Recycling system and method for sensible heat of sinter and waste heat of sinter flue gas

Abstract

The application discloses a sinter sensible heat and sinter flue gas waste heat recycling system and method, solves the complex technical problems of the current sinter sensible heat recovery device and flue gas waste heat device, belongs to the sintering waste heat technical field, and the recycling system comprises a sintering machine, a circular cooling kiln and a waste heat power generation device, the sintering machine comprises a sintering trolley and wind boxes arranged in the sintering direction in sequence below the trolley; the circular cooling kiln is used for cooling sinter and is provided with a containing cavity containing sinter, a flue gas air inlet and an air outlet communicated with the containing cavity, the flue gas air inlet is communicated with the last 2-4 wind boxes of the sintering machine; the waste heat power generation device is provided with a cool air outlet and a hot air inlet communicated with the air outlet of the circular cooling kiln; wherein the cool air outlet of the waste heat power generation device is communicated with the air using port of the sintering trolley of the sintering machine, so that the sintering machine, the circular cooling kiln and the waste heat power generation device form a flue gas recycling loop. The recycling system of the application has only one heat exchange structure, is simple in structure, and occupies small space.

Description

Technical Field

[0001] This application belongs to the field of sintering waste heat utilization technology, specifically relating to a recycling system and method for sensible heat of sintered ore and waste heat of sintering flue gas. Background Technology

[0002] Currently, most manufacturers recover the sensible heat of sintered ore separately and the heat of sintering flue gas separately. The sensible heat of sintered ore is exchanged through an annular cooling kiln, and the sintering flue gas is desulfurized and denitrified after heat recovery before being discharged into the atmosphere.

[0003] Both the sensible heat recovery of sintered ore and the heat recovery of sintered flue gas are completed separately, requiring two heat exchange structures, which are complex. Summary of the Invention

[0004] To address the technical problem of numerous and complex waste heat recovery devices in sintering, this application provides a recycling system and method for sensible heat of sintered ore and waste heat of sintering flue gas.

[0005] In a first aspect of this application, a recycling system for sensible heat of sinter and waste heat of sintering flue gas is provided, comprising:

[0006] A sintering machine includes a sintering trolley and a plurality of air boxes arranged sequentially along the sintering direction below the sintering trolley.

[0007] A ring-cooled kiln is used to cool sintered ore and is provided with a receiving cavity for containing sintered ore and a flue gas inlet and outlet connected to the receiving cavity. The flue gas inlet is connected to the last 2-4 air boxes of the sintering machine.

[0008] The waste heat power generation device is equipped with a cool air outlet and a hot air inlet connected to the air outlet of the annular cooling kiln.

[0009] The cool air outlet of the waste heat power generation device is connected to the air inlet of the sintering trolley of the sintering machine, so that the sintering machine, the annular cooling kiln, and the waste heat power generation device form a flue gas recycling loop.

[0010] In some embodiments, the annular cooling furnace includes:

[0011] The kiln body is equipped with chambers;

[0012] An outer sleeve with a gap is provided in the cavity, and the interior of the outer sleeve forms a receiving cavity for sintered ore. The outer sleeve is provided with a first ventilation structure that penetrates the side wall.

[0013] A flue gas conveying pipe is connected to the first ventilation structure, and the portion of the flue gas conveying pipe located outside the kiln body forms the flue gas inlet.

[0014] An exhaust duct is connected to the receiving cavity, and the portion of the exhaust duct located outside the kiln body forms an air outlet.

[0015] In some embodiments, the annular cooling furnace further includes:

[0016] The inner sleeve is coaxially spaced within the outer sleeve, and the space between the inner sleeve and the outer sleeve forms the receiving cavity. The inner sleeve is provided with at least two second ventilation structures arranged vertically at intervals, and the lower second ventilation structure corresponds to the position of the first ventilation structure.

[0017] In some embodiments, there are three of both the second ventilation structure and the first ventilation structure, and the positions of the first ventilation structure and the second ventilation structure correspond one-to-one.

[0018] The second ventilation structure at the bottom is connected to the air source, the two second ventilation structures at the top are connected, the two first ventilation structures at the outermost edge are connected, and the first ventilation structure in the middle is connected to the flue gas conveying duct.

[0019] In some embodiments, the first ventilation structure and the second ventilation structure are both multiple through holes spaced apart and extending through the sidewall, wherein the through holes are axially inclined and their lower ends are close to the receiving cavity.

[0020] In some embodiments, the two uppermost second ventilation structures are connected by a plurality of air ducts, which are spaced apart.

[0021] In some embodiments, the annular cooling furnace further includes:

[0022] The first and second partitions are vertically spaced within the cooling gas chamber between the outer sleeve and the inner wall of the kiln body, so as to divide the cooling gas chamber into partition chambers that correspond one-to-one with the three first ventilation structures. The middle partition chamber is connected to the flue gas conveying pipe, and the two outermost partition chambers are connected to each other.

[0023] The third partition is connected inside the inner sleeve to divide the space inside the inner sleeve into an air cavity that communicates with the lowermost second ventilation structure and the air source, and a connecting cavity that communicates with the two uppermost second ventilation structures.

[0024] In some embodiments, the recycling system includes two induced draft fans, one of which is located between the air box and the flue gas conveying duct, and the other of which is connected to the air source and the second ventilation structure.

[0025] In some embodiments, the recycling system further includes a dust collector located between the air outlet of the sintering machine and the waste heat power generation device.

[0026] In a second aspect of this application, a method for recycling sintering flue gas is provided, applicable to the sintering flue gas recycling system of the first aspect, the recycling method comprising:

[0027] Ambient air enters the second ventilation structure at the bottom and the first ventilation structure at the bottom of the ring cooling kiln in sequence to cool the sintered ore in the containment cavity between the inner sleeve and the outer sleeve in a first-stage manner, thereby obtaining first-stage air.

[0028] The sintering flue gas from the last 2-4 air boxes of the sintering machine enters the first ventilation structure and the second ventilation structure in the middle through the flue gas conveying pipe in sequence, so as to perform secondary cooling of the sinter in the containment cavity and obtain secondary flue gas.

[0029] Second-stage flue gas enters the containment cavity through the uppermost second ventilation structure; first-stage air also enters the containment cavity through the uppermost first ventilation structure. The second-stage flue gas and first-stage air cool the sinter in the containment cavity in three stages and then are discharged through the air outlet. After heat exchange in the waste heat power generation device through the hot air inlet, they are discharged through the cool air outlet to the sintering trolley for recycling.

[0030] According to one or more embodiments of this application, a system for recycling sensible heat of sintered ore and sintering flue gas is provided. The system includes a sintering machine, an annular cooling kiln, and a waste heat power generation device. The sintering machine includes a sintering trolley and multiple air boxes arranged sequentially along the sintering direction below the sintering trolley. The annular cooling kiln is used to cool the sintered ore and is provided with a receiving cavity for containing the sintered ore and a flue gas inlet and outlet connected to the receiving cavity. The flue gas inlet is connected to the last 2-4 air boxes of the sintering machine. The waste heat power generation device is provided with a cool air outlet and a hot air inlet connected to the outlet of the annular cooling kiln. The cool air outlet of the waste heat power generation device is connected to the air outlet of the sintering trolley of the sintering machine, so that the sintering machine, the annular cooling kiln, and the waste heat power generation device form a flue gas recycling loop.

[0031] The sintering machine is used to sinter ore by exhaust gas. The flue gas temperature in the last 2-4 air boxes is about 250-260℃, while the temperature of the sinter entering the ring cooling kiln is about 700-800℃. Therefore, the sintering flue gas can be used as cooling gas to cool the sinter. Furthermore, the flue gas from the last 2-4 wind boxes has a low carbon monoxide content, making it difficult for it to chemically react with iron oxides in the sinter, thus ensuring the chemical properties of the sinter. The annular cooling kiln is used to cool the sinter and transfer the heat from the sinter to the sintering flue gas. The hot sintering flue gas is then sent to the waste heat power generation device for power generation. The temperature of the sintering flue gas after heat exchange with the waste heat power generation device is about 150℃, which still has a certain amount of heat. In addition, the flue gas from the last 2-4 wind boxes has a high oxygen content. Therefore, the sintering flue gas after heat exchange can be used as sintering raw material. It has a high temperature, which reduces the amount of coal to be used in sintering batching, reduces the production cost of sinter, and changes the defect of insufficient heat in the upper material layer and excessive heat in the lower material layer in ordinary sintering, thereby improving the output and quality of sinter.

[0032] Compared to using the sintering flue gas from all the wind boxes for desulfurization and denitrification, this application achieves closed-loop circulation of the flue gas from the last 2-4 wind boxes, reducing the flue gas treatment volume of the desulfurization and denitrification unit and thus lowering its operating costs. Compared to separately recovering the sensible heat of the sinter and the waste heat of the sintering flue gas, this application utilizes an annular cooling kiln to simultaneously recover both the sensible heat of the sinter and the waste heat of the sintering flue gas, achieving two functions in one structure, resulting in a simpler device.

[0033] The recycling system for sensible heat of sinter and waste heat of sintering flue gas provided in this application embodiment has at least the following advantages:

[0034] (1) The flue gas recycling loop formed by the sintering machine, the ring cooler kiln and the waste heat power generation device realizes the recycling of the sintering flue gas of the last 2-4 wind boxes. It has a high oxygen content and a certain amount of heat, which can be used as the air raw material for sintering in the sintering machine. This reduces the amount of flue gas to be treated by the desulfurization and denitrification equipment, alleviates the desulfurization and denitrification treatment pressure, and reduces the operating cost.

[0035] (2) The heat from sintering flue gas and sintered ore is used for waste heat power generation, which improves the utilization rate of heat.

[0036] (3) The sintering flue gas after the waste heat power generation has a certain amount of heat, which can be used as the air raw material for sintering in the sintering machine, reducing the amount of coal in the sintering material, compressing the cost of sintering ore, and improving the physical and chemical properties of sintering ore.

[0037] (4) The ring-cooled kiln is used to simultaneously achieve heat exchange of sensible heat from sintering and sintering flue gas, and the device is simple. Attached Figure Description

[0038] Figure 1A schematic diagram of a recycling system for sensible heat of sintered ore and waste heat of sintering flue gas is shown in an embodiment of this application.

[0039] Figure 2 It shows Figure 1 A schematic diagram of the structure of the ring-cooled kiln in the recycling system.

[0040] Figure 3 for Figure 2 Cross-sectional view of the annular cooling kiln (aa).

[0041] Figure 4 for Figure 2 Cross-sectional view of the annular cooling kiln in the middle.

[0042] Figure 5 for Figure 2 Cross-sectional view of the annular cooling kiln in the middle.

[0043] Figure 6 This diagram illustrates the process steps of a method for recycling sintering flue gas according to an embodiment of this application.

[0044] Explanation of reference numerals in the attached figures:

[0045] 100-Sintering machine; 200-Annular cooling kiln; 211-Containing cavity; 212-Air cavity; 213-Connecting cavity; 214-First partition; 215-Second partition; 216-Third partition; 217-Separation cavity; 220-Kiln body; 230-Outer sleeve; 231-First ventilation structure; 240-Inner sleeve; 241-Second ventilation structure; 250-Flue gas conveying pipe; 270-Air pipe; 300-Waste heat power generation device; 310-Waste heat boiler; 320-Steam power generation device; 400-Dust collector; 500-Induced draft fan. Detailed Implementation

[0046] To enable those skilled in the art to more clearly understand this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0047] Please see Figure 1According to a first aspect of this application, a sintering flue gas recycling system is provided, including a sintering machine 100, an annular cooling kiln 200, and a waste heat power generation device 300. The sintering machine 100 includes a sintering trolley and a plurality of air boxes arranged sequentially along the sintering direction below the sintering trolley. The annular cooling kiln 200 is used to cool sintered ore and is provided with a receiving cavity 211 for containing sintered ore and a flue gas inlet and outlet connected to the receiving cavity 211. The flue gas inlet is connected to the last 2-4 air boxes of the sintering machine 100. The waste heat power generation device 300 is provided with a cool air outlet and a hot air inlet connected to the outlet of the annular cooling kiln 200. The cool air outlet of the waste heat power generation device 300 is connected to the air outlet of the sintering trolley of the sintering machine 100, so that the sintering machine 100, the annular cooling kiln 200, and the waste heat power generation device 300 form a flue gas recycling loop.

[0048] The sintering machine 100 is used for sintering sintered ore by exhaust. The flue gas temperature of its last 2-4 air boxes is about 250-260℃, while the temperature of the sintered ore entering the annular cooling kiln 200 is about 700-800℃. Therefore, the sintering flue gas can be used as cooling gas for the sintered ore. Furthermore, the flue gas from the last 2-4 wind boxes has a low carbon monoxide content, making it difficult for it to chemically react with the iron oxides in the sinter, thus ensuring the chemical properties of the sinter. The annular cooling kiln 200 is used to cool the sinter and transfer the heat from the sinter to the sintering flue gas. The hot sintering flue gas is then sent to the waste heat power generation device 300 to generate electricity. The temperature of the sintering flue gas after heat exchange with the waste heat power generation device 300 is about 130-150℃, which still has a certain amount of heat. In addition, the flue gas from the last 2-4 wind boxes has a high oxygen content. Therefore, the sintering flue gas after heat exchange can be used as sintering raw material. It has a high temperature, thereby reducing the amount of coal to be added during sintering and reducing the production cost of sinter.

[0049] The flue gas recycling loop formed by the sintering machine 100, the ring cooling kiln 200, and the waste heat power generation device 300 realizes the recycling of sintering flue gas from the last 2-4 wind boxes, reducing the flue gas treatment volume of the desulfurization and denitrification equipment and alleviating the desulfurization and denitrification treatment pressure.

[0050] In some embodiments, please combine Figure 2 as well as Figure 4 The annular cooling kiln 200 includes a kiln body 220, an outer sleeve 230, a flue gas conveying pipe 250, and an exhaust pipe. The kiln body 220 is provided with a chamber. The outer sleeve 230 is spaced within the chamber, and the interior of the outer sleeve 230 forms a receiving cavity 211 for sintering. The outer sleeve 230 is provided with a first ventilation structure 231 that penetrates the side wall. The flue gas conveying pipe 250 is connected to the first ventilation structure 231, and the portion of the flue gas conveying pipe 250 located outside the kiln body 220 forms a flue gas inlet. The exhaust pipe is connected to the receiving cavity 211, and the portion of the exhaust pipe located outside the kiln body 220 forms an outlet.

[0051] The annular cooling kiln 200 includes a shell and refractory castable lining the inner wall of the shell. The outer sleeve 230 can be obtained using an annular steel cylinder and refractory castable lining the cylinder. The sinter to be cooled is located in the receiving cavity 211. Flue gas enters the first ventilation structure 231 through the flue gas conveying pipe 250, thereby exchanging heat with the sinter located in the receiving cavity 211. Since the sinter is blocky, there are gaps between different sinters, allowing the flue gas to exit from the receiving cavity 211 to the exhaust pipe through these gaps. In some embodiments, the kiln body 220 has a feed inlet and a discharge outlet respectively connected to the receiving cavity 211. The feed inlet is used for the high-temperature sinter to enter the receiving cavity 211, and the discharge outlet is used for the cooled sinter to exit the annular cooling kiln 200. In some embodiments, the feed inlet is located above the discharge outlet.

[0052] In some embodiments, please combine Figure 2 as well as Figure 5 The annular cooling kiln 200 also includes an inner sleeve 240, which is coaxially spaced within the outer sleeve 230. The space between the inner sleeve 240 and the outer sleeve 230 forms a receiving cavity 211. The inner sleeve 240 is provided with at least two vertically spaced second ventilation structures 241, with the lower second ventilation structure 241 corresponding to the position of the first ventilation structure 231. The flue gas travels through the first ventilation structure 231, the lower second ventilation structure 241, the inner cavity of the inner sleeve 240, and the upper second ventilation structure 241, before being discharged from the receiving cavity 211 to the exhaust pipe, thereby increasing the residence time of the flue gas within the annular cooling kiln 200 and improving heat exchange efficiency.

[0053] To increase the amount of smoke traveling along the path from the first ventilation structure 231, the lower second ventilation structure 241, the inner cavity of the inner sleeve 240, the upper second ventilation structure 241, the receiving cavity 211, and the exhaust duct, and to reduce the amount of smoke traveling along the path from the first ventilation structure 231, the receiving cavity 211, and the exhaust duct, in some embodiments, the vertical distance between the two second ventilation structures 241 is 4-7m, and the radial distance between the corresponding first ventilation structure 231 and the second ventilation structure 241 is 1.5-2.5m, that is, the radial distance between the inner wall of the outer sleeve 230 and the outer wall of the inner sleeve 240 is 1.5-2.5m.

[0054] In some embodiments, please combine Figure 2 as well as Figure 3There are three of each of the second ventilation structure 241 and the first ventilation structure 231. The positions of the first ventilation structure 231 and the second ventilation structure 241 correspond one-to-one. The second ventilation structure 241 located at the bottom is connected to the air source, the two second ventilation structures 241 located at the top are connected, the two first ventilation structures 231 located at the outermost are connected, and the first ventilation structure 231 located in the middle is connected to the flue gas conveying pipe 250.

[0055] A combination of air and sintering flue gas is used to cool the sinter, thereby improving its cooling efficiency. The air path is as follows: the lowermost second ventilation structure 241, the receiving cavity 211, the lowermost first ventilation structure 231, the uppermost first ventilation structure 231, the receiving cavity 211, and the exhaust duct. The flue gas path is as follows: the middle first ventilation structure 231, the receiving cavity 211, the middle second ventilation structure 241, the uppermost second ventilation structure 241, the receiving cavity 211, and the exhaust duct. The air is at room temperature and uses a central intake and external exhaust method for first-stage cooling of the sinter. The air entering from the center has a fast flow rate, shortening the time it takes to reach the second ventilation structure 241. The air diffuses from the smaller central section to the larger external section, reducing its velocity and extending the heat exchange time between the air and the sinter, resulting in high cooling efficiency. After undergoing the first-stage heat exchange, the temperature of the first-stage air is approximately 100-120°C. It moves towards the uppermost first ventilation structure 231, where it exchanges heat with the flue gas. The temperature of the first-stage air rises to approximately 200°C and then enters the containment cavity 211 through the uppermost first ventilation structure 231. Because the temperature of the flue gas is relatively high, it undergoes a second-stage heat exchange with the sinter in the middle, which is at approximately 250°C. The second-stage flue gas then enters the containment cavity 211 from the uppermost second ventilation structure 241 and mixes with the first-stage air to perform a third-stage cooling on the uppermost sinter. At this position, the temperature of the second-stage flue gas is relatively close to that of the first-stage air, which can improve the heat exchange efficiency of the third-stage cooling.

[0056] In some embodiments, please combine Figure 2 The first ventilation structure 231 and the second ventilation structure 241 are both multiple through holes that are spaced apart and penetrate through the side wall. The through holes are axially inclined and their lower ends are close to the receiving cavity 211 to prevent the sintered ore in the receiving cavity 211 from moving out of the outer sleeve 230 along the through holes.

[0057] In some embodiments, please continue to combine Figure 2 The two uppermost second ventilation structures 241 are connected by multiple air ducts 270. The multiple air ducts 270 are spaced apart and are located in the space between the outer sleeve 230 and the inner wall of the kiln body 220, which improves the heat exchange efficiency between the flue gas and the first-order air.

[0058] In some embodiments, please continue to combine Figure 2 The annular cooling kiln 200 also includes a first partition 214, a second partition 215, and a third partition 216. The first partition 214 and the second partition 215 are vertically spaced within the cooling gas chamber between the outer sleeve 230 and the inner wall of the kiln body 220, dividing the cooling gas chamber into partition chambers that are connected to three first ventilation structures 231 in a one-to-one manner. The middle partition chamber is connected to the flue gas conveying pipe 250, and the two outermost partition chambers are interconnected. The third partition 216 is connected to the inner sleeve 240, dividing the space within the inner sleeve 240 into an air chamber 212 that is connected to the lowermost second ventilation structure 241 and the air source, and a connecting chamber 213 that is connected to the two uppermost second ventilation structures 241. The first partition 214, the second partition 215, and the third partition 216 can be made of steel plates.

[0059] In some embodiments, the two outermost partition chambers are connected by an air duct 270 located in the middle partition chamber. The flue gas in the middle partition chamber can exchange heat with the first-order air in the air duct 270 to reduce the temperature of the flue gas and achieve third-order heat exchange.

[0060] In some embodiments, the partition cavity and the receiving cavity are both annular, and the first ventilation structure and the second ventilation structure are both arranged in annular order.

[0061] In some embodiments, please combine Figure 1 The recycling system includes two induced draft fans 500. One induced draft fan 500 is located between the air box and the flue gas conveying pipe 250 to smoothly guide the sintering flue gas discharged from the air box into the flue gas conveying pipe; the other induced draft fan 500 is connected to the air source and the second ventilation structure 241 to introduce ambient temperature air into the annular cooling kiln 200.

[0062] In some embodiments, please continue to combine Figure 1 The recycling system also includes a dust collector 400 located between the air outlet of the sintering machine 100 and the waste heat power generation unit 300 to remove dust from the flue gas. The dust collector 400 can be a bag filter or an electrostatic precipitator; this application makes no restriction.

[0063] Please continue to combine Figure 1 The waste heat power generation device 300 includes a waste heat boiler 310 and a steam power generation device 320, which is prior art, and its details are not elaborated here. The waste heat boiler 310 is provided with a cool air outlet and a hot air inlet connected to the air outlet of the annular cooling kiln 200.

[0064] Please see Figure 6According to a second aspect of this application, a method for recycling sensible heat of sinter and sintering flue gas is provided, applicable to the recycling system for sensible heat of sinter and sintering flue gas of the first aspect. The recycling method includes:

[0065] S1. Normal temperature air enters the second ventilation structure 241 and the first ventilation structure 231 at the bottom of the ring cooling kiln 200 in sequence to cool the sintered ore in the accommodating cavity 211 between the inner sleeve 240 and the outer sleeve 230 in the first stage, and obtains first-stage air.

[0066] S2. The sintering flue gas from the last 2-4 air boxes of the sintering machine 100 enters the first ventilation structure 231 and the second ventilation structure 241 in the middle through the flue gas conveying pipe 250 in a second-stage cooling of the sinter in the receiving cavity 211 to obtain second-stage flue gas.

[0067] The volume fraction of oxygen in the sintering flue gas of the last 2-4 air boxes of the sintering machine 100 is about 15-20%, and the volume fraction of carbon monoxide is about 0.2%. The high oxygen content is suitable for exhaust sintering, while the low carbon monoxide content ensures that the carbon monoxide will not react chemically with the sinter when it is cooled in the annular cooling kiln 200, thus guaranteeing the chemical properties of the sinter.

[0068] Table 1. Main chemical composition of sintering flue gas from the last 2-4 air boxes of a sintering machine 100 Volume fraction / % 18.5 78.5 1.5 0.2 0.013 0.003 0.001

[0069] S3. Second-stage flue gas enters the containment cavity 211 through the uppermost second ventilation structure 241; first-stage air also enters the containment cavity 211 through the uppermost first ventilation structure 231. The second-stage flue gas and first-stage air cool the sinter in the containment cavity 211 in three stages and then are discharged through the air outlet. After heat exchange in the waste heat power generation device 300 through the hot air inlet, they are discharged through the cool air outlet to the sintering trolley for recycling.

[0070] The two gases are combined, with air providing first-stage cooling to the sinter and flue gas providing second-stage cooling. The first-stage air and second-stage flue gas are then mixed together to provide third-stage cooling to the sinter, thus improving the cooling efficiency of the sinter.

[0071] In some embodiments, the volume fraction ratio of air to flue gas is 1:1 (standard state), which improves both the cooling effect of sinter and the recovery rate of flue gas.

[0072] The sensible heat of sinter and waste heat of sintering flue gas recycling system provided in this application, using a three-stage two-gas ring-cooled kiln 200, taking a 200-square-meter sintering machine 100 as an example, requires an investment of approximately 50 million yuan for the entire system, and reduces sintering flue gas emissions by 25-30% (~300,000 m³). 3With reduced flue gas treatment volume ( / h operating condition), the pressure on desulfurization and denitrification is reduced, thus reducing the flue gas emissions from the blast furnace; waste heat power generation is 35-40 kWh / t of sinter, with an annual power generation of approximately 85 million kWh / year, which reduces carbon dioxide emissions by 82,500 tons / year compared to fuel combustion power generation; the solid fuel (coke powder, coal) per ton of sinter is reduced by 3-5 kg, which, calculated at 3 kg, saves approximately 8,000 tons / year of solid fuel; the FeO content of sinter is reduced by 2-3%, and the sinter grade increases due to the reduction in solid fuel, resulting in a higher sinter yield, which is very beneficial to downstream ironmaking production; the physical heat introduced by hot air sintering replaces part of the heat generated by solid fuel combustion, completely changing the problem of insufficient heat in the upper part and excessive heat in the lower part of the ordinary sintering bed, improving the yield and quality of sinter, and reducing the FeO content of sinter, etc.

[0073] The sinter sensible heat and sinter flue gas recycling system provided in this application embodiment has at least the following advantages:

[0074] (1) The flue gas recycling loop formed by the sintering machine 100, the ring cooling kiln 200, and the waste heat power generation device 300 realizes the recycling of the sintering flue gas of the last 2-4 wind boxes. It has a high oxygen content and a certain amount of heat, and can be used as the air raw material for sintering in the sintering machine 100. This part of the sintering flue gas does not need to be desulfurized and denitrified, which reduces the flue gas treatment volume of the desulfurization and denitrification equipment, reduces the pressure of desulfurization and denitrification treatment, and reduces the operating cost.

[0075] (2) The heat from sintering flue gas and sintered ore is used for waste heat power generation, which improves the utilization rate of heat.

[0076] (3) The sintering flue gas after the waste heat power generation has a certain amount of heat, which can be used as the air raw material for sintering in sintering machine 100, reducing the amount of coal in the sintering material, compressing the cost of sintering ore, and improving the chemical properties of sintering ore.

[0077] (4) The ring-cooled kiln is used to simultaneously achieve heat exchange of sensible heat from sintering and sintering flue gas, and the device is simple.

[0078] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0079] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the 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 application.

[0080] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0081] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0082] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A system for recycling the sensible heat of sintered ore and the waste heat of sintering flue gas, characterized in that, include: A sintering machine includes a sintering trolley and a plurality of air boxes arranged sequentially along the sintering direction below the sintering trolley. An annular cooling kiln, used for cooling sintered ore, includes a kiln body, an outer sleeve, an inner sleeve, a first baffle, a second baffle, a third baffle, a flue gas conveying pipe, and an exhaust pipe. The kiln body has a chamber, and the outer sleeve is positioned within this chamber. The outer sleeve has three first ventilation structures penetrating its sidewalls. The inner sleeve is coaxially positioned within the outer sleeve and has three second ventilation structures spaced vertically. The positions of the first and second ventilation structures correspond one-to-one. The space between the inner and outer sleeves forms a receiving cavity for the sintered ore. The first and second baffles are vertically spaced within the cooling gas cavity between the outer sleeve and the inner wall of the kiln body. The cooling gas chamber is divided into partition chambers that correspond one-to-one with the three first ventilation structures. The middle partition chamber is connected to the flue gas conveying pipe, and the two outermost partition chambers are interconnected. The third partition is connected to the inner sleeve to divide the space inside the inner sleeve into an air chamber connected to the lowermost second ventilation structure and the air source, and a connecting chamber connected to the two uppermost second ventilation structures to improve heat exchange efficiency. The portion of the flue gas conveying pipe outside the kiln body forms a flue gas inlet. The exhaust pipe is connected to the receiving cavity, and the portion of the exhaust pipe outside the kiln body forms an exhaust outlet. The flue gas inlet is connected to the last 2-4 air boxes of the sintering machine. The waste heat power generation device is equipped with a cool air outlet and a hot air inlet connected to the air outlet of the annular cooling kiln; the cool air outlet of the waste heat power generation device is connected to the air outlet of the sintering trolley of the sintering machine, so that the sintering machine, the annular cooling kiln and the waste heat power generation device form a flue gas recycling loop.

2. The recycling system for sensible heat of sinter and waste heat of sintering flue gas as described in claim 1, characterized in that, Both the first ventilation structure and the second ventilation structure are multiple through holes spaced apart and extending through the sidewall. The through holes are axially inclined and their lower ends are close to the receiving cavity.

3. The recycling system for sensible heat of sintered ore and waste heat of sintering flue gas as described in claim 1, characterized in that, The two uppermost second ventilation structures are connected by multiple air ducts, which are spaced apart.

4. The recycling system for sensible heat of sinter and waste heat of sintering flue gas as described in any one of claims 1-3, characterized in that, The recycling system includes two induced draft fans, one of which is located between the air box and the flue gas conveying duct, and the other is connected to the air source and the second ventilation structure.

5. The recycling system for the sensible heat of sinter and the waste heat of sintering flue gas as described in any one of claims 1-3, characterized in that, The recycling system also includes a dust collector located between the air outlet of the sintering machine and the waste heat power generation device.

6. A method for recycling the sensible heat of sintered ore and the waste heat of sintering flue gas, applicable to the recycling system for the sensible heat of sintered ore and the waste heat of sintering flue gas as described in any one of claims 1-5, characterized in that, The recycling method includes: Ambient air enters the second ventilation structure at the bottom and the first ventilation structure at the bottom of the ring cooling kiln in sequence to cool the sintered ore in the containment cavity between the inner sleeve and the outer sleeve in a first-stage manner, thereby obtaining first-stage air. The sintering flue gas from the last 2-4 air boxes of the sintering machine enters the first ventilation structure and the second ventilation structure in the middle through the flue gas conveying pipe in sequence, so as to perform secondary cooling of the sinter in the containment cavity and obtain secondary flue gas. Second-stage flue gas enters the containment cavity through the uppermost second ventilation structure; first-stage air also enters the containment cavity through the uppermost first ventilation structure. The second-stage flue gas and first-stage air cool the sinter in the containment cavity in three stages and then are discharged through the air outlet. After heat exchange in the waste heat power generation device through the hot air inlet, they are discharged through the cool air outlet to the sintering trolley for recycling.

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