Direct reduction iron material pneumatic conveying method and system

Abstract

The present application relates to the technical field of pneumatic conveying, in particular to a hot direct reduction iron material pneumatic conveying method and system. The conventional gas pipeline conveying method is used to convey the HRDI material into the electric arc furnace by pneumatic conveying, and the equipment is prone to wear and breakage. In view of the above problems, the present application provides a hot direct reduction iron material pneumatic conveying method. The axis of the bottom three inclined pipe elbow sections of the plug sender structure is designed to form an angle of not more than 20° with the axis of the straight pipe section in the opposite direction of the material conveying, and the combined action of the pulse gas source valve group and the plug gas source valve group forms discontinuous material plugs in the conveying pipeline, which significantly reduces the abrasion of the conveying pipeline inner wall caused by the material in the pneumatic conveying process, and the blocking and crushing phenomenon of the hot direct reduction iron material in the conveying pipeline.

Description

Technical Field

[0001] This invention relates to the field of pneumatic conveying technology, specifically to a pneumatic conveying method and system for direct thermal reduction of iron materials. Background Technology

[0002] Direct reduced iron (DRI) is a high-quality feedstock for electric arc furnaces and converters, suitable for producing high-quality and special steels. Because DRI smelting does not require coke, it is a high-quality, low-consumption, and low-pollution new ironmaking process, and one of the world's leading technologies in steelmaking.

[0003] Using hot charging and hot delivery of direct reduced iron (DRI) is an important measure to reduce the energy consumption of electric arc furnaces. Research results show that when DRI replaces scrap steel in electric arc furnace smelting, for every 100°C increase in the DRI charging temperature, approximately 25 kWh of energy can be saved per ton of steel. When using hot DRI charging at approximately 700°C, the energy consumption per ton of steel is reduced by 110-160 kWh compared to cold DRI / HBI smelting, the smelting time can be reduced by 10-20% (approximately 10-15 minutes), and the electric arc furnace capacity can be increased by more than 15%.

[0004] Directly feeding hot direct reduced iron into an electric arc furnace for smelting can significantly reduce power consumption and increase the production capacity of the electric arc furnace, providing conditions for further reducing energy consumption in the production of hot direct reduced iron (HRDI) (600-700℃) in vertical shaft furnaces – a short process using electric arc furnaces.

[0005] In recent years, most newly built gas-based vertical shaft furnace direct reduced iron (DRI)-electric arc furnace steelmaking production lines have adopted the DRI hot discharge, hot conveying, and hot charging electric arc furnace process. Based on the principle of "lowest energy consumption and simplest conveying equipment," the main methods for achieving industrial-scale DRI hot conveying include: gas pipeline conveying; hot conveyor method; and insulated tank method.

[0006] Gas pipeline transportation uses hot coal gas or hot nitrogen as the transport gas and employs a closed pipeline system to transport hot direct reduced iron (HDRI). The process layout of gas-based vertical shaft furnaces and electric furnaces is relatively flexible and convenient, and requires less land area; however, the maximum transport distance of this method is ≤200m, and it suffers from problems such as easy equipment wear, easy material jamming, easy breakage, and high energy consumption. Summary of the Invention

[0007] The existing technology has the problem that conventional gas pipeline conveying methods for pneumatically conveying HRDI material into electric arc furnaces suffer from equipment wear and breakage. To address these issues, this invention provides a method for pneumatically conveying HRDI material, comprising the following steps:

[0008] (1) Simultaneously open the discharge gate valve at the bottom of the gas-based vertical shaft furnace and the upper bell valve of the feeder to start feeding the feeder. The hot direct reduction iron material enters the feeder through the discharge chute. When the hot direct reduction iron material in the feeder reaches the set feed rate, close the discharge gate valve at the bottom of the gas-based vertical shaft furnace and the upper bell valve of the feeder.

[0009] (2) Open the lower bell valve of the feeder to add all the material in the feeder into the hot direct reduction iron transmitter, then close the lower bell valve of the feeder and simultaneously execute step (1).

[0010] (3) The hot direct reduced iron generator includes an upper storage tank and a bolt generator that are interconnected vertically. The volume of material in the upper storage tank is not less than 1 / 2. The material does not completely fill the upper storage tank. After the material enters the hot direct reduced iron generator, it forms a bolt in the bolt generator. The bolt generator includes a bolt storage bin and a tri-oblique pipe that are interconnected vertically. The tri-oblique pipe includes a straight pipe section and a bent pipe section that are interconnected. The inner diameter of the straight pipe section and the bent pipe section are equal. The bent pipe section is interconnected with the bolt storage bin. The adjacent end faces of the two are sealed and fixedly connected. The axis of the bent pipe section at the adjacent end face of the bolt storage bin is perpendicular to the ground.

[0011] The sidewalls of the bend and the straight section are interconnected, and the axis of the adjacent end face of the bend and the straight section forms an angle of 15-20° with the axis of the straight section in the opposite direction of material conveying.

[0012] Once the material enters the bend, it will not slide into the conveying pipeline without external force; instead, a stable plug will form within the bend.

[0013] One end of the straight pipe section is connected to the conveying pipeline, and the adjacent end faces of the two are sealed and fixedly connected.

[0014] The other end of the straight pipe section is connected to the intake short pipe, and the adjacent end faces of the two are sealed and fixedly connected.

[0015] The pulse intake valve assembly is connected to the straight section of the tri-oblique pipe via the intake short pipe.

[0016] The side wall of the slug-forming storage bin of the slug-forming transmitter is provided with a short air inlet pipe.

[0017] The thrombus-forming air source valve assembly is connected to the thrombus-forming transmitter via an air inlet short pipe.

[0018] A pressure transmitter is also installed on the connecting pipeline between the throttle gas source valve assembly and the inlet short pipe, which can monitor the changes in gas pressure in the delivery pipeline in real time.

[0019] According to the pre-set automatic conveying program, the plug-forming gas source valve group and the pulse gas source valve group are first opened. The plug-forming gas source valve group injects nitrogen gas into the plug-forming transmitter. The material in the plug-forming transmitter is continuously injected into the conveying pipeline by the airflow. The pressure transmitter installed on the plug-forming gas source valve group monitors the gas pressure in the conveying pipeline in real time. Whenever the gas pressure in the conveying pipeline is higher than 0.4-0.42MPa, the plug-forming gas source valve group is closed to stop feeding material into the conveying pipeline. Whenever the gas pressure in the conveying pipeline is lower than 0.28-0.3MPa, the plug-forming gas source valve group is opened to continue feeding material into the conveying pipeline. The pulse gas source valve group's air intake time is 300-500ms, and the interval is 2-5s.

[0020] Under the action of the pulse air source valve group and the plug-forming air source valve group, the hot direct reduced iron material in the hot direct reduced iron transmitter continuously enters the conveying pipeline for pneumatic conveying, and forms discontinuous plugs in the conveying pipeline.

[0021] Once all the material in the upper storage tank of the hot direct reduction iron transmitter has entered the bolting transmitter, step (2) is executed.

[0022] The material in the conveying pipeline is continuously transported to the solid-gas separation device. Nitrogen is passed through the gas recovery pipeline into the gas recovery device for recovery and treatment and continues to be used as a nitrogen source for reuse.

[0023] (4) The material in the solid-gas separation device is continuously transferred to the hot direct reduced iron storage bin, and the material in the hot direct reduced iron storage bin is transferred to the electric arc furnace through the feeding chute.

[0024] (5) When the material in the hot direct reduced iron storage bin reaches the set amount, stop executing steps (1) and (2). After the material in the three-sided tube of the bolting transmitter is transferred, close the bolting air source valve group. After all the material in the conveying pipeline is conveyed to the hot direct reduced iron storage bin, close the pulse air source valve group and the conveying ends.

[0025] Preferably, the conveying pipeline is further provided with a plurality of friction boosters, which are distributed sequentially along the conveying direction of the pipeline. The spacing between adjacent friction boosters is 3-5m. The friction boosters are interconnected with the conveying pipeline, and the end faces of the friction boosters adjacent to the conveying pipeline are sealed and fixedly connected by flanges.

[0026] The booster includes a connecting pipe and an air source injection device, the air source injection device being sleeved on the outer wall of the connecting pipe.

[0027] The connecting pipe is provided with an air intake channel in the circumferential direction, and the air intake channels are evenly distributed on the outer wall of the connecting pipe in the circumferential direction.

[0028] The gas injection device and the friction booster gas source valve group are connected through a short booster gas source pipe. When the friction booster gas source valve group is opened, the gas injection device injects nitrogen into the connecting pipe through the air inlet channel on the connecting pipe. The direction of the airflow is consistent with the direction of material conveying in the conveying pipeline. The friction booster and the pulse gas source valve group are opened simultaneously. The friction booster sprays gas for 300-500ms each time, with an interval of 2-3s.

[0029] Preferably, the horizontal cross-sectional shape of the air intake channel is elliptical, and the angle between the axis of the air intake channel and the axis of the connecting pipe in the opposite direction of material conveying is 15-25°.

[0030] Preferably, the connecting pipe consists of an inlet pipe section, a middle pipe section, and an outlet pipe section that are fixedly connected in sequence, with the end faces of the inlet pipe section, the middle pipe section, and the outlet pipe section being fitted and fixed together.

[0031] The end faces of the feed pipe section, the intermediate pipe section, and the discharge pipe that are adjacent to each other are all frustum-shaped surfaces. The angle between the generatrix of the frustum-shaped surface and the axis of the connecting pipe along the opposite direction of material conveying is 15-25°.

[0032] The end face of the feed pipe section adjacent to the middle pipe section is embedded into the end face of the middle pipe section adjacent to it.

[0033] The end face of the middle pipe section adjacent to the discharge pipe section is embedded into the end face of the discharge pipe section adjacent to it.

[0034] A groove is formed on one of the end faces of each pair of adjacent end faces of the feed pipe section, the middle pipe section, and the discharge pipe section. The groove is evenly distributed along the frustum surface, and the axis of the groove is equal in length and parallel to the generatrix of the frustum surface. The presence of the groove creates an air intake channel at each pair of adjacent end faces of the feed pipe section, the middle pipe section, and the discharge pipe section.

[0035] The air source jetting device consists of an inlet flange, an insulation shell, an air source distribution chamber shell, an insulation shell, and an outlet flange connected in sequence.

[0036] The feed end flange is sealed and fixedly connected to the adjacent end faces of the insulation shell, the air source distribution chamber shell, and the discharge end flange.

[0037] A sealed cavity is formed between each of the two insulating outer shells and the outer wall of the connecting pipe, and the sealed cavity is filled with thermal insulation material.

[0038] A sealed air source distribution chamber is formed between the shell of the air source distribution chamber and the inner wall of the connecting pipe. The air source distribution chamber is interconnected with the air inlet channel on the connecting pipe.

[0039] The feed pipe section of the connecting pipe has a raised ring structure on the outer wall of the end furthest from the middle pipe section.

[0040] The outer wall of the discharge section of the connecting pipe, which is away from the middle pipe section, also has a raised ring structure.

[0041] Both the inlet flange and the outlet flange are fitted onto the outer wall of the connecting pipe via a convex ring structure, forming a sealed and fixed connection with the connecting pipe.

[0042] Sealing rings are respectively installed between the feed end flange and the discharge end flange and the convex ring structure.

[0043] When the booster is working, the booster gas source valve group sprays nitrogen into the gas source distribution chamber through the booster gas source inlet short pipe. Under the action of gas pressure, the nitrogen in the gas source distribution chamber enters the connecting pipe from the inlet channel on the connecting pipe.

[0044] Preferably, the connecting pipe is made of wear-resistant silicon carbide.

[0045] Preferably, when the pressure transmitter detects a gas pressure higher than 0.48-0.5 MPa, it indicates that a blockage has occurred in the conveying pipeline. In this case, the plugging gas source valve group needs to be closed, and the unblocking gas source valve group needs to be opened to introduce pulsed high-pressure nitrogen into the conveying pipeline. The pulse intake time is 300-500 ms, and the intake interval is 1-2 s. At the same time, all the friction boosters on the conveying pipeline are opened. The friction booster sprays gas for 300-500 ms each time, and the interval is 2-3 s. The unblocking is carried out until the gas pressure in the conveying pipeline drops below 0.4-0.42 MPa. After the conveying pipeline is successfully cleared, the plugging gas source valve group is reopened to restore the normal conveying of materials. The unblocking gas source valve group is connected to the straight section of the three-sided pipe.

[0046] Preferably, the nitrogen gas enters the gas recovery device through a gas recovery pipeline for recovery treatment as follows:

[0047] The gas recovery device includes a multi-tube water cooling device, a dust collector, a gas buffer tank, and a gas conveying and pressurizing device that are connected in sequence.

[0048] Nitrogen gas is first rapidly cooled by a multi-tube water cooling system to a temperature of T < 180-280℃. Then, it undergoes ultra-clean purification filtration using a dust collector, resulting in a dust content of < 5 mg / Nm³. 3 The filtered nitrogen is introduced into a gas buffer tank. The gas in the buffer tank is pressurized by a gas delivery and pressurization device to P≥0.80-1.00MPa, and then heated by a gas heating device. The nitrogen is then used as the nitrogen source for pneumatic conveying into the gas source delivery pipeline. The gas buffer tank is also connected to a gas source replenishment device. Nitrogen is periodically replenished into the gas buffer tank according to the actual operating conditions of the system. The dust collector is a high-temperature pulse jet metal dust collector or a high-temperature pulse jet ceramic cartridge dust collector.

[0049] Preferably, the angle between the axis of the bent pipe section and the axis of the straight pipe section in the opposite direction of material conveying is 15-20°.

[0050] The present invention has the following beneficial effects:

[0051] (1) This invention, through the design of the plug-forming transmitter structure, designs the axis of the bottom tri-oblique bend section to form an angle of no more than 20° with the axis of the straight section in the opposite direction of material conveying. This design ensures that after the material enters the bend section, it will not slide from the bend section into the conveying pipeline without external force. The material will form a stable plug in the bend section. The material in the bend will only slide from the bend into the conveying pipeline when it is sprayed by the plug-forming pulse air source. After the pulse air source valve group and the plug-forming pulse air source are opened simultaneously, the material in the bend continuously enters the conveying pipeline. When the pressure in the conveying pipeline is higher than 0.4-0.42MPa, the plug-forming air source valve group is closed to stop the flow into the conveying pipeline. During material feeding, the pulse gas source valve group remains open, injecting nitrogen to propel the material forward in the conveying pipeline. This causes a drop in pressure within the pipeline. When the gas pressure drops below 0.28-0.3 MPa, the plug-in gas source valve group is reopened to continue feeding material into the pipeline. This operation creates discontinuous plugs within the pipeline, significantly slowing down the material's conveying speed. This significantly reduces wear on the inner wall of the pipeline during pneumatic conveying and lowers the probability of severe collisions between materials. It effectively solves the problems of easy jamming and breakage of hot direct reduction iron material in the conveying pipeline.

[0052] (2) In this invention, a plurality of friction boosters are arranged along the material conveying direction on the conveying pipeline. The friction boosters are interconnected with the conveying pipeline and are distributed sequentially along the conveying direction of the pipeline. The spacing between adjacent friction boosters is 3-5m. The friction boosters are interconnected with the conveying pipeline, and the end faces of the friction boosters and the conveying pipeline adjacent to each other are sealed and fixedly connected by flanges. Each friction booster includes a connecting pipe and an air source injection device. The air source injection device is sleeved on the outer wall of the connecting pipe. The connecting pipe has an air inlet channel in the circumferential direction. The gas jetting device sprays nitrogen into the connecting pipe through the air inlet channel on the connecting pipe. The direction of the air jetting is consistent with the direction of material conveying in the conveying pipe. The jetting time of each jetting by the flow booster is 300-500ms, and the interval time is 2-3s. After the flow booster and the pulse gas source valve group are opened at the same time, the flow booster intermittently sprays nitrogen into the conveying pipe, forming an air film between the material and the inner wall of the conveying pipe. This can further reduce the friction coefficient of the material against the inner wall of the conveying pipe and reduce the wear of the material against the inner wall of the conveying pipe.

[0053] (3) When the blockage material is sent into the conveying pipeline, the flow booster and the blockage clearing air source valve group are opened at the same time. The presence of the flow booster significantly reduces the gas pressure and flow rate required by the blockage clearing air source valve group, effectively shortens the time required for blockage clearing, and greatly improves production efficiency. Attached image description:

[0054] Figure 1 : A schematic diagram of the pneumatic conveying system used in the pneumatic conveying method for direct thermal reduction of iron material of the present invention.

[0055] Figure 2 : Figure 1 A magnified structural diagram of part A in the middle.

[0056] Figure 3 : A schematic diagram of the flow booster in the pneumatic conveying system used in this invention.

[0057] Figure 4 : A schematic diagram of the nitrogen recovery process in the pneumatic conveying method for direct thermal reduction of iron material used in this invention.

[0058] Figure 5 : A schematic diagram of the structure of the hot direct reduction iron transmitter in the pneumatic conveying system used in the hot direct reduction iron pneumatic conveying method of the present invention.

[0059] In the diagram, 1. Gas-based vertical shaft furnace, 2. Upper storage tank, 3. Inlet short pipe, 4. Discharge gate valve, 5. Discharge chute, 6. Bolted gas source valve assembly, 7. Pressure transmitter, 8. Double-layer bell-type feeder, 9. Hot direct reduced iron (DRI) transmitter, 10. Conveying pipeline, 11. Friction booster, 12. Bolted storage silo, 13. Pulse gas source valve assembly, 14. Friction booster gas source valve assembly, 17. Solid-gas separation device, 18. Double-layer gate-type unloader, 19. Hot direct reduced iron (DRI) storage silo, 20. Feed chute, 21. Electric arc furnace, 22. Gas recovery pipeline, 23. Gas recovery device, 24. Gas source transmission pipeline, 28. Level gauge, 29. Unblocking air source valve assembly, 1-1. Convex ring structure, 1-2. Feed pipe section, 1-3. Sealing ring, 1-4. Feed end flange, 1-5. Insulation shell, 1-6. Thermal insulation material, 1-7. Air source distribution chamber, 1-8. Middle pipe section, 1-9. Boosting air source feed short pipe, 1-10. Air inlet channel, 1-11. Boosting airflow direction, 1-12. Discharge end flange, 1-13. Discharge pipe section, 2-4. Multi-pipe water cooling device, 2-5. Dust collector, 2-6. Gas buffer tank, 2-7. Conveying gas pressurization device, 2-8. Gas heating device, 2-10. Air source replenishment device, 4-4. Bend section, 4-8. Straight pipe section. Detailed implementation method:

[0060] The present invention will be described in detail below with reference to embodiments. However, it should be understood that the following embodiments are merely illustrative examples of implementation of the present invention and are not intended to limit the scope of the present invention.

[0061] like Figure 1-5 As shown, the pneumatic conveying system used in the hot direct reduction iron material pneumatic conveying method provided by the present invention includes the following steps:

[0062] (1) At the same time, open the discharge gate valve 4 at the bottom of the gas-based vertical furnace 1 and the upper bell valve of the feeder 8 to start feeding into the feeder 8. The hot direct reduction iron material enters the feeder 8 through the discharge chute 5. When the hot direct reduction iron material in the feeder 8 reaches the set feed amount, close the discharge gate valve 4 at the bottom of the gas-based vertical furnace 1 and the upper bell valve of the feeder 8. The feeder is a double-layer bell valve type feeder.

[0063] (2) Open the lower bell valve of the feeder 8 and add all the material in the feeder 8 into the hot direct reduction iron transmitter 9. Then close the lower bell valve of the feeder 8 and simultaneously execute step (1).

[0064] (3) The hot direct reduced iron generator 9 includes an upper storage tank 2 and a bolt generator that are interconnected vertically. The volume of material in the upper storage tank 2 is not less than 1 / 2. The material does not completely fill the upper storage tank 2. After the material enters the hot direct reduced iron generator 9, it forms a bolt in the bolt generator. The bolt generator includes a bolt storage bin 12 and a tri-oblique pipe that are interconnected vertically. The tri-oblique pipe includes a straight pipe section 4-8 and a bent pipe section 4-4 that are interconnected. The inner diameters of the straight pipe section 4-8 and the bent pipe section 4-4 are equal. The bent pipe section 4-4 is interconnected with the bolt storage bin 12. The adjacent end faces of the two are sealed and fixedly connected. The axis of the bent pipe section 4-4 at the adjacent end face of the bolt storage bin 12 is perpendicular to the ground.

[0065] The side walls of the bend section 4-4 and the straight section 4-8 are interconnected. The axes of the adjacent end faces of the bend section 4-4 and the straight section 4-8 form an angle of 15-20° with the axis of the straight section 4-8 in the opposite direction of material conveying.

[0066] Once the material enters the bend section 4-4, it will not slide into the conveying pipe 10 without external force. Instead, a stable material plug will form within the bend section 4-4.

[0067] One end of the straight pipe section 4-8 is connected to the conveying pipe 10, and the adjacent end faces of the two are sealed and fixedly connected.

[0068] The other end of the straight pipe section 4-8 is connected to the intake short pipe 3, and the adjacent end faces of the two are sealed and fixedly connected.

[0069] The pulse intake valve assembly is connected to the straight section 4-8 of the tri-oblique pipe via the intake short pipe 3.

[0070] An air inlet pipe 3 is provided on the side wall of the slug-forming storage bin 12 of the slug-forming transmitter.

[0071] The thrombus-forming air source valve assembly 6 is interconnected with the thrombus-forming transmitter via the air inlet short pipe 3.

[0072] A pressure transmitter 7 is also installed on the connecting pipeline between the throttle gas source valve group 6 and the inlet short pipe 3, which can monitor the changes in gas pressure in the delivery pipeline 10 in real time.

[0073] According to the pre-set automatic conveying program, the plug-forming gas source valve group 6 and the pulse gas source valve group 13 are first opened. The plug-forming gas source valve group 6 injects nitrogen into the plug-forming transmitter. The material in the plug-forming transmitter is continuously injected into the conveying pipeline 10 by the airflow. The pressure transmitter 7 installed on the plug-forming gas source valve group 6 monitors the gas pressure in the conveying pipeline 10 in real time. Whenever the gas pressure in the conveying pipeline 10 is higher than 0.4-0.42MPa, the plug-forming gas source valve group 6 is closed to stop feeding into the conveying pipeline 10. Whenever the gas pressure in the conveying pipeline 10 is lower than 0.28-0.3MPa, the plug-forming gas source valve group 6 is opened to continue feeding into the conveying pipeline 10. The pulse gas source valve group 13 has an air intake duration of 300-500ms and an interval of 2-5s.

[0074] Under the action of the pulse air source valve group 13 and the plug-forming air source valve group 6, the hot direct reduced iron material in the hot direct reduced iron transmitter 9 continuously enters the conveying pipe 10 for pneumatic conveying, and forms discontinuous plugs in the conveying pipe 10.

[0075] Once all the material in the upper storage tank 2 of the hot direct reduction iron transmitter 9 has entered the bolting transmitter, step (2) is executed.

[0076] The material in the conveying pipeline 10 is continuously conveyed to the solid-gas separation device 17, and the nitrogen gas is passed into the gas recovery device 23 through the gas recovery pipeline 22 for recovery and reuse as a nitrogen gas source.

[0077] (4) The material in the solid-gas separation device 17 is continuously transferred to the hot direct reduced iron storage bin 19, and the material in the hot direct reduced iron storage bin 19 is transferred to the electric arc furnace 21 through the feeding chute 20.

[0078] (5) When the material in the hot direct reduced iron storage bin 19 reaches the set amount, stop executing steps (1) and (2). After the material in the three-sided tube of the bolting transmitter is transferred, close the bolting air source valve group 6. After all the material in the conveying pipeline 10 is conveyed to the hot direct reduced iron storage bin 19, close the pulse air source valve group 13 and the conveying ends.

[0079] In one specific embodiment, the conveying pipeline 10 is further provided with a plurality of friction boosters 11, which are distributed sequentially along the conveying direction of the conveying pipeline 10. The spacing between adjacent friction boosters 11 is 3-5m. The friction boosters 11 are interconnected with the conveying pipeline 10, and the adjacent end faces of the friction boosters 11 and the conveying pipeline 10 are sealed and fixedly connected by flanges.

[0080] The booster 11 includes a connecting pipe and an air source injection device, the air source injection device being sleeved on the outer wall of the connecting pipe.

[0081] The connecting pipe is provided with air intake channels 1-10 in the circumferential direction, and the air intake channels 1-10 are evenly distributed on the outer wall of the connecting pipe in the circumferential direction.

[0082] The gas injection device and the friction booster gas source valve group 14 are connected through a short booster gas source pipe. When the friction booster gas source valve group 14 is opened, the gas injection device injects nitrogen into the connecting pipe through the air inlet channel 1-10 on the connecting pipe. The direction of the airflow is consistent with the direction of material conveying in the conveying pipeline 10. The friction booster 11 and the pulse gas source valve group 13 are opened at the same time. The duration of each jet injection by the friction booster 11 is 300-500ms, and the interval is 2-3s.

[0083] In one specific embodiment, the horizontal cross-sectional shape of the air intake channel 1-10 is elliptical, and the angle between the axis of the air intake channel 1-10 and the axis of the connecting pipe in the opposite direction of material conveying is 15-25°.

[0084] In one specific embodiment, the connecting pipe is composed of an inlet pipe section 1-2, a middle pipe section 1-8, and an outlet pipe section 1-13 that are fixedly connected in sequence, with the end faces of the inlet pipe section 1-2, the middle pipe section 1-8, and the outlet pipe section 1-13 being fitted and fixed together.

[0085] The end faces of the feed pipe section 1-2, the intermediate pipe section 1-8, and the discharge pipe that are adjacent to each other are all frustum surfaces. The angle between the generatrix of the frustum surface and the axis of the connecting pipe in the opposite direction of material conveying is 15-25°.

[0086] The end face of the feed pipe section 1-2 adjacent to the middle pipe section 1-8 is embedded into the end face of the middle pipe section 1-8 adjacent to it.

[0087] The end face of the middle pipe section 1-8 adjacent to the discharge pipe section 1-13 is embedded into the end face of the discharge pipe section 1-13 adjacent to it.

[0088] Grooves are formed on one of the end faces of each pair of adjacent end faces of the feed pipe section 1-2, the middle pipe section 1-8, and the discharge pipe section 1-13. These grooves are evenly distributed along the frustum of a cylinder, with an included angle of 15-30° between the axes of adjacent grooves. The axes of the grooves are equal in length and parallel to the generatrix of the frustum of a cylinder. The width of the grooves is 0.3-0.4 mm, and the depth is 0.1-0.2 mm. The presence of these grooves creates air intake channels 1-10 at the adjacent end faces of the feed pipe section 1-2, the middle pipe section 1-8, and the discharge pipe section 1-13.

[0089] The air source jetting device consists of a feed end flange 1-4, an insulation shell 1-5, an air source distribution chamber 1-7 shell, an insulation shell 1-5, and a discharge end flange 1-12 connected in sequence.

[0090] The feed end flange 1-4 is sealed and fixedly connected to the adjacent end faces of the insulation shell 1-5, the air source distribution chamber 1-7, and the discharge end flange 1-12.

[0091] Each of the two insulating outer shells 1-5 forms a sealed cavity with the outer wall of the connecting pipe, and the sealed cavity is filled with thermal insulation material 1-6.

[0092] A sealed gas source distribution chamber 1-7 is formed between the housing of the gas source distribution chamber 1-7 and the inner wall of the connecting pipe. The gas source distribution chamber 1-7 is interconnected with the air inlet channel 1-10 on the connecting pipe.

[0093] The feed pipe section 1-2 of the connecting pipe has a raised ring structure 1-1 on the outer wall of the end furthest from the middle pipe section 1-8.

[0094] The outer wall of the discharge section 1-13 of the connecting pipe, which is away from the middle section 1-8, also has a raised ring structure 1-1.

[0095] Both the inlet flange 1-4 and the outlet flange 1-12 are fitted onto the outer wall of the connecting pipe via a convex ring structure 1-1, forming a sealed and fixed connection with the connecting pipe.

[0096] A sealing ring 1-3 is respectively installed between the feed end flange 1-4 and the discharge end flange 1-12 and the convex ring structure 1-1.

[0097] When the booster 11 is working, the booster gas source valve group 14 sprays nitrogen into the gas source distribution chamber 1-7 through the booster gas source inlet short pipe 3. Under the action of gas pressure, the nitrogen in the gas source distribution chamber 1-7 enters the connecting pipe from the inlet channel 1-10 on the connecting pipe.

[0098] In one specific embodiment, the connecting pipe is made of wear-resistant silicon carbide.

[0099] In a specific embodiment, when the pressure transmitter 7 detects a gas pressure higher than 0.48-0.5 MPa, it indicates that a blockage has occurred in the conveying pipeline 10. At this time, it is necessary to close the plugging gas source valve group 6 and open the unblocking gas source valve group 29 to introduce pulsed high-pressure nitrogen into the conveying pipeline 10. The pulse intake time is 300-500 ms, and the intake interval is 1-2 s. At the same time, all the friction boosters 11 on the conveying pipeline 10 are opened. The friction booster 11 sprays gas for 300-500 ms each time, and the interval is 2-3 s to clear the blockage until the gas pressure in the conveying pipeline 10 drops below 0.4-0.42 MPa. After the conveying pipeline 10 is successfully cleared, the plugging gas source valve group 6 is reopened to restore the normal conveying of materials. The unblocking gas source valve group 29 is interconnected with the straight pipe section 4-8 of the tri-oblique pipe.

[0100] In a specific embodiment, the nitrogen gas enters the gas recovery device 23 via the gas recovery pipe 22 for recovery treatment as follows:

[0101] The gas recovery device 23 includes a multi-tube water cooling device 2-4, a dust collector 2-5, a gas buffer tank 2-6, and a gas conveying and pressurizing device 2-7, which are connected in sequence.

[0102] Nitrogen gas is first rapidly cooled by a multi-tube water cooling device 2-4, reducing the gas temperature to T < 180-280℃. Then, a dust collector 2-5 performs ultra-clean purification filtration on the gas, ensuring that the dust content of the nitrogen gas is < 5 mg / Nm³. 3 After filtration, nitrogen is introduced into the gas buffer tank 2-6. The gas in the buffer tank is pressurized by the gas delivery and pressurization device 2-7 to P≥0.80-1.00MPa, and then heated by the gas heating device 2-8. The nitrogen is then used as the nitrogen source for pneumatic delivery into the gas source pipeline 24. The gas buffer tank 2-6 is also connected to the gas source replenishment device 2-10. Nitrogen is periodically replenished into the gas buffer tank 2-6 through the gas source replenishment device 2-10 according to the actual operation of the system.

[0103] In one specific embodiment, the angle formed by the axis of the bend section 4-4 and the axis of the straight section 4-8 in the opposite direction of material conveying is 15-20°.

[0104] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A pneumatic conveying method for hot direct reduction iron material, characterized in that, Includes the following steps: (1) Gas-based vertical furnace (1) feeds into feeder (8). Hot direct reduction iron material enters feeder (8) through discharge chute (5). When the hot direct reduction iron material in feeder (8) reaches the set feed amount, feeder (8) stops. (2) Add all the material in the feeder (8) into the hot direct reduction iron transmitter (9), then stop feeding into the hot direct reduction iron transmitter (9) and execute step (1) at the same time. (3) The hot direct reduction iron transmitter (9) includes an upper storage tank (2) and a bolt transmitter that are interconnected. The bolt transmitter includes a bolt storage bin (12) and a tri-oblique pipe that are interconnected. The tri-oblique pipe includes a straight pipe section (4-8) and a bent pipe section (4-4) that are interconnected. The bent pipe section (4-4) is interconnected with the bolt storage bin (12). The straight pipe section (4-8) is interconnected with the conveying pipe (10). The side walls of the bent pipe section and the straight pipe section are interconnected. The axis of the adjacent end face of the bent pipe section (4-4) and the axis of the straight pipe section (4-8) form an angle of ≤20° with the axis of the straight pipe section (4-8) in the opposite direction of material conveying. After the material enters the hot direct reduction iron transmitter (9), a bolt is formed in the bolt transmitter. (4) First, open the plug-forming gas source valve group (6) and the pulse gas source valve group (13). The plug-forming gas source valve group (6) sprays nitrogen into the plug-forming transmitter. The material in the plug-forming transmitter is sprayed by the airflow and continuously enters the conveying pipeline (10). The pressure transmitter (7) installed on the plug-forming gas source valve group (6) monitors the gas pressure in the conveying pipeline (10) in real time: when the gas pressure in the conveying pipeline (10) is higher than 0.4-0.42MPa, the plug-forming gas source valve group (6) is closed and the material is stopped from being fed into the conveying pipeline (10). When the gas pressure in the conveying pipe (10) is lower than 0.28-0.3MPa, the plug-forming gas source valve group (6) is opened to continue feeding material into the conveying pipe (10). Under the action of the pulse gas source valve group (13) and the plug-forming gas source valve group (6), the hot direct reduced iron material in the hot direct reduced iron transmitter (9) continuously enters the conveying pipe (10) for pneumatic conveying and forms discontinuous plugs in the conveying pipe (10). (5) When all the material in the upper storage tank (2) of the hot direct reduction iron transmitter (9) enters the bolting transmitter, step (2) is executed. (6) The material in the conveying pipeline (10) is continuously conveyed to the solid-gas separation device (17), and the nitrogen is passed into the gas recovery device (23) through the gas recovery pipeline (22) for recovery and continued to be used as a nitrogen source for reuse. (7) The material in the solid-gas separation device (17) is continuously transferred to the hot direct reduced iron storage bin (19), and the material in the hot direct reduced iron storage bin (19) is transferred to the electric arc furnace (21) through the feeding chute (20); (8) When the material in the hot direct reduced iron storage bin (19) reaches the set amount, stop executing steps (1) and (2). After the material in the three-sided tube of the bolt transmitter is transferred, close the bolt air source valve group (6). After all the material in the conveying pipeline (10) is conveyed to the hot direct reduced iron storage bin (19), close the pulse air source valve group (13) and the conveying ends.

2. The pneumatic conveying method for direct thermal reduction iron material according to claim 1, characterized in that, The volume of material in the upper storage tank (2) shall not be less than 1 / 2, and shall not fill the entire upper storage tank (2).

3. The pneumatic conveying method for hot direct reduction iron material according to claim 1, characterized in that, The conveying pipeline (10) is also provided with a number of flow boosters (11), which are distributed sequentially along the conveying direction of the conveying pipeline (10) and are connected to the conveying pipeline (10).

4. The pneumatic conveying method for hot direct reduction iron material according to claim 3, characterized in that, The booster (11) includes a connecting pipe and a gas source injection device. The gas source injection device is sleeved on the outer wall of the connecting pipe. The connecting pipe is provided with an air inlet channel (1-10) in the circumferential direction. The air inlet channel (1-10) is evenly distributed on the outer wall of the connecting pipe in the circumferential direction. The gas source injection device is connected to the booster gas source valve group (14) through the booster gas source short pipe. When the booster gas source valve group (14) is opened, the gas source injection device injects nitrogen into the connecting pipe through the air inlet channel (1-10) on the connecting pipe. The direction of the airflow is consistent with the direction of material conveying in the conveying pipeline (10).

5. The pneumatic conveying method for hot direct reduction iron material according to claim 4, characterized in that, The connecting pipe consists of a feed pipe section (1-2), a middle pipe section (1-8), and a discharge pipe section (1-13) that are fixedly connected in sequence; The end faces of the feed pipe section (1-2), the middle pipe section (1-8), and the discharge pipe section (1-13) that are adjacent to each other are fixed by fitting together with a frustum. A groove is formed on one of the end faces of each pair of adjacent end faces of the feed pipe section (1-2), the middle pipe section (1-8), and the discharge pipe section (1-13). The groove is evenly distributed along the frustum surface, and the axis of the groove is equal in length and parallel to the generatrix of the frustum surface, thereby forming an air intake channel (1-10) at each pair of adjacent end faces of the feed pipe section (1-2), the middle pipe section (1-8), and the discharge pipe section (1-13).

6. The pneumatic conveying method for hot direct reduction iron material according to claim 5, characterized in that, The connecting pipe is made of wear-resistant silicon carbide.

7. The pneumatic conveying method for hot direct reduction iron material according to claim 1, characterized in that, When the pressure transmitter (7) detects that the gas pressure is higher than 0.48-0.5MPa, the plugging gas source valve group (6) is closed and the unblocking gas source valve group (29) is opened. Pulsed high-pressure nitrogen is introduced into the conveying pipeline (10). The pulse intake time is 300-500ms and the intake interval is 1-2s. At the same time, all the flow boosters (11) on the conveying pipeline (10) are opened. The flow booster (11) sprays for 300-500ms each time and the interval is 2-3s to clear the blockage until the gas pressure in the conveying pipeline (10) drops below 0.4-0.42MPa. After the conveying pipeline (10) is successfully cleared, the plugging gas source valve group (6) is reopened to restore the normal conveying of materials. The unblocking gas source valve group (29) is connected to the straight pipe section (4-8) of the three-sided pipe.

8. The pneumatic conveying method for hot direct reduction iron material according to claim 1, characterized in that, The steps for nitrogen gas to enter the gas recovery device (23) through the gas recovery pipeline (22) for recovery treatment are as follows: Nitrogen gas is first rapidly cooled by a multi-tube water cooling device (2-4) to a temperature of T < 180-280℃. Then, a dust collector (2-5) is used to perform ultra-clean purification filtration on the gas, ensuring that the dust content of the nitrogen gas is < 5 mg / Nm³. 3 After filtration, nitrogen is introduced into the gas buffer tank (2-6). The gas in the buffer tank is pressurized by the gas delivery device (2-7) to P≥0.80-1.00MPa, and then heated by the gas heating device (2-8). The nitrogen is then used as the nitrogen source for pneumatic delivery and enters the gas source pipeline (24). The gas buffer tank (2-6) is also connected to the gas source replenishment device (2-10). Nitrogen is periodically replenished into the gas buffer tank (2-6) through the gas source replenishment device (2-10) according to the actual operation of the system.

9. A pneumatic conveying static pressure segmented pulse-type booster jack system, characterized in that, The method used is a pneumatic conveying method for direct thermal reduction of iron material as described in any one of claims 1-8.

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