Ironmaking system
By using high-temperature, low-pressure coal gas to preheat iron ore powder in a molten reduction furnace, and combining this with a scraper device to control the movement of the material layer, the problems of equipment wear and high energy consumption were solved, achieving a highly efficient iron ore powder pre-reduction and molten reduction process, and improving production efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANDONG PROVINCE METALLURGICAL ENG CO LTD
- Filing Date
- 2025-04-25
- Publication Date
- 2026-05-12
AI Technical Summary
Existing iron ore powder preheating and pre-reduction processes suffer from problems such as severe equipment wear, short lifespan, high energy consumption, and high fluidizing gas pressure, resulting in low production efficiency of molten reduction furnaces.
An iron ore powder preheating device is adopted, which uses high-temperature and low-pressure coal gas generated by the molten reduction furnace for preheating. Combined with oxygen-containing gas spray gun and solid material spray gun, the iron ore powder achieves a reverse motion reduction reaction, improves the pre-reduction degree, and controls the material layer movement through a scraper device, simplifying the equipment structure.
It improves the pre-reduction degree of iron ore powder, extends equipment life, reduces operating resistance, and enhances the production efficiency of the molten reduction furnace and the utilization efficiency of gas temperature.
Smart Images
Figure CN224227105U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to an ironmaking system that directly uses iron ore powder and coal powder to produce molten iron, belonging to the field of smelting reduction furnace technology. Background Technology
[0002] The melting reduction furnace mentioned is usually called Hismelt.
[0003] The molten reduction furnace directly uses iron ore powder and coal powder for ironmaking, eliminating the coking and sintering processes. In molten reduction ironmaking, the ore powder and coal powder are directly injected into the slag-iron molten pool, where a reduction reaction occurs, generating CO. The rising CO from the molten pool, along with the injected iron ore powder and coal powder carrier gas, carries the molten slag and iron droplets into the upper space, forming a "fountain" of slag-iron droplets. The rising CO gas and the hot air injected from the top hot air lance undergo a secondary combustion reaction, generating a large amount of heat. The heated "fountain" of slag-iron droplets carries the heat back to the molten pool.
[0004] The working pressure of a melting reduction furnace is generally less than 100 kPa.
[0005] Iron ore powder injected into the molten reduction furnace needs to be preheated and pre-reduced.
[0006] In KWINANA, Australia, the iron ore powder preheating process of the molten reduction furnace uses a circulating fluidized bed + Venturi tube + cyclone process. Due to the very high flow velocity in this process, the refractory materials suffer severe wear and have a short service life. The original plan was to preheat the iron ore powder with the high-temperature gas generated by the molten reduction furnace. However, the gas from the molten reduction furnace was not introduced into the iron ore powder preheating system even when the project was shut down.
[0007] In Shandong Molong, the preheating of iron ore powder in the molten reduction furnace adopts the rotary kiln drying and preheating process. Since the rotary kiln operates under negative pressure, the heat source for drying and preheating is pulverized coal combustion or coal gas combustion. The high-temperature flue gas generated by the molten reduction furnace cannot be used for preheating in the rotary kiln.
[0008] The iron ore powder preheating and pre-reduction process at POSCO FINEX uses a multi-stage fluidized bed process. Due to the use of a multi-stage fluidized bed, there are many pieces of equipment, the power required for fluidization is high, the resistance is high, and the fluidizing gas pressure during operation is greater than 300 kPa. Summary of the Invention
[0009] Solution to the technical problem
[0010] This ironmaking system includes an iron ore powder feeding device, an iron ore powder preheating device, an iron ore powder injection device, a pulverized coal injection system, and a smelting reduction furnace. The iron ore powder feeding device is connected to the iron ore powder preheating device, which is connected to the iron ore powder injection device, which is connected to the smelting reduction furnace. The pulverized coal injection device is connected to the smelting reduction furnace, and the smelting reduction furnace is connected to the iron ore powder preheating device. The iron ore powder preheating device is sequentially connected to the gas purification system and the gas user system.
[0011] The iron ore powder preheating device includes: a furnace body, which is a barrel-shaped structure with a feeding port at the top and / or top, a gas outlet at the top and / or top, a gas inlet at the bottom and / or bottom, and a discharge port at the bottom and / or bottom; a material tray, consisting of multiple material trays connected to the side wall of the furnace body, and multiple chambers separated by the material trays along the vertical direction, each material tray having multiple discharge ports, and adjacent chambers being connected through the discharge ports; a scraper, consisting of a scraper arm and a scraper, the scraper arm being connected to a rotating shaft, the scraper being connected to the scraper arm, and the scraper arm and scraper rotating together with the rotating shaft; a drive system, consisting of a rotating shaft and a drive device; the scraper is made of wear-resistant material, and the scraper can also be made into a rake tooth shape; the rotating shaft may have a wear-resistant protective sleeve;
[0012] The inner side of the iron ore powder preheating device cylinder is provided with heat insulation and wear-resistant materials;
[0013] The aforementioned molten reduction furnace is equipped with at least one iron ore powder preheating device;
[0014] The molten reduction furnace includes an oxygen-containing gas lance, a solid material lance, a front furnace, a slag inlet, and a reduction furnace gas outlet. The oxygen-containing gas lance is inserted into the upper part of the molten reduction furnace, and its outlet is above the slag layer. The solid material lance is inserted from the side wall of the molten reduction furnace, and its outlet is inside the slag layer.
[0015] Preferably, the rotational speed of the shaft is 0.4 to 4 r / min, and the rotational speed is adjusted by a drive device to control the residence time of the furnace charge in the iron ore powder preheating device; the drive device can be a single drive or a dual drive; the drive device can also be a lower first drive and an upper second drive.
[0016] Preferably, the iron ore powder preheating device can also be equipped with an oxygen-containing gas nozzle at a certain height to blow oxygen-containing gas into the iron ore powder preheating device and burn part of the coal gas to supplement the heat.
[0017] Preferably, the rotating shaft has a hollow structure and is cooled by a cooling medium, such as air or water.
[0018] Preferably, the material tray is made of high-temperature resistant alloy, has wear-resistant material on it, and has a discharge port.
[0019] Preferably, the rotating shaft is made of a high-temperature resistant alloy.
[0020] Preferably, the scraper arm and scraper rotate with the rotating shaft, and the scraper scrapes the material on the material tray.
[0021] Preferably, the temperature of the iron ore powder discharged from the lower outlet is ≥600℃.
[0022] Preferably, the gas generated by the molten reduction furnace is introduced into the iron ore powder preheating device, and the gas after preheating the iron ore powder is discharged from the gas outlet.
[0023] Preferably, a gas cooling and coarse dust removal device is provided between the molten reduction furnace and the iron ore powder preheating device, so that the gas temperature is reduced to the temperature required by the iron ore powder preheating device.
[0024] Preferably, the gas temperature is ≥800℃ and the gas pressure is greater than 60kPa.
[0025] Preferably, the oxygen-containing gas spray gun sprays oxygen-enriched air at a temperature of ≥1000°C.
[0026] Preferably, the oxygen-containing gas spray gun sprays oxygen at room temperature with an oxygen content of ≥80%.
[0027] Furthermore, the ironmaking process includes producing molten iron through the aforementioned ironmaking system; specifically, iron ore powder and flux are fed to the feed port of the iron ore powder preheating device via a feeding device. High-temperature gas from the molten reduction furnace enters through the gas inlet of the iron ore powder preheating device. The iron ore powder and gas move in opposite directions. The high-temperature gas heats the iron ore powder, and the CO and H2 in the gas react with the iron oxides in the iron ore powder in a reduction reaction. The heated and pre-reduced iron ore powder is discharged from the iron ore powder preheating device through the discharge port. Then, the iron ore powder is sent to the iron ore powder injection device and injected into the molten reduction furnace through the solid material spray gun. The coal powder is then... The powder injection system and solid material spray guns inject the powder into the molten reduction furnace; oxygen-containing gas is injected into the molten reduction furnace through oxygen-containing gas spray guns; the oxygen injected into the oxygen-containing gas spray guns reacts with the molten pool to generate CO and H2, which are then burned in the upper space. The heat generated heats the molten pool, and the smelting process produces molten iron and slag. The molten iron is discharged from the molten reduction furnace at regular or continuous intervals, and the slag is discharged from the molten reduction furnace at regular intervals. The gas generated during the reaction process is discharged through the gas outlet of the reduction furnace. After waste heat utilization and coarse dust removal, all or part of the gas is sent to the iron ore powder preheating device. The gas discharged from the gas outlet of the iron ore powder preheating device is then dusted and supplied to downstream users.
[0028] The advantages of this ironmaking system are: the iron ore powder preheating device uses high-temperature, low-pressure coal gas generated by the molten reduction furnace, which improves the utilization efficiency of coal gas temperature; the CO and H2 in the coal gas react with the iron ore powder to increase the pre-reduction degree of the iron ore powder and improve the production efficiency of the molten reduction furnace; the iron ore powder preheating device is simple in design, has low operating resistance, and a long service life. Attached Figure Description
[0029] Figure 1 A schematic diagram of an iron smelting system Figure I
[0030] Figure 2 This is a schematic diagram of a scraper.
[0031] Figure 3 This is a schematic diagram of tray B.
[0032] Figure 4 This is a schematic diagram of tray A.
[0033] Figure 5 A schematic diagram of an iron smelting system Figure II
[0034] Legend markings
[0035] 1 Iron ore powder feeding device; 2 Iron ore powder preheating device; 201 Iron ore powder preheating device gas outlet; 202 Material tray discharge port; 203 Scraper arm; 204 Scraper; 205 Material tray A; 206 Material tray B; 207 Discharge port; 208 First drive device; 209 Rotary shaft cooling medium inlet; 210 Gas inlet; 211 Iron ore powder inlet; 212 Rotary shaft cooling medium outlet; 213 Second drive device; 214 Rotary shaft; 215 Furnace sidewall; 3 Iron ore powder injection device; 4 Melting reduction furnace; 401 Oxygen-containing gas lance; 402 Slag layer; 403 Solid material lance; 404 Forehearth; 405 Molten iron layer; 406 Slag outlet; 407 Reduction furnace gas outlet; 408 Waste heat boiler I; 409 Coarse dust removal II; 410 Waste heat boiler II. 411 Fine dust removal II, 5 Pulverized coal injection device, 6 Fine dust removal I, 7 Gas user. Specific Implementation
[0036] Example 1
[0037] The following is an appendix Figure 1 , 2 Referring to 3 and 4, the implementation of this utility model patent is described in detail so that those skilled in the art can easily implement it. This utility model patent can be embodied in many different forms and is not limited to this description.
[0038] Raw materials: Iron ore powder: grade >61%, particle size: <8mm, moisture <10%; Coal powder: volatile matter <13%, particle size <2%.
[0039] Iron ore powder is transported from the raw material yard to the silo of iron ore powder feeding device 1, and fed into the iron ore powder inlet 211 of iron ore powder preheating device 2 via a closed hopper system and screw feeder. Iron ore powder and dolomite powder fall onto the material trays of iron ore powder feeding device 2. The material trays are divided into material trays A205 and B206, which are arranged alternately. The first drive device 208 and the second drive device 213 drive the rotating shaft 214 to drive the scraper arm 203 and scraper 204. The rotating scraper 204 scrapes the iron ore powder on the feed pan, and the iron ore powder enters the next feed pan through the feed inlet. There are 12 feed pans arranged from top to bottom along the cylinder of the iron ore preheating device 2. Each feed pan has at least four feed inlets 202. The feed inlets 202 of feed pans A205 and B206 do not overlap vertically. The iron ore powder falls layer by layer from top to bottom and is finally discharged from the discharge port 207. The rotating shaft 214 is a hollow structure with a cooling medium inlet 209 and a cooling medium outlet 212. The cooling medium is compressed air. High-temperature gas, originating from the reduction furnace gas outlet 407, is cooled and coarsely dusted before being delivered at 850°C to the gas inlet 210. The gas inlet 210 enters from the lower part of the furnace side wall 215 of the iron ore powder preheating device 2, with six inlets evenly distributed circumferentially. Upon entering the iron ore powder preheating device 2, the high-temperature gas moves upwards and counter-currently to the iron ore powder, heating it. The CO and H2 in the gas undergo a reduction reaction with the iron ore powder. The iron ore powder discharged from the discharge port 207 reaches a temperature ≥700°C and a reduction degree ≥15%. The gas discharged from the iron ore powder preheating device gas outlet 201 of the iron ore powder preheating device 2 has a temperature ≤250°C and is then purified by the gas purification unit 6 before being supplied to the gas user 7.
[0040] Iron ore powder discharged from discharge port 207 is transported to iron ore powder injection device 3 via hot chain bucket elevator, and then injected into solid material spray gun 403 and slag layer 402 of molten reduction furnace 4 by iron ore powder injection device 3. Nitrogen gas is used for injection and conveying.
[0041] Powdered coal and lime are injected into the solid material spray gun 403 and the slag layer 402 of the molten reduction furnace 4 via the powdered coal injection device 5. Nitrogen is used as the injection and conveying gas.
[0042] Oxygen-enriched hot air at 1200℃ is injected into the upper space of the molten reduction furnace 4 via an oxygen-containing gas lance 401. The CO, H2, and nitrogen generated in the molten pool of the molten reduction furnace 4 rise from the pool and burn with the injected oxygen-enriched hot air, producing a large amount of heat. The rising CO, H2, and nitrogen carry the liquid slag-iron particles into the upper space, where the heated particles carry the heat back to the molten pool. The slag-iron mixture generated in the molten reduction furnace 4 forms an iron layer 405 and a slag layer 402. The slag is discharged from the furnace periodically through the slag outlet 406, while the molten iron is discharged from the furnace periodically or continuously through the forehearth 404. A 6m diameter molten reduction furnace 4 produces 2500 tons of molten iron per day. Currently, the 6m diameter molten reduction furnace 4 in operation only produces about 1800 tons of molten iron per day.
[0043] The gas produced by the molten reduction furnace 4 has a temperature of about 1450℃ and a pressure of about 80kPa. After being cooled to about 850℃ by the waste heat boiler I 408, it is then sent to the gas inlet 210 of the iron ore powder preheating device 2 after being removed by the coarse dust collector II 409.
[0044] Example 2
[0045] With attachment Figure 5 For reference, Example 2 will be described.
[0046] Raw materials: Iron ore powder: grade >61%, particle size: <8mm, moisture <10%; Coal powder: volatile matter <13%, particle size <2%; Dolomite: particle size ≤5mm; Lime: particle size ≤3mm.
[0047] Iron ore powder is transported from the raw material yard to the silo of iron ore powder feeding device 1, and fed into the iron ore powder inlet 211 of iron ore powder preheating device 2 via a closed hopper system and screw feeder. Iron ore powder and dolomite powder fall onto the material trays of iron ore powder feeding device 2. The material trays are divided into material tray A205 and material tray B206, which are interleaved. The first drive device 208 and the second drive device 213 drive the rotating shaft 214 to drive the scraper arm 203 and scraper 204. The rotating scraper 204 scrapes the iron ore powder on the material tray, and the iron ore powder enters the next material tray along the material tray discharge port; the material tray is arranged in 16 layers from top to bottom along the iron ore powder preheating device 2 cylinder, and each material tray has more than eight material tray discharge ports 202. The material tray discharge ports 202 of material tray A205 and material tray B206 do not overlap vertically; the iron ore powder falls layer by layer from top to bottom and is finally discharged from the discharge port 207. High-temperature gas exits from the reduction furnace gas outlet 407, is cooled to 850℃ by waste heat boiler I 408, and undergoes coarse dust removal 409. One path of high-temperature gas is then sent to gas inlet 210, which enters from the lower part of the furnace side wall 215 of the iron ore powder preheating device 2. Eight gas inlets 210 are evenly arranged circumferentially. After entering the iron ore powder preheating device 2, the high-temperature gas moves upwards and counter-currently to the iron ore powder, heating it. The CO and H2 in the gas undergo a reduction reaction with the iron ore powder. The iron ore powder discharged from the discharge port 207 has a temperature ≥750℃ and a reduction degree ≥25%. The gas discharged from the iron ore powder preheating device gas outlet 201 has a temperature ≤250℃ and is then purified by gas purification 6 before being supplied to gas user 7. Another path passes through waste heat boiler II 410 and fine dust removal 411 before being supplied to gas user 7.
[0048] Iron ore powder discharged from discharge port 207 is transported to iron ore powder injection device 3 via hot chain bucket elevator, and then injected into solid material spray gun 403 and slag layer 402 of molten reduction furnace 4 by iron ore powder injection device 3. Nitrogen gas is used for injection and conveying.
[0049] Powdered coal and lime are injected into the solid material spray gun 403 and the slag layer 402 of the molten reduction furnace 4 via the powdered coal injection device 5. Nitrogen is used as the injection and conveying gas.
[0050] At room temperature oxygen and pulverized coal are injected into the upper space of the molten reduction furnace 4 through oxygen-containing gas injection gun 401.
[0051] In the molten pool of the smelting reduction furnace 4, the CO, H2, and nitrogen gases generated by the reaction rise from the pool and burn with the oxygen injected from above, producing a large amount of heat. The rising CO, H2, and nitrogen gases carry the liquid slag-iron particles into the upper space, where the heated particles carry the heat back to the molten pool. The slag-iron mixture generated in the smelting reduction furnace 4 forms an iron layer 405 and a slag layer 402. The slag is discharged from the furnace at regular intervals through the slag outlet 406, while the molten iron is discharged from the furnace at regular intervals or continuously through the forehearth 404. A 6m diameter smelting reduction furnace 4 produces 3440 tons of molten iron per day.
[0052] The gas produced by the molten reduction furnace 4 has a temperature of about 1450℃ and a pressure of about 150kPa. After being cooled to about 850℃ by the waste heat boiler I 408, it is then sent to the gas inlet 210 of the iron ore powder preheating device 2 after being removed by the coarse dust collector II 409.
[0053] The fine dust removal described in the embodiments can be wet dust removal or bag dust removal. It can also include dehydration, desulfurization, CO2 removal, etc., as needed. The gas with CO2 removed is recycled to the iron ore powder preheating device, which can improve the pre-reduction degree of iron ore powder.
[0054] Example 3
[0055] Differences from Examples 1 and 2:
[0056] The gas inlet 210 enters at the bottom of the iron ore powder preheating device 2. The bottom is equipped with an air inlet chamber and an air distribution plate. The iron ore powder forms a fluidized bed above the air distribution plate.
[0057] The contents not described in detail herein are prior art known to those skilled in the art. Although embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for this utility model. Other modifications can be readily made by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, it is not limited to the specific details and examples shown and described herein.
Claims
1. An iron smelting system, characterized in that, It includes an iron ore powder feeding device, an iron ore powder preheating device, an iron ore powder injection device, a pulverized coal injection system, and a molten reduction furnace; the iron ore powder feeding device is connected to the iron ore powder preheating device, the iron ore powder preheating device is connected to the iron ore powder injection device, the iron ore powder injection device is connected to the molten reduction furnace, the pulverized coal injection system is connected to the molten reduction furnace, and the molten reduction furnace is connected to the iron ore powder preheating device. The iron ore powder preheating device includes: a furnace body, which is a barrel-shaped structure with a feeding port at the top and / or top, a gas outlet at the top and / or top, a gas inlet at the bottom and / or bottom, and a discharge port at the bottom and / or bottom; a material tray, consisting of multiple material trays connected to the side wall of the furnace body, and multiple chambers separated by the material trays along the vertical direction, each material tray having multiple discharge ports, and adjacent chambers being connected through the discharge ports; a scraper, consisting of a scraper arm and a scraper, the scraper arm being connected to a rotating shaft, the scraper being connected to the scraper arm, and the scraper arm and scraper rotating together with the rotating shaft; and a drive system, consisting of a rotating shaft and a drive device. The molten reduction furnace includes an oxygen-containing gas spray gun, a solid material spray gun, a front furnace, a slag inlet, and a reduction furnace gas outlet.
2. The ironmaking system as described in claim 1, characterized in that, The shaft is a hollow structure and is cooled by a cooling medium.
3. The ironmaking system as described in claim 1, characterized in that, The material tray is made of high-temperature resistant alloy, has wear-resistant material on it, and has a discharge port.
4. The ironmaking system as described in claim 1, characterized in that, The scraper arm and scraper rotate with the rotating shaft, and the scraper scrapes the material on the material tray.
5. The ironmaking system as described in claim 1, characterized in that, The temperature of the iron ore powder discharged from the discharge port is ≥600℃.
6. The ironmaking system as described in claim 1, characterized in that, The gas generated by the molten reduction furnace is fed into the iron ore powder preheating device, and the gas after preheating the iron ore powder is discharged from the gas outlet.
7. The ironmaking system as described in claim 6, characterized in that, The gas temperature is ≥800℃.
8. The ironmaking system as described in claim 1, characterized in that, The oxygen-containing gas spray gun sprays oxygen-enriched air at a temperature of ≥1000℃.
9. The ironmaking system as described in claim 1, characterized in that, The oxygen-containing gas spray gun sprays oxygen at room temperature with an oxygen content of ≥80%.