Multistage efficient lump ore drying system

Abstract

The invention relates to a lump ore multi-stage efficient drying system which is characterized by comprising a first-stage hot air assembly, a second-stage hot air assembly, a third-stage hot air assembly and a belt type trolley. The head end of the belt type trolley is used for receiving lump ore falling from the stock bin; a conveying belt is arranged below the belt type trolley; lump ore is conveyed to the tail end from the head end of the belt type trolley by the belt type trolley and falls on the conveying belt. According to the lump ore multi-stage efficient drying system, a three-stage drying mode is adopted, different types of heat sources are adopted according to different drying requirements, consumption of coal gas can be reduced, waste gas waste heat with low additional value is utilized, and the lump ore drying energy cost is reduced; the thickness of a lump ore drying ore bed can be increased, the problem that the drying degree of the ore bed is not uniform from top to bottom is solved through the design of the flow divider, efficient drying conditions are created, and the production efficiency is improved.

Description

Technical Field

[0001] This invention relates to a multi-stage high-efficiency drying system for lump ore, belonging to the field of metal smelting technology. Background Technology

[0002] In the structure of blast furnace smelting charge, it is generally composed of sinter, pellets and lump ore. Sinter and pellets are processed from mineral powder and are called clinker. Lump ore is raw material of a certain particle size formed after ore is crushed. Generally, the unit price of lump ore is about 150 yuan / ton cheaper than that of sinter. Therefore, using lump ore in blast furnaces is a major cost reduction method.

[0003] Currently, the proportion of lump ore used in blast furnaces is generally between 15% and 18%. Further increases in the proportion of lump ore are limited by its moisture content and fines content. High moisture content leads to a waste of valuable heat in the blast furnace, while excessive fines content affects its permeability. Before use, lump ore undergoes washing or cold screening to reduce its fines content. Washing is rarely used by companies due to its high moisture content. Cold screening efficiency is closely related to the moisture content of the lump ore; high moisture content results in lower screening efficiency, especially in winter when moisture content in lump ore easily causes caking, making screening even more difficult.

[0004] Therefore, in order to increase the proportion of lump ore and reduce production costs, the industry has begun to implement lump ore drying technology. There are two main problems with lump ore drying: First, the problem of drying uniformity. When using forced draft or forced draft methods, the flue gas temperature in contact with the surface lump ore is higher, resulting in faster moisture reduction, while the bottom lump ore dries more slowly and has a higher moisture content. Extending the drying time increases gas costs and reduces efficiency. Therefore, forced draft drying is generally suitable for thin-layer drying, while forced draft is suitable for thick-layer drying. Second, the problem of lump ore cracking and mechanical crushing. When using a rotary kiln to dry lump ore, the ore is easily crushed by impact during its journey, producing new powder. Similarly, when using a belt grate for forced draft or forced draft drying, if the temperature exceeds 350℃, the crystal water in the lump ore will evaporate due to heat, causing the lump ore to crack and produce new powder, also damaging the particle size. Both methods negatively impact the original particle size of the lump ore. The powder formed from the lump ore, as a raw material for sintering, has a unit price about 100 yuan / ton lower than that of blast furnace lump ore. Therefore, the formation of new powder means quality loss and thus economic loss.

[0005] Based on currently available patents and literature searches, patent application number 202310849348.7 discloses a microwave composite flue gas drying process for blast furnace ore feed, employing a ring-shaped belt dryer superimposed with microwave heating to achieve effective drying of the ore. The heating method is blast ventilation, with a flue gas temperature of 220℃. Its drawback is that the ore layer thickness cannot be too thick, and improving system efficiency mainly relies on increasing the operating speed. The main problem with microwave heating is the high cost of the heat source. Patent application number 202311698455.0 discloses a drying device for blast furnace ore and coke feed, utilizing the high-temperature flue gas generated during dust removal in the blast furnace tapping area to dry the ore and coke. The heat source for this scheme is the flue gas generated during dust removal in the tapping area, which is only available during the tapping process, making the heat source unstable. Patent application number 202310419794... .4 discloses a device and method for reducing the moisture and powder content of blast furnace lump ore, proposing a combined operation of blast furnace lump ore drying and sintering processes. A wire mesh belt conveyor is arranged above the sintering machine to efficiently utilize the heat of high-temperature circulating flue gas for drying and screening of the lump ore. The problem is that a flue gas circulation process is required, and most sintering machines in China have not been modified for this purpose. This process is currently controversial and has a certain impact on the sintering process. Furthermore, arranging the conveyor belt on the sintering machine material surface significantly affects the normal maintenance and operation space of the sintering trolley. Finally, the dust generated by the direct blowing of circulating flue gas onto the lump ore can easily cause environmental problems. This invention mainly addresses the problem of uneven drying caused by excessively thick lump ore layers in the belt trolley drying process, as well as the problems of low drying efficiency below the lump ore bursting temperature and reduced lump ore particle size above the bursting temperature. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the above-mentioned technologies and provide a multi-stage high-efficiency drying system for lump ore that uses multi-level hot flue gas to dry lump ore, achieves efficient and low-consumption drying of lump ore, and does not damage the particle size of lump ore, thereby creating conditions for increasing the proportion of lump ore in blast furnaces and reducing production costs.

[0007] To solve the above-mentioned technical problems, the technical solution proposed by the present invention is: a multi-stage high-efficiency drying system for lump ore, comprising: a primary hot air assembly, a secondary hot air assembly, a tertiary hot air assembly, and a belt trolley; The head end of the belt trolley receives the ore chunks falling from the silo; a conveyor belt is located below the belt trolley; the ore chunks are transported from the head end of the belt trolley to the tail end and fall onto the conveyor belt. The primary hot air assembly, the secondary hot air assembly, and the tertiary hot air assembly are arranged sequentially above the belt trolley along the extension direction of the belt trolley. The primary hot air assembly includes a blower, a gas combustion chamber, and a first gas collection hood connected in sequence; the opening of the first gas collection hood faces the belt trolley. The secondary hot air assembly includes a connected secondary induced draft fan and a second gas collection hood; the opening of the second gas collection hood faces the belt trolley; the second induced draft fan is connected to a medium-temperature flue gas source. The three-stage hot air assembly includes a connected three-stage induced draft fan and a third gas collection hood; the opening of the third gas collection hood faces the belt trolley; the third induced draft fan is connected to a low-temperature flue gas source; A first diverter is provided between the primary hot air assembly and the secondary hot air assembly; a second diverter is provided between the secondary hot air assembly and the tertiary hot air assembly; both the first and second diverters include a middle partition, two side partitions, and a bottom plate; the middle partition is vertically arranged, the two side partitions are fixed to both sides of the middle partition, and the bottom plate is fixed to the bottom of the middle partition and the two side partitions, with the two side partitions extending to the two side edges of the belt trolley respectively; the height of the bottom plate of the first diverter is lower than the upper surface of the block ore on the belt trolley; the height of the bottom plate of the second diverter is lower than the bottom plate of the first diverter.

[0008] A further improvement to the above scheme is that: the edge of the belt trolley, corresponding to the position of the first and second diverters, has a discharge port; a chute is provided below the discharge port; the chute faces the conveyor belt.

[0009] A further improvement to the above solution is that a buffer chamber is provided between the chute and the conveyor belt.

[0010] A further improvement to the above scheme is that blast furnace gas is introduced into the gas combustion chamber, and air is blown in by the blower to produce flue gas at 300 to 350 degrees Celsius.

[0011] A further improvement to the above scheme is that the medium-temperature flue gas source is the exhaust gas from the low-temperature section of the sintering machine's ring cooler or the tail gas from the blast furnace's hot blast stove, which is flue gas at 200 to 250 degrees Celsius.

[0012] A further improvement to the above scheme is that the low-temperature flue gas source is the exhaust gas from the chimney after sintering SCR denitrification or the exhaust gas from the sintering large flue, which is flue gas at 100 to 150 degrees Celsius.

[0013] A further improvement to the above solution is that it also includes an exhaust gas extraction and dust removal assembly that covers the dust removal range of the belt trolley; the exhaust gas extraction and dust removal assembly includes an exhaust fan and a bag filter connected to each other; the bag filter is connected to a duct extending along the belt trolley; the duct has a plurality of air boxes facing the belt trolley.

[0014] The further improvement of the above scheme is as follows: the middle partition of the first and second splitters is fixed to the crossbeam with fastening bolts; the included angle between the middle partition and the two side partitions is 120 degrees; the middle partition and the two side partitions are made of ordinary carbon steel, with a thickness of 40 mm and a height of 400 mm; the bottom plate is made of 316L stainless steel, the included angle between the bottom plate and the horizontal is 15°, and the front end of the bottom plate is arc-shaped with an arc of 0.4 to 0.6 rad.

[0015] The multi-stage high-efficiency drying system for lump ore provided by this invention adopts a three-stage drying method. Different types of heat sources are used according to different drying requirements, which can reduce the consumption of coal gas, make use of low-value-added waste heat, and reduce the energy cost of lump ore drying. It can increase the thickness of the lump ore drying layer and solve the problem of uneven drying from top to bottom of the ore layer through the design of the diverter, creating conditions for high-efficiency drying and improving production efficiency. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a preferred embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of the splitter structure.

[0018] Figure 3 This is a front view schematic diagram of the splitter structure.

[0019] Figure 4 This is a top view of the splitter's structure.

[0020] Figure 5 This is a side view of the splitter structure. Detailed Implementation

[0021] Example: The multi-stage high-efficiency drying system for lump ore in this example, such as... Figure 1 As shown, it includes: a primary hot air assembly, a secondary hot air assembly, a tertiary hot air assembly, and a belt trolley 15.

[0022] The hopper 1 is located above the head end of the belt trolley 15. Lump ore falls from the hopper 1, passes through the swing screen 8, and lands on the belt trolley 15. The belt trolley 15 then transports the lump ore from the head end to the tail end, where it falls into the ore trough 27 and then enters the conveyor belt 29 via the plate feeder 28. The belt trolley 15 has baffles 10 on both sides, but the baffles 10 are not connected to the belt trolley 15.

[0023] The primary, secondary, and tertiary hot air assemblies are arranged sequentially above the belt trolley along its extension direction. A first diverter 11 is located between the primary and secondary hot air assemblies; a second diverter 13 is located between the secondary and tertiary hot air assemblies. The first diverter 11 and the second diverter 13 are positioned at the midpoint of the width of the belt trolley 15.

[0024] The first splitter 11 and the second splitter 13 have identical structures; therefore, the first splitter 11 will be used as an example for explanation. Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the diverter includes a central partition 33, two side partitions 34, and a bottom plate 35. The central partition 33 is vertically mounted on a crossbeam 31 by bolts 32. The two side partitions 34 are welded to both sides of the central partition 33, with an angle of 120 degrees between the central partition 33 and the two side partitions 34. The three components form a "V" shape when viewed from above. The bottom plate 35 is welded to the bottom of the central partition 33 and the two side partitions 34. The central partition and the two side partitions are made of ordinary carbon steel, with a thickness of 40 mm and a height of 400 mm. The bottom plate is made of 316L stainless steel, with an angle of 15° to the horizontal to facilitate the rolling of ore blocks. The front end of the bottom plate is arc-shaped with an arc of 0.4 to 0.6 rad to reduce wear on the bottom plate from ore blocks. The two side partitions 34 extend to the two side edges of the belt trolley 15, respectively. The two side edges of the belt trolley 15 are respectively provided with discharge ports corresponding to the first diverter 11 and the second diverter 13. Below the discharge port of the first diverter is a first chute 16, and below the discharge port of the second diverter is a second chute 17. The length of both ends of the chute is 100 to 200 mm longer than the length of the discharge port to prevent spillage. Below the first chute 16 is a first buffer chamber 22, and below the second chute is a second buffer chamber 24. The height of the bottom plate of the first diverter 11 is 200 to 300 mm lower than the upper surface of the lump ore on the belt trolley 15; the height of the bottom plate of the second diverter 13 is 200 to 300 mm lower than the bottom plate of the first diverter 11. The heights of the first diverter 11 and the second diverter 13 can be adjusted using bolts 32.

[0025] The primary hot air assembly includes a blower 3, a gas combustion chamber 2, and a first gas collection hood 9 connected in sequence; the opening of the first gas collection hood 9 faces the belt trolley 15; the gas combustion chamber 2 introduces blast furnace gas, and the blower 3 blows in air to produce flue gas at 300 to 350 degrees Celsius.

[0026] The secondary hot air assembly includes a connected secondary induced draft fan 4 and a second gas collecting hood 12; the opening of the second gas collecting hood 12 faces the belt trolley 15; the second induced draft fan 4 is connected to a medium-temperature flue gas source 5; the medium-temperature flue gas source is the exhaust gas from the low-temperature section of the sintering machine ring cooler or the tail gas from the blast furnace hot blast stove, which is flue gas at 200 to 250 degrees Celsius.

[0027] The three-stage hot air assembly includes a connected three-stage induced draft fan 6 and a third gas collection hood 14; the opening of the third gas collection hood 14 faces the belt trolley 15; the third induced draft fan 6 is connected to a low-temperature flue gas source 7; the low-temperature flue gas source is the exhaust gas from the chimney after sintering SCR denitrification or the exhaust gas from the sintering large flue, which is flue gas at 100 to 150 degrees Celsius.

[0028] The multi-stage high-efficiency drying system for lump ore in this embodiment also includes an exhaust gas extraction and dust removal assembly that covers the belt trolley; the exhaust gas extraction and dust removal assembly includes an exhaust fan 18 and a bag filter 19 connected to each other; the bag filter 19 is connected to a duct 20 extending along the belt trolley; the duct 20 has air boxes 21, 23 and 24 facing the belt trolley, so that the extraction range covers the belt trolley.

[0029] The multi-stage high-efficiency drying system for lump ore in this embodiment can dry materials with a drying layer thickness of 600mm to 800mm.

[0030] Lump ore is fed from silo 1 onto belt trolley 15 via screen 8. As belt trolley 15 moves, it is heated by hot air from the primary hot air assembly, reducing surface moisture content. Continuing on belt trolley 15, the ore is diverted to the first diverter 11, where the surface ore is directed to the first chute 16 and then to conveyor belt 29. The remaining ore continues on belt trolley 15 to the secondary hot air assembly for further heating, then to the second diverter 13, where the surface ore is diverted to the second chute 17 and then to conveyor belt 29. Finally, the remaining ore continues on belt trolley 15 to the tertiary hot air assembly for further heating. It then falls into ore bin 27, passes through plate feeder 28, and enters conveyor belt 29. The ore on conveyor belt 29 is then fed to screening device 30, which screens all the ore to remove powder, resulting in high-quality ore for blast furnace smelting. This completes the entire ore drying process. The secondary and tertiary drying processes use steel plant exhaust gas as a heat source, which can significantly reduce system energy consumption.

[0031] This invention is not limited to the products described above. All technical solutions derived using equivalent substitutions fall within the scope of protection claimed by this invention.

Claims

1. A multi-stage efficient drying system for lump ore, characterized in that, The application relates to a hot air supply device for a sintering machine. The device comprises a primary hot air supply assembly, a secondary hot air supply assembly, a tertiary hot air supply assembly and a belt trolley. The belt trolley receives block ores dropped from a stock bin at a head end thereof, and has a conveying belt below the belt trolley. The block ores are conveyed by the belt trolley from the head end to a tail end and dropped on the conveying belt. The primary hot air supply assembly, the secondary hot air supply assembly and the tertiary hot air supply assembly are arranged above the belt trolley along the extension direction of the belt trolley. The primary hot air supply assembly comprises a blower, a coal gas combustion chamber and a first gas collecting hood connected in sequence. The first gas collecting hood has an opening facing the belt trolley. The secondary hot air supply assembly comprises a secondary air blower and a second gas collecting hood connected in sequence.

2. The lump ore multi-stage high-efficiency drying system according to claim 1, characterized in that: The second gas collecting hood has an opening facing the belt trolley.

3. The lump ore multi-stage high-efficiency drying system according to claim 2, characterized in that: The secondary air blower is connected to a medium-temperature flue gas source.

4. The lump ore multi-stage high-efficiency drying system according to claim 1, characterized in that: The tertiary hot air supply assembly comprises a tertiary air blower and a third gas collecting hood connected in sequence.

5. The lump ore multi-stage high-efficiency drying system according to claim 4, characterized in that: The third gas collecting hood has an opening facing the belt trolley.

6. The lump ore multi-stage high-efficiency drying system according to claim 5, characterized in that: The tertiary air blower is connected to a low-temperature flue gas source.

7. The lump ore multi-stage high-efficiency drying system according to claim 6, characterized in that: The primary hot air supply assembly and the secondary hot air supply assembly are provided with a first flow divider.

8. The lump ore multi-stage high-efficiency drying system according to claim 1, characterized in that: The secondary hot air supply assembly and the tertiary hot air supply assembly are provided with a second flow divider. The first flow divider and the second flow divider each comprise an intermediate partition plate, two side partition plates and a bottom plate. The intermediate partition plate is vertically arranged. The two side partition plates are fixed on the two sides of the intermediate partition plate. The bottom plate is fixed on the bottom of the intermediate partition plate and the two side partition plates. The two side partition plates respectively extend to the two side edges of the belt trolley. The height of the bottom plate of the first flow divider is lower than the upper surface of the block ores on the belt trolley. The height of the bottom plate of the second flow divider is lower than the bottom plate of the first flow divider. The edges of the belt trolley corresponding to the positions of the first flow divider and the second flow divider are provided with discharge ports. The lower part of the discharge port is provided with a chute. The chute is arranged between the chute and the conveying belt. The coal gas combustion chamber is connected to a blast furnace gas source. The blower is connected to an air source. The flue gas generated by the blower is at a temperature of 300-350 DEG C. The medium-temperature flue gas source is the low-temperature section exhaust gas of a sintering machine or the tail gas of a blast furnace hot blast stove. The low-temperature flue gas source is the chimney exhaust gas after SCR denitration of the sintering machine or the large flue exhaust gas of the sintering machine. The device further comprises an exhaust gas suction and dust removal assembly covering the belt trolley. The exhaust gas suction and dust removal assembly comprises a suction blower and a bag-type dust collector connected in sequence. The bag-type dust collector is connected to a pipeline extending along the belt trolley. The pipeline is provided with a plurality of bellows facing the belt trolley. The intermediate partition plate of the first flow divider and the second flow divider is fixed to a cross beam by fastening bolts. The included angle between the intermediate partition plate and the two side partition plates is 120 DEG. The intermediate partition plate and the two side partition plates are made of plain carbon steel and have a thickness of 40 mm and a height of 400 mm. The bottom plate is made of 316L stainless steel. The included angle between the bottom plate and the horizontal direction is 15 DEG. The front end of the bottom plate is in a circular arc shape and has an arc degree of 0.4-0.6 rad.

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