divided into a front bellows and a rear bellows, and the sintering flue gas in the front bellows is sintered and transported to the vertical precooling device. The temperature of the front sintering flue gas is relatively low. After being introduced into the vertical precooling device, it exchanges heat with the sintered ore to increase the temperature of the front sintering flue gas. Since the movement directions of the sintered ore and the sintering flue gas are opposite, countercurrent cooling improves the gas-solid heat exchange efficiency and wind temperature. When the front sintering flue gas runs to the middle of the vertical precooling device, the flue gas temperature can reach 400-450°C, which is converted into high-quality waste heat resources. In addition, the rear sintering flue gas of the rear bellows is introduced into the crushing and unloading device to exchange heat with the crushed sintered ore. The temperature of the tail sintering flue gas is relatively high, which can reach 350°C. After heat exchange with the newly crushed high-temperature sintered ore, the temperature of the sintering flue gas can be further increased. After the heat exchange is completed, it merges with the front sintering flue gas and is discharged from the vertical precooling device to obtain high-quality sintering flue gas. In addition, compared with using cold air to directly cool the sintered ore, the front sintering flue gas can alleviate the rapid cooling of the sintered ore and ensure the quality and yield of the sintered ore. At the same time, the sintered ore is first pre-cooled by the high-temperature rear sintering flue gas, and then pre-cooled by the slightly lower temperature front sintering flue gas. The gradient cooling allows the sintered ore to fully adapt to the temperature of the cooling gas to prevent rapid cooling.

[0031] In the utility model, the bellows below the sintering machine is further divided into a front bellows, a middle bellows and a rear bellows, and the middle sintering flue gas in the middle bellows is introduced into the third flue, thereby increasing the temperature of the front sintering flue gas, further preventing the sintered ore from being rapidly cooled in the vertical precooling device, and increasing the temperature of the high-quality sintering flue gas discharged from the vertical precooling device.

[0032] In the utility model, since the front sintering flue gas contains CO and NO, after entering the vertical precooling device, as the front sintering flue gas moves to the middle and upper part of the vertical precooling device, the flue gas temperature gradually rises, meeting the conditions required for CO combustion, promoting the oxidation and heat release of low-concentration CO in the flue gas, and further increasing the flue gas temperature. In addition, under the catalytic action of Fe2O3, a CO-NO catalytic reduction reaction can also occur locally, reducing NO in the sintering flue gas. x While making full use of the latent heat in the sintering flue gas, the nitrogen oxides in the flue gas are removed, reducing the burden of subsequent flue gas purification. At the same time, the temperature of the flue gas is increased by oxidation heat release to prevent the rapid cooling of the sintered ore.

[0033] In the utility model, after high-quality sintering flue gas is discharged, particulate matter in the flue gas is removed by a dust removal device, and then sent to a waste heat utilization process to recover the waste heat of the high-temperature flue gas, thereby improving the waste heat recovery rate and solving the problem that the sintering flue gas temperature is low and waste heat cannot be recovered.

[0034] In the present invention, in order to ensure the stable operation of the vertical precooling device, realize the normal reaction of CO and NO in the vertical precooling device, increase the temperature of the sintering flue gas, detect the temperature of each area in the vertical precooling device, and change the flow rate and temperature of the sintering flue gas in the vertical precooling device by controlling the flow rate of the front sintering flue gas and the rear sintering flue gas, so as to make the temperature in the vertical precooling device within the set range. Preferably, in order to ensure the cooling effect of the sintered ore, the present invention realizes efficient and high-quality cooling of the sintered ore by detecting the particle size composition and drum strength of the sintered ore discharged from the vertical precooling device, and controlling the flow rate and temperature of the sintering flue gas in the vertical precooling device, wherein the flue gas flow rate and temperature in the vertical precooling device are changed by controlling the flow rate of the front sintering flue gas and the rear sintering flue gas. Further preferably, in order to meet the demand for the temperature of the sintering flue gas for subsequent waste heat utilization, the temperature of the high-quality sintering flue gas is detected, and the flow rate of the front sintering flue gas and the rear sintering flue gas is controlled to make the temperature of the high-quality sintering flue gas within the optimal range.

[0035] In the utility model, in the process of changing the sintering flue gas in the vertical precooling device by controlling the flow rate of the front sintering flue gas and the rear sintering flue gas, the first control sequence is to increase or decrease the number of the front bellows or the bellows valve opening, and the second control sequence is to increase or decrease the number of the rear bellows or the bellows valve opening.

[0036] In the present utility model, by using the front sintering flue gas and the rear sintering flue gas, while cooling the sintered ore, the temperature of the sintering flue gas is increased to obtain high-quality sintering flue gas that can be used for waste heat utilization, fully utilizing the sensible heat in the sintering flue gas, increasing the waste heat recovery efficiency, and realizing the efficient recovery and quality improvement and efficiency increase of the sintering flue gas waste heat. At the same time, CO and NO in the sintering flue gas are purified, realizing the latent heat recovery utilization and the ultimate energy efficiency, generally reducing the pollutant emissions, reducing the cost of subsequent flue gas treatment, and also having the effect of preventing the rapid cooling of the sintered ore and improving the performance of the cooled sintered ore.

[0037] 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. When 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 high-quality sintering flue gas and regulating the flow rates of the front sintering flue gas and the rear sintering flue gas.

[0038] In the present utility model, while retaining the annular cooler, a vertical pre-cooling device is newly added to pre-cool the sintered ore, with high heat exchange efficiency, which can reduce the cooling air volume in the annular cooler and appropriately reduce the area of the annular cooler.

[0039] 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, and more preferably 6 - 20 m.

[0040] Compared with the selected prior art, the present utility model has the following beneficial effects:

[0041] 1. A method and system for improving the quality of low-quality sintering flue gas waste heat provided by the present utility model introduce the front sintering flue gas and the rear sintering flue gas of the sintering machine into the vertical pre-cooling device, increase the temperature of the sintering flue gas by heat exchange with the sintered ore, increase the waste heat recovery efficiency, realize the efficient recovery and quality improvement and efficiency increase of the sintering flue gas waste heat, and at the same time prevent the rapid cooling of the sintered ore through gradient cooling, resulting in a decline in the performance of the sintered ore.

[0042] 2. A method and system for improving the quality of low-quality sintering flue gas waste heat provided by the present utility model, while exchanging heat in the vertical pre-cooling device, burn the high-concentration CO in the flue gas to release heat, which is beneficial to realizing the potential energy recovery utilization and the ultimate energy efficiency. At the same time, a NO-CO catalytic reduction reaction occurs in a local area in the vertical pre-cooling device to reduce the NO x content in the high-quality sintering flue gas, reduce pollutant emissions, and reduce the flue gas treatment cost.

[0043] 3. The utility model provides a method and system for improving the quality of low-quality sintering flue gas by waste heat. By controlling the number of front bellows and rear bellows, the flow rates of low-temperature flue gas and high-temperature flue gas are changed, thereby continuously optimizing the working state of the system and improving the quality of sintered ore and sintering flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A schematic structural diagram of a system for improving the quality of low-quality sintering flue gas waste heat provided by the utility model.

[0045] Figure numerals: 1: sintering machine; 101: tail cover; 102: crushing and unloading device; 103: front bellows; 104: rear bellows; 105: middle bellows; 2: vertical pre-cooling device; 3: ring cooler; 4: waste heat utilization device; 5: dust removal device; L1: first flue; L2: second flue; L3: third flue; G1: first flue gas conveying duct. DETAILED DESCRIPTION

[0046] 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.

[0047] According to a first embodiment of the utility model, a method for upgrading low-quality sintering flue gas by utilizing waste heat is provided.

[0048] A method for improving the quality of low-quality sintering flue gas by waste heat, the method comprising: 1) after the sintering material is sintered on a sintering machine, it is discharged through a crushing and unloading device at the tail of the sintering machine, and then enters a vertical precooling device for precooling, and finally enters a ring cooler for recooling, and after cooling, a finished sintered ore is obtained;

[0049] 2) The rear sintering flue gas in the rear bellows of the sintering machine is introduced into the crushing and unloading device, and heat exchanged with the crushed sintered ore in the crushing and unloading device; the front sintering flue gas in the front bellows of the sintering machine is sent to the vertical precooling device to exchange heat with the sintered ore; the front sintering flue gas after heat exchange is merged with the rear sintering flue gas and discharged from the vertical precooling device to obtain high-quality sintering flue gas.

[0050] Preferably, the front sintering flue gas has a temperature of <150°C and a CO concentration of ≥2000 mg·m -3 , NO concentration <400 mg·m -3 The post-sintering flue gas has a temperature of ≥250°C and a CO concentration of <2000mg·m -3 ;

[0051] Preferably, the middle sintering flue gas in the middle wind box of the sintering machine is purified and then discharged; preferably, the temperature of the middle sintering flue gas is 130-300°C, and the SO2 concentration is >500mg·m -3; The temperature of the front sintering flue gas is less than 130℃, and the CO concentration is 3000~20000mg·m -3 , NO concentration 70~400mg·m -3 ; The temperature of the flue gas from the rear sintering is >300℃, and the CO concentration is <1500mg·m -3 .

[0052] Preferably, the method further comprises: 3) the high-quality sintering flue gas is sent to a waste heat utilization process after dust removal, and discharged after waste heat utilization is completed.

[0053] Preferably, the method further comprises: 4) adjusting the flow of the front sintering flue gas or the rear sintering flue gas so that the vertical precooling device is in a stable operating state, and recording the high-quality sintering flue gas flow Q3 and temperature T3 when the vertical precooling device is in a stable state.

[0054] Preferably, the method further comprises: 5) detecting the performance of the sintered ore discharged from the bottom of the vertical precooling device, and controlling the flow rate of the front sintering flue gas or the flow rate of the rear sintering flue gas to ensure that the performance of the sintered ore discharged from the bottom of the vertical precooling device meets the standards.

[0055] Preferably, the method further comprises: 6) detecting the temperature of the high-quality sintering flue gas, and adjusting the flow rate of the sintering flue gas sent to the vertical precooling device through the first flue or the second flue, so that the temperature of the high-quality sintering flue gas is within an optimal range.

[0056] Preferably, the vertical precooling device described in step 4) is in a stable operating state: the temperature inside the vertical precooling device gradually increases from bottom to top, wherein the temperature of the lower part of the vertical precooling 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.

[0057] Preferably, the step 4) is specifically as follows: the flow rate of the sintering flue gas in the front is detected to be Q1, and the temperature is T1, and the flow rate of the sintering flue gas in the rear is Q2, and the temperature is T2; when the temperature in the vertical precooling device is too high, the flow rate of the sintering flue gas in the front is increased or the flow rate of the sintering flue gas in the rear is reduced; when the temperature in the vertical precooling device is too low, the flow rate of the sintering flue gas in the front is reduced or the flow rate of the sintering flue gas in the rear is increased; when the vertical precooling device is in a stable operating state, the high-quality sintering flue gas discharged from the vertical precooling device is detected, and the flow rate is measured to be Q3 and the temperature is T3; further, the value range of the high-quality sintering flue gas flow rate Q3 is q1~q6, and the value range of the high-quality sintering flue gas temperature T3 is t1~t6.

[0058] Preferably, the sintered ore properties in step 5) are the particle size composition and drum strength of the sintered ore; preferably, the particle size composition has a particle size requirement of 5-50 mm, of which the 5-10 mm particle size accounts for 20% to 27%, preferably 22% to 25%.

[0059] Preferably, the drum strength is in the range of 68% to 78%, preferably 70% to 75%.

[0060] Preferably, the step 5) is specifically as follows: detecting the particle size composition and drum strength of the sintered ore discharged from the bottom of the vertical precooling device, and when the 5-10 mm particle size in the particle size composition of the sintered ore is >27% or the drum strength is <68%, reducing the number of front bellows or increasing the number of rear bellows; when the 5-10 mm particle size in the particle size composition of the sintered ore is <20% or the drum strength is >78%, increasing the number of front bellows or reducing the number of rear bellows; further, when the particle size composition and drum strength of the sintered ore discharged from the bottom of the vertical precooling device meet the standards, the value range of the high-quality sintering flue gas flow rate Q3 is q2-q5, and the value range of the high-quality sintering flue gas temperature T3 is t2-t5.

[0061] Preferably, the optimal range of the temperature of the high-quality sintering flue gas is t3-t4, wherein t3≥t2, t4≤t5; the specific value is determined according to the flue gas temperature required for waste heat utilization.

[0062] Preferably, the step 6) is specifically as follows: detecting the temperature of the high-quality sintering flue gas, and when the temperature of the high-quality sintering flue gas is too high, increasing the number of front bellows or reducing the number of rear bellows; when the temperature of the high-quality sintering flue gas is too low, reducing the number of front bellows or increasing the number of rear bellows; further obtaining that, when the temperature of the high-quality sintering flue gas is between t3 and t4, the flow rate Q3 of the high-quality sintering flue gas has a value range of q3 to q4, wherein q3 ≥ q2, q4 ≤ q5.

[0063] According to a second embodiment of the present utility model, a system for upgrading the quality of low-quality sintering flue gas by using waste heat is provided.

[0064] A system for improving the quality of low-quality sintering flue gas by waste heat, the system comprising a sintering machine 1, a vertical precooling device 2, and a ring cooler 3. A tail hood 101 is provided at the rear of the sintering machine 1, and the bottom of the tail hood 101 is connected to the top of the vertical precooling device 2. A crushing and unloading device 102 is provided in the tail hood 101. The ring cooler 3 is arranged below the vertical precooling device 2. A bellows is provided below the sintering machine 1, and the bellows are divided into a front bellows 103 and a rear bellows 104 according to the running direction of the sintering machine. The front bellows 103 is connected to the bottom of the vertical precooling device 2 through a first flue L1. The rear bellows 104 is connected to the tail hood 101 through a second flue L2.

[0065] Preferably, the system further comprises a middle wind box 105 and a third flue L3. The front wind box 103 is a wind box of 1 / 3 to 2 / 3 of the head of the sintering machine, the tail wind box 104 is a wind box of 1 / 6 to 1 / 3 of the tail of the sintering machine, and the rest is a middle wind box 105.

[0066] Preferably, the middle wind box 105 is switchably connected to the first flue L1 and the third flue L3. The third flue L3 is connected to the flue gas purification device.

[0067] Preferably, the system further comprises a waste heat utilization device 4. An air outlet is provided in the middle of the vertical precooling device 2, and the air outlet is connected to the air inlet of the waste heat utilization device 4 through the first flue gas delivery pipe G1. The air outlet of the waste heat utilization device 4 is connected to the third flue L3 through the second flue gas delivery pipe G2.

[0068] Preferably, a dust removal device 5 is also provided on the first flue gas conveying duct G1.

[0069] Example 1

[0070] A system for improving the quality of low-quality sintering flue gas by waste heat, the system comprising a sintering machine 1, a vertical precooling device 2, and a ring cooler 3. A tail hood 101 is provided at the rear of the sintering machine 1, and the bottom of the tail hood 101 is connected to the top of the vertical precooling device 2. A crushing and unloading device 102 is provided in the tail hood 101. The ring cooler 3 is arranged below the vertical precooling device 2. A bellows is provided below the sintering machine 1, and the bellows are divided into a front bellows 103 and a rear bellows 104 according to the running direction of the sintering machine. The front bellows 103 is connected to the bottom of the vertical precooling device 2 through a first flue L1. The rear bellows 104 is connected to the tail hood 101 through a second flue L2.

[0071] Example 2

[0072] Example 1 is repeated, except that the system further includes a middle wind box 105 and a third flue L3. The front wind box 103 is a wind box for 2 / 3 of the head of the sintering machine, the rear wind box 104 is a wind box for 1 / 6 of the rear of the sintering machine, and the rest is a middle wind box 105.

[0073] Example 3

[0074] The second embodiment is repeated, except that the middle wind box 105 is switchably connected to the first flue L1 and the third flue L3. The third flue L3 is connected to the flue gas purification device.

[0075] Example 4

[0076] Example 3 is repeated, except that the system further includes a waste heat utilization device 4. An air outlet is provided in the middle of the vertical precooling device 2, and the air outlet is connected to the air inlet of the waste heat utilization device 4 through the first flue gas conveying pipe G1. The air outlet of the waste heat utilization device 4 is connected to the third flue L3 through the second flue gas conveying pipe G2.

[0077] Example 5

[0078] Example 4 is repeated, except that a dust removal device 5 is further provided on the first flue gas conveying duct G1.

[0079] Example 6

[0080] The system described in Example 5 is used to treat the sintering flue gas:

[0081] 1) The sintered material is sintered on the sintering machine, discharged from the crushing and unloading device at the tail of the sintering machine, and enters the vertical pre-cooling device for cooling, and finally enters the ring cooler for cooling. After cooling, the finished sintered ore is obtained;

[0082] 2) There are 21 bellows under the sintering machine. The properties of the flue gas in the bellows are detected. Bellows 1-13 are divided into front bellows, bellows 14-17 are divided into middle bellows, and bellows 18-21 are divided into rear bellows. The rear sintering flue gas is introduced into the crushing and unloading device, where it exchanges heat with the crushed sintered ore. The front sintering flue gas is sent to the vertical precooling device for heat exchange with the sintered ore. After the heat exchange, the front sintering flue gas merges with the rear sintering flue gas and is discharged from the vertical precooling device to obtain high-quality sintering flue gas.

[0083] 3) The high-quality sintering flue gas is sent to the waste heat utilization process after the dust removal process and discharged after the waste heat utilization is completed.

[0084] Example 7

[0085] The system described in Example 5 is used to treat the sintering flue gas:

[0086] 1) The sintered material is sintered on the sintering machine, discharged from the crushing and unloading device at the tail of the sintering machine, and enters the vertical pre-cooling device for cooling, and finally enters the ring cooler for cooling. After cooling, the finished sintered ore is obtained;

[0087] 2) There are 21 bellows under the sintering machine. The properties of the flue gas in the bellows are detected. Bellows 1-13 are divided into front bellows, bellows 14-17 are divided into middle bellows, and bellows 18-21 are divided into rear bellows. The rear sintering flue gas is introduced into the crushing and unloading device, where it exchanges heat with the crushed sintered ore. The front sintering flue gas is sent to the vertical precooling device for heat exchange with the sintered ore. After the heat exchange, the front sintering flue gas merges with the rear sintering flue gas and is discharged from the vertical precooling device to obtain high-quality sintering flue gas.

[0088] 3) The high-quality sintering flue gas is sent to the waste heat utilization process after the dust removal process and discharged after the waste heat utilization is completed.

[0089] 4) Detect the front sintering flue gas flow Q1 = 241100m 3 / h, temperature T1 = 95 °C, rear sintering flue gas flow rate is Q2 = 161700m 3 / h, temperature T2 = 385℃, and detect the temperature in the vertical precooling device. The temperature of the lower part of the vertical precooling device is 537℃, the temperature of the middle part is 714℃, and the temperature of the upper part is 903℃. The temperature in the vertical precooling device meets the requirements. The high-quality flue gas discharged from the vertical precooling device is tested, and the flow rate Q3 = 414900m 3 / h, temperature T3 = 233℃, changing the flow rate of the front sintering flue gas and the rear sintering flue gas, it can be obtained that when the vertical precooling device is in stable operation, the value range of Q3 is 381700~448100m 3 / h, the temperature is 253~216℃.

[0090] 5) The particle size composition and drum strength of the sintered ore discharged from the bottom of the vertical precooling device were detected. The 5-10 mm particle size accounted for 25% of the particle size composition and the drum strength was 71%. By further changing the flow rate of the front sintering flue gas and the rear sintering flue gas, it was found that the 5-10 mm particle size accounted for 20% to 27% of the sintered ore and the drum strength ranged from 68% to 75%. The value range of Q3 was 390000 to 439800 m 3 / h, the temperature is 248~220℃.

[0091] 6) Detect the temperature of high-quality sintering flue gas. If the temperature is lower than 220℃, adjust the flow rate of the front sintering flue gas and the rear sintering flue gas to make the flow rate of high-quality sintering flue gas controlled at 398300~431500m 3 / h, the temperature is controlled at 243~224℃.

Claims

1. A system for improving the quality of low-quality sintering flue gas by waste heat, characterized in that: The system comprises a sintering machine (1), a vertical precooling device (2), and a ring cooler (3); the sintering machine (1) is provided with a tail cover (101) at the rear, and the bottom of the tail cover (101) is connected to the top of the vertical precooling device (2); a crushing and unloading device (102) is arranged in the tail cover (101); the ring cooler (3) is arranged below the vertical precooling device (2); a wind box is provided below the sintering machine (1), and the wind box is divided into a front wind box (103) and a rear wind box (104) according to the running direction of the sintering machine; the front wind box (103) is connected to the bottom of the vertical precooling device (2) through a first flue (L1); and the rear wind box (104) is connected to the tail cover (101) through a second flue (L2).

2. The system according to claim 1, characterized in that: The system also includes a middle wind box (105) and a third flue (L3); the front wind box (103) is a wind box for 1 / 3 to 2 / 3 of the head of the sintering machine, the rear wind box (104) is a wind box for 1 / 6 to 1 / 3 of the tail of the sintering machine, and the rest is a middle wind box (105).

3. The system according to claim 2, characterized in that: The middle wind box (105) is switchably connected to the first flue (L1) and the third flue (L3); the third flue (L3) is connected to the flue gas purification device.

4. The system according to claim 1, characterized in that: The system also includes a waste heat utilization device (4); an air outlet is provided in the middle of the vertical precooling device (2), the air outlet is connected to the air inlet of the waste heat utilization device (4) through a first flue gas conveying pipe (G1); the air outlet of the waste heat utilization device (4) is connected to the third flue (L3) through a second flue gas conveying pipe (G2).

5. The system according to claim 2, characterized in that: The system also includes a waste heat utilization device (4); an air outlet is provided in the middle of the vertical precooling device (2), the air outlet is connected to the air inlet of the waste heat utilization device (4) through a first flue gas conveying pipe (G1); the air outlet of the waste heat utilization device (4) is connected to the third flue (L3) through a second flue gas conveying pipe (G2).

6. The system according to claim 3, characterized in that: The system also includes a waste heat utilization device (4); an air outlet is provided in the middle of the vertical precooling device (2), the air outlet is connected to the air inlet of the waste heat utilization device (4) through a first flue gas conveying pipe (G1); the air outlet of the waste heat utilization device (4) is connected to the third flue (L3) through a second flue gas conveying pipe (G2).

7. The system according to any one of claims 4 to 6, characterized in that: The first flue gas conveying pipeline (G1) is also provided with a dust removal device (5).

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